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91.
A highly sensitive assay for tyrosine hydroxylase (TH) activity by high-performance liquid chromatography (HPLC) with amperometric detection was devised based on the rapid isolation of enzymatically formed DOPA by a double-column procedure, the columns fitted together sequentially (the top column of Amberlite CG-50 and the bottom column of aluminium oxide). DOPA was adsorbed on the second aluminium oxide column, then eluted with 0.5 M hydrochloric acid, and assayed by HPLC with amperometric detection. D-Tyrosine was used for the control. alpha-Methyldopa was added to the incubation mixture as an internal standard after incubation. This assay was more sensitive than radioassays and 5 pmol of DOPA formed enzymatically could be measured in the presence of saturating concentrations of tyrosine and 6-methyltetrahydropterin. The TH activity in 2 mg of human putamen could be easily measured, and this method was found to be particularly suitable for the assay of TH activity in a small number of nuclei from animal and human brain. 相似文献
92.
A multiscale model was proposed in a companion paper for assessing the impact of bacterial growth attached to soil particles on the intrinsic permeability of soil. In this paper, this model is used to simulate a column experiment. The simulation conditions are described and the results of the simulation runs are presented. Various possible explanations for the observed reduction in permeability in the column experiment are analyzed using the model and it is concluded that the reduction in the metabolic activity of the attached biomass at the bottom of the column is mainly responsible for the reduction in the intrinsic permeability near the top of the column. Based on the set of parameter values used in the simulations, upper and lower bounds on the reduction in metabolic activity are estimated. 相似文献
93.
H. Kudo S. Sudo T. Oka Y. Hama A. Oshima M. Washio T. Murakami 《Radiation Physics and Chemistry》2009,78(12):1067-1070
Ion-beam irradiation effects on polyimide, Kapton™, were studied with respect to optical and electronic properties. Stack films of Kapton™ (12.5 μm thick) were irradiated to various ion beams in air or vacuo at room temperature and subjected to ultraviolet–visible (UV–vis) spectroscopy, and change in absorbance and energy gap is discussed. The UV–vis absorption spectrum, which is assigned to the transition of electrons in benzene rings from π to π* orbital, upon He2+ (6 MeV/u) irradiation in air, shifted towards longer wavelength direction for all cases, and the shift was more obvious for higher linear energy transfer (LET) ion beams. The energy gap of the transition was estimated, and the H+ and He2+ ion beams caused little change in the transition energy gap Eg, while the heavier ions such as C6+ and Si14+ caused more significant decrease. This decrease is assumed to the structural changes around benzene rings, and the infrared spectroscopy revealed breakage in imide groups next to benzene ring in the repeating unit of polyimide. 相似文献
94.
Jin Y Hada N Oka J Kanie O Daikoku S Kanie Y Yamada H Takeda T 《Chemical & pharmaceutical bulletin》2006,54(4):485-492
Stereocontrolled syntheses of model compounds related to a major antigenic epitope against antibupleurum 2IIc/PG-1-IgG from antiulcer pectic polysaccharide are described. A trisaccharide derivative (13) was prepared as a precursor and a novel and simple approach for the rational design of a glycocluster and glycodendrimer was developed, through the syntheses of the fluorescence-labeled glycocluster (2) and glycodendrimer (3). 相似文献
95.
Ito Y Goto T Yamada S Matsumoto H Oka H Takahashi N Nakazawa H Nagase H Ito Y 《Journal of chromatography. A》2006,1108(1):20-25
Dual counter-current chromatography (dual CCC) has been successfully applied to rapid sample preparation for the simultaneous determination of residual carbaryl, fenobucarb and methomyl in vegetable oil and citrus fruit. The citrus fruit samples were extracted with n-hexane solution containing stable isotopically labeled internal standards (methomyl-d3, fenobucarb-d3 and carbaryl-d9), and applied to dual CCC using a two-phase solvent system of n-hexane-acetonitrile to purify the carbamate pesticides from aliphatic sample matrix. The coiled column was rotated at 420 rpm, the lower mobile phase was introduced through the head toward the tail, and the upper mobile phase in the opposite direction. Due to the high partition efficiency of dual CCC, the lower phase fraction collected from 2 to 5 min after injection could be subjected to flow-injection tandem mass spectrometry directly after concentration. Repetitive sample injection can be performed at high reproducibility without a risk of contamination from the compounds retained in the column. 相似文献
96.
Kuramitsu Y Harada T Takashima M Yokoyama Y Hidaka I Iizuka N Toda T Fujimoto M Zhang X Sakaida I Okita K Oka M Nakamura K 《Electrophoresis》2006,27(8):1651-1658
Hepatocellular carcinoma (HCC) is one of the most common fatal cancers, and chronic infection with hepatitis C virus (HCV) is thought to be one of the main causes in Japan. To identify diagnostic or therapeutic biomarkers for HCC associated with HCV (HCV-HCC), we tried to elucidate the factors related to the products from cancerous tissues of HCV-infected patients. From proteomic differential display analysis of liver tissue samples from HCV-HCC cancerous tissues and corresponding non-cancerous tissues from patients, three protein spots of the same molecular mass (42 kDa), whose expression increased in well-differentiated cancerous tissues, were detected. Although their pI were different, they were identified as glutamine synthetase (GS) by PMF with MALDI-TOF MS and by Western blotting using anti-GS specific mAb. Immunohistochemical analysis showed that tumor tissue consists of two parts, GS-positive cell and GS-negative cell regions, suggesting that GS-producing cells grew in the tumor tissue as a nodule in nodules. The tryptic peptides of the most acidic GS isoform lost the signal of 899.5 Da, corresponding a peptide of SASIRIPR, and gained a signal of 1059.5 Da, which was submitted to PSD analysis. PSD analysis showed the neutral loss by elimination of two phosphate groups, supposed to be on serine residues of the 899.5-Da peptide, from serine 320 to arginine 327 in GS. PMF followed by PSD analysis is thought to be useful for the determination of phosphorylation sites of proteins showing molecular heterogeneity. 相似文献
97.
A high birefringence of over 0.21 for the yttrium vanadate (YVO4) crystal in the middle wavelength infrared (i.e., 3-5 microm) was measured. A Fourier transform infrared spectrometer was employed in the channel spectra technique to obtain the measurements. 相似文献
98.
A novel method to stabilize a channeled spectropolarimeter is described. The fluctuating retardations of the high-order retarders used in the spectropolarimeter are calibrated in parallel to the measurement of the wavenumber-dependent state of polarization (SOP) of light. Both the calibration of the retarders and the measurement of the SOP can be made simultaneously using a single light to be measured, and hence the resultant wavenumber-dependent SOP is almost immune to fluctuation of the retardations. The effectiveness of this method is experimentally demonstrated with retardation fluctuations induced by a temperature change up to 40 degrees C. 相似文献
99.
Jie Yang Toshihide Oka Zheng Li HuaiXin Yang JianQi Li GenFu Chen Guo-Qing Zheng 《中国科学:物理学 力学 天文学(英文版)》2018,(11)
We report~(75) As nuclear magnetic resonance(NMR)/nuclear quadrupole resonance(NQR) and transmission electron microscopy(TEM) studies on LaFeAsO_(1-x)F_x. There are two superconducting domes in this material. The first one appears at 0.03 ≤ x ≤0.2 with T_c~(max) = 27 K, and the second one at 0.25 ≤x≤0.75 with T_c~(max) = 30 K. By NMR and TEM, we demonstrate that a C4-to-C2 structural phase transition(SPT) takes place above both domes, with the transition temperature T_s varying strongly with x. In the first dome, the SPT is followed by an antiferromagnetic(AF) transition, but neither AF order nor low-energy spin fluctuations are found in the second dome. By ~(75) As nuclear spin-lattice relaxation rate(1/T_1) measurements, we find that AF order and superconductivity coexist microscopically in LaFeAsO_(0.97) F_(0.03). In the coexisting region, 1/T_1 decreases at T_c but becomes proportional to T below 0.6 T_c, indicating gapless excitations. Therefore, in contrast to the early reports, the obtained phase diagram for x ≤ 0.2 is quite similar to the doped BaFe_2As_2 system. The electrical resistivity p in the second dome can be fitted by ρ = ρ0 + AT~n with n = 1 and a maximal coefficient A at around xopt = 0.5-0.55 at which T_s extrapolates to zero and Tc is the maximal, which suggests the importance of quantum critical fluctuations associated with the SPT. We have constructed a complete phase diagram of LaFeAsO_(1-x)F_x, which provides insight into the relationship between SPT, antiferromagnetism and superconductivity. 相似文献
100.
Haruka Kawade Jyoji Morise Sushil K. Mishra Shuta Tsujioka Shogo Oka Yasuhiko Kizuka 《Molecules (Basel, Switzerland)》2021,26(17)
Human natural killer—1 (HNK-1) is a sulfated glyco-epitope regulating cell adhesion and synaptic functions. HNK-1 and its non-sulfated forms, which are specifically expressed in the brain and the kidney, respectively, are distinctly biosynthesized by two homologous glycosyltransferases: GlcAT-P in the brain and GlcAT-S in the kidney. However, it is largely unclear how the activity of these isozymes is regulated in vivo. We recently found that bisecting GlcNAc, a branching sugar in N-glycan, suppresses both GlcAT-P activity and HNK-1 expression in the brain. Here, we observed that the expression of non-sulfated HNK-1 in the kidney is unexpectedly unaltered in mutant mice lacking bisecting GlcNAc. This suggests that the biosynthesis of HNK-1 in the brain and the kidney are differentially regulated by bisecting GlcNAc. Mechanistically, in vitro activity assays demonstrated that bisecting GlcNAc inhibits the activity of GlcAT-P but not that of GlcAT-S. Furthermore, molecular dynamics simulation showed that GlcAT-P binds poorly to bisected N-glycan substrates, whereas GlcAT-S binds similarly to bisected and non-bisected N-glycans. These findings revealed the difference of the highly homologous isozymes for HNK-1 synthesis, highlighting the novel mechanism of the tissue-specific regulation of HNK-1 synthesis by bisecting GlcNAc. 相似文献