卡式微柱凝胶法在猴血型鉴定中的应用

下载PDF阅读器灵长类动物的ABO血型抗原都表达在组织器官内,而不是在红细胞上,这给灵长类动物血型的鉴定带来很大的困难.为找到更加简捷、准确鉴定灵长类动物类人ABO血型的方法,采用近年来临床上广泛应用的卡式微柱凝胶正、反定型法对34只猕猴和16只食蟹猴的血型进行了鉴定,并与肾组织免疫组化法的检测结果进行比较.结果显示:卡式微柱凝胶正定型法的检测结果中无一例为阳性结果;血浆中的纤维蛋白原和人-猴种属间非特异性抗体都会对卡式微柱凝胶反定型法的部分检测结果产生干扰;采用经正常人O型红细胞吸附处理后的清亮血清,卡式微柱凝胶反定型法的检测结果明确,与免疫组化法判定结果一致.由此得出:卡式微柱凝胶反定型法可以用于灵长类动物血型的鉴定,其主要干扰因素为血浆内的纤维蛋白原和人-猴种属间非特异性抗体,在采用清亮血清及经正常人O型红细胞吸附处理后能消除其干扰.

核酸四碱基体的量子化学计算方法比较

对9种四碱基体进行了6种半经验方法和HF／sT0—3G的计算，结果表明PM3方法对四 碱基体体系的计算比较适宜，其结果与从头算结果接近，而且大大缩短了计算时问。计算 还说明，四碱基体极有可能是通过碱基对形成．由稳定能的顺序看，除已报道的3种四碱 基体G4、G·c·G·c和u4外，一种新的G·c·G·c四碱基体也有稳定存在的可能。

The decay of Saffman and batchelor turbulence subject to rotation, stratification or an imposed magnetic field

We consider unforced, statistically-axisymmetric turbulence evolving in the presence of a background rotation, an imposed stratification, or a uniform magnetic field. We focus on two canonical cases: Saffman turbulence, in which E(κ → 0) ∼ κ 2, and Batchelor turbulence, in which E(κ → 0) ∼ κ 4. It has recently been shown that, provided the large scales evolve in a self-similar manner, then u ⊥ 2ℓ ⊥ 2ℓ // = constant in Saffman turbulence and u ⊥ 2ℓ ⊥ 4ℓ // = constant in Batchelor turbulence (Davidson, 2009, 2010). Here the subscripts ⊥ and // indicate directions perpendicular and parallel to the axis of symmetry, and ℓ ⊥, ℓ //, and u ⊥ are suitably defined integral scales. These constraints on the integral scales allow us to make simple, testable predictions for the temporal evolution of ℓ ⊥, ℓ //, and u ⊥ in rotating, stratified and MHD turbulence.

Experimental study of homogenisation in grid turbulence

Turbulence statistics have been measured immediately downstream of a regular grid made of round rods with rod spacing M. 2D-2C PIV was used to analyse a measurement area of 14M x 4M in the down and cross-stream directions respectively. The relevant Reynolds number span the range Re M = U ∞M/ν = 5 500 - 16 500. The Reynolds shear stresses recorded on two parallel measurement planes differently located relative to the grid exhibit significant discrepancies over the first 5M, but have completely homogenised in the cross-stream direction by x/M = 7. The downstream evolution of the two-point velocity correlation functions shows a progressive loss of coherence and a clear trend towards the expected isotropic behavior. The same conclusions apply to measurements taken in the wake of another regular grid made of square rods. Changes in the vortex shedding pattern from the grid were observed at the lowest Reynolds number, with two of the four rod wakes captured shedding in phase with each other but in anti-phase with a third one. The impact of this early flow coherence on the turbulence statistics did not persist due to the homogenisation process.