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101.
Optical Review - As part of our ongoing research on lensless imaging with a Fresnel zone aperture (FZA), we propose a method of improving resolution with higher FZA harmonics. Although previous... 相似文献
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A full and consecutive analysis of the dynamic and thermodynamic properties of an ideal gas of relativistic particles with Lorentz?CEinstein dispersion law and arbitrary number of translational degrees of freedom is carried out. Gibbs statistical mechanics is used along with Bogolyubov??s concept of quasiaverages and the generalized version of the Bogolyubov?CZubarev theorem in the classical regime well beyond the temperature of the quantum degeneracy. General expressions for a pair of equations of state, namely thermic (for the pressure) and caloric (for the inner energy) are found; the fluctuations of these quantities are also found: the compressibility and heat capacity, respectively. All expressions are found in closed form and studied in low- and high-temperature limits. 相似文献
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Nitrogen-doped NaTaO3 was synthesized through 1-pot reaction, hydrothermal process using Ta3N5 as precursor. Changing concentration and amount of NaOH aqueous solution influenced nitrogen content in NaTaO3. Absorption edge of nitrogen-doped NaTaO3 was extended at 570 nm, and absorbance in visible light region depended on nitrogen content in NaTaO3. Anodic photocurrent measured under visible light irradiation became larger with increasing nitrogen content in NaTaO3-xNy. Under ultraviolet light irradiation (λ ≤ 400 nm), the highest anodic photocurrent was observed when nitrogen concentration was y = 0.024. It was possible to expand the wavelength range that can be effectively utilized for the photoelectrochemical reaction. 相似文献
107.
In order to elucidate the characteristic features of commercial methylcellulose precisely, O-methylcellulose model copolymers consisting of 2,3,6-tri-O-methylanhydroglucose unit (236MeAGU) and 2-O-methylanhydroglucose unit (2MeAGU) with various composition ratios were synthesized via cationic ring-opening copolymerization
of the corresponding glucose orthoester derivatives, subsequent removal of pivaloyl and allyl groups, and methylation. The
structure of the obtained copolymers was confirmed by 1H-, 13C-NMR, and FT-IR. Temperature-dependent turbidity measurement verified their thermoresponsive behavior in aqueous solution.
The lower critical solution temperature was tuned from 63 to 45 °C above 47 mol-% 236MeAGU content. The hydrophobicity along
the cellulose chain was dominant to determine their physical properties. However, the aqueous properties of the MC model copolymers
were strongly affected by the slight difference of the composition ratio. The present method would provide further details
of the structure–property relationship of O-methylcellulose. 相似文献
108.
Solid-phase oligopeptide synthesis has been well developed and most short oligopeptides can now be easily synthesized. However, when a desired oligopeptide forms a secondary structure or includes less reactive amino acids such as aminoisobutyric acid, its terminal amino groups become less reactive and synthesis of the desired oligopeptides becomes difficult. To expand the number of synthetic peptide sequences, we have developed efficient coupling conditions using 3-nitro-l,2,4-triazol-l-yl-tris(pyrrolidin-1-yl)phosphonium hexafluorophosphate (PyNTP) as a highly reactive condensing reagent on an unswellable solid support. PyNTP demonstrated higher reactivity than conventional condensing reagents and the optical purity of the synthesized oligopeptides was sufficiently high for application to general oligopeptide synthesis. 相似文献
109.
Joshua Kyle Stanfield Keita Omura Ayaka Matsumoto Chie Kasai Hiroshi Sugimoto Yoshitsugu Shiro Yoshihito Watanabe Osami Shoji 《Angewandte Chemie (International ed. in English)》2020,59(19):7611-7618
Despite CYP102A1 (P450BM3) representing one of the most extensively researched metalloenzymes, crystallisation of its haem domain upon modification can be a challenge. Crystal structures are indispensable for the efficient structure‐based design of P450BM3 as a biocatalyst. The abietane diterpenoid derivative N‐abietoyl‐l ‐tryptophan (AbiATrp) is an outstanding crystallisation accelerator for the wild‐type P450BM3 haem domain, with visible crystals forming within 2 hours and diffracting to a near‐atomic resolution of 1.22 Å. Using these crystals as seeds in a cross‐microseeding approach, an assortment of P450BM3 haem domain crystal structures, containing previously uncrystallisable decoy molecules and diverse artificial metalloporphyrins binding various ligand molecules, as well as heavily tagged haem‐domain variants, could be determined. Some of the structures reported herein could be used as models of different stages of the P450BM3 catalytic cycle. 相似文献
110.
Hiroyuki Kataoka Tsutomu Inoue Natsuki Ikekita Keita Saito 《Analytical and bioanalytical chemistry》2014,406(8):2171-2178
Heterocyclic amines (HCAs) formed in cooked meats and fish are mutagens and carcinogens in rodents and nonprimates. Exposure to HCAs may also be a risk factor for human tumors, but the association between dietary intake and human cancer risk has not been determined. To assess recent exposure to HCAs, we developed a simple and sensitive method for measuring HCAs in urine by automated on-line in-tube solid-phase microextraction (SPME) using a Supel-Q PLOT capillary column as an extraction device, in combination with liquid chromatography–tandem mass spectrometry (LC–MS/MS). Thirteen HCAs were separated within 15 min using a ZORBAX Eclipse XDB-C8 column and detected selectively by multiple reaction monitoring using MS/MS. This method can be applied easily to the analysis of small amounts of urine samples without any other pretreatment except for alkaline hydrolysis of bound forms of HCAs. The quantification limits of HCAs in 0.2 mL of urine samples were about 1.7–4.1 pg/mL (S/N?=?10). Using this method, we evaluated the exposure to HCAs in persons who consumed well-done pan-fried beef and the suitability of using urinary HCAs as exposure biomarkers. We also analyzed the ability of vegetable consumption to prevent carcinogenic risks from exposure to HCAs by measuring free and bound forms of HCAs in urine. Figure
Mutagenic and carcinogenic heterocyclic amines are ingested from cooked foods and cigarette smoke, formed metabolites and adducts in target tissue, and excreted in urine and feces 相似文献