回复与再结晶退火对新型HSn701黄铜组织及性能的影响

设计了一种新型HSn70-1黄铜合金,其冷拉拔加工率为55%.应用偏光显微镜、X射线衍射仪、扫描电子显微镜、显微硬度计、万能材料试验机和电化学工作站等设备,研究了不同的退火温度对新型合金显微组织和性能的影响.结果表明：加入少量Sn,Al,P,Ni合金元素构成了新型HSn70-1合金,合金元素以固溶体的形式存在于晶粒内部,其组织为α单相;合金在不同温度下保温2 h,200℃时发生应变时效,300~450℃为再结晶过程,450~550℃为晶粒长大阶段,550~600℃晶粒基本完全长大.随着退火温度的升高,合金的硬度、抗拉强度和屈服强度逐渐降低并趋于缓慢,其伸长率变化相反;合金自腐蚀电流密度、失重率逐渐降低并趋于稳定;开路电位逐渐变大,最后趋于稳定,新型HSn70-1黄铜的耐腐蚀性逐渐变好.     

湘西4月龄山羊羔羊生长性能的品种差异

测定4月龄波尔山羊、南江黄羊、波尔山羊×南江黄羊F1代羔羊在当地饲养水平下的采食量和日增重差异.结果表明：3个品种羔羊的每周和全期青饲料日干物质采食量差异不显著（P>0.05）;而在正式试验期第1周南江黄羊平均日增重显著高于波尔山羊×南江黄羊F1代（P<0.05）,在第2周南江黄羊平均日增重却显著低于波尔山羊×南江黄羊F1代（P<0.05）;在第3周3个品种平均日增重水平差异不显著（P>0.05）,全期各品种平均日增重差异也不显著（P>0.05）.说明在湘西当地饲养水平下,三品种山羊羔羊的生长性能相近,波尔山羊的杂交优势不显著.     

The roles of poly(ADP-ribose)-metabolizing enzymes in alkylation-induced cell death

Poly(ADP-ribose) (PAR) has been identified as a DNA damage-inducible cell death signal upstream of apoptosis-inducing factor (AIF). PAR causes the translocation of AIF from mitochondria to the nucleus and triggers cell death. In living cells, PAR molecules are subject to dynamic changes pending on internal and external stress factors. Using RNA interference (RNAi), we determined the roles of poly(ADP-ribose) polymerases-1 and -2 (PARP-1, PARP-2) and poly(ADP-ribose) glycohydrolase (PARG), the key enzymes configuring PAR molecules, in cell death induced by an alkylating agent. We found that PARP-1, but not PARP-2 and PARG, contributed to alkylation-induced cell death. Likewise, AIF translocation was only affected by PARP-1. PARP-1 seems to play a major role configuring PAR as a death signal involving AIF translocation regardless of the death pathway involved. Received 7 November 2007; received after revision 19 December 2007; accepted 21 December 2007 O. Cohausz, C. Blenn: These two authors contributed equally to this work.     

Endocrine-dependent expression of circadian clock genes in insects

Current models state that insect peripheral oscillators are directly responsive to light, while mammalian peripheral clock genes are coordinated by a master clock in the brain via intermediate factors, possibly hormonal. We show that the expression levels of two circadian clock genes, period (per) and Par Domain Protein 1 (Pdp1) in the peripheral tissue of an insect model species, the linden bug Pyrrhocoris apterus, are inversely affected by contrasting photoperiods. The effect of photoperiod on per and Pdp1 mRNA levels was found to be mediated by the corpus allatum, an endocrine gland producing juvenile hormone. Our results provide the first experimental evidence for the effect of an endocrine gland on circadian clock gene expression in insects. Received 31 October 2007; received after revision 7 January 2008; accepted 9 January 2008 D. Dolezel, L. Zdechovanova: These authors contributed equally to this work.     

Cholera toxin structure, gene regulation and pathophysiological and immunological aspects

Many notions regarding the function, structure and regulation of cholera toxin expression have remained essentially unaltered in the last 15 years. At the same time, recent findings have generated additional perspectives. For example, the cholera toxin genes are now known to be carried by a non-lytic bacteriophage, a previously unsuspected condition. Understanding of how the expression of cholera toxin genes is controlled by the bacterium at the molecular level has advanced significantly and relationships with cell-density-associated (quorum-sensing) responses have recently been discovered. Regarding the cell intoxication process, the mode of entry and intracellular transport of cholera toxin are becoming clearer. In the immunological field, the strong oral immunogenicity of the non-toxic B subunit of cholera toxin (CTB) has been exploited in the development of a now widely licensed oral cholera vaccine. Additionally, CTB has been shown to induce tolerance against co-administered (linked) foreign antigens in some autoimmune and allergic diseases. Received 25 October 2007; accepted 12 December 2007     

特大规模组合电路测试数据产生方法研究

针对特大规模组合电路和全扫描设计电路提出了一种高速测试生成方法。该方法采用有限回溯测试模式产生方法生成测试码,采用ｎ（机器字长）个测试码并行的单故障传播方法模拟验证测试覆盖。测试生成与故障模拟为ｎ对１紧耦合集成方式。该方法运行１０个Ｂｅｎｃｈｍａｒｋ电路,取得了低测试长度、高故障覆盖、高效率的良好效果。     

Cancer and blood coagulation

In human patients, blood coagulation disorders often associate with cancer, even in its early stages. Recently, in vitro and in vivo experimental models have shown that oncogene expression, or inactivation of tumour suppressor genes, upregulate genes that control blood coagulation. These studies suggest that activation of blood clotting, leading to peritumoral fibrin deposition, is instrumental in cancer development. Fibrin can indeed build up a provisional matrix, supporting the invasive growth of neoplastic tissues and blood vessels. Interference with blood coagulation can thus be considered as part of a multifaceted therapeutic approach to cancer. Received 30 November 2005; received after revision 7 February 2005; accepted 8 February 2006     

The ubiquitin-specific protease USP25 interacts with three sarcomeric proteins

The biological functions of the more than one hundred genes coding for deubiquitinating enzymes in the human genome remain mostly unknown. The USP25 gene, located at 21q11.2, encodes three protein isoforms produced by alternative splicing. While two of the isoforms are expressed nearly ubiquituously, the expression of the longer USP25 isoform (USP25m) is restricted to muscular tissues and is upregulated during myogenesis. USP25m interacts with three sarcomeric proteins: actin alpha-1 (ACTA1), filamin C (FLNC), and myosin binding protein C1 (MyBPC1), which are critically involved in muscle differentiation and maintenance, and have been implicated in the pathogenesis of severe myopathies. Biochemical analyses demonstrated that MyBPC1 is a short-lived proteasomal substrate, and its degradation is prevented by over-expression of USP25m but not by other USP25 isoforms. In contrast, ACTA1 and FLNC appear to be stable proteins, indicating that their interaction with USP25m is not related to their turnover rate. Received 7 November 2005; received after revision 7 January 2006; accepted 13 January 2006     

Functional interactions of protein kinase A and C in signalling networks: a recapitulation

On the basis of evidence collected from the literature, we propose a general model by which protein kinase (PK) A and the different PKC isoforms can inversely affect cell growth. Molecular switches, which are able to direct the signal towards antiproliferative or mitogenic pathways, are the different isoforms of Raf and PKC. Conflicting data are also reported and discussed in an attempt to reconcile them. Received 10 November 2005; received after revision 28 December 2005; accepted 3 January 2006