丹参素对大鼠局灶性脑缺血再灌注损伤的保护作用

目的研究丹参素对大鼠局灶性脑缺血再灌注损伤的保护作用,并初步探讨其作用机制.方法用线栓法制备大鼠局灶性脑缺血再灌注损伤模型,通过神经功能学评分、苏木素和伊红(HE)染色及流式细胞术检测丹参素对大鼠脑缺血再灌注损伤后行为学、缺血侧脑组织病理形态学及神经细胞凋亡的影响.结果丹参素可明显改善脑缺血大鼠神经功能缺损体征,减轻脑组织病理形态学损伤,降低神经细胞凋亡百分率.结论丹参素对大鼠局灶性脑缺血再灌注损伤具有保护作用,其作用机制可能与抑制神经细胞凋亡有关.     

The effect of gratifications derived from use of the social networking site Qzone on Chinese adolescents’ positive mood

Drawing from Uses and Gratifications Theory, this study explores the influence of the gratifications derived from use of the social networking site Qzone on Chinese adolescents’ positive mood. Qzone is the social networking site that is most preferred and used by Chinese adolescents. Hypothesized relationships are analyzed by structural equation analysis in a sample of 220 Chinese adolescents aged 14–19 with an online Qzone profile. Gratifications that Chinese adolescents receive from use of the online social network Qzone, such as socializing, information-seeking, and entertainment are found to have a significantly positive influence on their positive mood. Findings of this study extend the existing theoretical framework on the application of the Uses and Gratifications Theory to social networking sites. In addition, findings are in line with those of a number of authors who suggest that social networking site use may have positive consequences for teenagers. Theoretical and practical implications are discussed.     

Recent Advances in Inhibitors of Bacterial Fatty Acid Synthesis Type II (FASII) System Enzymes as Potential Antibacterial Agents

Bacterial infections are a constant and serious threat to human health. With the increase of multidrug resistance of clinically pathogenic bacteria, common antibiotic therapies have been less effective. Fatty acid synthesis type II (FASII) system enzymes are essential for bacterial membrane lipid biosynthesis and represent increasingly promising targets for the discovery of antibacterial agents with new mechanisms of action. This review highlights recent advances in inhibitors of bacterial FASII as potential antibacterial agents, paying special attention to the activities, mechanisms, and structure–activity relationships of those inhibitors that mainly target β‐ketoacyl‐ACP synthase, β‐ketoacyl‐ACP reductase, β‐hydroxyacyl‐ACP dehydratase, and enoyl‐ACP reductase. Although inhibitors with low nanomolar and selective activity against various bacterial FASII have entered clinical trials, further research is needed to expand upon both available and yet unknown scaffolds to identify new FASII inhibitors that may have antibacterial potential, particularly against resistant bacterial strains.     

Erratum to: Experimental research on overlying strata movement and fracture evolution in pillarless stress-relief mining

International Journal of Coal Science & Technology -     

工控组态在汽车厂区域监控系统中的应用

在卡车装配线电气控制设计中,充分利用主控组态软件技术,实现了组态软件之间的远程数据访问。     

微量溶解氧传感器的研制

根据Clark原理设计了一种极谱式微量溶解氧传感器,传感器具有制作方法简便,使用寿命长等特点,且测量精度可以达到μg/L级别。所设计的传感器具有温度补偿功能,有效提高了测量精度。同时对透氧膜的厚度与传感器响应时间进行了讨论,对电极的制作材料选择进行了对比,为今后微量溶解氧传感器的制作具有相当的指导意义。通过与瑞士Orbisphere公司的溶解氧检测仪进行对比发现所设计的微量溶解氧传感器满足精度要求,符合设计要求。     

Morphology,in vivo distribution and antitumor activity of bexarotene nanocrystals in lung cancer

Abstract

The objective of this study was to develop and evaluate the morphology, biodistribution and antitumor activity of bexarotene nanocrystals delivery system. The morphology was investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscope and bexarotene nanocrystals exhibited the advantages of making the efficacy more steady and durable compared with control group in lung with less cardiac accumulation as shown by biodistribution studies in vivo. In addition, MTT assay, flow cytometry analysis, observation of morphological changes and apoptotic body demonstrated that bexarotene nanocrystals could significantly enhance the in vitro cytotoxicity and induced G1 cycle arrest and apoptosis against A549 cells. Also, bexarotene nanocrystals had significant antitumor activity in mice bearing A549 cell line. This finding was correlated with both in vitro and in vivo. Thereby, the overall results suggest that the bexarotene nanocrystals represent a potential source of medicine, which made bexarotene nanocrystals a promising candidate for the treatment of lung cancer.     

Visible laser microfabrication of transparent plastic using Au nanoparticles-dispersed polymer film

A polymer film in which Au nanoparticles with average diameter of around 3 nm dispersed in ethylcellulose was applied to an absorber for laser microfabrication of a transparent plastic. Since the polymer film has a strong absorption at the wavelength of around 530 nm, it can be micromachined using focused low power Nd:YVO₄–SHG laser (CW, wavelength of 532 nm). When laser beam was irradiated on the polymer film coated on transparent substrate, the substrate under the polymer film which has no absorbance in the range of wavelength of laser beam was processed. A micropattern was clearly fabricated on transparent poly(methyl methacrylate) and polyethylene terephthalate using our polymer film. In poly(methyl methacrylate) substrate, the processed depth showed a maximum at the polymer film thickness of 15 μm under the condition of laser power of 23 mW. Finally, laser marking test on the transparent poly(methyl methacrylate) was demonstrated as an application of our system using the optimal polymer film thickness.     

Shrinkage properties of a modified dental resin composites containing a novel spiro-orthocarbonate expanding monomer

ObjectivesThis study investigated the photopolymerization-induced shrinkage properties of conventional methacrylate-based composites modified by a novel spiro-orthocarbonate (SOC) expanding monomer.MethodsThe epoxy monomer and SOC expanding monomer were added to a methacrylate-based resin matrix at five different ratios ranging from 20 wt.% (SOC + Epoxy) (group 1) to 60 wt.% (SOC + Epoxy) (group 5). Volumetric shrinkage and contraction stress developing after polymerization were measured using X-ray micro-computed tomography and a universal testing machine, respectively.ResultsThe volumetric shrinkage of the resin composite samples ranged from 0.92% (group 5) to 3.85% (control group) 30 min after light curing. Group 5 had the lowest volumetric shrinkage (p < 0.05), followed by groups 4, 3, 2 and 1. The contraction stress of the materials ranged from 1.86 MPa (group 5) to 3.56 MPa (control group). The lowest contraction stress was also observed in group 5, 30 min after curing (p < 0.05).ConclusionIncluding SOC expanding monomer reduced volumetric shrinkage and contraction stress of composites in comparison with conventional methacrylate-based composites.     

Improved determination of D-glucosamine hydrochloride in health foods by HPLC using 7-fluoro-4-nitrobenzo-2-oxa-l,3-diazole as a derivative

Abstract: This article presents an improved method to detect d ‐glucosamine hydrochloride in health foods. A simple precolumn derivatization procedure with 7‐flouro‐4‐nitrobenzo‐2‐oxa‐1,3‐diazole (NBD‐F) reagent was employed. The separation of the derivatized d ‐glucosamine hydrochloride (NBD‐d ‐glucosamine hydrochloride) was performed using a mobile phase consisting of acetonitrile, potassium dihydrogen phosphate (0.01 mol/L), and trifluoroacetic acid (350:649.74:0.26, volume ratio) at a flow rate of 1.0 mL/min with the column temperature 35 °C. Under the optimum chromatographic conditions, the peak area of NBD‐d ‐glucosamine hydrochloride compared with its absolute value of the peak area of NBD‐d ‐glucosamine hydrochloride in a standard solution concentration range from 1.0 to 500.0 mg/L showed a good linear calibration (R = 0.9999). Recoveries, at spiked concentrations of 10.0, 40.0, and 500.0 mg/L, varied between 97.2% and 102.6% with relative standard deviations ranging from 0.4% to 1.5%. The present method provides sufficient sensitivity as reflected by the values of limit of detection (LOD) and limit of quantification (LOQ). LOD was determined from the signal‐to‐noise ratios (S/N) of NBD‐d ‐glucosamine hydrochloride peak of at least 3 in the recovery test at 0.02 mg/L, and the estimated LOQ was 0.06 mg/L (S/N = 10). The proposed method was successfully applicable to detect d ‐glucosamine hydrochloride in health foods and drugs containing a variety of complex materials.