温室的演化—从暖洞子到人工生物圈

研究和控制植物的生长发育以求增加产量的办法,主要有两方面:一是通过选择和改造植物本身,如选种、育种、嫁接、杂交等手段而产生良好的品系,现已从经验的杂交遗传,深入到细胞工程和基因工程,开创了新的突破;另一方面则是通过改变环境条件,如耕耘、灌溉、施肥、保温、保湿、通风、透光等措施来控制植物的生育活动,从而增加其经济产量。现在对于改良植物的大气环境的一些方式,就数十年来我个人所见所闻的情况来谈一谈。     

抗菌药物的降阶梯疗法

抗菌药物依照药效学特征可分为浓度依赖型和时间依赖型两大类。不同类型的抗菌药物应从药效学方面的不同来制定不同的给药方案。药效学是衡量药物浓度、药理作用及毒副作用的一门学科。目前，用于指导临床用药的药效学参数包括：（1）药物浓度高于最低抑菌浓度（MIC）的时间占给药间期的百分比（T〉MIC％），受此参数制约的抗生素主要是β-内酰胺类和大环内酯类。（2）24h曲线下面积（AUC）与MIC的比率（24hAUIC），其相关抗菌药物是氨基苷类及喹诺酮类等。（3）峰浓度（Peak）与MIC的比率，其相关抗菌药物有四环素、氨基苷类及喹诺酮类。     

Research advancement in the processes and mechanisms of transporting methane by emerged herbaceous plants and hygrophytes

Methane (CH₄) is an important greenhouse gas, and is involved in atmospheric chemical reactions. Aquatic and hydric environments are important sources of atmospheric CH₄. Majority of CH₄ are transported and released to atmosphere by emerged herbaceous plants and hygrophytes in aquatic and hydric environments. In recent decades, there has been increasing attention on how plants transport CH₄. During CH₄ transportation processes, several interfaces of CH₄ exchange play important roles. First, the tips of lateral roots are primary locations (hotspots) for CH₄ entering the root systems and regulate the gross CH₄ transportation. Then, the diaphragms in the aerenchyma and the root collar impose great resistances for the overall CH₄ transportation processes. In early studies, it was controversial that whether CH₄ emission from plants to atmosphere was controlled by stomas or micropores (small cracks and holes in aboveground part of plant except the blade). Recent studies have confirmed the dominant role of micropores for CH₄ transportation and emission. The dead and damaged stems are widely considered to have positive effects on CH₄ transportation. Diffusion and convection are the two main transporting mechanisms of CH₄, with the efficiency of convection being generally higher than that of diffusion. Both biological (e.g. biomass and photosynthesis) and environmental (e.g. light, temperature and humidity) factors regulate the CH₄ transportation. Many studies have contributed to understanding the CH₄ transportation processes and mechanisms by emerged herbaceous plants and hygrophytes. However, there are still some questions needing further investigations. Issues of consideration may include the operational efficiency in the critical interfaces of CH₄ exchange, the plant parts that play a decisive role in the entire CH₄ transportation, the underlying roles of diffusion and convection on CH₄ interfaces exchanges and entire long distance transports, the combined and coupling effects and mechanisms of biotic and abiotic factors, and the similarities and differences of CH₄ transporting processes and mechanisms among plant species.     

大剂量有机磷农药中毒1例报告

1临床资料患者,女,51岁。因与家人争吵后,自服甲胺磷农药约350ml,家人发现时患者已不省人事,约40min后送我院。入院查体:体温36.5℃,脉搏50次/分,呼吸30次/分,血压16.0/10.0kPa,神志不清,两侧瞳孔等大等圆,直径约1.5mm,对光反射迟钝。两肺可闻湿性罗音,心律齐,各瓣膜区未闻及杂音。腹部平软,肝脾肋下未触及,肠鸣音亢进。血常规:Hb127g/L,WBC9.6×109/L,N:89.6%,L:10.4%。血电解质,肝、肾功能均正常,血胆碱脂酶:13活力单位。入院后立即给予洗胃、给氧、导尿,建立静脉通道,并给予解磷定静推,阿托品微量泵持续泵入,维持阿托品化,甘露醇脱水…