Non-viraemic transmission of tick-borne encephalitis virus: a mechanism for arbovirus survival in nature

The vectors of arthropod-borne viruses (arboviruses) become infected by feeding on the viraemic blood of an infected animal. This theory is based on transmission studies involving artificial infection of vertebrate hosts by syringe inoculation. To reproduce natural conditions of virus transmission, infected and uninfected vectors (ticks) of tick-borne encephalitis virus, the most important arbovirus in Europe, were allowed to feed together on uninfected wild vertebrate hosts. The greatest numbers of infected ticks were obtained from susceptible host species that had undetectable or very low levels of viraemia. The results suggest that nonviremic transmission is an important mechanism for the survival of certain arboviruses in nature.     

Simulation of Head-Disk Collisions in Magnetic Disk Drives

Head disk collision models of "coefficient-of-restitution" are widely used in the head disk inter     

新型宽量程瓦斯传感器的应用

主要阐述了载体催化元件检测瓦斯的原理及其输出特性曲线，介绍了新型宽量程瓦斯传感器采用的新技术与其在使用中所表现出的优点以及实际应用效果。     

Negative wake behind bubbles in non-newtonian liquids

GAS bubbles rising by gravity in non-newtonian elastic liquids(1-4) are different to gas bubbles in viscous newtonian fluids in at least two ways. First, the bubbles in the non-newtonian liquids often have a peculiar tip at the rear pole, and second, the terminal rise velocity versus volume curve often has a discontinuity at a certain 'critical' volume. To investigate this unusual flow situation further we have used laser-Doppler anemometry(5) to measure the liquid velocity in the wake behind air bubbles in a non-newtonian liquid. The measurements described here reveal the unexpected result that the liquid velocity behind the bubbles is in the downwards direction away from the rising bubbles (the velocities are referred to an observer at rest with respect to the liquid far from the bubbles). Thus the liquid velocity is opposite to the velocity in the usual wake behind objects moving in viscous newtonian fluids and we have called the phenomenon 'negative wake'.     

Modulation of antibody synthesis by an anti-tumour alga

Summary An unicellular alga,Chlorella pyrenoidosa, which had been reported to protect C₃H mice against sarcoma BP8, is shown, when injected in Freund's incomplete adjuvant, to modulate the antibody synthesis induced by immunization with a hapten-carrier complex.C. pyrenoidosa appeared to be able to initiate an antigenic competition between hapten and carrier determinants of the antigen molecule during antibody synthesis, and thus it could be speculated thatC. pyrenoidosa modulates the immune response at the macrophage level.Acknowledgments. This work was supported by the Secrétariat d'Etat aux Universités and by the DGRST, grant No. 77.71347.     

Electron microscopic observation of nucleosomes in ultrathin sections of heparin-treated nuclei

Summary Isolated rat liver nuclei display nucleosomes (-bodies) in common ultrathin sections after treatment of nuclei with heparin. The masking of nucleosomes in intact chromatin by some extranucleosomal component is suggested.     

In situ noradrenaline-induced stimulation of dog thyrotrophic secretion

Summary Anterior pituitary microinfusions of noradrenaline in the dog causes a significant release of TSH while adrenaline and dopamine do not.This study was supported by Grant No. S1-049 from the Consejo Nacional de Investigaciones Cientificas y Tecnológicas, Grant No. 281 from the Consejo de Desorrallo Cientifico y Humanístico, Central University of Venezuela, and Fundación José María Vargas.     

Effects of carmine and carminic acid on embryonic tissue cell cultures

Summary The biological reaction to carmine and carminic acid at cellular level on in vitro cultures was tested and significant variables were controlled. Results suggested that proliferation and metabolism of these cultures were not affected by the 2 stains.     

The secret of truffles: A steroidal pheromone?

Summary The steroid 5-androst-16-en-3-ol has a pronounced musk-like scent. It is a major constituent of the pheromone of the boar. It occurs also in axillary sweat of men but is devoid of androgenic activity. The presence of this steroid has been demonstrated in truffles (Tuber melanosporum) both by radioimmunoassay and by gas chromatography-mass spectrometry in quantities of 40–60 ng/g fresh material. This offers an explanation for the ability of pigs to detect truffles growing as deep as 1 m under ground.     

Prevention of estrogenic inhibition of adrenal 686-1686-1686-1686-2686-2686-2in rats

Summary The urinary protein _2u stimulates adrenal ⁵-3 dehydrogenase activity and prevents adrenal enlargement in estrogen-treated adult male rats.Acknowledgements. Dehydroepiandrosterone used in this study was donated by Organon(India) Ltd, Calcutta. This work received financial support from University Grants' Commission, New Delhi. The author's thanks are due to Prof. A. K. Maiti and Prof. C. Deb, Department of Physiology, Calcutta University, for their constant encouragement.