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61.
62.
Yaming Niu Xiaoliang Zhu Lingzhi Liu Yan Zhao Zhenhua Jiang 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(9):1459-1467
The new monomer (4‐(4′‐trifluoromethyl)phenoxyphenyl)hydroquinone (TFPOPH) was synthesized in a three‐step synthesis. A series of poly(aryl ether ketone) copolymers were prepared by the reaction of (4‐(4′‐Trifluoromethyl)phenoxyphenyl)hydroquinone and hydroquinone (HQ) with 4,4′‐difluorobenzophenone (DFB) in the presence of potassium carbonate in tretramethylene sulfone (TMS). Thermal analyses of the fluorinated copolymers showed that the glass transition temperature and 5.0% weight loss temperature are similar with that of PEEK, and the crystallinity decreased with increasing of TFPOPH. For the copolymer synthesized with the molar fraction of TFPOPH in the diphenol monomers (TFPOPH, HQ) being over 0.2, no cold crystallization temperature and melting temperature were detected, indicating that these copolymers are almost amorphous. The crystal structure of the copolymers with the molar fraction of TFPOPH being not higher than 0.2 is rhombic. The solubility in polar aprotic solvents of poly(aryl ether ketone)s copolymers increases and dielectric constant decreases step by step. 相似文献
63.
Langang Niu Ramaswamy Nagarajan Dingsong Feng Lynne A. Samuelson 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1983-1990
Main‐chain thermotropic liquid‐crystalline polyesters containing rigid biphenyl mesogens and flexible spacers were synthesized by chemo‐enzymatic route. The enzyme‐catalyzed polymerization showed high regio‐ and chemo‐ selectivity, and is environmentally friendly. The resulting polyesters were characterized with 1H‐NMR, 13C‐NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and polarized light optical microscopy (POM). 相似文献
64.
Na Guo Dawei Yang Keyume Ablajan Xiaohong Niu Bin Fan Zhiguo Wang Jingang Dai Xiaoxia Wu Baidong Liu 《Journal of separation science》2013,36(12):1953-1958
A rapid analytical method based on rapid resolution LC coupled with MS/MS was first established to quantify seven alkaloids in processed Fuzi decoction. The chromatographic method was optimized to allow simultaneous analysis of all analytes in 5 min and demonstrated good linearity (r > 0.9995), repeatability (RSD < 4.36%), intra‐ and interday precisions (RSD < 5.07%) with good accuracies (97.76–105.08%) and good recovery (95.0–107.5%) of seven alkaloids, namely higenamine, benzoylhypaconine, benzoylmesaconine, benzoylaconine, aconitine, hypaconitine, and mesaconitine. The LODs for these markers were in the range of 2.30–17.00 pg/mL. Quantitative analysis of the seven alkaloids in Baifupian decoction and Heishunpian decoction showed that the content of the seven marker chemicals varied significantly and concluded that the quality of Fuzi was greatly affected by different processed methods. The developed method could be used as a rapid, sensitive, and reliable approach for assessment of the quality of processed Fuzi and related decoction. 相似文献
65.
Xiaofeng Niu Weifeng Li Hongbo Xu Xia Liu Lin Qi 《Journal of separation science》2013,36(13):2090-2095
Isoquinoline alkaloids are the primary active ingredients of Corydalis, but an analytical method for quality assessment of the active ingredients in Corydalis impatiens (Pall). Fisch has not been reported. A new, simple, and multiple‐component quantification method was developed for the simultaneous quantification of 11 isoquinoline alkaloids including capnoidine, chelianthifoline, bicuculline, protopine, isoapocavidine, apocavidine, cavidine, tetrahydroepiberberine, ochotensimine, tetrahydrocoptisine, and tetrahydrocorysamine in C. impatiens. Separation of the isoquinoline alkaloids was performed on a RP C18 column (150 × 4.6 mm, 5 μm) with potassium dihydrogen phosphate buffer (pH 2.5, adjusted by phosphoric acid)/acetonitrile (53:47, v/v) containing 0.3% sodium dodecyl sulfonate. The flow rate and detection wavelength were set at 1 mL/min and 295 nm, respectively. Full validation of the assay was carried out including linearity, precision, accuracy, stability, LOD, and limit of quantitation. All calibration curves showed a good linear relationship (r > 0.999) in test range. The results demonstrated that the developed method was reliable, rapid, and specific. Six batches of C. impatiens samples from different sources were determined using the established method. The contents of alkaloids ranged from 11.68 to 351.83 μg/g. This method can be applied for quality evaluation and control of C. impatiens. Eleven isoquinoline alkaloids were first reported on simultaneous determination with HPLC. 相似文献
66.
Cui Yang Chunyan Ren Xiangfan Piao Narayanan Kannan Donghao Li 《Journal of separation science》2013,36(21-22):3599-3607
A continuous‐flow, on‐line sample pretreatment technique using a silica gel microsyringe extractor has been developed. All steps including extraction, separation, clean‐up, and concentration occur in the microsyringe. The overall sample pretreatment process takes <10 min per sample. Different polarity chemicals in the plant sample are successively extracted and separated, and analyzed in parallel using HPLC–UV and HPLC–UV–MS/MS. Polycyclic aromatic hydrocarbons, alkylphenols, and plant hormones were determined as model compounds for nonpolar, intermediate polarity, and polar fractions, respectively. All the parameters that influence the extraction and separation efficiency of the microsyringe extractor have been optimized and evaluated. Under the optimized conditions, recoveries of target compounds ranged from 78.4 to 101.9%, the RSD was <12.8% and the square of the correlation coefficient was >0.99. Complex plant samples of Sambucus Mandshurica Kitag have been tested using this method. Fluorene, phenanthrene, pyrene, and plant hormones were detected in all the samples, and concentrations ranged from 24.2–34.9, 43.8–67.1, 25.9–29.2, and 14.5~110.8 ng/g, respectively. 相似文献
67.
Mengbo Zhou Li Song Feng Niu Kangying Shu Wenxiang Chai 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(5):463-466
In the title CuII complex, [Cu(C19H14O3P)2(C3H7NO)(H2O)2], the molecule is bisected by a twofold axis relating the two 2‐(diphenylphosphoryl)benzoate (ODPPB) ligands. The asymmetric unit consists of a CuII metal centre on the symmetry axis, an ODPPB ligand, one water ligand and one dimethylformamide (DMF) ligand (disordered around the twofold axis). The CuII ion has fivefold coordination provided by two carboxylate O atoms from two ODPPB ligands, two O atoms from two coordinated water molecules and another O atom from a (disordered) DMF molecule, giving a CuO5 square‐pyramidal coordination geometry. The ODPPB ligand adopts a terminal monocoordinated mode with two free O atoms forming two strong intramolecular hydrogen bonds with the coordinated water molecules, which may play a key role in the stability of the molecular structure, as shown by the higher release temperature for the coordinated water molecules than for the coordinated DMF molecule. The optical absorption properties of powder samples of the title compound have also been studied. 相似文献
68.
An interesting dimmer (excimer)-induced-AIE characteristic of 2-phenylisothiazolo[5,4-b]pyridin-3(2H)-one was observed. By using a ring-opening reaction, we developed a novel fluorescent probe based on sub-micron particles of 2-phenylisothiazolo[5,4-b]pyridin-3(2H)-one in water. 相似文献
69.
Mao Chen Ting Zhao Zhong‐Xin Zhu Chao Niu Dan‐dan Ruan Mao‐Wei Ni Xuan Zhou Li‐Tai Jin 《Electrophoresis》2013,34(24):3277-3286
An improved Stains‐All (ISA) staining method for phosphoproteins in SDS‐PAGE was described. Down to 0.5–1 ng phosphoproteins (α‐casein, β‐casein, or phosvitin) can be successfully selectively detected by ISA stain, which is approximately 120‐fold higher than that of original Stains‐All stain, but is similar to that of commonly used Pro‐Q Diamond stain. Furthermore, unlike the original Stains‐All protocol that was time consuming and light unstable, ISA stain could be completed within 60 min without resorting to protect the gels from light during the whole staining procedure. According to the results, it is concluded that ISA stain is a rapid, sensitive, specific, and economic staining method for a broad application to the research of phosphoproteins. 相似文献
70.
Ming Hu Yansu Guo Huifang Chen Weisong Duan Chunyan Li 《Applied biochemistry and biotechnology》2013,170(2):301-319
Alternative splicing is a common strategy for creating functional diversities of proteins. While conventional identification of splice variants generally targets individual genes in amyotrophic lateral sclerosis, we present a novel exon-centric array that allows genome-wide identification of splice variants and concurrently provides analysis of gene expression. Compare 1 was asymptomatic SOD1G93A transgenic mice with nontransgenic littermates; compare 2 was symptomatic with asymptomatic transgenic mice. RT-PCR was performed to validate. Pathway and GO analysis were performed on abnormal genes. These findings could guide us to demonstrated the potential influence of mutant human CuZn-SOD1 and of splicing regulation in pathological processes. 相似文献