搜索到77254篇“ FRACTIONS“的相关文章
Determination of Carbon and Nitrogen Isotope Fractions in Asparagine, Aspartic Acid, Threonine and Methionine
2024年
The nomenclature for compounds that are modified with isotopes is growing every day. Compounds can be modified with isotopes either individually, in a functional group or groups, or completely with all atomic centers of the element. This diversity of isotope-modified compounds increases the range of researches that can be studied using them. Compounds modified with isotopes of carbon-13 or nitrogen-15 can be converted into carbon monoxide, carbon dioxide and molecular nitrogen. Currently, only the average value of carbon-13 or nitrogen-15 isotopes can be determined. However, by directly determining the atomic share of these isotopes in organic compounds modified with isotopes, information about the isotopic centers of the element can be obtained. The atomic fraction of an element is defined as a single carbon or nitrogen isotope-modified center or centers, or all centers that are isotope-modified with that element at the same time. Carbon-13 or nitrogen-15 isotopes’ atomic fraction can be determined molecularly or with fragment ions of different elemental content, or both. This makes the method self-verifying, increasing the accuracy and reliability of the results obtained. Amino acids, such as asparagine, aspartic acid, methionine, and threonine, are essential for the human body. This proposed method of isotopic analysis will increase the possibilities for scientific research using these compounds.
Lamzira PharulavaLevani EliashviliVakhtang BetlemidzeBachana Sulava
关键词:ASPARAGINETHREONINEMETHIONINE
Effect of metal fractions on rice grain metal uptake and biological parameters in mica mines waste contaminated soils
2024年
Heavy metals from mica waste not only deteriorate the soil quality but also results in the uptake of metals in the crop.The present investigation was conducted to evaluate the effects of different fractions of metals on the uptake in rice,soil microbial and biochemical properties in mica waste-contaminated soils of Jharkhand,India.From each active mine,soil samples were randomly collected at distances of<50 m(zone 1),50–100 m(zone 2),and>100 m(zone 3).Sequential metal extraction was used to determine the fractions of different metals(nickel(Ni),cadmium(Cd),chromium(Cr)and lead(Pb))including water-soluble(Ws)and exchangeable metals(Ex),carbonate-bound metals(CBD),Fe/Mn oxide(OXD)bound metals,organically bound metals(ORG),and residues(RS).The Ni,Cr,Cd and Pb in rice grain were 0.83±0.41,0.41±0.19,0.21±0.14 and 0.17±0.08 mg/kg respectively.From the variable importance plot of the random forest(RF)algorithm,the Ws fraction of Ni,Cr and Cd and Ex fraction of Pb was the most important predictor for rice grain metal content.Further,the partial dependence plots(PDP)give us an insight into the role of the two most important metal fractions on rice grain metal content.The microbial and enzyme activity was significantly and negatively correlated with Ws and Ex metal fractions,indicating that water-soluble and exchangeable fractions exert a strong inhibitory effect on the soil microbiological parameters and enzyme activities.
Saibal GhoshSandip MondalJajati MandalAbhishek MukherjeePradip Bhattacharyya
Effects of long-term partial substitution of inorganic fertilizer with pig manure and/or straw on nitrogen fractions and microbiological properties in greenhouse vegetable soils
2024年
Partial substitution of inorganic fertilizers with organic amendments is an important agricultural management practice.An 11-year field experiment(22 cropping periods)was carried out to analyze the impacts of different partial substitution treatments on crop yields and the transformation of nitrogen fractions in greenhouse vegetable soil.Four treatments with equal N,P_(2)O_(5),and K_(2)O inputs were selected,including complete inorganic fertilizer N(CN),50%inorganic fertilizer N plus 50%pig manure N(CPN),50%inorganic fertilizer N plus 25%pig manure N and 25%corn straw N(CPSN),and 50%inorganic fertilizer N plus 50%corn straw N(CSN).Organic substitution treatments tended to increase crop yields since the 6th cropping period compared to the CN treatment.From the 8th to the 22nd cropping periods,the highest yields were observed in the CPSN treatment where yields were 7.5-11.1%greater than in CN treatment.After 11-year fertilization,compared to CN,organic substitution treatments significantly increased the concentrations of NO_(3)^(-)-N,NH_(4)^(+)-N,acid hydrolysis ammonium-N(AHAN),amino acid-N(AAN),amino sugar-N(ASN),and acid hydrolysis unknown-N(AHUN)in soil by 45.0-69.4,32.8-58.1,49.3-66.6,62.0-69.5,34.5-100.3,and 109.2-172.9%,respectively.Redundancy analysis indicated that soil C/N and OC concentration significantly affected the distribution of N fractions.The highest concentrations of NO_(3)^(-)-N,AHAN,AAN,AHUN were found in the CPSN treatment.Organic substitution treatments increased the activities ofβ-glucosidase,β-cellobiosidase,N-acetyl-glucosamidase,L-aminopeptidase,and phosphatase in the soil.Organic substitution treatments reduced vector length and increased vector angle,indicating alleviation of constraints of C and N on soil microorganisms.Organic substitution treatments increased the total concentrations of phospholipid fatty acids(PLFAs)in the soil by 109.9-205.3%,and increased the relative abundance of G^(+)bacteria and fungi taxa,but decreased the relative abundance of G-bacteria,total bacteria,and
Shuo YuanRuonan LiYinjie ZhangHao'an LuanJiwei TangLiying WangHongjie JiShaowen Huang
Determination of Carbon and Nitrogen Isotope Fractions in Tartaric Acid, Oxalic Acid, Glucose and Fructose—National Center of High Technologies of Georgia
2024年
Tartaric acid, oxalic acid, glucose, and fructose are highly important compounds. A comprehensive study of these substances is fascinating from a scientific perspective. They are key components found in wine, vegetables, and fruits. Understanding the isotopic compositions in organic compounds is crucial for comprehending various biochemical processes and the nature of substances present in different natural products. Tartaric acid, oxalic acid, glucose, and fructose are widely distributed compounds, including in vegetables and fruits. Tartaric acid plays a significant role in determining the quality and taste properties of wine, while oxalic acid is also prevalent but holds great interest for further research, especially in terms of carbon isotopic composition. We can unveil the mechanisms of processes that were previously impossible to study. Glucose and fructose are the most common monosaccharides in the hexose group, and both are found in fruits, with sweeter fruits containing higher amounts of these substances. In addition to fruits, wheat, barley, rye, onions, garlic, lentils, peppers, dried fruits, beans, broccoli, cabbage, tomatoes, and other foods are also rich sources of fructose and glucose. To determine the mass fraction of the carbon-13 isotope in these compounds, it is important to study their changes during natural synthesis. These compounds can be modified with a carbon center. According to the existing isotopic analysis method, these compounds are converted into carbon oxide or dioxide [1]. At this point, the average carbon content in the given compound is determined, but information about isotope-modified centers is lost. Dilution may occur through the transfer of other carbon-containing organic compounds in the sample or by dilution with natural carbon or carbon dioxide during the transfer process. This article discusses the possibility of carbon-13 isotope propagation directly in these compounds, both completely modified and modified with individual carbon centers. The literature provides infor
Lamzira PharulavaLevani EliashviliVakhtang BetlemidzeBachana Sulava
关键词:GLUCOSEFRUCTOSECARBON
The Njiki’s Fundamental Theorem-Definition on Fractions in the Mathematical Set ℚ and by Extension in ℝ and ℂ, for the Purpose of Leading to the Construction of Some Algebraic Structures as Its Theoretical Applications and for the Practical Ones
2024年
The purpose of the research in the NJIKI’s fundamental THEOREM-DEFINITION on fractions in the mathematical set ℚand by extension in ℝand ℂand in order to construct some algebraic structures is about the proved EXISTENCE and the DEFINITION by NJIKI of two INNOVATIVE, IMPORTANT and TEACHABLE operations of addition or additive operations, in ℚ, marked ⊕and +α,β, and taken as VECTORIAL, TRIANGULAR, of THREE or PROPORTIONAL operations and in order to make THEM not be different from the RATIONAL ONE, +, but to bring much more and new information on fractions, and, by extension in ℝand ℂ. And the very NJIKI’s fundamental THEOREM-DEFINITION having many APPLICATIONS in the everyday life of the HUMAN BEINGS and without talking about computer sciences, henceforth being supplied with very interesting new ALGORITHMS. And as for the work done in the research, it will be waiting for its extension to be done after publication and along with the research results concerned.
Jean Claude Njiki
水牛角含巯基类成分解热效应评价研究
2024年
目的制备水牛角含巯基类成分(-SH active fractions,SHF),评价其解热效应。方法通过十二烷基硫酸钠-二硫苏糖醇(SDS-DTT)联合提取法制备水牛角SHF,并采用Ellman法测定游离巯基(-SH)浓度;基于nano LC-MS/MS分析表征水牛角SHF物质组成。采用脂多糖(LPS)建立大鼠发热模型评价水牛角SHF解热活性,采用酶联免疫吸附法(ELISA)试剂盒测定血浆中前列腺素E 2(PGE 2)、白细胞介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)的水平,测定下丘脑环磷酸腺苷(cAMP)、PGE 2、TNF-α的水平;采用非靶向代谢组学的方法,探究水牛角SHF对发热大鼠血浆代谢物干预情况。结果SDS-DTT联合提取法可有效制备水牛角SHF,其中主要成分为含丰富半胱氨酸残基(Cysteine,Cys)的Ⅰ型、Ⅱ型角蛋白、角蛋白相关蛋白等,SHF的-SH占蛋白质比例较水牛角水提液提高了约20倍。发热大鼠给予水牛角SHF 0.5 h后大鼠体温显著下降(P<0.01),且解热效应持续4.5 h;同时显著降低血浆及下丘脑PGE 2、IL-1β、TNF-α、cAMP等水平。从空白组与模型组血浆样本中共鉴定出137个潜在差异代谢物,水牛角SHF可回调其中31个代谢物,包括溶血磷脂酸、磷脂酰肌醇、磷脂酸、甘油三酯、磷脂酰胆碱等,主要涉及甘油磷脂代谢通路。结论水牛角SHF解热效应确切,给药剂量为水提液的1/10即可显示与其相当的解热效应,为水牛角清热功效物质基础研究提供了方向和依据。
黄思莹冯旗园包旺林黄潇正武文星赵明段金廒刘睿
关键词:水牛角解热抗炎
石油馏分的碳分布和结构族组成实验方法改进
2024年
表征重质石油组分结构族组成的常用方法有3种:n-d-M法、密度法和改进的B-L法。改进的B-L法是分析重质油结构组成较理想的方法,但该方法基础数据分析需采用核磁共振等现代大型仪器设备,不适合在实验教学中应用。目前教学实验中用的n-d-M法适合沸点350~500℃的油品。密度法计算方便,通过测定M、%C、%H,适用于f_(A)范围在0.23~0.34的油品。为了让高校石油化工专业学生更好地掌握分析表征石油及馏分的手段,选用多种油品,将计算方法改为n-d-M法和密度法同时使用。
文萍袁存昱刘坤
关键词:石油馏分
小米各级蛋白组分对淀粉糊化特性的影响
2024年
根据溶解度的不同,将4种蛋白组分从小米全粉体系中逐步去除,利用扫描电镜(SEM)、低场核磁共振(LF-NMR)、傅里叶变换红外光谱、快速黏度分析仪(RVA)探究样品结构及糊化特性的变化,并构建蛋白组分-淀粉重组体系进行反向验证。结果表明:整体而言,醇溶蛋白对淀粉糊化特性的影响最为显著,其次为谷蛋白;清、球蛋白的影响程度较小。SEM结果显示,醇溶蛋白对复粒淀粉无连接、包裹作用,对淀粉糊化不构成物理屏障,而谷蛋白则明显包围连接了淀粉颗粒。结合蛋白组分特性及RVA、LF-NMR试验结果,可知醇溶蛋白的高疏水性引发了憎水效应,增加了体系内水分子移动性,促进淀粉颗粒吸水溶胀,提高淀粉各项糊化特性值;谷蛋白降低淀粉糊化的峰值黏度及崩解值,延长糊化峰值时间,限制糊化进程。
张凡付永霞曾鸣宋昊沈群
关键词:小米蛋白组分淀粉糊化特性
碳五馏分中二烯烃选择性加氢催化剂的研究进展
2024年
总结了用于不饱和烃选择性加氢催化剂的研究进展以及发展前景;重点介绍了近年来对于贵金属Pd基催化剂进行改性处理以提高产物选择性以及非贵金属等金属催化剂的优化策略;对二烯烃选择性加氢催化剂的制备策略进行了进一步的展望。
蔡璐郑艳霞李玉超左村村黄昊飞崔广军
关键词:碳五馏分催化剂载体NI基催化剂选择性加氢
Screening for Anti-tumor Activity of Fractions from Buddleja officinalis Maxim
2024年
[Objectives]The anti-tumor activity of fractions from Buddleja officinalis Maxim.by petroleum ether,ethyl acetate,n-butanol and water solvent was studied.[Methods]The ethanol extract from B.officinalis Maxim.was extracted and then concentrated with petroleum ether,ethyl acetate,n-butanol and water,respectively,and the extracts were obtained.The inhibitory effects of the four different fractions on the growth of three tumor cell lines in vitro were detected by CCK-8 method,and the median inhibitory concentration(IC 50 value)was calculated.[Results]The four fractions inhibited the growth of the three tumor cell lines in vitro,among which the n-butanol fraction had the best anti-tumor activity.The IC 50 values of the n-butanol fraction on human gastric cancer(SGC-7901),human breast cancer(MCF-7)and human liver cancer(BEL-7404)cell lines were 0.08,1.58 and 0.12 mg/mL,respectively.[Conclusions]Petroleum ether,ethyl acetate,n-butanol and water fractions from the ethanol extract of B.officinalis Maxim.had certain anti-tumor effects,and the n-butanol fraction had the best anti-tumor activity.
Tong LIXin XIELiyuan LIAipeng LIZhidong LEITingting HESirui MOShangfeng HUANGYao LINSuoyi HUANGLixiang LUShiyou ZHOU
关键词:ANTI-TUMOR

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