Determination of the Interaction of Arsenic and Human Serum Albumin by Online Microdialysis Coupled to LC with Hydride Generation Atomic Fluorescence Spectroscopy

Study on the stoichiometry and affinity of the arsenicals bound to HSA is an important step toward a better understanding of arsenic toxic effects. After incubation of As^III or As^V with HSA at the physiological conditions (pH 7.43 and 37 °C), the free arsenicals and arsenic-HSA complexes were separated and detected by the combined techniques of microdialysis and liquid chromatography with hydride generation atomic fluorescence spectroscopy (MD–LC–HGAFS). The decrease of As^III peak response rather than As^V indicated that HSA reacted with As^III but not As^V. The binding plots indicated that the binding between HSA and As^III was in Scatchard pattern when the concentration ratios of As^III to HSA were ≤1:1. The strong binding sites (n ₁) were 1.6 and the stability constant (K ₁) was 1.54 × 10⁶ M⁻¹. When the concentration ratios of As^III to HSA were >1:1, the binding was in Plasvento pattern with the stability constant K ₂ ≅ 0 and no specific binding of As^III with HSA. On the contrary, As^V did not show binding with HSA. The results showed that As^III reacted with HSA more readily than As^V, which provides a chemical basis for arsenic toxicity.

     

Existence and uniqueness of solutions for a non-uniformly parabolic equation

In this paper, we study a generalized Burgers equation u_t+(u²)_x=tu_xx, which is a non-uniformly parabolic equation for t>0. We show the existence and uniqueness of classical solutions to the initial-value problem of the generalized Burgers equation with rough initial data belonging to .     

Efficient syntheses of benzothiazepines as antagonists for the mitochondrial sodium-calcium exchanger: potential therapeutics for type II diabetes

Type II diabetes mellitus is a chronic metabolic disorder that can lead to serious cardiovascular, renal, neurologic, and retinal complications. While several drugs are currently prescribed to treat type II diabetes, their efficacy is limited by mechanism-related side effects (weight gain, hypoglycemia, gastrointestinal distress), inadequate efficacy for use as monotherapy, and the development of tolerance to the agents. Consequently, combination therapies are frequently employed to effectively regulate blood glucose levels. We have focused on the mitochondrial sodium-calcium exchanger (mNCE) as a novel target for diabetes drug discovery. We have proposed that inhibition of the mNCE can be used to regulate calcium flux across the mitochondrial membrane, thereby enhancing mitochondrial oxidative metabolism, which in turn enhances glucose-stimulated insulin secretion (GSIS) in the pancreatic beta-cell. In this paper, we report the facile synthesis of benzothiazepines and derivatives by S-alkylation using 2-aminobenzhydrols. The syntheses of other bicyclic analogues based on benzothiazepine, benzothiazecine, benzodiazecine, and benzodiazepine templates are also described. These compounds have been evaluated for their inhibition of mNCE activity, and the results from the structure-activity relationship (SAR) studies are discussed.     

酞侧基聚芳醚砜／对苯二甲酸乙二酯－对羟基苯甲酸嵌段共聚物共混物的研究

酞侧基聚芳醚砜／对苯二甲酸乙二酯－对羟基苯甲酸嵌段共聚物共混物的研究李刚，殷敬华，李滨耀（中国科学院长春应用化学研究所，长春，１３００２２）关键词酞侧基聚芳醚砜，热致性液晶高聚物，原位复合材料，对苯二甲酸乙二酯－对羟基苯甲酸嵌段共聚物将热塑性树脂与热...     

硝酸双-(1，10-二氮杂菲)苯乙酸锌(Ⅱ)配合物的合成和晶体结构

合成了标题化合物晶体。经X射线单晶结构分析确定该化合物晶体的化学结构式为［Zn(phen)₂PAC］NO₃·2HPAC(phen=1,10-二氮杂菲，HPAC=苯乙酸)。结构中Zn(Ⅱ)与一个苯乙酸和二个1，10-二氮杂菲形成不规则八面体配合物，苯乙酸为双齿配位。     

Hydrothermal synthesis and luminescent properties of Sb-doped Sr3(PO4)2

Sb³⁺-doped Sr₃(PO₄)₂ crystals has been synthesized using phosphoric acid, strontium hydroxide and antimony powder as the raw materials through a hydrothermal reaction method. The crystallinity and the microstructure were investigated using X-ray diffraction and scanning electron microscopy. The photoluminescent property was investigated using luminescent spectrometer. Phase pure Sr₃(PO₄)₂ crystal was obtained and it has a shape of hexagonal rod. It showed the emission and excitation peaks at 396, 250, and 215 nm, respectively, indicating that the emission is attributed to ³P₁-¹S₀ transition and the excitation is attributed to ¹S₀-³P₁ and ¹S₀-¹P₁ transition. It was also observed that the intensity of photoluminescence is thermally stable up to 673 K.     

Diorganotin(IV) derivatives of arylhydroxamic acids: synthesis, properties and antitumor activity

Series of diorganotin(IV) complexes of 4-X-benzohydroxamic acid [X = NH₂ (HL₁), NO₂ (HL₂) or F (HL₃)] formulated as [R₂SnL₂] and [R₂Sn(L)]₂O (R = Me, Et, nBu or Ph) have been prepared and characterized by FT-IR, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopies, elemental analyses, FAB⁺-MS and melting point determination. They are stable in air, soluble in alcohols and in hydroalcoholic solution and, in some cases, in water. Their in vitro antitumor activity against a series of human tumor cell lines was tested and, in a few of them, is identical to, or even higher than, that of cisplatin. For the mononuclear dialkyltin compounds, the activity generally increases with the length of the carbon chain of the alkyl ligand, being higher for the complexes with benzohydroxamato ligands bearing an electron-acceptor substituent (X = NO₂ or F). No structure-activity relationship based on the Hammett’s σ_p constant, or related ones, has been recognized.     

两性物质溶液pH计算

提出了两性物质可按酸碱组分之间是否发生反应进行分类,并分别给出了这二类两性物质溶液pH计算的近似式。     

克尔效应对高斯光束聚焦特性的影响

利用菲涅尔—基尔霍夫衍射积分公式,研究薄片近似情况下的Kerr效应带来的波前畸变对高斯光束聚焦特性的影响.在相位延迟为－2~2 rad的范围内进行的模拟计算表明：正Kerr效应能提高高斯光束的聚焦强度、增大相对焦移量、提高聚焦光束的焦平面桶中功率和降低几何焦平面的峰值光强;而负Kerr效应,则会降低聚焦强度、增大相对焦移量、降低聚焦光束的焦平面桶中功率和几何焦平面的峰值光强.可以通过增大光束菲涅尔数来抑制Kerr效应对聚焦特性的影响.