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211.
212.
David H. Trevena 《Annals of science》2013,70(1):45-54
The famous French chemist, Marcelin Berthelot, published his first scientific paper in 1850. However, reference to this paper has been largely ignored in the various accounts of his lasting contributions to chemistry. The probable reason for this is that this paper is concerned with a method of subjecting a liquid to tension, and it is more appropriate to regard it as a paper on physics rather than on chemistry. In the work described in this largely-forgotten paper, written whilst he was still a young research student, Berthelot showed that liquids contained in his ‘Berthelot tube’ could withstand a considerable tension; and he is the first person to have observed cavitation, a phenomenon which has been studied so widely this century. The next mention in the literature of the Berthelot tube method is at the turn of the present century, after which it again seems to have been forgotten until the 1940s; since then there has been considerable progress using the Berthelot tube technique. In this paper the work described in Berthelot's original paper is discussed in some detail, and the subsequent fruitful development of the method is also traced and assessed. 相似文献
213.
214.
Ida H. Stamhuis 《Annals of science》2013,70(6):619-641
In 1807 the first life insurance society was established in The Netherlands. In the second half of the century, life insurance societies underwent considerable expansion. During the intervening period, the lines had to be laid along which this new phenomenon was to develop in the future: between 1827 and 1830, the government started discussing the nature of its responsibility in this field and the kind of policy to be developed, and in 1830, a book on the organization of life insurance societies, the calculation of life annuities and widows' fund premiums was published, written by the mathematician Rehuel Lobatto. This book played an important role in the government's discussion. Royal Decrees which prescribed government approval for the establishment of life assurance societies were promulgated in 1830, 1833 and 1840. In 1832, Lobatto became the government's scientific adviser on the assessment of the calculations performed by these societies, and in the same year, he was also appointed adviser to the first life insurance society. From 1832 until his death in 1866 he advised the company on the use of life tables for life as well as for reversionary annuities, and he calculated the premiums based on these life tables. Another decree was promulgated in 1864 prescribing exactly which life tables were to be used. Because Lobatto probably played a part in this decree, he was responsible for a very ‘conservative’ government policy, which was no longer adequate in the second half of the century. 相似文献
215.
A. E. Börjesson M. K. Lagerquist S. H. Windahl C. Ohlsson 《Cellular and molecular life sciences : CMLS》2013,70(21):4023-4037
Estrogens are important endocrine regulators of skeletal growth and maintenance in both females and males. Studies have demonstrated that the estrogen receptor (ER)-α is the main mediator of these estrogenic effects in bone. Therefore, estrogen signaling via ERα is a target both for affecting longitudinal bone growth and bone remodeling. However, treatment with estradiol (E2) leads to an increased risk of side effects such as venous thromboembolism and breast cancer. Thus, an improved understanding of the signaling pathways of ERα will be essential in order to find better bone specific treatments with minimal adverse effects for different estrogen-related bone disorders. This review summarizes the recent data regarding the intracellular signaling mechanisms, in vivo, mediated by the ERα activation functions (AFs), AF-1 and AF-2, and the effect on bone, growth plate and other estrogen responsive tissues. In addition, we review the recent cell-specific ERα-deleted mouse models lacking ERα specifically in neuronal cells or growth plate cartilage. The newly characterized signaling pathways of estrogen, described in this review, provide a better understanding of the ERα signaling pathways, which may facilitate the design of new, bone-specific treatment strategies with minimal adverse effects. 相似文献
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217.
High-speed cinematographic recordings of single tetanized muscle fibres during a quick decrease in length revealed that the shortening was mostly localized at the fibre segment nearest the released end of the fibre, indicating that the instantaneous elasticity may not originate from the elasticity of the cross-bridges. 相似文献
218.
H. modestus, a water-snake with morphological respiratory adaptation to its habitat, presents haemoglobins with a lower Bohr effect than those of L. miliaris, an aquatic snake without such respiratory adaptations. The difference in blood lactic acid content of the 2 snakes submitted to mechanical stimuli appears to be compatible with the properties of their haemoglobins. 相似文献
219.
In the rabbit jejunum, the elevation of temperature within the range of 25-37 degrees C diminished the sensitivity to noradrenaline (NA) for both the relaxation and amplitude inhibition. The relaxation by NA was mainly mediated via adrenergic beta-receptors at 25, 30 or 37 degrees C. The amplitude inhibition was mediated via alpha-receptors at 37 degrees C, and both alpha- and beta-receptors at 30 or 25 degrees C. 相似文献
220.
The male gametogenic development of the immature rat shows inhibitory effect by the exogenous infusion of ACTH (0.25 IU and 0.50 IU; i.p.). Seminiferous tubular degeneration, Leydig cell atrophy and Sertoli cell regression are very conspicuous in the dosage of 0.50 IU ACTH (i.p.). Cytometrical and histological evidence confirms that ACTH could be inhibited by FSH during male gametogenic development which leads to cellular degeneration of testes in the immature rat. 相似文献