Acute effects of carbon monoxide and cyanide on hepatic mitochondrial function

The effects of carbon monoxide and cyanide on the hepatic redox state and energy charge were investigated. Rats were used for the experiment under pentobarbital anesthesia. Immediately after laparotomy, a rat was placed in an animal chamber made of a transparent plastic box and exposed to a test gas for 3 min. Every test gas was produced in a gas chamber connected to the animal chamber with a flexible tube. HCN was produced from NaCN and H2SO4. In the CO inhalation experiment, various amounts of CO were introduced into the gas chamber. Immediately after an exposure, about 2 g liver was frozen in situ with a precooled clamp. Oozed blood from the wound surface was sampled. Concentrations of ATP, ADP, AMP, acetoacetate, and beta-hydroxybutyrate in hepatic mitochondria were determined, and the redox state and the energy charge were calculated. For cyanide as well as CO, significant negative correlations were found between the concentration in the blood and the redox state. The same held true for the energy charge. The redox state showed a slight increase at low concentrations of both gases; however, thereafter it began to decrease sharply with increases in concentrations. When concentrations of the toxicant in the blood reached certain levels, a kind of turning point, beyond which the redox state does not decrease any more, was observed. It was about 40% for HbCO and about 2.0 micrograms/ml for cyanide, and the points seemed to be related to the concentrations, beyond which cells are irreversibly damaged. On the other hand, the energy charge did not change at low concentrations. With an increase in toxicant concentrations, the energy charge decreased drastically. The rate of decrease in the energy charge became higher when blood concentrations exceeded certain levels. It was about 40% for HbCO and 2.0 micrograms/ml for cyanide. The presence of low levels of blood cyanide did not affect the relationship between the energy charge and the HbCO concentration.     

Implementing Change in an Urban School District: A Case Study of the Reorganization of the Little Rock School District

In July 2005, the Little Rock, Arkansas, school district implemented a new policy to reorganize its management structure in order to create a more efficient bureaucracy. Using Richard Matland’s ambiguity‐conflict model of policy implementation, the authors examine the implementation of this school reorganization policy. Interviews and surveys were conducted with the superintendent and his executive assistants, school principals, teachers, and staff. In line with Matland’s model, the findings suggest that successful implementation is directly related to the policy characteristics of ambiguity and conflict. However, the authors point to the importance of recognizing particular characteristics for different groups of stakeholders within the policy implementation process. Discrepancies among groups of policy actors in the degree of policy ambiguity and policy conflict lead to strikingly different implementation strategies.     

当代中国的定位与战略理念

2008北京奥运的完美落幕进一步突出了中国改革开放以来的发展成就,标志着中国的国力、国势、国运进入新的上升轨道,中国与世界的关系再度成为国际热点话题。中国的发展、崛起将引起国际格局、国际体系发生什么样的变化?在变化中的世界,尤其是在中国发展本身就构成国际变局重要组成部分、国际上"中国威胁论"及"中国责任论"等此起彼伏的情况下,中国又面临着什么样的新任务、需要确立怎样的国家大战略、做出何种新的战略选择?要不要居安思危,继续坚持韬光养晦?对这些问题,不仅精英层在严肃思考,普通民众也极为关切。鉴此,《现代国际关系》杂志社2008年8月31日以"‘奥运后时代’中国与世界的关系"为题举办研讨会,邀请京津两地20多位相关领域专家、学者就上述问题展开深入讨论。现将会议主要观点辑录如下,以飨读者。     

Blood group frequencies of the population of Trinidad and Tobago, West Indies.

The results of grouping tests performed on blood samples collected over a five-year period at the Trinidad and Tobago Forensic Science Centre are presented. The samples were tested using the ABO, PGM, EAP and GLO blood group systems. Phenotypic frequencies and allele frequencies for each system were calculated for the two major ethnic groups of the population, the African and East Indian. Matching probabilities, which can be used in the interpretation of physical evidence in forensic cases, were also calculated.     

Heterogeneity of market power: firm-level evidence

Economic Change and Restructuring - Recent work in macroeconomics argues that firm market power dramatically increased since the 1980s in the world. The evolution of product markups has important...