Tatsuo Miyazawa

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Infrared Spectra of Polypeptides in Various Conformations: Amide I and II Bands1T. Miyazawa and E. R. BloutCite this: J. Am. Chem. Soc. 1961, 83, 3, 712–719Publication Date (Print):February 1, 1961Publication History Published online1 May 2002Published inissue 1 February 1961https://doi.org/10.1021/ja01464a042RIGHTS & PERMISSIONSArticle Views2382Altmetric-Citations938LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (984 KB) Get e-Alerts Get e-Alerts

The in-plane normal vibrations of N-methylacetamide and its deuterated compound were calculated as a six-body problem. The force constants were transferred from diformylhydrazine and other molecules with similar structures. The normal modes as well as the distributions of the potential energy among symmetry coordinates were also calculated. The result of these calculations allows quantitative discussions concerning the nature of the amide I, II, II′, III, III′, and IV vibrations and other normal vibrations of N-methylacetamide.

A perturbation treatment has been made of localized group vibrations of helical polymer chains. The amide I and II frequencies were derived in terms of adjacent group interactions as well as interchain and intrachain hydrogen bonding interactions. Frequency shifts caused by these interactions depend upon the configuration of polypeptide chains and also upon the chain packing in the crystalline region. Each characteristic vibration of the amide group gives rise to parallel and perpendicular bands. The parallel bands of the α helix of poly-γ-benzyl-L-glutamate were observed at 1650 cm—1 (amide I) and 1516 cm—1 (amide II) whereas the perpendicular bands were observed at 1652 cm—1 (amide I) and 1546 cm—1 (amide II). Both the parallel-chain and antiparallel-chain pleated sheets exhibit the perpendicular amide I band at ca 1630 cm—1. A characteristic band of β configurations at ca 1690 cm—1 was assigned to the parallel amide I band of the antiparallel-chain pleated sheet.

Infrared spectra of various monosubstituted amides and the corresponding deuterated compounds have been measured in the gaseous, liquid, and crystalline states and in solutions. From the experimental results, the bands characteristic of the amide structure have been determined. Furthermore, from the comparison with the spectra of related substances and by the application of the product rule, the assignments of these characteristic bands have been made. The observed change of frequencies of these characteristic bands with change of state confirms this assignment.

A general description has been given of an application of the Wilson's GF-matrix method to the treatment of optically active lattice vibrations. As examples, formulas are derived for the calculation of the frequencies of the lattice vibrations of a one-dimensional, the diamond, and CaF2 lattices.

Normal vibrations of an infinite polymethylene chain in the extended conformation have been treated. The G and F matrices of infinite order may be reduced to the G(δ) and F(δ) matrices of finite order corresponding to the phase difference (δ) between two adjacent methylene groups. The observed vibrational frequencies of long-chain n-paraffins and of polyethylene are compared with the frequencies of polymethylene chain calculated for various phase differences and their assignments have been discussed. A modification of the Urey-Bradley force field has been made in accordance with the present vibrational assignments.

The polarized infrared spectra of highly oriented crystalline films of polyethylene glycol were measured in the region 3500–400 cm—1. Five parallel bands and eleven perpendicular bands due to the fundamental vibrations were observed in the region 1500–600 cm—1. From the analysis of these bands, the polyethylene glycol chain was found to belong to the dihedral group and have twofold axes intersecting the helix axis at right angles. The structural models of polyethylene glycol were discussed by the use of the equations for the helical parameters (the second paper of this series). The most likely model (TGT) contains seven repeating units and two helical turns per fiber period of 19.25 Å. The internal rotation angles for this model are calculated to be 60° for the C–C bond and 191.5° for the C–O bond. The A1, A2, and E(θ) normal vibrations of polyethylene glycol were calculated by the general method for treating helical polymers (the first paper of this series). The normal vibrations of p-dioxane were also calculated. The modified Urey—Bradley force field was used for the calculations and the potential constants were transferred from polyethylene, dimethyl ether, and propyl alcohol. The frequencies calculated for the TGT model agreed well with the observed frequencies. The potential energy distributions were also calculated and the nature of the infrared bands was elucidated. The far-infrared spectra of crystalline films were also measured in the region 600–50 cm—1 and two parallel bands and two perpendicular bands were observed. The skeletal normal vibrations of the TGT model were also calculated, taking into account the torsional potential field. The torsional constants correspond to a potential barrier of 3 kcal/mole. The calculated frequencies agreed well with the observed, providing substantial support for the TGT model. The infrared bands in the region of 3000 cm—1 were assigned to the C–H stretching modes and the infrared active combination vibrations.

Abstract Helical conformations of infinite polymer chains may be described by the helical parameters including ρ i (the distance of the i th atom from the helix axis), d ij (the translation along the axis), and θ ij (the angle of rotation about the axis on passing from the i th atom to the j th). For the polymer main chain (M) ∞ , (M 1 M 2 ) ∞ , (M 1 M 2 M 3 ) ∞ , (M 1 M 2 M 3 M 4 ) ∞ , (M 1 M 2 M 3 M 4 M 5 ) ∞ , (M 1 M 2 M 3 M 4 M 5 M 6 ) ∞ concise mathematical equations for the helical parameters are given in terms of the internal coordinates, such as the bond lengths, the bond angles, and the internal rotation angles. These equations are useful in calculating the internal coordinates and in selecting likely structure models from the helical parameters experimentally determined. The internal coordinates and helical parameters of polyethylene, polytetrafluoroethylene, sulfur, selenium, tellurium, isotactic polypropylene, poly‐4‐methyl‐1‐pentene, poly‐ m ‐methylstyrene, poly‐o‐methylstyrene, polyoxymethylene, polyisobutylene, polypeptides (α helix, parallel‐chain, or antiparallel‐chain extended form), polyglycine II, polyethylene glycol, and syndiotactic polypropylene were calculated and were used for discussing the structure of these helical polymers.

The infrared spectra of the four isotopic species of formic acid were measured in the vapor phase as well as in the solid nitrogen matrix in the region 400–800 cm—1. Absorption bands in the vapor phase were analyzed by considerations of band contours and comparisons with the frequencies distinctly observed in the matrix, and the previous assignment was revised. The torsional vibrations of the terminal OH groups of short chain polymers of HCOOH were observed in the matrix at 685 and 694 cm—1. The OH torsional frequencies of the trans isomer were located in the vapor phase at 582 (HCOOH), 576 (DCOOH), 450 (HCOOD), and 448 cm—1 (DCOOD). The energy difference between the two isomers was determined to be 2.0±0.3 kcal/mole. The potential hindering internal rotation was calculated to be 2V (kcal/mole)=2·1(1−cosθ)+9·9(1−cos2θ)−0·1(1−cos3θ) from the energy difference and the fundamental torsional frequencies. The entropy of mixing of the two isomers was found to be 0.3±0.1 cal deg—1 mole—1 at 25°C. A normal coordinate treatment was made of the cis and trans isomers of monomer and of the dimer and polymer. The double bond characters calculated from the torsional potential constant agree with those calculated from bond lengths.

The resonance Raman spectra of β-carotene in isopentane solution have been obtained at low temperature, using eight output lines of the argon-ion laser and a line of the heliumcadmium laser. The excitation profiles of three fundamentals, two overtones, and two combination tones are presented and analyzed in terms of the Albrecht theory. The overlap integrals between the vibrational wavefunctions of the ground and first excited electronic states are shown to be the most important factor for the resonance Raman intensities of the β-carotene molecule. The observed excitation profiles and absorption spectrum at low temperature have been successfully simulated by assuming small displacements of the equilibrium nuclear positions in going from the ground electronic state to the first excited. Elongation of CC bonds and shrinkage of CC bonds in the excited electronic state have also been estimated.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConformational rigidity of specific pyrimidine residues in tRNA arises from posttranscriptional modifications that enhance steric interaction between the base and the 2'-hydroxyl groupGota Kawai, Yuriko Yamamoto, Takashi Kamimura, Tsukio Masegi, Mitsuo Sekine, Tsujiaki Hata, Takamasa Iimori, Tatsuo Watanabe, Tatsuo Miyazawa, and Shigeyuki YokoyamaCite this: Biochemistry 1992, 31, 4, 1040–1046Publication Date (Print):February 1, 1992Publication History Published online1 May 2002Published inissue 1 February 1992https://doi.org/10.1021/bi00119a012RIGHTS & PERMISSIONSArticle Views505Altmetric-Citations173LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (788 KB) Get e-Alertsclose Get e-Alerts

Abstract The infrared and Raman spectra of several dialkyl disulfides were measured and their conformations were discussed in relation with the characteristic S–S and C–S stretching vibrations. The infrared spectra in the solid state and the temperature dependence of Raman spectra were measured for ethyl methyl disulfide and diethyl disulfide. For ethyl methyl disulfide, the gauche-gauche isomer was more stable than the trans-gauche isomer by about 0.9 kcal/mol while for diethyl disulfide the gauche-gauche-gauche isomer was more stable than the trans-gauche-gauche isomer by about 0.6 kcal/mol in the liquid state. Only the gauche-gauche form for ethyl methyl disulfide and only the gauche-gauche-gauche form for diethyl disulfide were observed in the solid state.

The backbone 1H, 13C, and 15N resonances of the c-Ha-Ras protein [a truncated version consisting of residues 1-171, Ras(1-171)] bound with GMPPNP (a slowly hydrolyzable analogue of GTP) were assigned and compared with those of the GDP-bound Ras(1-171). The backbone amide resonances of amino acid residues 10-13, 21, 31-39, 57-64, and 71 of Ras(1-171).GMPPNP, but not those of Ras(1-171).GDP, were extremely broadened, whereas other residues of Ras(1-171).GMPPNP exhibited amide resonances nearly as sharp as those of Ras(1-171). GDP. The residues exhibiting the extreme broadening, except for residues 21 and 71, are localized in three functional loop regions [loops L1, L2 (switch I), and L4 (switch II)], which are involved in hydrolysis of GTP and interactions with other proteins. From the temperature and magnetic field strength dependencies of the backbone amide resonance intensities, the extreme broadening was ascribed to the exchange at an intermediate rate on the NMR time scale. It was shown that the Ras(1-171) protein bound with GTP or GTPgammaS (another slowly hydrolyzable analogue of GTP) exhibits the same type of broadening. Therefore, it is a characteristic feature of the GTP-bound form of Ras that the L1, L2, and L4 loop regions, but not other regions, are in a rather slow interconversion between two or more stable conformers. This phenomenon, termed a "regional polysterism", of these loop regions may be related with their multifunctionality: the GTP-dependent interactions with several downstream target groups such as the Raf and RalGDS families and also with the GTPase activating protein (GAP) family. In fact, the binding of Ras(1-171).GMPPNP with the Ras-binding domain (residues 51-131) of c-Raf-1 was shown to eliminate the regional polysterism nearly completely. It was indicated, therefore, that each target/regulator selects its appropriate conformer among those presented by the "polysteric" binding interface of Ras. As the downstream target groups exhibit no apparent sequence homology to each other, it is possible that one target group prefers a conformer different from that preferred by another group. The involvement of loop L1 in the regional polysterism might suggest that the negative regulators, GAPs, bind to the polysteric binding interface (loops L2 and L4) of Ras and cooperatively select a conformer suitable for transition of the GTPase catalytic center, involving loops L1 and L4, into the highly active state.

The conformational change upon binding with phospholipid membrane has been studied of mastoparan from wasp venom, a tetradecapeptide causing the degranulation of mast cells. The 270-MHz 1H-NMR spectra and CD spectra indicate that the mastoparan molecule takes the alpha-helical conformation in methanol solution, but a much less ordered form in aqueous solution. On binding with phospholipid membrane, the alpha-helical conformation is formed even in aqueous medium. Such a conformational change is primarily due to the interaction between the aliphatic side chains of mastoparan and the hydrophobic interior of phospholipid membrane, in contrast to the case of melittin from bee venom.

A minor species of isoleucine tRNA (tRNA(minor Ile)) specific to the codon AUA has been isolated from Escherichia coli B and a modified nucleoside N+ has been found in the first position of the anticodon (Harada, F., and Nishimura, S. (1974) Biochemistry 13, 300-307). In the present study, tRNA(minor Ile)) was purified from E. coli A19, and nucleoside N+ was prepared, by high-performance liquid chromatography, in an amount (0.6) A260 units) sufficient for the determination of chemical structures. By 400 MHz 1H NMR analysis, nucleoside N+ was found to have a pyrimidine moiety and a lysine moiety, the epsilon amino group of which was involved in the linkage between these two moieties. From the NMR analysis together with mass spectrometry, the structure of nucleoside N+ was determined as 4-amino-2-(N6-lysino)-1-(beta-D-ribofuranosyl)pyrimidinium (lysidine), which was confirmed by chemical synthesis. Lysidine is a novel type of modified cytidine with a lysine moiety and has one positive charge. Probably because of such a unique structure, lysidine in the first position of anticodon recognizes adenosine but not guanosine in the third position of codon.

Novel applications of nuclear magnetic resonance (NMR) spectroscopy in biochemistry are reviewed. The biological functions of peptides are correlated with the conformations of membrane-bound molecules rather than the conformations in aqueous solutions. The membrane-bound conformations may be elucidated by the analysis of transferred nuclear Overhauser effects. The conformations of nucleotide inhibitors as bound to ribonucleases may be analysed by nuclear Overhauser effect. Thus, ribonuclease T1 is found to have binding sites for guanine base and 3'-phosphate but not for 5'-phosphate group. From the 13C-NMR spectra of subtilisin inhibitors as labeled with [1-13C] Met and [15N]-Val, the inhibitor is found to form a Michaelis complex with subtilisin. From the proton NMR analyses of immunoglobin (IgG), the hinge region (indispensable for the activation of complement system) is found to be the most mobile. The uridine residue in the first position of anticodon of transfer ribonucleic acids (tRNA) are always modified after transcription. The conformational characteristics of the modified uridines have been elucidated by proton NMR analyses. The modifications of uridine in the first position of anticodon are now found to contribute to correct and efficient translations of codons, through the regulation of rigidity/flexibility of the anticodon moiety of tRNA.

The normal coordinate treatment of the (—A—)n chain was made in terms of internal symmetry coordinates and optically active frequencies of (—CH2—)n were calculated for various chain conformations. The calculated frequencies of polyethylene and cyclopentane agreed with the observed values. The low infrared frequency was found to be structure sensitive. The infrared band of polytetrafluoroethylene at approx 100 cm—1 may be primarily due to this mode. The low infrared frequencies of polyoxymethylene were compared with the corresponding frequencies of (—A—)n calculated for various conformations and were found to be in accord with Huggins' model but not with the planar zigzag structure. The normal coordinate treatment of (—A—B—)n was made taking into account the torsional potential as well as the stretching and bending potentials, and vibrational assignments of polyoxymethylene were made. For poly-(ethylene glycol) a structure model was proposed. This model is made up of only the gauche configuration throughout the helical chain and contains seven chemical units and five turns of the helix per fiber period. The polarized infrared spectra of this polymer were measured in the region 800–400 cm—1 and the observed skeletal frequencies were compared with the corresponding frequencies of (—A—)n calculated for various conformations. The infrared spectra were found to be in accord with the model proposed here. The infrared spectra in the rocksalt region were also reasonably assigned. Finally a general method of treating any infinite helical chain belonging to dihedral group is presented in terms of real internal symmetry coordinates. The G or F matrix of an infinite order is factored into the set of matrices G(δ) or F(δ) associated with the phase difference δ. The method is explained for the cases of polyoxymethylene and poly-(ethylene glycol).

The infrared spectra of diketopiperazine and its N-deuterated compound were measured in the region 1800-200 cm−1. The in-plane normal vibrations of the cis isomer of N-methylacetamide and its N-deuterated compound were calculated as a six-body problem. These calculations permit the vibrational assignment of diketopiperazine and some quantitative discussion about the nature of the characteristic vibrations of the cis CONH group. The NH bending and CN stretching vibrations were located at 1450 cm−1 and 1350 cm−1. The band of the cis CONH group at 3100 cm−1 was assigned to the combination band of the CO stretching and NH bending vibrations, resolving the difficulty encountered in assigning the similar band of the trans CONH group to the overtone of the amide II vibration. The band of N-methylformamide vapor at 1280 cm−1 was assigned to the CN stretching mode of the cis isomer; however, the trans isomer is considered to be predominant in the vapor.

Abstract Helical conformations of infinite polymer chains may be described by the helical parameters, d and θ (the translation along the helix axis and the angle of rotation about the axis per repeat unit), pi (the distance of the i th atom from the axis), d ij , and d ij (the translation along the axis and the angle of rotation, respectively, on passing from the i th atom to the j th). A general method has been worked out for calculating all those helical parameters from the bond lengths, bond angles, and internal‐rotation angles. The positions of the main chain and side chain atoms with respect to the axis may also be calculated. All the equations are applicable to any helical polymer chain and are readily programmed for electronic computers. A method is also presented for calculating the partial derivatives of helical parameters with respect to molecular parameters.

Abstract A new potent mutagen was isolated from fried beef. The molecular formula was determined as C11H11N5 by exact mass measurement. The chemical structure of this mutagen was determined to be 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (Me-IQx) by the analyses of its UV, mass and 1H-NMR spectra, and chemical synthesis.

Raman and infrared spectra of dialkyl disulfides were measured. Correlations of S–S and C–S stretching frequencies to molecular conformations were found for dialkyl disulfides.The molecular structure of cystine in aqueous solution was studied on the basis of the observed S–S and C–S stretching vibrations.

Infra-red absorption spectra of urea and urea-d4 have been measured. Infra-red dichroic measurement and Raman measurement have been made for urea in the crystalline state. The normal vibrations of the planar C2v model have been calculated as an eight-body problem and the assignment of the observed frequencies has been made.

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe by performing high-resolution, high-throughput spectroscopy with moderate angular resolution. ASTRO-H covers very wide energy range from 0.3 keV to 600 keV. ASTRO-H allows a combination of wide band X-ray spectroscopy (5-80 keV) provided by multilayer coating, focusing hard X-ray mirrors and hard X-ray imaging detectors, and high energy-resolution soft X-ray spectroscopy (0.3-12 keV) provided by thin-foil X-ray optics and a micro-calorimeter array. The mission will also carry an X-ray CCD camera as a focal plane detector for a soft X-ray telescope (0.4-12 keV) and a non-focusing soft gamma-ray detector (40-600 keV) . The micro-calorimeter system is developed by an international collaboration led by ISAS/JAXA and NASA. The simultaneous broad bandpass, coupled with high spectral resolution of ΔE ~7 eV provided by the micro-calorimeter will enable a wide variety of important science themes to be pursued.

Abstract The normal frequencies and vibrational modes have been calculated for two models of an infinite polyene chain using a modified Urey‐Bradley force field. The vibrational modes giving rise to strong resonance Raman lines have been elucidated on the basis of the results of the calculation.

The characteristic band of secondary amides at 3100 cm−1 was explained to be due to the Fermi resonance of the NH stretching vibration with the overtone of the amide II vibration for the trans configuration and with the combination of the CO stretching and NH in-plane bending vibrations for the cis configuration. The NH stretching frequencies of secondary amides should be corrected for the Fermi resonance before they are correlated with the strengths of hydrogen bonds.

Abstract The infrared absorption of poly(ethylene glycol) was measured in the molten state. Characteristic bands of the molten state were identified. Normal vibrations and frequency distributions were treated for various conformation models with CH 2 CH 2 O repeat units. The infrared absorption peaks of the molten state closely correspond to the frequency distribution peaks of the TGT conformation with gauche OCH 2 CH 2 O groups, although infrared bands due to trans OCH 2 CH 2 O groups are also observed. Vibrational assignments of the infrared bands and Raman lines were made on the basis of potential energy distributions.

The infrared spectra of cyclohexane have been studied in the region of 4000-150 cm−1 in the liquid and vapor states. The infrared band due to the Eu skeletal deformation vibration was found at 248 cm−1. The calculation of Coriolis coupling constants has also been carried out along with the normal coordinate treatment using a modified Urey-Bradley force field. The assignment of the infrared and Raman bands was made with reference to the results of this calculation.

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The infra-red spectra of simple metal oxalates have been measured and the assignment of bands haa been based on the normal vibration calculation for the free oxalate ion. The infra-red spectra of oxalato complexes of Fe(III), Co(III), Cr(III), Al(III), Pd(II), and Cu(II) have been measured in the NaCl and CsBr regions. Assignment of bands has been made by the comparison of the spectra with those of alkali metal oxalates and dimethyl oxalate.

We investigated the dependency of minority carrier lifetimes on the nitrogen concentration, temperature, and the injected carrier concentration for highly nitrogen-doped 4H-SiC epilayers. The minority carrier lifetimes greatly shortened when the nitrogen concentration exceeded 1018 cm−3 through enhancing direct band-to-band and Auger recombination and showed a slight variation in the temperature range from room temperature (RT) to 250 °C. The epilayer with a nitrogen concentration of 9.3 × 1018 cm−3 exhibited a very short minority carrier lifetime of 38 ns at RT and 43 ns at 250 °C. The short minority carrier lifetimes of the highly nitrogen-doped epilayer were confirmed to maintain the values even after the subsequent annealing of 1700 °C. 4H-SiC PiN diodes were fabricated by depositing a highly nitrogen-doped epilayer as a “recombination enhancing layer” between an n− drift layer free from basal plane dislocations and the substrate. The PiN diodes showed no formation of stacking faults and no increase in forward voltage during current conduction of 600 A/cm2 (DC), demonstrating that a highly nitrogen-doped buffer layer with a short minority carrier lifetime successfully suppresses the “bipolar degradation” phenomenon.

We present results from the first demonstration of a fully integrated SDN-controlled bandwidth-flexible and programmable SDM optical network utilizing sliceable self-homodyne spatial superchannels to support dynamic bandwidth and QoT provisioning, infrastructure slicing and isolation. Results show that SDN is a suitable control plane solution for the high-capacity flexible SDM network. It is able to provision end-to-end bandwidth and QoT requests according to user requirements, considering the unique characteristics of the underlying SDM infrastructure.

Raman spectra of chloroacetone were measured in the liquid and solid states and in solutions. Infrared absorption spectra of this substance were measured in the gaseous, liquid, and solid states and in solutions. The temperature dependence of the intensity of the Raman lines and of the absorption bands were measured in the liquid state. From the experimental results together with the dipole data it was concluded that chloroacetone exists in two molecular forms in the liquid and gaseous states and in one form in the solid state. The less stable form in the liquid state becomes much more abundant than the other form in the gaseous state. Some considerations on the nature of hindering potential of internal rotation have been made.

We aimed to clarify the behavior of change in the grain structure and hardness of hot-rolled pure W and its alloys plates developed for various properties by holding at high temperature for long and short durations in the absence of irradiation. The isothermal annealing was performed at 1100 °C for 10–3115 h. The isochronous annealing was performed for 1 h in a temperature range of 1100 to 2300 °C. After heat treatment, the grain structure was observed using electron backscatter diffraction (EBSD) and the Vickers hardness was measured in the observed plane. Pure W did not recrystallize by the heat treatment for a short duration of 1 h at 1100 °C, while the recrystallization of pure W progressed during the heat treatment for long duration of 3115 h at 1100 °C. The temperature and duration at which the recrystallization occurs increase because of the dispersion of K bubbles and solid solution of Re. Considering the actual operation period of fusion reactors, a temperature of 1100 °C can result in recrystallization. It is necessary to decrease the maximum operating temperature or to use materials having a high recrystallization temperature by alloying.

The Raman spectra of chloroacetyl chloride, bromoacetyl chloride, and bromoacetyl bromide have been measured in the solid and liquid states. The infrared absorption spectra of these substances have also been measured in the liquid and the gaseous states. From the experimental results it has been concluded that there are two rotational isomers in the liquid and gaseous states and only one of them persists in the solid state. The temperature dependence of the intensity of the infrared absorption in the gaseous state has also been studied, and the energy difference between these two isomers has been found as 1.0±0.1 kcal/mol for bromoacetyl chloride and 1.9±0.3 kcal/mol for bromoacetyl bromide. The calculation of the normal vibrations and of the product rule has been made for various configurations of rotational isomers, and it has been shown that the more stable form is the trans form (or nearly this one) with regard to the two halogen atoms. The less stable form is considered to have an azimuthal angle between the two carbon-halogen bonds of about 150°.

The crystal structure of a class I aminoacyl-transfer RNA synthetase, glutamyl-tRNA synthetase (GluRS) from Thermus thermophilus , was solved and refined at 2.5 Å resolution. The amino-terminal half of GluRS shows a geometrical similarity with that of Escherichia coli glutaminyl-tRNA synthetase (GlnRS) of the same subclass in class I, comprising the class I-specific Rossmann fold domain and the intervening subclass-specific α/β domain. These domains were found to have two GluRS-specific, secondary-structure insertions, which then participated in the specific recognition of the D and acceptor stems of tRNA Glu as indicated by mutagenesis analyses based on the docking properties of GluRS and tRNA. In striking contrast to the β-barrel structure of the GlnRS carboxyl-terminal half, the GluRS carboxyl-terminal half displayed an all-α-helix architecture, an α-helix cage, and mutagenesis analyses indicated that it had a role in the anticodon recognition.

The complex [BuMeIm]2[UCl6] was characterized in the solid state and in a solution of [BuMeIm][Tf2N] room temperature ionic liquid using single-crystal XRD, EXAFS, visible absorption spectroscopy and NMR techniques.The structure of solid [BuMeIm]2[UCl6] contains two crystallographically independent formula units (U(1) and U(2)).The U–Cl distances in UCl62- anions range from 2.576(6) to 2.638(4) Å, the average values being 2.621(6) and 2.601(8) Å for U(1) and U(2), respectively.The BuMeIm+ cations have four different conformations of C4H9 chains.The shortest distances between the centres of the five-member rings of the BuMeIm+ cations and U atoms of [UCl6]2− anions are in the range 5.53–4.90 Å.Single-crystal XRD data reveal the existence of a hydrogen bond between the most acidic H atom of the imidazolium ring (C2) and the chloride anion of the UCl62- octahedron, with the shortest distance Cl⋯H(C2) equal to 2.57 Å.Quantitative EXAFS measurements indicate that the octahedral complex UCl62-(RU–Cl = 2.632(2) Å) is the predominant chemical form of U(IV) in [BuMeIm][Tf2N] solution.Visible absorption spectroscopy and 1H NMR spectroscopy confirm the existence of hydrogen bonding between theUCl62- anion and the acidic proton of the BuMeIm+ cation in RTIL solution, similar to that in the solid state.

The authors investigated the application of the carbon-implantation/annealing method for the annealing of the main lifetime limiting defect Z1∕2 in thick 4H–SiC epilayers. Examination of different implantation doses and annealing temperatures showed that finding the optimum conditions is crucial for obtaining thick layers with carrier trap concentration below 1011cm−3 in the whole 100μm epilayer. The carrier lifetime increased from less than 200ns to over 1μs at room temperature in the samples annealed with the carbon-implanted layer. The thick 4H–SiC epilayers after the application of the carbon-implantation/annealing were confirmed to be applicable for fabrication of high-voltage bipolar devices and resulted in improved conductivity modulation. Possible annealing mechanisms are discussed in detail making a comparison between annealing of as-grown material and irradiated material.

Mastoparan-X, a tetradecapeptide from wasp venom, has been proposed to cause secretion from various kinds of cells by the direct activation of GTP-binding regulatory proteins (G proteins) that couple to phospholipase C. The mechanism of the activation has been shown to be very similar to that of G-protein-coupled receptors in vitro, and the interaction with membranes seems to be very important for the activation of G proteins that are membrane-bound [Higashijima, T., Uzu, S., Nakajima, T., & Ross, E. M. (1988) J. Biol. Chem. 263, 6491-6494]. We report here the precise vesicle-bound conformation of mastoparan-X in the presence of perdeuterated phospholipid vesicles, determined by two-dimensional 1H-NMR analyses of transferred nuclear Overhauser effects, combined with distance geometry and molecular dynamics calculations. Of 14 amino acid residues, the C-terminal 12 residues take an alpha-helical conformation upon binding to the phospholipid bilayer. The overall structure of the alpha-helix is amphiphilic, with three lysine side chains located on one side and with hydrophobic side chains on the other side. This conformation of mastoparan-X was maintained both in the gel and in the liquid-crystalline phases of the membranes. The conformation described herein will provide a useful basis for understanding conformation-activity relationships of mastoparan analogs as activators of G proteins. These studies will help to design novel potent analogs for the regulation of G proteins and to analyze receptor-G-protein interactions.

Abstract The nmr titration curves of chemical shifts versus pH were observed for the protons of various histidine‐containing di‐ and tripeptides. With these results, the macroscopic p K a values and the chemical shifts intrinsic to each ionic species were determined by a computer curve‐fitting based on a simple acid dissociation sequence. The p K a value of the imidazole ring in N ‐acetyl‐ L ‐histidine methylamide was assumed to represent the intrinsic (or unperturbed) p K a of the imidazole rings of histidine having peptide linkages at both the CO and NH sides. The p K a values of the imidazole rings observed for most di‐ and tripeptides were reasonably reproduced by simple calculations using the intrinsic value and the perturbations due to the CO 2 − and NH 3 + groups located at various positions. Some other factors affecting the p K a value of the imidazole ring are also discussed.

The 270-MHz 1H and 68-MHz 13C nuclear magnetic resonance spectra of Met-enkephalin (Tyr-Gly-Gly-Phe-Met) and Met-enkephalinamide are analyzed in a variety of solvents. For the dipolar form of Met-enkephalin in (C2H3)2SO solution, significant concentration dependences are found of C-alpha proton chemical shifts, indicating an aromatic ring-current effect in molecular aggregates. An anomalous temperature dependence is observed of the amide proton chemical shift of the Met-5 residue. Furthermore, the chemical shifts of C-alpha protons of the dipolar form are found to depend appreciably on temperature. From the analyses of the temperature dependences together with concentration dependences of C-alpha proton resonances, the dipolar form of Met-enkephalin is found to be in an equilibrium of folded and extended conformations at low concentration in (C2H3)2SO solution. Solvent-composition dependences of the amide and C-alpha proton resonances and carbonyl and alpha-carbon resonances of the dipolar form in 2H2O/(C2H3)2SO solution are consistent with the conformation equilibrium and the association equilibrium. The folded conformation of the dipolar form in (C2H3)2SO solution is stabilized by the intramolecular attraction between the positively charged N-terminal group and negatively charged C-terminal group. The presence of the folded conformation is confirmed by the measurements of Gd(III)-induced relaxation enhancements of C-alpha protons. Nuclear Overhauser effects on the dipolar form are not consistent with the predominant formation of the beta-turn structure with the intramolecular hydrogen bond (Gly-2) C=O . H-N(Met-5). For the dipolar form of Met-enkephalin in 2H2O solution and for the cationic form of Met-enkephalinamide in (C2H3)2SO solution and in 2H2O solution there is no evidence for the formation of folded conformations.

The structure of the branching site of poly(ADP-ribose) was determined as @a-D-ribofuranosyl-(l"' + Z")-O-a-D-ribofuranosyl-(l" + Z')-adenosine-5',5",5'"tris(phosphate) by gas chromatography, mass spectrometry, and 'H-NMR measurements.Thus the structures of all the ribose-ribose linkages known in poly(ADP-ribose) are uniformly a(l + %)glycosidic bond.This indicates that branching ADP-ribosylation and elongating ADP-ribosylation of poly(ADP-ribose) synthesis are catalyzed by similar a(l + 2)-specific ADP-ribosyl transferases or the same enzyme.Poly(ADP-ribose) glycohydrolase, which specifically hydrolyzes the ribose-ribose bonds of poly(ADP-ribose), also cleaves the ribose-ribose-ribose bonds at the site of branching.Poly(ADP-Rib)' is a nucleic acid-like biopolymer synthesized from /?-NAD+ with chromatin-bound enzyme (1-5).An ADP-ribosylation reaction has been suggested to play a role in regulation of DNA synthesis, DNA repair, cell differentiation, transformation, and chromatin structure (1-5).Poly(ADP-Rib) was first thought to be a linear chain of ADP-ribose residues linked through a(1 + 2)-ribose-ribose glycosidic bonds (6-9), but unexpectedly, recent findings indicate that poly(ADP-Rib) has a branched structure (10,11).In this sense, poly(ADP-Rib) may be similar to polysaccharides with branches.A tentative structure of the branching site of poly(ADP-Rib) has been reported as 2"[l"-ribosyl-2"-(or 3")(l"'"ibosyl)]adenosine-5',5",5"-tris(phosphate), which

Polarized infrared spectra of an oriented crystalline film of isotactic polypropylene have been measured in the region 600–300 cm—1. Two parallel bands and three perpendicular bands due to the skeletal deformation modes have been observed. A general method for treating the normal vibrations (with any given phase difference) of infinite helical chain polymers has been restudied. The method has been applied to the infrared active normal vibrations, A and E(⅔π), of isotactic polypropylene. The modified Urey—Bradley force field has been used and the potential constants have been transferred from aliphatic hydrocarbons. The calculated frequencies and potential energy distributions have been used as aids in assigning the infrared bands of isotactic polypropylene in the region 1500–300 cm—1.

Infrared spectra of CH3O(-CH2CH2O-)pCH3 (p = 1–7) in the crystalline state have been measured in the region 4000-400 cm−1. Assignments of absorption bands have been made with reference to the dispersion curves (wavenumber vs. phase difference) calculated for an infinite chain of poly(ethylene glycol). Normal coordinates have also been treated on some of these molecules in order to check the vibrational assignments. The band progression observed at 520–590 cm−1 has been analyzed on the basis of the coupled oscillator model. Chain conformation of these molecules in the crystalline state is similar to that of the high polymer.

Abstract Normal vibrations of polyethylene glycol and the perdeuterated species were treated. Intrachain force field was expressed in terms of local-symmetry coordinates. Force constants were adjusted by the method of least squares, with reference to observed infrared and Raman frequencies. A set of force constants was obtained, which reproduces the observed frequencies with an r. m. s. deviation of 0.9%. The values of the force constants thus refined were discussed in comparison with corresponding values of related molecules. Vibrational assignments of the observed infrared absorption bands and Raman lines were revised on the basis of potential-energy distributions refined in the present treatment.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLow Frequency Vibrations, Polarizability and Entropy of Carboxylic Acid Dimers1Tatsuo Miyazawa and Kenneth S. PitzerCite this: J. Am. Chem. Soc. 1959, 81, 1, 74–79Publication Date (Print):January 1, 1959Publication History Published online1 May 2002Published inissue 1 January 1959https://doi.org/10.1021/ja01510a016RIGHTS & PERMISSIONSArticle Views235Altmetric-Citations69LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (718 KB) Get e-Alertsclose Get e-Alerts

Infrared spectra of ethylene- through heptaethyleneglycol dimethylethers and Raman spectra of ethylene- through tetraethyleneglycol dimethylethers have been measured in the liquid state. Assignments of the vibrational frequencies have been made and the effect of the chain length on the spectra has been discussed with reference to the nature of vibrational modes. The CH2 rocking and the CO and CC stretching modes are appreciably coupled. In the liquid state the internal rotation angles (trans and gauche) about the CC and the CO bonds of the molecular chain are randomly distributed.

Abstract The infrared spectra of ethylene glycol and ethylene glycol-d2 have been measured in the liquid and crystalline states in the region 4000—300 cm−1. The infrared and Raman spectra suggest that ethylene glycol molecule takes only the gauche conformation as to the C-C bond in both states (the likely models are TGT, TGG and GGG). To establish the vibrationarassignments, the normal coordinate treatments of ethylene glycol and its three deuterated derivatives have been carried out for these models by the use of GF matrix method. The modified Urey-Bradley force field has been used and the force constants have been transferred from similar molecules. The potential energy distributions have also been calculated and the nature of the observed infrared bands and Raman lines in the liquid state has been discussed. The empirical assignments of the methylene rocking modes by the previous investigators have been revised by the present normal coordinate analyses.

A refined treatment has been made for the torsional coordinate around the CC bond of a polymethylene chain. A coordinate (Δt) which is set up from the torsional internal coordinates around the CC bond and equals the change of the internal rotation angle has been introduced. On assuming the internal rotation potential of the type 12Y(Δt)2, an agreement between the observed and the calculated frequencies of the out-of-plane vibrations of a polymethylene chain has been obtained. Force constants have been refined.

We present the first elastic, space division multiplexing, and multi-granular network based on two 7-core MCF links and four programmable optical nodes able to switch traffic utilising the space, frequency and time dimensions with over 6000-fold bandwidth granularity. Results show good end-to-end performance on all channels with power penalties between 0.75 dB and 3.7 dB.

Machine learning has the capability to provide simpler solutions to complex problems by analyzing a huge volume of data in a short time, learning for adapting its functionality to dynamically changing environments, and predicting near future events with reasonably good accuracy. The 5G communication networks are getting complex due to emergence of unprecedentedly huge number of new connected devices and new types of services. Moreover, the requirements of creating virtual network slices suitable to provide optimal services for diverse users and applications are posing challenges to the efficient management of network resources, processing information about a huge volume of traffic, staying robust against all potential security threats, and adaptively adjustment of network functionality for time-varying workload. In this paper, we introduce about the envisioned 5G network slicing and elaborate the necessity of automation of network functions for the design, construction, deployment, operation, control and management of network slices. We then revisit the machine learning techniques that can be applied for the automation of network functions. We also discuss the status of artificial intelligence and machine learning related activities being progressed in standards development organizations and industrial forums.

Abstract Infrared spectra of n-propyl chloride and bromide have been measured in the gaseous, liquid and solid states. The Raman measurement was also made in the liquid state. From the normal vibration calculation and by comparison with the spectra of ethylene chlorhydrin it has been concluded that in the liquid state both the trans and gauche forms are present and of these only the trans form persists in the solid state. The energy difference between the trans and the gauche forms has been determined by the absorption intensity measurement.

This paper reports recent advances in high-quality 4H-SiC epitaxial growth. The modern 4H-SiC epitaxial reactors, techniques to improve growth rates and large-diameter uniformity and reduce defect densities are discussed. A single-wafer vertical-type epitaxial reactor is newly developed and employed to grow 150 mm-diameter 4H-SiC epilayers. Using the reactor, high-speed wafer rotation is confirmed effective, both for enhancing growth rates and improving thickness and doping uniformities. Current levels of reducing particle-induced defects, in-grown stacking faults and basal plane dislocations and controlling carrier lifetimes are also reviewed.

We investigated the relationship between the dislocation velocity and the injected carrier concentration on the expansion of single Shockley-type stacking faults by monitoring the electroluminescence from 4H-SiC PiN diodes with various anode Al concentrations. The injected carrier concentration was calculated using a device simulation that took into account the measured accumulated charge in the drift layer during diode turn-off. The dislocation velocity was strongly dependent on the injected hole concentration, which represents the excess carrier concentration. The activation energy of the dislocation velocity was quite small (below 0.001 eV between 310 and 386 K) over a fixed range of hole concentrations. The average threshold hole concentration required for the expansion of bar-shaped single Shockley-type stacking faults at the interface between the buffer layer and the substrate was determined to be 1.6–2.5 × 1016 cm−3 for diodes with a p-type epitaxial anode with various Al concentrations.

To clarify the irradiation hardening behavior of neutron-irradiated tungsten(W), the formation behavior of rhenium(Re)-enriched cluster and W-Re precipitation with displacement damage in fission reactors environment was investigated by the atom probe tomography (APT) technique, and the results obtained by APT and microstructural observation by transmission electron microscopy (TEM) were compared. Neutron-irradiated pure W and W-10Re alloys were used for the analysis. These samples were irradiated to 0.96 dpa at 538 °C in a fast experimental reactor Joyo, and irradiated to 0.90 dpa at 500 °C in a mixed spectrum reactor HFIR. The chemical compositions of the matrix, Re clusters, and precipitates were determined by the AP analysis. The Joyo-irradiated samples contained lower levels of transmuted Re and Os, while the HFIR-irradiated samples contained higher levels of Re and Os. The Re-enriched clusters demonstrated characteristic spatial distribution related to defect cluster distribution in each irradiated specimen.

XL-Calibur is a hard X-ray (15-80 keV) polarimetry mission operating from a stabilised balloon-borne platform in the stratosphere. It builds on heritage from the X-Calibur mission, which observed the accreting neutron star GX 301 - 2 from Antarctica, between December 29th 2018 and January 1st 2019. The XL-Calibur design incorporates an X-ray mirror, which focusses X-rays onto a polarimeter comprising a beryllium rod surrounded by Cadmium Zinc Telluride (CZT) detectors. The polarimeter is housed in an anticoincidence shield to mitigate background from particles present in the stratosphere. The mirror and polarimeter-shield assembly are mounted at opposite ends of a 12 m long lightweight truss, which is pointed with arcsecond precision by WASP – the Wallops Arc Second Pointer. The XL-Calibur mission will achieve a substantially improved sensitivity over X-Calibur by using a larger effective area X-ray mirror, reducing background through thinner CZT detectors, and improved anticoincidence shielding. When observing a 1 Crab source for tdaydays, the Minimum Detectable Polarisation (at 99% confidence level) is ∼2%·tday−1/2. The energy resolution at 40 keV is ∼5.9 keV. The aim of this paper is to describe the design and performance of the XL-Caliburmission, as well as the foreseen science programme.

Tungsten–tantalum (W-Ta) alloys containing 1–5%Ta were developed for fusion reactor applications. For the mechanical properties and resistance against recrystallization in the non-irradiated state, Ta-alloying improved the performance of W. Grain refining and solute Ta improved the recrystallization temperature and strength. In addition, W-1%Ta exhibited a superior ductility, including ductile-to-brittle transition temperature (DBTT), which might be attributed to the strength of sub-grain boundary. Proton irradiation study at 1500 °C to 0.5 dpa revealed a decrease in irradiation hardening (increase in hardness) in recrystallized specimens and a decrease in hardness reduction in as-received specimens with increasing Ta concentration. With respect to the high temperature irradiation of the as-received specimens, microstructural recovery followed by recrystallization could be one of the dominant factors affecting the hardness change. As a material performance required for the actual components of fusion reactors, resistance against high heat flux exposure have been studied through thermal shock tests. Thorough this experiment, it was clarified that the degradation by high heat flux exposure could be suppressed due to Ta-alloying.

We report the nucleotide sequence and genetic diversity of part of the envelope (env) gene of four strains of feline immunodeficiency virus (FIV) isolated from Argentine domestic cats. The DNA encoding the V3 to V5 regions of the env gene of the FIV isolates were amplified by PCR, cloned and sequenced. Phylogenetic analysis revealed that the Argentine isolates did not cluster into a single group; one isolate clustered with subtype B FIV isolated in the USA and Japan, whereas the others formed a new cluster of FIV which might represent a prototype sequence for subtype E.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTransferred nuclear Overhauser effect analyses of membrane-bound enkephalin analogs by proton nuclear magnetic resonance: correlation between activities and membrane-bound conformationsAlain Milon, Tatsuo Miyazawa, and Tsutomu HigashijimaCite this: Biochemistry 1990, 29, 1, 65–75Publication Date (Print):January 9, 1990Publication History Published online1 May 2002Published inissue 9 January 1990https://doi.org/10.1021/bi00453a009RIGHTS & PERMISSIONSArticle Views97Altmetric-Citations81LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

We determined a detailed conformation of the honeybee venom peptide melittin when bound to phosphatidylcholine vesicles using proton NMR. In the presence of vesicles of perdeuterated dipalmitoylglycerophosphocholine, two-dimensional transferred nuclear Overhauser enhancement (TRNOE) experiments were carried out. By a distance geometry calculation using NOE-derived distance constraints followed by a simulated annealing refinement, the N-terminal (Leu6-Leu10) and C-terminal (Leu13-Lys21) parts were found to have an alpha-helical conformation, whereas five C-terminal residues (Arg22-Gln26) did not show a unique conformation in the vesicle-bound state. The two alpha-helices were connected via a less structured segment (Thr11-Gly12) with a helix bend angle of 86 degrees +/- 34 degrees. Model distance geometry calculations using distance constraints extracted from a tetrameric melittin molecule in crystal assured us that the NOE constraints can accurately reproduce melittin's structure, as well as helping to interpret the NMR structures. Although the vesicle-bound conformation of melittin is similar to that occurring in a methanol solution and in dodecylphosphocholine micelles, significant differences were found in the conformation of C-terminal basic residues and the helix bend angle. This is the first study to clearly demonstrate conformation differences in micelle- and vesicle-bound peptides. In addition, lytic activity of melittin and its analogs showed better correlation with a peptide conformation in vesicles than in either methanol or micelles.

Abstract Structure of a mutagenic compound (Me-IQ) isolated from broiled fish was determined to be 2-amino-3,4-dimethylimidazo[4,5-f]quinoline based on the mass-, UV- and 1H-NMR-spectra and chemical synthesis. Me-IQ showed strong mutagenic activity towards Salmonella typhimurium TA98 in the presence of S-9 mix.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTwo tRNA1Ile species from an extreme thermophile, Thermus thermophilus HB8: effect of 2-thiolation of ribothymidine on the thermostability of tRNANobuyuki Horie, Miki Hara-Yokoyama, Shigeyuki Yokoyama, Kimitsuna Watanabe, Yoshiyuki Kuchino, Susumu Nishimura, and Tatsuo MiyazawaCite this: Biochemistry 1985, 24, 21, 5711–5715Publication Date (Print):October 1, 1985Publication History Published online1 May 2002Published inissue 1 October 1985https://doi.org/10.1021/bi00342a004RIGHTS & PERMISSIONSArticle Views92Altmetric-Citations59LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts Get e-Alerts

The carrier lifetime of ∼265 μm thick n-type 4H silicon carbide epilayers prepared using the carbon-implantation/annealing method was evaluated. An extraordinarily long minority carrier lifetime of 18.5 μs and a high injection lifetime of 19.2 μs were evaluated from time-resolved photoluminescence and microwave photoconductivity decay measurements, respectively. Based on the relationship between the epilayer thickness and carrier lifetime, the influence of surface recombination on the carrier lifetime was eliminated, and the bulk lifetime and hole diffusion constant were discussed.

Abstract The Raman and infrared spectra of isobutyl methyl sulfide and related alkyl sulfides were measured. The Raman spectra of the liquid, unannealed solid, and annealed solid of isobutyl methyl sulfide were compared and skeletal normal vibrations of possible rotational isomers were treated. Three rotational isomers were found to coexist in the liquid state whereas only one isomer was observed in the annealed solid. The energy differences among the three rotational isomers were measured. The correlations between the CH2–S stretching frequencies and molecular conformations were established, in common, for the molecules of isobutyl methyl sulfide, methyl propyl sulfide and ethyl methyl sulfide.

Journal of Polymer ScienceVolume 62, Issue 174 p. S62-S64 Letters to the editor Chain conformation and amide V band of polypeptides T. Miyazawa, T. Miyazawa Institute for Protein Research, Osaka University, Kitaku, Osaka, Japan (T.M. and K.F.) Department of Physics and Chemistry, Gakushuin University, Mejiro, Toshima, Tokyo, Japan (Y.M.)Search for more papers by this authorY. Masuda, Y. Masuda Institute for Protein Research, Osaka University, Kitaku, Osaka, Japan (T.M. and K.F.) Department of Physics and Chemistry, Gakushuin University, Mejiro, Toshima, Tokyo, Japan (Y.M.)Search for more papers by this authorK. Fukushima, K. Fukushima Institute for Protein Research, Osaka University, Kitaku, Osaka, Japan (T.M. and K.F.) Department of Physics and Chemistry, Gakushuin University, Mejiro, Toshima, Tokyo, Japan (Y.M.)Search for more papers by this author T. Miyazawa, T. Miyazawa Institute for Protein Research, Osaka University, Kitaku, Osaka, Japan (T.M. and K.F.) Department of Physics and Chemistry, Gakushuin University, Mejiro, Toshima, Tokyo, Japan (Y.M.)Search for more papers by this authorY. Masuda, Y. Masuda Institute for Protein Research, Osaka University, Kitaku, Osaka, Japan (T.M. and K.F.) Department of Physics and Chemistry, Gakushuin University, Mejiro, Toshima, Tokyo, Japan (Y.M.)Search for more papers by this authorK. Fukushima, K. Fukushima Institute for Protein Research, Osaka University, Kitaku, Osaka, Japan (T.M. and K.F.) Department of Physics and Chemistry, Gakushuin University, Mejiro, Toshima, Tokyo, Japan (Y.M.)Search for more papers by this author First published: December 1962 https://doi.org/10.1002/pol.1962.1206217424Citations: 57AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume62, Issue174December 1962Pages S62-S64 RelatedInformation

Journal of Polymer Science Part B: Polymer LettersVolume 1, Issue 7 p. 389-391 Article Cis-opening polymerization of propylene as revealed by infrared analyses of diisotactic poly(propylene-1d1) Tatsuo Miyazawa, Tatsuo Miyazawa Institute for Protein Research, Osaka University, Kitaku, Osaka, JapanSearch for more papers by this authorYoshiko Ideguchi, Yoshiko Ideguchi Institute for Protein Research, Osaka University, Kitaku, Osaka, JapanSearch for more papers by this author Tatsuo Miyazawa, Tatsuo Miyazawa Institute for Protein Research, Osaka University, Kitaku, Osaka, JapanSearch for more papers by this authorYoshiko Ideguchi, Yoshiko Ideguchi Institute for Protein Research, Osaka University, Kitaku, Osaka, JapanSearch for more papers by this author First published: July 1963 https://doi.org/10.1002/pol.1963.110010713Citations: 59AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References 1 Natta, G., M. Farina, and M. Peraldo, Chim. Ind. (Milan), 42, 255 (1960). 2 Natta, G., M. Farina, M. Peraldo, P. Corradini, G. Bressan, and P. Ganis, Atti Accad. Nazl. Lincei, Rend. Classe Sci. Fis. Mat. Nat., [8] 28, 442 (1960). 3 Natta, G., M. Farina, and M. Peraldo, Atti, Accad. Nazl. Lincei, Rend. Classe Sci. Fis. Mat. Nat., [8], 25, 424 (1958). 4 Peraldo, M., and M. Farina, Chim. Ind. (Milan), 42, 1349 (1960). 5 Miyazawa, T., J. Chem. Phys., 35, 693 (1963). 6 Miyazawa, T., Y. Ideguchi, and K. Fukushima, International Symposium on Molecular Structure and Spectroscopy, Tokyo, Japan, September, 1962; to be published in J. Chem. Phys. (May, 1963). 7 Miyazawa, T., K. Fukushima, and Y. Ideguchi, J. Polymer Sci., B1, 385 (1963). 8 Tasumi, M., T. Shimanouchi, H. Tanaka, and S. Ikeda, J. Polymer Sci., to be published. Citing Literature Volume1, Issue7July 1963Pages 389-391 ReferencesRelatedInformation

The general formulas of the G-matrix elements associated with internal-rotation coordinates are tabulated. The normal vibrations of the trans and gauche isomers of dichloroethane were treated by the use of the internal-rotation potential.

Abstract Infrared absorption and x‐ray diffraction measurements have been made of D , L ‐copoly‐γ‐benzylglutamate fibers (cast from dioxane solutions) with various D / L ratios and with various degrees of polymerization. It was found that each chain of these copolymers consists of a random coil portion and an α‐helix portion and that the conformation of the latter is similar to the α‐helix of pure poly‐γ‐benzyl‐ L ‐glutamate. It was also found that the fraction of the α‐helix portion increases with the degree of polymerization of the copolymer. A simplified polymerization mechanism has been proposed for mixtures of D ‐ and L ‐amino acid N ‐carboxyanhydrides. A model of the molecular conformation of the D , L ‐copolypeptide chains derived from this proposed polymerization mechanism is in good agreement with infrared, x‐ray, and other measurements. Based on the results of these observations, we discuss the number of L ‐ or D ‐residues linked in succession that is required for initiating the formation of an α‐helix during the course of polymerization.

The new Japanese x-ray astronomy satellite, ASTRO-H, will carry two identical hard x-ray telescopes (HXTs), which cover the energy range of 5 to 80 keV. The HXT mirrors employ tightly nested, conically approximated thin-foil Wolter-I optics, and the mirror surfaces are coated with Pt/C depth-graded multilayers to enhance the hard x-ray effective area by means of Bragg reflection. The HXT comprises foils 120–450 mm in diameter and 200 mm in length, with a focal length of 12 m. To obtain a large effective area, 213 aluminum foils 0.2 mm in thickness are tightly nested confocally. The requirements for HXT are a total effective area of >300  cm2 at 30 keV and an angular resolution of <1.7′ in half-power diameter (HPD). Fabrication of two HXTs has been completed, and the x-ray performance of each HXT was measured at a synchrotron radiation facility, SPring-8 BL20B2 in Japan. Angular resolutions (HPD) of 1.9′ and 1.8′ at 30 keV were obtained for the full telescopes of HXT-1 and HXT-2, respectively. The total effective area of the two HXTs at 30 keV is 349  cm2.

An optical packet and circuit integrated network (OPCInet) provides both high-speed, inexpensive services and deterministic-delay, low-data-loss services according to the users' usage scenarios, from the viewpoint of end users. From the viewpoint of network service providers, this network provides large switching capacity with low energy consumption, high flexibility, and efficient resource utilization with a simple control mechanism. This paper presents the recent progress made in the development of OPCInet and its extension to software-defined networking (SDN). We have developed OPCI nodes, which are capable of layer 3 switching from/to an Ethernet frame to/from an optical packet in the optical packet edge part and a burst-tolerant optical amplifier and an optical buffer with optical fiber delays in 100 Gbps optical packet switching part. The OPCI node achieves a packet error rate less than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> and is used as a node in a lab-network that has access to the Internet. A distributed automatic control works in a control plane for the circuit switching part and in a moving boundary control between optical packet resources and circuit resources. Our optical system for packet and circuit switching works with a centralized control mechanism as well as a distributed control mechanism. We have shown a packet-based SDN system that configures mapping between IP addresses and OPCI node identifiers and switching tables according to the requests from multiple service providers via a web interface.

Impacts of extended defects on performance and reliability of SiC power devices are reviewed. Threading dislocations in the state-of-the-art SiC wafers do not work as the major leakage paths and macroscopic defects generated during epitaxial process are more harmful. A basal plane dislocation is a killing defect in SiC bipolar devices because a Shockley-type stacking fault (SSF) is expanded from the dislocation when the electron-hole recombination energy is given. After classification of SSF-expansion patterns, the major types of SSFs (triangular-shaped and bar-shaped SSFs) and their origins are identified. Based on these understandings, two approaches to eliminate the “bipolar degradation” in SiC devices are presented. In particular, it is demonstrated that a “recombination-enhancing layer” is effective for substantial reduction of bipolar degradation in SiC devices.

The Raman and the infrared spectra of ethylene chlorhydrin have been remeasured with the result that the molecules take both the trans and the gauche forms in the gaseous and the liquid states, while they take only the gauche form in the solid state. By the measurement of the temperature dependence of the infrared absorption the energy difference between these two forms has been found as 0.95 kcal/mol.

Abstract To harness the synthetic power of modular polyketide synthases (PKSs), many aspects of their biochemistry must be elucidated. A robust platform to study these megadalton assembly lines has not yet been described. Here, we in vitro reconstitute the venemycin PKS, a short assembly line that generates an aromatic product. Incubating its polypeptides, VemG and VemH, with 3,5-dihydroxybenzoic acid, ATP, malonate, coenzyme A, and the malonyl-CoA ligase MatB, venemycin production can be monitored by HPLC and NMR. Multi-milligram quantities of venemycin are isolable from dialysis-based reactors without chromatography, and the enzymes can be recycled. Assembly line engineering is performed using pikromycin modules, with synthases designed using the updated module boundaries outperforming those using the traditional module boundaries by over an order of magnitude. Using combinations of VemG, VemH, and their engineered derivatives, as well as the alternate starter unit 3-hydroxybenzoic acid, a combinatorial library of six polyketide products is readily accessed.

The Japanese isolate (TM1 strain) of feline immunodeficiency virus (FIV) which replicates in a feline CD4 (fCD4)-positive lymphoblastoid cell line (MYA-1 cells) was molecularly cloned from extrachromosomal closed circular DNA. The restriction map of the clone, termed pFTM 191 complete genome (CG), showed a considerable difference from that of the U.S. isolate (Petaluma strain) of FIV. The sequence homology in the long terminal repeat between the TM1 and Petaluma strain was 82%. The pFTM 191 CG was biologically active after transfection into Crandell feline kidney cells which were permissive for replication of FIV Petaluma. However, the progeny virions could not reinfect fCD4-negative Crandell feline kidney cells but could infect fCD4-positive MYA-1 cells. When a specific-pathogen-free cat was inoculated with the virus derived from the pFTM 191 CG, the cat seroconverted within 8 weeks postinoculation and FIV was reisolated at 4, 8, and 20 weeks postinoculation. These results indicate the infectivity of the pFTM 191 CG in vivo.

Polysaccharides such as agar, guar gum, starch, and xylan were hydrolyzed to produce mono- and oligosaccharides under hydrothermal conditions with and without carbon dioxide in a small batch reactor. The molecular weight distributions of the polysaccharide hydrolyzates shifted to lower molecular weights by increasing the carbon dioxide load, corresponding to higher pressures of carbon dioxide. For example, the yield of glucose produced from the hydrolysis of starch at 200 degrees C was increased significantly from 3.7% to 53.0% (on a carbon weight basis) of the initial polysaccharide by increasing carbon dioxide load in a reaction time of 15 min. Carbonic acid generated from water and carbon dioxide appeared to lower the pH of high-temperature and high-pressure water. Polysaccharide hydrolysis under hydrothermal conditions in the presence of carbon dioxide is an environmentally benign method to produce mono- and oligosaccharides because the process does not require the use of conventional acids and bases followed by neutralization and separation.

The rates of migration of the aminoacyl group (transacylation) between 2'-O-(aminoacyl)-tRNA and 3'-O-(aminoacyl)-tRNA were studied by the nuclear magnetic resonance (NMR) analyses of 3'-terminal fragment models, with regard to the significance of transacylation in the process of protein biosynthesis. 2'(3')-O-L-Alanyladenosine, -valyladenosine, -isoleucyladenosine, -phenylalanyladenosine, and -methionyladenosine, and 2'(3')-O-L-phenylalanyladenosine 5'-phosphate and methionyladenosine 5'-phosphate were chemically synthesized, and the rates of transacylation in deuterated buffer were directly measured by the NMR saturation transfer method. The dependences of transacylation rates on p2H and temperature were analyzed. The results indicate that the transacylation rates are significantly affected by the ionization states of the alpha-amino group of the amino acid moiety but not by the presence of the 5'-phosphate group of the adenylate moiety. The second-order rate constants for the base-catalyzed transacylation reactions were also determined for the ionized form (with alpha-N2H3+ group) of (aminoacyl)adenosines. The transacylation rates of (aminoacyl)adenosines in 1H2O solution at p1H 7.3 and 37 degrees C (intracellular environment) were evaluated as 3-11 s-1 for the 2' leads to 3' transacylation and 1-4 s-1 for the 3' leads to 2' transacylation, indicating that the transacylation rate of free aminoacyl-tRNA is slower than the overall rate of polypeptide chain elongation per ribosome. This suggests the presence of some enzymatic factor for enhancing the transacylation rates of aminoacyl-tRNAs in the polypeptide chain elongation process in vivo.

Guar gum, a naturally occurring heteropolysaccharide made of mannose and galactose, was hydrolytically degraded without a catalyst in a batch reactor to produce water-soluble (WS) saccharides including mono- and oligosaccharides. The degradation was carried out under hydrothermal conditions over ranges of temperature from 180 to 240 °C and of reaction time from 3 to 60 min. Guar gum was readily dissolved and hydrolyzed, and the major products identified in the WS components were oligosaccharides with degrees of polymerization up to about 20, monosaccharides containing mannose and galactose, and 5-hydroxymethyl-2-furaldehyde (5-HMF). At 200 °C, the oligosaccharide yield, obtained from the difference between the yields of the total WS saccharides and monosaccharides, showed the highest value of 94.4% at 7 min among all conditions studied, on the basis of the saccharide content in the initial sample. The oligosaccharide yield decreased with reaction time, and the yield of monosaccharides correspondingly increased, and reached the highest value of 34.5% (mannose 22.8%, galactose 11.7%) at 60 min. The monosaccharides produced were further decomposed to secondary products such as 5-HMF. The maximum yield of 5-HMF obtained was 26.3% at 220 °C and 30 min. The production and the decomposition of galactose somewhat preceded those of mannose.

The 270‐MHz 1 H‐NMR spectra of mastoparan‐X, a tetradecapeptide toxin from hornet venom, have been observed in the presence of vesicles of perdeuterated dilauroylphosphatidylcholine ([ 2 H 64 ]DLPC). By the analysis of transferred nuclear Overhauser effects (TRNOE), the mastoparan‐X molecule as bound to [ 2 H 64 ]DLPC vesicles is found to take an α‐helical form in the C‐terminal (and central) part. The TRNOE analysis with perdeuterated phospholipid is a unique method for the elucidation of conformation of peptide (and drug) molecules as bound to phospholipid membranes.

The molecular conformations of naturally occurring 2-thiopyrimidine nucleosides (5-methylaminomethyl-2-thiouridine, 5-methoxycarbonylmethyl-2-thiouridine and 2-thiocytidine) and 5'-mononucleotides (5-methylaminomethyl-2-thiouridine 5'-monophosphate and 2-thiocytidine 5'-monophosphate) in 2H2O solution were elucidated by analyses of the proton NMR spin-coupling constant, nuclear Overhauser effect, and lanthanide-induced shifts and relaxation enhancements. As monomers, these nucleotides are almost exclusively in the 3E-gg-anti form, even in the absence of ordinary stabilizing factors of this form; i. e., base-stacking and base-pairing interactions with other nucleotide units. This inherent conformational rigidity of the 2-thiopyrimidine units probably contributes to stability of the conformation of tRNA.

Abstract Concentration and temperature dependences of the 1 H nmr spectra of N ‐acetyl‐ L ‐proline N ‐methylamide were observed in various solvents [CCl 4 , CDCl 3 , (CD 3 ) 2 CO, (CD 3 ) 2 SO, H 2 O, and D 2 O]. The fraction of the cis isomer (with respect to the bond between the acetyl carbonyl carbon and prolyl nitrogen atoms) depends greatly on the solvent used; the fraction of the cis isomer is higher in polar solvents than in nonpolar solvents. It depends also on concentration and temperature in nonpolar solvents but not in polar solvents. In nonpolar solvents the trans isomer mostly exists in the γ‐turn structure with an intramolecular hydrogen bond and the cis isomer tends to form molecular aggregates by intermolecular hydrogen bonds. In polar solvents both the cis and trans isomers exist in monomeric forms which interact with solvent molecules. The pH dependences of the N ‐methyl proton resonances indicate that the γ‐turn structure of the trans isomer is present also in aqueous solution, though its population is difficult to determine. Apparent enthalpy and entropy changes for the conversion of the trans isomer to cis isomer are evaluated for various solvents. The results are discussed in terms of the intra‐ and intermolecular hydrogen bondings.

1 H‐NMR analyses have been made on the conformations of 2‐thioribothymidine (s 2 T), 2‐thiodeoxyribothymidine (s 2 dT), as well as ribothymidine (T) and deoxyribothymidine (dT). s 2 T and s 2 dT exclusively take the anti form rather than the syn form. The C3'‐endo‐gg form of the sugar moiety is remarkably stabilized on modification of T to s 2 T, but not on modification of dT to s 2 dT. The steric effects of the 2‐thiocarbonyl group and the 2'‐hydroxyl group cause the rigidity of the C3'‐endo‐gg form of s 2 T. Such rigidity of s 2 T probably contributes to the thermostability of 2‐thiopyrimidine polyribonucleotides and extreme thermophile tRNAs.

The 270-MHZ nuclear magnetic resonance (NMR) spectra of erabutoxins a and b have been observed in 2H2O solution. By the use of convolution difference and double resonance techniques, proton signals in the aromatic and methyl regions have been assigned. From the pH dependence of NMR chemical shifts, the pKa value of His-26 of erabutoxin b is found to be 5.8, whereas His-7 of erabutoxins a and b is not protonated at pH above 3. The imidazole ring of His-7 is protonated upon the denaturation at pH 2.85. The acid denaturation process has been followed by the His-26 and methyl proton signals and is found to be reversible but is slow as compared with NMR chemical shift time scale. The circular dichroism (CD) of erabutoxin b has also been observed. The denaturation is found to involve a major change from the beta-rich conformation to a disordered one. The NMR and CD changes upon acid denaturation are satisfactorily explained by the two-state process. The deuterium exchange rates of the C-2 protons of His-26 and His-7 of erabutoxin b indicate that His-26 is exposed to the solvent whereas His-7 is tightly buried in the interior of the protein globule. The pKa value of Tyr-25 is as high as about 12.0, possibly due to the hydrogen bond formation between the hydroxyl group of Tyr-25 and a carboxylate group. The hydroxyl group of Tyr-25 is reversibly titrated so that this group is not buried tightly in the interior of the protein globule. The line width of the aromatic proton signals of Tyr-25 is significantly broad at room temperature, suggesting a restricted rotation of the aromatic ring. The aromatic proton signals of Trp-29 are fairly sharp; this aromatic ring is exposed and mobile. Except for His-7, the micro-environments of Tyr-25, His-26, and Trp-29 residues and methyl proton signals of valine and isoleucine are consistent with the locations of alpha carbon atoms as elucidated by X-ray crystal analyses.

A novel sesquiterpene, agelasidine-A possessing antispasmodic activity has been isolated from the sea sponge Agelas sp. and the structure has been determined on the basis of the spectral data and chemical degradation experiments.

Abstract Laser-excited Raman spectra of ethylene glycol have been measured in the liquid state for the temperature range of 20–100°C. From the temperature dependence of the Raman intensities, this molecule has been found to take both gauche and trans forms in the liquid state. The energy difference between the rotational isomers has been obtained to be H(trans)-H(gauche) = 0.71 ± 0.1 kcal mole from the intensity ratio of the trans Raman line at 481 cm−1 to the gauche Raman line at 523 cm−1. The result has been discussed in comparison with the rotational isomerism of other molecules of the XCH2-CH2Y type and with the chain conformation of poly (ethylene glycol).

We developed novel integrated optical packet and circuit switch-node equipment. Compared with our previous equipment, a polarization-independent 4 × 4 semiconductor optical amplifier switch subsystem, gain-controlled optical amplifiers, and one 100 Gbps optical packet transponder and seven 10 Gbps optical path transponders with 10 Gigabit Ethernet (10GbE) client-interfaces were newly installed in the present system. The switch and amplifiers can provide more stable operation without equipment adjustments for the frequent polarization-rotations and dynamic packet-rate changes of optical packets. We constructed an optical packet and circuit integrated ring network testbed consisting of two switch nodes for accelerating network development, and we demonstrated 66 km fiber transmission and switching operation of multiplexed 14-wavelength 10 Gbps optical paths and 100 Gbps optical packets encapsulating 10GbE frames. Error-free (frame error rate < 1×10(-4)) operation was achieved with optical packets of various packet lengths and packet rates, and stable operation of the network testbed was confirmed. In addition, 4K uncompressed video streaming over OPS links was successfully demonstrated.

Abstract The Raman spectra of the liquid, unannealed solid and annealed solid, and the infrared spectra of the gas, liquid, and annealed solid of ethyl methyl sulfide were measured. Normal vibrations were treated of the trans and gauche isomers. C–S stretching, CH2 rocking and skeletal deformation vibrations were discussed in relation with molecular structures. Only the gauche isomer was found to exist in the annealed solid. In the liquid state, the gauche isomer was found to be more stable, by 0.14±0.05 kcal/mol, than the trans isomer. The vibrational assignment made of ethyl methyl sulfide is consistent with those of related sulfides and disulfides.

Abstract Infrared spectra of polypeptides were measured in the region of 1800–400 cm −1 . For the α‐helical form, disordered form, and antiparallel‐chain β‐form, amide V band‐ arising from N‐H out‐of‐plane bending models were observed at 610–620, around 650, and 700–705 cm −1 , respectively, and amide V′ bands arising from N‐D out‐of‐plane bending modes were observed at 455–465, around 510, and a 515–530 cm −1 , respectively. These correlations are useful for conformation diagnoses, particularly for copolyamino‐acids or proteins which are not oriented. The nature of low‐frequency amide bands are discussed with reference to potential energy distributions calculated for the α‐helical form and β form.

Journal of Polymer Science Part B: Polymer LettersVolume 2, Issue 4 p. 395-397 Article Crystal vibrations, specific heat, and elastic moduli of the polyethylene crystal Tatsuo Miyazawa, Tatsuo Miyazawa Institute for Protein Research, Osaka University, Kitaku, Osaka, JapanSearch for more papers by this authorTeizo Kitagawa, Teizo Kitagawa Institute for Protein Research, Osaka University, Kitaku, Osaka, JapanSearch for more papers by this author Tatsuo Miyazawa, Tatsuo Miyazawa Institute for Protein Research, Osaka University, Kitaku, Osaka, JapanSearch for more papers by this authorTeizo Kitagawa, Teizo Kitagawa Institute for Protein Research, Osaka University, Kitaku, Osaka, JapanSearch for more papers by this author First published: April 1964 https://doi.org/10.1002/pol.1964.110020416Citations: 44AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat References 1 Wunderlich, B., J. Chem. Phys., 37, 1207, 1221 (1962); J. Polymer Sci., C1, 41 (1963). 2 Bunn, C. W., Trans. Faraday Soc., 35, 482 (1939). 3 Shimanouchi, T., J. Chem. Phys., 17, 243, 734, 848 (1949). 4 Tasumi, M., T. Shimanouchi, and T. Miyazawa, J. Mol. Spectr., 9, 261 (1962); J. Mol. Spectr., 11, 422 (1963); T. Miyazawa, J. Chem. Phys., 35, 693 (1961). 5 Stafford, S. J., H. R. Danner, and H. Boutin, J. Chem. Phys., 39, 1134 (1963). 6 Ito, T., and I. Sakurada, paper presented at Symposium on High Polymers, Osaka, 1962. Citing Literature Volume2, Issue4April 1964Pages 395-397 ReferencesRelatedInformation

ASTRO-H is an astrophysics satellite dedicated for non-dispersive X-ray spectroscopic study on selective celestial X-ray sources. Among the onboard instruments there are four Wolter-I X-ray mirrors of their reflectors’ figure in conical approximation. Two of the four are soft X-ray mirrors¹, of which the energy range is from a few hundred eV to 15 keV within the effective aperture being defined by the nested reflectors’ radius ranging between 5.8 cm to 22.5 cm. The focal point instruments will be a calorimeter (SXS) and a CCD camera (SXI), respectively. The mirrors were in quadrant configuration with photons being reflected consecutively in the primary and secondary stage before converging on the focal plane of 5.6 m away from the interface between the two stages. The reflectors of the mirror are made of heat-formed aluminum substrate of the thickness gauged of 152 &mu;m, 229 &mu;m, and 305 &mu;m of the alloy 5052 H-19, followed by epoxy replication on gold-sputtered smooth Pyrex cylindrical mandrels to acquire the X-ray reflective surface. The epoxy layer is 10 m nominal and surface gold layer of 0.2 &mu;m. Improvements on angular response over its predecessors, e.g. Astro-E1/Suzaku mirrors, come from error reduction on the figure, the roundness, and the grazing angle/radius mismatching of the reflecting surface, and tighter specs and mechanical strength on supporting structure to reduce the reflector positioning and the assembly errors. Each soft x-ray telescope (SXT), SXT-1 or SXT-2, were integrated from four independent quadrants of mirrors. The stray-light baffles, in quadrant configuration, were mounted onto the integrated mirror. Thermal control units were attached to the perimeter of the integrated mirror to keep the mirror within operating temperature in space. The completed instrument went through a series of optical alignment, thus made the quadrant images confocal and their optical axes in parallel to achieve highest throughput possible. Environmental tests were carried out, and optical quality of the telescopes has been confirmed. SXT-1 and -2 were tested with the broad but slightly divergent beam, up to 8 arc-minutes, at Goddard. The full characterization were carried out in Japan which includes: angular resolution, effective area in the energy range of ~ 0.4 – 12keV, off-axis response at various energies, etc. We report the calibration results of the SXT-1 and -2 that were obtained at NASA/Goddard and JAXA/ISAS. The detailed calibration are reported in the two papers in this conference: 9144-206, "Ground-based x-ray calibration of the ASTRO-H soft x-ray telescopes" by R. Iizuka et al. and 9144-207, "Revealing a detailed performance of the soft x-ray telescopes of the ASTRO-H mission" by T. Sato, et al. Some small but significant discrepancies existed between ISAS and Goddard measurements that were attributed to the difference of the X-ray beams - pencil beam vs divergent beam.

The impact of two post-growth processes, namely, C+-implantation/annealing process and thermal oxidation/annealing process, on trap concentrations in thick n-type 4H-SiC epilayers was studied for both Si- and C-face. Conditions such as the implantation dose and annealing temperature of the C+-implantation/annealing processes were optimized for Si-face epilayers, and consequently the Z1/2 center was eliminated up to 100 μm or more, and the minority carrier lifetime reached 13 μs while maintaining a good surface morphology. The effect of the process conditions on the creation of new traps, including ON1 center, was also studied in both Si- and C-face epilayers. The ON1 center was introduced in both Si- and C-face by two post-growth processes, although the concentration was found to vary according to the polar face and the post-growth processes. The mechanism of the different impacts on Z1/2 center reduction and ON1 center creation by the two post-growth processes on Si- and C-face is discussed.

ASTRO-H (Hitomi) is a Japanese X-ray astrophysics satellite just launched in February, 2016, from Tanegashima, Japan by a JAXA's H-IIA launch vehicle. It has two Soft X-ray Telescopes (SXTs), among other instruments, that were developed by NASA's Goddard Space Flight Center in collaboration with ISAS/JAXA and Nagoya University. One is for an X-ray micro-calorimeter instrument (Soft X-ray Spectrometer, SXS) and the other for an X-ray CCD camera (Soft X-ray Imager, SXI), both covering the X-ray energy band up to 15 keV. The two SXTs were fully characterized at the 30-m X-ray beamline at ISAS/JAXA. The combined SXT+SXS system effective area is about 250 and 300 cm² at 1 and 6 keV, respectively, although observations were performed with the gate valve at the dewar entrance closed, which blocks most of low energy X-rays and some of high energy ones. The angular resolution for SXS is 1.2 arcmin (Half Power Diameter, HPD). The combined SXT+SXI system effective area is about 370 and 350 cm² at 1 and 6 keV, respectively. The angular resolution for SXI is 1.3 arcmin (HPD). The both SXTs have a field of view of about 16 arcmin (FWHM of their vignetting functions). The SXT+SXS field of view is limited to 3 x 3 arcmin by the SXS array size. In-flight data available to the SXT team was limited at the time of this conference and a point-like source data is not available for the SXT+SXS. Although due to lack of attitude information we were unable to reconstruct a point spread function of SXT+SXI, according to RXJ1856.5-3754 data, the SXT seems to be working as expected in terms of imaging capability. As for the overall effective area response for both SXT+SXS and SXT+SXI, consistent spectral model fitting parameters with the previous measurements were obtained for Crab and G21.5-0.9 data. On the other hand, their 2-10 keV fluxes differ by about 20% at this point. Calibration work is still under progress. The SXT is the latest version of the aluminum foil X-ray mirror, which is extremely light-weight and very low cost, yet produces large effective area over a wide energy-band. Its area-mass ratio is the largest, 16 cm²/kg, among ASTRO-H, Chandra, and XMM-Newton mirrors. The aluminum foil mirror is a still compelling technology depending on the mission science goal.

The United States and Japan have collaborated on fusion materials research in a series of agreements reaching back to 1981. The PHENIX collaboration is the latest U.S.-Japan project which spans 2013 to 2019 and has the goal of assessing technical feasibility of tungsten-based, helium-cooled plasma-facing component concepts for a demonstration fusion power reactor (DEMO). Task 2 within the PHENIX project is focused on evaluating the neutron irradiation effects in tungsten. For tungsten, the transmutation to Re and Os is at least as important to determining its properties after irradiation as the displacement damage, and the transmutation rate depends on the energy spectrum of the reactor. A large-scale, instrumented irradiation capsule with thermal neutron shielding to better mimic fusion conditions was irradiated in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. The tungsten specimens were irradiated in different temperature zones between 500°C and 1200°C to doses of ~0.2 to 0.7 displacements per atom. More than 20 varieties of pure tungsten and tungsten alloys were included in the irradiation, and they were evaluated in the 3025E hot-cell facility and at the Low Activation Materials Development and Analysis Laboratory. The elevated temperature tensile, fracture toughness, hardness, thermal conductivity, electrical resistivity, density, elemental composition, and microstructure properties of the irradiated materials are being collected. This paper overviews the experimental design, specimen matrix, and the initial results of postirradiation examinations.

Low temperature brittleness and high ductile-to-brittle transition temperature (DBTT) are potential drawbacks related to the mechanical properties of tungsten (W) for divertor application in fusion reactors. In the present study, to improve the mechanical properties of W, rhenium (Re) addition has been applied as a solid solution alloying method. In this paper, the effects of Re addition on the tensile and Charpy impact properties of W thick plate fabricated by powder metallurgy and hot rolling were investigated, which has enough volume as the plasma facing material and the microstructural uniformity for mass-production. At the temperature below 1000 °C, the W-3%Re showed 5–30% higher strength, 10–35% higher total elongation, 100 °C lower DBTT, and 16% higher upper shelf energy than those of the pure W.

Neutron irradiation effects on the tensile properties of Pure W, K-doped W, W–3%Re, and K-doped W–3%Re were examined under the US-Japan collaboration project PHENIX. The fission neutron irradiation experiments were carried out up to 0.74 dpa at 600 °C and 800 °C. Pure W (SR) showed irradiation hardening and loss of ductility after irradiation at 600 °C and 800 °C. K-doped W–3%Re (SR) also exhibited irradiation hardening but was ductile after irradiation. Characteristic points of the K-doped W–3%Re (SR) are small grain size and layered structure. The stress-relief treatment and the layered structure may improve the ductility of powder-metallurgy W alloys after neutron irradiation, so a combination of K-doping and Re addition would be beneficial to improve irradiation resistance.