利用P因子不精确剪切获得Tis11基因敲除果蝇

Tis11是哺乳动物基因TTP在果蝇中的同源物,其基因位于果蝇X染色体11B9区.它含有两个保守的顺式Cys-X8-Cys-X5-Cys-X3-His(CCCH)锌指结构.它与mRNA的稳定性有关.为了进一步从动物水平研究Tis11的生物学功能,作者利用P因子不精确剪切的特性来获得Tis11基因敲除果蝇.以P因子插入果蝇19949为起始材料,经过一系列杂交后,挑取了700株P因子被切除的果蝇.通过PCR筛选和鉴定,从这700株果蝇中获得一株果蝇279,它的Tis11基因的第2个外显子中包括翻译起始位点的区域被删除

比较经颅超声造影和数字减影血管造影对大脑中动脉狭窄的诊断价值研究 Diagnostic Value of Transcranial Contrast-enhanced Ultrasound and Digital Subtraction Angiography for Middle Cerebral Artery Stenosis

【摘要】 目的 比较经颅超声造影（transcranial contrast-enhanced ultrasound，t-CEUS）和DSA在大脑中动脉（middle cerebral artery，MCA）狭窄性疾病中的诊断价值。 方法 收集2017年12月-2019年4月疑似MCA狭窄或闭塞的患者197例，记录其225条狭窄或闭塞的大脑中动脉的t-CEUS和DSA检查结果。根据MCA狭窄程度分为轻度狭窄（30%～50%），中度狭窄（50%～69%），重度狭窄（70%～99%）和闭塞（100%），以DSA为金标准，分析t-CEUS对轻、中和重度MCA狭窄的诊断价值。 结果 197例疑似MCA狭窄闭塞患者中，男132例，女65例，年龄43～72岁，平均（58.4±4.6）岁。经DSA确诊的狭窄和闭塞的225条MCA中，轻度狭窄16条，中度狭窄70条，重度狭窄121条，闭塞18条。t-CEUS诊断狭窄和闭塞的共224条MCA，其中，轻度狭窄18条，中度狭窄76条，重度狭窄112条，闭塞18条。t-CEUS和DSA诊断MCA狭窄和闭塞高度吻合（Kappa=0.91）。t-CEUS诊断轻度MCA狭窄的敏感度、特异度和准确度分别为80%、80%和91%；诊断中度MCA狭窄的敏感度、特异度和准确度分别为83%、93%和97%；诊断重度MCA狭窄的敏感度、特异度和准确度分别为83%、96%和96%。 结论 t-CEUS能够清楚地显示轻、中、重度MCA狭窄和闭塞，适用于MCA狭窄和闭塞类疾病患者的确诊，尤其是适用于不适合DSA检查的疑似MCA狭窄和闭塞患者。 【Abstract】 Objective To investigate the diagnostic value of transcranial contrast-enhanced ultrasound (t-CEUS) and digital subtraction angiography (DSA) for middle cerebral artery (MCA) stenosis or occlusion. Methods A total of 197 patients with suspected MCA stenosis or occlusion from December 2017 to April 2019 were enrolled. A total of 225 stenostic or occluded MCAs were diagnosed by t-CEUS and DSA, according to the degree of MCA stenosis, the MCAs were divided into four groups: mild (30%-50%), moderate (50%-69%), severe (70%-99%) and occlusion (100%). Taking DSA diagnosis as the golden standard, the specificity, sensitivity, and accuracy of t-CEUS diagnosis were analyzed by comparing the results of ultrasound imaging. Results Of all the 197 patients, 132 male and 65 female, with the average age (58.4+4.6) years and the range 43 to 72 years. Of 225 MCAs diagnosed by DSA, 16 MCAs were mild, 70 were moderate, 121 were severe, and 18 were occluded. Of 224 MCAs diagnosed by t-CEUS, 18 were mild, 76 were moderate, 112 were severe, and 18 were occluded. The diagnosis of MCA stenosis/occlusion using t-CEUS and DSA had a high consistency (Kappa=0.91). The sensitivity, specificity and accuracy of t-CEUS for the diagnosis of mild MCAs were 80%, 80%, and 91%, respectively; the sensitivity, specificity and accuracy of t-CEUS for the diagnosis of moderate MCAs were 83%, 93%, and 97%, respectively; the sensitivity, specificity and accuracy of t-CEUS for the diagnosis of severe MCA were 83%, 96%, and 96%, respectively. Conclusions t-CEUS can clearly show mild, moderate and severe stenosis and occlusion in MCAs, and it is suitable for the diagnosis of patients with MCA stenosis and occlusion, especially for the patients with suspected MCA stenosis and who are not suitable for DSA

苯在光滑铂电极上的电化学还原行为的共焦显微拉曼研究

本文利用共焦显微拉曼仪系统研究了苯在光滑铂电极上的电化学还原。研究结果表明:苯在电化学体系中可直接还原为不溶于水的环己烷液滴,附在电极表面构成第三相,随着电位的正移,表面液滴中苯和环己烷的相对含量会发生变化

Confocal microprobe Raman spectroscopic study of electrochemical reduction of benzene on a platinum electrode

The electrochemical reduction of benzene on a smooth Pt electrode has been studied by confocal microprobe Raman spectrosocopy. The results show that benzene can be reduced directly to cyclohexane, which is insoluble in water, adhered onto the electrode surface to form the third phase. After the drops have been formed on the electrode surface, the relative concentration of benzene to cyclohexane in the drops will rather increase with prolonging the time at a certain electrode potential, although it decreases with the negative shift of the electrode potential at first