988 resultados para 173-1065
Resumo:
该文以C57BL/6J鼠分2组进行实验。实验组45鼠,对照组20鼠,与同品系雄鼠交配后,在3日龄胚期,通过腹部手术对实验组雌鼠每侧子宫腔内注入未稀释的H-Y抗血清与豚鼠补体(二者以1:2混合)3μl。抗血清是由C57BL/6L雌鼠用同品系雄鼠的脾细胞以2.5×10~(7)个/只的剂量,每周免疫一次,共免疫7次后制备。对照组的处理操作与实验组相同,但每侧子宫腔内仅注入补体3μl,未注入抗体。实验组中有42只产仔247只(每窝平均6只),雌雄比为2.7(180/67)雌性占73%;对照组20只均产仔共163只(每窝平均8只),雌雄比为0.92(78/85),雌性仔鼠占48%。
Resumo:
该实验采用7只成年雄性猕猴, 经双侧阴囊上方切口暴露输精管, 由近附睾端向远侧注射高分子聚合物HFMC, 剂量分别为30mg/侧(1只),60mg/侧(3只), 100mg/侧(3只), 分别于术后22.5及3.5年处死动物, 取附睾组织进行光镜及电镜观察. 结果表明: 注射不同剂量 HFMC 2.5年后, 动物附晕头、体、尾各部光镜观察所见主要改变为上皮细胞局灶性轻度水样变性, 少许上皮细胞脱落, 个别管腔扩张, 局部间质少量炎细胞浸润. 3.5年后取材光镜观察附睾组织无明显异常. 不同时间取材进行电镜观察所见超微结构变化主要为上皮细胞内线粒体肿胀, 部分线粒体及内织网呈空泡改变, 附睾管腔内精子均有一定程度损伤。
Resumo:
This response does not only include greening the campus but also transforming curricula and teaching and learning. This book explains why this is necessary and--crucially--how to do it.
Resumo:
Laser micro machining is fast gaining popularity as a method of fabricating micro scale structures. Lasers have been utilised for micro structuring of metals, ceramics and glass composites and with advances in material science, new materials are being developed for micro/nano products used in medical, optical, and chemical industries. Due to its favourable strength to weight ratio and extreme resistance to chemical attack, glassy carbon is a new material that offers many unique properties for micro devices. The laser machining of SIGRADUR® G grade glassy carbon was characterised using a 1065 nm wavelength Ytterbium doped pulsed fiber laser. The laser system has a selection of 25 preset waveforms with optimised peak powers for different pulsing frequencies. The optics provide spot diameter of 40 μm at the focus. The effect of fluence, transverse overlap and pulsing frequency (as waveform) on glassy carbon was investigated. Depth of removal and surface roughness were measured as machining quality indicators. The damage threshold fluence was determined to be 0.29 J/cm2 using a pulsing frequency of 250 kHz and a pulse width of 18 ns (waveform 3). Ablation rates of 17 < V < 300 μm3/pulse were observed within a fluence range of 0.98 < F < 2.98 J/cm2. For the same fluence variation, 0.6 μm to 6.8 μm deep trenches were machined. Trench widths varied from 29 μm at lower fluence to 47 μm at the higher fluence. Square pockets, 1 mm wide, were machined to understand the surface machining or milling. The depth of removal using both waveform 3 and 5 showed positive correlation with fluence, with waveform 5 causing more removal than waveform 3 for the same fluence. Machined depths varied from less than 1 μm to nearly 40 μm. For transverse overlap variation using waveform 3, the best surface finish with Rz = 1.1 μm was obtained for fluence 0.792 J/cm2 for transverse overlap of 1 μm, 6 μm, and 9 μm at machined depths of 22.9 μm, 6.6 μm, and 4.6 μm respectively. For fluence of 1.426 J/cm2, the best surface finish with Rz = 1.2 μm was obtained for transverse overlap of 6 μm, and 9 μm at machined depths of 12.46 μm, and 8.6 μm respectively. The experimental data was compiled as machining charts and utilised for fabricating a micro-embossing glassy carbon master toolsets as a capability demonstration.