胃促生长素使我们更愿意花钱购买食品

《每日科学》2011年7月15日报道:研究饮食行为各个方面的最重要的协会,摄食行为研究协会(SSIB)即将召开年会。将在这次年会上发表的研究表明,胃促生长素,一种自然产生的消化道激素,使我们更愿意花钱购买食品,而降低了购买非食品物品的意愿。     

交变磁场对水及生理盐水过冷过程的影响

为了研究磁场作用下水和生理盐水的过冷现象,搭建了可以实时测量记录冻结过程和磁场强度的试验台。20mL自来水或医用生理盐水被用作实验样本,磁场强度从0~64 G变化的50 Hz交变磁场被施加到样本上。实验结果发现交变磁场能够降低水和生理盐水的最低不结晶温度,水过冷度的增大与磁场强度能构成线性函数关系,生理盐水的过冷度增大与磁场强度能构成三次多项式函数关系;相同磁场强度下水的过冷度增加幅度大于生理盐水,在最大磁场强度(64 G)下水的过冷度增加了2.06℃而生理盐水过冷度增加了1.73℃;过冷度的增加导致过冷态时间延长,从而使得水体温度均匀性增加,推迟了成核时间。因此采用交变磁场能够增加水和生理盐水的过冷度,延长过冷时间,磁场的作用机理可能与水分子间的氢键形成和溶液中水合离子的洛伦兹力有关。     

初生仔猪链球菌病的免疫预防

针对初生仔猪的链球菌病，湖南省湘乡市畜牧局开展了初生仔猪链球菌病的早期免疫和超前免疫试验。1999年1月，在养猪户中选择4窝有链球菌病疫情的猪群中的健康仔猪或其上窝仔猪曾发生链球菌病的母猪所产仔猪共44头，于仔猪5日龄时，用生理盐水100mL稀释100头份猪败血性链球菌病活疫苗，用无针头注射器注入仔猪口内。     

超强吸水剂及其制备方法

本发明公开了一种超强吸水剂及其制备方法。预先将魔芋粉加水在一定温度下糊化后，通过比例泵加入以碱部分中和的丙烯酸系列单体、引发剂和交联剂，搅拌并通入氮气或氩气保护，一定温度引发接枝共聚反应后，以氮气或氩气伴随反应液喷射进入螺旋管式紊流反应器进行接枝共聚，反应一定时间后，螺旋挤出送入滚筒式薄膜成型干燥器，使反应物呈膜状干燥。干燥后产品呈薄膜片状，经粉碎成颗粒状产品。该工艺制备的产品对纯水的吸收率可达到500～2000倍，生理盐水的吸收率可达到80～200倍；     

多种117Snm(113Sn)-配体体系的形成条件及其与BSA的结合

以^117Sn^m(^113Sn)示踪法研究了Sn-DTPMP、Sn—DTPA、Sn-EDTMP、Sn—HEDTMP、Sn—TTHMP体系的形成条件，同时研究了不同标记体系与牛血清白蛋白(BSA)的结合性质。研究表明，除DTPA外，其他配体在较高浓度下均能与Sn^4 形成络合，但配体浓度较低时锡极易水解，用生理盐水稀释和增加体系pH均加剧水解。研究同时显示，水解锡标记体系与BSA有很强的结合，未水解锡标记体系与BSA的结合率远低于水解锡标记体系。     

Hank’s溶液和生理盐水中纯钛的复合微动腐蚀特性

采用球/甲面接触方式,进行纯钛(TA2/TA2)在Hank's溶液和生理盐水中的常温切向和径向复合微动腐蚀实验.实验接触角θ为45.,最大径向载荷Fmax为100、200和300N,微动循环周次为5×104次.在摩擦动力学分析和耗散能计算分析基础上,用扫描电镜(SEM)和激光共焦扫描显微镜(LCSM)测定了磨损量,分析磨损机制.结果表明:在Hank's溶液和生理盐水中,复合微动F-D曲线呈现准梯形和椭圆形二阶段特征:相同载荷条件下,TA2在Hank's溶液中材料损失量比在生理盐水中小,这与在相同条件下Hank's溶液中的耗散能比在生理盐水中小的结果一致.在二种介质条件下,TA2的复合微动磨损主要以磨粒磨损和剥层方式进行.     

Drilling Force and Temperature of Bone under Dry and Physiological Drilling Conditions

Many researches on drilling force and temperature have been done with the aim to reduce the labour intensiveness of surgery, avoid unnecessary damage and improve drilling quality. However, there has not been a systematic study of mid- and high-speed drilling under dry and physiological conditions（injection of saline）. Furthermore, there is no consensus on optimal drilling parameters. To study these parameters under dry and physiological drilling conditions, pig humerus bones are drilled with medical twist drills operated using a wide range of drilling speeds and feed rates. Drilling force and temperature are measured using a YDZ-II01W dynamometer and a NEC TVS-500EX thermal infrared imager, respectively, to evaluate internal bone damage. To evaluate drilling quality, bone debris and hole morphology are observed by SEM（scanning electron microscopy）. Changes in drilling force and temperature give similar results during drilling such that the value of each parameter peaks just before the drill penetrates through the osteon of the compact bone into the trabeculae of the spongy bone. Drilling temperatures under physiological conditions are much lower than those observed under dry conditions, while a larger drilling force occurs under physiological conditions than dry conditions. Drilling speed and feed rate have a significant influence on drilling force, temperature, bone debris and hole morphology. The investigation of the effect of drilling force and temperature on internal bone damage reveals that a drilling speed of 4500 r/min and a feed rate of 50 mm/min are recommended for bone drilling under physiological conditions. Drilling quality peaks under these optimal parameter conditions. This paper proposes the optimal drilling parameters under mid- and high-speed surgical drilling, considering internal bone damage and drilling quality, which can be looked as a reference for surgeons performing orthopedic operations.