毛发中海洛因代谢物的释放与分析方法研究

通过对海洛因吸食者毛发和空白添加标准品毛发的碱消解、酸消解、甲醇超声提取、甲醇-5 mol/L HCl超声提取、甲醇-三氟乙酸超声提取5种毛发中毒品及其代谢物的释放方法考察,确立了甲醇超声提取-液液萃取-气相色谱/质谱-选择离子检测的方法.本方法可最大程度地抑制海洛因的中间代谢物6-单乙酰吗啡的水解,其水解率仅为2.63%,极大地提高了海洛因滥用的毛发证据作用.利用本方法对添加6-单乙酰吗啡的毛发进行萃取和检测,6-单乙酰吗啡的回收率为52.6%,相对标准偏差RSD为4.6% ;对添加不同浓度的吗啡、可待因、6-单乙酰吗啡3种毒品的毛发进行萃取和检测,其线性良好(r＞0.99),相对标准偏差均小于15%.此外,考察了甲醇消解的影响因素,吸毒者毛发中的毒品释放效果随毛发的细碎程度和超声时间延长而提高.     

基于显微共聚焦拉曼光谱技术快速检测3种梭菌中肉毒梭菌

提出了一种基于显微共聚焦拉曼光谱技术的肉毒梭菌快速鉴别方法.利用共聚焦显微拉曼光谱技术(CRM)采集了肉毒梭菌、艰难梭菌和产气荚膜梭菌的拉曼光谱,比较了3种梭菌的平均拉曼光谱,采用基线校正、标准正态变换、Savitzky-Golay 5点平滑和最大最小值归一化预处理后,借助主成分分析(PCA)降维并提取特征变量,对样本...     

2-(5-溴-2吡啶偶氮)-5-二乙氨基酚显现人体皮肤表面镀锌工具遗留印迹

研究2-(5-溴-2吡啶偶氮)-5-二乙氨基酚(5-Br-PADAP)试剂显现镀锌工具遗留印迹的方法。 考察接触时间、时间间隔、试剂浓度、是否洗手等因素对印迹强度及分辨率的影响,并对该方法的可靠性进行验证。 实验结果表明,试剂浓度1 g/L、接触时间10 s以上,间隔时间不超过4 h条件下,均能显出较好的印迹。 该方法可以灵敏地显现镀锌工具遗留印迹,对非铁金属工具遗留印迹检测进行了很好地补充。     

Facile preparation of hydrophilic glutathione modified magnetic nanomaterials for specific enrichment of glycopeptides

Investigations of glycosylated proteins or peptides and their related biological pathways provide new possibilities for illuminating the physiological and pathological mechanisms of glycosylation modification. However, open-ended and in-depth analysis of glycoproteomics is usually subjected to the low-abundance of glycopeptides, heterogeneous glycans, and a variety of interference molecules. In order to alleviate the influence of these obstacles, effective preconcentration of glycopeptides are indispensable. Here, we employed a hydrophilic interaction liquid chromatography (HILIC)-based method to universally capture glycopeptides. Glutathione modified magnetic nanoparticles (Fe₃O₄@Au-GSH) were synthesized through a simple process and exploited to enrich glycopeptides from complex samples. The prepared materials showed excellent ability to trap glycopeptides from standard glycoproteins digests, low detection limit (10 fmol/μL), and good selectivity (HRP:BSA = 1:100). These results indicated that glutathione-based magnetic nanoparticles synthesized in this work had great potential for glycopeptides enrichment.     

基于背景自适应预测的星点提取算法

在分析星图中的星点目标和背景特性的基础上,提出了一种基于背景自适应预测的星点提取算法。为准确预测背景并兼顾算法的速度,只在背景边缘处使用区域最大值背景预测法,其余部分直接使用固定权值进行预测。分割残差星图,提取各星点的目标区域,阈值采用自适应的取值方式。利用质心算法求取各星点目标的精确位置。实验结果表明,基于背景自适应预测的星点提取算法性能优于现有的星点提取算法,是一种有效的星点提取算法,可以降低大量由于强边缘而引起的虚警,能够更准确地预测背景。     

Rheology of a sonofluidized granular packing

We report experimental measurements on the rheology of a dry granular material under a weak level of vibration generated by sound injection. First, we measure the drag force exerted on a wire moving in the bulk. We show that when the driving vibration energy is increased, the effective rheology changes drastically: going from a non-linear dynamical friction behavior --weakly increasing with the velocity-- up to a linear force-velocity regime. We present a simple heuristic model to account for the vanishing of the stress dynamical threshold at a finite vibration intensity and the onset of a linear force-velocity behavior. Second, we measure the drag force on spherical intruders when the dragging velocity, the vibration energy, and the diameters are varied. We evidence a so-called “geometrical hardening" effect for smaller-size intruders and a logarithmic hardening effect for the velocity dependence. We show that this last effect is only weakly dependent on the vibration intensity.     

Raman lasing near 650 nm from pure water microdroplets on a superhydrophobic surface

We demonstrate Raman lasing near 650 nm in pure water microdroplets located on a superhydrophobic surface. In the experiments, stationary, pure water microdroplets were prepared on a superhydrophobic surface and excited by a pulsed, frequency-doubled Nd:YAG laser at 532 nm. Intense laser emission was observed at frequencies corresponding to the whispering gallery mode resonances of the water microdroplets near 650 nm where Raman resonances due to OH-stretching bonds of water are located. On–off behavior was observed during lasing and the average temporal inter-burst separation was determined from the time-dependent intensity traces. Our results can find applications in the development of novel organic light emitters for short-haul communication systems, and in the spectroscopic characterization of water microdroplets on a surface.     

基于GSI的锦屏地下厂房岩体参数研究

工程开挖卸荷后岩体参数研究一直是工程界关注的焦点,是稳定性评价的基础性工作。本文以锦屏地下厂房开挖工程为背景,通过对上下游边墙不同桩号段开挖揭露的岩体进行工程地质岩组划分,进行了开挖后岩体质量评价并对其进行分类,通过在GSI(Geological Strength Index)评价体系中引入Jv(节理数/m³),使评价体系相对合理化,经回归分析,对不同风化程度的岩体进行了力学参数求解,发现内聚力及内摩擦角的计算值与建议值吻合较好。     

大型复杂松散堆积体形成机制的内外动力耦合作用初 探

在我国西部山区广泛发育和分布第四纪大型复杂松散堆积体,这是一套介于土、岩之间的过渡类型的地质体;其成因复杂,主要包括残坡积物、崩滑堆积体、冲洪积物、冰碛物和冰水沉积物等两种或多种组合混杂堆积,明显区别于东部平原区的单一成因类型。本文通过资料对比分析,对大型复杂松散堆积体的一般特征、主要类型和区域分布规律进行了系统总结,最后从"耦合"的角度来探讨其成因机制,并提出河谷型松散堆积体的内外动力耦合概念模型,研究认为大型复杂松散堆积体属于典型的内外动力耦合作用产生的多期次、成因复杂的复合地质体。     

Parametric excitation of two internally resonant oscillators

The response of two-degree-of-freedom systems with quadratic non-linearities to a principal parametric resonance in the presence of two-to-one internal resonances is investigated. The method of multiple scales is used to construct a first-order uniform expansion yielding four first-order non-linear ordinary differential (averaged) equations governing the modulation of the amplitudes and the phases of the two modes. These equations are used to determine steady state responses and their stability. When the higher mode is excited by a principal parametric resonance, the non-trivial steady state value of its amplitude is a constant that is independent of the excitation amplitude, whereas the amplitude of the lower mode, which is indirectly excited through the internal resonance, increases with the amplitude of the excitation. However, in addition to Poincaré-type bifurcations, this response exhibits a Hopf bifurcation leading to amplitude- and phase-modulated motions. When the lower mode is excited by a principal parametric resonance, the averaged equations exhibit both Poincaré and Hopf bifurcations. In some intervals of the parameters, the periodic solutions of the averaged equations, in the latter case, experience period-doubling bifurcations, leading to chaos.