4-(Ethoxycarbonyl) phenyl-1-amino-oxobutanoic acid-chitosan complex as a new matrix for silver nanocomposite film: preparation, characterization and antibacterial activity

The present work describes the preparation of new chitosan complex with 4-(ethoxycarbonyl) phenyl-1-amino-oxobutanoic acid (ETHA), as a matrix for silver nanoparticles to obtain a nanocomposite film by solution casing method. The characterization of the prepared nanocomposite film was made by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetry (TG) and scanning electron microscopy (SEM). The optical property of nanocomposite film was analyzed by UV-Visible and photo-luminescence (PL) spectroscopy. The nanocomposite film was screen for antibacterial activity with Staphylococcus aureus (gram positive), Pseudomonas aurigionasa (gram negative) and Escherichia coli (gram negative) bacteria by adopting the disk diffusion method. The result of antibacterial study revealed that the prepared nanocomposite film may be a promising candidate for wide range of bio-medical applications.     

薄膜包装对于柿果冷藏生理及品质变化的影响

冷藏条件下采用有孔的聚乙烯薄膜为包装材料贮藏‘尖柿’,研究了聚乙烯薄膜的保湿作用对果实质地、生理生化,以及失重、失鲜等变化进程的影响。结果表明：薄膜包装能有效地防止蒸腾失水、显著抑制失重率增加,减缓硬度下降,推迟呼吸、乙烯峰到来的时间,并降低峰值,抑制细胞膜透性的增大,使果实保持光洁、饱满的外观形态,县有良好的商品性。     

Making Forest of Bliss: The Film, the Book, the DVD, and the Breakthrough

Robert Gardner's and Àkos Östör's Making of Forest of Bliss (2002) is a combination book and DVD that contains eight teaching tools for better understanding Gardner's celebrated film Forest of Bliss. After the film was shot in 1985, filmmaker Gardner and anthropologist Östör recorded a conversation about each image and sound of the film while they screened it again in 1987, and remembered their filmmaking process on location in Benares, India. The feature length (89 minute) documentary about death ritual, reincarnation, the sacred Ganges River, and the very atmosphere of Benares is included as DVD, as are teaching tools such as frame grabs (still images from the film), a mathematically precise shot list, bibliography, important criticism and essays about the film, and the featured in-depth conversation between filmmaker Gardner and anthropological advisor Östör. This essay articulates the unique breakthroughs in pedagogy, cross-cultural studies, and multidisciplinary analysis such hybrid technology provides.     

磷脂DMPC Langmuir－Blodgett膜晶格结构的原子力显微镜研究

用原子力显微镜（ＡＦＭ）研究了磷脂ＤＭＰＣ三层Ｌａｎｇｍｕｉｒ－Ｂｌｏｄｇｅｔｔ（ＬＢ）膜的分子排列结构,结果表明：在磷脂ＬＢ膜的两相（液体压缩相Ｌｉｑｕｉｄ－ｃｏｎｄｅｎｓｅｄｐｈａｓｅ和液体扩张相Ｌｉｑｕｉｄ－ｅｘｐａｎｄｅｄｐｈａｓｅ）共存时,液体压缩相中的磷脂分子排列紧密,取向一致,分子间作用力较大,因而能够得到分子图像。而液体扩张相中的磷脂分子排列松散,取向混乱。分子间的作用力较弱,难于得到分子图像。在液体压缩相中磷脂分子以单斜晶格结构排列,分子间隔为０．７２ｎｍ．分子高度为２．１ｎｍ。这一结果和ＤＭＰＣ的单晶结构进行了比较。     

Atypical surface behavior of ceramides with nonhydroxy and 2-hydroxy very long-chain (C28–C32) PUFAs

Unique species of ceramide (Cer) with very-long-chain polyunsaturated fatty acid (VLCPUFA), mainly 28–32 carbon atoms, 4–5 double bonds, in nonhydroxy and 2-hydroxy forms (n-V Cer and h-V Cer, respectively), are generated in rat spermatozoa from the corresponding sphingomyelins during the acrosomal reaction. The aim of this study was to determine the properties of these sperm-distinctive ceramides in Langmuir monolayers. Individual Cer species were isolated by HPLC and subjected to analysis of surface pressure, surface potential, and Brewster angle microscopy (BAM) as a function of molecular packing. In comparison with known species of Cer, n-V Cer and h-V Cer species showed much larger mean molecular areas and increased molecular dipole moments in liquid expanded phases, which suggest bending and partial hydration of the double bonded portion of the VLCPUFA. The presence of the 2-hydoxyl group induced a closer molecular packing in h-V Cer than in their chain-matched n-V Cer. In addition, all these Cer species showed liquid-expanded to liquid-condensed transitions at room temperature. Existence of domain segregation was confirmed by BAM. Additionally, thermodynamic analysis suggests a phase transition close to the physiological temperature for VLCPUFA-Cers if organized as bulk dispersions.     

Effects of a kaolin-based particle film on oviposition and feeding of gypsy moth (Lep., Lymantriidae) and forest tent caterpillar (Lep., Lasiocampidae) in the laboratory

Abstract:  In the laboratory we investigated a kaolin-based crop protectant, Surround^® WP, that was mixed in a spray carrier (94% water, 2% methanol, 4% Triton X100) and applied as particle film against gypsy moth Lymantria dispar (L.) and forest tent caterpillar Malacosoma disstria Hubner. Paired-choice feeding tests showed that gypsy moth larvae were significantly (P < 0.05) less disposed to feed on red oak Quercus rubrus L. treated with high concentrations (60 and 120 g/l carrier) of kaolin than on untreated foliage. There was no significant difference (P > 0.05) between gypsy moth's consumption of kaolin-treated and untreated red oak when given a single food choice, but the adults were less inclined to oviposit on the kaolin-treated surfaces than on controls. However, no kaolin treatment completely deterred gypsy moth feeding or oviposition. Kaolin particle film did not influence forest tent caterpillar feeding and there were insufficient data to evaluate the effect of kaolin on the species' oviposition. The spray carrier did not increase the efficacy of the kaolin, but as an independent, albeit impractical treatment it constrained feeding by both insect species but did not affect gypsy moth oviposition. These initial laboratory findings suggest that applying kaolin-based particle film to forests would present significant challenges; but if these could be surmounted, the technique might assist in the management of gypsy moth but not likely in that of forest tent caterpillar.     

聚赖氨酸修饰丝素蛋白膜对神经干细胞生长和分化的影响

利用聚赖氨酸修饰丝素蛋白膜,观察其对神经干细胞(NSCs)生长及分化的影响,为中枢神经系统损伤修复材料的选择提供实验基础和理论依据。文中首先制备聚赖氨酸修饰的丝素蛋白膜,并通过核磁共振图谱和紫外-可见光谱进行验证。NSCs分别接种在单纯丝蛋白膜(Silk)、聚赖氨酸修饰的丝蛋白膜(Silk-PIL)和多聚赖氨酸(PLL)上进行培养,分别在1、3、5、7 d时用CCK-8检测NSCs增殖活性。在第7天时,用免疫荧光染色检测NSCs分化情况,Western blotting和TUNEL检测细胞凋亡水平,Real-time PCR检测脑源性神经营养因子(BDNF)mRNA水平。结果表明,核磁共振图谱和紫外-可见光谱证明聚赖氨酸成功地接枝到了丝素蛋白膜上,CCK-8检测显示:从第3天开始一直到第7天,NSCs在Silk-PIL上的增殖活性要显著高于Silk组(P0.05),而与PLL组无显著性差异(P0.05)。免疫荧光观察显示,NSCs在Silk-PIL上分化成神经元的细胞显著多于Silk组(P0.05),而与PLL组无显著性差异,3个组之间分化为星型胶质细胞的数量并无显著性差异。Western blotting和TUNEL检测结果表明Silk-PIL组NSCs凋亡程度显著小于Silk组(P0.05),但与PLL组无显著性差异(P0.05)。RT-PCR结果显示,NSCs在Silk-PIL和PLL组的BDNFmRNA表达水平显著高于Silk组(P0.05)。结果表明,聚赖氨酸修饰的丝素蛋白膜能够促进NSCs的增殖活性并减少NSCs细胞凋亡,同时促进NSCs向神经元方向分化,有望成为新型组织工程支架材料搭载NSCs移植修复中枢神经系统损伤。     

越冬期间香蕉果穗套袋的防寒效果及其对产量的影响

冬季香蕉果穗用兰色聚乙烯薄膜套袋之后,可提高袋内温度1～5℃,果实低温伤害卑只有1％左右,而未经套袋的达23％～35％,果指长度和径围增加率分别达12％和9％左右,果实产量比对照增加8％～16％。试验结果表明,兰色聚乙烯薄膜套袋是越冬期间香蕉防寒保果和增产的一项有效措施。     

A rapid method for determination of Proteus vulgaris with a piezoelectric quartz crystal sensor coated with a thin liquid film

A rapid method for microorganism detection using a piezoelectric quartz crystal sensor (PQC) coated with a thin liquid culture medium film was developed and applied to detect the cell number of Proteus vulgaris. This method employed the viscosity and density response of PQC and utilized the coagulation of gelatine medium solution in which the microorganisms had grown to determine the microorganism indirectly. Three time points (TT₁, DT, TT₂) were obtained from the coagulation curve and were found to be in good linear relationship with the logarithm of the initial number of P. vulgaris in the range 1·3 × 10²−1·3 × 10⁵ cells/ml. The detection was rapid and accurate because the coagulation of the thin liquid culture medium film was quick and the time points in the response curve were sharp and so were easy to determine accurately. The detection time was less than 4 h and only a micro sample was needed. A 5 h preincubation was needed before detection. Some experimental conditions are discussed in detail.