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51.
Sai Venkatesh Pingali Hugh M. O’Neill Yoshiharu Nishiyama Lilin He Yuri B. Melnichenko Volker Urban Loukas Petridis Brian Davison Paul Langan 《Cellulose (London, England)》2014,21(2):873-878
Morphological changes to the different components of lignocellulosic biomass were observed as they occurred during steam pretreatment by placing a pressure reaction cell in a neutron beam and collecting time-resolved neutron scattering data. Changes to cellulose morphology occurred mainly in the heating phase, whereas changes in lignin morphology occurred mainly in the holding and cooling phases. During the heating stage, water is irreversibly expelled from cellulose microfibrils as the elementary fibrils coalesce. During the holding phase lignin aggregates begin to appear and they increase in size most noticeably during the cooling phase. This experiment demonstrates the unique information that in situ small angle neutron scattering studies of pretreatment can provide. This approach could be useful in optimizing the heating, holding and cooling stages of pretreatments to allow the exact size and nature of lignin aggregates to be controlled in order to enhance enzyme accessibility to cellulose and therefore the efficiency of biomass conversion. 相似文献
52.
Pan Chen Yoshiharu Nishiyama Jean-Luc Putaux Karim Mazeau 《Cellulose (London, England)》2014,21(2):897-908
We have performed molecular dynamics calculations using a revised version of the Gromos56Acarbo force field to understand the consequences of the different potential hydrogen bonding patterns on the structural stability and thermal behavior of the Iα and Iβ forms of native cellulose. For each allomorph, we considered three patterns of hydrogen bonds: two patterns obtained from neutron diffraction data refinement and a regular mixture of the two. Upon annealing, the hydrogen bonding schemes of cellulose Iβ, irrespective of the starting structure, re-arranged into the main hydrogen bond pattern experimentally observed (pattern A). On the other hand, the Iα structures, irrespective of the starting hydrogen bonding pattern, converged to a non-experimental structure where the adjacent chains are shifted along the chain direction by 0.12 nm in the hydrogen-bonded plane, and the hydroxymethyl group conformation alternates between gt and tg along the chain. The exotic structure in Iα might be a consequence of a deficiency in force field parameters and/or potential molecular arrangement in less crystalline cellulose. 相似文献
53.
Takeshi Kimura Yukiko Izumi Naomichi Furukawa Yoshihiro Minoshima 《Heteroatom Chemistry》1996,7(2):143-147
1,1-Dimethyldibenzo[bc,fg][1,4]silathiapentalene ( 1a ) was prepared by treatment of 1,9-bis(methyl-sulfinyl)dibenzothiophene with EtMgBr or of dibenzothiophene with n-butyllithium, and then with dimethyl dichlorosilane. The structure of 4,4-dimethyl-dibenzo[bc,fg][1,4]silathiapentalene 1-oxide ( 2 ), obtained by oxidation of compound 1a with mCPBA, was determined by X-ray crystallographic analysis. The structure of compound 2 determined experimentally was compared to the structure obtained by semiempirical molecular orbital calculations (AM1). The MO calculations of compound 1a and its phenyl analog 1b were also performed by AM1 to evaluate their structures. © 1996 John Wiley & Sons, Inc. 相似文献
54.
Yoshiharu Kagami Jian Ping Gong Yoshihito Osada 《Macromolecular rapid communications》1996,17(8):539-543
Shape memory polymers were prepared by copolymerizing stearyl acrylate and methyl acrylate. The principle of this shape memory effect is based on reversible order-disorder transition of crystalline aggregates of stearyl moieties. A specific feature of this type of shape memory copolymer is that the transition temperature at which the polymer abruptly becomes soft and deforms can be controlled by changing the monomer composition, which enables one to adjust the shape memory effect at a desired temperature. Mechanism and process of the shape memory behaviors were discussed. 相似文献
55.
Shigeyoshí Nishino Yasuhiro Nagato Yoshihiro Hasegawa Hisanao Yamamoto Kazuo Kamaike Yoshiharu Ishido 《Heteroatom Chemistry》1991,2(1):187-196
Reagent systems of sodium– and tetrabutylammonium nitrite–acetic anhydride were proved to be extremely efficient for the deanilidation of nucleoside 3′-phosphoranilidates, whose reactions were rapid with the former and instant with the latter. It was further found that the reagent system is applicable to oligonucleotide synthesis provided that the exocyclic amino groups of 2′-deoxyadenosine, 2′-deoxyguanosine, and 2′-deoxycytidine were protected by succinylation. 相似文献
56.
Yukiko Yasuoka Yuichiro Izumi Takashi Fukuyama Haruki Omiya Truyen D. Pham Hideki Inoue Tomomi Oshima Taiga Yamazaki Takayuki Uematsu Noritada Kobayashi Yoshitaka Shimada Yasushi Nagaba Tetsuro Yamashita Masashi Mukoyama Yuichi Sato Susan M. Wall Jeff M. Sands Noriko Takahashi Katsumasa Kawahara Hiroshi Nonoguchi 《Molecules (Basel, Switzerland)》2022,27(3)
Anemia is a major complication of chronic renal failure. To treat this anemia, prolylhydroxylase domain enzyme (PHD) inhibitors as well as erythropoiesis-stimulating agents (ESAs) have been used. Although PHD inhibitors rapidly stimulate erythropoietin (Epo) production, the precise sites of Epo production following the administration of these drugs have not been identified. We developed a novel method for the detection of the Epo protein that employs deglycosylation-coupled Western blotting. With protein deglycosylation, tissue Epo contents can be quantified over an extremely wide range. Using this method, we examined the effects of the PHD inhibitor, Roxadustat (ROX), and severe hypoxia on Epo production in various tissues in rats. We observed that ROX increased Epo mRNA expression in both the kidneys and liver. However, Epo protein was detected in the kidneys but not in the liver. Epo protein was also detected in the salivary glands, spleen, epididymis and ovaries. However, both PHD inhibitors (ROX) and severe hypoxia increased the Epo protein abundance only in the kidneys. These data show that, while Epo is produced in many tissues, PHD inhibitors as well as severe hypoxia regulate Epo production only in the kidneys. 相似文献
57.
Toshihiro Okajima Hiroyuki Setoyama Marek Brancewicz Masahide Kawamoto Yoshiharu Sakurai 《X射线光谱测定》2020,49(3):390-397
X-ray fluorescence spectra of copper (Cu) metal, copper monoxide (CuO), and potassium chromate (K2CrO4) were recorded as a function of incident X-ray energy near the Cu K-edge and chromium (Cr) K-edge, respectively, using a conventional silicon drift detector. The spectra contained components due to elastic, inelastic, and multiple scattering, in addition to the Kα and Kβ lines. Cu and Cr K-edge X-ray absorption fine structure (XAFS) spectra of Cu, CuO, and K2CrO4 were obtained by an intensity analysis of the Kα and Kβ lines. The intensity of the Kβ line for the different incident photon energies was obtained by numerically removing the additional scattering components using the MUSCAT program. These spectra exhibited a jump near the K absorption edges, which reproduced the spectral features obtained in transmission mode for both Cu, CuO, and K2CrO4. A chemical shift was also clearly identified in the X-ray absorption near edges structure using the X-ray fluorescence Kβ line. In addition, the Cr K-edge extended XAFS spectrum of K2CrO4 was clearly observed using the Cr Kβ fluorescent line. The XAFS measurements on the Kα and Kβ lines are possible, and they carry equally valuable information. 相似文献
58.
Yusuke Sasano Shota Nagasawa Mai Yamazaki Dr. Masatoshi Shibuya Prof. Dr. Jaiwook Park Prof. Dr. Yoshiharu Iwabuchi 《Angewandte Chemie (International ed. in English)》2014,53(12):3236-3240
The direct oxidation of unprotected amino alcohols to their corresponding amino carbonyl compounds has often posed serious challenges in organic synthesis and has constrained chemists to adopting an indirect route, such as a protection/deprotection strategy, to attain their goal. Described herein is a highly chemoselective aerobic oxidation of unprotected amino alcohols to their amino carbonyl compounds in which 2‐azaadamantane N‐oxyl (AZADO)/copper catalysis is used. The catalytic system developed leads to the alcohol‐selective oxidation of various unprotected amino alcohols, carrying a primary, secondary, or tertiary amino group, in good to high yield at ambient temperature with exposure to air, thus offering flexibility in the synthesis of nitrogen‐containing compounds. 相似文献
59.
A high‐performance liquid chromatography assay with a triazole‐bonded column for evaluation of d‐amino acid oxidase activity 下载免费PDF全文
Megumi Iwasaki Yoshiyuki Kashiwaguma Chihiro Nagashima Mao Izumi Ayano Uekusa Sumiko Iwasa Mayu Onozato Hideaki Ichiba Takeshi Fukushima 《Biomedical chromatography : BMC》2016,30(3):384-389
Elution profiles of kynurenic acid (KYNA) and 7‐chlorokynurenic acid (Cl‐KYNA) were examined by high‐performance liquid chromatography (HPLC) using a triazole‐bonded stationary phase column (Cosmosil® HILIC) under isocratic elution of a mobile phase consisting of CH3CN–aqueous 10 mm ammonium formate between pH 3.0 and 6.0. The capacity factors of KYNA and Cl‐KYNA varied with both the CH3CN content and the pH of the mobile phase. The elution order of KYNA and Cl‐KYNA was reversed between the CH3CN‐ and H2O‐rich mobile phases, suggesting that hydrophilic interactions and anion‐exchange interactions caused retention of KYNA and Cl‐KYNA in the CH3CN‐ and H2O‐rich mobile phases, respectively. The present HPLC method using a triazole‐bonded column and fluorescence detection (excitation 250 nm, emission 398 nm) was applied to monitor in vitro production of KYNA from d ‐kynurenine (d ‐KYN) by d ‐amino acid oxidase (DAO) using Cl‐KYNA as an internal standard. A single KYNA peak was clearly observed after enzymatic reaction of d ‐KYN with DAO. Production of KYNA from d ‐KYN was suppressed by the addition of commercial DAO inhibitors. The present HPLC method can be used to evaluate DAO activity and DAO inhibitory effects in candidate drugs for the treatment of schizophrenia. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
60.