In vitro and in vivo investigation of bacterial cellulose dressing containing uniform silver sulfadiazine nanoparticles for burn wound healing

Silver sulfadiazine(SSD) particles in homogeneous dispersion state were prepared by an ultrasonic method and then nano- and microparticles were separated using centrifugation. SSD particles with narrow size distribution were impregnated with bacterial cellulose(BC) to produce BC–SSD composite membrane used as burn wound dressing. A scanning electron microscope(SEM) was used to examine the surface morphology of BC–SSD membranes. The incorporation of SSD in BC–SSD was confirmed by X-ray diffraction(XRD). Antimicrobial tests in vitro indicated that BC–SSD showed excellent antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The effects of BC–SSD on burn wound healing were assessed by rat models. The comparative study confirmed that the wound treated with BC–SSD showed high healing rate. The bacteria count in BC–SSD group was far less than control group. Histological analysis showed that epithelialization progressed better in wound treated with BC–SSD. These values demonstrated that the BC–SSD composite membrane could be a promising wound dressing for burn.     

提高醋酸纤维薄膜电泳实验成功率的探讨

针对人血清蛋白醋酸纤维薄膜电泳学生实验中薄膜选择和处理不当、点样不均匀，血清蛋白分离不良、搭桥不规范，产生斜泳、电泳条件掌握不好，区带分离不开、漂洗时膜重叠，造成血清蛋白粘连、染色不好，背景和区带不清晰等6个容易出现问题的环节，收集、展示了上述原因而导致实验失败的图谱，并与实验成功的图谱作对照。对实验的各个操作环节进行了深入探讨、提出了具体改进的措施，使学生一次成功率达到90%以上。该文提高教学质量具有重要意义。     

STUDY ON THE BIODEGRADATION OF CELLULOSE FIBER/BASALTIC FIBER COMPOSITE PAPERBOARD

INTRODUCTIONThe Biodegradation of cellulose fiber/basaltic fiber composite paperboard prepared by reference [1] was studied experimentally and the influence factors on the biodegradation velocity were researched. EXPERIMENTALExperimentalEquipmentThe equipment of the biodegradation experiment is shown in figure 1. The carbon dioxide gas was removed when the compressed air generated by air pump passed through the taper bottle filled with sodium hydroxide solution, and then, the air tra…     

生物纤维素及其与多糖共混纤维的结构与性能

以生物纤维素、海藻酸和壳聚糖为原料,离子液体为溶剂,采用湿法纺丝工艺,制备了生物纤维素纤维、生物纤维素/海藻酸共混纤维和生物纤维素/壳聚糖共混纤维,研究了纤维的SEM形貌、红外光谱、力学性能、吸湿性、染色性能和抗菌性能。结果表明:纤维粗细均匀,且纵向表面光滑,无裂纹,截面近似为圆形;三种纤维的断裂强度在3.0 cN/dtex左右,接近棉纤维,比粘胶纤维好很多;三种纤维的吸湿性能均比较优异,远优于棉纤维,其中生物纤维素/海藻酸共混纤维的吸湿性最佳,其次是生物纤维素/壳聚糖共混纤维;生物纤维素/壳聚糖复合纤维的抗菌效果明显且抗菌持久性好,经过15次洗涤之后,对大肠杆菌和金黄色葡萄球菌的抑菌率仍然大于90%,具有良好的抗菌效果。     

两株细菌对偶氮染料活性艳红X—3B脱色的研究

从太原市纺织绒染厂废水处理站曝气池分离筛选到一株假单胞菌和一株黄单胞菌,探讨了这两株菌在不同碳源、不同ｐＨ和不同温度条件下对活性艳红Ｘ—３Ｂ的脱色效果。试验结果表明,假单胞菌和黄单胞菌分别以葡萄糖,果糖和无水乙酸钠为碳源时,脱色效果都较好,且黄单胞菌以可溶性淀粉作碳源时也有较高的脱色率。这两株菌脱色的最适ｐＨ均为８．０。假单胞菌脱色的最适温度为２５℃,黄单胞菌脱色的最适温度为３０℃。     

Mechanical properties of carbonfi ber/cellulose composite papers modified by hot-melting fibers

Carbon fiber(CF)/cellulose(CLS) composite papers were prepared by papermaking techniques and hot-melting fibers were used for modification. The mechanical properties of the obtained composite papers with different CF,CLS and hot-melting fiber ratios were studied and further discussed. It is observed that,for both CF/CLS composite papers and those modified by hot-melting fibers,the normal stress firstly increases and then declines with the addition of carbon fibers. The results also show that with the addition of hot-melting fibers,the modified papers exhibit enhanced mechanical performance compared to CF/CLS composite papers. Through SEM characterization,it is confirmed that the improvement of mechanical properties attributes to the reinforcement of adhesive binding at the fiber overlap nodes. Also,through four-probe method,the resistivity and the electrical performance of the modified and unmodified papers were characterized and the result shows that the hot-melting fiber modification brings no harm to the electrical properties.     

利用PCR-DGGE分析胆固醇结石中细菌群落结构

本研究运用聚合酶链式反应-变性梯度凝胶电泳（PCR-DGGE）方法对来自8名胆石病人的8份胆固醇结石和4份胆汁样品中细菌群落结构进行分析和比较研究。DGGE结果显示,胆固醇结石中细菌含有Enterococcus,Pseudomonas等13个属细菌,其中Pseudomonas检出率最高,Klebsiella和Bacillus两个属细菌含量较多;胆固醇结石中6个属细菌在胆汁中也检测到。不同病人之间胆固醇结石细菌群落结构高度相似,但胆汁相似度较低;胆固醇结石中细菌群落结构与胆汁细菌群落结构最高相似度仅为38%,胆汁中细菌种类虽与胆固醇结石有同源性,但细菌群落结构差异较大。因此,导致胆固醇结石形成的细菌种类有一定偏好性,不因人而异,临床上对这些细菌的控制将有利于抑制结石的生成。     

细菌性鱼病的免疫研究现状

概述了细菌性鱼病的免疫研究现状,主要介绍鱼用细菌性疫苗的研制、接种途径及免疫效果的评价,指出了鱼类免疫研究的发展前景及其存在的问题     

森林碳汇计量方法的研究

通过植物分子式的方法确定不同树种的含碳量,以此为参数对我国的森林碳汇量进行了估算。结果表明:该计量方式既简单易行,又具有规范性及重复操作性,可动态预测我国森林碳汇量。并且,通过我国几次森林资源清查数据和森林资源系统仿真模型,该方法可对我国森林碳汇功能发展趋势作出动态预测。     

抗皱纤维素膜的制备与性能研究

利用氢氧化钠-尿素-硫脲溶剂体系将纤维素浆粕溶解,向溶液中添加1,2,3,4-丁烷四羧酸,配制成纤维素纺丝液并制得了纤维素膜.通过红外光谱分析和折皱回复角、断裂强力等测试,表征了膜的结构和性能.结果表明,该纤维素膜在一定条件下可以发生酯化交联反应并具有抗皱性能.改变1,2,3,4-丁烷四羧酸的用量、反应温度和反应时间,可以在纤维素膜的折皱回复角和断裂强力之间取得某种平衡.