合成气制乙醇铑催化剂中助剂的作用

促进型铑催化剂上,测定CO吸附的IR光谱和铑的分散度,结果表明:线吸附CO的谱带基本不变,桥CO谱带红移且变宽。变化顺序为Rh-Mn>Rb-Mn-Fe-Li>Rh-Fe>Rh-Li>Rh。该变化归因于助剂对吸附CO氧端络合而形成的η~2-CO物种,并可作为活性中心亲氧能力强弱的相对尺度,Rh·Mn/SiO_2上,测量CO/H_2的IR光谱,发现了归属于甲酰基的谱带;说明甲酰基是反应中间物,并测定各催化剂活性和选择性,基于这些结果和蔡启瑞等曾提出的氢助解离乙烯酮机理,能较合理地探讨了助剂的协合催化作用,本研究再次为上述机理提供另一重要实验证据。     

催化剂分子设计专家系统中数据库和知识库的建立

从建造专家系统的理论体系出发，结合作者以前在计算机辅助催化剂分子设计方面所做的工作，确立了复合催化剂组分子设计专家系统的基本结构，并探讨了这一系统的任务功能、体系结构与支持界面、性质数据库与知识规则库的建立．以甲烷氧化偶联反应为例，说明了数据库的构成和领域知识的分类以及相应的知识表示技术．     

甲烷氧化偶联Ba－ZrO_2催化剂的研究

发现掺有碱土金属组份的ＺｒＯ２样品形成ＡＺｒＯ３相，其对甲烷氧化偶联反应显示出相当好的催化活性和选择性（其中Ａ＝Ｃａ，Ｓｒ，Ｂａ，尤以Ｂａ为佳）．大量ＢａＣＯ３相的存在有利于进一步提高催化剂的选择性；对于９０ｍｏｌ％Ｂａ－ＺｒＯ２催化剂在７５０℃，６００００ｍｌ·ｇ－１·ｈ－１，ＣＨ４：Ｏ２：Ｎ２＝３．８：１．０：９．０（摩尔比）的条件下，Ｃ２烃选择性为５６．９％，Ｃ２烃得率达１７．２％．讨论了ＢａＣＯ３对几种催化剂的促进作用．     

Phosphorylation of DARPP-32 by Cdk5 modulates dopamine signalling in neurons

The physiological state of the cell is controlled by signal transduction mechanisms which regulate the balance between protein kinase and protein phosphatase activities. Here we report that a single protein can, depending on which particular amino-acid residue is phosphorylated, function either as a kinase or phosphatase inhibitor. DARPP-32 (dopamine and cyclic AMP-regulated phospho-protein, relative molecular mass 32,000) is converted into an inhibitor of protein phosphatase 1 when it is phosphorylated by protein kinase A (PKA) at threonine 34. We find that DARPP-32 is converted into an inhibitor of PKA when phosphorylated at threonine 75 by cyclin-dependent kinase 5 (Cdk5). Cdk5 phosphorylates DARPP-32 in vitro and in intact brain cells. Phospho-Thr 75 DARPP-32 inhibits PKA in vitro by a competitive mechanism. Decreasing phospho-Thr 75 DARPP-32 in striatal slices, either by a Cdk5-specific inhibitor or by using genetically altered mice, results in increased dopamine-induced phosphorylation of PKA substrates and augmented peak voltage-gated calcium currents. Thus DARPP-32 is a bifunctional signal transduction molecule which, by distinct mechanisms, controls a serine/threonine kinase and a serine/threonine phosphatase.     

随机扰动下DNA三核苷酸重复序列的弯曲和柔性

利用统计力学模型讨论了与人类遗传病有关的DNA三核苷酸重复序列的弯曲和柔性,提出随机成动模型来近似表示DNA序列和蛋白质的相互作用,发现弯曲很小的三核苷重复序列在有随机扰动的情况下,可以出现大角度的弯曲,且随扰动强度的加大出现大角度弯曲的概率增加,求出了十二种三核苷重复序列的柔性及其长度依赖,发现当序列长度大于150 bp时,柔性的变化开始显,CTG和CGG具有最大的柔性,研究了柔性在有随机扰动时下的变化,发现在序列上不同位置施加扰动,柔性的变化程度不同,对于600bp长的序列,在390bp处的柔性变化程度最大。     

Inhibition of Rho-associated kinase relieves C5a-induced proteinuria in murine nephrotic syndrome

Childhood nephrotic syndrome is mainly caused by minimal change disease which is named because only subtle ultrastructural alteration could be observed at electron microscopic level in the pathological kidney. Glomerular podocytes are presumed to be the target cells whose protein sieving capability is compromised by a yet unidentified permeability perturbing factor. In a cohort of children with non-hereditary idiopathic nephrotic syndrome, we found the complement fragment C5a was elevated in their sera during active disease. Administration of recombinant C5a induced profound proteinuria and minimal change nephrotic syndrome in mice. Purified glomerular endothelial cells, instead of podocytes, were demonstrated to be responsible for the proteinuric effect elicited by C5a. Further studies depicted a signaling pathway involving Rho/Rho-associated kinase/myosin activation leading to endothelial cell contraction and cell adhesion complex breakdown. Significantly, application of Rho-associated kinase inhibitor, Y27632, prevented the protein leaking effects observed in both C5a-treated purified endothelial cells and mice. Taken together, our study identifies a previously unknown mechanism underlying nephrotic syndrome and provides a new insight toward identifying Rho-associated kinase inhibition as an alternative therapeutic option for nephrotic syndrome.     

铑催化剂上CO的吸附态及其加氢反应

用红外光谱法测定表明：各种硅胶负载仲进型铑催化剂上，线ＣＯ／桥ＣＯ红外吸收强度比值与金属助剂（Ｍ）的关系变化顺序为（５０：１）（Ｒｈ－Ｍｎ）〉（２２：１）（Ｒｈ－Ｌｉ）〉（９．１：１）（Ｒｈ－Ｍｎ－Ｆｅ－Ｌｉ）〉（３．５：１）（Ｒｈ－Ｆｅ）〉２．８：１）（Ｒｈ）。在各种Ｒｈ－Ｍ／ＳｉＯ２催化剂上，线、桥ＣＯ吸附态的加氢原位ＦＴＩＲ跟踪实验表明：随着加氢的进行，线ＣＯ／桥ＣＯ吸收强度比值均逐渐减少…     

改进型铜基甲醇合成催化剂的制备研究

在三组分铜基催化剂Ｃｕ－Ｚｎ－Ａｌ中添加少量第四组分金属氧化物助剂ＭＯ＿ｘ，制得改进型四组分铜基甲醇合成催化剂Ｃｕ－Ｚｎ－Ａｌ－Ｍ（ＸＨ４０２）；５．０ＭＰａ压力下的活性评价结果表明ＸＨ４０２催化剂合成甲醇时空得率比工业甲醇合成催化剂Ｃ３０１提高２５％。催化剂的ＸＲＤ表征显示，工作态ＸＨ４０２催化剂的活性相特征峰２θ＝４３．３２°的强度比Ｃ３０１的提高约３０％。