Immunomagnetic flow cytometric detection of staphylococcal enterotoxin B in raw and dry milk

A rapid and sensitive method for detection of staphylococcal enterotoxin B (SEB) in raw and dry milk samples with the use of antibody-based immunomagnetic separation (IMS) in conjunction with flow cytometry (FCM) was developed. Sheep anti-SEB immunoglobulin G (IgG) was immobilized on Dynabeads M-280. The SEB initially binds to the capturing antibody, which is bound on the magnetic beads. The rabbit anti-SEB IgG binds to the captured toxin and is further labeled with a Cy5-labeled goat anti-rabbit IgG antibody. The percentage of the beads that were fluorescent was measured by FCM. FCM was carried out for 1 min, and the data obtained were expressed as histograms for particle size (forward light scatter) and histograms for fluorescence intensity. A peak corresponding to the magnetic beads was clearly distinguished from a peak derived from contaminating particles in the sample solution. In the absence of SEB, about 10% of the beads emitted fluorescence. The percentage of fluorescent beads and the fluorescence intensity increased with increasing SEB concentrations. For this IMS-FCM assay, the lower limits of detection for SEB were estimated to be 0.01 and 0.25 ng/ml for buffer and milk samples, respectively.     

Studies on analysis of terpene resin in imported chewing gums

We have developed an analytical method for terpene resins in chewing gum. The fraction including terpene resins was prepared by means of hexane extraction and two silica gel column chromatography treatments (hexane and ethyl acetate) from chewing gum. The terpene resin fraction was analyzed with LC/MS and IR. The terpene resins are mixtures of polymeric pinene and/or limonene, which have a monomer molecular weight of 136. The MS spectrum of the terpene resin peak on the LC/MS total ion chromatogram showed protonated molecular ion (M + H)+ peaks at intervals of m/z 136, characteristic of a complex mixture of polyterpenes. IR spectroscopy is a suitable technique to identify the terpene resin type, ie., pinene or limonene. When the method was applied to imported chewing gum sold in Japan, terpene resins were clearly detected.     

Ag-28Cu钎焊TA2/BT20接头组织分析

采用 Ag-28Cu 钎料对 TA8 纯钛和 BT20 钛合金的管板组合构件进行真空钎焊连接试验,分析了不同钎焊温度及保温时间对接头界面结构的影响.结果表明,接头界面结构为 BT20/钛基固溶体/Ti2Cu 化合物/银基固溶体+TiCu 化合物/Ti2Cu 化合物/钛基固溶体/TA2;随着钎焊温度的升高,银基固溶体和 TiCu 化合物逐渐消失,Ⅰ区逐渐出现较明显的树枝状生长的组织,分析为 Ti2Cu 化合物;随着连接时间的延长,Ti2Cu 化合物逐渐增加,且靠近母材的钛基固溶体层增宽,Ⅱ区最终演变成一个 Ti2Cu 反应层.

Abstract：

The vacuum brazing of TA2/BT20 titanium alloy was carried out with Ag-28Cu brazing filler metal, and the effects of brazing temperature and holding time on interface structure of the joints were diseussed. The experimental results showed that the interface structure consisted of BT20/Ti (s,s)/Ti2Cu/Ag (s,s) +TiCu/Ti2Cu/Ti (s,s)/TA2. The Ag (s,s) and TiCu compound decreased gradually with the increasing of brazing temperature and holding time, and then Ti2 Cu compound increased corresponding.And the Ti (s,s) layer gradually became thick.     

用体硅微加工工艺实现的微纳电械系统

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Thermophysical properties of (U,Y)O2

We prepared polycrystalline pellets of (U,Y)O₂, containing YO_1.5 up to 11 mol.%. We performed indentation tests on the pellets, and evaluated the Young’s modulus and hardness. We measured the heat capacity and the thermal diffusivity, and evaluated the thermal conductivity. We succeeded in evaluating the effect of Y content on the thermophysical properties of (U,Y)O₂. We revealed that the Young’s modulus, hardness, and thermal conductivity of (U,Y)O₂ decreased with increasing the Y content.     

二维高分辨率反演技术在苏里格气田的应用

二维常规地震反演的分辨率与地震分辨率较为接近,难以识别5m左右的储层。本文利用二维地震与三维地震的关系,首次将二维地震转化为伪三维地震,然后利用三维地震的地质统计学反演算法,对二维地震数据进行了高分辨率的地质统计学反演,从而有效提高了二维反演的纵向分辨率,可满足实际生产对二维地震储层预测的纵向分辨率的要求。同时,结合叠前道集AVO弹性波阻抗反演及高分辨率二维地震储层预测,描述薄有效储层的平面分布特征,实现利用二维地震数据预测薄有效储层的目的。     

Polymerization of ethylene and propylene initiated by milled alumina powder

Generation of free radicals (mechano-radicals) by the milling of alumina powder at 77 K was demonstrated by ESR. After milling of alumina in the presence of ethylene (simultaneous milling) at 77 K, polyethylene-propagating radicals instead of the alumina mechano-radicals were detected by ESR. Also the contact of ethylene with the milled alumina converted alumina mechano-radicals into polyethylene propagating radicals at a temperature above the melting point of ethylene. The products extracted by hot toluene from the simultaneous milling were identified by IR to be polyethylene, and their molecular weights were roughly 10,000. The residues after the extraction were bonded with the alumina. Polypropylene was also produced by a similar method of milling of alumina in the presence of propylene. The obtained polyproylene was atactic, and its molecular weight was about 400.     

Sentence alignment using P-NNT and GMM

Parallel corpora have become an essential resource for work in multilingual natural language processing. However, sentence aligned parallel corpora are more efficient than non-aligned parallel corpora for cross-language information retrieval and machine translation applications. In this paper, we present two new approaches to align English–Arabic sentences in bilingual parallel corpora based on probabilistic neural network (P-NNT) and Gaussian mixture model (GMM) classifiers. A feature vector is extracted from the text pair under consideration. This vector contains text features such as length, punctuation score, and cognate score values. A set of manually prepared training data was assigned to train the probabilistic neural network and Gaussian mixture model. Another set of data was used for testing. Using the probabilistic neural network and Gaussian mixture model approaches, we could achieve error reduction of 27% and 50%, respectively, over the length based approach when applied on a set of parallel English–Arabic documents. In addition, the results of (P-NNT) and (GMM) outperform the results of the combined model which exploits length, punctuation and cognates in a dynamic framework. The GMM approach outperforms Melamed and Moore’s approaches too. Moreover these new approaches are valid for any languages pair and are quite flexible since the feature vector may contain more, less or different features, such as a lexical matching feature and Hanzi characters in Japanese–Chinese texts, than the ones used in the current research.