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.     

Beta-adrenergic receptors in rat myocardium: Direct detection by a new fluorescent beta-blocker

Summary A new fluorescent -blocker, 9-amino-acridin propranolol (9-AAP), was administered i.v. to rats. Multiple fluorescent 9-AAP binding sites were observed on cardiac muscle cells in frozen sections. Intensity and density of cardiac 9-AAP fluorescence were markedly reduced following pretreatment with (±)- and (–)-propranolol but not with (+)-propranolol. Our findings suggest that 9-AAP may label -adrenergic receptor sites in rat myocardium.D. A. is supported by a fellowship from the Lady Davis Fellowship Trust and by a Research Grant from the Bat-Sheva de Rothschild Fund for The Advancement of Science and Technology. The technical assistance ofA. Itzhak is gratefully acknowledged.     

Does an inhibitor of mitochondrial adenylate kinase also affect oxidative phosphorylation?

Summary Adenylate kinase activity of intact mitochondria is strongly inhibited by Ap₅A, i.e.p ¹,p ⁵-Di (adenosine-5-) pentaphosphate, whereas oxidative phosphorylation is not affected. Therefore, Ap₅A is a useful tool to distinguish between oxidative and non oxidative ATP generating reactions.Acknowledgment. The generous support of Prof. Dr.Walther Lamprecht is gratefully acknowledged. J. L. thanks the Stipendienfonds des Verbandes der Chemische Industrie for a scholarship.     

Organization of myosin molecules in the muscle thick filament

Summary Tryptic treatment of muscle thick filaments reveals the underlying backbones of aggregatedl-meromyosin as a coli of 3 secondary filaments (helical repeat 130 nm) each in turn a coli of a 3 finer ones.     

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。     

基于自适应直线拟合的角点检测

角点检测是计算机视觉的一个基本问题，进行角点检测的关键是估算曲率。笔者给出了一种新的基于参考点的前后曲线方向估计的曲率计算方法。我们以离散点远离直线垂直距离误差最小为目标进行直线拟合，同时根据误差大小来自适应的选择拟合窗口的大小。很好地解决了角点曲率计算时拟合窗口大小和计算精度间的矛盾，实验证明，该方法抗干扰性好，且运算量不大，对于存在明显转折点的曲线角点有很好的检测和定位能力。     

D类音频功率放大器控制方式综述

D类放大器虽然具有很高的效率，但由于功率晶体管的开关工作方式，D类放大器引入的失真通常大于线性放大器，这也是目前D类放大器在音频放大领域并未得到广泛应用的主要原因。D类放大器的控制方式是影响其性能的关键因素之一，研究适合的控制方法以改善D类放大器的保真度，是近年来电力电子技术和音频功放放大领域研究的热点。文中对几种比较新颖的D类音频功放放大器控制方式进行了分析比较。