Influence of cyclic nucleotides on protein synthesis in vascular smooth muscle

Summary The incorporation of leucice-¹⁴C into protein in bovine mesenteric arteries was augmented by cyclic GMP (10^–3 M) and decreased by cyclic AMP (10^–3 M). There was no effect of 5 AMP (10^–3 M). The phosphodiesterase inhibiting drugs theophylline (10^–3 M) and papaverine (5×10^–5 g/ml) both decreased the leucine-¹⁴C incorporation.We are indebted to Mrs.Lena Burlin for hear assistance. Finacial support has been provided by the Swedish State Medical Research Council (No. 04X-101X-4498).     

Ecdysone 20-hydroxylase from the midgut of the tobacco hornworm (Manduca sexta L.)

Summary An ecdysone 20-hydroxylase enzyme system that converts -ecdysone to 20-hydroxyecdysone was prepared from the midgut of the tobacco hornworm prepupa. This partially purified enzyme is NADPH dependent and is localized in the mitochondrial fraction of the midgut tissue.     

Effect of air ionization on blood serotonin in vitro

Summary The effect of negative and positive air ionisation on siliconized blood serotonin was studied in vitro. The experiments showed that within 10 min positive ionisation increased serotonin levels in total blood (+40%), plasma (+90%), erythrocytes (+50%) and thrombocytes (+200%). On the other hand, negative ionization (10 min) lowered the serotonin content of total blood (–30%), plasma (–42.5%), erythrocytes (–41.7%) and thrombocytes (–72.3%), thus confirming the Krueger Effect in vitro.This research was generously supported by a grant from the Joint Research Fund of the Hebrew University and Hadassah, and Dr. and Mrs.Leonard Appleby of Palmbeach, Florida.Acknowledgment: Our thanks are due to Mr.B. Shalita, Mrs.Zippora Adar and Mrs.Olga Fradkin for devoted technical assistance.     

嗜热乳酸杆菌T-1发酵特性的研究

对产L-乳酸的一株细菌T-1进行了营养缺陷型的初步鉴定，并对其发酵特性进行了研究?初步鉴定出蛋白胨中的某些物质是它的生长因子。培养基中加入蛋白胨后，在同样时间下比不加蛋白胨时菌体量明显增长；蛋白胨含量为15g／L时，发酵L-乳酸产量达到85．0g／L，比不加蛋白胨时的产量提高了48％；转化率为81．0％，比不加蛋白胨时的转化率提高了25％，从其发酵特性试验得出了T-1的最适发酵条件。发酵液中L乳酸的纯度为99．396。     

世界优秀男子110 m栏运动员成绩变化分析

采用文献资料调查、数理统计等科研方法, 对1997年世界田径锦标赛男子110 m栏前 7 名运动员的成绩进行相关分析, 揭示当今男子110 m栏全程速度变化的规律和特点, 并对近 4 年来世界优秀男子 110 m栏运动员与我国男子110 m栏运动员的成绩进行对比分析, 希望能对我国男子110 m栏的训练提供一些新的参考和启示.     

^210Pbex depth distribution in soil and calibration models for assessment of soil erosion rates from ^210Pbex measurements

Throughout the past decade, the potential for using nuclear weapon-produced 137Cs ( half-life 30.2 a) fallout to quantify soil erosion rates on both cultivated and uncul- tivated lands for medium-term timescales (≈ 40 a) has been successfully demonstrated in a wide range of envi- ronments in different regions of the world[1—6]. Because in difficulties of distinguishing Chernobyl-derived compo- nent from total 137Cs input in many parts of Europe, and in measuring low activity samples of…     

Progress in the study of tectophysicochemistry

Tectophysicochemistry is a research area that deals with the interrelations between physical and chemical changes of crustal materials caused by tectonism. A given tectonic force may be resolved into two parts: homogeneous stress and differential stress. Homogeneous stress refers to isotopic pressure, which is superimposed on the original pressure and affects the equilibrium of various chemical reactions. It is also a factor that influences petrogenesis,metallogenesis and metamorphism. Differential stress is commonly produced when external forces act on a given solid body. It may cause deformation of crustal materials and generate various kinds of structural features. Tectophysicochemistry pays special attention to pressure, temperature and other physicochemical conditions produced or induced by tectonism and studies the influences of additional tectonic parameters on various chemical equilibria, so it gradually develops into an independent area of science.     

Structural and Chemical Diversity of TI-Based Cuprate Superconductors

The first TI一based euprate supereonduetor,TI一Ba-Cu一(),was diseovered by 2.2.Sheng and A.M.Hermann仁1〕. TI beeomes supereondueting at 2.38 K.NumerousTI eompounds and alloys are supereondueting.TIMo6Ses has the highest transition temperature of1 2.2 K among all non一euprate Tl eontaining alloyand eompound supereonduetors.Before thediseovery of the euprate supereonduetors,some TIeontaining oxide supereonduetors were found,among whieh TI。.3W()3 has the highest transitiontemPerature,2.14 K. Sinee the diseovery of TI euPratesuPereonduetors,two distinet families have beenidentified.Soon after the diseovery of TI一Ba一Cu-(),supereonduetivity was eonfirmed in TI一Ba一Ca-Cu一()samples.The ehemieal eompositions anderystal struetures of those eompounds were workedout as T12BaZCu()6,T12BaZCaCuZ()。,andT12BaZCaZCu3OI。[2〕.This 15 the first family of TIeuPrate supereonduetors,whieh features two TIatoms in eaeh ehemieal formula.     

大学预科化学课程教学探讨

本针对大学预科班学生的特点，从大学预科化学课程的基本目的和要求出发，讨论大学预科化学课程教学中应注意的问题．     

Land vehicle positioning using GPS and dead reckoning

To ensure reliable land vehicle positioning, the Global Positioning System (GPS) is one of the best techniques commonly used in present-day positioning systems. However, GPS signals are not available if line of sight with the satellites is lost. In this respect, the addition of the Dead Reckoning (DR) method to complement the GPS unit would enhance the reliability of land vehicle positioning system. For implementing the DR method, the magnetic sensor and accelerometer are used for obtaining heading and velocity or distance information. Calibration of two sensors' dynamic model and DR algorithm are also introduced in this paper. The test result utilizing the GPS and DR methods is analyzed in this paper. It utilize spositioning information from GPS receiver when GPSsignal is available, otherwise DR is started to compensate GPS outage with the GPS output as the original point. The results showed that the error in east and north produced by the DR algorithm for a short time interval can be limitedwithin an acceptable range.