Infrared spectroscopy studies of the cyclic anhydride as the intermediate for the ester crosslinking of cotton cellulose by polycarboxylic acids. I. Identification of the cyclic anhydride intermediate

The mechanism of esterification of cotton cellulose by a polycarboxylic acid was investigated using Fourier transform infrared spectroscopy (FT-IR). The infrared spectroscopic data indicate that a polycarboxylic acid esterifies with cotton cellulose through the formation of an acid anhydride intermediate. A five-member cyclic anhydride intermediate was identified in the cotton fabric treated with poly(maleic acid). The five-member cyclic anhydride is a reactive intermediate and readily esterifies when reaction sites are available. We also found that those polycarboxylic acids, which form five-member cyclic anhydride intermediates, crosslink cotton cellulose more effectively than those polycarboxylic acids which form six-member cyclic anhydride intermediates. © 1993 John Wiley & Sons, Inc.     

Ellipticity of the Linearly Polarized He-Ne Laser Radiation Reflected by the Leaves of Plants

The phenomenon of elliptical polarization of the linearly polarized radiation reflected near the Brewster angle by the leaves of plants has been investigated. It has been shown that the appearance of ellipticity is associated with the complex structure of the cuticle.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 2, pp. 236–240, March–April, 2005.     

Effect of Extensin - Like Cotton Proteins on Eukaryotic Cell Gene

The effect of extensin-like cotton proteins (ELP) on animal cell gene (KML cell culture) was studied. Cells perish (50%) at protein dose 100 g/mL (cytotoxic effect). DNA fragmentation is not observed. Cell death from ELP is hypothesized to occur via necrosis resulting from destruction of intracellular biochemical processes     

Synthesis and properties of fluorescent cotton cellulose labeled with norfloxacin

To expand the application of cellulose in the field of fluorescence techniques, the cotton cellulose was labeled with norfloxacin (Cell-NF) via a three-step reaction, involving alkali treatment, epoxy activation, and opening of the epoxy rings with norfloxacin molecules. And the coordination complexes of Cell-NF with rare earth ions terbium (Cell-NF-Tb) and europium (Cell-NF-Eu) were obtained. The products were detected by IR, TG, XPS, UV and fluorescence spectra. Results showed that the norfloxacin content of the labeled cellulose was about 6.73 w% and the start temperature of decomposition of the Cell-NF was raised by 40°C compared with the stock cotton cellulose. When excited at 340 nm, the Cell-NF, Cell-NF-Tb, and Cell-NF-Eu in the solid state could emit violet (430 nm), green (549 nm) and red (620 nm) light, respectively.     

Preparation and characterization of a novel green tea essential oil nanoemulsion and its antifungal mechanism of action against Magnaporthae oryzae

Blast is one of the most devastating fungal diseases of rice caused by Magnaporthe oryzae. Plant essential oil (EO) can function as antifungal agents and are regarded as a safe and acceptable method for plant disease control. However, EOs are unstable and hydrophobic, which limits its use. In the present study, we aimed for the preparation and characterization of a nanoemulsion (NE) from green tea essential oil (GTO) by ultrasonication method and determined the antifungal activity of NE on M. oryzae. The particle size and zeta potential of the NE were 86.98 nm and −15.1 mV, respectively. The chemical composition and functional groups of GTO and NE were studied by using GC–MS analysis, portable Raman spectroscopy, and FTIR coupled with chemometric analysis. GC–MS analysis showed the major components in GTO and NE were n-Hexyl cinnamaldehyde and L-α-Terpineol. Both GTO and NE showed good antioxidant activity and total phenol content. Moreover, the NE showed good antifungal activity against M. oryzae which was further confirmed by scanning electron microscopy (SEM) examination. Also, confocal Raman micro-spectroscopy (CRM) revealed the antifungal mechanism of GTO and NE on M. oryzae which proves the cell damage. To the best of our knowledge, this is the first study on the antifungal activity of GTO and NE against M. oryzae and also the use of CRM for the evaluation of the chemical changes in single fungal hyphae in a holistic approach. This study suggests that the prepared NE could be a potential candidate for use as a substitute for synthetic fungicides.     

超临界CO_2萃取桑叶总黄酮工艺的研究

采用超临界CO2萃取桑叶总黄酮,以得率为指标,对萃取压力、萃取温度、夹带剂乙醇的浓度和流量等影响因素进行正交试验。结果表明最佳工艺条件为:萃取压力35 MPa,温度55℃,乙醇质量分数90%,乙醇流量0.01 mL/min。此条件下桑叶总黄酮得率2.28%。该方法简便、可靠、选择性高,适于工业化生产。     

银杏叶中硒与多糖的季节分布

银杏叶中总硒和各种溶解形态硒含量随着季节而变化,实验研究了不同采摘期银杏叶中总硒及不同溶解态硒含量分布.7月、9月和霜降之后采摘的银杏叶总硒的含量分别为1.873,2.136,0.815 mg·kg-1,硒的形态以水溶态硒为主.银杏叶粗多糖含量分布依次为9月＞7月＞11月.7月份采集的银杏叶中得到粗多糖为棕褐色固体粉末...     

转基因棉花残体土壤降解特征的红外光谱研究

采用重铬酸钾容量法和红外光谱(FTIR)法分析了转基因抗虫棉花残体降解后的土壤腐殖质组分富里酸(FA)、胡敏酸(HA)和胡敏素(HM)的含量和结构特征.结果表明,棉花残体的降解使土壤各腐殖质组分含量增加,胡敏素的相对含量增加最大,胡敏酸次之,富里酸最小.与相应非转基因对照相比,转Bt基因棉花残体处理土壤各腐殖质组分含量...