Short term essential fatty acid deficiency in rats. Influence of dietary carbohydrates

The effects of long term (8–14 wk) essential fatty acid (EFA)-deprived diets in rats are well documented. In the present study, we compared, in weanling rats, the effect of a short term (two wk) hydrogenated coconut oil, EFA-deprived, diet (D) with that of a corn oil, EFA-adequate, diet (A), using either sucrose (SU) or starch (ST) as carbohydrate. After two wk, rats fed the sucrose/hydrogenated coconut oil diet developed some characteristic features of EFA deprivation: slower growth rate, decreases in linoleic and arachidonic acid of plasma phospholipids and an increase in n−9 eicosatrienoic acid of plasma phospholipids. When rats ate the starch/hydrogenated coconut oil diet, there was a similar decrease in linoleic acid of plasma phospholipids, but only a small effect on growth rate and no change in the arachidonic acid content of plasma phospholipids. EFA deprivation and sucrose had opposite effects on plasma triglyceride (TG) levels: deprivation induced a decrease, whereas the sucrose induced an increase in very low density lipoprotein (VLDL) triglycerides. The observed decrease in plasma triglyceride during EFA deporivation might result from an activation of lipoprotein lipase during the early stages of deprivation.     

The behavior and derivatizations of carbohydrates in hydrogen fluoride

Low molecular weight β, 1 → 4-glucans (cellodextrins) are favorably prepared by cleavage of cellulose in liquid hydrogen fluoride at temperatures between ?15 and ?30°C. This is due to the suppression of the reversion reaction in that low temperature range. Under conditions favorable for reversion the presence of water leads to a competing hydrolysis and lower the average degree of polycondensation. For the preparation of defined O-glycosides from glucose and alcohols, hydrogen fluoride is not suitable as a reaction medium. Under reversion conditions, monohydroxy compounds are inferior in their reactivity to the competing carbohydrate molecules, and polyols like sorbitol furnish mixtures of isomeric glycosides. Gaseous hydrogen fluoride represents a highly suitable agent for the degradation of carbohydrate and lignin containing biomass, such as waste wood, for the purpose of providing fermentation raw material. As a model, lignocellulose was studied and the heat of reaction of the hydrogen fluoride sorption and desorption processes were examined. The practically important desorption value was found to be approximately 870 kJ/kg HF.     

PET生产常规化操作的重要性

介绍了辽阳石化公司聚酯厂所采取的常规化操作措施和取得的效果。它有效降低了生产过程中的突发事故产生的频率,保障了生产的平稳性和连续性,其中每一具体的措施都可以预防或减轻某一化工单元发生故障的可能性。常规化操作体现了生产的受控管理这一理念。     

塑料在信息时代扮演的重要角色

论述了塑料在现代通讯和信息技术应用领域起着越来越重要的作用，具有电导体，半导体，发光特性等更多新功能的塑料材料，可用于生产发光二极管，微处理器等电子部件产品。     

Microbial fuel cells utilising carbohydrates

The paper reports results of a mediatorless microbial fuel cell (MFC), utilising waste carbohydrate (manure) as a fuel, which did not use a catalyst or a proton exchange membrane and is thus environmentally friendly (by using no toxic substances) in treating waste. The cell used a manure sludge in the anode compartment and an aqueous salt solution (seawater) containing dissolved oxygen. The influence of the geometric position of the anode and cathode, both made of carbon cloth, had a major effect on the fuel cell power performance. The maximum power density obtained with the cell was 4.21 mW m^?2. The paper also reports results of a mediated MFC using a yogurt bacteria and methylene blue as mediator. This cell produced a maximum power density of over 13 mW m^?2. This power output compares quite favourably with that achieved with the same cell using glucose as fuel with E. coli (peak power density of 180 mW m^?2). Copyright © 2007 Society of Chemical Industry     

Thermal degradation of 6-chloro carbohydrates

It has been shown that 6-chloro sugar derivatives are thermally less stable than the corresponding unsubstituted carbohydrates. When heated, they generate hydrogen chloride which catalyzes a series of heterolytic reactions including transglycosylation, dehydration, inter- and intramolecular etherification, and condensation. The latter products are ultimately carbonized through free-radical reactions producing large amounts of char.     

The effects of dietary gossypol on animals

The pathological effects of gossypol in animals and the effects of protein quality and quantity on its toxicity are described. The method used for the isolation of gossypol from the liver of gossypol-intoxicated pigs and its identification are presented. Wide distribution of gossypol in swine is shown by determining the free and bound gossypol in the various organs. The levels of iron necessary to overcome toxicity and to lower its accumulation in pigs were investigated. Effects of copper, zinc, manganese and iron, alone and in combination, on the gains and the accumulation of gossypol in the liver of rats were studied. Iron was definitely the most effective detoxifying agent. Paper No. 3173 of the Journal Series of the N.C. State Univ. Agr. Exp. Station.     

零线重复接地的重要性

在变压器中性点接地的三相四线制低压供电系统中,工作接地、重复接地、保护接零线网构成了完整的保护接零系统,缺一不可。在工作中发现某些单位早已安装完毕的低压配电点没有安装重复接地极,这种供电方式是不正确的。下面谈谈零线重复接地的重要性。 (1)在零线断线并有一相碰壳故障时,重复接     

The importance of fatty acids in glycaemic response

Most diets worldwide are composed of high carbohydrate foods. Their consumption is associated with a rapid rise in blood glucose. The potential role that the degree of saturation of fatty acids may have in glycaemic response forms the basis of this paper. The addition of butter, olive oil or grapeseed oil significantly reduced the glycaemic index of white bread (white bread GI = 71; bread + butter GI = 53, bread + grapeseed oil GI = 58; bread+ olive oil GI = 50. The addition of olive oil had the greatest impact on GI. Olive oil has been widely recommended for its impact on blood lipids and cholesterol. Olive oil's influence on glycaemic response spawns a new line of research that should examine the role of lipids in carbohydrate metabolism.     

The preparation of 5-chloromethylfurfuraldehyde from high fructose corn syrup and other carbohydrates

A 92–95% conversion of high fructose corn syrup (HFCS) or crystalline D -fructose to 5-chloromethylfurfuraldehyde (CMF) was achieved using 300 mol% of concentrated hydrochloric acid in chlorobenzene, under a nitrogen atmosphere, a reaction temperature of 75°C and a reaction time of 1–2 h. Constant high-speed stirring was essential for high yields and purity of CMF. Inferior yields of CMF were obtained from glucose and starch. Saccharine, phenyl sulphone and thiuronium derivatives were prepared and characterised. The use of surfactants did not improve the yields of CMF.