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排序方式: 共有341条查询结果,搜索用时 15 毫秒
331.
Ganglionic transmission: electrophysiology and pharmacology 总被引:1,自引:0,他引:1
N J Dun 《Federation proceedings》1980,39(12):2982-2989
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W Wouters R De Coster N Goeminne D Beerens J van Dun 《Journal of steroid biochemistry》1988,30(1-6):387-389
The aromatase inhibitory properties of the antifungal ketoconazole were compared with those of aminoglutethimide. In rat granulosa cells ketoconazole and aminoglutethimide showed IC50 values for aromatase inhibition of 2 X 10(-6) and 6 X 10(-7) M respectively. In the rat, in vivo, ketoconazole was 5 times less potent than aminoglutethimide. In young women, 400 mg of ketoconazole only marginally lowered plasma levels of estradiol-17 beta. It is concluded that ketoconazole is not a compound of choice for clinical use as an aromatase inhibitor. 相似文献
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Effects of VIP, PHM and substance P on blood vessels and secretory elements of the human submandibular gland 总被引:2,自引:0,他引:2
O Larsson M Dunér-Engstr?m J M Lundberg B B Fredholm A Angg?rd 《Regulatory peptides》1986,13(3-4):319-326
The effects of the neuropeptides VIP, PHM and substance P (SP) on vascular smooth muscle tone, K+ secretion from exocrine elements and tissue content of cyclic AMP (cAMP) in the human submandibular gland were studied in vitro. All three peptides caused relaxation of noradrenaline contracted human submandibular arteries at nM concentrations. SP was slightly more active than VIP and PHM which had a similar potency as vasodilators. Only carbachol but not VIP, PHM or SP stimulated K+ secretion from exocrine elements of the human submandibular gland. Principally similar in vitro effects on K+ secretion were obtained on the cat submandibular gland, but in the rat not only carbachol but also SP stimulated K+ secretion. VIP and PHM increased cAMP production of exocrine elements in the human submandibular gland in nM concentrations. VIP was about 5-fold more potent than PHM with regards to cAMP production. In conclusion, VIP, PHM and SP relaxed human submandibular arteries in vitro. Both VIP and PHM stimulated cAMP production in glandular tissue but none of the three peptides induced K+ secretion from human submandibular gland tissue. This suggests that, in contrast to the situation in the rat, SP does not cause watery salivation in man, while VIP and PHM may modulate protein e.g. amylase content of the saliva. 相似文献
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Wanshang Xia Dezhi Han Dun Li Zhongdai Wu Bing Han Junxiang Wang 《The Annals of applied biology》2023,182(2):144-158
Pests are the main threats to crop growth, and the precision classification of pests is conducive to formulating effective prevention and governance strategies. In response to the problems of low efficiency and inadaptability to the large-scale environment of existing pest classification methods, this paper proposes a new pest classification method based on a convolutional neural network (CNN) and an improved Vision Transformer model. First, the MMAlNet is designed to extract the characteristics of the identification object from different scales and finer granularity. Then, a classification model called DenseNet Vision Transformer (DNVT) combining a CNN and an improved vision transformer model is proposed. The proposed DNVT captures both long distance dependencies and local characteristic modelling capabilities, which can effectively improve pest classification accuracy. Finally, the ensemble learning algorithm is used to learn MMAlNet and DNVT classification forecasts for soft voting, further enhancing the classification accuracy of pests. The simulation experiment results on the D0 and IP102 datasets show that the proposed method attained a maximum classification of 99.89 and 74.20%, respectively, which is better than other state-of-the-art methods and has a high practical application value. 相似文献
338.
Cadmium (Cd) in coals has attracted much attention due to its potential toxicity. In the present study, we reviewed up-to-date information on the abundance, distribution, and modes of occurrence of Cd in Chinese coals, as well as its environmental effects. With the 3110 sets of data rearranged, the arithmetic and weighted mean of Cd concentration in Chinese coals were calculated. Using coal reserves in individual province and coal-forming ages as weighting factors, the estimated average Cd abundances in Chinese coals are 0.25 mg/kg and 0.42 mg/kg, respectively. Variations in Cd coal abundances in different geographical locations, coal-forming ages, and coal ranks are taken into account. The Cd abundances in northern Chinese coals are significantly lower than those in the southern Chinese coals. Sulfides, especially sphalerite, are the most common Cd carriers in coals. As a semi-volatile element, Cd can be partially transformed into a volatilized form during highly thermal process, which could enrich surrounding fly ash. The combination of electrostatic precipitator and flue gas desulphurization is proved to be a better effective method for reducing emissions of Cd. Heavy loadings of Cd in environmental compartments due to anthropogenic activities have posed a great challenge to atmosphere–land–ocean systems. 相似文献
339.
Masoudi Abolfazl Koprowski John lad Bhattarai Upendra Raj Wang Dun 《Applied microbiology and biotechnology》2018,102(3):1483-1499
Applied Microbiology and Biotechnology - Entomopathogenic fungi are considered to be a safe microbiological pesticide alternative to chemical control. Efforts are underway to understand precisely... 相似文献
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