Four new dammarane-type triterpenes derivatives from hydrolyzate of total Gynostemma pentaphyllum saponins and their bioactivities

Phytochemical investigation of hydrolysate of total G. pentaphyllum saponins led to the isolation of four novel triterpenes, Gypensapogenin U (1), Gypensapogenin V (2), Gypensapogenin W (3) and Gypensapogenin X (4). The structures of these compounds were identified by 1D, 2D-NMR and HR-ESI-MS evidences. Additionally, the protective activity of these new compounds against cardiomyocytes injury induced by H₂O₂ and their cytotoxic activity against t-HSC/Cl-6 cells were evaluated.     

爆炸冲击波作用下人体肺部的损伤

为探究肺部爆炸伤的致伤机制与评价指标,构建了人体-爆炸流场有限元模型,通过与爆炸事故中人员损伤情况比对,验证了模型的有效性。共进行39个爆炸工况的数值模拟,通过改变爆炸当量与距离,使得胸部受到不同量级爆炸载荷作用,肺部损伤等级从无损伤到严重损伤。通过分析爆炸流场分布、胸腔动力学响应、肺部应力分布等阐明肺部爆炸伤的力学机制。基于人体有限元模型输出的损伤响应,提出肺部爆炸伤的评价指标。研究结果表明：在爆炸载荷作用下,胸前壁高速撞击胸腔脏器,导致肺部产生应力波。随后在惯性作用下,胸前壁持续挤压胸腔脏器,并造成胸腔变形。应力波是造成肺部损伤的主要原因,胸腔变形挤压肺部造成的损伤风险较低。肺部损伤集中在靠近胸前壁及心脏的区域。胸骨速度峰值和胸骨加速度峰值可作为肺部爆炸伤的评价指标。胸部压缩量及黏性响应系数不能反映应力波对肺部造成的损伤,不适合评价肺部爆炸伤。

     

An analytical poroelastic model for laboratorial mechanical testing of the articular cartilage (AC)

The articular cartilage (AC) can be seen as a biphasic poroelastic material. The cartilage deformation under compression mainly leads to an interstitial fluid flow in the porous solid phase. In this paper, an analytical poroelastic model for the AC under laboratorial mechanical testing is developed. The solutions of interstitial fluid pressure and velocity are obtained. The results show the following facts. (i) Both the pressure and fluid velocity amplitudes are proportional to the strain loading amplitude. (ii) Both the amplitudes of pore fluid pressure and velocity in the AC depend more on the loading amplitude than on the frequency. Thus, in order to obtain the considerable fluid stimulus for the AC cell responses, the most effective way is to increase the loading amplitude rather than the frequency. (iii) Both the interstitial fluid pressure and velocity are strongly affected by permeability variations. This model can be used in experimental tests of the parameters of AC or other poroelastic materials, and in research of mechanotransduction and injury mechanism involved interstitial fluid flow.     

基于人体损伤的中低速正面碰撞气囊点火状态分析方法研究

为降低驾驶员在中低速碰撞下受到的损伤, 利用2010年版丰田Yaris整车模型建立100%正面刚性壁碰撞有限元模型, 并根据驾驶员舱布置及相关法规要求建立Madymo约束系统仿真模型, 以验证有限元模型的准确性. 利用建立的碰撞模型, 在中低速碰撞中对不同气囊点火状态下的驾驶员所受损伤进行仿真. 结果表明, 该车型在35 km●h^-1及以上车速时, 点爆气囊能有效减少驾驶员损伤; 30 km●h^-1及以下车速时, 气囊点火会对驾驶员造成额外伤害; 中低速碰撞下, 驾驶员的胸部损伤程度较头部更容易受气囊点火时间影响.     

构造和评价奖惩系统的新方法

当知道一个奖惩系统的等级和保费水平时,利用信息熵提出并得到奖惩系统的理想概率分布．在保单中考虑人身伤亡索赔次数的二元模型,将奖惩系统的平稳概率分布与理想概率分布的差异,通过卡方值与多余度分别表现出来,将其作为评价奖惩系统的一个新工具．     

Recent advances in clinical microdialysis

Clinical microdialysis (MD) is a minimally invasive sampling technique that offers selective in-vivo measurement of free, active drug or biomolecule concentrations in human tissues and organs. From a regulatory perspective, MD can thus be seen as a suitable scientific tool that meets regulatory requirements for the study of tissue distribution or bioequivalence during drug development. From a clinical perspective, the use of MD in different applications has shown the potential to rationalize drug-dosing regimens and to influence clinical decision-making, although validation and correlation of MD-derived results with clinical response are required to promote routine clinical use of the technique. From an analytical perspective, highly sensitive analytical systems have increasingly become available for MD-sample analysis, and these have further improved the quality and the power of MD-derived information. Given the constant development in recent years, MD data might become an important part of new drug submissions and clinical treatment algorithms, and might positively influence patient benefit in the future.     

毛冬青总皂苷对AHNP诱导肝损伤大鼠骨中7种微量元素的影响

目的探讨了毛冬青总皂苷对AHNP诱导肝损伤大鼠骨中微量元素的影响。方法应用逆行胰胆管术注射牛磺胆酸钠（TAC）复制急性出血坏死性胰腺炎（AHNP）大鼠实验动物模型,进行了毛冬青总皂苷（高、低剂量）的治疗。观察了5组（假手术对照组、AHNP模型组、毛冬青总皂苷高剂量组、毛冬青总皂苷低剂量组、尼尔雌醇组、）大鼠股骨中Cu、Mn、Fe、Zn、Pb、Mg和ca等微量元素的变化。结果统计学结果显示与AHNP模型组比较,毛冬青总皂苷能提高AHNP大鼠骨质中cu、Fe、Mn、Mg、Ca等元素的含量,尼尔雌醇组中的zn含量提高,毛冬青总皂苷组中的zn含量反而下降;尼尔雌醇组与毛冬青总皂苷组中Pb含量下降明显。结论说明毛冬青总皂苷的治疗作用并不是单一的,可以认为中药毛冬青总皂苷是通过发挥对人体整体的调节作用来调节骨骼中微量元素的变化,改变骨质的代谢情况,促进骨密度的提高。     

An ultra high performance liquid chromatography with tandem mass spectrometry method for plasma and cerebrospinal fluid pharmacokinetics of rhein in patients with traumatic brain injury after administration of rhubarb decoction

Damage of blood–brain barrier is a common result of traumatic brain injury. This damage can open the blood–brain barrier and allow drug passage. An ultraperformance liquid chromatography with tandem mass spectrometry method was established to determine the concentration of rhein in the biofluids (plasma and cerebrospinal fluid) of patients with a compromised blood–brain barrier following traumatic brain injury after rhubarb administration. Furthermore, the pharmacokinetic profiles were analyzed. A triple‐quadruple tandem mass spectrometer with electrospray ionization was used for rhein detection. The mass transition followed was m/z 283.06→239.0. The calibration curve was linear in the concentration range of 10–8000 ng/mL for the biofluids. The intra‐ and interday precisions were less than 10%. The relative standard deviation of recovery was less than 15% in biological matrices. The pharmacokinetic data showed that rhein was rapidly transported into biofluids, and exhibited a peak concentration 1 h after rhubarb administration. The elimination rate of rhein was slow. The AUC_{cerebrospinal fluid}/AUC_plasma (AUC is area under curve) of rhein was approximately 17%, indicating that portions of rhein could pass the impaired blood–brain barrier. The method was successfully applied to quantify rhein in the biofluids of all patients. The data presented can help to guide clinical applications of rhubarb for treating traumatic brain injury.     

From the Bench to the Field in Low‐Cost Diagnostics: Two Case Studies

Despite the growth of research in universities on point‐of‐care (POC) diagnostics for global health, most devices never leave the laboratory. The processes that move diagnostic technology from the laboratory to the field—the processes intended to evaluate operation and performance under realistic conditions—are more complicated than they might seem. Two case studies illustrate this process: the development of a paper‐based device to measure liver function, and the development of a device to identify sickle cell disease based on aqueous multiphase systems (AMPS) and differences in the densities of normal and sickled cells. Details of developing these devices provide strategies for forming partnerships, prototyping devices, designing studies, and evaluating POC diagnostics. Technical and procedural lessons drawn from these experiences may be useful to those designing diagnostic tests for developing countries, and more generally, technologies for use in resource‐limited environments.     

用多克隆抗体构建的夹心免疫传感器检测心肌肌钙蛋白I

用表面等离子体子共振生物传感器构建对心肌肌钙蛋白I特异性的免疫传感器检测心肌肌钙蛋白I,并建立两种检测方法:直接法的最低检测限为2.5μg/L,基于传感膜上的夹心免疫法的灵敏度为0.5μg/L,检测范围为0.5～20μg/L,批内及批间精密度分别为3.5%～4.9%,6.1%～7.4%;用夹心法及国外试剂盒对40名健康献血者和20例急性心肌梗死患者血清心肌肌钙蛋白I水平进行检测,两者符合率为95%.