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劳志华 《广东微量元素科学》2011,(9):31-31
元素科学、生命科学,关乎民生、关乎国运。元素医学、平衡医学,无病不防、无病不治。头发检测、活体检测,检测已病、检测未病。元素调理、食物调理,调理聪明、调理健康。
"先天不足"和"后天失调"的全球性"元素病",引起了各国政府的关注。中国政府出台了一系列法律文件,成立了国家级的相应机构进行调研和治理。与此同时,加大了元素科学和生命科学的教育和宣传力度, 相似文献
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劳志华 《广东微量元素科学》2011,(5):20-20
“先天不足”和“后天失调”的全球性“元素病”,引起了各国政府的关注。中国政府出台了一系列法律文件,成立了国家级的相应机构进行调研和治理。与此同时,加大了元素科学和生命科学的教育和宣传力度,取得可喜的成绩,控制了“碘缺乏病”和“硒缺乏病”,儿童锌缺乏率和儿童铅超标率下降。为了减少各种慢性病的发病率,卫生部、国家计委、教育部、科技部、民政部、财政部、农业部、贸易部、国务院扶贫办公室、轻工总会、全国妇联等11个部委联合制订了《中国营养改善行动计划》, 相似文献
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光化学比色传感器阵列以其价格低廉、方法简单、响应快速、信息量大等优点,得到了日益广泛的应用。本文主要介绍了光化学比色传感器阵列的研究进展,概括了近年来其在气体、生物样品、离子和小分子,以及混合物检测方面的应用,针对其不同原理及性能展开了讨论,并展望了其研究和应用前景。 相似文献
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浮选-原子吸收光谱法的研究 总被引:2,自引:0,他引:2
本文研究了浮选技术与原子吸收光谱测定相结合的新方法,灵敏度高、选择性好可连续测定多种痕量元素,操作简便快速。建立了M-SCN-RB、M-I-MB、M-I-MV、M-Br-RB萃取浮选和M-SCN-CPC泡沫浮选体系,直接用火焰原子吸收法测定。研究了金属离子在上述各体系中的浮选行为和分析特性,讨论了测定灵敏度,选择性和竞争浮选的问题。已用于测定水中ppb级Cd、Ag、Au、Pb、Cu、Bi和矿物中Au、Ag、Cd、Pb、Cu、Bi,分析结果与标准值相吻合。 相似文献
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劳志华 《广东微量元素科学》2011,(10):25-25
“先天不足”和“后天失调”的全球性“元素病”,引起了各国政府的关注。中国政府出台了一系列法律文件,成立了国家级的相应机构进行调研和治理。与此同时,加大了元素科学和生命科学的教育和宣传力度,取得可喜的成绩,控制了“碘缺乏病”和“硒缺乏病”,儿童锌缺乏率和儿童铅超标率下降。为了减少各种慢性病的发病率,卫生部、国家计委、教育部、科技部、民政部、财政部、农业部、贸易部、国务院扶贫办公室、 相似文献
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用原子吸收光谱法测定延边地区317名65~108岁老人头发中锌、铜、铁、锰、镁含量,观察不同民族、性别、年龄老人这些元素的差异。结果表明:1.朝鲜旗发锌低于汉族,满族发铜低于汉族、朝鲜族,汉族发镁高于朝鲜族、满族,发铁、发锰在汉、朝、满民族之间无区别。2.汉族、朝鲜族男发锌高于女性,汉族女性发铜高于男性,发铁、发锰、发镁在性别之间无区别。3、90岁组朝鲜族发锰、发镁低于65岁、76岁组,朝鲜族发锌、发铜、发铁在65~108岁之间无统计学意义。 相似文献
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The accelerated growth of aquaculture has resulted in a series of harmful effects to human health. The widespread and unrestricted use of antibiotics in this industry, to prevent bacterial infections, leads to remaining amounts in the aquatic environment. This has resulted in the emergence of antibiotic-resistant bacteria in aquaculture environments, in the increase in antibiotic resistance in fish pathogens as well as in the transfer of these resistance determinants to human pathogens. Moreover, the use of large amounts of antibiotics may lead to the presence of residual antibiotics in fish tissue and fish products. Fluoroquinolones, tetracyclines, penicillins, sulphonamides and other antibiotics, exhibiting activity against both Gram-positive and Gram-negative bacteria, are widely used for the treatment and prevention of diseases in fish. An extended and comprehensive review on the recent analytical methodologies concerning antibiotic residues in fish reported in the literature is provided in the present article. Emphasis is given on sample preparation regarding isolation and purification, chromatographic conditions and method validation according to legislation. Results of published assays are comparatively presented and criticised. 相似文献
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Hiroshi Hasegawa 《应用有机金属化学》1997,11(4):305-311
Seasonal changes in the distribution of arsenic species were observed in a dredged area in the southern basin of Lake Biwa, Japan. The concentrations of dimethylarsenic acid [DMAA(V)] became comparable with those of inorganic forms during a stratification period. DMAA(V) increased not only in the photic zone but also in the hypolimnion. In the photic zone, an increase in DMAA(V) was observed with the yearly maximum of water temperature. In the hypolimnion, the seasonal changes in methylarsenicals differed from those in surface waters. DMAA(V) maxima appeared seasonally under sub-anoxic conditions and developed regionally at the redox boundary and above the sediment surface. The DMAA(V) concentrations increased in the initial period of oxygen depletion and just after the disappearance of anoxia, while they diminished in the anoxic hypolimnion by midsummer. The seasonal behavior of trivalent methylarsenicals, which are readily oxidized in oxic environments, was similar to that of DMAA(V). The total arsenic concentration in the surface layer rose to a maximum in late summer. Methylarsenicals did not increase in such a way that the total arsenic concentration increased during summer. © 1997 by John Wiley & Sons, Ltd. 相似文献
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Penicillins are the most frequently found antibiotic residues in milk, as they are commonly used for the treatment of bacterial infections in cows. In the present study, we introduce a method for the rapid detection of penicillin residues in raw milk based on the determination of glucose concentration in milk with a dual flow-through biosensor. The molar concentration of glucose in milk is typically over 500 times lower than the concentration of lactose and is highly dependent on the rate of lactose hydrolysis, which is catalyzed by β-galactosidase. Glucose concentrations in milk change with variation in the β-galactosidase activity. β-Galactosidase is an enzyme produced in the microbiota in milk and its activity is inhibited by benzylpenicillin. Spiking milk with benzylpenicillin lowers glucose concentrations in comparison to high-quality milk after short storage intervals. The presence of penicillin in the milk of treated animals resulted in decreased glucose concentrations in comparison with high-quality milk that contained no antibiotics. The glucose concentration in milk samples was followed by the system enabling the elimination of the effects of bacterial respiration in the output with reliable results in less than 1?min. 相似文献
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Lyubimov AV Carr SN Brown AP Art JJ Crowell JA Levine BS 《Journal of photochemistry and photobiology. B, Biology》2005,80(3):225-234
The knowledge of intracellular spatial distribution of pH in prostates in animal models reflective of human prostate may have implications for drug development upon pH dependent drug delivery and activity. Freshly dissected prostate tissues (in vitro) or the entire prostate gland (in vivo) were loaded with fluorescent dyes and viewed using confocal microscopy. Images were initially taken in tissues perfused with RPMI-1640 medium. Calibration in situ was performed with high potassium buffers of known pH containing nigericin. Acetoxymethyl ester carboxy-SNARF-1 was visible in epithelial cells (but not stroma) in rat and dog prostates. The pH of lysosomes in prostate epithelial cells was 5.2 as determined by fluorescence of Lyso Sensor Green DND-189. A method of in situ confirmation of tissue viability was developed by a secondary loading and visualization of the BCECF fluorescent dye. Besides the direct measurement of the pH in rat and dog tissues (pH ≈ 7.0), a method of pH measurement in prostate tissue (rather than in cell culture) was developed. 相似文献
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Calibration methods for microdialysis sampling were studied in the muscle and adipose tissue of rats. Both the delivery method and the no-net-flux method were used to determine the extraction efficiency (EE) of acetaminophen and caffeine in both tissues. There was no concentration dependence of the EE either in vitro or in vivo for either acetaminophen or caffeine. The EEs determined by the delivery and no-net-flux methods were not different. However, the EEs of both caffeine and acetaminophen determined in vitro were significantly higher than those determined in the muscle and adipose. This indicates that mass transfer in the tissue is the rate-determining factor for the EE in vivo. The relative difference between the EE in vitro and the EE in the muscle was smaller than the difference between the EE in vitro and the EE in the adipose. In addition, the EE in the muscle decreased more than the EE in the adipose after the animal was euthanized. This indicated that exchange between the extracellular fluid and plasma is the rate-determining step in mass transport relative to microdialysis sampling. This has a more significant effect on the EE in the muscle than the EE in the adipose. Both the delivery and no-net-flux methods can be used to calibrate microdialysis probes in the muscle and adipose. 相似文献
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C. Albelda Y. Pico J. C. Molto G. Font J. Mañtes 《International journal of environmental analytical chemistry》2013,93(1-4):315-326
Abstract The accumulation, persistence and fate of systemic pesticide aldicarb was melencholy evaluated in orange crops. The concentration of this pesticide and its two toxic metabolites, aldicarb sulfoxide and aldicarb sulfone was determined in leaves, rind and pulp of three orange varieties (Satsuma, Navelina and Clemetina de Nules) and in the top soil of the orange groves. The groves were located in two different places in the Valencia Community (Spain). The analysis showed that the aldicarb concentration was lower than those of aldicarb sulfoxide and aldicarb sulfone. In all cases, the residues persisted at least 160 days in vegetable samples and between 157 and 227 days in soil samples. Residue concentrations measured in the soil samples were highly variable but a relation with the organic matter content can be observed. The residue levels found in vegetal products were higher in leaves than in rind, and in rind than in pulp. The maximum residue values were obtained between 47 and 70 days after the application. One hundred days after treatment (Security period) the residue levels of total fruit were lower than the maximum residue level of 0.2 mg/kg established by law. 相似文献
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辛厚文 《化学物理学报(中文版)》2000,13(4):388-405
化学体系中随机共振现象的特性、机理、本质和应用的研究是非常重要的前沿课题。综述中国科学技术大学非线性化学实验室,在化学体系随机共振现象的理论研究中,所取得的主要成果,并阐述化学体系随机共振现象研究中所提出来的若干重要问题:非均相化学体系中随机共振;化学体系中内信号随机共振;化学体系中多重随机共振;化学体系中随机共振的调制;化学体系中色噪声作用下的随机共振;化学体系中时空随机共振;耦合化学体系中随机共振;化学体系中双参量随机共振。 相似文献
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Effect of plasticizer concentration on the hysteresis,tear strength and stress-relaxation characteristics of black-loaded rubber vulcanizate 总被引:1,自引:0,他引:1
N. K. Dutta 《Colloid and polymer science》1991,269(4):331-342
The effect of plasticizer concentration on the stress softening, tear strength and stress relaxation of black loaded bromobutyl rubber vulcanizate has been investigated. The stress softening in the rubber vulcanizate, an energy dissipative process at higher strain, may be explained primarily by changes that take place in the rubber phase of the filled vulcanizate. Increased plasticizer concentration leads to decrease in the equilibrium hysteresis. A quantitative relationship between energy density and hysteresis has been derived, which is applicable at and below the elongation at break. Increase in plasticizer concentration results in decrease in the effective diameter of the tip of the tear, which in turn decreases the tear strength. Rate of relaxation decreases with increase in the plasticizer concentration in the carbon-black-filled vulcanizate. 相似文献