小鼠腹腔巨噬细胞诱生性一氧化氮的诱导合成

通过体外分离培养和体内注射ＴＦＮ－γ，研究了巨噬细胞内一氧化氮的诱导合成，体外２条件下，ＩＦＮ－γ能够诱导小鼠腹腔巨噬细胞合成一氧化氮，与对照组相比有显著差异。巨噬细胞内一氧化氮的诱导合成水平同ＩＦＮ－γ的剂量有关。ＴＮＦ－α能够显著增强ＩＦＮ－γ的诱导合成ＮＯ艇，ＩＦＮ－γ在体内可以增强巨噬细胞的一氧化氮合成能力。研究表明，，诱导巨噬细胞合成一氧化氮是一种非特异性免疫反应，ＩＦＮ－γ诱导免疫细胞     

Systematic analysis of genes required for synapse structure and function

Chemical synapses are complex structures that mediate rapid intercellular signalling in the nervous system. Proteomic studies suggest that several hundred proteins will be found at synaptic specializations. Here we describe a systematic screen to identify genes required for the function or development of Caenorhabditis elegans neuromuscular junctions. A total of 185 genes were identified in an RNA interference screen for decreased acetylcholine secretion; 132 of these genes had not previously been implicated in synaptic transmission. Functional profiles for these genes were determined by comparing secretion defects observed after RNA interference under a variety of conditions. Hierarchical clustering identified groups of functionally related genes, including those involved in the synaptic vesicle cycle, neuropeptide signalling and responsiveness to phorbol esters. Twenty-four genes encoded proteins that were localized to presynaptic specializations. Loss-of-function mutations in 12 genes caused defects in presynaptic structure.     

A 'dry' condensation origin for circumstellar carbonates

The signature of carbonate minerals has long been suspected in the mid-infrared spectra of various astrophysical environments such as protostars. Abiogenic carbonates are considered as indicators of aqueous mineral alteration in the presence of CO2-rich liquid water. The recent claimed detection of calcite associated with amorphous silicates in two planetary nebulae and protostars devoid of planetary bodies questions the relevance of this indicator; but in the absence of an alternative mode of formation under circumstellar conditions, this detection remains controversial. The main dust component observed in circumstellar envelopes is amorphous silicates, which are thought to have formed by non-equilibrium condensation. Here we report experiments demonstrating that carbonates can be formed with amorphous silicates during the non-equilibrium condensation of a silicate gas in a H2O-CO2-rich vapour. We propose that the observed astrophysical carbonates have condensed in H2O(g)-CO2(g)-rich, high-temperature and high-density regions such as evolved stellar winds, or those induced by grain sputtering upon shocks in protostellar outflows.     

郑州城市文化名片印记--"商"的讨论

城市间既有共性又有个性.离开个性,则难以找到一座城市文化名片独特的印记.郑州城市文化名片的印记是什么?寻根、少林、书院、军事、生态、饮食等诸多文化形态和文化理念,都难以涵盖郑州丰饶的文化积淀和绵长的文化传承.惟有"商",才是郑州城市文化名片印记的首选.     

Facilitation of Collaborative Management: Reflections From Practice

Collaborative management of natural resources requires that multiple stakeholders come together to negotiate agreements. Who is a stakeholder, what is the boundary and the definition of an issue, and who has legitimacy to convene are interrelated, systemic questions. To address this challenge, this paper provides a conceptual framework with nine Contextual Dimensions. A workshop on collaborative and conflict management of the fishery in Chile, designed and facilitated by the authors, serves as a case study where multiple stakeholders came together to vision desirable futures and explored organizational linkages that could accommodate the different agendas. The workshop is analyzed through a conceptual framework and some conclusions are drawn on the value of experiential learning and on the importance of the iterative consultations that must precede such collaborative management events.Member of the International Support Group (www.isglink.org), a community of practice dedicated to facilitating collaborative learning for natural resource management.     

Mutations in genes in the renin-angiotensin system are associated with autosomal recessive renal tubular dysgenesis

Autosomal recessive renal tubular dysgenesis is a severe disorder of renal tubular development characterized by persistent fetal anuria and perinatal death, probably due to pulmonary hypoplasia from early-onset oligohydramnios (Potter phenotype). Absence or paucity of differentiated proximal tubules is the histopathological hallmark of the disease and may be associated with skull ossification defects. We studied 11 individuals with renal tubular dysgenesis, belonging to nine families, and found that they had homozygous or compound heterozygous mutations in the genes encoding renin, angiotensinogen, angiotensin converting enzyme or angiotensin II receptor type 1. We propose that renal lesions and early anuria result from chronic low perfusion pressure of the fetal kidney, a consequence of renin-angiotensin system inactivity. This is the first identification to our knowledge of a renal mendelian disorder linked to genetic defects in the renin-angiotensin system, highlighting the crucial role of the renin-angiotensin system in human kidney development.     

Low dose oral cannabinoid therapy reduces progression of atherosclerosis in mice

Atherosclerosis is a chronic inflammatory disease, and is the primary cause of heart disease and stroke in Western countries. Derivatives of cannabinoids such as delta-9-tetrahydrocannabinol (THC) modulate immune functions and therefore have potential for the treatment of inflammatory diseases. We investigated the effects of THC in a murine model of established atherosclerosis. Oral administration of THC (1 mg kg(-1) per day) resulted in significant inhibition of disease progression. This effective dose is lower than the dose usually associated with psychotropic effects of THC. Furthermore, we detected the CB2 receptor (the main cannabinoid receptor expressed on immune cells) in both human and mouse atherosclerotic plaques. Lymphoid cells isolated from THC-treated mice showed diminished proliferation capacity and decreased interferon-gamma secretion. Macrophage chemotaxis, which is a crucial step for the development of atherosclerosis, was also inhibited in vitro by THC. All these effects were completely blocked by a specific CB2 receptor antagonist. Our data demonstrate that oral treatment with a low dose of THC inhibits atherosclerosis progression in the apolipoprotein E knockout mouse model, through pleiotropic immunomodulatory effects on lymphoid and myeloid cells. Thus, THC or cannabinoids with activity at the CB2 receptor may be valuable targets for treating atherosclerosis.     

β沸石的相对结晶度和Na2O含量对FCC催化剂催化性能的影响

β沸石的相对结晶度和Na2 O含量对引入 β沸石的FCC催化剂的催化性能有一定的影响。催化剂在 780℃下经 10 0 %水蒸气处理 4h后 ,影响FCC催化剂催化作用的主要因素是 β沸石的相对结晶度 ,Na2 O含量对催化剂初活性的影响不显著。催化剂在 780℃经 10 0 %水蒸气处理 17h后 ,β沸石的Na2 O含量对分子筛骨架稳定性的作用增大 ,从而导致引入高Na2 O含量的 β沸石的FCC催化剂的微反活性比低Na2 O含量样品的活性有所下降 ,同时使低碳烯烃和异构烷烃的产率降低。因此 ,引入FCC催化剂的 β沸石的相对结晶度要大于 80 % ,并要求其Na2 O含量低于 0 .1%。     

基于NFS的UNIX与Netware间数据传送

文中介绍在UNIX多用户系统与Novell网络服务器建立网络互连情况下 ,应用网络文件系统NFS使UNIX系统主机与Novell网络服务器之间实现数据的互备份。