Therapeutic Potential of Highly Selective A3 Adenosine Receptor Ligands in the Central and Peripheral Nervous System

Ligands of the G_i protein-coupled adenosine A₃ receptor (A₃R) are receiving increasing interest as attractive therapeutic tools for the treatment of a number of pathological conditions of the central and peripheral nervous systems (CNS and PNS, respectively). Their safe pharmacological profiles emerging from clinical trials on different pathologies (e.g., rheumatoid arthritis, psoriasis and fatty liver diseases) confer a realistic translational potential to these compounds, thus encouraging the investigation of highly selective agonists and antagonists of A₃R. The present review summarizes information on the effect of latest-generation A₃R ligands, not yet available in commerce, obtained by using different in vitro and in vivo models of various PNS- or CNS-related disorders. This review places particular focus on brain ischemia insults and colitis, where the prototypical A₃R agonist, Cl-IB-MECA, and antagonist, MRS1523, have been used in research studies as reference compounds to explore the effects of latest-generation ligands on this receptor. The advantages and weaknesses of these compounds in terms of therapeutic potential are discussed.     

接枝改性碳酸钙及其在聚合物中的应用研究

介绍了近年来碳酸钙表面接枝改性的研究进展,讨论了自由基接枝聚合、辐照接枝聚合和力化学表面接枝聚合及偶联剂预处理与辐照并用接枝聚合改性方法。其中重点讨论了最新研究的偶联剂预处理与辐照并用接枝改性纳米碳酸钙的方法。用此方法制备的聚合物/纳米碳酸钙纳米复合材料在其他力学性能基本不变的情况下,大幅度提高了其缺口冲击强度和断裂伸长率。指出了碳酸钙表面接枝改性应向着提高接枝单体量和采用弹性体单体方面发展。     

硅凝胶体系中不同结构羧酸钾对草酸钙结晶的影响

采用扫描电子显微镜(SEM)和X射线衍射(XRD)方法研究了硅凝胶体系中不同种类羧酸钾对草酸钙(CaC₂O₄)晶体生长的调控作用. 加入一元醋酸钾(KOAc)只生成一水草酸钙(COM)晶体; 三元柠檬酸钾(K₃Cit)和四元乙二胺四乙酸二钾(K₂EDTA)可诱导二水草酸钙(COD)形成, 且随着其浓度增加, 对COD的诱导能力增加, 而二元酒石酸钾(K₂Tart)同时诱导了COM, COD和三水草酸钙(COT)生成. 随着结晶温度降低, 多元酸钾可以进一步减小COM晶体的比表面积, 增加COD的百分含量, 但K₂Tart诱导COT的能力减弱. 由于诱导COD和COT晶体形成、减小COM的比表面积均有利于防止草酸钙尿石的形成, 因此, 多元羧酸钾可用于草酸钙结石的预防和治疗.     

羧甲基壳聚糖与钙离子络合作用的研究

羧甲基壳聚糖(carboxymethyl chitosan,CMCS)是壳聚糖Chitosan经化学改性得到的水溶性衍生物,由于羧基的引入,络合金属离子的能力及反应速度大大提高[1-6],在医药、化工、环保等领域有着广泛的应用前景。本文研究了羧甲基壳聚糖与Ca2 络合的条件,着重探讨了Pb2 在不同条件下对络合反应的影响,以期扩大羧甲基壳聚糖的应用范围。1材料与方法1.1仪器与试剂羧甲基壳聚糖(自制),其它试剂均为国产优级纯。TAS-986G原子吸收分光光度计;SX5-12箱式电阻炉;GL-20B高速冷冻离心机;Ori-on818型pH测试计。1.2实验方法1.2.1羧甲基壳聚糖与Ca2 络合…     

白云石制备似立方体状方解石型碳酸钙晶体及其机理研究

以轻烧白云石粉、氯化铵和二氧化碳为原料,在未使用晶型控制剂的情况下,通过蒸氨-沉钙过程制备出了似立方体状碳酸钙。研究了反应温度、溶液中钙离子浓度、通气速率、搅拌速度以及陈化时间对碳酸钙中方解石相含量以及晶体形貌的影响,并探索了沉钙反应的晶型控制机理。结果表明,在反应温度40 ℃、钙离子浓度0.05 mol/L、通碳速率100 mL/min、搅拌速度400 r/min和陈化时间2 h的条件下,制备出形貌规整、粒径分布均匀的似立方体状碳酸钙,平均粒径为5~10 μm。该研究为提升白云石的使用价值、生产高附加价值的碳酸钙产品,以及提高白云石资源的利用率提供理论基础。     

添加CaSO4·2H2O为晶种制备磷石膏半水硫酸钙晶须

以固体废弃物磷石膏为原料,在传统常压醇水热法的基础上添加CaSO₄·2H₂O为晶种制备半水硫酸钙晶须。采用单因素试验法探究了晶种含量、丙三醇含量和磷石膏质量分数对晶须结构和形貌的影响,确定晶须的最佳制备工艺条件。采用SEM和XRD对样品进行表征分析,实验结果表明:添加CaSO₄·2H₂O晶种制备晶须的长径比(49.29)比只添加丙三醇的样品的长径比(30.99)提高了近60%;当丙三醇与水的体积比(V)为1、晶种含量为1%、磷石膏质量分数为5%时制备的晶须的平均直径为0.65 μm,长径比达到了62.15,晶须的尺寸均匀。这说明添加1%CaSO₄·2H₂O晶种、V为1的丙三醇和质量分数为5%的磷石膏在常压下能制备出高长径比和尺寸均匀的半水硫酸钙晶须。     

高效液相色谱法同时测定六种二氢吡啶类钙拮抗剂血药浓度

This paper presents the use of an HPLC method to assay nifedipine,nitrendipine,nimoldipine,nisoldip-ine,felodipine, m-nisoldipine concentration in human plasma simultaneously。 Separation was obtained using ODS column and mobile phase of acetonitrile-water(60:40,V/V)with flow rateof 1 mL/min。They were monitored with UV detector at 238 nm,The retention times for 6 drugs mentionedabove were 5.08,7.50,8.57,10.0,11. 91 and 12. 95 min,respectively。The recoveries were all 97%。     

流化床煤气化炉内脱硫的研究Ⅰ．台式流化床煤气化的炉内脱硫试验

采用台式流化床煤气化装置，研究了影响炉内脱硫效率的因素。炉内脱硫对高硫煤特别有效，脱硫效率可达９０％以上。所采用的二种石灰石和一种白云石脱硫效率相近，按Ｃａ／Ｓ比比较则白云石稍好些。虽然脱硫效率随Ｃａ／Ｓ比增加而增加，但当Ｃａ／Ｓ比达到３后几乎不再增加。存在一个最佳脱硫操作温度。在非焙烧区，脱硫率随压力增加而下降，而在焙烧区脱硫率和压力几乎无关。测定了脱硫剂脱硫前后的孔容积分布，发现脱硫之后１～３０ｎｍ的孔容显著减少。     

偏硼酸钙改性al-mcm-41催化剂的表征及催化性能

al-mcm-41分子筛;偏硼酸钙;催化性能;乙氧基化     

Synthesis and thermal characterization of copper and calcium mixed phosphates

A series of compounds with composition of Ca_1–xCu_xHPO₄, where x varied from 0.05 to 0.5 were synthesized by precipitation method. The compounds were characterized by elemental analysis, X-ray diffraction, infrared spectroscopy, scanning electron microscopy, and thermogravimetry. The chemical stabilities of solids were investigated at several pH. Elemental analysis of copper, calcium and phosphorus are in agreement with the proposed composition. The formation of lamellar phosphates was evidenced. The stability of the set of compounds was better for samples with high copper content.