Synthesis,characterization, and drug release behaviors of a novel thermo‐sensitive poly(N‐acryloylglycinates)

In this study, a novel thermo‐sensitive poly(N‐acryloylglycinates) was prepared in order to get a potential drug release carrier. The corresponding monomers and the polymers were characterized with Fourier‐transform infrared (FTIR) and ¹H NMR. The thermo‐sensitivity of the poly(N‐acryloylglycinates) was evaluated by measuring their lower critical solution temperatures (LCST) in water, inorganic salt solution, and different pH solutions. The results indicated that poly(N‐acryloylglycine methyl ester) (NAGME) and poly(N‐acryloylglycine ethyl ester) (NAGEE) exhibit a reversible thermo‐sensibility in their aqueous solutions at 61.5 and 12.5°C, respectively. However, no thermo‐sensitive behavior of poly(N‐acryloylglycine propyl ester) (NAGPE) was found due to its over hydrophobicity. The swelling studies on hydrogels were carried out at different temperatures, in different pH, and inorganic salt solutions. The hydrogels showed a remarkable phase transition at about 35°C with changing temperature. The release rate of caffeine from the thermo‐sensitive hydrogel was apparently decreased as the crosslinker content increased and temperature decreased. Seventy five percent caffeine from the polymeric hydrogel with 5% NMBA (N, N‐methylenebis(acrylamide)) was released at room temperature within 240 min, whereas 95.4% caffeine diffused into the medium at 37°C. Copyright © 2009 John Wiley & Sons, Ltd.     

Ionic liquid-modified silica as a new stationary phase for chromatographic separation

A new stationary phase based on silica modified with 1-methyl-3-propylimidazolium chloride was synthesized and characterized in this paper. A derivative of 1-methyl-3-propylimidazolium chloride was used to chemically modify the surface of silica particles to act as the stationary phase for HPLC. The modified particles were characterized by Fourier Transform Infrared (FT-IR), ¹³C NMR spectroscopy and thermogravimetric analysis (TGA). The surface modification procedure rendered particles with a surface coverage of 0.89 μmol/m² of alkylimidazolium chloride. Columns packed with the modified silica and blank silica particles were tested under HPLC conditions. Preliminary evaluation of the stationary phase for HPLC was performed using aromatic compounds as model compounds. The separation mechanism appears to involve multiple interactions including ion exchange, hydrophobic and electrostatic interactions.     

Total synthesis and absolute configuration determination of (+)-subincanadine F

The first asymmetric synthesis of indole alkaloid (+)-subincanadine F was successfully accomplished with the uncommon 7-endo-trig stereoselective radical cyclization as the key step and its absolute configuration was thus assigned.     

A new biomarker of protein oxidation degree and site using angiotensin as the target by MS

Hydroxyl radicals generated from Fenton reaction were used to damage the angiotensin. The oxidative damage degree and sites of peptides were measured by HPLC–MS and MS/MS. Experimental results proved that the oxidative damage degree increased with longer reaction time. The results also showed that the side chains of phenylalanine and tyrosine in angiotension can be attacked by hydroxyl radicals to form the oxidative products. A new strategy was established to monitor the oxidative degree and sites of peptides and laid the foundation for protein oxidation. This method can be used to investigate the mechanism of protein oxidative damage caused by oxidative stress which is induced by environmental pollutants and physiological activities. There will also be a wide application in the research of pathogenesis of some disease related to oxidative stress.     

Degradation of furan tebufenozide in laboratory and field trials

Furan tebufenozide is a newly developed insect growth regulator and has been applied as a pesticide in agriculture in China. Its degradation under both laboratory and field conditions was investigated, and the degradation kinetics was fitted by simple first order kinetics (SFO) model and first order double exponential (FOD) model. Laboratory studies were conducted with or without light in five simulated media (sterilized deionized water, river water, soil solution, sterilized soil and natural soil). No dissipations of furan tebufenozide were observed in sterilized aqueous and soil media under light prevented conditions, whereas degradation occurred under all the other conditions in the laboratory. Derived from SFO and FOD models, DT₅₀ in the dark and light laboratory conditions was in the range of 39.7–82.5 and 1.1–8.0 days, respectively. These results indicated that microbes and light were the main factors for the degradation of the pesticide in the laboratory. During field trials, derived from the SFO model, DT₅₀ and DT₉₀ were 30.3 and 100.5 days, while derived from the FOD model, DT₅₀ and DT₉₀ were 28.9 and 274.9 days, respectively. Compared with laboratory experiments, field trials were influenced by multiple factors. Therefore, the SFO model could not fit experimental data as well as the FOD model did in field trials.     

基于傅里叶变换红外光声光谱的包膜控释肥料聚合物膜疏水性的表征

以不饱和有机硅改性的丙烯酸酯为基材,在不同条件下制备了30种水基聚合物包膜控释肥料模型膜,测定了模型膜的溶胀度及模型膜的傅里叶变换红外光声光谱.分别以红外光声光谱和溶胀度为自变量和因变量进行简单相关分析,同时也构建了偏最小二乘模型,并利用该模型对模型膜的疏水性进行预测.结果表明,聚合物模型膜具有明显不同的疏水性,其红外光声光谱具有相似的吸收特征,但不同吸收带的相对强度发生明显改变;常用的简单相关分析无法实现模型膜疏水性的预测,表明模型膜的疏水性与谱区更多的特征峰相关;基于偏最小二乘法的多元校正分析具有很好的预测能力,模型的校正系数(R2)为0.9864,校正标准误差为0.70%,验证标准误差为1.92%.此模型可用于模型膜疏水性的预测.本方法样品用量少,测定快速,操作简便且可实现原位测定,为控释肥料包膜材料的研制提供新的手段.     

Construction of two fluorescence‐labeled non‐combined DNA index system miniSTR multiplex systems to analyze degraded DNA samples in the Chinese Han Population

MiniSTR loci have been demonstrated to be an effective approach in recovering genetic information from degraded specimens, because of the reduced PCR amplicon sizes which improved the PCR efficiency. Eight non‐combined DNA index system miniSTR loci suitable for the Chinese Han Population were analyzed in 300 unrelated Chinese Han individuals using two novel five fluorescence‐labeled miniSTR multiplex systems(multiplex I: D10S1248, D2S441, D1S1677 and D9S2157; multiplex II: D9S1122, D10S1435, D12ATA63, D2S1776 and Amelogenin). The allele frequency distribution and forensic parameters in the Chinese Han Population were reported in this article. The Exact Test demonstrated that all loci surveyed here were found to be no deviation from Hardy–Weinberg equilibrium. The accumulated power of discrimination and power of exclusion for the eight loci were 0.999999992 and 0.98, respectively. The highly degraded DNA from artificially degraded samples and the degraded forensic case work samples was assessed with the two miniSTR multiplex systems, and the results showed that the systems were quite effective.     

Formation and characterization of a hydrophilic polymer hydrogel under gamma irradiation

Formation and characterization of hydrogel of a hydrophilic polymer in a wide range of gamma absorbed doses is reported. An aqueous solution contains 2% polyvinyl alcohol (PVA) by mass irradiated under gamma rays of ⁶⁰Co was chosen for study. The hydrogel was synthesized without using any additives. It was found that gel fraction is an exponential saturation function that increases with an increase of absorbed dose while swelling ratio is an exponential saturation function that decreases with an increase of absorbed dose. The results are described by energy transfer model.     

Synthesis, structure and mesomorphism of new cholesteric monomers and smectic comblike polymers

Seven new cholesteric monomers (M-1−M-7) and the corresponding smectic comblike polymers containing cholesteryl groups (P-1−P-7) were synthesized. The chemical structures and purity were characterized by FT-IR, ¹H NMR, and elemental analyses. The specific optical rotations were evaluated with a polarimeter. The mesomorphism was investigated by polarizing optical microscopy, differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction. The specific optical rotation values of these monomers and polymers with the same numbers of phenyl ring and terminal groups were nearly equal, however, they decreased with increasing the aryl numbers in the mesogenic core. M-1−M-7 showed oily streak texture and focal conic texture, or fingerprint texture, or spiral texture of cholesteric phase. P-1−P-7 showed the smectic A phase. The melting, clearing, and glass transition temperatures increased, and the mesophase temperature ranges widened with increasing the aryl number in the mesogenic core. Surprisingly, although the molecular structures of M-6 and M-7 were similar to those of M-4, namely the mesogenic cores contained three phenyl rings, their phase behavior had a considerable difference, and T_m and T_i of M-6 and M-7 were less than those of M-4. In addition, M-6 and M-7 also showed an obvious glass transition. TGA showed that all the polymers had good thermal stabilities.