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排序方式: 共有362条查询结果,搜索用时 15 毫秒
341.
Cecilia Beatriz Peña-Valdivia Maria Luisa Ortega-Delgado 《Plant foods for human nutrition (Dordrecht, Netherlands)》1986,36(1):27-34
Four varieties of common bean were examined, but there were no significant differences among them. Crude protein content (46.7% and 49.0%) was the main constituent in embryonic axes. The average values of ash, crude fiber and ether extract were 4.2%, 3.7% and 3.0% respectively. Starch was approximately three times more abundant (7.5%) than cellulose (2.7%). Hemicellulose B values were lower (5.5%) than hemicellulose A (9.2%). The mean value of the pectic substances in embryonic axes was 12.3%. The free ethanol-soluble sugars ranged from 2.9% to 4.9%. Verbascose, stachyose, raffinose, sucrose, and galactose were identified and quantified in embryonic axes. Seed coat flour contained cellulose (30.6%), ether extract (0.4%), ash (2.8%), and protein (5.4%). Free ribose, mannose, arabinose, and galactose were present in seed coats in amounts ranging from 0.009% to 0.031%. 相似文献
342.
Responses of circulating arginine vasotocin, isotocin, and melatonin to osmotic and disturbance stress in rainbow trout (Oncorhynchus mykiss) 总被引:1,自引:0,他引:1
E. Kulczykowska 《Fish physiology and biochemistry》2001,24(3):201-206
In teleost fish exposed to stressors AVT has been implicated in activation of the hypothalamo-pituitary-interrenal axis. Mel has been shown to counteract several behavioural and endocrine consequences of stress in mammals. These studies were undertaken to investigate the effects of either disturbance or osmotic stress, applied either separately or simultaneously, on plasma AVT, IT and melatonin in rainbow trout (Oncorhynchus mykiss). Hormones were determined in plasma by high-performance liquid chromatography preceded by solid-phase extraction. The results showed that both forms of stress caused significant increase in plasma AVT concentration, although more pronounced elevation was observed in physically disturbed fish. Conversely, neither osmotic nor disturbance stress affected plasma IT concentration. The apparent difference in response to stress by the two close related neurohypophysial nonapeptides suggests independent mechanisms controlling their synthesis and/or release and supports the idea that only AVT plays a role in physiological response to stress. Plasma Mel level was depressed in fish subjected to disturbance stress and to both stresses applied simultaneously, an effect possibly associated with the elevation of plasma AVT concentration. Results are discussed in relation to physiological interactions between hormones. 相似文献
343.
猪的肠道微生物与宿主营养代谢 总被引:3,自引:0,他引:3
肠道中栖息着数量庞大复杂多样的微生物菌群,肠道微生物在宿主健康中发挥着重要作用,既影响着饲料消化、营养物质吸收和能量供应,又调控着宿主正常生理功能及疾病的发生与发展.动物胃肠道不仅是消化器官,还是感应器官,肠道对营养物质的感应可以通过脑肠轴调节机体生理活动.肠道微生物还能代谢蛋白质产生宿主细胞不能合成的肽类物质,并通过小肠上皮的肽类转运系统影响机体代谢,因此可能存在微生物-肠道-大脑轴.肠道微生物还可以与机体形成宿主-微生物代谢轴,对动物机体营养物质代谢和免疫稳态起重要作用.饲粮对宿主代谢的改变,常伴随有肠道微生物区系的变化,肠道微生物的代谢可能通过微生物-肠道-大脑轴以及宿主-微生物代谢轴调节宿主很多生理过程,进而影响机体整体代谢.本文概述了猪肠道微生物区系与宿主肠道营养物质代谢的关系,以加深关于肠道微生物对机体代谢贡献的认识. 相似文献
344.
Qin Shuren Wang Jiachen Hu Xinyi Jiang Guongcheng 《保鲜与加工》1990,(1):1-12
The paper introduces a new method-QL system suggested for the first time by the author for measuring dynamic accuracy of gear cutting machine drivetrain. The system has many uses. It suits not only the measurement of mid-size machine tool but also the measurement of very slow speed, large ratio, large-size machine drivetrain 相似文献
345.
AIM: To observe the dynamic changes of IL-23/IL-17 inflammatory axis in psoriasis-like lesions of mice induced by imiquimod (IMQ).METHODS: BALB/c female mice were randomly divided into control group and IMQ group. The morphological changes of lesional skin in mice were evaluated according to the psoriasis area and severity index (PASI) and HE staining. cytokine antibody chips were used to determine the cytokine changes in serum and lesions. The mRNA and protein expression of cytokines were analyzed by cytometric bead array, real-time PCR and Western blotting. Moreover, the changes of cellular constituents in the peripheral blood and splenic cells of mice were detected by flow cytometry.RESULTS: Typical psoriasis-like skin lesions, such as red scaly skin plaques, caused by topical IMQ showed a parabolic dynamic change. There was a dynamic increase in proinflammatory cytokines of the IL-23/IL-17 axis in IMQ-treated skin. IMQ application resulted in elevated expression of cytokines related with IL-23/IL-17 inflammatory axis,Th1-type cytokines,Th2-type cytokines and Treg-type cytokines at day 4. IMQ-treated BALB/c mice showed an increased pericentage of dentric cells in peripheral blood and spleen compared with control animals. Percentages of Th17 and Treg in IMQ-treated mice were increased by 3~4 times and twice as compared with control mice, respectively.CONCLUSION: The skin lesions, histopathological features and cytokine changes in mice induced by IMQ are similar to human psoriasis, which are suitable for investigating the pathogenesis of psoriasis as a psoriasis-like model. IL-23/IL-17 axis is involved in the formation of psoriasis-like skin lesions in mice induced by IMQ and presents a dynamic change. Besides, Th1 cell-mediated inflammatory response is also activated in the formation of lesional skin, accompanied by the increase expression of Th2 and Treg cytokines in a feedback mechanism. 相似文献
346.
347.
实度对直叶片垂直轴风力机风轮气动性能的影响分析 总被引:1,自引:0,他引:1
实度是直叶片垂直轴风力机设计的关键参数,对风力机气动性能起主导作用.分析并建立了垂直轴风力机局部流场下的力学模型,研究实度与气动性能的关系;对风力机进行了数值模拟,分析了叶片的动态力学特性,并重点研究风轮半径、弦长及叶片数量对风能利用率的影响;进行了样机实验验证了数值模拟的精度与可靠性.研究发现:实度增加,风力机在低尖速比下的启动特性得到改善,但产生高风能利用率的有效尖速比范围变小;样机实度为0.628时,2叶片和4叶片风轮的输出功率相当,但4叶片风轮的输出功率比2叶片风轮更稳定;实度参数对风能利用率贡献不同,弦长变化可提高风能利用率的峰值,而叶片数量的增加会降低风能利用率的峰值. 相似文献
348.
内生假单胞菌诱导棉花抗蚜性的研究 总被引:2,自引:1,他引:1
研究采用胚轴切断扦插法诱导棉株产生抗虫性。该方法是在棉花2片真叶期,将其根茎在下胚轴处切断,接种假单胞菌,扦插使其生根。通过该机械损伤及菌处理,诱导棉株产生系统抗性。实验设菌诱导扦插株和无菌诱导扦插株两项处理,以自然生长棉株作对照。诱导棉株扦插时,接种假单胞菌(PseudomonagladioliD-2251)的抗利福平突变菌株。生根后取其根、茎、叶组织,检测其体内接种菌菌量,结果发现诱导菌能够在棉株体内定殖,其浓度高低顺序为:根>茎>叶;诱导后,棉株体内单宁含量在各生长期均有不同程度提高,菌诱导株和无菌诱导株的变幅分别为30.78%~289.99%和3.88%~139.69%。除盛花期外,各生长期酚含量也有所提高,菌诱导株和无菌诱导株的变幅分别为2.60%~36.22%和1.32%~26.16%;温室条件下,对诱导株上的自然感蚜状况进行了调查;5叶期,菌诱导和无菌诱导棉株的百株蚜量分别降低74.95%和43.51%,有蚜株率分别降低67.84%和54.98%;7叶期,百株蚜量分别降低35.98%和17.21%,有蚜株率分别降低32.24%和17.21%。 相似文献
349.
田兴运 《中国农村水利水电》2010,(2):114-116
针对钢梁的支承加劲肋和中间横向加劲肋承受支座反力或固定集中荷载的腹板平面外稳定性,将加劲肋简化为两端不同约束条件下两端轴力不等的轴心压杆。采用瑞丽-里兹法分析了两端固定、两端铰接、上端铰接下端固定或上端固定下端铰接等4种情况下两端轴力不等的轴心压杆的稳定,给出了计算长度系数的计算公式。用所推导的公式计算的计算长度系数值均小于《钢结构设计规范》(GB50017-2003)所给计算长度系数1(两端铰接除外),说明《钢结构设计规范》(GB50017-2003)对支承加劲肋和中间横向加劲肋的稳定验算是偏于保守的。并为有限元分析结果提供了理论依据,也弥补了现有研究资料的缺憾。 相似文献
350.
针对悬臂式多级离心泵易出现陀螺效应,造成转子失稳与泵机组振动等问题,根据理论公式计算所得的密封流体激励力、泵腔流体激振力和附加质量代入有限元模型进行仿真计算,得到悬臂式多级离心泵的轴心轨迹图,并分别与未加载3种激励力、只加载密封流体激励力与添加密封和泵腔流体激振力的计算结果进行对比分析,最后利用Bently 408型便携式数据采集系统对轴心轨迹进行试验,对仿真进行验证。研究结果表明:加载叶轮口环密封力能够提高转子系统的稳定性,并能有效降低径向位移幅值;泵腔中流体激振力增加了转子系统的交叉刚度,导致振幅增加;相比于密封流体激励力和泵腔流体作用力,流体附加质量对悬臂式转子系统的瞬态响应的影响更为显著。 相似文献