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941.
论述了核磁中心采用的相对集中管理模式.集中管理模式主要体现在上样辅助、中央供气、数据集中上传与下载3个方面.另外,还提出了未来可以从集中供高纯N2和LN22个方面进一步改善中心的集中管理模式,从而能够更好的优化测试效率和工作环境. 相似文献
942.
943.
PBL教学是以问题为基础的教学模式,将PBL教学模式应用到分析化学课堂教学中,有助于提高学生发现问题、分析问题和在实践中解决问题的能力。对发展PBL模式用于药学专业的分析化学课堂教学进行了探讨,提出了可以在教学及考核阶段从教学内容和课堂教学方式上应用PBL模式,结合多媒体、网络、CAI等现代化的教学手段,促进分析化学课堂教学的改革,培养具备创新能力的药学专业大学生。 相似文献
944.
从高分子化学课程的特点和教学现状出发,针对应用化学的专业特点和培养目标,从课堂内和课堂外2个层面入手,注重理论和实践的有机结合,进行高分子化学课程多维互动教学模式的探索。通过多维互动教学模式的开展不断激发学生学习的激情,培养学习兴趣;结合教学内容提供学生更多自主探索和思考的空间,提高学生主观能动性;从学生的需求和专业发展的角度,逐步提高学生专业素养和专业能力,切实提高课程的教学效果。 相似文献
945.
946.
In the last years, the development of new methods for analyzing accurate and precise individual metalloproteins is of increasing importance, since numerous metalloproteins are excellent biomarkers of oxidative stress and diseases. In that way, methods based on the use of post column isotopic dilution analysis (IDA) or enriched protein standards are required to obtain a sufficient degree of accuracy, precision and high limits of detection. This paper reports the identification and absolute quantification of Cu,Zn-superoxide dismutase (Cu,Zn-SOD) in cytosol and mitochondria from mice hepatic cells using a innovative column switching analytical approach. The method consisted of orthogonal chromatographic systems coupled to inductively coupling plasma-mass spectrometry equipped with a octopole reaction systems (ICP-ORS-MS) and UV detectors: size exclusion fractionation (SEC) of the cytosolic and mitochondrial extracts followed by online anion exchange chromatographic (AEC) separation of Cu/Zn containing species. After purification, Cu,Zn-SOD was identified after tryptic digestion by molecular mass spectrometry (MS). The MS/MS spectrum of a doubly charged peptide was used to obtain the sequence of the protein using the MASCOT searching engine. This optimized methodology reduces the time of analysis and avoids the use of sample preconcentration and clean-up procedures, such as cut-off centrifuged filters, solid phase extraction (SPE), precipitation procedures, off-line fractions insolates, etc. In this sense, the method is robust, reliable and fast with typical chromatographic run time less than 20 min. Precision in terms of relative standard deviation (n = 5) is of 3–5% and detection limits is 0.21 ng Cu g−1. 相似文献
947.
Histidine‐modified organic‐silica hybrid monolithic column for mixed‐mode per aqueous and ion‐exchange capillary electrochromatography 下载免费PDF全文
Sheng Tang Shujuan Liu Xiaojing Liang Xiaofen Tang Xingcai Wu Yong Guo Xia Liu Shengxiang Jiang 《Journal of separation science》2015,38(12):2046-2052
A novel organic‐silica hybrid monolith was prepared through the binding of histidine onto the surface of monolithic matrix for mixed‐mode per aqueous and ion‐exchange capillary electrochromatography. The imidazolium and amino groups on the surface of the monolithic stationary phase were used to generate an anodic electro‐osmotic flow as well as to provide electrostatic interaction sites for the charged compounds at low pH. Typical per aqueous chromatographic behavior was observed in water‐rich mobile phases. Various polar and hydrophilic analytes were selected to evaluate the characteristics and chromatographic performance of the obtained monolith. Under per aqueous conditions, the mixed‐mode mechanism of hydrophobic and ion‐exchange interactions was observed and the resultant monolithic column proved to be very versatile for the efficient separations of these polar and hydrophilic compounds (including amides, nucleosides and nucleotide bases, benzoic acid derivatives, and amino acids) in highly aqueous mobile phases. The successful applications suggested that the histidine‐modified organic‐silica hybrid monolithic column could offer a wide range of retention behaviors and flexible selectivities toward polar and hydrophilic compounds. 相似文献
948.
Separation of cannabinoids on three different mixed‐mode columns containing carbon/nanodiamond/amine‐polymer superficially porous particles 下载免费PDF全文
Chuan‐Hsi Hung Janusz Zukowski David S. Jensen Andrew J. Miles Clayton Sulak Andrew E. Dadson Matthew R. Linford 《Journal of separation science》2015,38(17):2968-2974
Three mixed‐mode high‐performance liquid chromatography columns packed with superficially porous carbon/nanodiamond/amine‐polymer particles were used to separate mixtures of cannabinoids. Columns evaluated included: (i) reversed phase (C18), weak anion exchange, 4.6 × 33 mm, 3.6 μm, and 4.6 × 100 mm, 3.6 μm, (ii) reversed phase, strong anion exchange (quaternary amine), 4.6×33 mm, 3.6 μm, and (iii) hydrophilic interaction liquid chromatography, 4.6 × 150 mm, 3.6 μm. Different selectivities were achieved under various mobile phase and stationary phase conditions. Efficiencies and peak capacities were as high as 54 000 N/m and 56, respectively. The reversed phase mixed‐mode column (C18) retained tetrahydrocannabinolic acid strongly under acidic conditions and weakly under basic conditions. Tetrahydrocannabinolic acid was retained strongly on the reversed phase, strong anion exchange mixed‐mode column under basic polar organic mobile phase conditions. The hydrophilic interaction liquid chromatography column retained polar cannabinoids better than the (more) neutral ones under basic conditions. A longer reversed phase (C18) mixed‐mode column (4.6 × 100 mm) showed better resolution for analytes (and a contaminant) than a shorter column. Fast separations were achieved in less than 5 min and sometimes 2 min. A real world sample (bubble hash extract) was also analyzed by gradient elution. 相似文献
949.
采用课题研究模式,指导学生完成一定课题任务,使学生学会独立思考、分析问题和解决问题,最终培养创新能力。该模式实施步骤包括选题、学生遴选、调研、实验、结项等主要步骤。课题类型包括实验型、工程(设计)型和创业型。详细分析了每一步的具体要求和实施方法,并结合近年来课题组指导学生的实例,探讨了该模式的特点和实施效果。结果表明,该模式对培养学生的创新能力是有效的、可行的,但需进一步改进完善。 相似文献
950.
Yang Jin Hongbin Zhang Yimei Yin Katsuyoshi Nishinari 《Colloid and polymer science》2006,284(12):1371-1377
Tapping mode atomic force microscopy was used to study the bacterial polysaccharide curdlan deposited from dimethyl sulfoxide (Me2SO) and NaOH aqueous solutions. For curdlan in Me2SO, flexible single chains corresponding to a disordered conformation were observed at a concentration of 5 mg/l, and the chain diameter was measured to be 0.65±0.05 nm, which showed good agreement with the expected value of the single polysaccharide chain. Because the concentration of curdlan increased, the chains became more rigid and aggregated, subsequently, the network structures of curdlan appeared. However, curdlan samples deposited from a 5 mM NaOH solution showed entirely different conformations. The chains observed were almost in the form of micelles of several nanometers, which were supermolecular assemblies. The heterogeneously dense zones were observed as the curdlan concentration increased to 40 mg/l. When the concentration of curdlan was above 100 mg/l, which might cause the real concentration of curdlan on the mica substrate after drying treatment exceeding some critical value of gelation, gel network structures were formed. Keeping on increasing the concentration of curdlan, the image showed a more homogeneous fibrous network. 相似文献