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Tae‐Ho Lee

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DOI: 10.1093/nar/gkr1293
2012
Cited 4,212 times
MCScanX: a toolkit for detection and evolutionary analysis of gene synteny and collinearity
MCScan is an algorithm able to scan multiple genomes or subgenomes in order to identify putative homologous chromosomal regions, and align these regions using genes as anchors. The MCScanX toolkit implements an adjusted MCScan algorithm for detection of synteny and collinearity that extends the original software by incorporating 14 utility programs for visualization of results and additional downstream analyses. Applications of MCScanX to several sequenced plant genomes and gene families are shown as examples. MCScanX can be used to effectively analyze chromosome structural changes, and reveal the history of gene family expansions that might contribute to the adaptation of lineages and taxa. An integrated view of various modes of gene duplication can supplement the traditional gene tree analysis in specific families. The source code and documentation of MCScanX are freely available at http://chibba.pgml.uga.edu/mcscan2/.
DOI: 10.1126/science.1253435
2014
Cited 1,862 times
Early allopolyploid evolution in the post-Neolithic <i>Brassica napus</i> oilseed genome
The genomic origins of rape oilseed Many domesticated plants arose through the meeting of multiple genomes through hybridization and genome doubling, known as polyploidy. Chalhoub et al. sequenced the polyploid genome of Brassica napus , which originated from a recent combination of two distinct genomes approximately 7500 years ago and gave rise to the crops of rape oilseed (canola), kale, and rutabaga. B. napus has undergone multiple events affecting differently sized genetic regions where a gene from one progenitor species has been converted to the copy from a second progenitor species. Some of these gene conversion events appear to have been selected by humans as part of the process of domestication and crop improvement. Science , this issue p. 950
DOI: 10.1038/ng.919
2011
Cited 1,787 times
The genome of the mesopolyploid crop species Brassica rapa
We report the annotation and analysis of the draft genome sequence of Brassica rapa accession Chiifu-401-42, a Chinese cabbage. We modeled 41,174 protein coding genes in the B. rapa genome, which has undergone genome triplication. We used Arabidopsis thaliana as an outgroup for investigating the consequences of genome triplication, such as structural and functional evolution. The extent of gene loss (fractionation) among triplicated genome segments varies, with one of the three copies consistently retaining a disproportionately large fraction of the genes expected to have been present in its ancestor. Variation in the number of members of gene families present in the genome may contribute to the remarkable morphological plasticity of Brassica species. The B. rapa genome sequence provides an important resource for studying the evolution of polyploid genomes and underpins the genetic improvement of Brassica oil and vegetable crops.
DOI: 10.1038/nature11798
2012
Cited 1,081 times
Repeated polyploidization of Gossypium genomes and the evolution of spinnable cotton fibres
The Gossypium genus is used to investigate emergent consequences of polyploidy in cotton species; comparative genomic analyses reveal a complex evolutionary history including interactions among subgenomes that result in genetic novelty in elite cottons and provide insight into the evolution of spinnable fibres. A phylogenetic and genomic study of plants of the cotton genus Gossypium provides insights into the role of polyploidy in the angiosperm evolution, and specifically, in the emergence of spinnable fibres in domesticated cottons. The authors show that an abrupt five- to sixfold ploidy increase about 60 million years ago, and allopolyploidy reuniting divergent genomes approximately 1–2 million years ago, conferred a roughly 30-fold duplication of ancestral flowering plant genes in the 'elite' cottons G. hirsutum and G. barbadense compared to their presumed progenitor G. raimondii. Polyploidy often confers emergent properties, such as the higher fibre productivity and quality of tetraploid cottons than diploid cottons bred for the same environments1. Here we show that an abrupt five- to sixfold ploidy increase approximately 60 million years (Myr) ago, and allopolyploidy reuniting divergent Gossypium genomes approximately 1–2 Myr ago2, conferred about 30–36-fold duplication of ancestral angiosperm (flowering plant) genes in elite cottons (Gossypium hirsutum and Gossypium barbadense), genetic complexity equalled only by Brassica3 among sequenced angiosperms. Nascent fibre evolution, before allopolyploidy, is elucidated by comparison of spinnable-fibred Gossypium herbaceum A and non-spinnable Gossypium longicalyx F genomes to one another and the outgroup D genome of non-spinnable Gossypium raimondii. The sequence of a G. hirsutum AtDt (in which ‘t’ indicates tetraploid) cultivar reveals many non-reciprocal DNA exchanges between subgenomes that may have contributed to phenotypic innovation and/or other emergent properties such as ecological adaptation by polyploids. Most DNA-level novelty in G. hirsutum recombines alleles from the D-genome progenitor native to its New World habitat and the Old World A-genome progenitor in which spinnable fibre evolved. Coordinated expression changes in proximal groups of functionally distinct genes, including a nuclear mitochondrial DNA block, may account for clusters of cotton-fibre quantitative trait loci affecting diverse traits. Opportunities abound for dissecting emergent properties of other polyploids, particularly angiosperms, by comparison to diploid progenitors and outgroups.
DOI: 10.1038/ncomms4930
2014
Cited 930 times
The Brassica oleracea genome reveals the asymmetrical evolution of polyploid genomes
Polyploidization has provided much genetic variation for plant adaptive evolution, but the mechanisms by which the molecular evolution of polyploid genomes establishes genetic architecture underlying species differentiation are unclear. Brassica is an ideal model to increase knowledge of polyploid evolution. Here we describe a draft genome sequence of Brassica oleracea, comparing it with that of its sister species B. rapa to reveal numerous chromosome rearrangements and asymmetrical gene loss in duplicated genomic blocks, asymmetrical amplification of transposable elements, differential gene co-retention for specific pathways and variation in gene expression, including alternative splicing, among a large number of paralogous and orthologous genes. Genes related to the production of anticancer phytochemicals and morphological variations illustrate consequences of genome duplication and gene divergence, imparting biochemical and morphological variation to B. oleracea. This study provides insights into Brassica genome evolution and will underpin research into the many important crops in this genus.
DOI: 10.1093/nar/gks1104
2012
Cited 498 times
PGDD: a database of gene and genome duplication in plants
Genome duplication (GD) has permanently shaped the architecture and function of many higher eukaryotic genomes. The angiosperms (flowering plants) are outstanding models in which to elucidate consequences of GD for higher eukaryotes, owing to their propensity for chromosomal duplication or even triplication in a few cases. Duplicated genome structures often require both intra- and inter-genome alignments to unravel their evolutionary history, also providing the means to deduce both obvious and otherwise-cryptic orthology, paralogy and other relationships among genes. The burgeoning sets of angiosperm genome sequences provide the foundation for a host of investigations into the functional and evolutionary consequences of gene and GD. To provide genome alignments from a single resource based on uniform standards that have been validated by empirical studies, we built the Plant Genome Duplication Database (PGDD; freely available at http://chibba.agtec.uga.edu/duplication/), a web service providing synteny information in terms of colinearity between chromosomes. At present, PGDD contains data for 26 plants including bryophytes and chlorophyta, as well as angiosperms with draft genome sequences. In addition to the inclusion of new genomes as they become available, we are preparing new functions to enhance PGDD.
DOI: 10.1016/j.actamat.2010.01.056
2010
Cited 336 times
Correlation between stacking fault energy and deformation microstructure in high-interstitial-alloyed austenitic steels
The correlation between stacking fault energy (SFE) and deformation microstructure of high-interstitial-alloyed austenitic Fe–18Cr–10Mn–(N or N + C) alloys was investigated. As the content of the interstitial elements increased, the deformation microstructure changed in a sequence strain-induced martensitic transformation, mixture of martensite and twin, and finally deformation twin. The SFE, playing an important role in the transition of deformation microstructure, was evaluated by the Rietveld whole-profile fitting combined with the double-Voigt size–strain analysis for neutron diffraction profiles of tensile-strained bulk samples. At fixed N + C content, the ratio of mean-squared strain to stacking fault probability remained constant regardless of the accumulated strain, whereas the ratio gradually increased with increasing N + C content. Almost linear dependence of measured SFE on N + C content could be established. According to the SFE, deformation bands exhibited distinct substructures, and their particular intersecting behavior resulted in the formation of different types of products (secondary ε martensite, α′ martensite and secondary twin) at the intersecting regions.
DOI: 10.1038/ncomms3445
2013
Cited 282 times
Draft genome sequence of the mulberry tree Morus notabilis
Human utilization of the mulberry-silkworm interaction started at least 5,000 years ago and greatly influenced world history through the Silk Road. Complementing the silkworm genome sequence, here we describe the genome of a mulberry species Morus notabilis. In the 330-Mb genome assembly, we identify 128 Mb of repetitive sequences and 29,338 genes, 60.8% of which are supported by transcriptome sequencing. Mulberry gene sequences appear to evolve ~3 times faster than other Rosales, perhaps facilitating the species' spread worldwide. The mulberry tree is among a few eudicots but several Rosales that have not preserved genome duplications in more than 100 million years; however, a neopolyploid series found in the mulberry tree and several others suggest that new duplications may confer benefits. Five predicted mulberry miRNAs are found in the haemolymph and silk glands of the silkworm, suggesting interactions at molecular levels in the plant-herbivore relationship. The identification and analyses of mulberry genes involved in diversifying selection, resistance and protease inhibitor expressed in the laticifers will accelerate the improvement of mulberry plants.
DOI: 10.1016/j.biortech.2011.03.037
2011
Cited 269 times
Reuse of effluent water from a municipal wastewater treatment plant in microalgae cultivation for biofuel production
This study assessed the usability of effluent water discharged from a secondary municipal wastewater treatment plant for mass cultivation of microalgae for biofuel production. It was observed that bacteria and protozoa in the effluent water exerted a negative impact on the growth of Chlorella sp. 227. To reduce the effect, filtration or UV-radiation were applied on the effluent water as pre-treatment methods. Of all the pretreatment options tested, the filtration (by 0.2 μm) resulted in the highest biomass and lipid productivity. To be comparable with the growth in the autoclaved effluent water, the filtration with a proper pore size filter (less than 0.45 μm) or UV-B radiation of a proper dose (over 1620 mJ cm(-2)) are proposed. These findings led us to conclude that the utilization can be realized only when bacteria and other microorganisms are greatly reduced or eliminated from the effluent prior to its use.
DOI: 10.1007/s11661-009-0124-7
2009
Cited 238 times
Influence of Al on the Microstructural Evolution and Mechanical Behavior of Low-Carbon, Manganese Transformation-Induced-Plasticity Steel
Microstructural design with an Al addition is suggested for low-carbon, manganese transformation-induced-plasticity (Mn TRIP) steel for application in the continuous-annealing process. With an Al content of 1 mass pct, the competition between the recrystallization of the cold-rolled microstructure and the austenite formation cannot be avoided during intercritical annealing, and the recrystallization of the deformed matrix does not proceed effectively. The addition of 3 mass pct Al, however, allows nearly complete recrystallization of the deformed microstructure by providing a dual-phase cold-rolled structure consisting of ferrite and martensite and by suppressing excessive austenite formation at a higher annealing temperature. An optimized annealing condition results in the room-temperature stability of the intercritical austenite in Mn TRIP steel containing 3 mass pct Al, permitting persistent transformation to martensite during tensile deformation. The alloy presents an excellent strength-ductility balance combining a tensile strength of approximately 1 GPa with a total elongation over 25 pct, which is comparable to that of Mn TRIP steel subjected to batch-type annealing.
DOI: 10.1016/j.neuroimage.2016.05.076
2016
Cited 180 times
Heart rate variability is associated with amygdala functional connectivity with MPFC across younger and older adults
The ability to regulate emotion is crucial to promote well-being. Evidence suggests that the medial prefrontal cortex (mPFC) and adjacent anterior cingulate (ACC) modulate amygdala activity during emotion regulation. Yet less is known about whether the amygdala–mPFC circuit is linked with regulation of the autonomic nervous system and whether the relationship differs across the adult lifespan. The current study tested the hypothesis that heart rate variability (HRV) reflects the strength of mPFC–amygdala interaction across younger and older adults. We recorded participants' heart rates at baseline and examined whether baseline HRV was associated with amygdala–mPFC functional connectivity during rest. We found that higher HRV was associated with stronger functional connectivity between the amygdala and the mPFC during rest across younger and older adults. In addition to this age-invariant pattern, there was an age-related change, such that greater HRV was linked with stronger functional connectivity between amygdala and ventrolateral PFC (vlPFC) in younger than in older adults. These results are in line with past evidence that vlPFC is involved in emotion regulation especially in younger adults. Taken together, our results support the neurovisceral integration model and suggest that higher heart rate variability is associated with neural mechanisms that support successful emotional regulation across the adult lifespan.
DOI: 10.1016/j.neurobiolaging.2015.09.019
2016
Cited 163 times
Neuromelanin marks the spot: identifying a locus coeruleus biomarker of cognitive reserve in healthy aging
Leading a mentally stimulating life may build up a reserve of neural and mental resources that preserve cognitive abilities in late life. Recent autopsy evidence links neuronal density in the locus coeruleus (LC), the brain's main source of norepinephrine, to slower cognitive decline before death, inspiring the idea that the noradrenergic system is a key component of reserve (Robertson, I. H. 2013. A noradrenergic theory of cognitive reserve: implications for Alzheimer's disease. Neurobiol. Aging. 34, 298–308). Here, we tested this hypothesis using neuromelanin-sensitive magnetic resonance imaging to visualize and measure LC signal intensity in healthy younger and older adults. Established proxies of reserve, including education, occupational attainment, and verbal intelligence, were linearly correlated with LC signal intensity in both age groups. Results indicated that LC signal intensity was significantly higher in older than younger adults and significantly lower in women than in men. Consistent with the LC-reserve hypothesis, both verbal intelligence and a composite reserve score were positively associated with LC signal intensity in older adults. LC signal intensity was also more strongly associated with attentional shifting ability in older adults with lower cognitive reserve. Together these findings link in vivo estimates of LC neuromelanin signal intensity to cognitive reserve in normal aging.
DOI: 10.1016/j.cej.2017.02.005
2017
Cited 141 times
Complete nitrogen removal by simultaneous nitrification and denitrification in flat-panel air-cathode microbial fuel cells treating domestic wastewater
Microbial fuel cells (MFCs) can treat organic compounds from domestic wastewater without aeration, but an additional procedure is required to remove nitrogen. This study developed a flat-panel air-cathode MFC (FA-MFC) that was comprised of five MFC units connected in series and operated to remove organic and nitrogen compounds from domestic wastewater with a short hydraulic retention time (HRT) of 2.5 h. During eight months of operation, the removal efficiencies of chemical oxygen demand (COD) and total nitrogen (TN) increased, reaching 85% and 94%, respectively, and the effluent COD and TN concentrations were 20.7 ± 2.5 mg/L and 1.7 ± 0.1 mg/L, respectively. The greatest removals of COD and TN were in the first and second unit (0.62 kg-N/m3/d of TN removal rate). The FA-MFC system allowed simultaneous removals of COD and TN from domestic wastewater, although it led to minimal power output (6.3 W/m3 in the first unit). Because any abiotic ammonia loss was not found under the supplied potential of ∼1.1 V at a short HRT of 30 min, the biological nitrogen removal was thought as a dominant mechanism for TN removal in the FA-MFCs. Microbial community analysis revealed that, near the cathode, Nitrosomonas-like strains contributed to nitrification and Nitratireductor-like strains led to denitrification. Acidovorax-like strains, known for their metabolic diversity, were ubiquitous and appeared to contribute to organics and nitrogen removal in anode and cathode biofilms. This study provides proof of concept that the FA-MFC system has a promise for energy sustainable wastewater treatment.
DOI: 10.1016/j.watres.2021.117491
2021
Cited 130 times
Nano zero-valent iron improves anammox activity by promoting the activity of quorum sensing system
The addition of nano zero-valent iron (nZVI) has been proven to improve the efficiency of the anammox process, however, the mechnism is not clear. Here, the effect of nZVI on anammox microbial community was studied by metagenomic sequencing methods. It was found that 50 mg/L nZVI indeed promoted the removal of NH4+ and NO2− of the anammox reactor and significantly improved the relative abundance of AnAOB (Ca. Brocadia) from 42.1% to 52.5%. What's more, 50 mg/L nZVI increased the abundance of c-di-GMP synthesized protein from 148 rpmr to 252 rpmr in the microbial community and decreased the abundance of c-di-GMP degradation protein from 238 rpmr to 204 rpmr, which indirectly led to the enrichment of c-di-GMP in the microbial community. The enrichment of c-di-GMP reduced the motility of microorganisms in the reactor and promoted the secretion of extracellular polymers by bacteria, which is beneficial to the formation of sludge particles in the anammox reactor. In conclusion, this research clarified the mechanism of nZVI promoting the anammox process and provided theoretical guidance for the engineering application of anammox.
DOI: 10.1016/j.actamat.2004.07.031
2004
Cited 193 times
A model for deformation behavior and mechanically induced martensitic transformation of metastable austenitic steel
A microstructure-based computational model, which can describe the transformation-induced plasticity (TRIP) accompanying the mechanically induced martensitic transformation in metastable austenitic steel, was suggested. The martensitic transformation kinetics was assumed as a nucleation-controlled phenomenon. The probability, which the nucleation site would really act, was derived for each martensitic variant as a function of the interaction energy between externally applied stress state and lattice deformation. The increase of nucleation site in the austenite due to the plastic deformation was formulated as the increase of the shear-band intersection. The permanent strain originated from the transformation of austenite into martensite was evaluated by assessing the difference of the nucleation rate of martensitic variants. A self-consistent model was employed to predict the deformation behavior of each phase in the steel. The model was then implemented in an iterative program based on the radial return method to simulate the deformation behavior of the steel under various stress states. The calculated results were compared with the experimental data measured under the uniaxial tension and simple shear. In addition, when various external forces are acting, the resulting effect on the Ms temperature was calculated by the model and compared with the reported data.
DOI: 10.1007/s00253-008-1451-0
2008
Cited 170 times
Application of biocathode in microbial fuel cells: cell performance and microbial community
DOI: 10.1021/jm061243q
2007
Cited 167 times
Synthesis and Evaluation of 1,2,3-Triazole Containing Analogues of the Immunostimulant α-GalCer
α-GalCer is the first defined and most potent agonistic antigen of the T cell receptor of natural killer T cells. We have prepared a series of 1,2,3-triazole-containing α-GalCer analogues in which the lipid chain lengths have been incrementally varied. We found that this isosteric replacement of α-GalCer's amide moiety with triazole increases the IL-4 versus IFN-γ bias of released cytokines. The stimulatory effect was influenced by the length of the attached chain. In particular, the long-chained triazole analogues have a comparable stimulatory effect on cytokine production as α-GalCer and exhibit a stronger Th2 cytokine response.
DOI: 10.1016/j.biortech.2012.12.176
2013
Cited 153 times
Microalgae cultivation for bioenergy production using wastewaters from a municipal WWTP as nutritional sources
In order to reduce input cost for microalgal cultivation, we investigated the feasibility of wastewater taken from a municipal WWTP in Busan, Korea as wastewater nutrients. The wastewaters used in this study were the effluent from a primary settling tank (PS), the effluent from an anaerobic digestion tank (AD), the conflux of wastewaters rejected from sludge-concentrate tanks and dewatering facilities (CR), and two combined wastewaters of AD:PS (10:90, v/v) and AD:CR (10:90, v/v). Chlorella sp. ADE5, which was isolated from the AD, was selected for the feasibility test. The highest biomass production (3.01 g-dry cell weight per liter) of the isolate was obtained with the combined wastewater ADCR, and it was 1.72 times higher than that with BG 11 medium. Interestingly, the cells cultivated with wastewater containing PS wastewater were easily separated from the culture and improved lipid content, especially oleic acid content, in their cells.
DOI: 10.1016/j.biortech.2013.06.017
2013
Cited 143 times
Evaluation of thermal, ultrasonic and alkali pretreatments on mixed-microalgal biomass to enhance anaerobic methane production
Anaerobic digestion was regarded as one of the ways to recover energy from mixed-microalgae biomass in this study. After applying thermal-, ultrasonic-, and alkali-pretreatments to raw microalgae biomass to promote the digestion efficiency, a biochemical methane potential was investigated to evaluate the effectiveness of the pre-treatments for the purpose. As the pretreatment intensity increased, the solubilization of the mixed microalgae increased. However, the increased solubilization was not followed proportionally by the increased methane production. The highest methane productivity was achieved by the thermal-pretreatment at 120 °C (405 mL CH4/g-VS), which was 1.2 times higher than that of the non-pretreatment condition (336 mL CH4/g-VS). The net energy analysis revealed that only the pretreatment adjusted to pH 9 yielded a slightly higher energy gains (12.8 kJ/g-VS) than that of non-pretreatment condition (11.9 kJ/g-VS). These findings recommend direct supply of microalgae biomass for anaerobic digestion.
DOI: 10.1016/j.corsci.2014.08.021
2014
Cited 139 times
Interpretation of the relation between ferrite fraction and pitting corrosion resistance of commercial 2205 duplex stainless steel
The relation among pitting corrosion resistance, galvanic corrosion rate and phase fraction (44–63 vol% of ferrite phase) of UNS S32205/S31803 duplex stainless steel was investigated. The highest pitting potential was observed in the sample comprising 57 vol% of ferrite, and it decreased with increase in the phase imbalance. In the sample with 57 vol% ferrite fraction, the lowest galvanic corrosion rate between the ferrite and austenite phases was observed. It was found that the pitting corrosion resistance of the alloy samples comprising various ferrite fractions was primarily determined by the galvanic corrosion resistance between the two constituent phases.
DOI: 10.1016/j.molp.2015.04.004
2015
Cited 135 times
Genome Alignment Spanning Major Poaceae Lineages Reveals Heterogeneous Evolutionary Rates and Alters Inferred Dates for Key Evolutionary Events
Multiple comparisons among genomes can clarify their evolution, speciation, and functional innovations. To date, the genome sequences of eight grasses representing the most economically important Poaceae (grass) clades have been published, and their genomic-level comparison is an essential foundation for evolutionary, functional, and translational research. Using a formal and conservative approach, we aligned these genomes. Direct comparison of paralogous gene pairs all duplicated simultaneously reveal striking variation in evolutionary rates among whole genomes, with nucleotide substitution slowest in rice and up to 48% faster in other grasses, adding a new dimension to the value of rice as a grass model. We reconstructed ancestral genome contents for major evolutionary nodes, potentially contributing to understanding the divergence and speciation of grasses. Recent fossil evidence suggests revisions of the estimated dates of key evolutionary events, implying that the pan-grass polyploidization occurred ∼96 million years ago and could not be related to the Cretaceous-Tertiary mass extinction as previously inferred. Adjusted dating to reflect both updated fossil evidence and lineage-specific evolutionary rates suggested that maize subgenome divergence and maize-sorghum divergence were virtually simultaneous, a coincidence that would be explained if polyploidization directly contributed to speciation. This work lays a solid foundation for Poaceae translational genomics.
DOI: 10.1016/j.biortech.2010.08.031
2011
Cited 107 times
Development of a simultaneous partial nitrification and anaerobic ammonia oxidation process in a single reactor
Up-flow oxygen-controlled biofilm reactors equipped with a non-woven fabric support were used as a single reactor system for autotrophic nitrogen removal based on a combined partial nitrification and anaerobic ammonium oxidation (anammox) reaction. The up-flow biofilm reactors were initiated as either a partial nitrifying reactor or an anammox reactor, respectively, and simultaneous partial nitrification and anammox was established by careful control of the aeration rate. The combined partial nitrification and anammox reaction was successfully developed in both biofilm reactors without additional biomass inoculation. The reactor initiated as the anammox reactor gave a slightly higher and more stable mean nitrogen removal rate of 0.35 (±0.19) kg-N m(-3) d(-1) than the reactor initiated as the partial nitrifying reactor (0.23 (±0.16) kg-N m(-3) d(-1)). FISH analysis revealed that the biofilm in the reactor started as the anammox reactor were composed of anammox bacteria located in inner anoxic layers that were surrounded by surface aerobic AOB layers, whereas AOB and anammox bacteria were mixed without a distinguishable niche in the biofilm in the reactor started as the partial nitrifying reactor. However, it was difficult to efficiently maintain the stable partial nitrification owing to inefficient aeration in the reactor, which is a key to development of the combined partial nitrification and anammox reaction in a single biofilm reactor.
DOI: 10.1523/jneurosci.2097-17.2017
2018
Cited 105 times
Locus Coeruleus Activity Strengthens Prioritized Memories Under Arousal
Recent models posit that bursts of locus ceruleus (LC) activity amplify neural gain such that limited attention and encoding resources focus even more on prioritized mental representations under arousal. Here, we tested this hypothesis in human males and females using fMRI, neuromelanin MRI, and pupil dilation, a biomarker of arousal and LC activity. During scanning, participants performed a monetary incentive encoding task in which threat of punishment motivated them to prioritize encoding of scene images over superimposed objects. Threat of punishment elicited arousal and selectively enhanced memory for goal-relevant scenes. Furthermore, trial-level pupil dilations predicted better scene memory under threat, but were not related to object memory outcomes. fMRI analyses revealed that greater threat-evoked pupil dilations were positively associated with greater scene encoding activity in LC and parahippocampal cortex, a region specialized to process scene information. Across participants, this pattern of LC engagement for goal-relevant encoding was correlated with neuromelanin signal intensity, providing the first evidence that LC structure relates to its activation pattern during cognitive processing. Threat also reduced dynamic functional connectivity between high-priority (parahippocampal place area) and lower-priority (lateral occipital cortex) category-selective visual cortex in ways that predicted increased memory selectivity. Together, these findings support the idea that, under arousal, LC activity selectively strengthens prioritized memory representations by modulating local and functional network-level patterns of information processing.SIGNIFICANCE STATEMENT Adaptive behavior relies on the ability to select and store important information amid distraction. Prioritizing encoding of task-relevant inputs is especially critical in threatening or arousing situations, when forming these memories is essential for avoiding danger in the future. However, little is known about the arousal mechanisms that support such memory selectivity. Using fMRI, neuromelanin MRI, and pupil measures, we demonstrate that locus ceruleus (LC) activity amplifies neural gain such that limited encoding resources focus even more on prioritized mental representations under arousal. For the first time, we also show that LC structure relates to its involvement in threat-related encoding processes. These results shed new light on the brain mechanisms by which we process important information when it is most needed.
DOI: 10.1038/s41562-018-0344-1
2018
Cited 93 times
Arousal increases neural gain via the locus coeruleus–noradrenaline system in younger adults but not in older adults
In younger adults, arousal amplifies attentional focus to the most salient or goal-relevant information while suppressing other information. A computational model of how the locus coeruleus-norepinephrine (LC-NE) system can implement this increased selectivity under arousal and an fMRI study comparing how arousal affects younger and older adults' processing indicate that the amplification of salient stimuli and the suppression of non-salient stimuli are separate processes, with aging affecting suppression without impacting amplification under arousal. In the fMRI study, arousal increased processing of salient stimuli and decreased processing of non-salient stimuli for younger adults. In contrast, for older adults, arousal increased processing of both low and high salience stimuli, generally increasing excitatory responses to visual stimuli. Older adults also showed decline in LC functional connectivity with frontoparietal networks that coordinate attentional selectivity. Thus, among older adults, arousal increases the potential for distraction from non-salient stimuli.
DOI: 10.1016/j.actamat.2018.01.051
2018
Cited 88 times
Investigations of the microstructure evolution and tensile deformation behavior of austenitic Fe-Mn-Al-C lightweight steels and the effect of Mo addition
A series of Fe-30 wt%Mn-10.5 wt%Al-1.1 wt%C steels with Mo addition from 0 to 5 wt% were prepared to investigate the effect of Mo on the microstructure and tensile deformation behavior of austenitic lightweight steel. When the Mo content was below 4 wt%, the microstructure of solution-treated samples consisted of austenite and κ–carbide, while Mo-enriched M6C and M23C6 carbides were additionally precipitated in samples containing Mo more than 4 wt% during a solution treatment at 1050 °C. These carbides inhibited austenite grain growth during the solution treatment, resulting in significant grain refinement in the samples containing more that 4 wt% of Mo. Tensile test results showed that the yield strength gradually decreased with an increase in the Mo content up to 3 wt% due to the suppression of κ–carbide precipitation, whereas it significantly increased when the Mo content exceeded 4 wt% due to grain refinement and precipitation strengthening caused by Mo-enriched carbides. During the tensile deformation, the strain hardening rates of all alloys increased and then the deformation mode subsequently changed with an increase in the Mo content from shearband-induced plasticity (SIP) to microband-induced plasticity (MBIP). Finally, the change in the κ-carbide precipitation behavior upon the addition of Mo and its effect on the deformation behavior were carefully analyzed and discussed through nanoindentation experiments, first-principles calculations and atom probe tomography analyses.
DOI: 10.1016/j.jallcom.2018.10.253
2019
Cited 85 times
Effect of Mo and Cr additions on the microstructure, mechanical properties and pitting corrosion resistance of austenitic Fe-30Mn-10.5Al-1.1C lightweight steels
Five Fe-30 wt%Mn-10.5 wt%Al-1.1 wt%C steels containing different Mo and Cr contents were prepared to investigate the effect of Mo and Cr addition on the microstructure, mechanical properties and pitting corrosion resistance of austenitic lightweight steels. The microstructures of all samples after solution treatment at 1050 °C consisted of austenite and κ-carbide, while DO3 ordered phases were additionally formed in samples containing 3 wt%Mo-3wt%Cr or 5 wt%Cr. The results of Nanoindentation tests indicated that the intrinsic strength of the austenite matrix decreased with the addition of Mo and Cr due to the suppression of κ-carbide precipitation and then the strength of the DO3 phase is equal or higher as compared to the austenite matrix. The tensile tests also showed that the yield strength decreased when 3 wt%Mo or 3 wt%Cr was added due to the suppression of κ-carbide precipitation, whereas it increased with further additions of Mo and Cr in both cases due to the formation of a DO3 ordered phases and grain refinement. Electrochemical tests showed that the resistance to pitting corrosion was improved by the addition of Mo and Cr due to the formation of a protective passive film; however, the excessive additions of Mo or Cr adversely deteriorated the resistance to pitting corrosion as the DO3 ordered phase which acted as pit initiation sites.
DOI: 10.1016/j.jbiosc.2014.06.016
2015
Cited 83 times
Autotrophic denitrification performance and bacterial community at biocathodes of bioelectrochemical systems with either abiotic or biotic anodes
Two-chamber bioelectrochemical systems (BESs) have recently been developed for nitrate removal from nitrate-contaminated water. In this study, we compared the nitrate removal performance of biocathodes of BESs when using abiotic and biotic anodes. Acetate was used as electron donor in BESs with biotic anode, whereas a direct current power supply was used as energy source in BESs with abiotic anode. The nitrogen removal efficiency increased from 18.1% to 43.0% when the voltage supplied to the BES with abiotic anode increased from 0.7 V to 0.9 V, whereas no higher removal efficiency was obtained at a higher supplied voltage (1.1 V). The highest efficiency (78.0%) of autotrophic nitrogen removal was achieved when electron transfer from the biotic anode chamber of BESs was used. Unexpectedly, control of the cathode potential did not enhance nitrate removal in BESs with biotic anode. Special attention was paid to elucidate the differences of bacterial communities catalysing autotrophic denitrification in the biocathodes of BESs with abiotic and biotic anodes. Data from denaturing gradient gel electrophoresis and phylogenetic analysis suggested that denitrification in BESs with abiotic anode could be attributed to Nitratireductor sp., Shinella sp., and Dyella sp., whereas the dominant bacterial denitrifiers in BESs with biotic anode were found to be Pseudomonas sp., Curtobacterium sp., and Aeromonas sp. These results implied that biocathodes of BESs with biotic anode are more efficient than those of BESs with abiotic anode for nitrate removal from nitrate-contaminated water in practical applications.
DOI: 10.1016/j.scriptamat.2016.08.036
2017
Cited 83 times
Atomistic investigations of κ-carbide precipitation in austenitic Fe-Mn-Al-C lightweight steels and the effect of Mo addition
The effect of Mo addition on precipitation behavior of κ-(Fe,Mn)3AlC during aging in austenitic Fe-Mn-Al-C lightweight steels was investigated. First-principles calculations indicate that substitution of Fe or Mn by Mo in κ-carbide is energetically unfavorable in the respect to formation energy, and it, moreover, increases strain energy contribution to interfacial energy between austenite matrix and κ-carbide. Atom probe tomography (APT) and transmission electron microscopy (TEM) analysis showed the results consistent with the calculations, i.e., Mo didn't partition into κ-carbide and delayed κ-carbide precipitation. Finally, nanoindentation experiments presented that Mo addition changed the aging hardening behavior, corresponding to κ-carbide precipitation behavior.
DOI: 10.1093/scan/nsu015
2014
Cited 81 times
Emotional arousal amplifies the effects of biased competition in the brain
The arousal-biased competition model predicts that arousal increases the gain on neural competition between stimuli representations. Thus, the model predicts that arousal simultaneously enhances processing of salient stimuli and impairs processing of relatively less-salient stimuli. We tested this model with a simple dot-probe task. On each trial, participants were simultaneously exposed to one face image as a salient cue stimulus and one place image as a non-salient stimulus. A border around the face cue location further increased its bottom-up saliency. Before these visual stimuli were shown, one of two tones played: one that predicted a shock (increasing arousal) or one that did not. An arousal-by-saliency interaction in category-specific brain regions (fusiform face area for salient faces and parahippocampal place area for non-salient places) indicated that brain activation associated with processing the salient stimulus was enhanced under arousal whereas activation associated with processing the non-salient stimulus was suppressed under arousal. This is the first functional magnetic resonance imaging study to demonstrate that arousal can enhance information processing for prioritized stimuli while simultaneously impairing processing of non-prioritized stimuli. Thus, it goes beyond previous research to show that arousal does not uniformly enhance perceptual processing, but instead does so selectively in ways that optimizes attention to highly salient stimuli.
DOI: 10.1016/j.apcatb.2020.119627
2021
Cited 73 times
Highly monodisperse sub-nanometer and nanometer Ru particles confined in alkali-exchanged zeolite Y for ammonia decomposition
Nanometer- and sub-nanometer-sized Ru particles were deposited on four different alkali-exchanged zeolite Y supports (H-Y, Na-Y, K-Y, and Rb-Y) by an ion-exchange method followed by a calcination treatment under vacuum. The average particle size of the Ru-based catalysts (Ru/M-Y: M = H, Na, K, and Rb) was approximately 1 nm, with the majority of Ru particles being highly monodisperse with a size in the sub-nanometer range. The oxygen-deficient environment during calcination and the well-defined repeated pore structure of zeolite are thought to have strongly affected the formation of Ru particles by restraining particle growth inside the upper/sodalite cages of the zeolite Y matrix. X-ray absorption spectroscopic analysis revealed that the Ru particles were highly reducible at low temperatures and were low coordinated with short RuO bonds. The effect of surface acidity on the catalytic activity of Ru/M for ammonia decomposition was investigated. Ammonia temperature-programmed desorption analysis suggested that the acidity of the alkali-exchanged zeolite Y increased (H > Na > K > Rb) with an increase in the electronegativity of the alkali cation. Among all the catalysts, H-Y exhibited the highest acidity because of the presence of strong Brønsted acid sites. The catalytic activities of the Ru/M-Y catalysts for ammonia decomposition in the gas phase decreased in the order of Ru/Rb-Y > Ru/K-Y > Ru/Na-Y > Ru/H-Y, that is, the lower the acidity, the higher is the catalytic activity. This was correlated to increased electron density of the surrounding Ru active sites, which likely facilitated nitrogen desorption from the catalyst surface. Finally, the surface intermediates formed under ammonia decomposition conditions were identified by in situ diffuse reflectance infrared Fourier transform spectroscopy. NH/NH2 surface intermediates were identified in the presence of Ru with weaker NH bonds in the case of Ru/Rb-Y compared to the case of Ru/H-Y. Overall, the high catalytic activity of the Ru/Rb-Y catalyst for ammonia decomposition was mainly because of the high basicity of the Rb-Y zeolite and the confined nanometer- and sub-nanometer-sized Ru particles, which led to a high Ru dispersion, open pore structure of the zeolite, and strong metal to support interaction between the Ru active sites and the Rb-Y zeolite support.
DOI: 10.3390/met8080653
2018
Cited 68 times
Molybdenum Effects on Pitting Corrosion Resistance of FeCrMnMoNC Austenitic Stainless Steels
For Fe-based 18Cr10Mn0.4N0.5C(0–2.17)Mo (in wt %) austenitic stainless steels, effects of Mo on pitting corrosion resistance and the improvement mechanism were investigated. Alloying Mo increased pitting and repassivation potentials and enhanced the passive film resistance by decreasing number of point defects in the film. In addition, Mo reduced critical dissolution rate of the alloys in acidified chloride solutions, and the alloy with higher Mo content could remain in the passive state in stronger acid. Thus, it was concluded that the alloying Mo enhanced pitting corrosion resistance of the alloys through increasing protectiveness of passive film and lowering pit growth rate.
DOI: 10.1016/j.biortech.2021.125240
2021
Cited 64 times
Anammox bacteria in treating ammonium rich wastewater: Recent perspective and appraisal
The discovery of anammox process has provided eco-friendly and low-cost means of treating ammonia rich wastewater with remarkable efficiency. Furthermore, recent studies have shown that the possibility of operating the anammox process under low temperatures and high organic matter contents broadening the application of the anammox process. However, short doubling time and extensive levels of sensitivity towards nutrients and environmental alterations such as salinity and temperature are the limitations in practical applications of the anammox process. This review article provides the recent yet comprehensive viewpoint on anammox bacteria and the key perspectives in applying them as an efficient strategy for wastewater treatment.
DOI: 10.1002/aenm.201804021
2019
Cited 60 times
Simple Bithiophene–Rhodanine‐Based Small Molecule Acceptor for Use in Additive‐Free Nonfullerene OPVs with Low Energy Loss of 0.51 eV
Abstract The introduction of rigid and extended ladder‐type fused‐ring cores, such as indacenodithiophene, has enabled the synthesis of a variety of nonfullerene small molecules for use as electron acceptors in high‐performance organic photovoltaic cells. Contrasting with recent trends, a very simple‐structured nonfullerene acceptor (NFA), T2‐ORH , consisting of a bithiophene core and octyl‐substituted rhodanine ends, is synthesized in two steps from inexpensive commercially available raw materials. Its relatively short π‐conjugation results in a wide bandgap and a blue‐shifted UV–vis absorption profile complementary to those of poly[4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b:4,5‐b′]dithiophene‐co‐3‐fluorothieno[3,4‐b]thiophene‐2‐carboxylate] (PTB7‐Th). Despite a sufficient offset between T2‐ORH and PTB7‐Th, the lowest unoccupied molecular orbital (LUMO) energy level of T2‐ORH is still higher than the LUMOs of other NFAs (e.g., ITIC). Therefore, the PTB7‐Th: T2‐ORH blend film exhibits an efficiency of 9.33% with a high open‐circuit voltage of 1.07 V and a short‐circuit current of 14.72 mA cm −2 in an additive‐free single‐junction cell. Importantly, the optimized device displays a remarkably low energy loss of 0.51 eV, in which bimolecular and monomolecular charge recombination is effectively suppressed by solvent vapor annealing treatment. The blend film has a very smooth and homogeneous morphology, providing both vertical and parallel charge transport in the devices.
DOI: 10.1038/s41467-020-19681-1
2020
Cited 58 times
Genome-enabled discovery of anthraquinone biosynthesis in Senna tora
Senna tora is a widely used medicinal plant. Its health benefits have been attributed to the large quantity of anthraquinones, but how they are made in plants remains a mystery. To identify the genes responsible for plant anthraquinone biosynthesis, we reveal the genome sequence of S. tora at the chromosome level with 526 Mb (96%) assembled into 13 chromosomes. Comparison among related plant species shows that a chalcone synthase-like (CHS-L) gene family has lineage-specifically and rapidly expanded in S. tora. Combining genomics, transcriptomics, metabolomics, and biochemistry, we identify a CHS-L gene contributing to the biosynthesis of anthraquinones. The S. tora reference genome will accelerate the discovery of biologically active anthraquinone biosynthesis pathways in medicinal plants.
DOI: 10.1016/j.rser.2021.111562
2021
Cited 45 times
An efficient process for sustainable and scalable hydrogen production from green ammonia
This study comprehensively investigates hydrogen production from green ammonia reforming, including synthesis of catalysts, reactor development, process integration, and techno-economic analysis. In-house developed Ru/La–Al2O3 pellet catalyst having perovskite structure showed high catalytic activity of 2827 h−1 at 450 °C and stability over 6700 h at 550 °C, exceeding the performance of the majority of powder catalysts reported in the literature. A scalable 12-faceted reactor adopting the as-produced catalyst was designed to enhance heat transfer, producing over 66 L min−1 of hydrogen with state-of-the-art ammonia reforming efficiency of 83.6 %. Near-zero CO2 emission of hydrogen extraction from green ammonia was demonstrated by-product gas recirculation as a combustion heat source. A techno-economic assessment was conducted for system scales from 10 kW to 10 MW, demonstrating the effect of reduced minimum hydrogen selling prices from 7.03 USD kg−1 at small modular scales to 3.98 USD kg−1 at larger industrial scales. Sensitivity analyses indicate that hydrogen selling prices may reduce even further (up to 50 %). The suggested hydrogen production route from green NH3 demonstrates superior CO2 reduction ranging from 78 % to 95 % in kg CO2 (kg H2)−1 compared to biomass gasification and steam methane reforming. These findings can be used as a basis for following economic and policy studies to further validate the effectiveness of the suggested system and process for H2 production from NH3.
DOI: 10.1016/j.jwpe.2021.102078
2021
Cited 39 times
Sulfate radicals based heterogeneous peroxymonosulfate system catalyzed by CuO-Fe3O4-Biochar nanocomposite for bisphenol A degradation
Magnetic CuO-Fe3O4-Biochar (CuO-Fe3O4-BC) nanoparticles were successfully synthesized by two steps of coprecipitation and calcination and were characterized as a heterogeneous catalyst to activate peroxymonosulfate for bisphenol A (BPA) degradation. The reaction process and mechanism of heterogeneous catalyst adsorption and synergistic catalytic oxidation for the removal of BPA in CuO-Fe3O4-BC/PMS system were extensively evaluated in view of the practical applications. Results indicated that the addition of CuO achieved a high removal efficiency of BPA in a wide pH range. BPA removal efficiency reached 100 % in 30 min by using 2.0 g/L CuO-Fe3O4-BC and 5 mM PMS at a pH of 9.0, and SO4− played an essential role in the degradation process. The synergistic effect of copper ions and iron ions accelerated the circulation of Fe (II)/Fe (III) and Cu (I)/Cu (II), which improved the electron transfer on the catalyst surface and increased the free radical generation rate. CuO, Fe3O4 and BC achieved a synergistic effect between adsorption and catalysis. The stability and reusability of CuO-Fe3O4-BC/PMS system offer an approach in organic pollutant wastewater treatment since it has great advantages of high removal efficiency, conducting under neutral conditions, energy-saving and avoiding the common issues in traditional Fenton reactions.
DOI: 10.1016/j.scitotenv.2022.160494
2023
Cited 11 times
Long-term adaptation of two anammox granules with different ratios of Candidatus Brocadia and Candidatus Jettenia under increasing salinity and their application to treat saline wastewater
Nitrogen removal in saline wastewater is a challenge of the anaerobic ammonium oxidation (anammox) process, which is dominated by freshwater anammox bacteria (FAB). Candidatus Brocadia and Candidatus Jettenia, the most widely used FABs, have been separately applied and evaluated for their ability to treat saline wastewater. To understand the effect of salinity on nitrogen removal capability when they present together in an anammox granule, we compared two anammox granules: GRN1 was evenly dominated by Ca. Brocadia (42 %) and Ca. Jettenia (43 %), while GRN2 was dominated with mostly Ca. Brocadia (90 %) and a small amount of Ca. Jettenia (1 %). Each granule was inoculated into a continuous column reactor to treat artificial wastewater containing 150 mg NH4+-N/L and 150 mg NO2--N/L under increasing saline conditions for 250 days. GRN1 showed superior and more stable nitrogen removal than GRN2 under saline conditions of up to 15 g NaCl/L. Under high-saline conditions, both the granules' sizes decreased (larger GRN1 than GRN2 in initial). The mass percent of Na salt increased (more in GRN2) and mineral contents decreased more in GRN1. High-throughput sequencing for microbial community analysis showed that Planctomycetes in GRN1 (85 %) and GRN2 (92 %) decreased to 14 % and 12 %, respectively. The ratio of Ca. Brocadia and Ca. Jettenia in GRN1 changed to 37 % and 63 %, respectively, whereas the ratio in GRN2 (99 % and 1 %, respectively) did not change. Both salt-adapted granules were applied to the two-stage partial nitritation and anammox (PN/A) process to treat high strength ammonium (400 mg/L) wastewater under high saline condition (15 g NaCl/L). The PN/A process containing GRN1 showed more stable nitrogen removal performance during approximately 100 days of operation. These results suggest that the anammox granules evenly dominated by two FABs, Ca. Brocadia and Ca. Jettenia, would be advantageous to treat high-strength NH4+ wastewater under high-saline conditions.
DOI: 10.3389/fpls.2023.1092584
2023
Cited 11 times
Digitalizing breeding in plants: A new trend of next-generation breeding based on genomic prediction
As the world's population grows and food needs diversification, the demand for cereals and horticultural crops with beneficial traits increases. In order to meet a variety of demands, suitable cultivars and innovative breeding methods need to be developed. Breeding methods have changed over time following the advance of genetics. With the advent of new sequencing technology in the early 21st century, predictive breeding, such as genomic selection (GS), emerged when large-scale genomic information became available. GS shows good predictive ability for the selection of individuals with traits of interest even for quantitative traits by using various types of the whole genome-scanning markers, breaking away from the limitations of marker-assisted selection (MAS). In the current review, we briefly describe the history of breeding techniques, each breeding method, various statistical models applied to GS and methods to increase the GS efficiency. Consequently, we intend to propose and define the term digital breeding through this review article. Digital breeding is to develop a predictive breeding methods such as GS at a higher level, aiming to minimize human intervention by automatically proceeding breeding design, propagating breeding populations, and to make selections in consideration of various environments, climates, and topography during the breeding process. We also classified the phases of digital breeding based on the technologies and methods applied to each phase. This review paper will provide an understanding and a direction for the final evolution of plant breeding in the future.
DOI: 10.1016/j.biortech.2023.128582
2023
Cited 9 times
Biofuel production from Euglena: Current status and techno-economic perspectives
Sustainable aviation fuels (SAFs) can contribute reduce greenhouse gas emissions compared to conventional fuel. With the increasing SAFs demand, various generations of resources have been shifted from the 1st generation (oil crops), the 2nd generation (agricultural waste), to the 3rd generation (microalgae). Microalgae are the most suitable feedstock for jet biofuel production than other resources because of their productivity and capability to capture carbon dioxide. However, microalgae-based biofuel has a limitation of high freezing point. Recently, a jet biofuel derived from Euglena wax ester has been paying attention due to its low freezing point. Challenges still remain to enhance production yields in both upstream and downstream processes. Studies on downstream processes as well as techno-economic analysis on biofuel production using Euglena are highly limited to date. Economic aspects for the biofuel production will be ensured via valorization of industrial byproducts such as food wastes.
DOI: 10.1016/j.bpsc.2023.04.008
2024
Brain Similarity as a Protective Factor in the Longitudinal Pathway Linking Household Chaos, Parenting, and Substance Use
Socioecological factors such as family environment and parenting behaviors contribute to the development of substance use. While biobehavioral synchrony has been suggested as the foundation for resilience that can modulate environmental effects on development, the role of brain similarity that attenuates deleterious effects of environmental contexts has not been clearly understood. We tested whether parent-adolescent neural similarity-the level of pattern similarity between parent-adolescent functional brain connectivity representing the level of attunement within each dyad-moderates the longitudinal pathways in which household chaos (a stressor) predicts adolescent substance use directly and indirectly via parental monitoring.In a sample of 70 parent-adolescent dyads, similarity in resting-state brain activity was identified using multipattern connectivity similarity estimation. Adolescents and parents reported on household chaos and parental monitoring, and adolescent substance use was assessed at a 1-year follow-up.The moderated mediation model indicated that for adolescents with low neural similarity, but not high neural similarity, greater household chaos predicted higher substance use over time directly and indirectly via lower parental monitoring. Our data also indicated differential susceptibility in the overall association between household chaos and substance use: Adolescents with low neural similarity exhibited high substance use under high household chaos but low substance use under low household chaos.Neural similarity acts as a protective factor such that the detrimental effects of suboptimal family environment and parenting behaviors on the development of adolescent health risk behaviors may be attenuated by neural similarity within parent-adolescent bonds.
DOI: 10.3390/ma17051178
2024
Deciphering Hydrogen Embrittlement Mechanisms in Ti6Al4V Alloy: Role of Solute Hydrogen and Hydride Phase
Ti6Al4V (Ti64) is a versatile material, finding applications in a wide range of industries due to its unique properties. However, hydrogen embrittlement (HE) poses a challenge in hydrogen-rich environments, leading to a notable reduction in strength and ductility. This study investigates the complex interplay of solute hydrogen (SH) and hydride phase (HP) formation in Ti64 by employing two different current densities during the charging process. Nanoindentation measurements reveal distinct micro-mechanical behavior in base metal, SH, and HP, providing crucial insights into HE mechanisms affecting macro-mechanical behavior. The fractography and microstructural analysis elucidate the role of SH and HP in hydrogen-assisted cracking behaviors. The presence of SH heightens intergranular cracking tendencies. In contrast, the increased volume of HP provides sites for crack initiation and propagation, resulting in a two-layer brittle fracture pattern. The current study contributes to a comprehensive understanding of HE in Ti6Al4V, essential for developing hydrogen-resistant materials.
DOI: 10.1021/np030384h
2004
Cited 123 times
Periconicins, Two New Fusicoccane Diterpenes Produced by an Endophytic Fungus <i>Periconia</i> sp. with Antibacterial Activity
Two new fusicoccane diterpenes, named periconicins A (1) and B (2), with antibacterial activities have been isolated by bioassay-guided fractionation from an endophytic fungus Periconia sp., collected from small branches of Taxus cuspidata. The structures of the new compounds were determined by combined spectroscopic methods.
DOI: 10.1016/j.scriptamat.2007.09.029
2008
Cited 111 times
Effects of nitrogen on deformation-induced martensitic transformation in metastable austenitic Fe–18Cr–10Mn–N steels
The effects of nitrogen content on deformation-induced martensitic transformation (DIMT) in Fe–18Cr–10Mn–N alloys were investigated. During tensile deformation, the stress–strain response was changed at different transient strains (ε ≅ 0.19–0.22) depending on the nitrogen content. At the beginning of the deformation, a γ → ε martensitic transformation occurred, whereas the formation of α′-martensite was predominant after transient strain. Increasing the nitrogen content caused the transient strain for DIMT to shift to higher strain and, finally, DIMT did not occur when nitrogen content was above 0.5 wt.%.
DOI: 10.1016/j.biortech.2012.04.078
2012
Cited 82 times
Electricity generation and microbial community in a submerged-exchangeable microbial fuel cell system for low-strength domestic wastewater treatment
A submerged type microbial fuel cell (MFC) system, which consisted of six readily exchangeable air-cathode MFCs, was evaluated for continuous treatment of low-strength domestic wastewater. When supplied with synthetic wastewater (COD 100 mg/L), the system showed increasing maximum power densities from 191 to 754 mW/m2 as COD loading rates increased (0.20-0.40 kg/m3/day). COD removal efficiencies decreased with increased COD loading rates but the effluent COD concentrations met the relevant effluent quality standard (CODMn 20 mg/L) at all conditions. The system was then operated with domestic wastewater (c.a. 100 mg COD/L) at 0.32 and 0.43 kg/m3/day. The system showed much lower power densities (116-149 mW/m2) at both loading rates, compared to synthetic wastewater. Anodic microbial communities were completely different when the wastewater type was changed. These results suggest that the newly developed MFC system could be applied to treat low-strength domestic wastewater without requiring any additional organic removal stage.
DOI: 10.1037/a0020222
2011
Cited 73 times
How does context affect assessments of facial emotion? The role of culture and age.
People from Asian cultures are more influenced by context in their visual processing than people from Western cultures. In this study, we examined how these cultural differences in context processing affect how people interpret facial emotions. We found that younger Koreans were more influenced than younger Americans by emotional background pictures when rating the emotion of a central face, especially those younger Koreans with low self-rated stress. In contrast, among older adults, neither Koreans nor Americans showed significant influences of context in their face emotion ratings. These findings suggest that cultural differences in reliance on context to interpret others' emotions depend on perceptual integration processes that decline with age, leading to fewer cultural differences in perception among older adults than among younger adults. Furthermore, when asked to recall the background pictures, younger participants recalled more negative pictures than positive pictures, whereas older participants recalled similar numbers of positive and negative pictures. These age differences in the valence of memory were consistent across culture.
DOI: 10.1105/tpc.114.125583
2014
Cited 66 times
Comparative Analysis of <i>Miscanthus</i> and <i>Saccharum</i> Reveals a Shared Whole-Genome Duplication but Different Evolutionary Fates
Multiple polyploidizations with divergent consequences in the grass subtribe Saccharinae provide a singular opportunity to study in situ adaptation of a genome to the duplicated state, heretofore known primarily from paleogenomics. We show that allopolyploidy in a common Miscanthus-Saccharum ancestor ∼3.8 to 4.6 million years ago closely coincides in time with their divergence from the Sorghum lineage. Subsequent Saccharum-specific autopolyploidy may have created pseudo-paralogous chromosome groups with random pairing within a group but infrequent pairing between groups. High chromosome number may reduce differentiation among Saccharum pseudo-paralogs by increasing opportunities for recombinations, with the lower chromosome numbers of Miscanthus favoring the return to disomic inheritance. The widespread tendency of plant chromosome numbers to recursively return to a narrow range following genome duplication appears to be occurring now in Saccharum spontaneum based on rich polymorphism for chromosome number among genotypes, with past reductions indicated by condensations of two ancestral chromosomes in Miscanthus (now n = 19) and perhaps as many as 10 in the Narenga-Sclerostachya clade (n = 15).
DOI: 10.1021/acs.nanolett.5b04957
2016
Cited 66 times
Electrical and Thermoelectric Transport by Variable Range Hopping in Thin Black Phosphorus Devices
The moderate band gap of black phosphorus (BP) in the range of 0.3–2 eV, along a high mobility of a few hundred cm2 V–1 s–1 provides a bridge between the gapless graphene and relatively low-mobility transition metal dichalcogenides. Here, we study the mechanism of electrical and thermoelectric transport in 10–30 nm thick BP devices by measurements of electrical conductance and thermopower (S) with various temperatures (T) and gate-electric fields. The T dependences of S and the sheet conductance (σ□) of the BP devices show behaviors of T1/3 and exp[−(1/T)1/3], respectively, where S reaches ∼0.4 mV/K near room T. This result indicates that two-dimensional (2D) Mott’s variable range hopping (VRH) is a dominant mechanism in the thermoelectric and electrical transport in our examined thin BP devices. We consider the origin of the 2D Mott’s VRH transport in our BPs as trapped charges at the surface of the underlying SiO2 based on the analysis with observed multiple quantum dots.
DOI: 10.1007/s00449-014-1246-x
2014
Cited 64 times
Power densities and microbial communities of brewery wastewater-fed microbial fuel cells according to the initial substrates
DOI: 10.1080/10407782.2013.831695
2013
Cited 63 times
Computation of the Natural Convection of Nanofluid in a Square Cavity with Homogeneous and Nonhomogeneous Models
Abstract A numerical study of a laminar natural convection of the CuO-water nanofluid in a square cavity using homogeneous and nonhomogeneous models is presented. All the governing equations including the volume fraction equation are discretized on a cell-centered, nonuniform grid employing the finite-volume method with a primitive variable formulation. Calculations are performed over a range of Rayleigh numbers (Raf = 104–107) and volume fractions of the nanoparticle (0.01 ≤ Φ ≤ 0.1). From the computed results, it is shown that both the homogeneous and nonhomogeneous models predict the deterioration of the natural convection heat transfer well with an increase of the volume fraction of nanoparticle at the same Rayleigh number, which was observed in the previous experimental studies. It is also shown that the differences in the computed results of the average Nusselt number at the wall between the homogeneous and nonhomogeneous models are very small, and this indicates that the slip mechanism of the Brown diffusion and thermophoresis effects are negligible in the laminar natural convection of the nanofluid. The degradation of the heat transfer with an increase of the volume fraction of the nanoparticle in the natural convection of nanofluid is due to the increase of the viscosity and the decrease of the thermal expansion coefficient and the specific heat. It is clarified in the present study that the previous controversies between the numerical and experimental studies are owing to the different definitions of the Nusselt number. Acknowledgments This study has been supported by the Nuclear Research and Development Program of the Ministry of Education, Science and Technology of Korea.
DOI: 10.1016/j.neuroimage.2017.02.025
2017
Cited 62 times
Higher locus coeruleus MRI contrast is associated with lower parasympathetic influence over heart rate variability
The locus coeruleus (LC) is a key node of the sympathetic nervous system and suppresses parasympathetic activity that would otherwise increase heart rate variability. In the current study, we examined whether LC-MRI contrast reflecting neuromelanin accumulation in the LC was associated with high-frequency heart rate variability (HF-HRV), a measure reflecting parasympathetic influences on the heart. Recent evidence indicates that neuromelanin, a byproduct of catecholamine metabolism, accumulates in the LC through young and mid adulthood, suggesting that LC-MRI contrast may be a useful biomarker of individual differences in habitual LC activation. We found that, across younger and older adults, greater LC-MRI contrast was negatively associated with HF-HRV during fear conditioning and spatial detection tasks. This correlation was not accounted for by individual differences in age or anxiety. These findings indicate that individual differences in LC structure relate to key cardiovascular parameters.
DOI: 10.1016/j.net.2016.08.004
2016
Cited 61 times
Overall System Description and Safety Characteristics of Prototype Gen IV Sodium Cooled Fast Reactor in Korea
The Prototype Gen IV sodium cooled fast reactor (PGSFR) has been developed for the last 4 years, fulfilling the technology demonstration of the burning capability of transuranic elements included in light water reactor spent nuclear fuel. The PGSFR design has been focused on the robustness of safety systems by enhancing inherent safety characteristics of metal fuel and strengthening passive safety features using natural circulation and thermal expansion. The preliminary safety information document as a major outcome of the first design phase of PGSFR development was issued at the end of 2015. The project entered the second design phase at the beginning of 2016. This paper summarizes the overall structures, systems, and components of nuclear steam supply system and safety characteristics of the PGSFR. The research and development activities to demonstrate the safety performance are also briefly introduced in the paper.
DOI: 10.1016/j.neuroimage.2017.02.078
2017
Cited 61 times
Families that fire together smile together: Resting state connectome similarity and daily emotional synchrony in parent-child dyads
Despite emerging evidence suggesting a biological basis to our social tiles, our understanding of the neural processes which link two minds is unknown. We implemented a novel approach, which included connectome similarity analysis using resting state intrinsic networks of parent-child dyads as well as daily diaries measured across 14 days. Intrinsic resting-state networks for both parents and their adolescent child were identified using independent component analysis (ICA). Results indicate that parents and children who had more similar RSN connectome also had more similar day-to-day emotional synchrony. Furthermore, dyadic RSN connectome similarity was associated with children's emotional competence, suggesting that being neurally in-tune with their parents confers emotional benefits. We provide the first evidence that dyadic RSN similarity is associated with emotional synchrony in what is often our first and most essential social bond, the parent-child relationship.
DOI: 10.1111/nph.13689
2015
Cited 56 times
Comparative genomic de‐convolution of the cotton genome revealed a decaploid ancestor and widespread chromosomal fractionation
The 'apparently' simple genomes of many angiosperms mask complex evolutionary histories. The reference genome sequence for cotton (Gossypium spp.) revealed a ploidy change of a complexity unprecedented to date, indeed that could not be distinguished as to its exact dosage. Herein, by developing several comparative, computational and statistical approaches, we revealed a 5× multiplication in the cotton lineage of an ancestral genome common to cotton and cacao, and proposed evolutionary models to show how such a decaploid ancestor formed. The c. 70% gene loss necessary to bring the ancestral decaploid to its current gene count appears to fit an approximate geometrical model; that is, although many genes may be lost by single-gene deletion events, some may be lost in groups of consecutive genes. Gene loss following cotton decaploidy has largely just reduced gene copy numbers of some homologous groups. We designed a novel approach to deconvolute layers of chromosome homology, providing definitive information on gene orthology and paralogy across broad evolutionary distances, both of fundamental value and serving as an important platform to support further studies in and beyond cotton and genomics communities.
DOI: 10.1016/j.biortech.2017.02.101
2017
Cited 56 times
Response of microbial community structure to pre-acclimation strategies in microbial fuel cells for domestic wastewater treatment
Microbial community structures and performance of air-cathode microbial fuel cells (MFCs) inoculated with activated sludge from domestic wastewater were investigated to evaluate the effects of three substrate pre-acclimation strategies: 1, serial pre-acclimation with acetate and glucose before supplying domestic wastewater; 2, one step pre-acclimation with acetate before supplying domestic wastewater; and 3, direct supply of domestic wastewater without any pre-acclimation. Strategy 1 showed much higher current generation (1.4mA) and Coulombic efficiency (33.5%) than strategies 2 (0.7mA and 9.4%) and 3 (0.9mA and 10.3%). Pyrosequencing showed that microbial communities were significantly affected by pre-acclimation strategy. Although Proteobacteria was the dominant phylum with all strategies, Actinobacteria was abundant when MFCs were pre-acclimated with glucose after acetate. Not only anode-respiring bacteria (ARB) in the genus Geobacter but also non-ARB belonging to the family Anaerolinaceae seemed to play important roles in air-cathode MFCs to produce electricity from domestic wastewater.
DOI: 10.3389/fimmu.2019.00944
2019
Cited 55 times
Pyruvate Dehydrogenase Kinase Is a Metabolic Checkpoint for Polarization of Macrophages to the M1 Phenotype
Metabolic reprogramming during macrophage polarization supports the effector functions of these cells in health and disease. Here, we demonstrate that pyruvate dehydrogenase kinase (PDK), which inhibits the pyruvate dehydrogenase-mediated conversion of cytosolic pyruvate to mitochondrial acetyl-CoA, functions as a metabolic checkpoint in M1 macrophages. Polarization was not prevented by PDK2 or PDK4 deletion but was fully prevented by the combined deletion of PDK2 and PDK4; this lack of polarization was correlated with improved mitochondrial respiration and rewiring of metabolic breaks that are characterized by increased glycolytic intermediates and reduced metabolites in the TCA cycle. Genetic deletion or pharmacological inhibition of PDK2/4 prevents polarization of macrophages to the M1 phenotype in response to inflammatory stimuli (lipopolysaccharide plus IFN-γ). Transplantation of PDK2/4-deficient bone marrow into irradiated wild-type mice to produce mice with PDK2/4-deficient myeloid cells prevented M1 polarization, reduced obesity-associated insulin resistance, and ameliorated adipose tissue inflammation. A novel, pharmacological PDK inhibitor, KPLH1130, improved high-fat diet-induced insulin resistance; this was correlated with a reduction in the levels of pro-inflammatory markers and improved mitochondrial function. These studies identify PDK2/4 as a metabolic checkpoint for M1 phenotype polarization of macrophages, which could potentially be exploited as a novel therapeutic target for obesity-associated metabolic disorders and other inflammatory conditions.
DOI: 10.1007/s00429-017-1519-7
2017
Cited 54 times
Brain structural concomitants of resting state heart rate variability in the young and old: evidence from two independent samples
Previous research has shown associations between brain structure and resting state high-frequency heart rate variability (HF HRV). Age affects both brain structure and HF HRV. Therefore, we sought to examine the relationship between brain structure and HF HRV as a function of age. Data from two independent studies were used for the present analysis. Study 1 included 19 older adults (10 males, age range 62-78 years) and 19 younger adults (12 males, age range 19-37). Study 2 included 23 older adults (12 males; age range 55-75) and 27 younger adults (17 males; age range 18-34). The root-mean-square of successive R-R-interval differences (RMSSD) from ECG recordings was used as time-domain measure of HF HRV. MRI scans were performed on a 3.0-T Siemens Magnetom Trio scanner. Cortical reconstruction and volumetric segmentation were performed with the Freesurfer image analysis suite, including 12 regions as regions of interests (ROI). Zero-order and partial correlations were used to assess the correlation of RMSSD with cortical thickness in selected ROIs. Lateral orbitofrontal cortex (OFC) cortical thickness was significantly associated with RMSSD. Further, both studies, in line with previous research, showed correlations between RMSSD and anterior cingulate cortex (ACC) cortical thickness. Meta-analysis on adjusted correlation coefficients from individual studies confirmed an association of RMSSD with the left rostral ACC and the left lateral OFC. Future longitudinal studies are necessary to trace individual trajectories in the association of HRV and brain structure across aging.
DOI: 10.1016/j.corsci.2019.01.001
2019
Cited 54 times
Understanding the relation between pitting corrosion resistance and phase fraction of S32101 duplex stainless steel
The relation between phase fraction and pitting corrosion resistance of S32101 duplex stainless steel was interpreted by considering the stable and metastable pitting potential and galvanic corrosion rate of the duplex-phased matrix. As the ferrite fraction increased, the potential for the stable pitting corrosion was linearly decreased which was found to be closely related to the increase in the galvanic corrosion rate between the two constituent phases. It was also revealed that the pit propagation rate was more important than the pit initiation probability in determining the overall pitting corrosion resistance of the S32101 duplex stainless steel.
DOI: 10.1038/s41598-019-51586-y
2019
Cited 52 times
Direct observation of dislocation plasticity in high-Mn lightweight steel by in-situ TEM
Abstract To gain the fundamental understanding of deformation mechanisms in an aluminum-containing austenitic high-Mn steel (Fe-32Mn-8.9Al-0.78 C (wt.%)), in-situ straining transmission electron microscopy (TEM) analysis is conducted. The in-situ observation during the deformation demonstrates that the plastic deformation is accommodated by the pronounced planar dislocation gliding followed by the formation of slip bands (SBs) and highly dense dislocation walls (HDDWs). Experimental evidences of the glide plane softening can be obtained from the interaction between the gliding perfect dislocations and the L’1 2 ordered precipitates in the austenite matrix. Furthermore, the observation of the localized cross-slip of dislocations at the slip band intersections enables to understand why slip bands are extensively developed without mutual obstructions between the slip bands. The enhanced strain hardening rate of the aluminum-containing austenitic high-Mn steels can be attributed to the pronounced planar dislocation glides followed by formation of extensive slip band which prevent premature failure by suppressing strain localization.
DOI: 10.1039/d0ta00947d
2020
Cited 42 times
Non-halogenated solvent-processed ternary-blend solar cells <i>via</i> alkyl-side-chain engineering of a non-fullerene acceptor and their application in large-area devices
Ternary-blend organic solar cells based on a novel asymmetric non-fullerene acceptor (T2-OEHRH) processed from a non-halogenated solvent exhibit impressive PCEs of 12.10% and 9.32% in small- and large-area devices, respectively.
DOI: 10.1038/s41545-021-00122-5
2021
Cited 36 times
A twilight for the complete nitrogen removal via synergistic partial-denitrification, anammox, and DNRA process
Abstract The prolonged start-up time and low total nitrogen removal of anammox hinder its full-scale application. Herein, application of nano-zerovalent iron and low strength magnetic field in sole and in combination to abbreviate the start-up period and long-term process stability of anammox was carried out. The reactor’s anammox start-up with the only magnetic field (R3) was 34 days, saving 43.3% time compared with the control. The increase of nitrogen removal efficiency over the control was 43.7% during the start-up period. However, the reactor with the coupled treatment of nano-zerovalent iron and magnetic field (R4) was more stable with higher nitrogen removal efficiency (80%) at high nitrogen loading (5.28 kg/m 3 /d). Anammox gene copy number in R4 was highest after 180 days of culture, followed by nano-zerovalent iron (R2) and R3 reactor. The functional genes of denitrifying bacteria (nirK and nirS) were also identified in all reactors with higher copy numbers in R2, followed by R4 and R3. Furthermore, high throughput analysis showed that the Thauera performing partial denitrification, Ignavibacterium performing dissimilatory nitrate reduction to ammonium or nitrite were also present in all reactors, more abundant in R4, confirming that the higher nitrogen removal efficiency in R4 was attributed to the synergistic relationship of other nitrogenous genera with anammox. The higher abundance of PD and DNRA in the reactor with the coupled treatment of nano-zero valent iron and magnetic field, achieved in this research, opens the opportunity of complete nitrogen removal via synergistic partial-denitrification, anammox, and DNRA (SPDAD) process.
DOI: 10.1016/j.scitotenv.2020.144231
2021
Cited 34 times
Understanding complete ammonium removal mechanism in single-chamber microbial fuel cells based on microbial ecology
The removal of organics and ammonium from domestic wastewater was successfully achieved by a flat-panel air-cathode microbial fuel cell (FA-MFC). To elucidate the reason for complete ammonium removal in the single-chamber MFCs, microbial communities were analyzed in biofilms on the surface of each anode, separator, and cathode of separator-electrode assemblies (SEAs). The spatial distribution of bacterial families related to the nitrogen cycle varied based on local conditions. Since oxygen diffusing from the air-cathode created a locally aerobic condition, ammonia-oxidizing bacteria (AOB) Nitrosomonadacea and nitrite-oxidizing bacteria (NOB) Nitrospiraceae were present near the cathode. NOB (~12.1%) was more abundant than AOB (~4.4%), suggesting that the nitrate produced by NOB may be reduced back to nitrite by heterotrophic denitrifiers such as Rhodocyclaceae (~21.7%) and Comamonadaceae (~5%) in the anoxic zone close to the NOB layer. Near that zone, the “nitrite loop” also substantially enriched two nitrite-reducing bacterial families: Ignavibacteriaceae (~18.1%), facultative heterotrophs, and Brocadiaceae (~11.2%), anaerobic ammonium oxidizing autotrophs. A larger inner area of biofilm contained abundant heterotrophic denitrifiers and fermentation bacteria. These results indicate that the large-surface SEA of FA-MFC allows counter-diffusion between substrates and oxygen, resulting in interactions of bacteria involved in the nitrogen cycle for complete ammonium removal.
DOI: 10.1016/j.celrep.2022.110906
2022
Cited 23 times
Neural circuit pathology driven by Shank3 mutation disrupts social behaviors
Dysfunctional sociability is a core symptom in autism spectrum disorder (ASD) that may arise from neural-network dysconnectivity between multiple brain regions. However, pathogenic neural-network mechanisms underlying social dysfunction are largely unknown. Here, we demonstrate that circuit-selective mutation (ctMUT) of ASD-risk Shank3 gene within a unidirectional projection from the prefrontal cortex to the basolateral amygdala alters spine morphology and excitatory-inhibitory balance of the circuit. Shank3 ctMUT mice show reduced sociability as well as elevated neural activity and its amplitude variability, which is consistent with the neuroimaging results from human ASD patients. Moreover, the circuit hyper-activity disrupts the temporal correlation of socially tuned neurons to the events of social interactions. Finally, optogenetic circuit activation in wild-type mice partially recapitulates the reduced sociability of Shank3 ctMUT mice, while circuit inhibition in Shank3 ctMUT mice partially rescues social behavior. Collectively, these results highlight a circuit-level pathogenic mechanism of Shank3 mutation that drives social dysfunction.
DOI: 10.1523/jneurosci.1865-21.2022
2022
Cited 21 times
Emotion Downregulation Targets Interoceptive Brain Regions While Emotion Upregulation Targets Other Affective Brain Regions
Researchers generally agree that when upregulating and downregulating emotion, control regions in the prefrontal cortex turn up or down activity in affect-generating brain areas. However, the "affective dial hypothesis" that turning up and down emotions produces opposite effects in the same affect-generating regions is untested. We tested this hypothesis by examining the overlap between the regions activated during upregulation and those deactivated during downregulation in 54 male and 51 female humans. We found that upregulation and downregulation both recruit regulatory regions, such as the inferior frontal gyrus and dorsal anterior cingulate gyrus, but act on distinct affect-generating regions. Upregulation increased activity in regions associated with emotional experience, such as the amygdala, anterior insula, striatum, and anterior cingulate gyrus as well as in regions associated with sympathetic vascular activity, such as periventricular white matter, while downregulation decreased activity in regions receiving interoceptive input, such as the posterior insula and postcentral gyrus. Nevertheless, participants' subjective sense of emotional intensity was associated with activity in overlapping brain regions (dorsal anterior cingulate, insula, thalamus, and frontal pole) across upregulation and downregulation. These findings indicate that upregulation and downregulation rely on overlapping brain regions to control and assess emotions but target different affect-generating brain regions.SIGNIFICANCE STATEMENT Many contexts require modulating one's own emotions. Identifying the brain areas implementing these regulatory processes should advance understanding emotional disorders and designing potential interventions. The emotion regulation field has an implicit assumption we call the affective dial hypothesis: both emotion upregulation and downregulation modulate the same emotion-generating brain areas. Countering the hypothesis, our findings indicate that up- and down-modulating emotions target different brain areas. Thus, the mechanisms underlying emotion regulation might differ more than previously appreciated for upregulation versus downregulation. In addition to their theoretical importance, these findings are critical for researchers attempting to target activity in particular brain regions during an emotion regulation intervention.
DOI: 10.1038/s41598-022-09579-x
2022
Cited 20 times
Insight into impact of sewage discharge on microbial dynamics and pathogenicity in river ecosystem
Direct sewage discharge could cause copious numbers of serious and irreversible harm to the environment. This study investigated the impacts of treated and raw sewage on the river ecosystem. Through our analysis, sewage carried various nutrients into the river, leading to changes in the microbial community in the river and reducing the diversity and richness of bacteria. The relative abundances of Hydrogenophaga, Thauera, Planctomyces, Zoogloea, and Pseudomonas boosted from 0.25, 0.01, 0.00, 0.05, and 0.08% to 3.33, 3.43, 0.02, 6.28, and 2.69%, before and after raw sewage discharge, respectively. The gene abundance of pathogenic bacteria significantly increased after raw sewage discharge. For instance, the gene abundance of Vibrio, Helicobacter, Tuberculosis, and Staphylococcus augmented from 4055, 3797, 13,545, 33 reads at Site-1 to 23,556, 13,163, 19,887, 734 reads at Site-2, respectively. In addition, according to the redundancy analysis (RDA), the infectious pathogens were positively related to the environmental parameters, in which COD showed the highest positive correlation with Mycobacterium tuberculosis. Additionally, river self-purification may contribute to improving water quality and reducing pathogenicity. The outcomes of this study showed that direct discharge brought pathogens and changed microbial community structure of the river.
DOI: 10.1016/j.dcn.2023.101218
2023
Cited 7 times
Negative impact of daily screen use on inhibitory control network in preadolescence: A two-year follow-up study
The COVID-19 pandemic has made an unprecedented shift in children's daily lives. Children are increasingly spending time with screens to learn and connect with others. As the online environment rapidly substitutes in-person experience, understanding children's neuropsychological trajectories associated with screen experiences is important. Previous findings suggest that excessive screen use can lead children to prefer more immediate rewards over delayed outcomes. We hypothesized that increased screen time delays a child's development of inhibitory control system in the brain (i.e., fronto-striatal circuitry). By analyzing neuropsychological data from 8324 children (9-11ys) from the ABCD Study, we found that children who had more screen time showed a higher reward orientation and weaker fronto-striatal connectivity. Importantly, we found that the daily screen exposure mediated the effect of reward sensitivity on the development of the inhibitory control system in the brain over a two year period. These findings suggest possible negative long-term impacts of increased daily screen time on children's neuropsychological development. The results further demonstrated that screen time influences dorsal striatum connectivity, which suggests that the effect of daily screen use is a habitual seeking behavior. The study provides neural and behavioral evidence for the negative impact of daily screen use on developing children.
DOI: 10.1016/j.tecto.2023.229817
2023
Cited 7 times
Correlation of paleoearthquake records at multiple sites along the southern Yangsan Fault, Korea: Insights into rupture scenarios of intraplate strike-slip earthquakes
The construction of spatiotemporal models of earthquake occurrence for intraplate areas is challenging due to the low deformation rates in these areas. In this study, we conducted paleoseismological investigations along the southern Yangsan Fault (SYF), a typical low-deformation-rate fault, on the Korean Peninsula. The SYF is distinct from the northern Yangsan Fault (NYF), and the boundary between them is located at the junction between the NNE-striking YF and another major structure, the NNW-striking Ulsan Fault (UF), which branches off from the YF. Paleoseismological trenches at four sites along the SYF indicate that this fault section has not ruptured during the Holocene, in contrast to the NYF and UF. In detail, surface ruptures along the studied section of the SYF occurred during three different time periods, as inferred from stratigraphy and radiocarbon dating: 74 to 49 ka at two sites, 39 to 35 ka at another site, and 28,000 cal yr BP (or 30 ka considering the OSL age) to 16 ka at all sites. These results suggest two alternative rupture scenarios for the timing of paleoearthquakes along the studied fault section during the Late Pleistocene: (1) full rupture along the entire studied section during each earthquake event, or (2) multiple partial ruptures along the two structurally distinguishable parts of the studied fault section, that is, the Wolsan–Miho and Inbo north–Inbo sections. We conclude that geometric discontinuities of the long-lived YF system in the Korean Peninsula intraplate region have played an important role in controlling recent spatiotemporal rupture behavior.
DOI: 10.1016/j.jwpe.2023.104615
2024
Optimization of two CSTRs using granular sludges dominated by Ca. Jettenia asiatica and Ca. Brocadia sinica
Two CSTRs using granules dominated by Ca. Jetteni asiatica (R1) and Ca. Brocadia sinica (R2) were operated depending on influent T-N concentrations and HRT. R1 achieved the highest NRR of 1.64 kgN/m3/day at HRT 8 h and T-N 600 mg/L, while R2 obtained the highest NRR of 2.05 kgN/m3/day at HRT 4 h and T-N 400 mg/L. The both reactors achieved high performance in high T-N concentration with the increasing of HRT in relatively short time. The sufficient T-N concentration and favorable short HRT were giving significant effects in promoting biomass increment and maintaining high removal in R1 and R2. In R1, granules larger than 2 mm accounted for over 60 %, while in R2 granules in the range of 1-2 mm comprised approximately 60 %. Granules in R1 were relatively harder and denser, and the surface of granules in R1 appeared rough, whereas the surface of granules in R2 seemed smoother. The abundance of anammox bacteria were much improved in both R1 and R2, operating under optimal operational conditions, showed significant improvement. The distribution of Ca. Brocadia sinica increased from 2.6 % to 42.0 % for R1 and from 9.1 %, to 90.5 % for R2, while there was little change in Ca. Jettenia asiatica. In this study, while the optimal HRT and nitrogen concentration as influent varied depending on the dominant anammox bacteria and granule characteristics in the inoculum, Ca. Brocadia sinica appears to play a significant role in nitrogen removal.
DOI: 10.1007/s11661-998-0332-6
2000
Cited 109 times
Crystallographic details of precipitates in Fe-22Cr-21Ni-6Mo-(N) superaustenitic stainless steels aged at 900 °C
DOI: 10.1016/s1359-6462(02)00477-3
2003
Cited 106 times
Effect of Cu, Cr and Ni on mechanical properties of 0.15 wt.% C TRIP-aided cold rolled steels
Cold-rolled steels based on 0.15C–1.5Mn–1.5Si–0.5Cu containing Cr or/and Ni were prepared, and intercritical annealing and isothermal treatment, were carried out. The addition of Cu or Cu+Ni resulted in a large increase of the retained austenite volume fraction as well as an improvement of elongation and the strength-ductility balance. However, the addition of Cr or Cu+Ni showed a dual-phase deformation behavior having higher tensile strength and lower elongation.
DOI: 10.1016/s0921-5093(03)00035-2
2004
Cited 103 times
Effects of volume fraction and stability of retained austenite on formability in a 0.1C–1.5Si–1.5Mn–0.5Cu TRIP-aided cold-rolled steel sheet
The effects of volume fraction and stability of retained austenite on formability of a 0.1C–1.5Si–1.5Mn–0.5Cu (hereafter all in wt.%) TRIP-aided cold-rolled steel sheet was investigated after various heat treatments (intercritical annealing and isothermal treatment). Tensile tests and limiting dome height (LDH) tests were conducted on the heat-treated sheet specimens, and the changes of retained austenite volume fraction as a function of tensile strain were measured using an X-ray diffractometer. The results showed a plausible relationship between formability and retained austenite parameters such as stability and initial volume fraction. The formability was improved with increasing volume fraction of retained austenite. However, when the volume fraction of retained austenite was same, the better formability was obtained in the specimens with the higher stability of retained austenite. This indicated that the strain-induced transformation of retained austenite to martensite could be stably progressed, thereby leading to the improvement of formability. Thus, the heat-treatment conditions should be established in consideration of the maximum volume fraction and high stability of retained austenite, and the optimal conditions were found to be intercritical annealing in the temperature range at which the austenite volume fraction was about 50%, followed by isothermal treatment at Ms temperature.
DOI: 10.1016/j.bmcl.2006.09.080
2007
Cited 88 times
Synthesis and structure–activity studies of antofine analogues as potential anticancer agents
Due to the profound cytotoxicities and interesting biochemical aspects, phenanthroindolizidine alkaloids have received an attention as potential therapeutic leads. To define the features of the molecule that are essential for cytotoxicity, we have synthesized and evaluated a series of phenanthroindolizidine alkaloid, antofine, analogues with different substituents on the phenanthrene ring. The systematic structure activity relationship studies elucidate the essential functional group requirement of phenanthrene ring, providing the basis for further development of phenanthroindolizidine alkaloids.
DOI: 10.1021/jo049820a
2004
Cited 82 times
Asymmetric Total Syntheses of (−)-Antofine and (−)-Cryptopleurine Using (<i>R</i>)-(<i>E</i>)-4-(Tributylstannyl)but-3-en-2-ol
The asymmetric total syntheses of the representative phenanthroindolizidine and phenanthroquinolizidine alkaloids, (−)-antofine and (−)-cryptopleurine, are described. An efficient synthetic pathway to the key intermediate 12, in enantiomerically pure form, was achieved by using a chiral building block (R)-9 and the Overman rearrangement with a total transfer of chirality. The problem of constructing the pyrrolidine and piperidine rings was successfully addressed, primarily by using a ring-closing metathesis reaction and a cross-metathesis reaction, respectively.
DOI: 10.1016/j.scriptamat.2009.03.018
2009
Cited 78 times
Effects of combined addition of carbon and nitrogen on pitting corrosion behavior of Fe–18Cr–10Mn alloys
The pitting corrosion resistance and passive film properties of Fe–18Cr–10Mn–(0.39–0.69)N–(0–0.38)C alloys were investigated. The combined addition of carbon and nitrogen enhanced the resistance against pitting corrosion of the alloys, which was attributed to an improvement in the protective ability of the passive film. Both passive film thickness and chromium content in the film were increased along with the sum of carbon and nitrogen content, which was confirmed by the galvanostatic reduction test, Mott–Schottky analysis and X-ray photoelectron spectroscopy measurement.
DOI: 10.1021/jo070668x
2007
Cited 75 times
Expedient Syntheses of Antofine and Cryptopleurine via Intramolecular 1,3-Dipolar Cycloaddition
The practical and expedient total syntheses of the representative phenanthroindolizidine and phenanthroquinolizidine alkaloids, antofine and cryptopleurine, are described. Construction of the pyrrolidine and piperidine ring of each alkaloid was achieved by using an intramolecular 1,3-dipolar cycloaddition of an azide onto an alkene and subsequent reduction of the resulting imine and aziridine.
DOI: 10.5516/net.2009.41.8.1025
2009
Cited 69 times
DEVELOPMENT OF A SUPERCRITICAL CO<sub>2</sub>BRAYTON ENERGY CONVERSION SYSTEM COUPLED WITH A SODIUM COOLED FAST REACTOR
Systematic research has been conducted by KAERI to develop a supercritical carbon dioxide Brayton cycle energy conversion system coupled with a sodium cooled fast reactor. For the development of the supercritical <TEX>$CO_2$</TEX> Brayton cycle ECS, KAERI researched four major fields, separately. For the system development, computer codes were developed to design and analyze the supercritical <TEX>$CO_2$</TEX> Brayton cycle ECS coupled with the KALIMER-600. Computer codes were developed to design and analyze the performance of the major components such as the turbomachinery and the high compactness PCHE heat exchanger. Three dimensional flow analysis was conducted to evaluate their performance. A new configuration for a PCHE heat exchanger was developed by using flow analysis, which showed a very small pressure loss compared with a previous PCHE while maintaining its heat transfer rate. Transient characteristics for the supercritical <TEX>$CO_2$</TEX> Brayton cycle coupled with KALIMER-600 were also analyzed using the developed computer codes. A Na-<TEX>$CO_2$</TEX> pressure boundary failure accident was analyzed with a computer code that included a developed model for the Na-<TEX>$CO_2$</TEX> chemical reaction phenomena. The MMS-LMR code was developed to analyze the system transient and control logic. On the basis of the code, the system behavior was analyzed when a turbine load was changed. This paper contains the current research overview of the supercritical <TEX>$CO_2$</TEX> Brayton cycle coupled to the KALIMER-600 as an alternative energy conversion system.
DOI: 10.4014/jmb.1103.03038
2011
Cited 59 times
Effects of Carbon and Nitrogen Sources on Fatty Acid Contents and Composition in the Green Microalga, Chlorella sp. 227
In order to investigate and generalize the effects of carbon and nitrogen sources on the growth of and lipid production in Chlorella sp. 227, several nutritional combinations consisting of different carbon and nitrogen sources and concentrations were given to the media for cultivation of Chlorella sp. 227, respectively. The growth rate and lipid content were affected largely by concentration rather than by sources. The maximum specific growth was negatively affected by low concentrations of carbon and nitrogen. There is a maximum allowable inorganic carbon concentration (less than 500~1,000 mM bicarbonate) in autotrophic culture, but the maximum lipid content per gram dry cell weight (g DCW) was little affected by the concentration of inorganic carbon within the concentration. The lipid content per g DCW was increased when the microalga was cultured with the addition of glucose and bicarbonate (mixotrophic) at a fixed nitrogen concentration and with the lowest nitrogen concentration (0.2 mM), relatively. Considering that lipid contents per g DCW increased in those conditions, it suggests that a high ratio of carbon to nitrogen in culture media promotes lipid accumulation in the cells. Interestingly, a significant increase of the oleic acid amount to total fatty acids was observed in those conditions. These results showed the possibility to induce lipid production of high quality and content per g DCW by modifying the cultivation conditions.
DOI: 10.1002/jcp.24243
2013
Cited 59 times
Barrier protective effects of rosmarinic acid on HMGB1‐induced inflammatory responses in vitro and in vivo
High mobility group box 1 (HMGB1) protein is a crucial cytokine that mediates response to infection, injury, and inflammation. Rosmarinic acid (RA) is an important component of the leaves of Perilla frutescens and has neuroprotective, anti-microbial, anti-oxidant, and anti-cancer effects but little is known of its effects on HMGB1-mediated inflammatory response. Here, we investigated this issue by monitoring the effects of RA on the lipopolysaccharide (LPS) or cecal ligation and puncture (CLP)-mediated release of HMGB1 and HMGB1-mediated modulation of inflammatory responses. RA potently inhibited the release of HMGB1 and down-regulated HMGB1-dependent inflammatory responses in human endothelial cells. RA also inhibited HMGB1-mediated hyperpermeability and leukocyte migration in mice. Furthermore, RA reduced CLP-induced HMGB1 release and sepsis-related mortality. Given these results, RA should be viewed as a candidate therapeutic agent for the treatment of various inflammatory diseases via inhibition of the HMGB1 signaling pathway.
DOI: 10.1016/j.msea.2011.06.025
2011
Cited 56 times
Correlation of austenite stability and ductile-to-brittle transition behavior of high-nitrogen 18Cr–10Mn austenitic steels
Ductile-to-brittle transition behavior of high-nitrogen 18Cr–10Mn austenitic steels containing different contents of Ni, Mo, Cu as well as nitrogen is discussed in terms of austenite stability and associated deformation-induced martensitic transformation (DIMT). Electron back-scattered diffraction and transmission electron microscopy analyses of cross-sectional area of the Charpy impact specimens fractured at −196 °C indicated that the brittle fracture planes were almost parallel to one of {1 1 1} slip planes and some metastable austenites near the fracture surface were transformed to α′-martensite by localized plastic deformation occurring during crack propagation. Quantitative evaluation of deformation-induced martensite together with characteristics of true stress–strain and load–displacement curves obtained from tensile and Charpy impact tests, respectively, supported that DIMT might take place in high-nitrogen austenitic steels with relatively low austenite stability. The occurrence of DIMT decreased low-temperature toughness and thus increased largely ductile-to-brittle transition temperature (DBTT), as compared to that predicted by empirical equations strongly depending on nitrogen content. As a result, the increased DBTT could be reasonably correlated with austenite stability against DIMT.
DOI: 10.1111/nph.12137
2013
Cited 55 times
Gene body methylation shows distinct patterns associated with different gene origins and duplication modes and has a heterogeneous relationship with gene expression in <i>Oryza sativa</i> (rice)
Summary Whole‐genome duplication ( WGD ) has been recurring and single‐gene duplication is also widespread in angiosperms. Recent whole‐genome DNA methylation maps indicate that gene body methylation (i.e. of coding regions) has a functional role. However, whether gene body methylation is related to gene origins and duplication modes has yet to be reported. In rice ( Oryza sativa ), we computed a body methylation level (proportion of methylated CpG within coding regions) for each gene in five tissues. Body methylation levels follow a bimodal distribution, but show distinct patterns associated with transposable element‐related genes; WGD , tandem, proximal and transposed duplicates; and singleton genes. For pairs of duplicated genes, divergence in body methylation levels increases with physical distance and synonymous ( K s) substitution rates, and WGD s show lower divergence than single‐gene duplications of similar K s levels. Intermediate body methylation tends to be associated with high levels of gene expression, whereas heavy body methylation is associated with lower levels of gene expression. The biological trends revealed here are consistent across five rice tissues, indicating that genes of different origins and duplication modes have distinct body methylation patterns, and body methylation has a heterogeneous relationship with gene expression and may be related to survivorship of duplicated genes.
DOI: 10.1007/s11661-012-1423-y
2012
Cited 54 times
Effect of Carbon Fraction on Stacking Fault Energy of Austenitic Stainless Steels
The effect of C fraction (C/N) on stacking fault energy (SFE) of austenitic Fe-18Cr-10Mn steels with a fixed amount of C + N (0.6 wt pct) was investigated by means of neutron diffraction and transmission electron microscopy (TEM). The SFE were evaluated by the Rietveld whole-profile fitting combined with the double-Voigt size-strain analysis for neutron diffraction profiles using neutron diffraction. The measured SFE showed distinguishable difference and were well correlated with the change in deformation microstructure. Three-dimensional linear regression analyses yielded the relation reflecting the contribution of both C + N and C/N: SFE (mJ/m2) = –5.97 + 39.94(wt pct C + N) + 3.81(C/N). As C fraction increased, the strain-induced γ→ε martensitic transformation was suppressed, and deformation twinning became the primary mode of plastic deformation.
DOI: 10.3389/fpsyg.2012.00241
2012
Cited 54 times
Evidence for Arousal-Biased Competition in Perceptual Learning
Arousal-biased competition theory predicts that arousal biases competition in favor of perceptually salient stimuli and against non-salient stimuli (Mather and Sutherland, 2011). The current study tested this hypothesis by having observers complete many trials in a visual search task in which the target either always was salient (a 55° tilted line among 80° distractors) or non-salient (a 55° tilted line among 50° distractors). Each participant completed one session in an emotional condition, in which visual search trials were preceded by negative arousing images, and one session in a non-emotional condition, in which the arousing images were replaced with neutral images (with session order counterbalanced). Test trials in which the target line had to be selected from among a set of lines with different tilts revealed that the emotional condition enhanced identification of the salient target line tilt but impaired identification of the non-salient target line tilt. Thus, arousal enhanced perceptual learning of salient stimuli but impaired perceptual learning of non-salient stimuli.
DOI: 10.1016/j.actamat.2013.08.046
2013
Cited 48 times
An intersecting-shear model for strain-induced martensitic transformation
Strain-induced martensitic transformation in an austenitic 18Cr–10Mn–0.4N steel was investigated using neutron diffraction and transmission electron microscopy (TEM). Based on experimental evidence from neutron diffraction and TEM indicating that a sequential γ → ε → α′ transformation occurred and the ε intersection played a definite role in the α′ formation, an intersecting-shear model for the strain-induced α′ nucleation at the ε intersection is proposed. Apart from previous models for direct γ → α′ transformation, two-step transformation composed of γ → ε followed by ε → α′ is regarded as a main transformation path. In this model, two invariant-plane strains are required to complete the ε → α′ transformation: the first shear is of the {0 0 0 1}〈101¯0〉 type and amounts to one-half the twinning shear of γ; the second shear whose magnitude is one-third the twinning shear of γ is consecutively introduced parallel to the 〈21¯1¯0〉 direction on the {011¯1} plane. An indirect verification of the model was provided by careful analysis of the precise rotational relationship involved in the ε → α′ transformation. It was found that a partial dislocation ([01¯10]) in moving the ε variant interacted with a partial dislocation ([101¯0]) in the stationary ε variant, and this interaction resulted in the formation of a stair-rod dislocation ([21¯1¯0]) which connects two ε variants.
DOI: 10.1016/j.matchar.2013.05.011
2013
Cited 47 times
Corrosion behavior in high heat input welded heat-affected zone of Ni-free high-nitrogen Fe–18Cr–10Mn–N austenitic stainless steel
The pitting corrosion and interphase corrosion behaviors in high heat input welded heat-affected zone (HAZ) of a metastable high-nitrogen Fe–18Cr–10Mn–N austenitic stainless steel were explored through electrochemical tests. The HAZs were simulated using Gleeble simulator with high heat input welding condition of 300 kJ/cm and the peak temperature of the HAZs was changed from 1200 °C to 1350 °C, aiming to examine the effect of δ-ferrite formation on corrosion behavior. The electrochemical test results show that both pitting corrosion resistance and interphase corrosion resistance were seriously deteriorated by δ-ferrite formation in the HAZ and their aspects were different with increasing δ-ferrite fraction. The pitting corrosion resistance was decreased by the formation of Cr-depleted zone along δ-ferrite/austenite (γ) interphase resulting from δ-ferrite formation; however it didn't depend on δ-ferrite fraction. The interphase corrosion resistance depends on the total amount of Cr-depleted zone as well as ferrite area and thus continuously decreased with increasing δ-ferrite fraction. The different effects of δ-ferrite fraction on pitting corrosion and interphase corrosion were carefully discussed in terms of alloying elements partitioning in the HAZ based on thermodynamic consideration.
DOI: 10.1016/j.electacta.2016.01.118
2016
Cited 47 times
Influences of Mn in solid solution on the pitting corrosion behaviour of Fe-23 wt%Cr-based alloys
The effects of Mn in solid solution on localised corrosion behaviour were investigated using Fe–23 wt% Cr-based alloys containing 0.04-8.01 wt% Mn without Mn-related inclusions. It was revealed that the Mn in solid solution decreased the passive film resistance via incorporation into the passive film, which resulted in lowering the pitting potential value. In addition, it was found that the alloying Mn lowered the repassivation potential, because the Mn in solid solution increased the matrix dissolution rate inside the pit cavity.
DOI: 10.1037/a0037047
2014
Cited 46 times
How arousal modulates the visual contrast sensitivity function.
Recent evidence indicates that emotion enhances contrast thresholds in subsequent visual perception (Phelps, Ling, & Carrasco, 2006) and perceptual sensitivity for low-spatial frequency but not high-spatial frequency targets (Bocanegra & Zeelenberg, 2009b). However, these studies just report responses to various frequencies at a fixed contrast level or responses to various contrasts at a fixed frequency. In the current study, we measured the full contrast sensitivity function as a function of emotional arousal in order to investigate potential interactions between spatial frequency and contrast. We used a Bayesian adaptive inference with a trial-to-trial information gain strategy (Lesmes, Lu, Baek, & Albright, 2010) and a fear-conditioned stimulus to manipulate arousal level. The spatial frequency at which people showed peak contrast sensitivity shifted to lower spatial frequencies in the arousing condition compared with the nonarousing condition and people had greater contrast sensitivity function bandwidth in the arousing than in the nonarousing condition.
DOI: 10.1016/j.ijhydene.2017.08.056
2017
Cited 46 times
Microbial oxidation of antimonite and arsenite by bacteria isolated from antimony-contaminated soils
Two Sb(III)-oxidizing bacteria were isolated from Sb(III)-contaminated soil. By analyzing the 16S rRNA gene, two isolated strains were designated Shinella sp. NLS1 and Ensifer sp. NLS4. Both strains could oxidize Sb(III) to produce Sb(V) under nutrient-limited conditions. Kinetic studies indicated the NLS1 Sb(III) oxidation rate (Vmax = 0.28 μM min−1, Km = 279.13 μM) was comparable to that of NLS4 (Vmax = 0.32 μM min−1, Km = 248.43 μM). NLS1 could also perform aerobic As(III) oxidation and simultaneous oxidation of Sb(III) and As(III). NLS4 was able to perform Sb(III) oxidation under anaerobic conditions with nitrate as an electron acceptor. NLS1 possesses the aioA gene, which might function as both arsenite and antimonite oxidase, whereas strain NLS4 does not. This implies that Sb(III) oxidation in strains NLS1 and NLS4 occurred through two different pathways. This study demonstrates the potential of both isolates for bioremediation of Sb-contaminated sites.
DOI: 10.1007/s10753-014-9899-9
2014
Cited 45 times
Orientin Inhibits HMGB1-Induced Inflammatory Responses in HUVECs and in Murine Polymicrobial Sepsis
DOI: 10.1109/icccn.2016.7568569
2016
Cited 44 times
SDNsec: Forwarding Accountability for the SDN Data Plane
SDN promises to make networks more flexible, programmable, and easier to manage. Inherent security problems in SDN today, however, pose a threat to the promised benefits. First, the network operator lacks tools to proactively ensure that policies will be followed or to reactively inspect the behavior of the network. Second, the distributed nature of state updates at the data plane leads to inconsistent network behavior during reconfigurations. Third, the large flow space makes the data plane susceptible to state exhaustion attacks. This paper presents SDNsec, an SDN security extension that provides forwarding accountability for the SDN data plane. Forwarding rules are encoded in the packet, ensuring consistent network behavior during reconfigurations and limiting state exhaustion attacks due to table lookups. Symmetric-key cryptography is used to protect the integrity of the forwarding rules and enforce them at each switch. A complementary path validation mechanism allows the controller to reactively examine the actual path taken by the packets. Furthermore, we present mechanisms for secure link-failure recovery.
DOI: 10.1016/j.matchar.2015.08.001
2015
Cited 43 times
Evolution of carbides in cold-work tool steels
This study aimed to present the complete history of carbide evolution in a cold-work tool steel along its full processing route for fabrication and application. A sequence of processes from cast to final hardening heat treatment was conducted on an 8% Cr-steel to reproduce a typical commercial processing route in a small scale. The carbides found at each process step were then identified by electron diffraction with energy dispersive spectroscopy in a scanning or transmission electron microscope. After solidification, MC, M7C3 and M2C carbides were identified and the last one dissolved during hot compression at 1180 °C. In a subsequent annealing at 870 °C followed by slow cooling, M6C and M23C6 were added, while they were dissolved in the following austenitization at 1030 °C. After the final tempering at 520 °C, fine M23C6 precipitated again, thus the final microstructure was the tempered martensite with MC, M7C3 and M23C6 carbide. The transient M2C and M6C originated from the segregation of Mo and finally disappeared due to attenuated segregation and the consequent thermodynamic instability.
DOI: 10.1007/s10295-016-1762-6
2016
Cited 43 times
Effect of the cathode potential and sulfate ions on nitrate reduction in a microbial electrochemical denitrification system
Recently, bioelectrochemical systems have been demonstrated as advantageous for denitrification. Here, we investigated the nitrate reduction rate and bacterial community on cathodes at different cathode potentials [-300, -500, -700, and -900 mV vs. standard hydrogen electrode (SHE)] in a two-chamber microbial electrochemical denitrification system and effects of sulfate, a common nitrate co-contaminant, on denitrification efficiency. The results indicated that the highest nitrate reduction rates (3.5 mg L(-1) days(-1)) were obtained at a cathode potential of -700 mV, regardless of sulfate presence, while a lower rate was observed at a more negative cathode potential (-900 mV). Notably, although sulfate ions generally inhibited nitrate reduction, this effect was absent at a cathode potential of -700 mV. Polymerase chain reaction-denaturing gradient gel electrophoresis revealed that bacterial communities on the graphite-felt cathode were significantly affected by the cathode potential change and sulfate presence. Shinella-like and Alicycliphilus-like bacterial species were exclusively observed on cathodes in reactors without sulfate. Ochrobactrum-like and Sinorhizobium-like bacterial species, which persisted at different cathode potentials irrespective of sulfate presence, were shown to contribute to bioelectrochemical denitrification. This study suggested that a cathode potential of around -700 mV versus SHE would ensure optimal nitrate reduction rate and counteract inhibitory effects of sulfate. Additionally, sulfate presence considerably affects denitrification efficiency and microbial community of microbial electrochemical denitrification systems.
DOI: 10.1007/s11661-017-4265-9
2017
Cited 43 times
Microstructure Evolution and Age-Hardening Behavior of Microalloyed Austenitic Fe-30Mn-9Al-0.9C Light-Weight Steels
DOI: 10.1016/j.biortech.2016.04.033
2016
Cited 41 times
Microbial selenite reduction with organic carbon and electrode as sole electron donor by a bacterium isolated from domestic wastewater
Selenium is said to be multifaceted element because it is essential at a low concentration but very toxic at an elevated level. For the purpose of screening a potential microorganism for selenite bioremediation, we isolated a bacterium, named strain THL1, which could perform both heterotrophic selenite reduction, using organic carbons such as acetate, lactate, propionate, and butyrate as electron donors under microaerobic condition, and electrotrophic selenite reduction, using an electrode polarized at −0.3 V (vs. standard hydrogen electrode) as the sole electron donor under anaerobic condition. This bacterium determined to be a new strain of the genus Cronobacter, could remove selenite with an efficiency of up to 100%. This study is the first demonstration on a pure culture could take up electrons from an electrode to perform selenite reduction. The selenium nanoparticles produced by microbial selenite reduction might be considered for recovery and use in the nanotechnology industry.
DOI: 10.1016/j.scriptamat.2016.04.040
2016
Cited 40 times
β-Mn formation and aging effect on the fracture behavior of high-Mn low-density steels
The β-Mn formation behavior of high-Mn low-density steels was investigated in terms of the morphological characteristics and alloying element distribution after aging treatments. A dramatic difference in the formation kinetics and morphology of β-Mn was observed depending on the addition of Al, which may increase the driving force for β-Mn formation. In addition, the effects of the aging process on the fracture behavior were examined in uniaxial tensile tests combined with microstructural observations. A severe loss of ductility resulted from the β-Mn formation and ordering of ferrite into the D03 phase, which was transformed before the β-Mn formation process.
DOI: 10.1111/psyp.13688
2020
Cited 35 times
Cortical thickness and resting‐state cardiac function across the lifespan: A cross‐sectional pooled mega‐analysis
Understanding the association between autonomic nervous system [ANS] function and brain morphology across the lifespan provides important insights into neurovisceral mechanisms underlying health and disease. Resting-state ANS activity, indexed by measures of heart rate [HR] and its variability [HRV] has been associated with brain morphology, particularly cortical thickness [CT]. While findings have been mixed regarding the anatomical distribution and direction of the associations, these inconsistencies may be due to sex and age differences in HR/HRV and CT. Previous studies have been limited by small sample sizes, which impede the assessment of sex differences and aging effects on the association between ANS function and CT. To overcome these limitations, 20 groups worldwide contributed data collected under similar protocols of CT assessment and HR/HRV recording to be pooled in a mega-analysis (N = 1,218 (50.5% female), mean age 36.7 years (range: 12-87)). Findings suggest a decline in HRV as well as CT with increasing age. CT, particularly in the orbitofrontal cortex, explained additional variance in HRV, beyond the effects of aging. This pattern of results may suggest that the decline in HRV with increasing age is related to a decline in orbitofrontal CT. These effects were independent of sex and specific to HRV; with no significant association between CT and HR. Greater CT across the adult lifespan may be vital for the maintenance of healthy cardiac regulation via the ANS-or greater cardiac vagal activity as indirectly reflected in HRV may slow brain atrophy. Findings reveal an important association between CT and cardiac parasympathetic activity with implications for healthy aging and longevity that should be studied further in longitudinal research.
DOI: 10.3389/fnagi.2020.00002
2020
Cited 33 times
The Decline in Intrinsic Connectivity Between the Salience Network and Locus Coeruleus in Older Adults: Implications for Distractibility
We examined functional connectivity between the locus coeruleus (LC) and the salience network in healthy young and older adults to investigate why people become more prone to distraction with age. Recent findings suggest that the LC plays an important role in focusing processing on salient or goal-relevant information from multiple incoming sensory inputs (Mather et al., 2016). We hypothesized that the connection between LC and the salience network declines in older adults, and therefore the salience network fails to appropriately filter out irrelevant sensory signals. To examine this possibility, we used resting-state-like fMRI data, in which all task-related activities were regressed out (Fair et al., 2007; Elliott et al., 2019) and performed a functional connectivity analysis based on the time-course of LC activity. Older adults showed reduced functional connectivity between the LC and salience network compared with younger adults. Additionally, the salience network was relatively more coupled with the frontoparietal network than the default-mode network in older adults compared with younger adults, even though all task-related activities were regressed out. Together, these findings suggest that reduced interactions between LC and the salience network impairs the ability to prioritize the importance of incoming events, and in turn, the salience network fails to initiate network switching (e.g., Menon and Uddin, 2010; Uddin, 2015) that would promote further attentional processing. A chronic lack of functional connection between LC and salience network may limit older adults' attentional and executive control resources.
DOI: 10.1109/access.2020.3029521
2020
Cited 33 times
Single-Trace Attacks on Message Encoding in Lattice-Based KEMs
In this article, we propose single-trace side-channel attacks against lattice-based key encapsulation mechanisms (KEMs) that are the third-round candidates of the national institute of standards and technology (NIST) standardization project. Specifically, we analyze the message encoding operation in the encapsulation phase of lattice-based KEMs to obtain an ephemeral session key. We conclude that a singletrace leakage implies a whole key recovery: the experimental results realized on a ChipWhisperer UFO STM32F3 target board achieve a success rate of 100% for CRYSTALS-KYBER and SABER regardless of an optimization level and those greater than 79% for FrodoKEM. We further demonstrate that the proposed attack methodologies are not restricted to the above algorithms but are widely applicable to other NIST post-quantum cryptography (PQC) candidates, including NTRU Prime and NTRU.
DOI: 10.3389/fgene.2020.00317
2020
Cited 32 times
The Evolution of an Invasive Plant, Sorghum halepense L. (‘Johnsongrass’)
From noble beginnings as a prospective forage, polyploid Sorghum halepense ( 'Johnsongrass') is both an invasive species and one of the world's worst agricultural weeds. Formed by S. bicolor x S. propinquum hybridization, we show S. halepense to have S. bicolor-enriched allele composition and striking mutations in 5,957 genes that differentiate it from representatives of its progenitor species and an outgroup. The spread of S. halepense may have been facilitated by introgression from closely-related cultivated sorghum near genetic loci affecting rhizome development, seed size, and levels of lutein, a photochemical protectant and abscisic acid precursor. Rhizomes, subterranean stems that store carbohydrates and spawn clonal propagules, have growth correlated with reproductive rather than other vegetative tissues, and increase survival of both temperate cold seasons and tropical dry seasons. Rhizomes of S. halepense are more extensive than those of its rhizomatous progenitor S. propinquum, with gene expression including many alleles from its non-rhizomatous S. bicolor progenitor. The first surviving polyploid in its lineage in ~96 million years, its post-Columbian spread across six continents carried rich genetic diversity that in the USA has facilitated transition from agricultural to non-agricultural niches, is projected to spread another 200-600 km northward in the coming century, and may offer novel alleles and traits of value to improvement of sorghum.
DOI: 10.1016/j.matdes.2020.108882
2020
Cited 32 times
Mechanisms for improving tensile properties at elevated temperature in fire-resistant steel with Mo and Nb
Fire resistance of structural steels used in buildings is typically evaluated based on the ratio of the yield strength at 600 °C to that at room temperature. Fire-resistant steel shows a yield strength ratio of more than 2:3 between 600 °C and room temperature and achieves an excellent high-temperature strength. Alloying elements such as Mo and Nb are used to improve the strength at elevated temperatures. In this study, the effects of the addition of Mo and Nb on the fire resistance of steel were carefully investigated using SEM, TEM, in-situ TEM, EPMA, 3D-APT, positron annihilation lifetime spectroscopy, and first principles calculations. The fire resistance in Mo and Nb added steel (Mo + Nb) was shown to be drastically improved compared to plain carbon steel (CMn). The improvement in the high-temperature strength in Mo + Nb was attributed to the precipitation of fine Nb-rich MX particles and a solid solution of Mo and Nb hindering the dislocation movement, and thereby minimizing the dislocation annihilation at elevated temperature. The solid solution of Mo and Nb lowers the vacancy formation energy and allows a vacancy to form more easily, leading to a large lattice distortion which results in a slower dislocation mobility in Mo + Nb.
DOI: 10.1016/j.scitotenv.2021.145904
2021
Cited 27 times
Microbial fuel cells: Devices for real wastewater treatment, rather than electricity production
For last two decades, various microbial fuel cells have been studied to treat real wastewater and simultaneously produce electricity. The performance of 106 MFCs using real wastewater were summarized and grouped according to reactor design (size, shape, and whether single chamber), installation type, operating mode, and wastewater type. Most studies operated MFCs with mini size (<1 L) (57%), box shape (50%), single-chamber (60%), chamber-type (94%), operated under continuous flow mode (67%) with non-domestic wastewater (66%). Their maximum power production and net energy recovery were as low as ~165 W/m3 and ~1.1 kWh/kgCOD, respectively. However, most MFC studies (75/106) using real wastewater achieved higher than 60% of COD removal efficiencies. In addition, recent MFC studies reported successful treatment of nutrients (nitrogen and phosphorus) and antibiotics as well as organics. The review on MFCs using real wastewater suggests that MFC is more proper to apply for wastewater treatment rather than energy production.
DOI: 10.1007/s12257-021-0050-0
2021
Cited 23 times
Suppressive Activities of Fisetin on Particulate Matter-induced Oxidative Stress