Synthesis,biological evaluation and SAR studies of benzimidazole derivatives as H1-antihistamine agents

A series of benzimidazole derivatives have been designed,synthesized and evaluated for H₁ antihistamine activity.Six compounds have showed potent antihistamine H₁ activity.The primary SAR analysis indicated that benzyl or benzylidinyl substituted on the exo-nitrogen atom and C2 of the benzimidazole were significant.Further experiments indicated that compound 17d displayed excellent activity to reduce mast cell degranulation,moderate anti-PAF activity and decreased potency on hERG compared to astermizole.Hence compound 17d could serve as anti-allergic agent for further development.     

Functional improvement of porcine neonatal pancreatic cell clusters via conformal encapsulation using an air-driven encapsulator

Transplantation of islet cells into diabetic patients is a promising therapy, provided that the islet cells are able to evade host immune rejection. With improved islet viability, this strategy may effectively reverse diabetes. We applied 2% calcium alginate to generate small and large capsules to encapsulate porcine neonatal pancreatic cell clusters (NPCCs) using an air-driven encapsulator. After encapsulation, the viability was assessed at 1, 4, 7, 14 and 28 days and secretion of functional insulin in response to glucose stimulation were tested at days 14 and 28. Selective permeability of the small alginate capsules was confirmed using various sizes of isothiocyanate-labeled dextran (FITC-dextran). Encapsulation of NPCCs was performed without islet protrusion in the small and large capsules. The viability of NPCCs in all experimental groups was greater than 90% at day 1 and then gradually decreased after day 7. The NPCCs encapsulated in large capsules showed significantly lower viability (79.50 ± 2.88%) than that of naïve NPCCs and NPCCs in small capsule (86.83 ± 2.32%, 87.67 ± 2.07%, respectively) at day 7. The viability of naïve NPCCs decreased rapidly at day 14 (75.67 ± 1.75%), whereas the NPCCs encapsulated in small capsules maintained (82.0 ± 2.19%). After 14 and 28 days NPCCs' function in small capsules (2.67 ± 0.09 and 2.13 ± 0.09) was conserved better compared to that of naïve NPCCs (2.04 ± 0.25 and 1.53 ± 0.32, respectively) and NPCCs in large capsules (2.04 ± 0.34 and 1.13 ± 0.10, respectively), as assessed by a stimulation index. The small capsules also demonstrated selective permeability. With this encapsulation technique, small capsules improved the viability and insulin secretion of NPCCs without islet protrusion.     

Molecular dynamics study on the relationships of modeling, structural and energy properties with sensitivity for RDX-based PBXs

In this paper,a primary model is established for MD(molecular dynamics) simulation for the PBXs(polymer-bonded explosives) with RDX(cyclotrimethylene trinitramine) as base explosive and PS as polymer binder.A series of results from the MD simulation are compared between two PBX models,which are represented by PBX1 and PBX2,respectively,including one PS molecular chain having 46 repeating units and two PS molecular chains with each having 23 repeating units.It has been found that their structural,interaction energy and mechanical properties are basically consistent between the two models.A systematic MD study for the PBX2 is performed under NPT conditions at five different temperatures,i.e.,195 K,245 K,295 K,345 K,and 395 K.We have found that with the temperature increase,the maximum bond length(L max) of RDX N N trigger bond increases,and the interaction energy(E N-N) between two N atoms of the N-N trigger bond and the cohesive energy density(CED) decrease.These phenomena agree with the experimental fact that the PBX becomes more sensitive as the temperature increases.Therefore,we propose to use the maximum bond length L max of the trigger bond of the easily decomposed and exploded component and the interaction energy E N-N of the two relevant atoms as theoretical criteria to judge or predict the relative degree of heat and impact sensitivity for the energetic composites such as PBXs and solid propellants.     

无机钛硅原料体系合成TS-1催化丙烯环氧化反应

研究了无机钛硅原料体系合成的ＴＳ－１催化丙烯环氧化的反应,并与经典法、修正法制得样品的催化性能进行了比较。考察了搅拌、Ｎａ２ＣＯ３加入量、反应时间、反应温度、双氧水加量、催化剂量及溶剂等对丙烯环氧化反应的转化率、选择性等的影响,并初步探讨了无机钛硅原料合成的ＴＳ－１的再生性能。结果表明,对于丙烯环氧化反应,无机钛硅原料合成ＴＳ－１样品与经典法和修正法制取样品的催化性能相当;反应条件对丙烯环氧化反应     

聚苯胺对2,5—二巯基—1,3,4—噻二唑氧化还原反应的电化学？…

研究了聚苯胺（ＰＡn）膜电极在２,５－二巯基－１,３,４－噻二唑（ＤＭcＴ）溶液中电化学处理或浸泡后的循环伏安（ＣＶ）曲线的变化规律。实验结果表明,ＰＡn膜电极在 ＤＭcＴ溶液中进行电化学处理或浸泡过程可使ＤＭcＴ进入ＰＡn膜内部与ＰＡn形成复合物。ＰＡn对ＤＭcＴ的电化学催化作用可能和二者之间形成的电子给体－受体复合物有关。该复合物的电何尝氧化还原特性不同于ＰＡn对ＤＭcＴ的电化学催化作用可能和得之间形成的     

Structure of 6-Epiforsticine and Revision of the Stereochemistry of Forsticine

In the course of our investigation on Aconitum and Delphinium species, we have isolated a number of norditerpenoid and diterpenoid alkaloids from A. kuzsnezoffii and A. hemsleyanum var. pengzhouense1~6. We have found that a norditerpenoid alkaloid, 6-epiforsticine isolated from both plants shows a great deal of similarity to forsticine7 but significantly differed from the latter in its 13C NMR spectrum (Table l), suggesting that the alkaloids were a pair of epimers at C-6. The present comm…     

土壤环境中的硒对人和动物健康的影响

硒是人和动物必需的微量元素之一。土壤中的硒含量过多或过低，人和 动物都会出现地方性疾病。土壤中硒的含量与土壤母质、地形、气候条件和土壤条件性质等有关，调节土壤性质可以改善作物的含硒量。防治硒缺额症和硒中毒症，每天必需摄入适量的硒，以100－200μg为宜，但人体对硒的需要量也与食物成分有关。     

有害杂草的微量元素分析

紫茎泽兰和水葫芦均属有害杂草，大规模防治的有效方法还未找到，本文分析研究了采自昆明郊区的紫茎泽兰和滇池水域的水葫芦中微量元素的含量，为进一步开发利用这两种杂草提供科学依据。     

Low-temperature suspension polymerization of vinyl pivalate for the preparation of syndiotacticity-rich ultrahigh molecular weight poly(vinyl alcohol) microfibrils with high yield

To prepare ultrahigh molecular weight (UHMW) poly(vinyl pivalate) (PVPi) with high conversion and high linearity for a precursor of syndiotacticity-rich UHMW poly(vinyl alcohol) (PVA), vinyl pivalate (VPi) was suspension polymerized using a low-temperature initiator, 2,2'-azobis(2,4-dimethylvaleronitrile) (ADMVN), and the effects of polymerization conditions on the polymerization behavior and molecular structures of PVPi and PVA prepared by saponifying PVPi were investigated. Suspension polymerization was slightly inferior to bulk polymerization in increasing the molecular weight of PVA. In contrast, the former was superior in increasing the conversion of the polymer. Suspension polymerization of VPi at 25 °C by controlling various polymerization factors proved to be successful in obtaining PVA of UHMW (number-average degree of polymerization (P_n): 14,700-16,700), high syndiotactic diad content (62%), and of high yield (ultimate conversion of VPi into PVPi: 85-90%). In the case of bulk polymerization of VPi under the same conditions, maximum P_n, conversion of 15,800-17,000, and 25-35% were obtained, respectively. The degree of branching was lower and the P_n and syndiotacticity were higher with PVA prepared from PVPi polymerized at lower temperatures. All PVAs from PVPi suspension-polymerized at 25 °C were fibrous, with a high degree of crystallinity and orientation of the crystallites.     

The effect of influential data, model and method on the precision of univariate calibration

Building a calibration model with detection and quantification capabilities is identical to the task of building a regression model. Although commonly used by analysts, an application of the calibration model requires at first careful attention to the three components of the regression triplet (data, model, method), examining (a) the data quality of the proposed model; (b) the model quality; (c) the LS method to be used or a fulfillment of all least-squares assumptions. This paper summarizes these components, describes the effects of deviations from assumptions and considers the correction of such deviations: identifying influential points is the first step in least-squares model building, the calibration task depends on the regression model used, and finally the least squares LS method is based on assumptions of normality of errors, homoscedasticity, independence of errors, overly influential data points and independent variables being subject to error. When some assumptions are violated, the ordinary LS is inconvenient and robust M-estimates with the iterative method of reweighted least-squares must be used. The effects of influential points, heteroscedasticity and non-normality on the calibration precision limits are also elucidated. This paper also considers the proper construction of the statistical uncertainty expressed as confidence limits predicting an unknown concentration (or amount) value, and its dependence on the regression triplet. The authors' objectives were to provide a thorough treatment that includes pertinent references, consistent nomeclature, and related mathematical formulae to show by theory and illustrative examples those approaches best suited to typical problems in analytical chemistry. Two new algorithms, calibration and linear regression written in s-plus and enabling regression triplet analysis, the estimation of calibration precision limits, critical levels, detection limits and quantification limits with the statistical uncertainty of unknown concentrations, form the goal of this paper.