用正交设计制作酶过程曲线的方法

用正交设计制作酶过程曲线的方法郭慧云，张立，李彬，刘兰英（吉林大学分子生物学系，长春１３００２３）正交设计￣［１］，是用正交表安排多因素试验、用统计数学原理进行数据分析的一种科学方法。为培养学生的实际工作能力，应让本科生在专门化实验课中得到使用该方法...     

烟用水基胶中2,2,4-三甲基-1,3-戊二醇二异丁酸酯增塑剂含量的测定

通过正己烷振荡提取烟用水基胶中的2，2，4-三甲基-1，3-戊二醇二异丁酸酯（TXIB），采用气相色谱-质谱/选择离子监测法分析烟用水基胶中的TXIB，内标法定量.结果表明：方法的线性相关系数为0.999 7，检出限为0.75 μg/mL，RSD为1.78%，回收率在95.3%~103.1%之间，说明方法的线性良好、检出限低、重复性好、准确性高，适于烟用水基胶中TXIB的测定.     

原子吸收光谱法测定电解铜中微量锡和锑

建立了用偏振塞曼原子吸收光谱法测定电解铜中微量元素锡、锑含量的方法。本方法用硝酸溶解样品，所得试样用空气-乙炔火焰原子吸收光谱法测定，工作曲线法定量。测定结果满意。     

离子色谱法测定电厂用高纯水中的Na+

建立了离子色谱法准确测定电厂用高纯水中Na^ 的方法，对于两种不同的进样方式进行了试验，测定结果的相对标准偏差分别为3．3％、1．4％，回收率分别为92．0％～105．0％、95．0％～101．0％，该方法满足监测要求，是电厂用高纯水中Na^ 测定的理想方法。     

直流电沉积Ni-Al2O3纳米阵列体系结构与性能

用直流电沉积的方法成功地将Ni金属填入了用二次腐蚀方法制备的氧化铝模板纳米级孔洞中，分别用电子显微镜、X射线衍射仪和振动样品磁强计对Ni阵列体系进行结构观察和磁性表征.结果表明，用二次腐蚀方法制得的多孔氧化铝模板的孔洞排布的有序性很高.被组装的Ni呈单晶结构并具有一定的择优取向； Ni-Al2O3阵列体系有明显的垂直磁各向异性，适用于垂直磁记录介质.     

氢化物发生－ICP发射光谱法测定饮用水中痕量砷

本文提出用简易氢化物发生系统与ＩＣＰ光谱仪联用，测定自来水和矿泉水中痕量砷的简易、快速的方法。用氢氧化铁共沉淀水中痕量砷，沉淀用离心机分离和富集。选择最优化的反应条件和工作条件。方法的检测限为０．００２μｇ／Ｌ，精密度为２％，回收率在９０％～１０４％之间。     

一种使荧光法与其它方法测得水中油含量有可比性的方法

使荧光法与其它方法测得水中油含量有可比性的方法，涉及工业废水的环境监测技术．具体是：对取样分组用荧光图谱测定的方法扫描图谱，同时采用通常的其它检测方法测量；对不同浓度的样品从低向高逐个测定，确定荧光值对含油浓度关系曲线；对照含油浓度曲线，在相同的条件下用荧光法直接测定无溶剂萃取水样的含油量。本发明使得用荧光法经萃取或不经萃取直接测得的水中石油类含量与重量法、红外法、紫外法、GC—MS等的测定结果之间具有可比性，从而使测定更经济、环保、高效、灵敏的荧光法在更大范围内得到推广应用，解决了在线监测水中石油类含量的关键性技术障碍。     

壳聚糖膜的量子化学计算

采用Gaussian92程序，用AM1半经验量子化学方法优化壳聚糖膜模型的分子结构，在此基础上用量子化学从头算STO-3G方法计算，研究了壳聚糖-戊二醛的阳离子膜和阴离子膜的几何构型、能量、键序和电子迁移，讨论了膜形成的成键形式和膜的结构及稳定性     

微波消解-ICP-AES法测定氧化铝中杂质元素

采用微波消解法，将样品用磷酸溶解，用ICP-AES测定氧化铝中Na、K、Ca、Si、Fe、Ti、Mn、Zn、Cu、V、Cr和B等12种杂质元素，采用测定标样、加标回收试验和精密度试验证明该方法简便快速，准确可靠。     

α,β—二甲基脱水丙酮联苯酰的合成

用两种改进的方法，由联苯甲酰与３－戊酮反应制得α、β－二甲基脱水丙酮联苯酰（１），其结构由熔点、ＩＲ、ＨＮＭＲ确定，从ＨＮＭＲ谱推测：用乙醇作溶剂，加入ＫＯＨ、联苯甲酰及３－戊酮，于室温搅拌３ｈ后放置３天，所得ＩＡ为两对对映体；用苯作溶剂，加入适量聚乙二醇４００（ＰＥＧ４００），其它反应物同方法１，加热回流３ｈ，所得产物ＩＡ仅为一对对映体，改进的方法都缩短短了反应时间，上述两种方法得到的产物，经脱     

Friedel-Crafts Polymers. 6. Friedel-Crafts Polycondensation of p-Xylylerte Dibromide with Salicylic Acid and β-Resorcyiic Acid

Polymers were prepared by condensing p-xylylene dibromide separately with salicylic acid and β-resorcylic acid in the presence of anhydrous ferric chloride in dioxane. The polymer samples_were characterized by elemental analysis, by IR spectral study, by M determined by vapor pressure osmometry, by nonaqueous conducto-metric titration in pyridine, by TGA in air, and by viscosity measurements of polymer solutions in DMF. Polymeric metal chelates of Cu²⁺, Co²⁺, Zn²⁺, Ni²⁺, and Fe³⁺ with polymer samples were prepared and characterized by elemental analysis, by IR spectral study, and by TGA in air. The chelation ion-exchange properties of the polymer samples were studied by employing the batch equilibration method.     

Akt is involved in the inhibition of cell proliferation by EGF

Axin is a negative regulator of the Wnt/beta-catenin pathway and is involved in the regulation of axis formation and proliferation. Involvement of Axin in the regulation of other signaling pathways is poorly understood. In this study, we investigated the involvement of Akt in growth regulation by Axin in L929 fibroblasts stimulated by EGF. Akt activity was increased by EGF treatment and Ras activation, respectively. Both the EGF- and Ras-induced Akt activations were abolished by Axin induction, as revealed by both Western blot and immunocytochemical analyses. The proliferation and Akt activation induced by EGF were decreased by Axin induction, and the effects of EGF were abolished by treatment of an Akt-specific inhibitor. Therefore, Axin inhibits EGF-induced proliferation of L929 fibroblasts by blocking Akt activation.     

Substoichiometric determination of phosphorus

Phosphorus in orchard leaves (NBS SRM-1571) and spinach (SRM-1570) was determined by various substoichiometric analytical methods such as the direct method, GRASHCHENKO's method and the method of carrier amount variation. All samples were labelled with³²P radioisotope. The data obtained by the method of carrier amount variation were also treated by the method of least squares instead of De VOE's method. Phosphorus concentration in orchard leaves was 0.206±0.011% by the direct method, 0.219±0.011% by GRASHCHENKO's method, 0.211±0.011% by the method of carrier amount variation and 0.207±0.007% by the method of least squares, respectively. These values agree with the value reported by NBS (0.21±0.01%). Furthermore, these concentrations obtained by various substoichiometric methods were compared with those by radioactivation reported in a prevoius paper.     

湿化学法制备硅纳米线阵列及其光电化学产氢性能分析

为了探究不同方法条件下制备的硅纳米线阵列电极产氢性能异同,文中分别采用了两步金属辅助催化无电刻蚀法、一步金属辅助催化无电刻蚀法以及阳极氧化法来制备硅纳米线阵列用作为光电分解水电池光阴极材料.通过FESEM、XRD和UV-Vis-IRDRS等手段对实验样品的形貌、晶型、减反性表征,发现相比于其他2种方法所得硅纳米线样品,两步金属辅助催化无电刻蚀法制备的硅纳米线结构晶型保持更好,表面缺陷更少.光电化学测试表明两步金属辅助催化无电刻蚀法制备的硅纳米线光电化学性能表现最优,其光电流密度值是一步法的4倍,阳极氧化法的40倍;转移电荷电阻仅是一步法制备的硅纳米线阵列阻值的1/3,阳极氧化法制备的1/1000.     

Role of binding entropy in the refinement of protein-ligand docking predictions: analysis based on the use of 11 scoring functions

We present results of testing the ability of eleven popular scoring functions to predict native docked positions using a recently developed method (Ruvinsky and Kozintsev, J Comput Chem 2005, 26, 1089) for estimation the entropy contributions of relative motions to protein-ligand binding affinity. The method is based on the integration of the configurational integral over clusters obtained from multiple docked positions. We use a test set of 100 PDB protein-ligand complexes and ensembles of 101 docked positions generated by (Wang et al. J Med Chem 2003, 46, 2287) for each ligand in the test set. To test the suggested method we compared the averaged root-mean square deviations (RMSD) of the top-scored ligand docked positions, accounting and not accounting for entropy contributions, relative to the experimentally determined positions. We demonstrate that the method increases docking accuracy by 10-21% when used in conjunction with the AutoDock scoring function, by 2-25% with G-Score, by 7-41% with D-Score, by 0-8% with LigScore, by 1-6% with PLP, by 0-12% with LUDI, by 2-8% with F-Score, by 7-29% with ChemScore, by 0-9% with X-Score, by 2-19% with PMF, and by 1-7% with DrugScore. We also compared the performance of the suggested method with the method based on ranking by cluster occupancy only. We analyze how the choice of a clustering-RMSD and a low bound of dense clusters impacts on docking accuracy of the scoring methods. We derive optimal intervals of the clustering-RMSD for 11 scoring functions.     

Luminescent,optical, magnetic and metamaterial behavior of cerium complexes

The complexes of cerium with nitrogen, oxygen and sulfur donor ligands were prepared by conventional method. These newly synthesized complexes were characterized by FTIR, UV–Vis, DART Mass, TGA, PXRD, SEM and TEM techniques. The magnetic studies were carried out by the vibrating sample magnetometer. The optical constants were measured by absorption and reflection spectra as a function of wavelength. The concentration dependence of refractive index and absorption was observed by the experimental method, which reveals that these parameters are affected by change in concentration. The optical band gap obtained from Tauc-plot indicates its probability to be a good semiconductor. The luminescence behavior of these cerium complexes was observed by the absorption and emission spectra and the emission life time was calculated by their life time spectra.     

Photosensitization by phenylalanine of carboxylic acids, amides, and peptides in frozen aqueous solution

Abstract— In order to elucidate the mechanism of the photosensitization of proteins and peptides by aromatic amino acids, the behaviour of aliphatic carboxylic acids and amides upon irradiation in frozen aqueous solution in the presence of phenylalanine (l-Phe) has been studied by EPR spectroscopy. EPR signals are much stronger when acids or amides are irradiated in the presence of l-Phe, showing that they are photosensitized by the aromatic amino acid. The species observed are either alkyl radicals, or radicals formed by abstraction of a hydrogen atom from a molecule of acid or arnide. A mechanism is proposed which involves the capture by carboxyl or amide carbonyl groups of hydrated electrons released by the photo-excited l-Phe, followed by the splitting of the resulting anion free radical with the formation of alkyl radicals, and transfer reactions leading to more stable free radicals. In peptides, which are also photosensitized by l-Phe, electrons are captured preferably by the carboxylic carbonyl groups.     

Determination of Mg, Ti and Cl in Ziegler-Natta catalysts by WDXRF

A method for determination of Mg, Ti and Cl in Ziegler-Natta (ZN) catalysts by wavelength dispersive X-ray fluorescence (WDXRF) spectrometry was developed. For comparative reasons, Ti was determined by spectrophotometry, Mg by complexometry and Cl by argentometric titration. Direct pressing was shown to be unsuitable for sample preparation due to catalyst decomposition. For Ti and Mg measurements, catalyst samples were calcinated at 1000 °C and pressed at 275 MPa. Their determination by the fundamental parameters based on the Ti Ka line measurement was shown to be equivalent to those results obtained by univariate calibration or by the classical methods. Cl was determined by aqueous extraction, followed by deposition on a support. Chloride loss was observed. Fixation of Cl as AgCl on polytetrafluoroethylene (FHLC) millipore membrane afforded the best results. Nevertheless, measurements by WDXRF were shown to be inferior to those obtained by argentometric titration.     

Determination of certain trace impurities in uranium concentrates by activation analysis

A method is presented for the simultaneous determination of chromium, iron, cobalt and zinc in samples of uranium concentrates, oxides and metallic uranium by neutron-activation analysis. The method involves adequate decontamination of gross fission product activities by adsorption on silica gel, removal of uranium by solvent extraction, separation of most carrier-free rare-earth activities by coprecipitation with aluminium chloride, and, finally, fractional separation of the elements concerned by ion-exchange chromatography. The method can assay ppm of such elements in limited quantities of samples by scintillation gamma-ray spectrometric analysis with a reproducibility of 10-15%.