The effect of acidic polysaccharides and prostaglandin-like substances isolated from Propionibacterium acnes on granulocyte chemotaxis.

Three acidic polysaccharide (AP) fractions and the prostaglandin-like substances (PLS) isolated from P. acnes were investigated regarding their chemotactic activities on polymorphonuclear leukocytes. Both AP's and PLS induced a significant chemotatic response, which suggests their involvement in inflammatory acne vulgaris.     

Effect of insulin on immunological phagocytosis by macrophages.

It was shown that, in physiological concentrations, insulin enhances, in vitro, the immunological phagocytosis of sensitized sheep erythrocytes by cultured mouse peritoneal macrophages. Insulin seems to stimulate macrophage phagocytosis as a cholinomimetic agonist by increasing the intracellular levels of cyclic GMP.     

Microwave measurements of the absolute values of absorption by water vapour in the atmosphere

MEASUREMENT of the absolute value of absorption by water vapour at microwave frequencies is difficult because the effect is so small. Far in the wings of the absorption lines, in the so-called 'windows' of the spectrum, it is especially difficult to achieve high accuracy in the free atmosphere. But it is in these windows that the behaviour of the absorption is important from both applied and scientific points of view. Satellite communications, remote sensing of the atmosphere, and radioastronomy, are all influenced by this behaviour. Measurements on an Earth-space path are reported here; the results indicate a nonlinear relationship between absorption and water-vapour content.     

Multiplicity of monoamine oxidase in chick brain

Summary The substrate- and inhibitor-related characteristics of monoamine oxidase (MAO) were studied on chick brain mitochondria. It was found that neither 5-hydroxytryptamine nor -phenylethylamine is the specific substrate for type A and type B MAO in chick brain.     

Global inventory of natural and anthropogenic emissions of trace metals to the atmosphere

FEW (if any) recent studies on the atmospheric cycle of trace metals have considered the flux of the metals into the atmosphere on a global scale. Information on worldwide emissions is needed to assess the transboundary movement of pollutant metals and to validate models of the global atmospheric circulation patterns. The worldwide inventories of the natural and anthropogenic sources and emissions of airborne cadmium, copper, lead, nickel and zinc are presented here. The data summarised here are taken from very detailed studies published elsehwere(1-5).     

Pyrogen fever in rabbits pretreated with p-chlorophenylalanine or 5, 6-dihydroxytryptamine.

The hyperthermic effect of a bacterial pyrogen has been studied in rabbits pretreated or not with p-chlorophenylalanine or 5, 6-dihydroxytryptamine. The results obtained indicate that a selective reduction of cerebral 5-hydroxytryptamine levels by these drugs do not significantly affect pyrogen hypertermia.     

海南岛万泉河口沉积环境演变

根据对柱样沉积物²¹⁰Pb定年及有机碳、硫和有机碳同位素含量分析, 研究万泉河口沉积环境演变. 硫和δ¹³C均自19世纪初期开始持续减少, 硫从1.92%逐渐减少到0.36%, δ¹³C从−20.63‰减少到−23.64‰. C/S比在20世纪之前一直很稳定, 处于0.47~0.80之间, 有机碳与硫呈正相关; 在此之后, C/S比急剧增加, 至表层为3.94, 硫的含量与有机碳的增加没有相关关系. 结果表明在19世纪之前万泉河口尚为开阔的海湾, 处于正常海洋环境,未形成被沙坝围封的泻湖, 海水能够直接出入. 19世纪初期开始, 随着玉带滩沙坝向北发育, 河口逐渐被围拦成泻湖型, 进入的海水量逐渐减少; 在19与20世纪之交, 水体已开始明显淡化, 发展成为今天近乎淡水的泻湖.     

Antioxidant survey to assess antagonism to redox stress using a prokaryotic and an eukaryotic system

Using a prokaryote (Escherichia coli) and a metazoa-resembling eukaryote (Ochromonas danica), we surveyed antioxidants which might overcome redox stress imposed by menadione sodium bisulphite (MD) and buthionine sulphoximine (BSO). BSO oxidant stress was evident only inO. danica; MD oxidant stress was evident in both organisms. Glutathione, its precursors, e.g. cysteine, homocysteine, and 2-oxo-4-thiazolidine carboxylic acid, and red blood cells, emerged as prime antioxidants for relieving BSO and MD oxidant stress. BSO and MD oxidant activity and antioxidant-annulling effect inO. danica were judged comparable to those found in animal cells whereas the resultsE. coli were not entirely equivalent. TheO. danica system emerged as a practical, rapid, and useful system for pinpointing oxidant stressors and antioxidants, and shows promise for studies with mammalian systems.     

数字通信系统 第三版

本书全面介绍了数字通信系统的理论和实际应用方法，并且包含了在数字信号传输中需要运用的关于设计、实现和测试的最新方法和技术。此书介绍的基本技术有：纠错码、多路复用、数字调制、数字用户线路、电缆调制、移动无线网络、城域网和光纤网络。新的工业标准有：声音／视频编码、SONET/SDH、DWDM、ATM、宽带无线网、网络同步和网络管理。每一章节后都有评述和参考文献和大量习题（无答案）。     

城市定位与城镇群建设

城市是一个国家和民族对外开放的窗口、商品国际交换的平台，它决定着整个国家和地区的竞争力。文章对廊坊市城市发展的现状和廊坊市城镇群建设战略进行了论述，希望对我国其他城市的发展有一定的参考作用。