给陌生人打个电话《比邻》

一个人的城市里,朋友的帮助,家人的关爱,这些都是必不可少的。但忙碌了一天,回到空荡荡的家里,可曾寂寞？可曾无聊？重复的每一天,青春的激情去哪了？这时候,是不是很希望有一点惊喜发生,哪怕是来自陌生人的一声问候,一句关怀,年轻的心就可以有所慰藉。或许,一款叫《比邻》的APP可以帮你。     

Synthesis of the Sulphonate and Phosphonate Derivatives of Mercaptoacetyltriglycine. X-Ray Crystal Structure of Na(2)[ReO(Mercaptoacetylglycylglycylaminomethanesulphonate)].3H(2)O

Mercaptoacetyltriglycine forms complexes with (186/188)Re and (99m)Tc radionuclides that are useful in nuclear medicine because they are substrates of the renal anion transport system. However, the renal clearance of [MO(MAG(3))](2-)(MAG(3) = penta-anionic form of mercaptoacetyltriglycine, M = Re, Tc) complexes are less than ideal. Organic sulphonates are also transported by the renal anion transport system and phosphonates are similar to sulphonates in size and shape. In an effort to develop new ligands that form Re and Tc complexes and have improved renal clearances compared to [MO(MAG(3))](2-) complexes, the sulphonate and phosphonate derivatives of mercaptoacetyltriglycine were synthesized. The dianion [ReO(MAG(2)-AMS)](2-) (MAG(2)-AMS = penta-anionic form of mercaptoacetylglycylglycylaminomethanesulphonic acid) was prepared for characterization by exchange reaction of ReOCl(3)(Me(2)S)(OPPh(3)) and isolated as the disodium salt. The structure of Na(2)[ReO(MAG(2)-AMS)].3H(2)O (6) was determined by X-ray diffraction. The coordination geometry is pseudo square pyramidal, with the nitrogen and sulfur donor atoms forming a square base and the oxo ligand at the apex. The deprotonated sulphonate group has a syn conformation with respect to the oxo ligand. The renal clearances of [(99m)TcO(MAG(2)-AMS)](2-) and [(99m)TcO(MAG(2)-AMP)](3-) were similar in rats and suggest that the difference in total charge between the SO(3) (-) and PO(3) (2-) groups is not important to renal clearance. However, their renal clearances were 40-50% less than that of [(99m)TcO(MAG(3))](2-) suggesting that the size and shape of the large tetrahedral SO(3) (-) and PO(3) (2-) groups of [(99m)TcO(MAG(2)-AMS)](2-) and [(99m)TcO(MAG(2)-AMP)](3-) inhibit recognition by the renal transport system compared to the small planar CO(2) (-) group of [(99m)TcO(MAG(3))](2-).     

吡唑-4-基烷基酮衍生物的合成、结构和除草活性

原卟啉原氧化酶(protox)最近被证实是已知光动力作用除草剂化合物的靶标。如许多其他除草剂的结合位置一样,原卟啉原氧化酶是几种化学结构上三级交叉类型的除草剂(图1)的酶靶标,包括二苯基醚类[如乙氧氟草醚(Oxyfluorfen),Ⅰa;三氟羧草醚(acifluorfen),Ⅰb]、噁二唑类[如噁草酮(Oxadiazon)、吡啶衍生物类(如LS82-556,(S)-2,6-二甲基-N-(α-甲基苄基)-5-丙酰基烟酰胺];吡唑-4-腈类[如M&B39279,5-氨基-1-(2,6-二氯-4-三氟甲基)苯基吡唑-4-腈,Ⅱa]和推测可能是吡唑-4-腈的类似物(如Ⅲa,表1)。可以认     

尿素嵌入法制备纤维素氨基甲酸酯的研究

探讨了尿素嵌入法制备纤维素氨基甲酸酯(CC)的生产工艺。指出:选用聚合度为450~625、α-纤维素含量大于90/的纤维素浆粕,用14/~16/的氢氧化钠溶液,于40~50℃条件下活化处理30~40min后,与尿素以1∶2~3的比例混合,在137℃的二甲苯体系中反应2~3h,便可得到含氮量为2.4/~3.5/的纤维素氨基甲酸酯产物。该产物在氢氧化钠溶液中可形成良好的稳定溶液,过滤性好,可直接用于纺丝。     

Photoresponsive dendritic azobenzene peptides

Two dendritic peptides containing a branched lysine core and up to eight azobenzene moieties in the periphery were synthesized on solid support employing the omega-amino acid 4-(aminomethyl)phenylazobenzoic acid. With an additional peptidic tail consisting of an oligolysine portion, water solubility was achieved for the dendrimers, which allowed for the characterization of the cis/trans photoisomerization of the dendritic azobenzene species in both organic and aqueous media. Despite the interactions between the chromophores, which occur particularly in aqueous media, at higher dilution the photoisomerization process was found to proceed to extents that should permit photomodulation of molecular recognition processes between ligands grafted to the photosensitive azobenzene units and receptor molecules.     

Chemical inhibitors when timing is critical: a pharmacological concept for the maturation of T cell contacts

Cellular signal transduction proceeds through a complex network of molecular interactions and enzymatic activities. The timing of these molecular events is critical for the propagation of a signal and the generation of a specific cellular response. To define the timing of signalling events, we introduce the combination of high-resolution confocal microscopy with the application of small-molecule inhibitors at various stages of signal transduction in T cells. Inhibitors of Src-family tyrosine kinases and actin dynamics were employed to dissect the role of the lymphocyte-specific tyrosine kinase Lck in the formation and maintenance of T cell receptor/CD3-dependent contacts. Anti-CD3epsilon-coated coverslips served as a highly defined stimulus. The kinetics of the recruitment of the yellow fluorescent protein-tagged signalling protein ZAP-70 were detected by high-resolution confocal microscopy. The analysis revealed that at 5 min after receptor engagement, Lck activity was required for maintenance of contacts. In contrast, after 20 min of receptor engagement, the contacts were Lck-independent. The relevance of the timing of inhibitor application provides a pharmacological concept for the maturation of T cell-substrate contacts.     

POE和成核剂协同增韧聚丙烯的研究

研究了乙烯-辛烯共聚物(POE)和β-成核剂TMB-5协同增韧聚丙烯(PP)的作用效果,通过对比相同比例的PP/POE和PP/POE/TMB-5共混物对熔体流动性、拉伸屈服强度和低温下缺口、无缺口冲击强度的影响,发现加入成核剂TMB-5确实能够协同POE增韧PP,使低温下的缺口冲击强度显著提高;SEM研究表明,POE以约2μm平均球径均匀地分散在PP连续相中;DSC和WAXD研究表明,TMB-5能够使PP的部分α晶型转变为β晶型,从而协助POE增韧PP。     

杀螟硫磷原药和制剂气相色谱测定法的协作研究

世界卫生组织(WHO)于1973年首次把杀螟硫磷(fenitrothion)编入农药规格手册。有效成份的分析采用滴定法,该法基于杀螟硫磷在酸性溶液中被锌还原,然后用亚硝酸钠滴定还原产物胺。方法包括原药及其可湿性粉剂的测定。这一方法并不是专一的而且费时。在WHO杀虫剂化学与规格专家委员会1977年会议上,J.W.Miles和D.L.Mount     

由煤地下气化生产电力、代用天然气和合成气的费用估计

对煤地下气化的三个可能的应用:(1)应用低热值煤气复合循环的90万瓩的发电厂;(2)每天生产1.55亿立方英尺热值为954英热单位/立方英尺煤气的代用天燃气工厂;(3)每天生产3.88亿立方英尺适于进一步化学转化的合成气的工厂——作了概念设计。设计以Laramie能源研究中心用竖井连通法地下气化所得次沥青煤的实验结果为依据。三个厂相应的投资为423、376、334百万美元(1978年第一季度价)。产品价格为下列因素的函数:债务/股份资本比、资本的利润率、煤的费用和工厂因数。采用债务/股份资本比为70/30,煤的费用为每短吨五美元,债务利息为9%,缴税后的资本利润率为15%,这时电力价格为每度电2.4美分(工厂因数为70%),代用天燃气价格为每10~6英热单位2.89美元,合成气价格为每10~6英热单位2.48美元(工厂因数均为90%)。这三个工厂的总热效率分别为24,38,40%(基于原始煤)。