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811.
胸腺肽α1(Thymosinα1)是一种由28个氨基酸组成的新型免疫调节因子,它可以启动T淋巴细胞的成熟、刺激分泌干扰素及各种淋巴介素,以及增强自然杀伤细胞介导的细胞毒性。临床应用范围较为广泛,主要用于治疗恶性肿瘤所致的免疫功能低下,乙型、丙型肝炎及其并发症和严重感染或抗生素不能有效控制的感染等,具有广阔的应用前景。由于该药物人体用药后浓度低,仅为ng级,为了满足临床药代动力学的要求,本文将高分辨的QSTAR和API-3000LC-MS-MS相结合,对人血浆中胸腺肽α1含量的质谱定量方法进行了初步摸索。 相似文献
812.
XiaoRongZHOU PeiFangLIU LinZHUANG JunTaoLU 《中国化学快报》2004,15(7):823-826
Mass spectrometer is connected through an adaptor to a sealed small battery to probe the gas phase changes inside the battery. The factors influencing the response time are analyzed with a simplified model. The feasibility of the new technique is demonstrated with a Ni-Cd battery, showing different profiles of MS intensities for O2 and H2. Compared with gas chromatography, this technique has the advantage of being noninvasive and should be useful for the study and diagnostic examination of small sealed batteries. 相似文献
813.
Xiaowei Pei Weimin Liu Jingcheng Hao 《Journal of polymer science. Part A, Polymer chemistry》2008,46(9):3014-3023
Polymer‐grafted multiwalled carbon nanotube (MWCNT) hybrid composite which possess a hard backbone of MWCNT and a soft shell of brush‐like polystyrene (PSt) were synthesized. The reversible addition fragmentation chain transfer (RAFT) agents were successfully immobilized onto the surface of MWCNT first, and PSt chains were subsequently grafted from sidewall of MWCNT via RAFT polymerization. Chemical structure of resulting product and the quantities of grafted polymer were determined by Fourier transform infrared, thermal gravimetric analysis, nuclear magnetic resonance, and X‐ray photoelectron spectra. Transmission electron microscopy and field emission scanning electron microscopy images clearly indicate that the nanotubes were coated with a polymer layer. Furthermore, the functionalized MWCNT as additives was added to base lubricant and the tribological property of resultant MWCNT lubricant was investigated with four‐ball machines. The results indicate that the functionalization led to an improvement in the dispersion of MWCNT and as additives it amended the tribological property of base lubricant. The mechanism of the significant improvements on the tribological properties of the functionalized MWCNT as additives was discussed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3014–3023, 2008 相似文献
814.
In the presence of sodium iodate and pyridine, several 5,6-dihydroxylated benzo[b]furan derivatives were synthesized via oxidation-Michael addition of β-dicarbonyl compounds with catechols in a one-pot procedure. The final products were confirmed by ESMS, NMR, and single-crystal X-ray diffraction study. The mechanism different from that of electrochemical methods was proposed based on DFT calculation. 相似文献
815.
A smart optical liquid level sensor based on the theory of connected vessels is introduced. The Hg cladding optical waveguide (HCOW) is taken as its probe, and the change of liquid level is presented by the change of the HCOW length. Both the theoretical analysis and experiments show that when the waveguide diameter and the light wavelength are certain, the optical power loss decreased linearly with the increase of the HCOW length. By detecting the power loss of HCOW, optimizing the structure of probe and selecting the appropriate apparatus for detection, the real time detection of liquid level with high precision can be got. The experimental results show that the measurement accuracy is 5.2 mm within 10 m liquid level, and its theoretical precision can be up to 0.02%. 相似文献
816.
M~n是一个紧致无边单连通的n(≥3)维Riemannian流形,S~n为R~(n+1)中的单位球面.本文所关注的流形满足截面曲率K_M≤1,而Ricci曲率Ric(M)≥(n+2)/4以及体积V(M)≤3/2(1+η)V(S~(2n)),这里η是一个仅和维数n有关的常数.最终将给出一个具有正的Ricci曲率的球定理新证明. 相似文献
817.
818.
用激光溅射 -分子束技术研究了Cu等离子体与乙腈团簇的气相反应 .观察到Cu+ (CH3 CN) n、CH2 CN+ (CH3 CN) n、H+ (CH3 CN) n 和CH3 CHCN+ (CH3 CN) n 四个种类的团簇离子 .考察了等离子体作用于脉冲分子束的不同位置 ,对团簇产物的种类和尺寸大小的影响 .实验结果表明 ,Cu+ (CH3 CN) n 是由Cu+ 与乙腈团簇直接缔合而成 ,CH2 CN+ (CH3 CN) n、H+ (CH3 CN) n 主要是激光等离子体中的电子与乙腈团簇碰撞电离产生的 ,而CH3 CHCN+ (CH3 CN) n 是由乙腈团簇离子内的离子 分子反应生成的 . 相似文献
819.
Xue-Feng Pei Nigel H. Greig Judith L. Flippen-Anderson Sheng Bi Arnold Brossi 《Helvetica chimica acta》1994,77(5):1412-1422
Oxindole 11 , obtained on 3-[2′-(dimethylamino)ethyl]alkylation of oxindole 12 , yielded, on stereoselective reduction with sodium dihydridobis(2-methoxyethoxy)aluminate, aminoalcohol 8 (Scheme 2). The quaternary methiodide 10 , obtained from 8 with MeI, gave, in nucleophilic displacements concurring with a Hofmann elimination, (±)-esermethole 6 , (±)-5-O-methylphysovenol ( 14 ), (±)-5-O-methyl-1-thiaphysovenol ( 15 ), and (±)-1-benzyl-1-demethylesermethole ( 16 ). Syntheses of (±)-1-benzyl-1-demethylphenserine ( 18 ), (±)-1-demethylphenserine ( 19 ), and (±)-phenserine ( 4 ) from 6 and 16 are described. Optically active 8a and 8b , obtained by chemical resolution, similarly gave the enantiomers 6a and 14a–16a of the (3aS)-series (prepared earlier from physostigmine ( 1a )) and their (3R)-enantiomers. The anticholinesterase activity of (±)- 4 , (±)- 18 , and (±)- 19 was compared with that of their optically active enantiomers. 相似文献
820.
PeiZhiGUO DeJunSUN JieZHANG 《中国化学快报》2003,14(9):973-976
The chemical composition, morphology of the particles of positively charged layered double hydroxides (LDHs) were studied by ICP, Mastersizer, TEM. The preliminary results indicated that with adding LDHs to 1% laponite dispersion the yield stress of laponite/LDHs mixed dispersions increased at first, then decreased dramatically to a minimum, and the yield stress rose again when LDHs increased further. 相似文献