排序方式： 共有133条查询结果，搜索用时 15 毫秒
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不同分子量壳聚糖的制备及其抑菌性能的研究 总被引：1，自引：0，他引：1
本实验在超声波条件下用过氧化氢降解壳聚糖制备低分子量壳聚糖,研究了过氧化氢用量、温度、时间、pH值等对壳聚糖溶液粘均分子量的影响,并对降解产物进行红外光谱分析。探讨了降解产物对大肠杆菌、白色念珠菌、枯草芽孢杆菌的抑菌性能。实验结果表明,超声波协同过氧化氢氧化降解壳聚糖的较适宜条件为:1%(w/v)的壳聚糖溶液,加入3%(v/v)的过氧化氢溶液,pH值约为5.0,数控超声清洗仪工作功率为80%,频率为40kHz,温度设定为(50.0±2.0)℃,随着降解时间不同可得到不同粘均分子量的壳聚糖。降解得到的产物对三种细菌均有抑制生长的效果,其中粘均分子量为5.0×104的壳聚糖的抑菌能力最强,且对大肠杆菌的抑制作用最强。 相似文献
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Health concerns during the Covid-19 pandemic required the adaptation of a lecture-laboratory course in ultrasound imaging for graduate students from an in-person to a live, remote learning format. The adaptation of in-person lectures to live, remote delivery was achieved by using videoconferencing. The adaptation of in-person laboratory sessions to live, remote instruction was achieved in the first half of the course by providing a hand-held ultrasound instrument to each student who performed self-scanning at their remote locations, while the instructor provided live instruction using videoconferencing. In the second half of the course, the students transitioned to using cart-based, hospital-type instruments and self-scanning in the ultrasound laboratory on campus. The aim of this study was to measure the success of this adaptation to the course by comparing assessment scores of students in the live, remote course with assessment scores of students in the in-person course offered in the previous year. There were no statistically significant differences in the assessment scores of students in the two courses. The adaptation of a course in ultrasound imaging from an in-person to a live, remote learning format during the Covid-19 pandemic described here suggests that contrary to the prevailing view, ultrasound imaging can be taught to students without in-person instruction. The adapted course can serve as a model for teaching ultrasound where instructors and learners are physically separated by constraints other than health concerns during a pandemic. 相似文献
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Joseph M. Gonzales Andrew J. Galpin Melissa M. Montgomery 《Journal of sports sciences》2013,31(19):2184-2190
ABSTRACTWe examined the association between footfall pattern and characteristics of lower limb muscle function and compared lower limb muscle function between forefoot and rearfoot runners. Fifteen rearfoot and 16 forefoot runners were evaluated using ultrasonography of the gastrocnemii and tibialis anterior while strike index and heel strike angle quantified footfall pattern. Higher strike index was associated with lower medial gastrocnemius echo intensity (p = 0.05), lower lateral gastrocnemius echo intensity (p = 0.04), smaller tibialis anterior pennation angle (p = 0.05), and longer lateral gastrocnemius fascicle length (p = 0.04). Larger heel strike angle was associated with smaller medial gastrocnemius cross-sectional area (p = 0.04), shorter lateral gastrocnemius fascicle length (p < 0.01), and lower plantar flexion moment (p < 0.01). Larger plantar flexion moment was associated with lesser medial gastrocnemius echo intensity (p = 0.04), lesser lateral gastrocnemius echo intensity (p = 0.03), and greater lateral gastrocnemius fascicle length (p = 0.02). A smaller plantar flexion moment, larger heel strike angle, lower tibialis anterior echo intensity, larger tibialis anterior pennation angle, and smaller lateral gastrocnemius pennation angle were observed in rearfoot compared to forefoot runners (p < 0.05). Lower limb muscle architecture is associated with footfall pattern and ankle mechanics during running.Abbreviation: EMG: electromyographic; MG: medial gastrocnemius; LG: lateral gastrocnemius; TA: tibialis anterior; EI: echo intensity; CSA: cross-sectional area; PA: pennation angle; FL: fascicle length; FT: fat thickness 相似文献
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利用三价铁盐在超声波条件下水解生成透明氧化铁黄颜料,探讨了超声水解的影响因素,并对产品进行了沉降时间、耐酸、耐碱及耐热性和TEM等表征分析。 相似文献
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采用文献资料法、测试法、数理统计法对黑龙江省青年男子短道速滑运动员体成分及跟骨超声参数的特点及相关性进行研究,为其科学运动训练提供有关体成分及骨代谢方面的资料。结果显示：短道速滑运动员体重、体脂率和瘦体重与普通大学生相比差异显著,与体育类大学生相比差异不显著;短道速滑运动员跟骨超声参数T值显著低于普通大学生和体育类大学生;Pearson相关分析和多元线性回归分析得出身高、体重、身体质量指数、瘦体重与T值呈显著相关,瘦体重是决定跟骨超声参数的主要因素。得出长期高强度的运动训练对黑龙江省青年男子短道速滑运动员跟骨超声参数产生了不良的影响,维持和增加瘦体重及制定适宜的运动训练方案,对促进黑龙江省青年男子短道速滑运动员骨健康,提高运动员的运动能力,防治运动性损伤是有益的。 相似文献
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激光脉冲激发的超声脉冲波形的理论研究 总被引：1，自引：0，他引：1
在激光热弹产生超声的研究中，对于产生超声的激光脉冲波形，大都是采取简化处理了的矩形脉冲或三角形脉冲，这样的处理虽然在计算上较易得出结论，但它与真实的高斯激光脉冲有较大的差别。为此笔者采用更接受于实际激光脉冲波形的梯形脉冲模型，应用热传导方程和Navier-stokes方程对半无限大介质中所激发的超声脉冲特性进行了计算研究，结果得出了比矩形脉冲更具有普遍性的结果，也与实验结果相符。 相似文献
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丁久香 《襄樊职业技术学院学报》2011,10(3):33-34
目的探讨彩色多普勒超声诊断宫外孕的特征性依据,提高宫外孕诊断的准确性。方法对临床怀疑异位妊娠患者行多途径（经阴道或腹部）彩色多普勒超声探查子宫附件区域,并与血人绒毛膜促性腺激素（HCG）检查结果比较,确诊宫外孕。结果 100例疑似宫外孕患者的超声检查中,5例因附件区未见异常包块未能确定。另95例均发现附件区包块,其中包块内实质性部分可检测到滋养血流信号57例,频谱为低阻力型;伴有不同程度的盆腹腔积液54例,双侧卵巢可同时显示85例。结论对疑似早期宫外孕的患者进行二维经阴经腹彩超检查,测量包块处滋养动脉血流频谱存在,同时测定血HCG阳性,可以早期诊断宫外孕。 相似文献
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Rachel R. Walden Nakia J. Woodward Richard L. Wallace 《Medical reference services quarterly》2019,38(1):22-30
Rising collection costs sometimes necessitate tough decisions regarding cancellation of popular products. In 2015–2016, the East Tennessee State University Medical Library subscribed to UpToDate and DynaMed Plus, both clinical point-of-care products, with the understanding that one product would be canceled at the fiscal year end. The librarian team undertook a year-long community engagement campaign to inform library users about the pending product cancellation decision. Ultimately, DynaMed Plus was selected and UpToDate was cancelled. The campaign generated user engagement with the decision making, along with perceived benefits including increased awareness of the library's budget constraints, increased discussion of scholarly publishing, and greater faculty/student knowledge of evaluating evidence-based products. 相似文献