Preparation and characterization of a magnetic microsphere synthesized from sucrose allyl ether for transcatheter arterial embolization

The polymerization of allyl monomers has been reported as notoriously difficult because of degradative chain transfer induced by the allyl radical as a primary radical with resonance-stabilized structure. A favorable approach is to produce polymers from inert monomers by using photodriven radical–mediated cyclization reaction (PRMC). In this study, Fe₃O₄ at sucrose allyl ether (Fe₃O₄@SAE) magnetic microspheres with sucrose as the skeleton and encapsulated nanomagnetic particles was prepared by PRMC. Its morphology and performance were characterized by using microscope, infrared, thermogravimetric and differential scanning calorimetry, scanning electron microscope/energy-dispersive spectrometer, and vibrating sample magnetometer. The feasibility as an embolic agent was evaluated by catheter transportability and cell compatibility. The results show that Fe₃O₄@SAE (sucrose allyl ether) magnetic microspheres have an average particle size of 371 μm, regular spherical shape, good dispersion, basically non-toxicity, and good cell compatibility. It has a certain degree of magnetism and can use alternating magnetic fields to achieve targeted embolization.     

Magnetic resonance tissue analysis of acute renal vascular occlusion in the rabbit: enhancement with gadolinium-DTPA complex

In order to assess the sensitivity of nuclear magnetic resonance (NMR) in detecting acute renal vascular insufficiency, in vitro NMR spectroscopy (at 0.25 T) was performed on rabbit renal cortices following 45 min of unilateral renal artery (RAO) or renal vein occlusion (RVO). Data were obtained both with and without paramagnetic enhancement with gadolinium-DTPA (Gd-DTPA). In the absence of contrast material, RVO was distinguished by markedly elevated spin-lattice (T1) and spin-spin (T2) relaxation times when compared to the contralateral control kidney [mean increase of 29% in T1 (p less than 0.001) and 19% in T2 (p less than .001)]. RAO produced no change in T1 (p = N.S.) and a small change in T2 (mean increase of 11%, p less than .01). Five min following injection of 0.05 mM/kg of Gd-DTPA, relaxation times of control kidneys were markedly shortened [mean decrease 75% in T1 (p less than .001) and 12% in T2 (p less than 0.01)]. With Gd-DTPA, kidneys with RVO continued to have elevated T1 and T2 relaxation time, and kidneys with RAO maintained their essentially normal pre-contrast relaxation time values. We conclude that non-contrast NMR tissue analysis clearly differentiated normal from congested (RVO) kidneys, but not from acutely ischemic (RAO) kidneys. Paramagnetic enhancement with Gd-DTPA allows the differentiation of normally perfused from acutely ischemic or congested kidneys.     

The phenomenon of cell membrane tensile stress accumulation and its effect on endothelin-1 secretion by vascular endothelial cells

Theoretical analysis has shown that that the tensile stress in the upper cell membrane of the vascular endothelium could accumulate upstream to a very high level despite of the identical shear environments. This phenomenon is called cell membrane tension accumulation (CMTA). To verify the theoretical analysis, the secretion of endothelin-1 (ET-1) by a paired human umbilical vein segments with different lengths (10 and 15 cm, respectively) were measured. The results clearly showed highly significant differences in the secretion rates of ET-1 between the 10 cm-long vein (segment A) and the 15 cm-long vein (segment B) under the same shear stress level of 0.48 N/m². When exposed to a shear stress of 0.48 N/m² for 24 h, segment B secreted ET-1 at an average rate of 34.9154±0.9830 pg/cm² h, almost 14% higher than the average rate of 30.6274±0.4912 pg/cm² h recorded by segment A (P<0.01). The present study, therefore, confirms that CMTA does in fact occur in the blood vessel. This phenomenon affects the secretion of ET-1 by vascular endothelial cells, and may be more important than shear stress in its effect on the metabolism and biological function of endothelial cells.     

新型苯基噻吩-2-基甲酮类化合物的合成及其对人脐静脉内皮细胞的保护活性

合成了13个具有新型结构的苯基(噻吩-2-基)甲酮类化合物,其中3个化合物(9b,10b,11b)未见文献报道,目标化合物的结构均经ESI-MS、1H NMR和13C NMR等技术手段进行了确证。 对H2O2诱导的人脐静脉内皮细胞(HUVECs)氧化损伤保护活性的结果显示,对位甲氧基以及两个氯原子取代的活性较好。 初步构效关系表明,苯基噻吩甲酮母环上取代基的位置、数目、类型是影响化合物活性的主要原因。     

小鼠股动脉及股静脉插管手术模型制备方法

介绍一种小鼠经股动脉及股静脉插管手术模型．具体方法为：小鼠经异氟烷麻醉后,无菌切开小鼠的颈部及腹股沟皮肤,将已制备好的2根J形塑料导管植入皮下,并从颈部引出,经股动脉及股静脉造口,将J端导管分别插入股动脉及股静脉内．再将双股拧成麻花状的细铁丝固定于颈部肌肉,并与引出的塑料导管捆绑在一起．固定细铁丝,将塑料导管通过旋转输液阀与输液泵相连．手术后,输液泵持续灌注20U·mL^-1的肝素（12～15μL·h^-1）,以防止塑料导管内凝血．手术后1～2d,动物基本都能恢复到正常生理状况．手术感染率低于6％,7d动脉导管堵塞率低于5％．这种经显微外科手术建立的动物模型,可在动物清醒、自由活动状态下,无痛苦地完成采血、给药及血压等生命体征的系统监测,被广泛应用．于药理学、毒理学等各学科的实验研究中．     

Lee's extremum principle and the large deflection response of dynamically loaded plastic structures

An approximate method based on Lee's extremum principle is introduced to study the large deflections of dynamically loaded plastic structures. As an example, the evolutionary mode of an impulsively loaded rigid-perfectly plastic portal frame is determined and then compared with the experimental results [8] and with the large deflection complete solution obtained previously [9]. It is found that the evolutionary modal solution may approach the complete solution if the modes are appropriately chosen.     

手背静脉图像预处理算法研究

静脉识别是一种新兴的生物特征识别技术。介绍了静脉图像的采集原理,根据静脉血管的特点,重点对静脉图像预处理进行了研究。静脉图像预处理可分为静脉图像的标准化和静脉图像的二值化两个部分。针对二值化问题,提出了彩动态阈值法对静脉图像进行处理和增强,得到了较好的结果。     

Screening and analyzing the potential bioactive components from Shaofu Zhuyu decoction, using human umbilical vein endothelial cell extraction and high-performance liquid chromatography coupled with mass spectrometry

In this paper, a useful method for screening and analyzing the potential bioactive components in bioassay-guided fraction (SF-11) from Shaofu Zhuyu decoction was developed using human umbilical vein endothelial cell (HUVEC) extraction and high-performance liquid chromatography coupled with Q-TOF/MS spectrometry. In addition, the protective effects on HUVEC damage induced by adrenaline in vitro were also investigated. The results showed that SF-11 significantly inhibited the endothelin (ET) release and reversed the NO secretion of HUVEC (p < 0.05), and promoted the PGI(2) release of HUVEC (p < 0.05). Two effective components, paeoniflorin and typhaneoside, from SF-11 were screened and identified using live cell extract and HPLC coupled with Q-TOF/MS spectrometry. The compounds, paeoniflorin and typhaneoside, showed significantly inhibiting effects on the ET release and reversing of NO secretion of HUVEC (p < 0.05), with similar effects to SF-11, and promoting the PGI(2) release of HUVEC at the concentration of 0.208 and 0.013 micromol/mL, respectively (p < 0.05). These data indicated that the method of live cell extraction coupled with HPLC-MS technology is feasible, rapid and useful for screening and analyzing potential bioactive components from TCMs.     

隧道峒口污染物扩散控制方案的研究

采用三维数值模拟的方法,对隧道峒口污染物的扩散情况进行了预测和分析,揭示了在不同风向条件下,隧道峒口废气的扩散特征,并根据计算结果提出了一种较为经济的控制污染物排放的方案,对工程设计具有一定的指导意义。     

多谱段短波红外小鼠静脉荧光观测成像研究

短波红外(short-wave infrared,SWIR)一般指900～1700 nm的光波段,是肉眼不可见的光波段,这种波段目前主流的探测器以InGaAs为主,主要用于军事、生物以及材料光谱分析等领域.短波红外荧光成像以其对生物组织光学损伤小、成像深度大、成像信噪比高、空间和时间成像分辨率高等特点,使得基于InGa...