实验室废液的回收及效果评价——以“铬废液回收及评价”为例

This paper introduces an experiment about waste liquid recovery and effect evaluation in laboratory. Through this experiment, the basic operations of crystal preparation, chemical analysis and instrumental analysis are further consolidated. At the same time, it allows students to experience a series of possible problems of condition selection and control in the process of waste liquid treatment. We hope to improve the students' ability to analyze and solve problems, enhance their interest in learning, and strengthen their humanistic education.     

A Study of the Silylation of 1,8-Dihydroxynaphthalene

Twelve compounds each having a six membered Si-contained heterocycle, have been successfully synthesized. Of these eleven compounds have never been reported in the literature. The structures were confirmed by Spectral analysis and elementary analysis. The stability and properties of these compounds is also discussed.     

Study of localized molecular orbitals using group theory methods and its approach to the many-electron correlation problem. IV. The symmetry-adaptation of many-center integrals and hamiltonian matrix elements in MCSCF calculations

Group theoretic methods are presented for the transformations of integrals and the evaluation of matrix elements encountered in multiconfigurational self-consistent field (MCSCF) and configuration interaction (CI) calculations. The method has the advantages of needing only to deal with a symmetry unique set of atomic orbitals (AO) integrals and transformation from unique atomic integrals to unique molecular integrals rather than with all of them. Hamiltonian matrix element is expressed by a linear combination of product terms of many-center unique integrals and geometric factors. The group symmetry localized orbitals as atomic and molecular orbitals are a key feature of this algorithm. The method provides an alternative to traditional method that requires a table of coupling coefficients for products of the irreducible representations of the molecular point group. Geometric factors effectively eliminate these coupling coefficients. The saving of time and space in integral computations and transformations is analyzed. © 1994 by John Wiley & Sons, Inc.     

丙烯腈中微量有机杂质的测定

本文采用ＸＥ－６０交联弹性石英性细管柱及４０７有机体埴充柱气色谱法可分分析丙烯腈中有机杂质。通过对柱长、担体粒度、液膜厚度、柱温和载气流量的选择。确定出最佳色 谱条件。     

A combined diffraction and dielectric properties investigation of Ba3MnNb2O9 complex perovskites

A combined synthesis, diffraction and dielectric properties investigation of the dependence (and effect) of Mn²⁺/Nb⁵⁺ ordering in Ba₃MnNb₂O₉ (BMN) upon annealing atmosphere and processing conditions has been carried out. Annealing in different atmospheres was not found to significantly alter either nominal stoichiometry or structure type. The obtained structure type (disordered metrically cubic or ordered trigonal) as well as the measured electrical properties (in particular, the dielectric loss) were, however, found to be sensitive to the synthesis route. Samples obtained via solid-state reaction were found to be predominantly of 1:2 Mn²⁺/Nb⁵⁺ ordered, trigonal structure type whereas samples obtained via an aqueous solution route were found to be of a Mn²⁺/Nb⁵⁺ ‘disordered’, metrically cubic structure type. All solid-state synthesized samples showed reasonable dielectric properties. The microwave dielectric constant and dielectric quality factor, Q, at 8 GHz of an as-synthesized BMN sample were 38 and 100, respectively. By contrast, the dielectric loss of the metrically cubic, Mn²⁺/Nb⁵⁺ ‘disordered’ samples obtained via an aqueous solution synthesis process were significantly worse.     

Structural basis for inhibition of protein tyrosine phosphatases by Keggin compounds phosphomolybdate and phosphotungstate

Protein-tyrosine phosphatases (PTPs) constitute a family of receptor-like, and cytoplasmic enzymes, which catalyze the dephosphorylation of phosphotyrosine residues in a variety of receptors and signaling molecules. Together with protein tyrosine kinases (PTKs), PTPs are critically involved in regulating many cellular signaling processes. In this study, diverse compounds were screened for PTP inhibition and selectively screened for inhibitors with the end product inhibition properties. Among phosphate analogues and their derivatives for PTP inhibition, Keggin compounds phosphomolybdate (PM) and phosphotungstate (PT) strongly inhibited both PTP-1B and SHP-1, with K(i) values of 0.06-1.2 micromM in the presence of EDTA. Unlike the vanadium compounds, inhibition potencies of PM and PT were not significantly affected by EDTA. PM and PT were potent, competitive inhibitors for PTPs, but relatively poor inhibitors of Ser/Thr phosphatase. Interestingly, PM and PT did not inhibit alkaline phosphatase at all. The crystal structure of PTP-1B in complex with PM, at 2.0 A resolution, reveals that MoO(3), derived from PM by hydrolysis, binds at the active site. The molybdenium atom of the inhibitor is coordinated with six ligands: three oxo-ligands, two apical water molecules and a S atom of the catalytic cysteine residue. In support of the crystallographic finding, we observed that molybdenium oxides (MoO(3), MoO(2), and MoO(2)Cl(2)) inhibited PTP-1B with IC(50) in the range 5-15 micromM.     

稀土锰氧化物La0.7Ca0.3Mn1-xCuxO3低场磁电阻及电传输特性研究

采用溶胶-凝胶法制备了系列多晶CMR材料La0.7Ca0.3Mn1-xCuxO3（x=0%,1%,5%,10%,15%,20%）。在77-350 K温度范围内测量了样品的电阻率及磁电阻大小。实验结果发现：系列样品TC随掺杂量增加而递减;系列样品的电阻率峰及磁电阻峰在整个测温范围内随掺杂量的增加均依次被展宽直至消失,当掺杂量为x≥10%时,电阻率随温度的变化在整个测温范围内呈现绝缘相行为;同时还发现,掺杂量为x≥10%时,样品的磁电阻在整个测温区内基本表现为隧穿磁电阻。基于我们采用蒙特卡罗模拟方法提出的逾渗模型及隧穿磁电阻模型,对样品的磁电阻行为进行了很好的解释。对系列样品的ρ-T曲线进行lnρ-T^-（1/4）系拟合,发现掺杂量为x=10%样品在整个温区内的lnρ-T^-（1/4）系基本呈线性。     

镓(Ⅲ)-茜素氨羧络合剂在碳糊电极上的阳极吸附伏安法研究及应用

研究了镓(Ⅲ)-茜素氨羧络合剂(ALC)在碳糊电极上的阳极吸附伏安行为,并以此建立了一种高灵敏度、高选择性测定镓的吸附伏安法.在0.12 mol/L HAc-NaAc-0.24 mol/L邻苯二甲酸氢钾底液(pH 4.5)中,-0.10 V (vs.SCE) 富集90 s (或180 s),以250 mV/s扫速线性扫描至0.90 V, Ga3+-ALC在碳糊电极上产生灵敏的与ALC的峰电位相差近230 mV的吸附氧化峰,其二次导数峰电流与镓浓度在5.0×10-10～8.0×10-7 mol/L范围内呈线性关系;富集240 s检出限达3.0×10-10 mol/L(S/N=3).探讨了电极反应机理.该法用于粮食样品中镓的测定,结果满意.     

Analysis of oxosteroids by nano-electrospray mass spectrometry of their oximes

A method for the analysis of neutral oxosteroids by electrospray mass spectrometry is described. The oxosteroids are converted into their oximes by treatment with hydroxyammonium chloride in aqueous methanol. Intense peaks corresponding to protonated oxime molecules are observed in nano-electrospray mass spectra. The detection limits for the oximes of progesterone, pregnenolone and dehydroepiandrosterone were 2.5, 5 and 25 pg/microL, respectively, approximately 20 times lower than for the underivatised steroids. The signal intensities were proportional to the concentration of the steroids in the range of 500 to 2.5 pg/microL. Fragmentation by collision-induced dissociation (CID) was studied using oximes of 28 model steroids carrying an oxo group at C-3, C-17 or C-20. Some of the steroid oximes were labelled with deuterium or (15)N. Fragment ions were observed which yielded useful structural information. Upon CID, protonated oximes of 3-oxo-Delta(4)-steroids produced abundant ions by cleavage through the B-ring and by loss of the side chain, while protonated oximes of saturated 3-oxosteroids did not give abundant ions by cleavage through the B-ring. Protonated oximes of 20-oxosteroids unsubstituted at C-21, C-17 or C-16 produced a characteristic ion at m/z 86 containing the side chain, C-16 and C-17. Protonated oximes of steroids containing only a 17-oxo group gave fewer ions of diagnostic value. Coupled with the selective isolation of steroid oximes from a biological matrix this method of derivatisation and CID may be used for the analysis of neutral oxosteroids in biological samples.     

2-Deoxy-d-glucose Promotes Buforin IIb-Induced Cytotoxicity in Prostate Cancer DU145 Cells and Xenograft Tumors

Inhibition of the glycolytic pathway is a critical strategy in anticancer therapy because of the role of aerobic glycolysis in cancer cells. The glycolytic inhibitor 2-Deoxy-d-glucose (2-DG) has shown potential in combination with other anticancer agents. Buforin IIb is an effective antimicrobial peptide (AMP) with broad-spectrum anticancer activity and selectivity. The efficacy of combination treatment with 2-DG and buforin IIb in prostate cancer remains unknown. Here, we tested the efficacy of buforin IIb as a mitochondria-targeting AMP in the androgen-independent human prostate cancer cell line DU145. Combining 2-DG with buforin IIb had a synergistic toxic effect on DU145 cells and mouse xenograft tumors. Combination treatment with 2-DG and buforin IIb caused stronger proliferation inhibition, greater G1 cell cycle arrest, and higher apoptosis than either treatment alone. Combination treatment dramatically decreased L-lactate production and intracellular ATP levels, indicating severe inhibition of glycolysis and ATP production. Flow cytometry and confocal laser scanning microscopy results indicate that 2-DG may increase buforin IIb uptake by DU145 cells, thereby increasing the mitochondria-targeting capacity of buforin IIb. This may partly explain the effect of combination treatment on enhancing buforin IIb-induced apoptosis. Consistently, 2-DG increased mitochondrial dysfunction and upregulated Bax/Bcl-2, promoting cytochrome c release to initiate procaspase 3 cleavage induced by buforin IIb. These results suggest that 2-DG sensitizes prostate cancer DU145 cells to buforin IIb. Moreover, combination treatment caused minimal hemolysis and cytotoxicity to normal WPMY-1 cells. Collectively, the current study demonstrates that dual targeting of glycolysis and mitochondria by 2-DG and buforin IIb may be an effective anticancer strategy for the treatment of some advanced prostate cancer.