Study of adsorption behavior of bilirubin on human-albumin monolayer using a quartz crystal microbalance

The quartz crystal microbalance was employed to study the adsorption behavior of bilirubin on human-albumin layer, which was chemically bound to the self-assembled monolayer of 4-aminothiophenol on the surface of a gold electrode of the crystal via glutaraldehyde. A long-time adsorption process of bilirubin that took place on a human-albumin-modified surface was observed, and the adsorption kinetic parameters were estimated from the in situ frequency measurements. The amount of adsorbed bilirubin increased with increasing of both hydrogen ions and bilirubin concentration and was larger than that estimated based on the conclusion that there are two affinity sites for bilirubin per albumin molecule. With the present method, the displacement of bilirubin from an albumin layer caused by aspirin was also examined. QCM measurement provides a facile method for in situ monitoring of the adsorption/desorption of bilirubin on proteins layers.     

Selective excitation in spin systems with homogeneous broadening

We have found that the application of a weak radio frequency (rf) pulse to a spin system with indirect spin-spin (J) couplings can produce a narrow inverted peak in spectral regions where there are many overlapping peaks. Examples of three compounds with (1)H-(1)H J couplings and one with (1)H-(13)C J couplings are given. The dependences of the signals on the frequency, duration, and amplitude of the weak rf irradiation have been studied. For an rf power of gammaB(1)/2pi=1.0 Hz, pulse widths longer than 0.25 s consistently produce inverted narrow peaks in spectral regions with unresolved peaks. An interpretation of the origin of this unusual result of selective excitation in spin systems with homogeneous broadening is given: the inverted signal observed can be considered as a cumulative effect of the weak rf irradiation acting on many uncorrelated transitions that are slightly off resonance on both sides of the irradiating frequency; the only role of the J couplings (or dipolar couplings in liquid crystals) is to produce a large number of closely spaced peaks that overlap with each other. Computer simulations of both coupled and noninteracting spin systems have been carried out, and the results support this interpretation.     

有或没有Alq3参与情况下LiF和Al的化学反应

利用X光电子能谱（XPS）和高分辨电子能量损失谱（HREELS）研究了几种条件下LiF和Al的化学反应.在有Alq3参与的情况下,LiF和Al在室温下发生反应.在Al/LiF/Alq3系统中,Li 1s的峰发生了0.25 eV的位移,同时F 1s也发生了相应的位移.在没有Alq3参与的情况下,加热样品至350 K后,在Li 1s峰的低能端0.85 eV处出现了一个伴峰.XPS研究表明,这个伴峰对应的是金属态的Li 1s.HREELS的结果也验证了这一结论.     

对模拟细胞色素P-450的卟啉类化合物的研究

本文评述和总结了细胞色素P-450模型体系研究现状。     

葡萄酒分析中模式识别方法的研究：Ⅱ.原汁含量的多元判别分析

本实验采用常规分析方法，分析了１８个不同含汁量酒样的乙醇，总酸，挥发酸，固定酸，干浸出物，ｐＨ值，灰份，灰份碱度，总酚，甘油，钾，钠，镁，干浸出物与甘油比，Ｑ值，修正干浸出物共１７个变量。采用计算机模式识别技术，利用逐步判别方法，得出了葡萄酒中原汁含量种逐步别方法的判别函数和回判结果。     

Low field chemical shifts in 13carbon NMR spectra of 1,3-dehydroadamantane compounds possessing “inverted carbon atoms”

1,3-Dehydroadamantanes, which possess “inverted carbon atoms” in a cyclopropyl moiety, display low field ¹³C-NMR chemical shifts for carbon atoms situated across from the cyclopropyl group. This long range effect also shows in 2,4-dehydroadamantane and is therefore not due to the presence of especially strained inverted carbons.     

Determination of order parameters from carbon–fluorine dipolar coupling

Abstract

A convenient NMR method for the determination of the order parameters for liquid crystals containing a fluorinated phenyl ring is described. The technique consists of measuring the carbon-fluorine dipolar coupling constants in the one-dimensional C-13 spectrum of the molecule. The order parameters may then be calculated for the fluorine-containing ring with a high degree of precision because of the excellent resolution afforded by the 1-D C-13 spectra. The method is used to determine the core order parameters for 4-n-hexyloxybenzilidene-4′-fluoroaniline (FAB-OC6). The results of the carbon-fluorine dipolar coupling method are compared with two established methods for determining the core order parameters of phenyl rings, namely deuterium NMR spectroscopy and SLF/VAS, a two-dimensional C-13 NMR spectroscopy. Some comments about the orientational properties of the fluorinated liquid crystal FAB-OC6 are made.     

Randomized two‐way cross‐over bioequivalence study of two amoxicillin formulations and inter‐ethnicity pharmacokinetic variation in healthy Malay volunteers

The objectives of this study were to develop a new deproteinization method to extract amoxicillin from human plasma and evaluate the inter‐ethnic variation of amoxicillin pharmacokinetics in healthy Malay volunteers. A single‐dose, randomized, fasting, two‐period, two‐treatment, two‐sequence crossover, open‐label bioequivalence study was conducted in 18 healthy Malay adult male volunteers, with one week washout period. The drug concentration in the sample was analyzed using high‐performance liquid chromatography (UV–vis HPLC). The mean (standard deviation) pharmacokinetic parameter results of Moxilen® were: peak concentration (C_max), 6.72 (1.56) µg/mL; area under the concentration–time graph (AUC_0–8), 17.79 (4.29) µg/mL h; AUC_0–∞, 18.84 (4.62) µg/mL h. Those of YSP Amoxicillin® capsule were: C_max, 6.69 (1.44) µg/mL; AUC_0–8, 18.69 (3.78) µg/mL h; AUC0_0–∞, 19.95 (3.81) µg/mL h. The 90% confidence intervals for the logarithmic transformed C_max, AUC_0–8 and AUC_0–∞ of Moxilen® vs YSP Amoxicillin® capsule was between 0.80 and 1.25. Both C_max and AUC met the predetermined criteria for assuming bioequivalence. Both formulations were well tolerated. The results showed significant inter‐ethnicity variation in pharmacokinetics of amoxicillin. The C_max and AUC of amoxicillin in Malay population were slightly lower compared with other populations. Copyright © 2014 John Wiley & Sons, Ltd.