池蝶蚌精子形态及其活力

池蝶蚌精子具有子弹形头部及细长均匀鞭毛尾,属鞭毛型。全长为254.91±20.03μm;头部子弹形,长为32.33±2.15μm,宽为16.60±3.29μm;鞭毛细长均匀,长为216.67±19.73μm。为了更好的计算池蝶蚌精子的存活率,本研究采用曙红Y染色的方法,观察了精子在生理盐水、池塘水和蒸馏水中的存活时间及运动方式。结果显示,精子在生理盐水中的存活时间最长,可达6h;其次是蒸馏水,约为4.5h;最短存活时间是在池塘水中,约为4.0h。池蝶蚌精子的主要运动方式有快速直线游动、弧线运动和原地转动3种方式。快速直线游动的精子活力最高,其次是弧线运动,精子活力降低后进行原地转动。研究的结果对池蝶蚌家系的建立起重要作用。     

Anti-Metatype Antibody Screening,Sandwich Immunoassay Development,and Structural Insights for β-Lactams Based on Penicillin Binding Protein

Theoretically, sandwich immunoassay is more sensitive and has a wider working range than that of competitive format. However, it has been thought that small molecules cannot be detected by the sandwich format due to their limited size. In the present study, we proposed a novel strategy for achieving sandwich immunoassay of β-lactams with low molecular weights. Firstly, five β-lactam antibiotics were selected to bind with penicillin binding protein (PBP)2x* to form complexes. Then, monoclonal and polyclonal antibodies against PBP2x*-β-lactams complexes were produced by animal immunization. Subsequently, the optimal pairing antibodies were utilized to establish sandwich immunoassay for detection of 18 PBP2x*-β-lactam complexes. Among them, ceftriaxone could be detected at as low as 1.65 ng/mL with working range of 1–1000 ng/mL in milk. To reveal the detection mechanism, computational chemistry and molecular recognition study were carried out. The results showed that β-lactams with a large size and complex structures maybe conducive to induce conformational changes of PBP2x*, and then exhibit greater possibility of being detected by sandwich immunoassay after combination with PBP2x*. This study provides insights for subsequent investigations of anti-metatype antibody screening and sandwich immunoassay establishment for small-molecule detection.     

随机缺陷对蜂窝结构动态行为影响的有限元分析

通过对胞壁随机移除的蜂窝结构动态变形过程的有限元模拟,分析了随机缺陷对蜂窝结构变形模式的影响,得到蜂窝结构在两个加载方向上的变形模式图及不同模式间转换的临界速度. 对含缺陷蜂窝结构平台应力的研究发现,当变形模式为过渡模式或动态模式时结构平台应力与冲击速度的平方成线性关系. 相同密度下,低缺陷蜂窝结构的平台应力在由过渡模式向动态模式转变的临界速度附近高于规则蜂窝结构,较高的随机缺陷则使蜂窝结构的平台应力在由准静态模式向过渡模式转变的临界速度附近显著下降.关键词:多孔材料,蜂窝,缺陷,平台应力,有限元分析      

近壁湍流统计性质研究

采用大涡模拟方法,模拟了槽道湍流,得到了不同雷诺数下槽道湍流的结果. 在此基础上,研究了平均速度、雷诺应力、脉动动能和脉动速度均方根的分布;讨论了平均速度的壁面律问题;给出了雷诺应力、脉动动能和脉动速度均方根随雷诺数的变化规律,其中雷诺应力、脉动动能给出了定量公式.      

日光强度涨落自关联消湍流成像

从关联成像理论出发,提出了日光场在实际大气湍流环境中强度点对点自关联成像理论,并进行了实验验证,分析了太阳光强度二阶自关联成像和强度点对点二阶自关联成像的区别.研究结果表明,太阳光场的点对点四阶自关联,即强度的二阶点对点自关联,可实现消大气湍流成像.为验证理论有效性,利用外场实验进行了验证,获得优于17 km距离的消湍流成像结果.理论和实验均表明,太阳光强度涨落的点对点自关联可实现消大气湍流成像.相比于相机直接成像,本文成像方法消除了大气湍流影响,同时该方案极大提升了关联成像技术的实用性,可直接用于远距离消大气湍流的高质量成像,增加图像识别率.理论表明,任何成像过程中波前受相位扰动影响的波段,如红外、紫外等,均可利用本文方法消除影响,成果具有较大实用价值.     

Electrochemical Determination of Vitamin B12 Based on Cu2+‐Involved Fenton‐like Reaction

Poly(thionine) (PTH) film was generated on the electrochemically activated glassy carbon electrode (GCE(ea)) by using the two‐step cyclic voltammetric scan. Scanning electron microscopy, infrared spectral analysis and electrochemical measurement were employed to characterize the modified electrode surface. Hydroxyl radicals, which were produced by the Fenton‐like reaction, could induce the effective oxidization of PTH under near‐neutral condition and cause the notable enhancement of the cathodic peak current (I_pc) during the potential cycling process. Due to the binding of copper ions with the ligands liberated from V_B12 and the inferior catalytic ability of Co²⁺ for the generation of hydroxyl radicals, the addition of V_B12 into the Cu²⁺?H₂O₂ system inhibited the oxidization of PTH and resulted in the decrease of the I_pc value. The cathodic peak current change was linear with the logarithm of the V_B12 concentration in the range of 10 nmol L^?1–100 μmol L^?1 with a detection limit of 2 nmol L^?1 under optimal conditions. The developed sensor displayed excellent analytical performance including high sensitivity, good selectivity, acceptable reproducibility and satisfactory stability. The V_B12 content in the injection sample was measured and the recovery values were in the range of 92.0 %–102 %.     

NO2和HSO反应的机理及动力学研究

本文采用CCSD(T)/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ方法构建了NO2 + HSO反应的单、三重态势能面,并对主通道速率常数进行了计算。研究结果表明,该反应在单[R1(HN(O)O + 1SO)、R2(cis-HONO + 1SO)和R3 (trans-HONO + 1SO)]、三重态[R6(HN(O)O + 3SO)、R7(cis-HONO + 3SO)和R8(trans-HONO + 3SO)]均存在3条抽氢反应通道,在单[R4(NO + HS(O)O)和R5(H + SO2 + NO)]、三重态[R9(HS(O)O + NO)和R10(H + SO2 + NO)]均存在两条抽氧通道,其中单重态抽氢通道R2 (cis-HONO + 1SO)是NO2 + HSO反应主通道。利用传统过渡态理论(TST)并结合Wigner校正,计算了上述10条通道在200 ~ 1000 K温度范围内的速率常数。计算结果表明,NO2 + HSO反应主通道在298 K时的速率常数(7.78×10-13cm3?molecule-1?s-1)与实验值(9.6×10-12 cm3?molecule-1?s-1)相吻合。此外,水分子影响主通道R2(cis-HONO + 1SO)经历了NO2 + H2O…HSO和 NO2 + H2O…HSO(HSO + NO2…H2O)两条反应通道,且两条通道的能垒分别比R2升高了49.97和20.43 kcal?mol-1,说明在实际大气环境中水分子对NO2 + HSO反应几乎没有影响。     

鲁棒匹配点颤振预测的高效μ方法

基于含有参数不确定性的时域鲁棒颤振μ预测工具, 首先提出一种不确定多项式建模方法, 该方法通过线性分式变换(LFT)最终可以得到较低阶次不确定描述; 然后, 考虑到参数不确定问题中实μ(realμ)的计算复杂性, 又提出一种包含二分法的鲁棒颤振预测技术, 该方法是基于在一定飞行范围内飞行速度与气弹系统稳定性间的简单关系, 它能够避免鲁棒匹配点颤振预测中包含的高阶速度摄动块, 从而大大提高颤振预测的计算效率. 最后数值验证和对比表明了该方法的高效性.      

Rhodium nanoparticles stabilized by ionic copolymers in ionic liquids: long lifetime nanocluster catalysts for benzene hydrogenation

Novel ionic liquid-soluble ionic copolymers containing imidazolium ionic liquidlike units have been synthesized. Rhodium nanoparticles stabilized by the ionic copolymer in ionic liquids have been successfully obtained. The nanoparticles showed unprecedented lifetime and activity in arene hydrogenation under forcing conditions (a temperature of 75 degrees C and a hydrogen pressure of 40 bar) with a total turnover (TTO) of 20 000 (in five total recycles of 4000 TTOs each) and a turnover frequency of 250 h-1, demonstrating that the combination of ionic liquids with ionic liquidlike stabilizers is a pathway towards highly stable and active nanoparticle catalysts.     

The new method for introduction of an allyl group into the angular position of 2-(TBS-oxymethyl)-2,3,4,6,7,8-hexahydro-1-benzopyran-5-one and its application to chiral Wieland-Miescher type compound synthesis

The stereoselective introduction of an allyl group into the angular position of 2-(TBS-oxymethyl)-2,3,4,6,7,8-hexahydro-1-benzopyran-5-one was accomplished using Birch reduction and an enolate trapping reaction. It was determined that the allyl group was introduced via an unexpected conformation-flipped from the initially formed one. Two diastereomeric Wieland-Miescher type compounds, having the allyl group at the angular position, were synthesized as optically pure forms.