脂质与健脑

脂质是人类的基本营养物质之一,是最重要的健脑营养素。本文介绍了脑的发育特点与脂代谢的关系;脂质的结构和分类,以及脂质的健脑益智作用。旨在正确认识脂类,科学摄取脂类,提高智力,促进素质教育。     

超高效合相色谱法定性与定量分析补肾健脑颗粒

用超高效合相色谱法(Ultra performance convergence chromatography,UPC2)建立补肾健脑颗粒及各药材提取物的指纹图谱,对补肾健脑颗粒主要色谱峰进行归属分析,并测定有效成分β-蜕皮甾酮和松果菊苷的含量。样品经乙醇提取后,进样1μL,用Waters ACQUITY UPC2TMBEH柱(100 mm×3.0 mm,1.7μm)分离,柱温为40℃,以超临界CO2-0.05%H3PO4-甲醇溶液为流动相,梯度洗脱,流速为0.8 m L/min。分析补肾健脑颗粒和各药材提取物的UPC2指纹图谱,利用各峰相对保留时间、紫外光谱图及部分对照品归属主峰。结果表明,补肾健脑颗粒UPC2指纹图谱中15个主峰来源明确,其中12号峰为β-蜕皮甾酮,含量为380μg/g,15号峰为松果菊苷,含量为9.562 mg/g。与HPLC和UPLC法相比,本方法简便、快速,精密度高,重现性好。     

喷洒植物营养素后稻米、蔬菜、水果中几种微量元素的测定

对施用新型“农药”——植物营养素后几种不同农作物的前处理方法进行了研究,提出了操怍简便、精密、准确的测定方法,为在我国建立评价施药后农作物中微量元素变化水平提供了可靠的测试手段。并通过对施药前后,农作物中锌、铜、铁三种微量元素含量的测定和比较,为植物营养素类“农药”的卫生鉴定提供了新的指标。     

食物中的营养素的教学设计——糖类维生素的教学案例

1 学生学情分析和教学资源的处理 北京市第五十中学高二(一)班为实验班,在2007年5月学完人教版高二化学第七章糖类油脂蛋白质以后,在糖类的主要化学性质方面有一定的基础,可以在此基础上加以拔高,学习淀粉的消化过程、生理作用、在人体中生理转化过程中所表现出的部分化学性质以及代谢过程中的某些生化反应.同时补充学习维生素的相关知识.     

人体必需的营养物质——肉毒碱

肉毒碱被发现百余年来,科学界对其研究经久不衰,含有肉毒碱的药品、营养品倍受消费者青睐.介绍了L-(-)-肉毒碱的来源、生物学功能、合成与应用.     

试纸检测食物有害残留 几分钟出结果

可视化快速检测试纸的问世突破了制约食品安全监管能力的技术瓶颈,降低了检测成本,使监管从事后处理变为现场反应。     

营养素与亚临床铅中毒的防治

营养素能有效防治亚临床铅中毒,阐述了钙、铁、锌、硒及维生素等营养素与铅毒性作用的相互关系。     

几种常见饮用水简介

水是生命之源,人体中水的含量约占65%,细胞中许多生化反应都要在水环境下进行,水对人体的重要性不言而喻。随着人们生活水平的不断提高,保健意识的逐步增强,饮用矿泉水、矿物质水、纯净水、功能水等种类的水走进了人们的视野,对于商家的炒作我们要做到理性消费。了解这些水的化学成分、物化性质、制备工序及功能用途很有必要。     

实验室常用的几种干燥剂

干燥剂是实验室常需应用的。但是在不同的场合与不同的要求下,需要有选择地使用。现在将实验室常用的几种干燥剂的性质与性能介绍于后,另外对硅胶与过氯酸镁的装备也作一简要介绍。1.氯化钙:CaCl_2·6H_2O 为无色结晶,加热失去4H_2O 而变为白色多孔的二水化合物 CaCl_2·2H_2O,再赤热时,完全失去结晶水而变为白色结晶 CaCl_2。由于CaCl_2常含有 CaO,因此具硷性反应。CaCl_2易溶于水并放出大量热。它具有强的吸湿性,常温时它上面的     

求取反应速度的几种数学方法

对于均相与非均相反应动力学研究一般根据不同反应类型与条件选择不同的反应器,而对不同的反应器,求取反应速度的数学方法也不同。例如,选用连续搅拌的恒容反应器、循环反应器(包括内循环和外循环反应器)或微分反应器时,这种类型的反应器可视为反应器内各     

人体中影响心理健康的一些内源性化学物质

好斗、逃学等不良行为的产生不但是一种心理的作用,而且还与人体内的一些化学物质有关.一些内源性化学物质在人体中含量的多少对人的心理健康有直接的影响,例如:钙可使人镇静;镁能减轻心理压力;锌与记忆和智力有关;多巴胺能使人产生快感等.     

Synthesis and Some Characteristics of Magnetic Matrices for Fixation of Biologically Active Substances

A possibility of production of nonporous magnetic matrices with two-layer coating based on cobalt ferrite with the aim to use these matrices for fixation of biologically active substances was considered. The function of the first layer (silica coating) is to shield the cobalt ferrite surface and provide conditions for applying the second (polymer) layer containing various functional groups.     

A Study of the Retention Behavior of Some Basic Drug Substances by Ion-Pair HPLC

Abstract

Ion-pair HPLC of some basic drugs using alkane sulfonic acid as counter ion is described. Various ways to manipulate the retention of the compounds are discussed.     

Peculiarities of Adsorption of Some Polar Substances from Vapor Phase on a Microporous Clay Adsorbent

The adsorption of polar organic substances (methanol, pyridine, and acetonitrile) and water was studied from the vapor phase on microporous adsorbent prepared by the substitution of polyhydroxyaluminum ions for the sodium ions of natural montmorillonite clay. The differential isosteric heats of adsorption of these substances were calculated and analyzed in a wide range of fillings.     

高效液相色谱法检测食品中多种香料共存时的罂粟壳

 采用高效液相色谱法检测食品中多种香料共存时的罂粟壳。样品经碱化后采用氯仿 乙醇 (体积比为 9∶1)提取 ,在苯基柱上以乙腈 甲醇 水为流动相进行分离 ,外标法定量。罂粟碱 ,吗啡 ,可待因在 1 2mg/L～ 10 0mg/L范围内线性关系良好 ,平均回收率为 79.3%～ 86 .1%。该方法的专属性和准确度较高。     

Some Anomalies in Coadsorption of Two Organic Substances Due to Differences in Molecular Interaction of Species Undergoing Coadsorption

Effect of molecular interaction between species undergoing coadsorption on the potential dependences of coverages ₁and ₂, surface tension, and equilibrium and nonequilibrium differential capacitances is analyzed on the basis of a set of isotherms for coadsorption of components 1 and 2 within a common monolayer when the EDL inner part obeys a model of three parallel capacitors. It is shown that, in a certain potential interval, at a certain ratio between adsorption parameters, the set of isotherms may have solutions that correspond to a minimum in a free energy surface, which is a function of ₁and ₂.     

Prediction of Critical Temperatures and Critical Pressures of Some Industrially Relevant Organic Substances from Rather Simple Topological Descriptors

The simplest topological molecular parameters were applied to predict critical temperatures and critical pressures in terms of the QSAR/QSPR theory. Through the development of four different calculation schemes, the convenience of using the atomic coordination numbers for different atoms and the corresponding identity of chemical bonds was shown. A satisfactory agreement between the theoretical and experimental data was attained. Some limitations of the proposed approach are pointed out.     

Strengthening Aqueous Electrolytes without Strengthening Water

Aqueous electrolytes typically suffer from poor electrochemical stability; however, eutectic aqueous solutions—25 wt.% LiCl and 62 wt.% H₃PO₄—cooled to −78 °C exhibit a significantly widened stability window. Integrated experimental and simulation results reveal that, upon cooling, Li⁺ ions become less hydrated and pair up with Cl⁻, ice-like water clusters form, and H⋅⋅⋅Cl⁻ bonding strengthens. Surprisingly, this low-temperature solvation structure does not strengthen water molecules’ O−H bond, bucking the conventional wisdom that increasing water's stability requires stiffening the O−H covalent bond. We propose a more general mechanism for water's low temperature inertness in the electrolyte: less favorable solvation of OH⁻ and H⁺, the byproducts of hydrogen and oxygen evolution reactions. To showcase this stability, we demonstrate an aqueous Li-ion battery using LiMn₂O₄ cathode and CuSe anode with a high energy density of 109 Wh/kg. These results highlight the potential of aqueous batteries for polar and extraterrestrial missions.     

The Crystalline State of Macromolecular Substances

Unlike low molecular weight substances, high polymers do not crystallize completely. However long the crystallization process is continued, they still consist of a mixture of crystalline and non crystalline regions. In the undrawn material, these regions form larger units which are known as spherulites. Questions that are of special interest concern the arrangement of the chains in the noncrystalline regions, the causes of chain folding, and the imperfections in the crystals. The incomplete crystallization is a consequence of kinetic inhibitions. This can be deduced from the fact that the crystalline fraction increases with rising crystallization temperature. If polymerization is carried out in the solid crystalline state, one obtains a completely crystalline polymeric material.