Let-7 in Cardiovascular Diseases,Heart Development and Cardiovascular Differentiation from Stem Cells

The let-7 family is the second microRNA found in C. elegans. Recent researches have found it is highly expressed in the cardiovascular system. Studies have revealed the aberrant expression of let-7 members in cardiovascular diseases, such as heart hypertrophy, cardiac fibrosis, dilated cardiomyopathy (DCM), myocardial infarction (MI), arrhythmia, angiogenesis, atherosclerosis, and hypertension. Let-7 also participates in cardiovascular differentiation of embryonic stem cells. TLR4, LOX-1, Bcl-xl and AGO1 are by now the identified target genes of let-7. The circulating let-7b is suspected to be the biomarker of acute MI and let-7i, the biomarker of DCM. Further studies are necessary for identifying the gene targets and signaling pathways of let-7 in cardiovascular diseases. Let-7 might be a potential therapeutic target for cardiovascular diseases. This review focuses on the research progresses regarding the roles of let-7 in cardiovascular development and diseases.     

一种兼容有铅和无铅焊锡丝用的无卤素助焊剂

研制了一种兼容无铅和中高度数的有铅焊料的有芯焊线用免清洗无卤素助焊剂,该焊剂以复合有机酸和有机胺复配为活性剂的主要成分。该产品性能测试参照国家标准GB/T 9491-2002,其中扩展率大于80%;经过恒温恒湿箱测试96h后表面绝缘阻抗大于1011Ωmin。本产品具有焊接效果良好,无卤素,环保,无腐蚀,焊后免清洗等特点。     

渤海湾盆地乐亭凹陷下第三系含油气系统

为深入分析渤海湾盆地乐亭凹陷油气生成条件及成藏规律，对其下第三系含油气系统进行了综合研究,结果表明：区内存在丰富而成熟的烃源岩，暗色泥岩分布范围广且具备生烃能力，沙三中、下段泥质岩以及沙一下段泥质岩均具有良好的封盖性；发育有下生上储、自生自储2种生储盖组合形式；存在有断块(鼻)圈闭、岩性圈闭、地层圈闭、复合圈闭等多种圈闭类型；油气以砂岩疏导层供油、断层供油和不整合面供油3种方式进行运移和聚集；下第三系含油气系统经历了隆升褶皱变动、断陷、沉降3个主要阶段。以源岩潜量指数(SPI)为参数对含油气系统进行了评价，指出以侧向运移为主的自生自储式成油组合具备有利的成油条件，以垂向运移为主的下生上储式成油组合成藏条件次之。      

Walsh transform applied to digital filtering

The filtering process can also be implemented by other transformations than the well-known Fourier transformation. The paper is devoted to the one-dimensional (1-D) and two-dimensional (2-D) digital filtering process by the use of 1-D and 2-D discrete Walsh transforms (DWTs). Particularly, the optimum Walsh filter problem with one- and two-dimensional discrete data with emphasis on reduction of the computational requirements is considered. The optimum Walsh filters which are determined are based upon some modified minimum-mean-square-error criterion. Two basic classes of signals, which are to be filtered, have been taken into account: periodic signals and stationary random processes. Two computational examples are given.