低频波动条件下流体平面渗流模型研究

低频振动采油技术已成为一项重要的物理增产、增注措施,但其理论研究水平目前还相对滞后于现场应用.针对这一问题,运用渗流力学、波场传播的基本原理,建立了低频波动条件下地层流体的渗流模型,定量描述了地层、流体参数与振动采油压力波动之间的关系,并利用解析方法分析计算,认为低频波场主要受储层渗透率和振动频率两大因素影响.振动采油现场施工可以通过适当调整振动频率改善施工效果.     

Detection of a metastable magnetic phase in the La1.85Ba0.15CuO4−y system

We have made samples of La_1.85Ba_0.15CuO_4–y with varying heat treatments. We have measured their dc magnetization and electron paramagnetic resonance, and have examined them by electron microscopy and electron diffraction. For samples annealed only a few hours, cooling the material below 5 K causes a magnetic transition and a thermal hysteresis. These observations, taken with the EPR data, suggest a possible spin-glass or ferromagnetic phase. Annealing samples in an oxygen atmosphere appears to remove that magnetic phase. For the phase with the K₂NiF₄ structure, no superlattice spots are seen in electron diffraction at room temperature or at 77 K.     

Orally active, hydrolytically stable, semisynthetic, antimalarial trioxanes in the artemisinin family

In only three chemical operations, natural trioxane lactone artemisinin (1) was converted into a series of C-10 carbon-substituted 10-deoxoartemisinin compounds 4-9. The three steps involved lactone reduction, replacement of the anomeric lactol OH by F using diethylaminosulfur trifluoride, and finally boron trifluoride-promoted substitution of F by aryl, heteroaryl, and acetylide nucleophiles. All of these C-10 nonacetal, chemically robust, enantiomerically pure compounds 4-9 have high antimalarial potencies in vitro against Plasmodium falciparum malaria parasites, and furans 5a and 5b and pyrrole 7a are antimalarially potent also in vivo even when administered to rodents orally.     

Cation transport: an example of structural based selectivity

Through the high-resolution structure of the gramicidin A channel in lamellar phase lipids and the characterization of specific ion peptide interactions, fundamental principles for ion channel selectivity and conductance efficiency are illustrated with atomic resolution detail. Delocalized cation binding in the first turn of the helix reduces the unfavorable entropy contribution upon binding. Stepwise dehydration minimizes the energy barrier for cation entry and provides valence selectivity in this channel. Three or more water molecules in the monovalent cation binding site result in flexibility in the cation solvation environment causing weak cation size selectivity. Lack of cation induced structural modification avoids the formation of a significant energy barrier, thus permitting efficient cation transport.     

Adult psychological functioning of individuals born with craniofacial anomalies

This study represents an initial investigation into the adult psychological functioning of individuals born with craniofacial disfigurement. A total of 24 men and women born with a craniofacial anomaly completed paper and pencil measures of body image dissatisfaction, self-esteem, quality of life, and experiences of discrimination. An age- and gender-matched control group of 24 non-facially disfigured adults also completed the measures. As expected, craniofacially disfigured adults reported greater dissatisfaction with their facial appearance than did the control group. Craniofacially disfigured adults also reported significantly lower levels of self-esteem and quality of life. Dissatisfaction with facial appearance, self-esteem, and quality of life were related to self-ratings of physical attractiveness. More than one-third of craniofacially disfigured adults (38 percent) reported experiences of discrimination in employment or social settings. Among disfigured adults, psychological functioning was not related to number of surgeries, although the degree of residual facial deformity was related to increased dissatisfaction with facial appearance and greater experiences of discrimination. Results suggest that adults who were born with craniofacial disfigurement, as compared with non-facially disfigured adults, experience greater dissatisfaction with facial appearance and lower self-esteem and quality of life; however, these experiences do not seem to be universal.     

The myelotoxicity of chloramphenicol: in vitro and in vivo studies: I. In vitro effects on cells in culture

1 Chloramphenicol is used extensively in non-industrialized countries for the treatment of life-threatening infections because it is cheap and effective, despite its known hemotoxicity and linkage to fatal aplastic anaemia. It is important to define the mechanism of toxicity so that means can be devised to ameliorate the toxic effects in order to produce safer usage. 2 Chloramphenicol, at concentrations from 5 mM to 2 mM initiated apoptosis in dividing cells from a monkey kidney-derived cell line and in haematopoietic progenitor cells from human neonatal cord blood. 3 Growth of progenitor cells was suppressed at concentrations of chloramphenicol which would be considered less than therapeutic during patient treatment. 4 These effects could be ameliorated in progenitor cells by co-culture with the antioxidant mercaptoethylamine and in monkey kidney cells by co-culture with vitamin C. 5 This is the first report of apoptosis in chloramphenicol toxicity and suggests a possible link between a metabolic event i.e. the production of free radicals; a morphological effect, apoptosis; and a clinical effect, bone marrow suppression and aplastic anaemia.     

Acute upper limb ischemia resulting from cleidocranial dysostosis

A case is reported of a woman with an ischemic arm as a result of damage to the subclavian artery by the clavicular anomaly associated with cleidocranial dysostasis. Only one similar case has been reported previously.     

社会规划:中国新的职业身份?

在“十一五”规划中，中国共产党中央委员会提出了“以人为本”的新的发展观。不再是单纯追求增长率，而是提出了一些其他的考虑要素，例如“五个统筹”，其中之一就是通过加速社会全面发展实现经济与社会的统筹发展。但是在原文中，社会发展的含义却缺乏深入探讨（中国共产党中央委员会，2006：244）。