南大洋碳循环研究进展

本文介绍了南大洋碳循环的国内外研究动态及最新研究进展,包括南大洋的初级生产力水平,DOC、POC贮库,有机碳的输出通量及其深海沉积通量,讨论了限制南大洋初级生产力的最新研究进展。南大洋初级生产力总体水平较低,但在陆架区、海冰边缘区（MIZ）以及极锋等特殊的水文区域有较高的生物生产力。南极的生产力限制主要认为是Fe限制,但在[Si(OH)4]的浓度梯度（极锋附近的[Si(OH)4]剧烈变化带,其浓度以0.25-0.56uM/km速度向南发展）以北的南大洋（[Si(OH)4]浓度为1-15uM),形成Si限制。对极锋区浮游植物水华的观测表明,极锋区的浮游植物是受一系列过程的调节,包括：光、捕食、硅酸盐和Fe,这样,只包含一种机制的模式将是不充分的。南大洋POC、DOC贮库在春夏季增长极快,但夏季POC输出通量一直很小,直到秋季才突然增大。南大洋的叶绿素、初级生产速率、POC贮量以及有机碳的输出通量在时间上解耦合,反映了南大洋生态系统的特殊性。另一方面,由于存在许多锋结构及锋面系统,并且有广大的季节海冰区存在,南大洋包含有许多功能各异的亚系统,这些亚系统在碳循环中的作用各不相同,造成了南大洋碳循环的复杂性。今后的研究仍然需要更深入地了解南大洋碳循环的机制,以及南大洋碳循环在全球变化过程中的影响及反馈。     

Constructing Failure: Leonard Hayflick,Biomedicine, and the Problems with Tissue Culture

By examining the use of tissue culture in post-war American biomedicine, this paper investigates how scientists experience and manage failure. I study how Leonard Hayflick forged his new definition of failure and ways of managing it by refuting Alexis Carrel's definition of failure alongside his theory of the immortality of cultured cells. Unlike Carrel, Hayflick claimed that every vertebrate somatic cell should eventually die, unless it transformed into a tumour cell. This claim defined cell death, which had been a problem leading to a laboratory failure, as a normal phenomenon. On the other hand, permanent life, which had been considered a normal cellular characteristic, became a major factor causing scientific failure, since it implied malignant transformation that scientists hoped to control. Hayflick then asserted that his cell strains and method would partly enable scientists to manage this factor—especially that occurred through viral infection—alongside other causes of failure in routine tasks, including bacterial contamination. I argue that the growing biomedical enterprise fostered this work of Hayflick's, which had repercussions in both his career and the uses of cells in diverse investigations. His redefinition of failure in the age of biomedicine resulted in the broad dissemination of his cells, medium, and method as well as his long struggle with the National Institutes of Health (NIH), which caused his temporarily failed career.     

Carbon dioxide sensitivity of pulmonary receptors in the frog

Summary Pulmonary mechano-receptors have been found in the frog lung that are sensitive to CO₂ concentrations in the lungs and airways comparable to the physiological levels recorded in frogs. These results support the suggestion that a pulmonary receptor with distinct mechano- and chemosensitive properties may represent the functional precursor of the more specialized pulmonary receptor types which have evolved in birds and mammals.Supported by grants from N. R. C. C. and the Presidents Fund, University of British Columbia.     

锂离子电池失效的快速判定

通过锂离子单体电池的循环寿命实验,分析了该电池的充放电电流,电压以及内阻随循环次数的老化特性.研究发现,随着充放电次数的增加,电池在恒流阶段充入的容量占总容量的百分比的变化趋势和电池内阻变化相一致,因此可以根据恒流充电的时间来快速判定电池的衰减程度.     

Carbon dioxide fixation by the achloric algaPrototheca zopfii

Riassunto Estratti cellulari dell'alga acloricaPrototheca zopfii fissano anidride carbonica esclusivamente sul fosfoenolpiruvato. La reazione è stimolata da MgCl₂ e MnCl₂ ma non da IDP o ADP.     

Failure of ascorbic acid to influence brain catecholamines in the guinea-pig

Summary Lack of dietary ascorbic acid lowered plasma levels of ascorbic acid but failed to change levels of brain norepinephrine or dopamine.Investigators adhered during the research described in this report to the policy set forth in the Guide for the Care and Use of Laboratory Animals by the Committee on Revision of the Guide for Laboratory Animal Resources, National Research Council.The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense.     

Carbon dioxide sensitivity of pulmonary receptors in the frog.

Pulmonary mechano-receptors have been found in the frog lung that are sensitive to CO2 concentrations in the lungs and airways comparable to the physiological levels recorded in frogs. These results support the suggestion that a pulmonary receptor with distinct mechano- and chemosensitive properties may represent the functional precursor of the more specialized pulmonary receptor types which have evolved in birds and mammals.     

Failure of coffee to inhibit the pharmacodynamic activity of morphine in vivo

Summary High doses of caffeine-containing as well as decaffeinated instant coffee neither inhibited morphine-induced analgesia in mice nor the morphine-induced fall of blood pressure, heart rate and respiratory rate in rats. On the contrary, caffeine-containing coffee even enhanced the analgesic effects of morphine in mice. Coffee thus does not exhibit opiate-antagonizing activity in the whole organism in vivo. The very weak morphine-antagonistic efficacy of coffee powder in the myenteric plexus-longitudinal muscle preparation from the guinea pig ileum is of no practical importance.     

Failure of coffee to inhibit the pharmacodynamic activity of morphine in vivo

High doses of caffeine-containing as well as decaffeinated instant coffee neither inhibited morphine-induced analgesia in mice nor the morphine-induced fall of blood pressure, heart rate and respiratory rate in rats. On the contrary, caffeine-containing coffee even enhanced the analgesic effects of morphine in mice. Coffee thus does not exhibit opiate-antagonizing activity in the whole organism in vivo. The very weak morphine-antagonistic efficacy of coffee powder in the myenteric plexus-longitudinal muscle preparation from the guinea pig ileum is of no practical importance.     

Failure of cilia of reprogram following segmental ampullary reversal of the rabbit oviduct

Summary Cilia exhibited unidirectional and coordinated movement within microsurgically reversed segments of rabbit ampulla when examined up to 13 months after surgery. The direction of ciliary beating was opposite that of the remainder of the oviduct.This research was supported in part by a grant (HD 09339-06) from the National Institutes of Health and the Bioassay and Smooth Muscle Core Laboratories (NIH grant P30 HD10202).     

碳纳米管场致电子发射研究进展

碳纳米管（CNTs）具有独特的电子、化学、力学特性,且易制备,作为冷阴极场发射材料在平板显示领域有潜在的应用价值而引起了人们的极大兴趣。本文简单介绍了几种改善碳纳米管薄膜场致电子发射特性的实验方法研究进展,并对碳纳米管场发射显示器研究进展进行了综述。     

Carbon monoxide releasing molecules: New insights for anticoagulation strategy in sepsis

Sepsis is a common and serious medical condition caused by hemorrhage, trauma, or abdominal surgery. Despite new understanding and much progress in therapies that specifically interfere with an interesting target, sepsis remains the leading causes of death in critically ill patients. Various therapies have been studied, but the majority of these treatments fail in clinical trials. It is clear that all septic patients exhibit coagulation abnormalities. These abnormalities range from subtle to marked activation of coagulation system, and finally to fulminant DIC. Studies confirmed that carbon monoxide has important cytoprotective function and anti-inflammatory properties. Until now, the question of whether CO plays a critical role in improving the coagulation system and then decreasing mortality during sepsis has not yet been definitely answered. Attempts to confirm this strategy may lead to new directions in the study of treatment of sepsis and the development of a novel agent for this disorder. Received 13 August 2008; received after revision 29 October 2008; accepted 17 November 2008     

Failure of calcium to stimulate Na,K-ATPase in the presence of EDTA

Summary The effect of calcium on Na, K-ATPase activity of rat brain homogenates and its modification by the chelating agent EDTA has been investigated. In the absence of EDTA, free calcium (approximately 10^–6mol/l) stimulates Na,K-ATPase activity; in the presence of EDTA the same concentration of free calcium is without effect on the enzyme. In the absence of EDTA the stimulation by calcium of Na,-K-ATPase activity is enhanced by the additional presence of calmodulin but in the presence of EDTA, even when calmodulin is added to excess, calcium still fails to stimulate the enzyme. The possibility that EDTA interferes with an interaction between a calcium-calmodulin complex and Na,K-ATPase is discussed.The expert technical assistance of Mrs Paula Jarvie is gratefully acknowledged. Thanks are due also to Professor Philip Kuchel for assistance with the calculations to determine the concentrations of metal-ligand complexes in the experimental media.     

Failure of iodoacetate to protect the antigenic power of insulin from cystein inactivation

Resumen La capacitad de reacción de la insulina de bovino con un anticuerpo especifico desaparece completamente cuando, previamente, se incuba la muestra en presencia de Cisteina. Concentraciones de iodoacetato hasta 1 · 10^–2M no son capaces de proteger a la hormona contra la acción inactivadora del aminoacido.     

Failure of calcium to stimulate Na,K-ATPase in the presence of EDTA

The effect of calcium on Na,K-ATPase activity of rat brain homogenates and its modification by the chelating agent EDTA has been investigated. In the absence of EDTA, free calcium (approximately 10(-6) mol/l) stimulates Na,K-ATPase activity; in the presence of EDTA the same concentration of free calcium is without effect on the enzyme. In the absence of EDTA the stimulation by calcium of Na,K-ATPase activity is enhanced by the additional presence of calmodulin but in the presence of EDTA, even when calmodulin is added to excess, calcium still fails to stimulate the enzyme. The possibility that EDTA interferes with an interaction between a calcium-calmodulin complex and Na,K-ATPase is discussed.     

中国高新技术企业引进PE投资的失利因素分析

随着近几年中国PE投资逐渐升温,具有高增长潜力的高新技术企业备受青睐。本文分析了高新技术企业不同发展阶段PE投资的特点及投资合作的基本流程,试图从现阶段中国高新技术企业引进PE投资的角度对一些导致引资失利的因素进行深入探讨。本文主要从企业自身客观条件不足和缺乏引资策略技巧这两个方面进行了归纳分析,以期为PE投资与高科技项目的成功合作起到借鉴和促进作用。