Reactivity of hydroxybenzoic acids in the hydrogen-isotope exchange reaction.

The hydrogen-isotope exchange reaction (T-for-H exchange reaction) between tritiated water vapor (HTO vapor) and 3-hydroxy-4-methoxybenzoic acid (and it's analog; 4-hydroxy-3-methoxybenzoic acid) were observed at 50 and 70 degrees C in a gas-solid system to reveal the reactivity of a functional group in an aromatic compound having two substituents in the aromatic ring. Further, it was shown that (a) the reactivity of the compounds used in this work follows the Hammett's rule, and (b) the reactivity of trisubstituted aromatic compound could be analyzed by applying the additive property of the Hammett's rule even if the compound contains a substituent at the ortho-position.     

Radiofrequency ablation of the connections between two atriums in dogs

Atrialpreferentialpathways,consistedofatrialcellsarrangedinlongitudinaldirectionandlocatedinspecialregions,havebeenrecognizedtoplayanimportantroleinsinusimpulsepropagationbetweentwoatriuminphysiologicalcondition[1].Recentstudiesshowedthattheinteratrialconduitalsocontributedtotheinitiationandmaintenanceofsomekindsofatrialarrhythmiabytravelingectopicimpulsesandreentriesbetweentwoatriums[2].Soitwassuggestedthattheblockageoftheconductiveroutesofatriumsmightintervenetheinitiationandmaintenanceofsom…     

落叶松阿拉伯半乳聚糖滴丸制备工艺及其速释机制研究

目的:研究落叶松阿拉伯半乳聚糖滴丸的制备工艺并初步探讨其速释机制。方法:采用正交设计对滴丸制备工艺进行优化,并通过相图分析和DSC分析研究滴丸的速释机制。结果与结论:滴丸制备最佳的工艺条件为药液温度75℃,二甲基硅油冷凝液上部温度30℃,滴头与冷凝液的距离6cm,滴速为30滴/min;相图分析和DSC分析结果显示在AG-PEG4000固体分散体中形成了某种形式的复合物,使熔点降低,药物在基质中的溶解度增加而达到速释。     

妊娠高血压综合征亚甲基四氢叶酸还原酶基因和血管紧张素转换酶基因多态性研究

目的　探讨N5,N10 亚甲基四氢叶酸还原酶 (methyenetetrahydrofolatereductase ,MTH FR)基因和血管紧张素转换酶 (angiotensin convertionenzyme,ACE)基因多态性与妊娠高血压综合征的关系。　方法　应用多聚酶链反应 限制性内切酶片段长度多态性 (PCR RFLP)技术检测 6 2例妊娠高血压综合征 (妊高征组 )患者及 12 0例正常妊娠 (对照组 )的ACE和MTHFR基因多态性。　结果　妊高征组MTHFR基因T/T基因型频率 ( 2 7% )显著高于对照组 ( 15 % ) (P <0 .0 5 ) ,T等位基因频率 ( 5 2 % )也显著高于对照组 ( 39% ) (P <0 .0 1) ,妊高征组ACE基因缺失型纯合子 (DD)频率( 4 0 % )显著高于对照组的 ( 10 % ) (P <0 .0 1) ,缺失型 (D型 )等位基因频率 ( 6 0 % )显著高于对照组的( 2 9% ) (P <0 .0 1)。MTHFR基因T等位基因与ACE基因D等位基因之间存在协同作用。　结论　MTHFR基因和ACE基因多态与妊高征的发病有关 ,ACE基因与MTHFR基因之间可能有协同作用     

栽培条叶龙胆各形态类型龙胆苦苷含量的测定

目的 :研究条叶龙胆栽培种群中形态变异与根中龙胆苦苷含量之间的相关性 ,探讨条叶龙胆有效成分高含量育种的可行性。方法 :自条叶龙胆栽培种群中选出 5个形态类型 ,即正常 (野生 )型、白花型、粗根型、宽叶Ⅰ型和宽叶Ⅱ型 ,采用高效液相色谱法测定根中龙胆苦苷含量。结果 :不同类型之间的龙胆苦苷含量差异较大 ,以粗根型为最高 ,其他依次为正常 (野生 )型、宽叶Ⅰ型、白花型、宽叶Ⅱ型 ;而同一类型的根系中龙胆苦苷含量与根龄呈正相关 ,即 3龄根 >2龄根 >1龄根。结论 :栽培条叶龙胆在形态上发生明显变异的同时有效成分含量亦发生显著变化 ,进行高含量育种是可行的 ,可以以某一形态性状作为高含量育种的选择指标。     

限窗滑动线性傅里叶拟合在人体震颤预估滤波中的应用

背景:为抑制人体的震颤运动,各国研究人员试图设计出一套可穿戴机器人辅助抑震系统。目的:分析介绍了针对震颤滤波预估常用的线性傅里叶拟合算法及其衍生算法,并在此基础上提出了改进算法。方法:提出一种引入了加权线性傅里叶拟合算法变基频带限线性傅里叶拟合改进算法,迭代的过程中可随着对象的改变而发生改变,频带设定了一定约束条件以保证算法的滤波特性,限制了频带的变化范围,即限定了一个大的通频带,通频窗口只能在所设定的这个范围内进行滑动,所提出的这种算法为限窗滑动的线形傅里叶拟合。结果及结论:该算法的适应性得到了拓宽,对震颤滤波预估具有更强的适应性与准确性。     

Studies on the L-2-hydroxy-acid oxidase 2 catalyzed metabolism of S-mandelic acid and its analogues

Mandelic acid (MA) is generally used as a biomarker of the exposure of styrene, which is classified as a class of hazardous environmental pollutants, and also used as an important chiral intermediate in pharmaceutical industry. The previous studies have found the excretion of phenylglyoxylic acid (PGA) in human and rat, a metabolite of MA, was mainly from S-MA rather than R-MA. The metabolic mechanism, however, is not clear. In order to explore the possible metabolic mechanism, the enzyme types involved in the stereoselectivity metabolism of MA were firstly studied, and then human and rat long-chain 2-hydroxy-acid oxidase 2 (HAO2) were recombinantly expressed to study the metabolic profiles of S-MA and its analogues. The results indicated that HAO2 might catalyze the stereoselectivity metabolism of S-MA in rats. Human HAO2 (hHAO2) and rat HAO2 (rHAO2) isozymes β₁ and β₂ were successfully cloned and expressed with high purity and good enzyme activities. The enzyme kinetic profiles of these enzymes were different for S-MA and analogues. The order of catalytic efficiency for hHAO2 and rHAO2, however, was reverse. It might be relevance to the difference in active amino acid residues and loop 4 in human and rat L-2-hydroxy acid oxidase isozyme B crystal structures.     

对旋轴流通风机流场预测及两级电机功率匹配研究

对旋风机是矿井通风系统的重要组成部分，其安全稳定的运行是煤矿工人生命安全的保障。针对在长距离送风状态下，对旋风机风量显著减小、前后两级电机功率匹配难度加大的问题，依据流体动力学原理(Computational Fluid Dynamics，CFD)，采用对旋风机全域流体场数值模拟方法，对两级对旋叶轮性能与两级电动机性能的“线(点对点)”匹配进行研究。仿真结果揭示了对旋轴流通风机流场内部气流的真实流动规律以及两级电机轴功率匹配情况。将数值模拟结果和实验数据进行对比，验证该数值模拟方法的准确性，同时验证通过改变叶片安装角提高风机运行效率的可行性，为高性能对旋风机调速控制和节能控制提供理论依据。     

窄带成像技术在子宫内膜病变诊断中的应用

目的:探讨窄带成像技术(NBI)在子宫内膜病变诊断中的临床应用价值.方法:400例行宫腔镜检查的患者同时进行NBI和白光(WL)宫腔镜检查,将检查的结果与病理结果进行比较.结果:WL宫腔镜诊断、NBI宫腔镜诊断与病理诊断的结果一致性好,WL与NBI宫腔镜诊断一致性好.NBI宫腔镜诊断的符合率较WL宫腔镜检查高.在区分正...