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991.
Yang X Sun X Lv Z Guo W Du Y Wang E 《Chemical communications (Cambridge, England)》2010,46(46):8818-8820
A new kind of silver micro-dendrites with no surfactants protected has been synthesized for the separation and detection of DNA merely by earth gravity as the density of silver is larger than that of water. Through this approach, the DNA of human T-lymphotropic virus type I (HTLV-I) can be detected down to 10 pM with the detection range from 10 pM to 100 nM. 相似文献
992.
Quasi-classical trajectory (QCT) calculations are employed for the reaction F + HO(0,0)→HF + O based on the adiabatic potential energy surface (PES) of the ground 3A″triplet state. The average rotational alignment factor P2(j′·k) as a function of collision energy and the four polarization dependent generalized differential cross sections have been calculated in the center-of-mass (CM) frame, separately. The distribution P(θr) of the angle between k and j′, the distribution P(θr) of dihedral angle denoting k-k′-j′ correlation, and the angular distribution P(θr, Φr) of product rotational vectors in the form of polar plots are calculated as well. The effect of Heavy-Light-Heavy (HLH) mass combination and atom F's relatively strong absorbability to charges on the alignment and the orientation of product molecule HF rotational angular momentum vectors j′ is revealed. 相似文献
993.
Microchip-based systems have been developed rapidly due to their desirable advantages over conventional platforms. Higher level system integration and complex microdevices are emerging to satisfy the demand for high-throughput and large-scale applications. However, most of the devices need to be fabricated with complicated microvalves and micropumps, which, to some extent, limit the use of the novel technique. In this study, a simple microdevice was developed to perform chemotherapy resistance analysis in lung cancer cell line SPCA1. This device includes a PDMS chip for which a simple external small clip served as a microvalve to control the fluid flow so that the parallel control experiment could be carried out simultaneously, and a syringe pump, which supplied the cells with fresh medium mimicking the microenvironment in vivo. Cell culture, detection of drug resistance related protein P-glycoprotein (P-gp) and glutathione S-transferase-π (GST-π) and cell viability after VP-16 treatment on experimental (pretreated with corresponding inhibitors) and control groups were achieved. The results demonstrated that the cells could grow and spread well for at least 3 days. The expression of P-gp and GST-π was obviously downregulated by corresponding inhibitors. The percentage of apoptotic cells for P-gp inhibition group increased 2.9-fold compared with that of control group (23.7 ± 2.6 versus 8.1 ± 3.0%, p<0.05), while for GST-π inhibition, there was no obvious distinction between the experimental and control group. The simple microdevice is capable of integrating parallel operations involving cell culture and functional analysis, offering an easy and flexible platform for a stable long-term cell culture and comparison research. 相似文献
994.
Two kinds of online preconcentration techniques including large-volume sample stacking-sweeping and selective-exhaustive injection-sweeping (SEI-S) were employed in CE to develop a rapid, simple and sensitive method for determination of melamine (MM) and its derivatives such as ammeline (AMN), ammelide (AMD) and cyanuric acid (CA) in liquid milk products. Though the sensitivity of large-volume sample stacking-sweeping is not particularly high, it can be used to detect all the four compounds simultaneously. However, it is very difficult to improve the sensitivity of these four compounds by using single SEI-S method directly, owing to their completely different extents of protonation or deprotonation. Grouping can solve this problem perfectly. After the four compounds are divided into two groups (MM/AMN and AMD/CA), cation-SEI-S or anion-SEI-S can be applied for their online stacking. In cation-SEI-S, the detection limits for MM and AMN were both 0.01 ng/mL based on the signal-to-noise ratio of 3. In anion-SEI-S, the detection limits were 0.05 and 0.02 ng/mL for CA and AMD, respectively. Results of this study show a great potential for the SEI-S method to be a useful tool for the rapid and sensitive determination of MM and its derivatives in liquid milk products. 相似文献
995.
Sicen Wang Meng Sun Yanmin Zhang Hui DuLangchong He 《Journal of chromatography. A》2010,1217(32):5246-5252
The intracellular kinase domains of epidermal growth factor receptor (EGFR) in some tumor cells such as human epidermal squamous cells (A431 cells) are an important target for drug discovery. We have developed a new A431/cell membrane chromatography (A431/CMC)-online–high performance liquid chromatography/mass spectrometry (HPLC/MS) method for screening EGFR antagonists from medicinal herbs such as traditional Chinese medicines (TCMs). In this study, A431 cells with high EGFR expression levels were used to prepare cell membrane stationary phase (CMSP) in an A431/CMC model. The retention fractions eluted from the CMSP column were enriched onto an ODS pre-column and then switched into an HPLC/MS system by combining a 10 port columns switching valve. The screening results found that oxymatrine and matrine from Radix sophorae flavescentis (RSF) were the targeted components which could act on EGFR in similar manner of gefitinib as a control drug. There was a good relationship of their inhibiting effects on EGFR secretion and A431 cell growth in vitro. This new A431/CMC-online-HPLC/MS method can be applied for screening EGFR antagonists from TCMs such as RSF. It will be a useful method for drug discovery with natural medicinal herbs as a leading compound resource. 相似文献
996.
Ji XY Zhong ZJ Xue ST Meng S He WY Gao RM Li YH Li ZR 《Chemical & pharmaceutical bulletin》2010,58(11):1436-1441
A series of novel glutarimide compounds were synthesized and their antiviral activities were evaluated. The compounds displaying the strongest antiviral activities included 5, 6f, 7e and 9 against coxsackievirus B3 (Cox B3), 10 and 6f against influenza virus A (influenza A) and 7a against herpes simplex virus 2 (HSV-2). However, most of the synthetic glutarimides showed comparatively much weaker activity against influenza A, Cox B3 and HSV-2 than the natural glutarimide compounds tested. Based on the results, it seemed likely that a conjugated system at the β-substituted moiety provides stronger antiviral activity. 相似文献
997.
Xuan Liu Lingxiao Cheng Dr. Jianping Lei Hui Liu Prof. Huangxian Ju 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(35):10764-10770
Bidentate chelation, meso‐2,3‐dimercaptosuccinic acid (DMSA), was used as a stabilizer for the synthesis of CdTe quantum dots (QDs). The bidentate chelate QDs, characterized with FT‐IR, PL, and UV/Vis spectroscopy; element analysis; and high‐resolution transmission electron microscope, exhibited surface traps due to the large surface/volume ratio of QD particle and the steric hindrance of the DMSA molecule. The unpassivated surface of the QDs produced a narrower band gap than the core and electrochemiluminescent (ECL) emission at relatively low cathodic potential. In air‐saturated pH 7.0 buffer, the QDs immobilized on electrode surface showed an intense ECL emission peak at ?0.85 V (vs. Ag/AgCl). H2O2 produced from electrochemical reduction of dissolved oxygen was demonstrated to be the co‐reactant, which avoided the need of strong oxidant as the co‐reactant and produced a sensitive analytical method for peroxidase‐related analytes. Using hydroquinone/horseradish peroxidase/H2O2 as a model system, a new, reagentless, phenolic, ECL biosensor for hydroquinone was constructed, based on the quenching effect of ECL emission of QDs by consumption of co‐reactant H2O2. The biosensor showed a linear range of 0.2–10 μM with acceptable stability and reproducibility. This work opens new avenues in the search for new ECL emitters with excellent analytical performance and makes QDs a more attractive alternative in biosensing. 相似文献
998.
以天然产物齐墩果酸为母体,设计合成齐墩果酸衍生物,采用计算机辅助药物设计,对C-3、C-28位结构改造,设计合成12个未见文献报道的靶向VEGFR受体抑制剂; 采用噻唑蓝(MTT)法,用人肝癌细胞(HepG2)和乳腺癌细胞(MCF-7)对其进行初步体外抗肿瘤活性筛选;其结构经1H-NMR、13C-NMR谱确证。活性测试得出化合物I7、II1与阳性对照药相比有较强抑制作用,其抗肿瘤活性高于母体OA,分子对接结果显示I7和II1 与 VEGFR 受体具有较好的结合能力,值得进一步研究。 相似文献
999.
1000.
Hong-Yan Zhu Xiang-Ying Meng Yong-Li Bao Chun-Lei Yu Yin Wu Yu-Xin Li 《Chromatographia》2010,71(7-8):617-622
A novel, simple and specific normal-phase liquid chromatography (NPLC) method has been developed for simultaneous determination of the four lathyrane diterpenoids, lathyrol-5,15-diacetate-3-benzoate (1, L3), lathyrol-5,15-diacetate-3,7-dibenzoate (2, L2), Δ6,17-epoxide-5,15-diacetate-3-phenylacetate (3, L1), lathyrol-5,15-diacetate-3-nicotinate (4, L8) in the hexane extract of the seeds of Euphorbia lathyris and “ZI-JIN-DING” pastille. The method showed good linearity for the four analytes (r 2 > 0.99), the intra-day and inter-day variations (RSD) were less than 3%, and the recoveries ranged from 99.4 to 100.6%. This method was successfully used to determine the four lathyrane diterpenoids in the seeds of Euphorbia lathyris and “ZI-JIN-DING” pastille, and could be applied for their quality control. 相似文献