Iron, zinc, copper and magnesium nutritional status in Mexican children aged 1 to 11 years Estado nutricio de hierro, zinc, cobre y magnesio en niños mexicanos de 1 a 11 años de edad

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Ma. del Carmen Morales-Ruán

2012-04-01

Full Text Available OBJECTIVE: To describe the micronutrient nutritional status of a national sample of 1-11 year old Mexican children surveyed in 2006 in National Health and Nutrition Survey (ENSANUT 2006 and their association with dietary and sociodemographic factors. MATERIALS AND METHODS: Serum samples were used (n=5 060 to measure the concentrations of ferritin, transferrin receptor, zinc, copper and magnesium. RESULTS: Prevalence of deficiencies in 1-4 and 5-11y old children were for iron (using low ferritin 26.0 and 13.0%; zinc, 28.1 and 25.8%, respectively; and copper, ≈30% in both age groups. Magnesium low serum concentrations (MLSC, were found in 12.0% and 28.4% of the children, respectively. Being beneficiary of Liconsa (OR=0.32; C.I.95%, 0.17-0.61 or belonging to higher socioeconomic status (OR=0.63; C.I.95%, 0.41-0.97 were protective against iron deficiency. Increasing age (OR=0.59; C.I.95%, 1.19-1.32 and living in the Central Region (OR=0.59; C.I.95%, 0.36-0.97 were protective against MLSC. CONCLUSIONS: Deficiencies of iron and zinc are serious public health problems in Mexican children.OBJETIVO: Describir el estado nutricio de micronutrimentos en niños de 1-11 años de edad de la Encuesta Nacional de Salud y Nutrición 2006 y su asociación con factores dietéticos y sociodemográficos. MATERIAL Y MÉTODOS: Se usaron muestras séricas (n=5060 para medir las concentraciones de ferritina, receptor de transferrina, zinc, cobre y magnesio. RESULTADOS: La prevalencias de deficiencias en niños de 1-4 y de 5 a 11 años fueron para ferritina, 26.0 y 13%; zinc, 28.1 y 25.8% respectivamente y cobre ≈30% en ambos grupos. Las concentraciones bajas de magnesio (CBM fueron 12.0 y 28.4%, respectivamente. Ser beneficiario de Liconsa (RM=0.32; IC 95%: 0.17-0.61 y pertenecer al nivel socioeconómico alto (RM=0.63; IC, 95%: 0.41-0.97 fueron protectores para deficiencia de hierro. La edad (RM=1.26; IC, 95%: 1.19-1.32 y vivir en la región Centro (RM=0.59; IC, 95

Deterioro de aleaciones de cobre por acción humana

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Duran, A.

2008-02-01

Full Text Available Results are presented from several samples taken from leaves of the Pardon Portico of Mosque-Cathedral of Cordoba, where an alteration on their surface was detected. Metal samples analyzed using X-ray microanalysis and powder xray diffraction were predominantly constituted by copper with some amounts of zinc attributed to brass, whereas other samples were also constituted by copper, tin and lead attributed to bronze. Surface samples were analyzed using the same techniques. In addition Fourier transform infrared spectroscopy was also used.The main compound identified in all the surface of the leaves is copper chloride hydroxide (atacamite. Lead chlorides have also been found. These data show that the sudden alteration that appears may be attributed to the use of some cleaning product containing chloride. Other compounds detected in the surface were gypsum, quartz and oxalates coming from environmental contamination.

Se exponen los resultados de algunas muestras alteradas procedentes de la Puerta del Perdón, pertenecientes a la Mezquita de Córdoba. Algunas de las muestras de metal analizadas mediante difracción de rayos X y microanálisis por energía dispersiva de rayos X estaban constituidas por latón (cobre con pequeñas cantidades de zinc, mientras que otras estaban constituidas por bronce (cobre, estaño y plomo. La superficie de las muestras se analizó empleando las mismas técnicas. Asimismo, se usó espectroscopia de infrarrojos. El componente principal identificado en la superficie de la puerta es cloruro básico de cobre (atacamita. Además se han encontrado cloruros de plomo. Estos datos demuestran que la repentina alteración de la superficie se puede atribuir al uso de productos de limpieza con alto contenido en cloro. Otros compuestos procedentes de la contaminación externa, como yeso, cuarzo y oxalatos también se detectaron en la superficie.

Comparação dos teores de cobre e zinco em leguminosas cruas e após serem processadas termicamente em meio salino e aquoso Evaluation of total amount of copper and zinc by legumes raw and thermally processed ina an aqueous and saline medium

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E. C. B. Andrade

2004-09-01

Full Text Available O cobre e o zinco participam de diversas reações no organismo, diretamente ou como co-fatores de enzimas, e são considerados essenciais. Avaliar os teores destes, em leguminosas cruas e após processamento térmico, permite um conhecimento do comportamento destes metais em meio salino e aquoso o que auxiliará no conhecimento do aproveitamento destes pelo organismo humano. Amostras de feijões preto, branco, carioquinha, manteiga, mulatinho, ervilha, lentilha e grão-de-bico, duas marcas de cada tipo e em dois lotes, foram analisadas quanto ao teor total de cobre e zinco quando cruas e processadas termicamente em meio salino e aquoso. A abertura das amostras foi feita por calcinação a 550ºC. As amostras que foram processadas termicamente, passaram por dessecação em estufa a 105ºC antes da calcinação. O teor total de cobre e zinco nas amostras foi determinado através da espectrometria de absorção atômica em chama. Na análise da rejeição de resultados foram aplicados o teste Dixon e o teste t de Student. Observou-se que, após o processamento térmico em meio salino ou aquoso, a maioria das amostras não teve perda significativa dos teores de cobre e zinco em relação às amostras cruas. Considerando que os teores médios do cobre e zinco nas amostras cruas foram, respectivamente, de 0,75mg% e 3,2mg% ao ser consumido uma porção média de leguminosas, cerca de 50g, a mesma fornece aproximadamente 19% e 10% das necessidades diárias de cobre e zinco, respectivamente, para um homem adulto segundo a R.D.A.Copper and zinc are considered essential oligoelements to human nutrition, taking part in several reactions either directly or as enzymatic co-fators. The amount of these elements in legumes, both raw and thermally processed in an aqueous and saline medium, provides an insight into their behavior, thus allowing an understanding of how these metals are best utilized by the human body. Two different commercial samples of raw and

Estado nutricional, ferro, cobre e zinco em escolares de favelas da cidade de São Paulo Nutritional status, iron, copper, and zinc in school children of shantytowns of Sao Paulo

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Elisabete B. Santos

2007-08-01

Full Text Available OBJETIVO: Avaliar a antropometria, a composição corporal e o estado nutricional em ferro, cobre e zinco segundo o gênero, de crianças e adolescentes institucionalizados, moradores de duas favelas da cidade de São Paulo. MÉTODOS: Estudo transversal utilizando medidas de peso, estatura, circunferência braquial, dobras cutâneas, bioimpedância elétrica, os escores Z da relação estatura para idade, índice de massa corporal, área do braço, área muscular do braço e área de gordura do braço. Os percentuais de gordura corporal e massa magra foram analisados segundo fórmulas de Siri e Slaughter. Foram determinados hemoglobina, hematócrito, ferro, ferritina, cobre e zinco séricos. RESULTADOS: Foram maiores o peso corporal, circunferência do braço, dobras cutâneas do tríceps e subescapular, resistência elétrica, escores Z da área do braço, área muscular do braço e percentual de gordura corporal no sexo feminino em relação ao masculino. Baixa estatura foi encontrada em 8% das meninas e 5,6% dos meninos, sem diferença quanto ao gênero. Houve menor prevalência de desnutrição (2% das meninas e 5,6% nos meninos, do que de sobrepeso e obesidade (30% e 11,2%, respectivamente. Observou-se anemia em 24,4% e ferropenia em 10,5% dos escolares com ou sem anemia. Apresentaram valores abaixo do limite inferior do padrão de referência para cobre e zinco séricos, respectivamente três e sete indivíduos. CONCLUSÃO: Na população estudada, de baixo nível econômico e institucionalizada, ocorre o processo de transição nutricional e alta prevalência de anemia que não resulta da interação ferro, cobre e zinco.OBJECTIVE: To assess the anthropometry, body composition and iron, copper and zinc nutritional status, according to gender, of institutionalized children and adolescents living in two shantytowns in the city of Sao Paulo. METHODS: A cross sectional study using weight, height, arm circumference, skinfolds, electrical

Distribución de selenio, cobalto,molibdeno y cadmio en el proceso de fundición de cobre bajo recirculación de polvos

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Montenegro, V.

2008-06-01

Full Text Available Usually dust generated from copper smelting in Chile contains high concentrations of copper and arsenic, but also other metals of considerable value and some environmental interest such as selenium, cobalt and molybdenum. It is desirable to understand the behavior of those elements when the smelting process operates with dust recirculation. In this study, the effect of dust recirculation to smelting process on the distribution among the matte, slag and gas phases were evaluated as a function of matte grade, amount of recirculated dust, oxygen enrichment and temperature. Experimental results show that selenium can be concentrated at high matte grade ranges and high oxygen enrichments in blowing gas. However, the result suggested that high recirculation amounts to smelting process are not feasible because it increases the minor metal losses.

Usualmente, el polvo generado durante el proceso de fundición de cobre en Chile, contiene altos contenidos de cobre y arsénico, pero también otros metales de considerable valor económico e interés medioambiental, como selenio, cobalto y molibdeno. Es deseable entender el comportamiento de estos elementos cuando el proceso opera con recirculación de polvos. En este estudio, el efecto de la recirculación de polvo al proceso de fusión de cobre en la distribución entre la mata, escoria y gas fue evaluado como una función del grado de la mata, cantidad de polvo recirculado, enriquecimiento de oxígeno y temperatura. Los resultados experimentales mostraron que el selenio puede ser concentrado a altos rangos de mata y altas concentraciones de oxígeno en el gas de soplado. Sin embargo, los resultados sugieren que altas cantidades de recirculación no son factibles debido a que aumentan la pérdida de elementos menores.

Síntesis, caracterización fisicoquímica y del estado sólido de asparaginatos de cobre, magnesio, manganeso y zinc

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Julie Fernanda Benavides Arévalo

Full Text Available Introducción: la deficiencia de minerales en la población está asociada a enfermedades metabólicas, hormonales e inmunológicas. Usualmente, los minerales son suplementados en el organismo en forma de sales inorgánicas, las cuales pueden causar molestias gástricas y baja absorción en dependencia del tipo de sal empleado. Estudios previos muestran una adecuada absorción y ausencia de efectos gástricos cuando los minerales están asociados a ligandos orgánicos como enzimas, proteínas y particularmente aminoácidos. Objetivo: determinar mediante un estudio de preformulación la viabilidad de utilizar asparaginatos de cobre, magnesio, manganeso y zinc en suplementos nutricionales. Métodos: se realizó la síntesis y la verificación de formación de los complejos por espectroscopia infrarroja por transformada de Fourier y difracción de rayos X de polvos. Se evaluó la solubilidad, la constante de disociación, la eficiencia de la disolución y las propiedades físicas del estado sólido (morfología, distribución y tamaño de partícula, índice de Haussner, porosidad y compresibilidad de los complejos. Se determinó la compatibilidad de los complejos con excipientes. Resultados: en los espectros infrarrojos se observó la participación del grupo carboxilo de la asparagina en la formación del enlace de coordinación de los complejos. En los difractogramas de rayos X se mostró la ausencia de los materiales de partida y la cristalinidad en los complejos. La solubilidad, la constante de disociación y la eficiencia de la disolución de los complejos, establecieron su carácter anfótero. Conclusiones: los resultados en las propiedades físicas del estado sólido, la humedad y la compatibilidad con excipientes, establecen que las formulaciones de los aparaginatos de cobre, magnesio, manganeso y zinc tienen propiedades reológicas adecuadas para propósitos farmacéuticos.

EVALUACIÓN DE LA BIOACUMULACIÓN Y TOXICIDAD DE CADMIO Y MERCURIO EN PASTO LLANERO (Brachiaria dictyoneura)

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ARROYAVE Q, Catalina; ARAQUE M, Pedronel; PELAEZ J, Carlos A

2010-01-01

Se estudia la transferencia de mercurio y cadmio desde el sistema suelo hacia Brachiaria dictyoneura en función de la capacidad bioindicadora y bioacumuladora. Durante la evaluación de cadmio en B. dictyoneura se observó una disminución en el crecimiento del 65%. La toxicidad de cadmio se correlaciona con la acumulación consecutiva del catión durante el tiempo de monitoreo. En el tratamiento con mercurio, a partir de los 30 días de exposición, se observó disminución en el contenido del catión...

Avaliação do teor de cobre e zinco em carnes cruas, processadas termicamente, resfriadas e congeladas no período de um mês Evaluation of copper and zinc in meats thermally processed and conservated in freezer for a month

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Édira Castello Branco de Andrade

2004-09-01

Full Text Available Para que elementos químicos, como o cobre e o zinco, sejam utilizados pelos sistemas biológicos, é necessário que estejam disponíveis para absorção, sendo assim, apenas a sua abundância na natureza não é fator que garanta a sua absorção. As carnes bovinas e de aves são de grande importância na alimentação, justamente por serem alimentos fonte de proteínas de alto valor biológico e lipídios. Processos de conservação através de refrigeração e congelamento, bem como processamento térmico, podem alterar fisicamente as carnes. Este trabalho tem como objetivo avaliar o comportamento de cobre e zinco em carnes resfriadas e conservadas em temperatura de congelamento por um período de 1 mês, processadas termicamente e in natura. Os teores de cobre e zinco foram determinados através da espectroscopia de absorção atômica. Os dados foram tratados estatisticamente através do teste de Grubs e t de Student. Mesmo com perdas no processamento térmico, e com a conservação em temperatura de congelamento durante o período de 4 semanas, o teor de cobre na maioria das amostras estudadas foi superior a 0,025mg%, e o do zinco superior a 0,3mg% para as amostras de carnes de aves e 0,6mg% para as amostras de carnes bovinas.Copper and zinc can appear in nature under chemical forms, the solubility of theses metals can be determinated bio-availability.Meats from cattle or chicken are sources of proteins and lipids wich are very important for human nutrition. Thermal processing as cooking, refrigeration and freezing can modifie fisical and chemical structures of meats tissues.Samples of meat from cattle and chicken, in two batches of each variety, were thermally processed and conservated in freezer for a month, and the total ratio of copper and zinc was determined through flame atomic absorption spectroscopy. Both the Grubs and t test by Student were used for the analysis. It was observed that, after freezing and thermal processing copper

Dinámica del cadmio en suelos cultivados con papa en Nariño, Colombia.

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Liliana Insuasty B

2008-01-01

Full Text Available Se evaluó la fijación y movilidad de cadmio en suelos dedicados al cultivo de papa en Túquerres, Pasto y Guachucal. Se tomaron muestras de suelos no disturbadas en cilindros de PVC, las cuales, luego de aplicaciones fraccionadas de cadmio con dosis de 0, 50,100 y 150 ppm, se incubaron a capacidad de campo durante cuatro meses. En estos suelos los contenidos de cadmio total e intercambiable no sobrepasaron los límites permisibles establecidos por Organización Mundial de la Salud-Organización de las Naciones Unidas para la Agricultura y la Alimentación (OMS-FAO; no obstante, la mayor cantidad del elemento se localizó en la parte superior de los núcleos, lo cual indica baja movilidad del elemento en el perfil.

Aplicação de água residuária de suinocultura em solo cultivado com soja: cobre e zinco no material escoado e no solo Swine wastewater application in soil cultivated with soybean: copper and zinc in the runoff material and in the soil

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Tatiane C. dal Bosco

2008-12-01

Full Text Available O objetivo deste trabalho foi avaliar a poluição difusa referente ao cobre e ao zinco no solo e no material de escoamento superficial quando da aplicação de água residuária de suinocultura (ARS em solo cultivado com soja, sob condição de chuva simulada. O experimento foi instalado em Toledo - PR, sendo aplicadas ao solo cinco taxas de ARS (0; 50; 100; 150 e 200 m³ ha-1 no ciclo, em três repetições por tratamento, divididas em seis aplicações ao longo do ciclo da soja. Foram instaladas calhas coletoras do material escoado e fizeram-se seis simulações de chuva durante o experimento, resultando em seis coletas do material escoado. Ao final do ciclo da soja, foram coletadas amostras de solo em cada uma das parcelas experimentais, em três profundidades, para a determinação do pH, da capacidade de troca de cátions, da matéria orgânica, do cobre e do zinco. Observou-se que houve perda de cobre e de zinco via escoamento superficial e que as maiores concentrações de cobre foram verificadas nas profundidades de 20-40 e 40-60 cm, enquanto o zinco apresentou maior concentração na camada de 0-20 cm e, ao final do experimento, aumentou nas demais profundidades.The objective of this work was to evaluate the diffuse pollution regarding to the copper and to the zinc in the soil and in the runoff material due to the application of swine wastewater (ARS in soil cultivated with soybean, under simulated rain condition. The experiment was installed in Toledo - PR, Brazil, and it was applied to the soil five rates of ARS (0; 50; 100; 150 and 200 m³ ha-1 in the cycle, in three replications for treatment, divided in six applications along the cycle of the soybean. Gutters were installed gutters to collect the runoff material and it was made six rain simulations during the experiment, resulting in six collections of the runoff. At the end of the soybean cycle, soil samples were collected in each one of the experimental plots, at three depths

Movilidad del cadmio en suelos cultivados con trigo en Tangua, Nariño, Colombia

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Menjivar F. Juan

2006-06-01

Full Text Available

En muestras de suelo colocadas en núcleos de PVC (11 cm de diámetro y 40 cm de largo se aplicaron en forma fraccionada 0, 50, 100 y 150 ppm de cadmio y se incubaron por cuatro meses manteniendo la humedad a capacidad de campo. Se evaluó el contenido de Cd-total y Cd – intercambiable en la parte superior, media e inferior de los núcleos. Los contenidos de Cd- total en el testigo no sobrepasaron el límite permisible de 3 ppm esta­blecido por OMS-FAO. La mayor concentración Cd – total aplicado y Cd intercambiable se encontró en la parte superior de los núcleos, lo cual indica baja movilidad del cadmio en el perfil de los suelos evaluados.

Palabras claves: Cadmio Triticum aestivum, Nariño, suelos

Estado legal mundial del cadmio en cacao (Theobroma cacao): fantasía o realidad

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Jiménez Tobón, Claudia Stella

2015-01-01

El cacao colombiano está bien posicionado en el mercado internacional por su sabor y aroma; sin embargo, en materia de contaminantes, existe a una preocupación a escala nacional debido a la presencia de cadmio en las semillas. Este metal, cuando se acumula en el organismo, es el responsable de serias enfermedades que lo deterioran lentamente. Aunque se conoce que a partir del 2019, la Comunidad Europea comenzará a exigir al cacao y sus derivados unos niveles máximos de cadmio, no es bien cono...

Contaminación por metales pesados en la Cuenca del Río Moche, 1980 – 2010, La Libertad – Perú

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Félix Huaranga Moreno

2012-01-01

Full Text Available La contaminación de las aguas continentales es un problema de escala mundial,principalmente debido alimpacto de los relaves mineros. Utilizando tecnologías de punta,como plantas de neutralización de aguasácidas,muchas empresas están mitigando el impacto de su funcionamiento; por lo que tomando comoreferencia los cambios en la concentración de metales pesados presentes en aguas, suelos y cultivos de lacuenca alta, media y baja del río Moche, se realizaron muestreos de agua en ocho estaciones del río Moche(Trujillo, Perú, y en cuatro sectores de sus márgenes para suelos y cultivos. Los metales pesados másrepresentativos en el agua se presentaron en el Cuenca Alta durante el año de 1980: hierro (557.500 ppm,plomo (100.375 ppm, cadmio (4.550 ppm, cobre (6.900 ppm, zinc (262.900 ppm y arsénico (9.000 ppm;mientras que en los suelos las mayores concentraciones se encontraron en la margen derecha de la CuencaBaja para el año 1980: hierro (83.400 mg/kg; plomo (0.820 mg/kg; cadmio (0.012 mg/kg; cobre (1.240mg/kg; zinc (0.380 mg/kg y arsénico (0.016 mg/kg; en relación con la acumulación de metales en loscultivos, el hierro (0.6525 mg/kg fue el de mayor predominio, siendo la yuca (Manihot esculentus el cultivodonde se presentó. Se concluye que la mayor contaminación a nivel del análisis de agua se presentó en lacuenca alta y durante el año de 1980; mientras que la margen derecha de la cuenca media presentó los mayoresniveles de contaminación en las muestras de suelos; así como a nivel de los cultivos, la yuca (Manihotesculentus fue la especie más contaminada.

Biodisponibilidade de cobre de diferentes fontes para coelhos

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Cavalcante S.G.

2002-01-01

Full Text Available Utilizaram-se 140 coelhos das raças Nova Zelândia Branco e Califórnia, com 60 dias de idade, de ambos os sexos, distribuídos em 14 tratamentos experimentais, com o objetivo de determinar a biodisponibilidade de cobre (Cu de três fontes inorgânicas, óxido de cobre (tratamento OC, sulfato de cobre (tratamento SC e carbonato de cobre (tratamento CC e uma orgânica, quelato de cobre (tratamento QC, usadas nas concentrações de 0, 20, 40, 80 e 160 ppm para a curva padrão. O maior consumo de ração ocorreu nos tratamentos 80SC, 80OC, 40SC, 160SC, 0C, 20SC, 40CC e 40OC e os menores resultados nos tratamentos 160QC, 40QC, 80CC, 160CC e 160OC (R²= 0,1913. Para ganho de peso o melhor tratamento foi 80SC e o pior 80CC (R²=0,2358. Para conversão alimentar, os tratamentos 80CC, 80SC, 0C, 20SC e 80QC apresentaram nessa ordem os maiores valores e o menor valor foi em 40QC. Para o cobre no fígado, o tratamento 160CC apresentou o maior valor, e 80SC e 40SC os menores. Não houve diferenças com relação ao sexo, mas os animais Nova Zelândia Branco apresentaram maior deposição de cobre. Pelos resultados chegou-se à equação de regressão: Y Cu= 1,37 + 3,83 x1 + 2,77 x2 + 2,83 x3 + 2,84 x4 + 2,84 x5 (R² = 0,3288.

Actividad inhibitoria del crecimiento bacteriano por cobre nanoestructurado obtenido de minerales de la región Marañón: comparación con cobre comercial

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Jaime Sánchez-Venegas

2016-12-01

Full Text Available En el presente trabajo se reporta la actividad inhibitoria del crecimiento bacteriano por nanopartículas de cobre cementado y de cobre comercial. Se utilizaron las cepas de Staphylococcus aureus ATCC 6538 (Gram positiva y Escherichia coli ATCC 35218 (Gram negativa para determinar el efecto inhibitorio mediante la concentración mínima inhibitoria de las nanopartículas diluidas en caldo de cultivo nutritivo y distribuidas en placas de ELISA. Las muestras de cobre cementado (obtenidas por procesos hidrometalúrgicos y de cobre comercial fueron nanoestructuradas empleando un equipo de molienda mecánica. Los resultados indican que las nanopartículas de cobre comercial (a 2.5 horas de molienda muestran acción inhibitoria del crecimiento de la cepa S. aureus y no así en la cepa E. coli. Asimismo, se determinó que la concentración mínima inhibitoria de la muestra de cobre comercial fue de 20 μg/mL frente a S. aureus. El cobre cementado (en su forma sólida y nanoestructurada no mostró efecto inhibitorio del crecimiento en ninguna de las dos cepas estudiadas.

Contaminación de alimentos marinos por cadmio en Lima, 2015

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Gloria Marín Vallejos

2015-12-01

Full Text Available Los objetivos fueron determinar las concentraciones de cadmio en ocho especies de alimentos marinos y comparar con los valores máximos permitidos según la Comisión de la Unión Europea en su Reglamento (CE Nº 1881/2006 y su modificatoria Reglamento (UE N° 488/2014. La investigación fue de carácter descriptivo, trasversal. Las muestras fueron de 100 g de cada ejemplar de pescado en tres oportunidades; los ejemplares fueron: jurel (Trachurus picturatus murphyi, langostinos (Penaeus vannamei, conchas abanico (Argopecten purpuratus, conchas blancas (Semele sp, choros (Aulacomya ater, almejas (Gari solida, machas (Mesonesma donacium y pota (Dosidicus gigas recolectadas al azar en el terminal pesquero de Villa María del Triunfo, provenientes del litoral de la región Lima, sub área 3: Chorrillos – Islas Pachacámac. El proceso de análisis se realizó por espectrofotometría de absorción atómica. Como resultados de los promedios de las concentraciones de cadmio tenemos: en pescados, jurel (Trachurus picturatus murphyi fue 0,35 mg/kg peso fresco; en crustáceos, langostino (Penaeus vannamei fue 0,42 mg/kg peso fresco; en moluscos bivalvos tenemos conchas blancas (Semele sp, conchas abanico (Argopecten purpuratus, choros (Aulacomya ater, machas (Mesonesma donacium y almejas (Gari solida fueron 0,82 – 0,83 – 1,00 – 1,28 y 1,39 mg/kg peso fresco respectivamente. Con este estudio se concluyó que las concentraciones de cadmio en pescados, en moluscos bivalvos y cefalópodos superan los límites permitidos, pero en crustáceos no superan estos límites.

Extração seqüencial de cobre, ferro e zinco em ervas medicinais Sequential extraction of copper, iron and zinc in medicinal plants

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Édira Castello Branco de Andrade

2005-12-01

Full Text Available A técnica de especiação dos metais, que determina a concentração das formas físico-químicas individuais dos elementos que, em conjunto, constituem a concentração total dos mesmos na amostra, possibilita a obtenção de novos dados para prever sua absorção. O termo biodisponibilidade, proposto inicialmente para a área farmacológica, indica a proporção do nutriente que é absorvida e utilizada pelo organismo. Sendo assim, a determinação do teor total do metal ingerido pelo organismo não possibilita traçar um perfil da eficiência de sua absorção. Técnicas de especiação química, como a extração seqüencial, podem auxiliar na avaliação da biodisponibilidade dos minerais. Amostras de ervas medicinais de dois lotes foram analisadas quanto aos teores totais de cobre, ferro e zinco por espectroscopia de absorção atômica na chama, e a extração seqüencial foi aplicada. Os testes F, de Dixon e t-student foram utilizados. Observou-se que, em média, as amostras apresentaram teores totais de cobre, ferro e zinco de respectivamente 1,37 mg%, 5,13 mg% e 2,96 mg%. Ao comparar estes valores com os teores destes metais em alimentos de origem vegetal, verifica-se que as ervas medicinais analisadas podem ser consideradas boas fontes de metais. Observou-se ainda que os metais cobre, ferro e zinco se encontram nas amostras sob no mínimo quatro espécies químicas distintas e que os extratores I e Iv foram os de melhor eficiência. Técnicas de especiação química que possam identificar os compostos obtidos nos diferentes extratores podem auxiliar na avaliação da biodisponibilidade dos mesmos e, conseqüentemente, nos processos de absorção.Speciation of the metals, which determines the concentration of the elements individual physiochemical forms that, together, constitute the total concentration of them in the sample, makes possible the attainment of new data to foresee its absorption. The term bioavailability, considered

Fracciones biodisponibles de arsénico, plomo, cadmio y mercurio en sedimentos de corrientes superficiales seleccionadas

OpenAIRE

Hernández Peñalver, María Teresa; García Melián, Maricel; Cañas Pérez, Regla; Sardiñas Peña, Olivia

1999-01-01

Se realizó la determinación de las fracciones biodisponibles de arsénico, cadmio, plomo y mercurio en los sedimentos de 10 ríos seleccionados, los cuales abastecen a comunidades de más de 5 000 habitantes en Cuba. Se efectuó la extracción en la fracción compuesta por partículas menores de 63 mym, con ácido clorhídrico 0,5 mol/L. En los casos de arsénico y cadmio, todas las muestras presentaron niveles inferiores a los límites de cuantificación de los métodos de ensayo. Las medianas de las con...

Cobre antimicrobiano contra patógenos intrahospitalarios en Perú

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Edwin Neciosup

2015-01-01

Full Text Available Introducción: Las infecciones intrahospitalarias (IIH constituyen un problema de salud pública que generan grandes gastos por parte de los gobiernos, debido a que los patógenos causantes de IIH presentan resistencia a fármacos y generan una mayor permanencia de los pacientes, pues la infraestructura hospitalaria constituye un reservorio favorable para los patógenos. Las superficies de cobre surgen como opción sanitaria y efectiva para controlar el crecimiento y propagación de estos patógenos. Objetivos: Evaluar la actividad bactericida de las superficies de cobre contra los principales bacterias patógenas causantes de IIH (Escherichia coli, Pseudomonas aeruginosa y Staphylococcus aureus. Diseño: Estudio experimental con muestreo no probabilístico. Lugar: Hospital Regional Docente las Mercedes (HRDLM y Hospital Provincial Docente Belén (HPDB, Lambayeque, Perú. Materiales: Nueve cepas bacterianas, 3 de E. coli , 3 de P. aeruginosa y 3 de S. aureus; superficies metálicas (1 cm² de cobre y acero inoxidable (control . Intervenciones: Las 9 cepas bacterianas fueron proporcionadas por los hospitales HRDLM (4 cepas y HPDB (5 cepas. Los análisis de ANOVA y de Tukey fueron aplicados para evaluar la actividad bactericida de las superficies de cobre y acero inoxidable contra las 9 cepas causantes de IIH, usando los programas estadísticos Minitab y Sigmaplot, respectivamente. Principales medidas de resultados: Diferencias en el crecimiento bacteriano sobre superficies de cobre o acero inoxidable, con respecto al tiempo de exposición. Resultados: Las 9 cepas -3 de P. aeruginosa, 3 de E. coli y 3 de S. aureus - expuestas a superficies de cobre fueron eliminadas en 10, 15 y 60 minutos, respectivamente. La carga bacteriana de las células expuestas en superficies de acero inoxidable permaneció constante y viable por periodos mayores a 60 minutos. Además, las superficies de cobre eliminaron más rápido a las bacterias Gram negativas (P

El cobre y la estrategia fiscal óptima para Chile

OpenAIRE

Alejandro Drexler; Eduardo Engel; Rodrigo Valdés

2001-01-01

Este trabajo analiza la estrategia fiscal óptima para Chile, determinando el gasto total y fiscal de la economía, así como de la carga tributaria considerando (i) el problema de distribución intergeneracional de los recursos asociados al cobre; (ii) que los ingresos del cobre son volátiles, transitorios y afectan al resto de la economía; y (iii) que el ingreso total y tributario aumenta en el tiempo. Se considera tres modelos, teoría del ingreso del cobre permanente, teoría del ingreso fiscal...

The Cadmio XML healthcare record.

Science.gov (United States)

Barbera, Francesco; Ferri, Fernando; Ricci, Fabrizio L; Sottile, Pier Angelo

2002-01-01

The management of clinical data is a complex task. Patient related information reported in patient folders is a set of heterogeneous and structured data accessed by different users having different goals (in local or geographical networks). XML language provides a mechanism for describing, manipulating, and visualising structured data in web-based applications. XML ensures that the structured data is managed in a uniform and transparent manner independently from the applications and their providers guaranteeing some interoperability. Extracting data from the healthcare record and structuring them according to XML makes the data available through browsers. The MIC/MIE model (Medical Information Category/Medical Information Elements), which allows the definition and management of healthcare records and used in CADMIO, a HISA based project, is described in this paper, using XML for allowing the data to be visualised through web browsers.

Influência da competição catiônica nos valores de fator de retardamento e coeficiente de dispersão-difusão de zinco e cobre no solo Effect of the cationic competition on the retarding factor and dispersion-diffusion coefficient of zinc and copper in soil

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Mauro A. Martinez

2001-05-01

Full Text Available Objetivando-se avaliar os efeitos da competição catiônica nos valores do fator de retardamento (f r e do coeficiente de dispersão-difusão (D realizaram-se ensaios de mobilidade de metais em colunas de lixiviação submetidas a escoamento permanente e saturado. Foram aplicadas soluções de zinco (700 mg L-1, cobre (200 mg L-1 e de zinco mais cobre, nas mesmas concentrações, para obtenção das respectivas curvas de eluição. Os materiais de solo utilizados foram retirados dos horizontes A, B e C de um Latossolo Vermelho-Amarelo, álico (LVa e de um Podzólico Vermelho-Amarelo, câmbico fase terraço (PVc coletados no município de Viçosa, MG. Nos solos estudados em todos os horizontes, o cobre apresentou maiores valores de fator de retardamento que o zinco, indicando apresentar maior interação com a fração sólida do solo. As baixas velocidades de avanço das soluções proporcionaram a obtenção de baixos valores de coeficiente de dispersão-difusão no solo e a competição catiônica diminuiu a capacidade de retenção dos cátions no solo.The effects of the cationic competition on the retarding factor (fr and the dispersion-diffusion coefficient (D were evaluated with conducting metal mobility trials in leaching columns submitted to a saturated and steady flow. Solutions of zinc (700 mg L-1, copper (200 mg L-1 and zinc plus copper in the same concentrations, were used to obtain elution curves. Soil materials from the A, B and C horizons of Oxisol (LVa and of Ultisol (PVc, collected in Viçosa, MG, were used. In all soil materials used, copper presented higher retarding factor values than zinc, which indicates a higher copper-soil interaction. The low velocities of the solutions resulted in low dispersion-diffusion coefficient values. Cationic competition decreased the soil retention capacity for the cations.

Lixiviación amoniacal de polvos de fundición de cobre y precipitación como sulfuro de cobre

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Morales, A.

2009-12-01

Full Text Available The effect of ammonia on the leaching of copper smelter dust and copper precipitation from these solutions as sulphide using sulfur and sulfur dioxide was studied. The precipitation was done in ammoniacal media because this solution produced more satisfactory results at room temperature that a sulphuric media. A solid was precipitated containing 60 % of copper of the dust smelter. The other waste generated contained around 80 % of the arsenic of the original copper smelter dust. Based on the preliminary results obtained in this work it will propose a procedure for the recovery of copper as sulphide from copper smelter dust with parallel confinement of arsenic.

Se estudió el efecto del amoniaco en la lixiviación de polvos de fundición de cobre y en la precipitación de sulfuro de cobre, usando azufre y dióxido de azufre desde estas disoluciones. La precipitación se realizó en un medio amoniacal para tener rendimientos satisfactorios a temperatura ambiente. Se precipitó un sólido que recupera alrededor del 60 % del cobre contenido en los polvos de fundición. El otro residuo generado contenía del orden del 80 % del arsénico de los polvos originales. Sobre la base de estos resultados preliminares, se planteó un procedimiento para la recuperación de cobre desde los polvos de fundición y para el confinamiento del arsénico.

ELIMINAÇÃO DO COBRE CONTAMINANTE DAS AGUARDENTES DE CANA

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JOãO BOSCO FARIA

2007-02-01

Full Text Available Considerando que a contaminação por cobre é uma constante na maioria das aguardentes de cana produzidas no Brasil, problema que impossibilita sua exportação, os autores decidiram estudar condições de operação que, reduzindo o teor de cobre contaminante, ou mesmo eliminando-o, garantissem qualidades organolépticas ideais ao produto, o que não é verificado quando a aguardente é destilada na ausência de cobre. O uso de dois alambiques de partes intercambiáveis, um de cobre e um de aço inoxidável, permitiu verificar que a contaminação só se dá nas partes descendentes do aparelho, enquanto o uso do metal nas partes ascendentes assegura o desenvolvimento de boas qualidades organolépticas. Assim, os autores projetaram uma peça de cobre carregada de fios do mesmo metal para ser colocada no capitel do alambique. Esse artifício aumentaria a superfície de cobre a que ficam expostos os vapores do “vinho de cana” na parte ascendente do aparelho, durante a destilação, evitando que eventual “azinhavre” fosse arrastado na condensação dos vapores já na serpentina, que não deve conter cobre em sua estrutura, sendo preferencialmente de aço inoxidável. Os resultados obtidos justificaram o recurso.

Metalurgía y comercio del cobre en la Europa prehistórica

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Edward SANGMEISTER

2009-10-01

Full Text Available Al ocuparnos de la propagación de la técnica del cobre quizá sea oportuno empezar por plantearnos la cuestión de cómo se le pudo ocurrir de repente a un hombre de la Edad de Piedra el coger el cobre como primer metal para elaborarlo. Aunque carecemos de todo testimonio seguro es probable que el hombre, en su búsqueda de piedras utilizables —entre las cuales también había materiales que le interesaban por sus hermosos colores—, haya tropezado con el cobre, que aparece en muchos sitios y se puede recoger en superficie. Precisamente su semejanza con dichas piedras semipreciosas verdes es muy grande, a causa de la pátina verde que se crea en el cobre nativo.

Influence of roadside pollution on the phylloplane microbial community of Alnus nepalensis (Betulaceae

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S.R Joshi

2008-09-01

Aureobasidium pollulans, Fusarium oxysporum and Mortierella sp. in the polluted site may be due to their resistance to pollutants in roadside conditions. Rev. Biol. Trop. 56 (3: 1521-1529. Epub 2008 September 30.La región nororiental de la India está experimentando un rápido desarrollo industrial y debido a la topografía montañosa de la región, los automóviles descargan variedad de contaminantes. Actividades humanas como moler piedra y construir caminos también aumentan el polvo atmosférico y la contaminación con metales pesados. Este estudio compara microorganismos en superficies foliares del árbol Alnus nepalensis (Betulaceae. Se estudió uno sitio en una intersección de Shillong, con alta densidad de tráfico (8 000-9 000 vehículos pesados/día, tomada como el sitio contaminado, y otro en un bosque aproximadamente a 500 m de la carretera (sitio no contaminado. Se contabilizaron bacterias, hongos, plomo, zinc, cobre, cadmio y sulfuro. La población bacteriana era más alta en el sitio no contaminado. La población bacteriana mostró una correlación negativa significativa con el contenido de plomo, cinc, cobre, cadmio y sulfuro foliares en el sitio contaminado, mientras que en el sitio no contaminado la correlación fue insignificante. La población de hongos también fue más alta en el sitio no contaminado. Un total de 29 especies de hongos fueron aislados A. nepalensis: 16 en el sitio contaminado y 28 en el no contaminado. Algunas especies de hongos como Mortierella sp., Fusarium oxysporum y Aureobasidium pollulans fueron dominantes en el sitio contaminado. El número de hongos y bacterias fue significativamente menor en el sitio contaminado. El coeficiente de correlación indicó un efecto perjudicial de metales como el plomo, el zinc, el cobre, el cadmio y el sulfuro en esta comunidad que habitan superficies de hojas. La especificidad de ciertos hongos al sitio no contaminado se puede atribuir a su sensibilidad a la contaminación. El predominio de

Un método para el tratamiento de las pilas y baterías domésticas usadas de tamaño medio. III Parte. Propuesta de un método para su tratamiento

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de Juan, D.

1996-06-01

Full Text Available A method for the primary treatment of spent batteries and domestic cells is proposed. Basic processes for the secondary treatment, metals recovering and detoxifying wastes are developed. Iron is directly recovered in the primary treatment as a ferrous scrap. Zinc is recovered from ammoniacal solution obtained in primary treatment by means of a hydrothermal process. For recovering cadmium, copper and nickel, a cementation with zinc dusts is proposed along with the application of the COCADEX process. Detoxifying the fraction bioxide obtained and the mercury recovered are made by heat treatment at 300- 400°C. The heat treatment wastes and the non ferrous fraction can be treated in a Waelz furnace, for the simultaneous recovery of zinc and cadmium contained in the waste as a Waelz oxide.

Se propone un método para llevar a cabo el tratamiento primario de las pilas y baterías domésticas usadas. Se desarrollan los procesos necesarios para realizar el tratamiento secundario, recuperar los metales contenidos y separar los componentes tóxicos de los residuos. En el tratamiento primario se recupera el hierro directamente como una chatarra férrea. El cinc se recupera de la disolución amoniacal procedente del tratamiento primario mediante un proceso hidrotermal. Para la recuperación del cadmio, cobre y níquel se propone su cementación con polvo de cinc y posterior aplicación del proceso COCADEX. La eliminación de los productos tóxicos de la fracción bióxido resultante, así como la recuperación del mercurio se realizan mediante calcinación a 300-400 °C. El residuo de calcinación y la fracción no férrea se pueden tratar conjuntamente en un horno Waelz para recuperar simultáneamente el cinc y el cadmio residual como óxido Waelz.

Determinación de la adsorción de cadmio mediante isotermas de adsorción en suelos agrícolas venezolanos

OpenAIRE

Subero Neudis; Sánchez Nereida; Rivero Carmen

2011-01-01

El cadmio es un metal pesado que tiende a acumularse en la superficie del suelo. En los últimos años, las actividades antropogénicas han ocasionado un incremento en los niveles de este metal en suelos agrícolas generando gran preocupación ambiental debido a su movilidad y lixiviación en el perfil del suelo y a la facilidad con que es absorbido por las plantas. El objetivo de este trabajo fue determinar la capacidad de adsorción de cadmio, de cuatro suelos venezolanos de uso agrícola con difer...

Cuantificación de plomo, cadmio y cromo mediante sialoquímica

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GONZÁLEZ MIREYA

1997-01-01

Full Text Available Objetivo. Determinar las concentraciones de plomo, cadmio y cromo, y establecer su posible asociación con diferentes factores sociodemográficos. Material y métodos. Se seleccionó una muestra representativa de 100 estudiantes de posgrado de la Facultad de Odontología de la Universidad Nacional Autónoma de México (UNAM, a los cuales se les colectó saliva total no estimulada. Dichas muestras fueron analizadas por espectrofotometría de absorción atómica con horno de grafito. Resultados. Metales pesados como el plomo, el cadmio y el cromo se encuentran en concentraciones mucho más altas que las informadas en la literatura: Pb, = 3.10 m g/dL-1, máxima: 16.8 my g/dL-1, y mínima: 0.04 my g/dL-1; Cd, = 0.25 my g/dL-1, máxima: 2.04 my g/dL-1, y mínima: 0.004 my g/dL-1; y Cr, = 1.43 my g/dL-1, máxima: 4.82 my g/dL-1, y mínima: 0.05 my g/dL-1. Asimismo, variables como la zona de residencia, el sexo, la edad y la ingesta de comida enlatada no influyen en los niveles de plomo y cromo. Sin embargo, en el caso del cadmio y la edad existe una asociación inversa (ji²= 5.9012, p<= 0.05; gamma = -0.5224, p<= 0.05. Conclusiones. La sialoquímica juega un papel importante en la detección de contaminantes, fármacos, drogas y enfermedades locales y sistémicas. La contaminación por metales pesados sigue siendo un problema de salud pública, por lo que el gobierno debe consolidar un programa cuyo objetivo sea eliminar los diferentes contaminantes del ambiente. Asimismo, se deben realizar otros estudios para verificar la asociación de variables como sexo, edad, uso de cerámica vidriada, alimentación y zona de residencia con las concentraciones de metales pesados en saliva.

SeCD electronic folder: CADMIO's application for the medical folder of a service for the care of drug addicts.

Science.gov (United States)

Della Valle, R M; Baldoni, A; De Rossi, M; Ferri, F

1998-01-01

In this paper we will describe the SeCD (Service for the Care of Drug addicts) electronic folder, a specific application of CADMIO [1] (Computer Aided Design for Medical Information Objects) system. CADMIO is a system for the definition, construction and management of multimedia clinical folders. The Ser.T. (Servizio per la Tossicodipendenza/Service for Drug Addicts) has earned a very special place within the Italian clinical structures as well as any service for drug addicts has done in the rest of the world. Such a structure has special needs and the characteristics of its medical folders are very different from any other folder. Actually, a Ser.T. has to keep updated the patient situation either from the clinical point of view as well as the psychiatric one. Moreover, it must keep track of the clinician subjective considerations about the patient psychic state and his situation in regard of the law. So, we had to redesign some of the features of the existing CADMIO application, to accommodate such highly not structured data into objects easily manipulated by an informative system. The objectives we hope to achieve were mainly two: To show that a well designed adaptive system can be easily exploited to support even very complex and poorly structured data types and actions To design data structures able to accommodate medical, psychiatric and administrative data in an homogeneous manner.

Flotación en columnas de complejos cobre - amilxantato en función del pH

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Francisco J. Tavera-Miranda

2009-03-01

Full Text Available La diferencia de solubilidad de los complejos amilxantato de cobre(I y de cobre(II es un elemento determinante en la implementación de procesos de flotación para recuperar cobre disuelto, aspecto en el que no se ha profundizado. En este trabajo se estudia el comportamiento de ambos complejos en función del pH del medio, evaluando los resultados a partir de su contribución específica en la recuperación y la cinética del proceso de flotación, el cual se lleva a cabo en una columna de laboratorio utilizando amilxantato de potasio como colector. El rango de pH utilizado (4 a 13 permite evaluar el efecto de las transformaciones que tienen lugar en el sistema amilxantato- cobre-agua. Los resultados indican el incremento de la recuperación de cobre con el incremento del pH del medio hasta valores de pH 11 y muestran una fuerte dependencia de la recuperación con las características químicas del sistema, el cobre flotado se incrementa marcadamente al incrementarse la concentración de la especie cristalina amilxantato de cobre(I, asociado a esto se manifiesta un incremento de la fracción de gas retenido y el flujo de superficie de las burbujas, las cuales tienen una incidencia directa sobre la cinética del proceso de flotación.

Evolución temporal de la contaminación por plomo y cadmio en la zona intermareal de la ría de Vigo

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M. Pérez López

2004-12-01

Full Text Available En el presente trabajo se han recogido muestras de lapa (Patella vulgata L. y alga verde (Ulva lactuca en un mismo punto de muestreo de la ría de Vigo, con una periodicidad mensual, a lo largo de un año, analizándose por medio de voltamperometría de redisolución anódica la concentración en dos metales pesados con claras repercusiones toxicológicas, cadmio y plomo, en estas muestras, así como en el agua marina. Los resultados obtenidos mostraron la mayor concentración de ambos metales en los tejidos blandos de las lapas frente a las valvas de estos moluscos, con valores máximos en el caso del plomo próximos a 3 ppm (valva de lapa, mientras que para el cadmio se situó en torno a 1,1 ppm (alga verde. El estudio estadístico permitió poner en evidencia una clara correlación estadística entre los valores de cadmio y plomo cuantificados en las muestras de algas.

Disponibilidad de cobre, hierro, manganeso, zinc en suelos del NO argentino Pant availability of copper, iron, manganesum and zinc in the north west of Agentina

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Núria Roca

2007-07-01

Full Text Available Cobre, hierro, manganeso y zinc son cuatro metales esenciales para el crecimiento vegetal. A pesar de las pequeñas cantidades requeridas por las plantas, los suelos agrícolas suelen ser deficitarios en uno o más micronutrientes de forma que su concentración en los tejidos de los vegetales cae por debajo de los niveles que permiten un crecimiento óptimo. La naturaleza del suelo juega un papel fundamental en la disponibilidad de micronutrientes y en su comportamiento a nivel suelo-planta. Los objetivos planteados en el presente estudio son: a establecer la relación entre los parámetros edáficos y la dinámica de los metales dentro del perfil del suelo, y b determinar la biodisponibilidad y zonas de deficiencia de micronutrientes en suelos agrícolas y suelos con riesgo de salinización. El porcentaje de materia orgánica es el factor determinante en el contenido y distribución de los micronutrientes en el suelo objeto de estudio, siendo el horizonte superficial el de mayor acumulación. Tanto CuDTPA, FeDTPA como MnDTPA tienen cierta movilidad en el perfil, mientras que ZnDTPA permanece adsorbido sin un desplazamiento vertical. El ZnDTPA es el único metal que además, muestra diferencias como consecuencia de la salinidad y granulometría de los suelos. No obstante, las condiciones geoquímicas del suelo implican una baja extractabilidad y una cierta dificultad de absorción de los micronutrientes por parte de las plantas.Copper, iron, manganese and zinc are among the essential elements for plant growth. Despite the small amounts required by plants, agricultural soils are usually deficient in one or more of these micronutrients. Therefore, their concentration in plant tissues falls below the optimum levels. Soil nature plays a fundamental role in the availability of micronutrients and their behavior at a soil-plant level. The aims of this paper were: a to establish the relationship between soil properties and micronutrient dynamics within

Amenizante Orgânico e Eucalyptus grandis para Fitoestabilização de Solo Contaminado com Cobre

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Rudinei De Marco

2017-04-01

Full Text Available RESUMO Este trabalho avaliou a utilização de turfa como amenizante e Eucalyptus grandis como técnica de fitoestabilização para remediar solo contaminado com cobre. O trabalho foi conduzido sob delineamento inteiramente casualizado em arranjo fatorial (2 × 6, sendo sem e com adição de turfa (200 mL L-1 de solo e seis doses de cobre adicionadas ao solo (0 mg kg-1, 60 mg kg-1, 120 mg kg-1, 180 mg kg-1, 240 mg kg-1, 300 mg kg-1 de solo, com seis repetições. Avaliaram-se a altura das mudas, o diâmetro do colo, a massa seca radicular e aérea, a área superficial específica, os teores e a quantidade acumulada de cobre no sistema radicular e na parte aérea e o índice de translocação. A adição de turfa possibilitou efeito amenizante da contaminação por cobre e favoreceu o crescimento das mudas. As mudas de Eucalyptus grandis apresentam elevado acúmulo de cobre nas raízes, o que permite indicá-la como promissora para fins de fitoestabilização de solos contaminados com cobre.

Aplicación del proceso BRISA al tratamiento de menas de cobre conteniendo atacamita

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Carranza, F.

2003-12-01

Full Text Available The current treatment of copper ores containing atacamite and secondary copper sulphides consists of heap leaching, by the TL process. Copper recoveries by this treatment are very low (less than 50 % for operating times higher than six months. In order to improve the copper extraction yields, several treatment options are presented in this work, wich consist on promoting the acid leaching of the atacamite and the indirect bioleaching (BRISA process of the secondary copper sulphides. All the options lead to improved copper recoveries in comparison with the current treatment. An economic estimation of each option of treatment is included, with really attractive results.

El tratamiento actual de minerales que contienen atacamita y sulfures secundarios de cobre tiene lugar según el proceso TL. La recuperación de cobre en estos procesos es escasa (inferior al 50 %, para tiempos de operación superiores a seis meses. Para mejorar el rendimiento de extracción de cobre, se plantean, en este trabajo, diferentes alternativas de tratamiento que incluyen la potenciación de la lixiviación acida de la atacamita y la biolixiviación por contacto indirecto (proceso BRISA de los sulfuros secundarios de cobre. Todas las alternativas ofrecen aumentos sustanciales de la recuperación de cobre. Se incluye la evaluación económica preliminar de cada una de ellas, con resultados francamente atractivos.

Análisis de Cadmio y Plomo en aguas superficiales por potenciometría de Stripping

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Juan Miguel Arias

2010-12-01

Full Text Available Se realizó la implementación y validación de una metodología analítica para determinar la presencia de cadmio y plomo en aguas supjerficiales como herramienta para la descripción del estado actual y el control cualitativo y cuantitativo de las descargas de estos metales peligrosos en los cuerpos de agua.

Experimentos de química recreativa con sulfato de cobre pentahidratado

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Santiago Heredia-Avalos

2006-01-01

Full Text Available En este trabajo se proponen varias experiencias sencillas usando sales de sulfato de cobre pentahidratado. Todas ellas pueden realizarse en casa con utensilios de cocina y usando sustancias baratas, la mayoría de las cuales pueden encontrarse en un supermercado. Las experiencias propuestas permiten estudiar el proceso de cristalización del sulfato de cobre pentahidratado, reacciones de oxidación-reducción, de formación de precipitados e, incluso, reacciones de formación de complejos. Estas experiencias pretenden despertar el interés de los alumnos por la química.

Efecto de la recirculación de polvo de fundición de cobre de Chile con altos contenidos de impurezas en la distribución de impurezas durante el proceso de fusión

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Montenegro, V.

2010-02-01

Full Text Available Usually, dust generated during the copper smelting process by the Teniente Converter and the Flash Smelting Furnaces in Chile, contains high concentrations of copper, zinc, arsenic, antimony and other metals. In general, the dust is recirculated to the smelting process or it is directed to hydrometallurgical process for recovery and stabilization. However, in recent years the generation of dust has increased because of the degradation of the quality of the concentrate. In addition, the environmental regulations have become stricter. It is therefore desirable to understand the behavior of those elements, when the smelting process operates with recirculation of dust. In this study, the effect of dust recirculation to smelting process on the distribution among the matte, slag and gas phases was evaluated, as a function of matte grade, amount of recirculated dust, oxygen enrichment and temperature. It was found that the concentration in thematte of the impurities such as arsenic, antimony and bismuth, increased slightly with recirculation of dust. On the other hand, the concentration of lead and zinc depend of the direct recirculation of dust to the process. Additionally, it was found that high concentrations of arsenic and antimony in the dust may lead to the formation and precipitation of copper arsenates and other metals (speiss, which may generates important operational problems.

Usualmente, el polvo generado durante el proceso de fusión de concentrado de cobre por el Convertidor Teniente y el Horno Flash en Chile, contienen altos contenidos de cobre, zinc, arsénico y antimonio, entre otros metales. En general, el polvo se recircula al proceso de fusión o se envía a procesos hidrometalúrgicos para recuperación y estabilización. Sin embargo, en los años recientes, la generación de polvo ha aumentado debido a la baja en la calidad del concentrado. Adicionalmente, las normas ambientales se han vuelto más estrictas. Por lo tanto, es

Utilización del cobre en dietas hipograsas

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Aguirre, M.

1996-12-01

Full Text Available The objective of this study was to investigate both the dietary copper utilization and the body copper content in rats fed either low fat diets (2% or normal fat diets (8% containing olive oil, sunflower oil and palm oil (olein fraction, by two different balance techniques. Seven groups of Wistar rats were used. One group was killed on the first experimental day being utilized as control of initial body copper content. Six groups of rats were fed, over 15 days, semipurified diets varying only in the fat level, three of them containing 8% of fat, and the other three 2%. The overall copper balance was studied by calculating differences between the initial and final body copper content. During the last week, another copper balance was carried out by monitoring intake and faecal copper excretion. Body mass, and liver, spleen, skin, erythrocytes and serum copper contents were also examined. The copper utilization was lower in 2% fat rats, this was caused by food intake decrease but also by the lower copper bioavailability in 2% fat diets. The corporal, liver and spleen copper contents were reduced, and liver, skin and serum copper concentrations also decreased in the rats fed on 2% fat diets. Palm olein (8% versus olive and sunflower oil produced a lower efficiency of copper absorption.

Se propuso estudiar la influencia del consumo de dietas pobres en grasa a base de aceite de oliva, girasol o aceite de palma (fracción oleína sobre la utilización del cobre dietético por dos técnicas diferentes de balance, así como sobre sus contenidos corporales. Se utilizaron siete grupos de ratas Wistar, uno de ellos sacrificado el día primero del experimento, sirvió como control del contenido cúprico corporal inicial; seis grupos de ratas fueron alimentadas durante 15 días con dietas semisintéticas, tres de ellos con las grasas al 8% y los otros tres al 2%. En ellos se estudió el balance global del cobre mediante diferencia entre los

Cobre no controle da verminose gastrintestinal em ovinos Copper on the control of gastrintestinal nematodes in sheep

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Isabel Gonçalves de Gonçalves

2004-02-01

Full Text Available Este estudo teve o objetivo de verificar o tempo de proteção do cobre contra reinfecções por helmintos gastrintestinais de ovinos em pastejo. Foram utilizados 32 ovinos da raça Corriedale, com aproximadamente 18 meses de idade, mantidos em campo nativo naturalmente contaminado por trichostrongilídeos. Os animais foram pesados e dosificados. Após, foram alocados a quatro grupos experimentais: T I (tratado com cobre e necropsiado no 28ºdia; T II (sem cobre e necropsiado no 28º dia; T III (tratado com cobre e necropsiado no 56ºdia; T IV (sem cobre e necropsiado no 56º dia. Os grupos T I e T III receberam, via oral, uma cápsula gelatinosa de quatro gramas, contendo 3,4 gramas de óxido de cobre. Os ovinos foram avaliados semanalmente através de contagem de ovos por grama de fezes (OPG, volume globular (VG, aspartato aminotransferase (AST e concentrações de cobre no plasma. Ao abate, foram determinados: carga parasitária, concentrações de cobre no fígado e peso dos fígados. Os resultados demostraram que os níveis de cobre no plasma não tiveram alterações significativas (P>0,05 entre os diversos tratamentos. Quanto aos níveis de cobre detectados no fígado dos animais abatidos observou-se que os lotes medicados com cobre, apresentaram níveis mais elevados que os não medicados (Pe TII. Quanto à avaliação do OPG, não foram observadas diferenças significativas entre os grupos (P>0,05. Com relação aos parasitos gastrintestinais, detectou-se que a administração de cobre contribuiu significativamente para uma menor reinfecção apenas pelo Haemonchus contortus e somente nos animais abatidos na quarta semana após o tratamento, quando a redução foi de 60% nos medicados (P0,05. Com base nesses resultados, podemos concluir que 3,4 gramas de óxido de cobre podem ser efetivas na redução das reinfecções por H. contortus, durante quatro semanas sem causar toxicidade para ovinos criados extensivamente.The aim of this work

Tóxidad de cadmio y plomo en pasto tanner Brachiaria arrecta

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Manuel Peláez

2014-12-01

Full Text Available Se evaluó fisiopatías en Brachiaria arrecta expuestas a contenidos tóxicos de cadmio y plomo en el invernadero de la Universidad Nacional de Colombia Sede Palmira, se doparon plántulas sanas de 20 días de edad bajo cultivo hidropónico. El objetivo fue describir síntomas crecientes por intoxicación con el diseño de una escala valorativa de daños crecientes, adicionalmente se evaluaron cambios histológicos de raíz tallo y hojas mediante microscopia de luz de alta resolución (MLAR. Las plantas fueron sometidas a estrés abiótico con los tratamientos de sales de CdCl2 en concentración de 10 ppm, y de Pb (NO32 500 ppm, respectivamente. Los resultados principales mostraron un mayor detrimento cuando las plantas fueron expuestas al metal plomo que al cadmio en las raíces, tallos y hojas. Se apreciaron deformaciones extremas en paredes celulares de las células del cortex y en la endodermis de la raíz; en las hojas los daños fueron notorios para ambos metales sobre todo en el parénquima clorofílico y en la deformación de paredes de la epidermis tanto en haz como envés; en los tallos aparecieron deformaciones de las células del parénquima de relleno cuando ocurre bioacumulación intensa de plomo. Estos resultados sugieren que la bioconcentración en los tejidos vegetales ocasiona trastornos histológicos, que pueden involucrar una red trófica y por consiguiente consecuencias en la Salud Pública.

EFEITO DO COBRE SOBRE O CRESCIMENTO E QUALIDADE DE MUDAS DE Stryphnodendron polyphyllum Mart. E Cassia multijuga Rich.

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Rodrigo Ferreira da Silva

2014-09-01

Full Text Available http://dx.doi.org/10.5902/1980509815730A contaminação do solo com cobre tem se tornado comum em regiões de mineração e agrícolas pelo uso de fungicidas a base de cobre e aplicação de dejeto líquido de suíno ao solo, causando redução na produtividade das plantas. O trabalho objetivou determinar o efeito de doses de cobre no crescimento e qualidade de mudas de Barbatimão (Stryphnodendron polyphyllum Mart. e Cássia (Cassia multijuga Rich.. O delineamento experimental foi inteiramente casualizado num fatorial (2 x 4, sendo as duas espécies florestais, e quatro doses de cobre: 0; 150; 300 e 450 mg kg-1, com 10 repetições. Avaliou-se a altura de planta, diâmetro do colo, peso da matéria seca radicular e da parte aérea, comprimento e área superficial específica radicular, e os índices de qualidade de mudas: relação entre altura da parte aérea e diâmetro do coleto; altura da parte aérea e peso da matéria seca da parte aérea e o Índice de Qualidade de Dickson. Os resultados demonstram que as doses de cobre testadas não influenciam a qualidade de mudas da Cássia enquanto o Barbatimão mantém a qualidade de mudas até 300 mg kg-1 de cobre adicionado ao solo. O Barbatimão apresenta maior crescimento e qualidade de mudas que a Cássia em solo contaminado com cobre.

Caracterización química de pigmentos cerámicos a base de sulfoseleniuro de cadmio

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Gazulla Barreda, M. F.

2013-12-01

Full Text Available The present paper addresses the development of a methodology that allows the complete chemical characterisation of zirconcadmium sulfoselenide ceramic pigments including minor and major elements. To develop the methodology, five zircon-cadmium sulfoselenide pigments with different hues were selected, studying the different measurement process steps, from sample preparation to the optimisation of the measurement of the different components of the pigments by spectroscopic techniques (WD-XRF and elemental analysis by combustion and IR detection. The chemical characterisation method developed was validated with synthetic standards prepared from the mixture of certified reference materials and pure oxides because no certified referenced materials of this type of pigments were commercially available. The developed method can be used for a complete chemical characterization of zircon-cadmium sulfoselenide ceramic pigments with a very low uncertainty for all the elements analysed.El objetivo del presente trabajo es el desarrollo de una metodología que permita la caracterización química completa de pigmentos cerámicos a base de sulfoseleniuro de cadmio, incluyendo elementos mayoritarios y minoritarios. Para desarrollar la metodología, se seleccionaron cinco pigmentos a base de sulfoseleniuro de cadmio, estudiando las distintas fases del proceso de medida, desde la preparación de la muestra hasta la optimización de la medida de los distintos componentes de los pigmentos por técnicas espectroscópicas (WD-FRX y análisis elemental por combustión y detección mediante IR. El método de caracterización química desarrollado se validó con patrones sintéticos preparados a partir de la mezcla de materiales de referencia certificados y óxidos puros debido a que no existen comercialmente materiales de referencia certificados de este tipo de pigmentos. Este método se puede utilizar para la caracterización química completa de pigmentos a base de

Diagrama de estabilidad termodinámico del sistema de flotación cobre/agua/amilxantato

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Beatriz Ramírez-Serrano

2015-05-01

Full Text Available El propósito del trabajo fue obtener el diagrama de estabilidad termodinámico que caracteriza al sistema de flotación cobre/agua/amilxantato, como parte del fundamento teórico necesario para el análisis del proceso de flotación de iones cobre con el reactivo colector de flotación amilxantato de potasio. A partir del sistema de reacciones químicas fundamentales y con ayuda del sofware Medusa se obtuvo el diagrama Eh-pH en el cual se definen las zonas de estabilidad de las diferentes especies químicas y se establece que en el rango de pH de 4 a 13 coexisten las especies xantogenadas de cobre(I y (II cuya relación disminuye con el incremento del pH.

REMOCIÓN DE COBRE Y NÍQUEL POR INTERCAMBIO CATIÓNICO CON UNA ZEOLITA NATURAL

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Arnoldy Estupiñan

2010-10-01

Full Text Available Se empleó la zeolita natural clinoptilolita, para remover cobre y níquel de aguas residuales de una industria de galvanotecnia. La capacidad de intercambio determinada para la zeolita transformada al estado homoiónico sódico, fue de 0,794 meq/g para cobre y 0,447 meq/g para níquel. Se realizaron ensayos en cochada y en columna, alcanzando éste último un mayor acercamiento al equilibrio. En los ensayos de regeneración, la zeolita sódica concentró el cobre hasta 23,5 veces con respecto al valor que presenta en los enjuagues de los baños de recubrimiento en medio ácido, mostrando su potencialidad para usarla en el tratamiento de estos residuos, por su efectividad y bajo costo.

Efecto de la calidad de la materia orgánica asociada con el uso y manejo de suelos en la retención de cadmio, en sistemas altoandinos de Colombia

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Isabel del Socorro Bravo Realpe

2014-04-01

Full Text Available El cadmio (Cd proveniente de suelos afectados por intemperismo y actividades antropogénicas puede producir efectos tóxicos, asociados con la baja afinidad de las formas adsorbentes, la alta solubilidad y la movilidad. Es de gran importancia conocer los fenómenos de adsorción y los factores de movilidad de este elemento y predecir su posible toxicidad en suelos de la región altoandina de Colombia cuyo sistema de uso está cambiando a pasturas y cultivos con aplicación de fertilizantes fosfatados que contienen cadmio. Para determinar la influencia en la retención y el factor de movilidad de Cd en estos suelos de la subcuenca Rio Las Piedras, Departamento del Cauca (Colombia, utilizados en sistemas de bosque, cultivo de papa (Solanum tuberosum y pastura de kikuyo (Pennisetum clandestinum fueron caracterizados por sus propiedades físicas y químicas, encontrando alta acidez, presencia de alófanos, alto contenido de carbono orgánico, alta capacidad de intercambio catiónico, y baja densidad. Para determinar la influencia en la retención y el factor de movilidad de cadmio, la calidad de la materia orgánica (M.O fue evaluada mediante índices de humificación obtenidos por la caracterización de sus diferentes fracciones. La retención fue evaluada mediante isotermas de adsorción de Freundlich en ácidos húmicos en suelos de los tres sistemas de uso. Los valores encontrados de K (máxima capacidad de adsorción y n (fuerza de retención fueron, respectivamente, de 131.98 y 1.18 en suelos de bosque, 340.93 y 1.19 en cultivo, y 170.36 y 1.19 en pasturas. La calidad de la M.O. tiene un efecto significativo en estos procesos, así, una mejor calidad redunda en menor movilidad de cadmio, previniendo contaminación de aguas subterráneas y toxicidad por bioacumulación de cadmio.

Enfermedades profesionales en la industria del cobre: extracción, manufactura y reciclaje

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C.D. Cabrera-Marutz

2014-12-01

Full Text Available Introducción: El cobre por sus características se utiliza en una gran variedad de aplicaciones en la industria energética, sus múltiples usos unidos a la expansión y evolución de los diversos sectores industriales lo hacen una pieza fundamental para lograr el desarrollo sostenible de la sociedad actual. La minería, procesamiento, reciclaje y su transformación genera riqueza, crea puestos de trabajo y a su vez puede suponer un riesgo potencial para el desarrollo de enfermedades profesionales. Objetivo: Realizar una revisión bibliográfica que permita identificar las principales enfermedades profesionales que desarrollan los trabajadores de la industria de cobre. Metodología: Se realizó búsqueda bibliográfica en las siguientes bases de datos: MEDLINE (PUBMED, OSH UPDATE, IBECS, LILACS. Se revisó la literatura científica en busca de posibles enfermedades profesionales en la industria del cobre. Resultados: Se incluyeron en el estudio un total de 16 artículos científicos que cumplían los criterios de inclusión, agrupándolos en 4 categorías: cáncer de pulmón y vías respiratorias 10; 6 describían enfermedades respiratorias crónicas (neumoconiosis, EPOC; 5 se referían a otros tipos de cánceres (urotelial, Linfoma No Hodking, de estómago, de vejiga, de colon, de hueso, de hígado y 2 reportaron alergias de contacto. Conclusiones: Las principales enfermedades detectadas en los trabajadores de la industria del cobre fueron cáncer de pulmón y vías respiratorias y en segundo lugar enfermedades respiratorias crónicas. La minería fue el sector más afectado. Existe escasa literatura científica que identifique la aparición de enfermedades profesionales relacionadas con el reciclaje de cobre.

CUANTIFICACIÓN, CARACTERIZACIÓN Y COMPOSICIÓN DEL MATERIAL PARTICULADO 2,5, PROCEDENTE DEL USO DE LA COMBARBALITA

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Ricardo Zamarreño

2015-01-01

Full Text Available En este trabajo, se muestran los resultados del material particulado P.M. 2,5 en la ciudad de Combarbalá, por la explotación y tallado de la “Combarbalita”. Los monitoreos se realizaron entre los meses de septiembre del 2010 y mayo del 2011. Determinando P.M. 2,5 con una bomba succionadora, cuantificando la concentración de algunos metales, utilizando espectroscopia de absorción atómica. Comprobando las características morfológicas de los componentes, usando la técnica de microscopia de inmersión. El promedio del PM 2,5 es de 22,50 μg/m3, estando bajo los valores recomendados por la EPA. Los elementos con mayores concentraciones son el Hierro, el Cobre, el plomo y el Zinc, el Cadmio posee la menor concentración. Las partículas de 2.5 μm y menores bordean el 36.11% del total analizado, las que tienen dimensiones de 4 a 10 μm suman el 50%. Concluyendo que Combarbalá posee bajos niveles de contaminación de material particulado P.M. 2,5.

CARACTERIZACION DE UN MINERAL DE COBRE EN ARGENTINA PARA LA PRODUCCION DE MATTE.

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VANESA BAZÁN

2011-01-01

Full Text Available Argentina, posee minerales cuyas reservas la potencian para constituirse en un fuerte abastecedor regional. Actualmente, se han realizado proyectos de exploraciones y explotación de minerales de cobre que poseen una ley entre 0,5% y 0,8% generalmente libre de impurezas como Sb, As, Pb, Bi y Hg. [1, 2, 3, 4] Este hecho indicaría que puede existir un gran potencial para el desarrollo de la pirometalurgia del cobre, dado que hasta el momento no existen avances en este sentido. En este trabajo se presentan resultados de un estudio realizado sobre un mineral de baja ley de Cu, en el cual se identifi can sus fases mediante microscopía óptica, ensayos de fl otación contemplando diferentes condiciones, con el objetivo de obtener concentrados de distintas calidades. Finalmente, para comprender aspectos del proceso de obtención del cobre se realiza una simulación del proceso de fusión en el horno fl ash basado en balances de masa y energía.

Sensibilidade a cobre, estreptomicina e oxitetraciclina em Xanthomonas spp. associadas à mancha-bacteriana do tomate para processamento industrial

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Quezado-Duval Alice Maria

2003-01-01

Full Text Available Apesar de amplamente empregados em lavouras de tomate para processamento industrial no Brasil, fungicidas cúpricos e antibióticos registrados para uso agrícola nem sempre resultam em controle eficiente das bacterioses que afetam a cultura. O aparecimento de estirpes resistentes é uma das causas dessa baixa eficiência. Avaliou-se, in vitro, a sensibilidade a cobre, estreptomicina e oxitetraciclina de 389 isolados de Xanthomonas spp. associadas à mancha-bacteriana do tomateiro, sendo 92 de X. axonopodis pv. vesicatoria (60 do grupo "A"/raça T1 e 32 do "C"/raça T3, 93 de X. vesicatoria (grupo "B"/raça T2 e 204 de X. gardneri (grupo "D"/raça T2. Os isolados foram obtidos de plantas doentes em campos comerciais de tomate para processamento industrial nos estados de Goiás, Minas Gerais, Pernambuco e Bahia, nos anos de 1995 a 1998 e em 2000. Alíquotas de 5 ml de suspensões bacterianas foram depositadas em meio Nutriente-Ágar suplementado com sulfato de cobre, nas concentrações de 50 e 200 µg/ml; sulfato de estreptomicina, a 25 e 200 µg/ml e cloridrato de oxitetraciclina, a 25 µg/ml. Nenhum isolado foi resistente a oxitetraciclina, como também nenhum foi resistente ao cobre na concentração de 200 µg/ml do sulfato de cobre. No entanto, houve diferença entre isolados quanto à sensibilidade ao sulfato de cobre na concentração de 50 µg/ml e ao sulfato de estreptomicina nas duas concentrações empregadas. As freqüências de isolados de X. gardneri, X. axonopodis pv. vesicatoria (grupos "A" e "C" e X. vesicatoria resistentes à estreptomicina (25 µg/ml do produto usado foram, respectivamente, 98%, 38% e 2%, ao passo que, ao cobre, foram, respectivamente, 48%, 4% e 74%. Todos os isolados do grupo "C" foram sensíveis à estreptomicina e 97% sensíveis ao cobre.

Tratamiento metalúrgico de los óxidos Waelz mediante lixiviación alcalina utilizando carbonato amónico

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Meseguer, V.

1997-04-01

Full Text Available A method to carry out the treatment of the Waelz oxides is proposed, and the principal stages implicated are studied laboratory-scale. The process consists of the oxides leaching with an ammonium carbonate/ammonia solution, followed the recovery of the zinc leached by means of its precipitation as zinc basic carbonate. The process stages that have been studied are: Waelz oxides leaching, loaded leach purification, zinc precipitation, zinc basic carbonate washing and zinc basic carbonate transformation. The designed treatment presents a null environmental impact, and more than 90 % of the zinc contained in the Waelz oxides, as well as 80 % of the copper and cadmium contents could be recovered. Also, the process presents great flexibility as soon as zinc could be recovered in the most convenient form (zinc metal, oxide or salt.

Se propone un método para el tratamiento de los óxidos Waelz, y se estudian, a nivel de laboratorio, las principales etapas implicadas en el mismo. El proceso consiste básicamente en la lixiviación de los óxidos con una disolución de carbonato amónico/amoniaco, y posterior recuperación del cinc lixiviado mediante su precipitación como carbonato básico de cinc. Las etapas que constituyen el proceso y que han sido objeto de estudio son: lixiviación de los óxidos Waelz, purificación de la lejía concentrada de lixiviación, precipitación del cinc, lavado del carbonato básico de cinc precipitado y transformación del carbonato básico de cinc. El tratamiento diseñado presenta un impacto ambiental prácticamente nulo, y con el mismo se puede recuperar más del 90 % del cinc contenido en los óxidos Waelz, así como el 80 % del cobre y del cadmio. Además, el proceso presenta gran versatilidad en cuanto que el cinc se puede recuperar en el estado más conveniente (cinc metal, óxido o sal.

COBRE Research Workshop on Higher Education: Equity and Efficiency.

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Chicago Univ., IL.

This document comprises 8 papers presented at the COBRE Research Workshop on Higher Education. The papers are: (1) "Schooling and Equality from Generation to Generation;" (2) "Time Series Changes in Personal Income Inequality: The United States Experience, 1939 to 1985;" (3) "Education, Income, and Ability;" (4) "Proposals for Financing Higher…

Conflicto y Modernización en la Gran Minería del Cobre (1950-1970

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Ángela Vergara Marshall

2004-12-01

Full Text Available Este artículo analiza el proceso de modernización en la Gran Minería del Cobre en Chile entre 1950 y 1971. En primer lugar, se examinan las causas, nacionales e internacionales, que llevaron a las empresas del cobre a introducir cambios en la forma de producción, organización de la fuerza de trabajo y labores administrativas. En segundo lugar, se analiza el impacto que tuvo la modernización en las condiciones de vida y de trabajo de los mineros del cobre. En términos generales, este artículo plantea que aunque la modernización minera aumentó la productividad de esta industria, al mismo tiempo esta agudizó el conflicto laboral en la minería y deterioró la posición de las empresas del cobre en Chile.This article focuses on the process of modernization in the Large Scale Copper Industry between 1950 and 1971. First, it looks at the national and international factors that led copper companies to introduce substantial changes in the organization of production, the labor force, and administration. Second, it analyzes the impact of modernization on working, economic, and living conditions in the copper mines. In a time of increasing nationalism and political radicalization, these schemes not only led to intense confrontation with labor unions but also undermined the position of the US copper companies in Chile.

Determinação Simultânea de Metais em Cachaças Utilizando Voltametria de Redissolução Com Eletrodos de Nanotubo de Carbono e Calibração Multivariada.

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FERREIRA, R. J.

2015-01-01

Cachaças são destilados provenientes de cana de açúcar, gerando teores alcoólicos em faixas de porcentagem de 38% a 48% em volume. Devido a seu grande consumo no país e sua complexidade em constituição química, promoveu-se neste trabalho a determinação dos metais cobre, zinco, cadmio e chumbo, que em quantidades elevadas, são nocivos à saúde e ao metabolismo humano. Determinou-se as concentrações desses metais por meio da espectrometria de emissão óptica com plasma indutivamente acoplado (ICP...

Ventajas Del Perenox. Fungicida de la Casa COOPER sobre el Caldo Bordelés y otros productos a base de cobre.

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Universidad Nacional de Colombia Facultad de Ciencias Agrarias

1941-10-01

Full Text Available "Perenox" es un Oxido de Cobre especialmente preparado, presentado en la forma de un polvo dispersivo extraordinariamente soluble en agua. Contiene 50 % de Cobre, mientras que los cristales del Sulfato de Cobre sólo contienen 25%, Una libra de "Perenox" reemplaza a lo menos 4 libras de Sulfato de Cobre y la correspondiente cantidad de cal y adherentes necesarios para la preparación del Caldo Bordelés. El "Perenox" se puede usar en todos esos casos en que entra el empleo del Caldo Bordelés, como por ejemplo para fumigar contra la "Gota" de la papa, la "Sigatoka" del banano, enfermedades de los cafetos, árboles de cacao, árboles frutales, etc. Se puede agregar al "Perenox" arseniato de plomo u otras substancias cuando se desee también controlar plagas de insectos.

Influência do zinco na incidência de doenças do cafeeiro Zinc influence on coffee diseases

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Vicente Luiz de Carvalho

2008-06-01

Full Text Available Em cafeeiros, poucos estudos foram feitos relacionando aumento ou diminuição da resistência das plantas às doenças, com alteração dos níveis de nutrientes utilizados. Com este trabalho, objetivou-se estudar os efeitos do sulfato de zinco aplicado isoladamente, e associado com fungicidas e cloreto de potássio sobre a ferrugem, cercosporiose e manchas foliares do cafeeiro. O trabalho foi desenvolvido em uma lavoura de café em produção, onde foram testados oxicloreto de cobre, tebuconazole, sulfato de zinco + cloreto de potássio e sulfato de zinco e nas subparcelas foram realizadas diferentes concentrações de sulfato de zinco: ausência, 0,3 %, 0,6 % e 1,2 %. Verificou-se que os tratamentos com oxicloreto de cobre e tebuconazole reduziram a incidência e severidade de ferrugem, a incidência de cercosporiose, de manchas foliares (phoma e ascochyta e a desfolha, independente das concentrações de sulfato de zinco utilizadas. Concentrações de sulfato de zinco na faixa de 0,6 % - 0,75 % apresentaram menor severidade da ferrugem e o aumento nas concentrações de sulfato de zinco aumentou a incidência de cercosporiose, manchas foliares e a desfolha dos cafeeiros.The are few studies have been done related to the increase or decrease of disease resistance in coffee plants, with alteration from plant nutrient levels. The ain of this work was to verify the effect of zinc sulfate, applied either alone or in association with fungicides, and the effect of potassium chloride on coffee leaf rust, brown-eyes and leaf stains in coffee plants. Copper oxichloride, tebuconazole, sulfate of zinc + potassium chloride and sulfate of zinc were applied on plots and concentrations of zinc sulfate (0,0 %, 0,3 %, 0,6 % and 1,2 % were applied on sub plot. Treatments with copper and tebuconazole reduced the incidence and severity of rust, the incidence of brown-eyes and stains leaf (phoma and ascochyta and the defoliate independent of the zinc sulfate

Efectos gammágenos del cobre en los aceros inoxidables 18Cr8Ni

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Botella, J.

1997-10-01

Full Text Available From a series of 22 typical 18Cr8Ni stainless steel 40 kg ingots, with copper variable concentrations from 0.6 to 3.0 weight %, δ-ferrite is measured with a ferrite-meter device, calculating a nickel equivalent of 0.27 for copper. Some differences between the 8-ferrite and that on calculated by DeLong -excluding the copper γ-gene action- have been found because of different solidification and cooling regimes in ingot and weld cases.

A partir de una serie de 22 lingotes de 40 kg de aceros inoxidables típicos 18Cr8Ni, con concentraciones variables de cobre entre 0,6 y 3,0 % en masa, se mide la ferrita δ mediante un medidor de ferrita y se deduce para el cobre un equivalente en níquel de 0,27, a la vez que se establecen ciertas diferencias entre los contenidos de ferrita δ medida y la deducida según DeLong -excluida la acción gammágena del cobre- por el hecho de solidificar en lingotes en vez de la típica solidificación de soldaduras.

Bioaccumulation of copper, zinc, cadmium and lead by Bacillus sp., Bacillus cereus, Bacillus sphaericus and Bacillus subtilis Bioacumulação de cobre, zinco, cádmio e chumbo por Bacillus sp., Bacillus cereus, Bacillus sphaericus e Bacillus subtilis

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Antonio Carlos Augusto da Costa

2001-03-01

Full Text Available This work presents some results on the use of microbes from the genus Bacillus for uptake of cadmium, zinc, copper and lead ions. Maximum copper bioaccumulations were 5.6 mol/g biomass for B. sphaericus, 5.9 mol/g biomass for B. cereus and B. subtilis, and 6.4 mol/g biomass for Bacillus sp. Maximum zinc bioaccumulations were 4.3 mol/g biomass for B. sphaericus, 4.6 mol/g biomass for B. cereus, 4.8 mol/g biomass for Bacillus sp. and 5.0 mol/g biomass for B. subtilis. Maximum cadmium bioaccumulations were 8.0 mol/g biomass for B. cereus, 9.5 mol/g biomass for B. subtilis, 10.8 mol/g biomass for Bacillus sp. and 11.8 mol/g biomass for B. sphaericus. Maximum lead biomaccumulations were 0.7 mol/g biomass for B. sphaericus, 1.1 mol/g biomass for B. cereus, 1.4 mol/g biomass for Bacillus sp. and 1.8 mol/g biomass for B. subtilis. The different Bacillus strains tested presented distinct uptake capacities, and the best results were obtained for B. subtilis and B. cereus.Este trabalho apresenta resultados de acumulação dos íons metálicos cádmio, zinco, cobre e chumbo por bactérias do gênero Bacillus. A bioacumulação máxima de cobre foi 5,6 mol/g biomassa para B. sphaericus, 5,9 mol/g biomassa para B. cereus e B. subtilis, e 6,4 mol/g biomassa para Bacillus sp.. A bioacumulação máxima de zinco foi 4,3 mol/g biomassa para B. sphaericus, 4,6 mol/g biomassa para B. cereus, 4,8 mol/g biomassa para Bacillus sp. e 5,0 mol/g biomassa para B. subtilis. A bioacumulação máxima de cádmio foi 8,0 mol/g biomassa para B. cereus, 9,5 mol/g biomassa para B. subtilis, 10,8 mol/g biomassa para Bacillus sp. e 11,8 mol/g biomassa para B. sphaericus. A bioacumulação máxima de chumbo foi 0,7 mol/g biomassa para B. sphaericus, 1,1 mol/g biomassa para B. cereus, 1,4 mol/g biomassa para Bacillus sp. e 1,8 mol/g biomassa para B. subtilis. As distintas linhagens de Bacillus testadas apresentaram variáveis capacidades de carregamento de íons metálicos, sendo os

Estudio de la conductividad de un material compuesto por cobre y óxido de grafeno reducido

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Rodríguez Escudero, Miguel Ángel

2016-01-01

Desde el descubrimiento de la corriente eléctrica, la principal aplicación del cobre es como conductor en todas aquellas aplicaciones relacionadas con ella, principalmente como componente eléctrico. En la actualidad, con el desarrollo de materiales metálicos, numerosos estudios científicos e industriales han llevado a crear diferentes tipos de aleaciones de cobre, con aplicaciones cada vez más amplias o altamente especializadas. En este desarrollo de materiales y tecnologías que mejoren la co...

AVANCES EN LA TECNOLOGIA DE EW DE COBRE: BARRAS INTERCALADAS SEGMENTADAS.

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VIDAL RUDLOFF, GUILLERMO A.; VIDAL RUDLOFF, GUILLERMO A.

2005-01-01

Esta tesis presenta la tecnología de barras intercelda segmentadas para los procesos electrometalúrgicos de cobre, aplicable en electroobtención y en electrorefinación. En estos procesos, la densidad de corriente real de cada electrodo difiere de la densi 126p.

Variabilidade espacial e disponibilidade de cobre e zinco em solos de vinhedos e adjacências

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Valladares,Gustavo Souza; Azevedo,Emílio Carlos de; Camargo,Otávio Antônio de; Grego,Célia Regina; Rastoldo,Alessandra Maria Cia Silva

2009-01-01

Com o tempo, o uso agrícola pode levar à contaminação do solo por metais pesados, principalmente por se servir de insumos e agroquímicos que possuem cobre e zinco em sua composição. O objetivo deste trabalho foi determinar os teores de cobre e zinco disponíveis no solo extraídos com DTPA e avaliar sua distribuição espacial empregando a geoestatística em áreas de vinhedos comerciais e experimentais e sob outros usos e coberturas nas adjacências das plantações. Foram coletadas amostras de terra...

Contenido de plomo y cadmio en aceites de girasol

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López Martínez, M. C.

2001-08-01

Full Text Available We have studied the lead and cadmium content in 21 samples of sunflower oil from Andalucía (Southern Spain. These elements are toxicological importance and the sunflower oil is widely consumed in Spain. Samples were mineralized with nitric acid and vanadium pentoxide as catalyst, and ana lyzed using electrothermal atomization atomic absorption spectroscopy. The temperature-time programme for the graphite furnace was optimized for each element, and the accuracy, precision, sensitivity and detection limit of the method were evaluated. Concentrations of lead ranged from not detectable to 167.58 μg/kg and cadmium concentrations ranged from 0.87 to 8.30 μg/kg. The data obtained are not excessive and similar to those mentioned by other authors; however, one sample of the total analyzed surpassed the limit of 0.1 ppm of lead proposed by the Spanish and European Legislation. A statistical significative correlation has been established between Pb and Cd levels (p Se ha determinado el contenido de plomo y cadmio en 21 muestras de aceite de girasol, todas ellas producidas en Andalucía (Sur de España. Ambos elementos tienen una gran importancia toxicológica y el aceite de girasol es muy consumido en España. Las muestras han sido mineralizadas con ácido nítrico, utilizando pentóxido de vanadio como catalizador, y analizadas mediante espectroscopia de absorción atómica con atomización electrotérmica. Se ha optimizado el programa temperatura-tiempo del horno de grafito para cada elemento y se ha evaluado la exactitud, precisión, sensibilidad y límite de detección del método. Las concentraciones de plomo han oscilado entre no detectables y 167.58 μg/kg y las concentraciones de cadmio entre 0.87 y 8.30 μg/kg. Estos datos no resultan excesivos y concuerdan con los aportados por otros autores; no obstante, una de las muestras analizadas supera el límite máximo de 0.1 ppm de Pb establecido en las Legislaciones Española y Europea. Se

Cobre labrado, alambique y aguardiente. Chile y Argentina, 1586-1850

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Pablo Lacoste

2016-01-01

Full Text Available El estudio examina el desarrollo de la producción, transporte y distribu- ción de cobres labrados y alambiques para elaborar aguardiente en Chile y el oeste de la actual Argentina, desde el primer alambique registrado (1586 hasta mediados del siglo XIX. Se detecta que el principal polo de manufactura de estos artefactos se encontraba en el Norte Chico de Chile, entre Huasco y La Serena. Desde allí, el uso de los alambiques se difundió por un amplio espacio. La ruta del alambique y el cobre labrado se extendió por 5.000 kilómetros, llegando a Guayaquil, Trujillo, Callao, Cinti, Jujuy y Salta por el norte; y a Valdivia y Chiloé por el sur, a ambos lados de la cordillera de los Andes. Floreció así un intenso proceso de integración socioeconómica regional, a la vez que se fortaleció el desa- rrollo agroindustrial con la posibilidad de destilar aguardientes. De esta manera se sentaron las bases para el surgimiento de varios productos típicos.

Promoción del crecimiento en plantas de Capsicum annuum por nanopartículas de óxido de zinc

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B. Méndez-Argüello; I. Vera-Reyes; E. Mendoza-Mendoza; L.A. García-Cerda; B.A. Puente-Urbina; R.H. Lira-Saldívar

2016-01-01

Las aplicaciones de la nanotecnología (NT) en los sistemas agrícolas son diversas, ofreciendo el potencial para mejorar significativamente su productividad y eficiencia al reducir costos y cantidades de agroquímicos aplicados. Las nanopartículas (NPs) metálicas de óxido de zinc, cobre y fierro, ya sean puras o mezcladas con plata, están siendo estudiadas globalmente por su potencial agrícola como promotores de crecimiento, nanofertilizantes y antimicrobiales. Considerando lo antes señalado, e...

Utilização dos modelos de Langmuir e de Freundlich na adsorção de cobre e zinco em solos Brasileiros Langmuir and Freundlich models applied to copper and zinc adsorption in Brazilian soils

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Lucília Alves Linhares

2010-07-01

Full Text Available Objetivou-se com este trabalho estudar o processo de adsorção de cobre e zinco em seis solos naturais do Estado de Minas Gerais e avaliar a influência que propriedades dos solos, como pH, capacidade de troca de cátions, teores de argila e de óxidos de ferro exercem no referido processo. Para construção das curvas de adsorção de cobre e zinco foram tomados 1 g de solo, em triplicata, suspensos em 25 mL de solução contendo os metais individualmente na forma de nitrato, preparadas em CaCl2 0,01 mol L-1 nas concentrações de 0 a 100 µg mL-1 e de 0 a 40 µg mL-1, respectivamente. A quantidade adsorvida dos elementos foi determinada indiretamente pelas quantidades dos mesmos, determinadas no sobrenadante, após a adsorção e os dados ajustados à isoterma de Langmuir e de Freundlich. Os solos com maiores teores de argila, óxidos de ferro e de pH mais elevado (Latossolo Vermelho distrófico, Chernossolo Argilúvico Carbonático saprolítico e Cambissolo Háplico Tb eutrófico latossólico, foram os que apresentaram os maiores valores de energia de ligação e capacidade máxima de adsorção, obtidos das isotermas de Langmuir. Estes resultados indicam uma baixa disponibilidade desses metais quando presentes no solo como contaminantes. Isso pode ser entendido como condição favorável, à priori, de menor contaminação do lençol freático. Para o Plintossolo Pétrico concrecionário distrófico, Cambissolo Háplico Tb distrófico típico e Neossolo Quartzarênico órtico latossólico os metais tendem ficar menos retidos e ou mais fracamente retidos aos constituintes do solo, tornando-se mais disponíveis à lixiviação.The objective of this work was to evaluate the adsorption of copper and zinc and the influence of soil properties, pH, cation exchange capacity, clay and iron oxide contents, in six natural soils of Minas Gerais State, Brazil. The copper and zinc adsorption curves were plotted for triplicate soil samples (1 g suspended

Efecto de la fertilización fosforada sobre el contenido de cadmio en cuatro suelos de Chile

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Bonomelli Claudia; Bonilla Carlos; Valenzuela Adriana

2003-01-01

Los fertilizantes fosforados pueden contener cadmio (Cd) y al utilizarlos pueden entrar en las cadenas tróficas. El objetivo de este estudio fue evaluar el efecto de la fertilización fosforada sobre la concentración de Cd disponible en cuatro tipos de suelos de Chile, que pertenecían a los ordenes Inceptisol, Alfisol, Ultisol y Andisol. Los dos tratamientos usados fueron el testigo sin fertilización y la aplicación de una dosis de corrección con un fertilizante comercial, superfosfato triple ...

Efecto de dos metales pesados, cadmio y níquel, sobre la eficiencia de remoción de carga orgánica de un reactor UASB a escala de laboratorio

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Luis Eduardo Forero

2004-01-01

Full Text Available Se realizaron ensayos en tres reactores UASB de tres litros cada uno, a un tiempo de retención hidráulico (TRH de cuatro horas y carga orgánica volumétrica de 4,8 g/L/d. Después de la fase inicial de arranque, tiempo de 4.000 horas para los tres reactores, se procedió a afectarlos de la siguiente forma: el primer reactor fue alimentado con 5 mg/L de cloruro de cadmio en forma continua, el segundo reactor fue alimentado con 10 mg/L de cloruro de níquel en forma continua también, mientras que el tercer reactor no se afectó con sustancia alguna y sirvió como control. La eficiencia de remoción de demanda química de oxígeno (DQO del primer reactor cambió del 60% de la fase de arranque (fase 1 al 18% en la fase afectada con cadmio (fase dos; la eficiencia de remoción de DQO en el reactor dos pasó del 60 al 24% y a su vez para el reactor tres control no hubo cambio significativo en dicha eficiencia. A su vez el reactor uno acumuló el cadmio en el lodo, mientras que el reactor dos no hizo lo propio con el níquel.

Nivel de inmunoglobulinas, incidencia de mastitis y fertilidad de vacas lecheras hipocuprémicas suplementadas con cobre

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Figueredo Rodríguez, Yoelsis; Gonzáles Cabrera, Noelia; Martínez Lemane, Julio; Mollineda Pérez, Ángel; García Gómez, Idaymi; García, Juan Ramón; Roller Gutiérrez, Felicia; Pedroso Sosa, Rodolfo

2017-01-01

La mastitis es una enfermedad global que afecta la productividad de la vaca lechera. La prevalencia de esta enfermedad está determinada en gran medida por la inmunodepresión que ocurre durante el  periodo  de transición.  La  suplementación  con  cobre  estimula  el  sistema  inmunológico.  Esta investigación  tuvo  como objetivo  determinar  el  efecto  de  la  suplementación  de  cobre &...

Variabilidad estacional de cadmio en un sistema de surgencia costera del norte de Chile (Bahía Mejillones del Sur, 23° S Seasonal variability of cadmium in a coastal upwelling system off northern Chile (Mejillones bay, 23° S

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JORGE VALDÉS

2006-12-01

Full Text Available Entre junio de 2002 y abril de 2003 se midió el contenido de cadmio total y disuelto entre la superficie y los 100 m de profundidad, en dos estaciones localizadas en la bahía Mejillones del Sur. El rango de cadmio total y cadmio disuelto en las aguas de esta bahía fue 0,41-10,7 y 0,08-1,61 nM, respectivamente, durante el período de muestreo. Los resultados fueron correlacionados con la estructura físico-química de la columna de agua al momento del muestreo, de manera de estudiar los patrones de variabilidad estacional de este metal en este sistema de surgencia. Las condiciones oceanográficas imperantes durante este período correspondieron a un año normal (no-El Niño. Las masas de agua presentes en la bahía correspondieron a agua subantártica, subtropical y ecuatorial subsuperficial, con diferentes grados de mezcla y estratificación durante el período de estudio. Los perfiles de cadmio presentaron una distribución vertical clásica de un micronutriente. Sin embargo estos perfiles presentaron leves diferencias que pueden ser atribuidas a la condición de mezcla de las masas de agua al interior de la bahía. Un análisis multivariado de los parámetros registrados indicó que la variación temporal de cadmio en las aguas superficiales está asociada a las fluctuaciones de la clorofila a y la temperatura. Esto sugiere que, a escala estacional, la producción de biomasa fitoplanctónica sería el principal factor que controla la distribución de cadmio en esta bahía. Por otro lado, a pesar de que el cadmio es un metal redox sensitivo no se encontró un efecto significativo de la disponibilidad de oxígeno sobre el comportamiento de este metal, de manera que la condición micróxica de las aguas de fondo de la bahía no sería un factor preponderante en el flujo de cadmio hacia los sedimentos. La razón Cd/PO4 encontrada en Mejillones es similar a la reportada en otras zonas costeras de Chile. Los bajos valores y la tendencia temporal

Efecto de la fertilización fosforada sobre el contenido de cadmio en cuatro suelos de Chile

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Bonomelli Claudia

2003-01-01

Full Text Available Los fertilizantes fosforados pueden contener cadmio (Cd y al utilizarlos pueden entrar en las cadenas tróficas. El objetivo de este estudio fue evaluar el efecto de la fertilización fosforada sobre la concentración de Cd disponible en cuatro tipos de suelos de Chile, que pertenecían a los ordenes Inceptisol, Alfisol, Ultisol y Andisol. Los dos tratamientos usados fueron el testigo sin fertilización y la aplicación de una dosis de corrección con un fertilizante comercial, superfosfato triple (SFT, que tenía una concentración de 53,2 mg de Cd por kg de fertilizante. La dosis de fertilizante aplicada fue la necesaria para alcanzar un nivel de 30 mg kg-1 de POlsen. Los suelos se incubaron en estufa durante 90 días, a 25masculineC y humedad de capacidad de campo. El diseño experimental fue completamente al azar, con tres repeticiones para cada suelo y donde la unidad experimental fue un contenedor con 250 g de suelo seco. Se midió Cd disponible a los 1, 2, 7, 14, 21, 36, 49, 63, 77 y 90 días después de la incubación. La aplicación de P en dosis agronómica, utilizando fertilizante con alto contenido de Cd, tuvo un efecto estadísticamente significativo sobre la concentración de Cd disponible en los suelos estudiados, sin embargo, no hubo efecto del tiempo de incubación en la disponibilidad de Cadmio.

Remoción de partículas adsorbentes de iones cobre por flotación Jet

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Santander, M.

2009-10-01

Full Text Available The present study shows the results obtained on the removal of copper ions from synthetic effluents by using the adsorbent particles flotation technique (APF in a Jet flotation cell (Jameson type. In a typical experimental run, a mineral with high quartz content was used as adsorbent particles in the adsorption and flotation experiments, to determine optimal pH conditions, adsorbent particles concentration; flotation reagents dosage and air/effluent flow ratio for applying in the Jet cell to maximize the efficiency of copper ions adsorptions and the removal of particles adsorbent containing the absorbed copper ions. The results indicate that at pH > 7 and at adsorbent particles concentration of 2 kg.m^–3, 99 % of copper ions is adsorbed and, when the air/ effluent flow ratio applied in the Jet cell is 0.2, 98 % of adsorbent particles containing the adsorbed copper ions is removed.

Los resultados que se presentan en este artículo corresponden a los estudios realizados para la remoción de iones cobre desde efluentes sintéticos, utilizando la técnica de flotación por partículas adsorbentes (FPA en una celda de flotación Jet (tipo Jameson. En los estudios de adsorción y flotación se utilizó, como partículas adsorbentes, mineral con alto contenido de cuarzo, para determinar condiciones óptimas de pH, concentración de partículas adsorbentes, dosis óptimas de reactivos de flotación, razón flujo de aire/flujo de efluente necesaria de aplicar en la celda Jet, para maximizar la eficiencia de adsorción de iones cobre y remoción de partículas adsorbentes de iones cobre. Los resultados indican que, a pH > 7 y concentraciones de partículas adsorbentes de 2 kg.m^–3, se adsorbe el 99 % de los iones cobre y cuando la razón flujo de aire/flujo de efluente, aplicada en la celda Jet, es 0,2, se remueve un 98 % de las partículas adsorbentes de iones cobre.

Adsorción de plomo y cadmio en sistema continuo de lecho fijo sobre residuos de cacao

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Jose Lara; Candelaria Tejada; Angel Villabona; Alfonso Arrieta; Clemente Granados Conde

2016-01-01

Se evaluó el desempeño de la cáscara de cacao como material residual adsorbente de metales pesados (Plomo y Cadmio) en solución acuosa sintética, mediante un sistema continuo de lecho fijo. El trabajo experimental consistió en determinar el efecto de la altura del lecho en la remoción de estos contaminantes, manteniendo constantes parámetros como el pH, velocidad de flujo y concentración inicial de los metales. Las pruebas de adsorción presentaron una remoción de 91,32 y 87,80%...

Recuperación de iones cobre por flotación con amilxantato de potasio

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Ramírez-Serrano, B.

2012-08-01

Full Text Available In this paper a study about the column flotation process of copper ion employing potassium amylxanthate as collector reagent is carried out. The effect on the recovery of copper ion by the modification of variables such as collector/metal relation and surface velocity of gas and liquid was determined experimentally by the analysis of the statistic-mathematical model of the copper flotation process, as well as the physico-chemical phenomena that take place, showing the effect of the collector/metal relation in the process. The effect of pH as the main properties of the chemical system in the recovery and the kinetic of the flotation process is made too. The experimental results shows that the recovery of copper in the pH range of 4,5 - 12 is possible with prevalence of precipitate flotation.

Se realiza un estudio sobre la flotación en columnas de iones cobre utilizando como reactivo colector amilxantato de potasio. Se determina experimentalmente el efecto de la modificación de las variables relación colector/metal, velocidad superficial del gas y del líquido sobre la recuperación, a partir del análisis del modelo matemático-estadístico que caracteriza la flotación de cobre, así como de los fenómenos físico-químicos que tienen lugar, donde se comprueba el papel preponderante de la variable relación colector/metal en la recuperación de cobre. Se estudia además, el efecto del pH como elemento determinante de las características químicas del sistema en la recuperación y la cinética del proceso de flotación. Los resultados experimentales muestran que es posible la recuperación del cobre disuelto para el rango de pH de 4,5 a 12 con predominio de la flotación de precipitados.

LIXIVIACION BACTERIANA EN REACTORES: RECUPERACION DE COBRE A PARTIR DE CONCENTRADOS SULFURADOS.

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CASAS DE PRADA, JESUS MANUEL

1991-01-01

Se estudió la cinética de lixiviación química (estéril) y bacteriana (con Thiobacillus ferrooxidans) de dos concentrados sulfurados de cobre, utilizando como agente oxidante el sulfato férrico en ambos casos. Los concentrados fueron suministrados por las 167p.

Heavy metal profile of water, sediment and freshwater cat fish, Chrysichthys nigrodigitatus (Siluriformes: Bagridae, of Cross River, Nigeria

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Ezekiel Olatunji Ayotunde

2012-09-01

sampling area. Most of the heavy metals were below the maximum allowable levels set by the WHO, FEPA and USEPA, except Zinc which mean concentration of 0.099±0.00404μg/g was above the recommended limit of 0.0766μg/g of USEPA in the sediment at Ikom. This implies that the waste assimilation capacity of the river is high, a phenomenon that could be ascribed to dilution, sedimentation and continuous water exchange. This is an indication that an urban and industrial waste discharged into the Cross River has a significant effect on the ecological balance of the river. Thus fish species from the Cross River harvested are safe for human consumption.Cross River funciona como una fuente importante de agua potable, transporte, actividades agrícolas y pesqueras en el Estado Cross River, Nigeria. Dado que no existe un control formal de los efluentes vertidos en el río, es importante monitorear los niveles de metales contaminantes en el mismo, por lo tanto la evaluación de su idoneidad para el uso doméstico y agrícola. Para la determinación de lo anterior, tres estaciones de muestreo designadas como Ikom (Estación I, Obubra Ogada (Estación II y Calabar (Estación III fueron seleccionadas al azar para el estudio. Se tomaron diez muestras de “Bagre de agua dulce de plata” (Chryshchythys nigrogitatus de 29.4-39.5cm LE (longitud estándar y 310-510g de peso, sedimentos y agua fueron recolectadas en cada estación de muestreo de junio 2009 a junio 2010. Los perfiles de metales pesados de Zn, Cu, Fe, Co, Pb, Cd y Cr, en agua, sedimentos y músculos de peces fueron analizados por espectrofotometría de absorción atómica (AAS. En los peces, la concentración de metales pesados que se determinó fue Cu>Fe>Zn>Cu>Pb>Cd>Co, para los peces se determinó una mayor concentración media de cobre (0.297±0.022g/g, cadmio (0.011±0.007μg/g, hierro (0.371±0.489μg/g y plomo (0.008±0.008μg/g. En el agua, el orden se determinó como sigue: Fe>Pb>Zn>Cu>Cr>Cd>Co, con una mayor

Dinámica del cadmio en suelos cultivados con papa en Nariño, Colombia. Dinamic of the cadmium in soils cultivated with potatoes in Nariño, Colombia

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Liliana Insuasty B

2008-01-01

Full Text Available Se evaluó la fijación y movilidad de cadmio en suelos dedicados al cultivo de papa en Túquerres, Pasto y Guachucal. Se tomaron muestras de suelos no disturbadas en cilindros de PVC, las cuales, luego de aplicaciones fraccionadas de cadmio con dosis de 0, 50,100 y 150 ppm, se incubaron a capacidad de campo durante cuatro meses. En estos suelos los contenidos de cadmio total e intercambiable no sobrepasaron los límites permisibles establecidos por Organización Mundial de la Salud-Organización de las Naciones Unidas para la Agricultura y la Alimentación (OMS-FAO; no obstante, la mayor cantidad del elemento se localizó en la parte superior de los núcleos, lo cual indica baja movilidad del elemento en el perfil.The mobility of cadmium and fixation in soils cropped with potatoes in Túquerres, Pasto and Guachucal Nariño, Colombia was evaluated. Samples with an auger of 11 cm diameter and 40 cm in length were taken. On these soil samples applications of 0, 50, 100 and 150 ppm cadmium were, and incubated during a 4 month period under field capacity. In this soils the content of total exchangeable cadmium do not overcome the permissible limits established by World Health Organization-Food and Agriculture Organization of the United Nations. The highest concentration of cadmium applied in the for of total Cd and changeable Cd was found in the higher third part of cores, which indicates a low mobility of the element in the soil profile.

Glicinato de cobre: una aproximación a su solubilidad

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Gloria Elena Tobón Zapata

2009-04-01

Full Text Available Se estudian los isómeros cis y trans del glicinato de cobre, como parte de un proyecto que pretende elaborar un suplemento nutricional con oligoelementos esenciales, considerando los factores que afectan la disolución y por lo tanto, la biodisponibilidad de los complejos. Con el fin de encontrar, en una etapa temprana de la formulación, una relación entre el proceso de disolución y algún parámetro de medida independiente del tamaño de partícula, se evalúan los descriptores: circularidad, diámetro de feret, área, perímetro y dimensión fractal. Los que menor variación presentan son: circularidad y dimensión fractal, esta última puede relacionarse con el proceso de disolución calculando 2 propiedades relacionadas: la dimensión fractal superficial y la dimensión fractal reactiva. Este trabajo demuestra que en los complejos de glicinato de cobre a mayor tamaño de partícula la velocidad de disolución es mayor si existen grietas en la superficie, lo que se evidencia en una dimensión fractal reactiva mayor que .una dimensión fractal superficial.

Exportación de nibs de cacao nativo de fino aroma con niveles de cadmio <= 0.5 mg/kg

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Santa Cruz Muñoz, Iris Magaly

2016-01-01

La tesis expone un plan de negocios que surge a raíz de la demanda creciente internacional del cacao debido a una demanda de un chocolate con mayor contenido de cacao, la cual debe satisfacer normas sociales, saludables, ecológicas y éticas del cual el Perú es reconocido como país productor de Cacao de Fino Aroma. Asimismo, existe la amenaza que tienen los productores latinoamericanos de cacao por haberse encontrado altos niveles de cadmio en granos de cacao, siendo este perjudicial para la s...

Las ciudades del cobre: Del campamento de montaña al hotel minero como variaciones de la company town

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Eugenio Garcés

2003-12-01

Full Text Available Este artículo analiza las "ciudades del cobre" en Chile, asentamientos ex-novo construidos a lo largo del siglo XX por empresas internacionales. De manera complementaria a los territorios rurales y las ciudades tradicionales, fueron diseñadas para atender funciones productivas, residenciales y de equipamiento, con el propósito de alcanzar resultados de eficiente producción. El artículo presenta cuatro casos relacionados con la Corporación del Cobre (CODELCO, entidad estatal formada en 1971, luego de la nacionalización del cobre en Chile, y otros dos casos vinculados con la minería privada. Ponen de manifiesto la evolución experimentada por los asentamientos -desde la ciudad minera hasta el hotel minero- a partir de criterios productivos que incluyen operaciones territoriales, urbanas y arquitectónicasThis paper analyses the copper mining ex-novo settlements in Chile, built during the XX century by international enterprises. As a complement to the rural territory and the traditional cities, they attend productive functions, residence necessities and other facilities, with the purpose to obtain efficient production. The paper presents four cases that belongs to the Corporación del Cobre (CODELCO, the State enterprise organized in 1971, and other two cases related to the private enterprises. They show the evolution of the settlements, from the mining town to the mining hotel, based on productive criteria that include territorial, urban and architectural operations

Citotoxicidad del cadmio en hepatocitos de ratón albino y sus posibles implicaciones en ambientes tropicales

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Letty Marcano; Clarisa de R. Faría; Ingrid Carruyo; Xiomara Montiel

2006-01-01

Se realizó un análisis de las alteraciones fenotípicas, estructurales y ultraestructurales inducidas por Cd+2 en hepatocitos de ratón albino suizo. El metal fue suministrado vía oral en solución acuosa de CdCl2 durante 100 días a concentraciones de 50 ppm, 100 ppm y 150 ppm, en los controles la solución de cadmio fue sustituida por agua destilada. Las muestras fueron procesadas utilizando la técnica de inclusión en parafina y teñidas con hematoxilina- eosina para microscopía óptica y por la t...

Copper distribution in leaves and roots of plants growing on a copper mine-tailing storage facility in northern Chile Distribución de cobre en hojas y raíces de plantas que crecen sobre relaves mineros de cobre en el norte de Chile

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CLAUDIA ORTIZ-CALDERÓN

2008-12-01

Full Text Available In a copper mine-tailing afforested we characterized the physicochemical properties of the substrate at vegetated and non-vegetated patches. We studied the accumulation of copper in roots and leaves of the species present at the site, to evaluate their phytoextraction and/or phytostabilization potential. The non-vegetated mine-tailing substrate showed a high contení of metals, mainly copper (> 2.5 g kg-1, a pH 7.4, high contení of salts and 5.0 % organic matler. Vegelaled palches al íhe lailing showed similar characlerislics of pH, salís and organic maller conlenl, and showed a lolal copper concenlralion lower íhan íhe conlenl found ai íhe non-vegelaled patches. Nine plant species present at the site were screened for copper accumulation and distribulion in rools and leaves, and polenlial for copper phyloexlraclion or phyloslabilizalion was suggesled. The nalive species Schinus polygamus and Atriplex deserticola, accumulaled over 1.2 g kg-1 copper in íheir leaves, showing íhal íhey are pseudomelallophyles for íhe melal. Five of íhe nine plañí species sludied were considered suilable for phyloexlraclion procedures and four were apt for phytostabilization of copper polluted sites. By making a screening of species growing on a copper polluted site, we were able to select plants adapted lo semi-arid environmental conditions and suitable for mine-tailings remediation purposes.En un tranque de relaves previamente forestado, se realizó una caracterización fisicoquímica del sustralo en sectores vegetados y no vegetados. Se esludió la acumulación de cobre en raíces y hojas de las especies présenles en el sitio de trabajo, con el objeto de evaluar su potencial fitoextractor y fitoestabilizador. El sustrato del sector no vegetado presentó un pH 7,4; altos contenidos de sales y 5,0 % de materia orgánica, además de un alto contenido de metales pesados, principalmente cobre (> 2,5 g kg-1. Los sectores vegetados del tranque de relaves

Intoxicação aguda por cobre em ovinos

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Marcele Bettim Bandinelli

2013-10-01

Full Text Available Descrevem-se casos de intoxicação aguda por cobre em ovinos da raça Santa Inês, numa propriedade rural, no Rio Grande do Sul. Três ovelhas recém-paridas, que consumiam ração formulada para bovinos, ingeriram, avidamente, sal mineral comercial para bovinos e apresentaram doença clínica e morte, uma semana após a introdução do sal. Os animais desenvolveram anorexia, permaneceram em decúbito lateral, o qual evoluiu para esternal e apresentaram fasciculação e rigidez muscular generalizada, antes de morrerem. À necropsia de um desses animais, as principais alterações foram hepatomegalia moderada e acentuação do padrão lobular hepático, além de erosões e ulcerações multifocais aleatórias na mucosa abomasal. Na avaliação histológica do fígado, havia necrose hepatocelular centrolobular acentuada e difusa, tumefação de hepatócitos, predominantemente, na região periportal, além de pequena quantidade de células de Kupffer com pigmento granular citoplasmático. O diagnóstico baseou-se na história clínica, nos achados de necropsia e histopatológicos e confirmou-se pelas altas concentrações de cobre detectadas no tecido hepático e nas amostras de ração e sal mineral.

Estudio de electrodeposición de cobre sobre electrodos porosos de grafito y acero inoxidable vía SEM-DRX y análisis de imagen

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Constanzo-R., Robinson; Pagliero-N., Antonio; Vergara-G., Froilán

2014-01-01

El objetivo de este trabajo fue realizar un análisis cualitativo de la distribución de un electrodepósito de cobre en el interior de electrodos porosos (EP) de acero inoxidable y carbono grafito. Para ello, se realizaron pruebas de electrodepositación de cobre a nivel de laboratorio, con un posterior análisis de cortes de muestras de acero y grafito vía Microscopía Estereoscópica, Microscopía SEM-DRX y Análisis de Imagen, los cuales mostraron que el cobre no se deposita en forma uniforme al i...

Recuperación de cobre en escorias mediante biolixiviación indirecta

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Mazuelos, A.

2009-06-01

Full Text Available The main source of copper loss from a smelter is copper in discard slag. Slag can contain Cu in concentrations very much higher than those of many ores. Cu is present in slag entrained in very small drops of matte, white metal and blister copper occluded in fayalitic phase. In this work, the technical viability of the BRISA process, that is based on the indirect bioleaching, for this residue has been proved. A sample of slag, containing 2 % of copper, has been chemical, granulometrical and metallographic characterized and it has been leached with ferric sulphate solutions in agitated reactors. The influence of several variables have been investigated. Once the best operating conditions had been selecting and an economic estimation had been done (with very really attractive results, the leaching stage has been designed for a plant of 30 tonnes per hour capacity. Cu extractions higher than 70% can be achieved with a residence time of only five hours. Despite of Cu(II concentration in fed is as high as 30 g/l, biooxidation stage can supply Fe(III demanded by ferric leaching stage.

En los procesos pirometalúrgicos, parte del cobre se pierde en la escoria que se genera como residuo del proceso, pudiendo estar presente en ella, en concentraciones muy superiores a las de muchas menas. El cobre se encuentra formando parte de pequeñas partículas de mata, metal blanco y blister, ocluidas en fase de fayalita. En este trabajo se ha probado la viabilidad técnica del proceso BRISA, que está basado en la biolixiviación indirecta, para el tratamiento de este residuo. Se ha caracterizado una escoria con un 2 % en cobre, desde los planos químico, granulométrico y metalográfico. Este material se ha lixiviado con disoluciones de sulfato férrico en reactores agitados, estudiándose el efecto de diversas variables. A partir de los resultados obtenidos, e incluyendo un estudio económico, con resultados muy atractivos, se han seleccionado las mejores

Preliminary observations of cadmium and copper effects on juveniles of the polychaete Capitella sp. Y (Annelida: Polychaeta from Estero del Yugo, Mazatlán, México Observaciones preliminares de los efectos de cadmio y cobre sobre juveniles del poliqueto Capitella sp. Y (Annelida: Polychaeta del Estero del Yugo, Mazatlán, México

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NURIA MÉNDEZ

2005-12-01

Full Text Available The effects of cadmium (Cd and copper (Cu on cultured juveniles of Capitella sp. Y were investigated. Seven-day old juveniles were exposed to 13 (control, 60, 160, 240 and 340 mg Cd L-1 and 17 (control, 50, 120 and 150 mg Cu L-1 for 30 days. Mortality significantly increased with increasing Cu concentrations, but in Cd exposures, it was only evident at 340 mg L-1. Body size and faecal pellet production were reduced earlier in juveniles exposed to Cu than those exposed to Cd, especially in the higher Cu concentrations. These facts indicate that juveniles are more sensitive to Cu in terms of mortality, feeding and growth. Haemoglobin production was inhibited due to the scarcity of food in the experimental sediment rather than to metal exposure. Tube building was not affected by the presence of metals or by the scarcity of food. This study suggests that Cu concentrations from 50 to 150 mg L-1 and 340 mg L-1 of Cd could affect the population dynamics of this species in natural ecosystemsSe investigaron los efectos de cadmio (Cd y cobre (Cu sobre juveniles cultivados de Capitella sp. Y. Organismos juveniles de siete días de edad fueron expuestos a 13 (control, 60, 160, 240 y 340 mg Cd L-1 y a 17 (control, 50, 120 y 150 mg Cu L-1 durante 30 días. La mortalidad se incrementó significativamente al aumentar las concentraciones de Cu y, en las exposiciones a Cd, solamente fue evidente a 340 mg L-1. El tamaño corporal y la producción de heces fecales disminuyeron antes en los especímenes expuestos a Cu que en los expuestos a Cd, especialmente en las concentraciones más altas de Cu. Estos resultados indican que los juveniles son más sensibles al Cu en términos de mortalidad, alimentación y crecimiento. La producción de hemoglobina fue inhibida debido a la escasez de alimento en el sedimento experimental, más que a exposición a los metales. La formación de tubos no fue afectada por la presencia de metales ni por la escasez de alimento. Este

Niveles de plomo y cadmio en agua marina y lapas (Patella vulgata L.) de la Ría de Vigo

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M. Pérez López; M.C Nóvoa; J. Alonso; M. A. García Fernández; M.J. Melgar

2003-01-01

El empleo de seres vivos para monitorizar la contaminación por metales pesados en los ecosistemas acuáticos es de extremo interés en el campo de la ecotoxicología. En el presente estudio se han recogido muestras de agua marina y de lapas (Patella vulgata L.) de distintos puntos de la Ría de Vigo, con la intención de determinar en ellos los niveles de plomo y cadmio, por medio de una técnica de voltamperometría. Los resultados obtenidos mostraron una relación estrecha entr...

Determinación de la adsorción de cadmio mediante isotermas de adsorción en suelos agrícolas venezolanos

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Subero Neudis

2011-06-01

Full Text Available El cadmio es un metal pesado que tiende a acumularse en la superficie del suelo. En los últimos años,las actividades antropogénicas han ocasionado un incremento en los niveles de este metal en suelosagrícolas generando gran preocupación ambiental debido a su movilidad y lixiviación en el perfil delsuelo y a la facilidad con que es absorbido por las plantas. El objetivo de este trabajo fue determinarla capacidad de adsorción de cadmio, de cuatro suelos venezolanos de uso agrícola con diferenciastexturales. Para determinar la capacidad de adsorción del metal en cada suelo, inicialmente se determinóel tiempo óptimo de agitación; el cual fue de 2 horas y la relación suelo-solución enriquecedora de Cd;la cual fue de 1:50. Con estos parámetros se elaboraron las isotermas de adsorción para los suelos y secompararon los modelos de Freundlich y Langmuir. Los resultados mostraron que el modelo matemáticode Freundlich es el que mejor describe la cinética de la reacción y la capacidad de adsorción de Cdpor los suelos, siendo los que poseen mayores contenidos de arcilla, MO y pH ácidos los de mayorcapacidad de adsorción.

Síntesis y Caracterización de Ag2Cu2O3, el primer óxido de cobre y plata

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Gómez-Romero, P.

2000-06-01

Full Text Available Despite the crystal-chemical similarities between copper and silver ions, there is no known silver copper oxide, neither natural nor synthetic. In this work, we present the synthesis at room-temperature of the first silver copper oxide of formula Ag2Cu2O3 (tetragonal, a=5.8857(3Å, c=10.6868(7Å, space group I41/amd, Z=4. It should be noted that the thermal stability of this new oxide is enhanced with respect to Ag2O or even CuO. The structure consists of alternating chains of edge-sharing square planar Cu(II and zigzag chains of linearly coordinated Ag(I ions.A pesar de las similitudes cristaloquímicas entre los iones de cobre y los de plata, no existe ningún óxido mixto de cobre y plata ni natural ni sintético. En este trabajo se presenta la síntesis a bajas temperaturas del primer óxido mixto de cobre y plata, de fórmula Ag2Cu2O3 (tetragonal, a=5.8857(3Å, c=10.6868(7Å, grupo espacial I41/amd, Z=4. Este óxido posee una estabilidad térmica superior a los correspondientes óxidos de cobre y de plata. Contiene cadenas de iones Cu(II cuadrado-planos que alternan con cadenas en zig-zag de Ag(I con coordinación lineal.

Dinamic of the cadmium in soils cultivated with potatoes in Nariño, Colombia Dinámica del cadmio en suelos cultivados con papa en Nariño, Colombia.

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Burbano Orjuela Hernán

2008-03-01

Full Text Available The mobility of cadmium and fixation in soils cropped with potatoes in Túquerres, Pasto and Guachucal Nariño, Colombia was evaluated. Samples with an auger of 11 cm diameter and 40 cm in length were taken. On these soil samples applications of 0, 50, 100 and 150 ppm cadmium were, and incubated during a 4 month period under field capacity. In this soils the content of total exchangeable cadmium do not overcome the permissible limits established by World Health Organization–Food and Agriculture Organization of the United Nations. The highest concentration of cadmium applied in the for of total Cd and changeable Cd was found in the higher third part of cores, which indicates a low mobility of the element in the soil profile.Se evaluó la fijación y movilidad de cadmio en suelos dedicados al cultivo de papa en Túquerres, Pasto y Guachucal. Se tomaron muestras de suelos no disturbadas en cilindros de PVC, las cuales, luego de aplicaciones fraccionadas de cadmio con dosis de 0, 50,100 y 150 ppm, se incubaron a capacidad de campo durante cuatro meses. En estos suelos los contenidos de cadmio total e intercambiable no sobrepasaron los límites permisibles establecidos por Organización Mundial de la Salud–Organización de las Naciones Unidas para la Agricultura y la Alimentación (OMS–FAO; no obstante, la mayor cantidad del elemento se localizó en la parte superior de los núcleos, lo cual indica baja movilidad del elemento en el perfil.

Reproducción de Eisenia foetida en suelos agrícolas de áreas mineras contaminadas por cobre y arsênico.

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ÁVILA, G.; GAETE, H.; MORALES, M.; NEAMAN, A.

2008-01-01

El objetivo del trabajo fue evaluar la toxicidad del cobre y arsénico en suelos agrícolas, mediante bioensayos estandarizados de toxicidad aguda y crónica sobre Eisenia foetida y relacionar la respuesta de ésta con las concentraciones de cobre y arsénico en los suelos. Los suelos agrícolas fueram muestreados en las inmediaciones de áreas mineras en la cuenca del río Aconcagua, Chile. E. foetida expuesta a los suelos estudiados mostró una baja mortalidad, indicando la ausencia de toxicidad agu...

Diseño de complejos binucleares de cobre en estudios biomiméticos de la tirosinasa.

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Rolando Calero

2015-10-01

Full Text Available Se ha estudiado la reactividad de ciertos metaloenzimas de cobre y algunos complejos de Cobre sintéticos que presentan reactividad frente a sustratos, a través de la interacción con el oxígeno molecular, además se ha observado en las varias formas en como ocurre esta interacción y la razón por la cual  porque unos actúan con el oxigeno para ser transportadores como las Hemocianinas y otros formando aductos para mediar reacciones químicas hacia ciertos sustratos fenólicos. También se propone una revisión de los mecanismos para la hidroxilación de fenoles y la oxidación a quinonas, encontrando una dependencia atribuible a factores estéricos y redox en la unión catalizador-sustrato.

Determinación de la adsorción de cadmio mediante isotermas de adsorción en suelos agrícolas venezolanos

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Nereida Sánchez

2011-04-01

Full Text Available El cadmio es un metal pesado que tiende a acumularse en la superficie del suelo. En los últimos años, las actividades antropogénicas han ocasionado un incremento en los niveles de este metal en suelos agrícolas generando gran preocupación ambiental debido a su movilidad y lixiviación en el perfil del suelo y a la facilidad con que es absorbido por las plantas. El objetivo de este trabajo fue determinar la capacidad de adsorción de cadmio, de cuatro suelos venezolanos de uso agrícola con diferencias texturales. Para determinar la capacidad de adsorción del metal en cada suelo, inicialmente se determinó el tiempo óptimo de agitación; el cual fue de 2 horas y la relación suelo-solución enriquecedora de Cd; la cual fue de 1:50. Con estos parámetros se elaboraron las isotermas de adsorción para los suelos y se compararon los modelos de Freundlich y Langmuir. Los resultados mostraron que el modelo matemático de Freundlich es el que mejor describe la cinética de la reacción y la capacidad de adsorción de Cd por los suelos, siendo los que poseen mayores contenidos de arcilla, MO y pH ácidos los de mayor capacidad de adsorción.

Intoxicação crônica por cobre em ovelhas pastoreadas em pomar de videiras adubado com cama aviária

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Luiz Alberto Oliveira Ribeiro

2007-06-01

Full Text Available No presente trabalho é relatado caso de intoxicação crônica por cobre (ICC ocorridos em rebanho ovino pastoreados em pomar de videiras, na serra Gaúcha; suplementados com bagaço de uva e concentrado. O pomar era aspergido anualmente com solução de sulfato de cobre a 2% e teve seu solo adubado com cama aviária. Os ovinos mostraram andar cambaleante, icterícia intensa das mucosas e urina escura, dos quais foram a óbito oito animais, correspondendo a 57% do total do rebanho. Os sinais clínicos e lesões histológicas foram características da ICC. A dosagem de Aspartato Aminotrasferase (AST no soro dos seis ovinos remanescentes variou de 48,8 a 403,3 UI/L. O nível de cobre encontrado na cama aviária, bagaço de uva, pastagem e concentrado foram de 637, 158, 86 e 18 mg/kg respectivamente. Conclui-se que os óbitos ocorreram devido ao alto nível de cobre encontrado na pastagem, bagaço de uva e concentrado administrado aos animais. Sugere-se também, o risco de dano ambiental no uso de cama aviária na adubação de pastagem, assim como a inadequação da alimentação de ovinos com bagaço de uva.

Determinación de los niveles de plomo y cadmio en leche procesada en la ciudad de Bogotá D.C.

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Pinzon Choque, Carlos Giovanni

2015-01-01

La leche y los productos lácteos han sido reconocidos en todo el mundo por su influencia beneficiosa sobre la salud humana. Los niveles de metales en concentraciones tóxicas son un componente importante de la seguridad y la calidad de la leche. Se desarrolló un método sencillo de extracción (digestión) asistida por microondas para la determinación posterior de los niveles de cadmio (Cd) y plomo (Pb) en leche líquida por espectrofotometría de absorción atómica (AAE) con horno de grafito. Se ap...

Biosorción de iones cobre con biomasa de algas y orujos deshidratados

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Romero, L.

2011-02-01

Full Text Available They were carried out experiments of biosorption batch and in continuous to remove copper from aqueous solutions using as adsorbent green algae and olive residues under virgins conditions and chemically activated. The results of batch biosorption indicate that the algae present mayor elimination capacities than the waste of olives, with uptakes of copper of the order of 96 % using activated algae with dissolution of Na₂SO₄ under the optimum conditions. The results of the columns tests show that the virgin algae permits the removal of more copper ions than the activate algae, with removal efficiency of 98 % during the firth 20 min, a breakthrough time of 240 min and a saturation at time of 600 min. In the second cycle the regenerated biomass showed a best performance indicating that they can be used for another biosorption cycle.

Se realizaron experimentos de biosorción batch y en continuo para remover cobre desde soluciones acuosas usando como adsorbentes algas verdes y residuos de aceituna en condiciones vírgenes y activadas químicamente. Los resultados de la biosorción a escala batch indican que las algas presentan mayor capacidad de eliminación que los orujos, alcanzándose captaciones de cobre del orden de 96 % con algas activadas con disoluciones de Na₂SO₄ bajo condiciones óptimas de las variables estudiadas. Los resultados de los ensayos en columna muestran que las algas vírgenes captan más iones cobre que las activadas con Na₂SO₄, con eficacias de eliminación del 98 % durante los primeros 20 min, con un tiempo de ruptura de 240 min y una saturación a los 600 min. Al ser sometidas a un segundo ciclo de biosorción, las algas regeneradas muestran un mejor rendimiento lo que indica que pueden ser usadas en otro ciclo de eliminación.

Estudio isotérmico de biosorción de cromo y cadmio en solución acuosa utilizando residuos de césped

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Andrango Caizapanta, Daniel Xavier

2012-01-01

A nivel mundial la contaminación con metales pesados ha dejado una triste secuela de tragedias ecológicas de gran impacto sobre el ambiente global. Por citar un caso: en el año de 1998 en Coto de Donana, aproximadamente un millón de metros cúbicos de lodos que contenían cadmio y otros metales terminaron en el río Guadimar afectando significativamente los sensibles lugares de reproducción aviar. En el Ecuador la situación no es menos alarmante, por ejemplo, en un estudio r...

Concentração de cobre e molibdênio em algumas plantas forrageiras do Estado do Mato Grosso do Sul

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Flávio Prada

1998-01-01

Full Text Available Foi realizado um levantamento sobre as quantidades de cobre e molibdênio contidas em quatro gramíneas - Capim colonião (Panicum maximum, Jaraguá (Hyparrhenia rufa (Ness Stapf, Pangola (Digitaria decumbens Stent e Angolinha (Eriochloa polystachya (H.B.K. Hitchc - colhidas mensalmente durante um ano, no município de Brasilândia, Mato Grosso do Sul, Brasil. Os valores médios encontrados foram, para o cobre: 4,46 e 3,63 para o capim Colonião, 4,13 e 3,50 para o Jaraguá, 5,21 e 3,65 para o Pangola e 5,10 e 4,09 para o Angolinha, respectivamente na época das "águas" e das "secas". Para o molibdênio, os valores médios encontrados foram de 14,43 e 12,65 para o Colonião, 13,03 e 13,83 para o Jaraguá, 12,33 e 13,20 para o Pangola e 12,45 e 12,88 para o Angolinha, respectivamente nas épocas das "águas" e das "secas". Não houve diferenças consideradas significativas entre capins tanto para o cobre como para o molibdênio, no período de 12 meses de colheita.

Evaluación ambiental del río San Juan de Santiago de Cuba por exposición bioacumulativa a metales pesados Environmental evaluation of San Juan river in Santiago de Cuba due to bioaccumulative exposure to heavy metals

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George Argota Pérez

2012-08-01

Full Text Available Se evaluó la salud ambiental del río San Juan de Santiago de Cuba, expuesto a metales pesados, mediante la utilización de la especie biorreguladora Gambusia punctata. Se analizaron 271 individuos adultos clasificados por sexo, para lo cual se escogieron los intervalos de clases de edades 2,1-3,0 y 3,1-4,0 cm, según la longitud total, respectivamente. La mezcla ácida aplicada estuvo compuesta por ácido perclórico - ácido sulfúrico; (7:1 ácido nítrico para determinar los niveles bioacumulados en hígado, branquias y cerebro como órganos diana. Los metales analizados: cobre, zinc, plomo y cadmio, se cuantificaron mediante espectrometría por plasma inductivamente acoplado con vista axial. Se hallaron diferencias significativas (pThe environmental health of San Juan river in Santiago de Cuba, exposed to heavy metals was evaluated by means of the bioregulatory species Gambusia punctata. Two hundred and seventy five adults were analyzed and classified by sex, for whom the intervals of age classes 2.1-3.0 and 3.1-4.0 cm were chosen, according to the total longitude, respectively. The applied acid mixture was composed by perchloric acid - sulphuric acid; (7:1 nitric acid to determine the bioaccumulated levels in liver, branchiae and brain as target organs. The analyzed metals: copper, zinc, lead and cadmium, were quantified by means of spectrometry by plasma inductively coupled with axial view. There were significant differences (p <0.05 in the bioaccumulated values between intervals and sexes. It was concluded that the levels of bioaccumulated heavy metals overcame the permissible values, so that they represent an environmental risk in the quality of those waters.

Adsorción de metales pesados en andisoles, vertisoles y ácidos húmicos

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Luis Enrique Cortés Páez

2015-01-01

Full Text Available Se estudió la adsorción de los metales pesados cadmio (Cd, cobre (Cu, níquel (Ni, plomo (Pb y zinc (Zn en Andisoles (Typic Melanudand y Vertisoles (Epiaquert ústico arcilloso fino isohipertérmico 1% de Colombia y en ácidos húmicos (AH extraídos de muestras de leonardita tomadas en España. En todos los casos se determinaron las propiedades químicas y físicas: pH, capacidad de intercambio catiónico (CIC, carbono orgánico (%CO, bases intercambiables y contenido total de metales. La composición química de los AH se determinó empleando técnicas espectrométricas como ICP_MS, FTIR, UV-Vis, CPMAS 13C NMR y Py-GC/MS-THMA. Los resultados de adsorción de los metales ajustados al modelo de Freundlich mostraron un comportamiento diferente de los adsorbentes en relación con los metales estudiados, siendo la máxima capacidad de adsorción (K y la fuerza de retención (n de los metales diferente (P Pb > Cu > Ni > Zn; en Andisol: Pb > Cu > Cd > Zn > Ni; y en Vertisol: Cd > Pb > Cu > Ni > Z. Para n en ácidos húmicos: Pb > Zn > Cd > Cu > Ni; en Andisol: Cu > Ni > Zn > Pb > Cd, y en Vertisol: Zn > Ni > Cu > Pb > Cd.

Alterações metabólicas e funcionais do cobre em diabetes mellitus Metabolic and functional alterations of copper in diabetes mellitus

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Lucia de Fátima Campos Pedrosa

1999-12-01

Full Text Available O objetivo desta revisão foi discutir aspectos que envolvem as alterações metabólicas e funcionais do cobre em Diabetes Mellitus. Na presença desta doença, alguns distúrbios funcionais de cobre têm sido caracterizados e explicados em parte por alterações nos processos de absorção, circulação e utilização do elemento. O estado hormonal pode modificar a secreção biliar de cobre e assim repercutir na regulação homeostática da absorção. A redução na atividade da lisil-oxidase, uma cuproenzima, altera a síntese de colágeno e de elastina, comprometendo assim a integridade dos vasos sangüíneos. Tal fato pode agravar o desenvolvimento de complicações vasculares nos diabéticos. Os estudos com diabetes experimental apontam um acúmulo tecidual de cobre nos rins, o que conduz à especulações quanto à gênese da nefropatia diabética. Os experimentos com pacientes diabéticos demonstram irregularidades no cobre circulante, aumento de peroxidação lipídica e estado nutricional inadequado deste micronutriente.The aim of this review was to discuss aspects that involve metabolic and functional alterations of copper in Diabetes Mellitus. In this disease some functional disturbances of copper have been explained by alterations in the processes of absorption, circulation and utilization of this element. The hormone status can modify the biliary secretion of copper and therefore to reflect on homeostatic regulation of the absorption. Impaired lysil oxidase activity (a kind of cuproenzyme alters elastin and collagen synthesis and this damages the integrity of the blood vessel. This fact can worsen the development of the vascular alterations in diabetic patients. Researches with experimental diabetes indicate high concentrations of copper in kidneys. This leads to speculations about the genesis of the diabetic nephropathy. Human studies demonstrate that diabetic patients have abnormal circulation of copper, lipid peroxidation

Influencia de la adición de cobre y de bronce sobre las propiedades de los aceros inoxidables austeníticos sinterizados

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Velasco, F.

1997-04-01

Full Text Available The effect that, on AISI 316L and 304L stainless steels alloyed with copper and bronze in different percentages up to a maximun of 20 % wt, produce both the alloying content and the sintering temperature over physical and mechanical properties and over the microstructure of sintered stainless steels are studied. Alloying with copper and bronze improves the density of sintered steels at the two sintering temperatures used. Copper and bronze promote liquid phase sintering (transitory or permanent, that activates sintering process. Tensile strength of stainless steel is highly improved for higher alloying contents. Moreover, tensile strength presents greater values alloying with bronze than with copper.

Partiendo de los aceros inoxidables AISI 316L y 304L a los que se añadió cobre y bronce en diferentes porcentajes hasta el 20 % en peso, se estudia el efecto que la cantidad de aleante y la temperatura de sinterización tienen sobre las propiedades físicas y mecánicas y sobre la microestructura de los aceros inoxidables sinterizados. La aleación con cobre y con bronce aumenta la densidad de los aceros sinterizados para las dos temperaturas de sinterización utilizadas. El cobre y el bronce provocan la aparición de fase líquida (transitoria o permanente que activa el proceso de sinterización. La resistencia a la tracción del acero inoxidable experimenta un fuerte incremento para los contenidos más elevados de aleante. Además, la resistencia a la tracción alcanza mayores valores para la aleación con bronce que con cobre.

Determinación de las causas del rajado del fruto de uchuva (Physalis peruviana L. bajo cubierta. II. Efecto de la oferta de calcio, boro y cobre

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Cooman Alexander

2005-06-01

Full Text Available

Se evaluo la incidencia del rajado del fruto de uchuva, cultivada en macetas y bajo invernadero, con presencia y ausencia en la fertilizacion de los elementos calcio, cobre y boro, y sus interacciones. Los rendimientos en cosecha se redujeron por la ausencia de calcio y cobre pero el boro no incidio en este aspecto. El peso de los frutos individuales aumento por la ausencia del boro en la fertilizacion, mientras que la ausencia del calcio produjo frutos de menor peso y el cobre no incidio en este aspecto. En el tratamiento de fertilizacion completa, que incluyo todos los elementos, el rajado fue mas importante en las primeras semanas y menor hacia el final del periodo de cosecha. El rajado del fruto se expreso en funcion de la presencia de calcio y boro en la fertilizacion, con un incremento de 5,5 a 13% de frutos rajados cuando cualquiera de los dos era eliminado de la solucion nutritiva. El cobre no tuvo efecto sobre la incidencia del rajado. El tamano del fruto, aunque significativo, incidio poco sobre la ocurrencia del rajado.

Optimización de parámetros de deposición de capas delgadas de cobre utilizando diseño de experimentos

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Shirkavand, Nazanin

2013-01-01

Una investigación, denominada Optimización de parámetros de deposición de capas delgadas de cobre utilizando diseño de experimentos y desarrollada en el Centro de Investigación en Ciencia e Ingeniería de Materiales (CICIMA), de la Universidad de Costa Rica, tuvo como objetivo poder encontrar la relación de los parámetros del magnetrón (presión, potencia y tiempo) con el grosor de formación de las capas delgadas de cobre. Se utilizó el método estadístico de 2K (donde K es el número de parámetr...

Respuesta metalúrgica de fracciones finas de minerales sulfurados de cobre en un proceso combinado de flotación modificada y biolixiviación agitada

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Ibáñez, J. P.

2007-04-01

Full Text Available The metallurgical behavior of fine fractions of copper sulfide minerals of Compañía Minera Quebrada Blanca S.A. was studied by concentration through flotation in aqueous media modified by alcohol followed by bioleaching of the concentrates. By using a 1 % v/v of methanol, the metallurgical recovery of copper reaches 88 %, while the iron recovery was 43 %, the weight recovery was 18%, which indicates a high selectivity. These concentrates were then bioleached with and without nutrient medium, reaching 80 % of copper recovery after 10 and 17 days, respectively. Then, it is possible to conclude that this concentration-bioleaching metallurgical process is a promising route for copper recovery from the fine fraction of sulfide minerals.

Se estudió la respuesta metalúrgica de la fracción fina, 100 % -100 # ASTM, de un mineral sulfurado de cobre de la Compañía Minera Quebrada Blanca S.A., sometido a una etapa de concentración mediante flotación en medio acuoso modificado (FEMAM® con metanol y la posterior biolixiviación agitada de este concentrado. Al emplear un 1 % v/v de metanol se logran los mejores resultados: una recuperación metalúrgica de cobre y hierro de 88 y 43 %, respectivamente, y una recuperación en peso del 18 %. Lo cual indica una alta selectividad de este tipo de flotación para especies sulfuradas de cobre. El concentrado FEMAM® fue posteriormente sometido a una etapa de biolixiviación agitada en ausencia y presencia del medio nutriente 9 K, lográndose el 80 % de extracción de cobre a los 17 y 10 días, respectivamente. Esto permite concluir que una ruta de concentración-biolixiviación es una alternativa tecnológica apropiada para procesar la fracción fina de minerales sulfurados de cobre.

Overview of the nutritional status of selected micronutrients in Mexican children in 2006 Estado nutricional de algunos micronutrientes en niños mexicanos en 2006

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Teresa Shamah-Levy

2012-04-01

Full Text Available OBJETIVE: To present an overview of micronutrient status of Mexican children in 2006. MATERIALS AND METHODS: Data on iron, zinc, folate and vitamin B12 deficiencies and low serum copper and magnesium were gathered and critically analyzed from the 2006 National Health and Nutrition Survey. RESULTS: Iron deficiency is still the main nutritional deficiency in children (13%-26%. Zinc deficiency was high in all age groups (≈25% but reduced 5.6 PP in children OBJETIVO: Presentar un panorama del estado de micronutrimentos de niños mexicanos en 2006. MATERIAL Y MÉTODOS: Los datos sobre deficiencias de hierro, zinc, folatos, vitamina B12 y concentraciones bajas de cobre y magnesio se analizaron a partir de la Encuesta Nacional de Salud y Nutrición 2006. RESULTADOS: La deficiencia de hierro fue la más importante en niños (13-26%. La deficiencia de zinc fue alta en todos los grupos de edad (≈25% y disminuyó entre 1999 y 2006 5.6 pp en niños. La deficiencia de folatos fue de 3.2% y la de vitamina B12 de 7.7%. Las concentraciones bajas de magnesio y cobre fueron altas (22.6 y 30.6%, respectivamente. CONCLUSIONES: La deficiencia de hierro pareció disminuir y la de zinc se redujo en niños mexicanos. La alta prevalencia de deficiencias de cobre y magnesio merecen más investigación para entender sus implicaciones en salud pública.

Respuesta de ecotipos de Stylosanthes capitata a dosis de cobre en solución nutritiva

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Pizarro Esteban A.

1986-09-01

Full Text Available La solución nutritiva de Arnon y Hoagland se modificó a 1/10 para simular las condiciones de acidez y fertilidad del suelo de las sabanas bien drenadas isohipertérmicas de los Llanos Orientales de Colombia. Se usaron seis concentraciones de cobre (0,0.05, 0.1, 0.2, 0.4 Y 0.8 ppm. la solución nutritiva se renovó cada 15 días y se aplicaron nitrógeno (14 ppm/semana e hierro (1 ppm, 3/semana. La cantidad de materia seca producida por los ecotipos y el cultivar Capica en los tratamientos de 0.2, 0.4 Y0.8 ppm Cu, fue relativamente te nula. La producción de materia seca de la parte aérea, raíz y total de la planta fue diferente en los ecotipos de S capitata. Así mismo hubo diferencias significativas en la concentración, absorción y translocación del cobre por lo ecotipos y el cultivar Capica. El requerimiento diferencial de cobre, manifestado en la producción de materia seca en la parte aérea en el nivel 0.05 ppr por los ecotipos CIAT 1693 y 1728 por el cultivar Capica (CIAT 102801, se define como el resultado de las relaciones evolutivas de cada ecotipo con el nivel de cobre disponible en la solución del suelo.In the greenhouse ecotypes of Stylosanthes capitata were cultivated to observe their behavior under different copper concentrations. A nutrient solution based on Arnon and Hoagland's (1/10 was used to simulate the acidity and the fertility of well drained savannas of the Eastern Planes of Colombia. Six concentrations of copper were used (O, 0.05, 0.1, 0.2, 0.4 and 0.8 ppm with rewal of the nutrient solution every 15 days, and applications of nitrogen (14 ppm/week and iron (1 ppm, three times/week. The dry matter quantity produced by the ecotypes and the Capica cultivar under treatments of 0.2, 0.4 and 0.8 ppm Cu, relatively nill. A differential behavior of Stylosanthes capitata ecotypes responses to applied copper was observed in relation to dry matter production in aerial, part, root and total plant. So, there were significant

Proteinograma e teores de cobre, ferro e zinco no soro sanguíneo de ovelhas da raça Santa Inês com mastite experimental por Staphylococcus aureus Proteinogram and serum concentrations of copper, iron and zinc in Santa Inês ewes with Staphylococcus aureus experimentally induced mastitis

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Nivaldo de Azevêdo Costa

2010-05-01

Full Text Available Este estudo teve por objetivo avaliar o proteinograma e os teores de cobre, ferro e zinco no soro sangüíneo de ovelhas com mastite induzida por cepa de campo de Staphylococcus aureus. Foram utilizadas 10 ovelhas da raça Santa Inês, primíparas, recém-paridas, com aproximadamente dois anos de idade e bom estado nutricional. Inoculou-se na metade direita da glândula mamária 1,0x10(4 UFC/mL da bactéria, enquanto que a metade esquerda serviu como controle. Os animais foram acompanhados diariamente e a partir do diagnóstico clínico de mastite, procedeu-se colheita do material para realização do proteinograma sérico em gel de poliacrilamida contendo dodecil sulfato de sódio (SDS-PAGE e para determinação do teor plasmático de fibrinogênio e das concentrações séricas de cobre, ferro e zinco em 16 momentos a saber: antes da inoculação (controle e 12h, 24h, 36h, 48h, 60h, 72h, 84h, 96h, 108h, 120h, 132h, 168h, 180h, 288h e 336h após a inoculação (p.i.. Todas as ovelhas apresentaram quadro clínico de mastite, com perda da funcionalidade da glândula mamária. O proteinograma permitiu a identificação de 23 proteínas, cujos pesos moleculares (PM variaram de 26.000 a 185.000 dáltons (Da, incluindo proteínas de fase aguda, IgG e IgA. Notou-se aumento significativo nas concentrações de haptoglobina e ceruloplasmina, assim como de IgG e IgA. Não se constatou alteração nos teores de antitripisina e de glicoproteína ácida .Verificou-se diminuição nos teores de ferro e zinco e elevação na concentração de cobre. Constatou-se correlação positiva entre o teor plasmático de fibrinogênio e as concentrações séricas de ceruloplasmina (r=0,74, a haptoglobina (r=0,62 e IgA(r=0,62. Estes resultados mostram a importância das proteínas de fase aguda ceruloplasmina e haptoglobina como indicadores auxiliares da infecção intramamária de ovelhas, assim como ratifica a relevância do fibrinogênio como marcador inflamat

Deficiência de cobre em suínos: caracterização clínico-patológica

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Karla Moraes Rocha Guedes

2014-07-01

Full Text Available São relatados dois casos de deficiência de cobre em suínos (A e B, fêmeas, sem raça definida, de três meses de idade, provenientes de propriedade rural em Planaltina, GO. Os animais apresentavam incoordenação, paresia de membros pélvicos, com progressão para os membros torácicos e andar com flexão da articulação metacarpo-falangeana. Na propriedade de origem dos animais, outros dois suínos apresentavam atrofia da musculatura da coxa e posição sentada quando parados. O rebanho recebia dieta não-balanceada constituída por milho, soro de leite e sobras de lavoura. Na necropsia, não foram observadas alterações significativas, mas histologicamente havia vacuolização periaxonal multifocal no tronco encefálico e na medula espinhal, quantidade discreta de esferoides axonais e macrófagos no interior dos vacúolos. A coloração com azul rápido de luxol (ARL para mielina demonstrou que as áreas de vacuolização caracterizavam focos de desmielinização. Amostras de fígado dos dois suínos apresentaram níveis de cobre muito abaixo do normal, de 13,1 partes por milhão (ppm (suíno A e 5,7ppm (suíno B. Este trabalho descreve dois casos de desmielinização medular e de tronco encefálico devido à deficiência de cobre em suínos jovens.

Concentración por flotación de menas de oro-cobre con bajas recuperaciones de arsénico

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Chacón, L.

2005-12-01

Full Text Available The present work evaluates the reagents and appropriate conditions in order to obtain flotation concentrates with high copper content and low arsenic recovery. The studied ore is a blend of 80 % w/w El Valle ore and 20 % w/w Carlés ore, this latter being rich in copper and arsenic content. Those ores are worked from two deposits located in Asturias-Spain and treated at a concentration plant nearby. The arsenic content in the floated concentrate is penalized by the buyer. The main conclusion from the study is that a dithiophosphate is the collector that provides the best results, what was confirmed at plant-scale.

El objetivo del presente trabajo es definir los reactivos y las condiciones apropiadas para obtener concentrados con alta ley de cobre y baja recuperación de arsénico, a partir de muestras de una mezcla con 80 % en peso de una mena de oro, cobre y bismuto, y 20 % en peso de otra mena rica en oro y cobre, pero con alta ley de arsénico, provenientes de los yacimientos El Valle y Carlés, ubicados en Asturias-España, y procesados en una planta de concentración. La presencia de arsénico en el concentrado flotado es penalizada por sus compradores. La principal conclusión del trabajo es que un ditiofosfato como único reactivo colector es el que logra alcanzar el objetivo planteado, lo que se comprobó con pruebas en la planta de concentración.

EFECTO DEL COBRE SOBRE LA REPRODUCCIÓN EN NOVILLAS LECHERAS DE CUBA

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Juan García D

2006-12-01

Full Text Available Objetivo. Evaluar el efecto del cobre sobre el comportamiento reproductivo de novillas lecheras.Materiales y métodos. El trabajo se realizó en fincas de la provincia de Villa Clara, en dos etapasy con 210 novillas. En la primera se estudiaron 120 novillas divididas en dos grupos de 60 animalescada uno. El grupo A, control y el B, tratado con 2 ml de CuSO4 (2.5% subcutáneamente. En lasegunda etapa se estudiaron 90 novillas divididas en tres grupos de 30 animales cada uno, elgrupo A, control; el B, fue tratado con 2 ml de CuSO4 (2.5% subcutáneamente y el grupo C, setrató con acupuntura utilizando 0.1 ml de dicho producto subcutáneamente en el punto Pahuai; enambas etapas los animales del grupo A, no recibieron ningún tratamiento y a los animales tratados,grupos B y C se les repitió el tratamiento cada 60 días en dos aplicaciones más. Los análisishemoquímicos se efectuaron en los laboratorios de la Facultad de Ciencias Agropecuarias de laUniversidad Central de Las Villas. Resultados. Los animales aumentaron significativamente los nivelesdel cobre en suero sanguíneo (p<0.05, así como los porcentajes de presentación de celo y degestaciones con el consiguiente beneficio económico. Conclusión. La aplicación de la cuproterapiatanto alopática como acupunturalmente incrementó la cupremia y la fertilidad de las hembrasbovinas tratadas.

Adsorção de cobre em amostras de Plintossolo do Estado do Piauí, com diferentes características Copper adsorption in Plinthosol samples from Piauí State, Brazil, with different characteristics

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Lúcia H. G. Chaves

2009-06-01

Full Text Available A capacidade de adsorção de cobre pelo solo é um dado importante em estudos de movimentação de solutos uma vez que, se a capacidade adsortiva de um solo for ultrapassada, o metal ficará potencialmente disponível para ser lixiviado. Neste trabalho se analisam o comportamento da adsorção de cobre face às diferentes características de amostras de Plintossolo e a influência da variação de pH na adsorção do cobre, verificando-se a adequação das equações de Langmuir e Freundlich para descrever a adsorção deste elemento. Soluções de cloreto de cobre foram utilizadas nas concentrações 6, 10, 20, 40, 60 e 80 mg L-1 ajustadas a pH 4,0, 5,0 e 6,0. Os teores de matéria orgânica e a capacidade de troca catiônica das amostras de solo compõem as propriedades que mais influenciaram na adsorção do cobre. Os modelos de Langmuir e Freundlich mostraram-se igualmente capazes para descrever o comportamento do cobre nas diferentes amostras de solo estudadas. A adsorção do cobre variou em função do pH ocorrendo maior adsorção no pH 6,0.Copper adsorption by soil is very important, as after soil adsorptive capacity is exceeded, the metal become potentially available for leaching. The objectives of this study were to analyze copper adsorption considering different properties of soil samples studied, to evaluate the influence of the pH level on copper adsorption and to verify if Langmuir and Freundlich isotherms describe adequately the copper adsorption. Solutions containing different copper concentrations (6, 10, 20, 40, 60 e 80 mg L-1 were adjusted to pH 4.0, 5.0 and 6.0. The organic matter content and cation exchange capacity were the soil properties that most influenced copper adsorption. Langmuir and Freundlich models offered a good fit for the experimental data. Copper adsorption varied with soil pH, with greater adsorption at pH 6.0.

Materiales e innovación en arquitectura sanitaria: cobre, barrera antibacteriana para espacios sanitarios = Materials and innovation in sanitary architecture: copper, antibacterial barrier for sanitary spaces

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Paula Aillón García

2017-12-01

Full Text Available La inclusión del cobre como material antibacteriano en la arquitectura sanitaria ayuda a resolver la gran paradoja que existe en los servicios asistenciales; entrar a servicios de salud para sanarse de una enfermedad puntual y adquirir enfermedades de riesgo de muerte. Esta investigación demuestra la eficacia del cobre en formato laminar en vez de sólido, haciendo mediciones de
 con luminometría, abriendo un camino factible para el cobre como revestimiento antibacteriano y dotando de su propiedad antibacteriana superficial a costos reducidos, sin necesidad de cambios de mobiliario ni obras Abstract The inclusion of copper as an antibacterial material in health architecture helps to solve the great paradox that exists in healthcare services; enter health services to heal from a specific illness and acquire life-threatening diseases. This research demonstrates the effectiveness of copper in laminar format instead of solid, making measurements of ATP with luminometry, opening a feasible way for copper as an antibacterial coating and endowing its superficial antibacterial property at reduced costs, without the need for furniture changes or works.

Temporal trending of lead and cadmium contamination in the Vigo estuary intertidal area Evolución temporal de la contaminación por plomo y cadmio en la zona intermareal de la ría de Vigo

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J. Alonso Díaz

2004-12-01

Full Text Available At the present work, limpet (Patella vulgata L. and seaweed (Ulva lactuca specimens have been monthly sampled at the same point from the Vigo estuary, during a year. Heavy metal (cadmium and lead content has been determined by means of differential pulse anodic stripping voltammetry in both limpet and seaweed tissues, as well as in seawater. The obtained results have shown the main heavy metal content in limpet soft tissues with respect to shell, with maximum concentrations of 3 ppm (limpet shell for lead, whereas the highest content for cadmium was identified in seaweed samples (1.1 ppm. The statistical study revealed the existence of a clear correlation between cadmium and lead concentrations in seaweed samples.En el presente trabajo se han recogido muestras de lapa (Patella vulgata L. y alga verde (Ulva lactuca en un mismo punto de muestreo de la ría de Vigo, con una periodicidad mensual, a lo largo de un año, analizándose por medio de voltamperometría de redisolución anódica la concentración en dos metales pesados con claras repercusiones toxicológicas, cadmio y plomo, en estas muestras, así como en el agua marina. Los resultados obtenidos mostraron la mayor concentración de ambos metales en los tejidos blandos de las lapas frente a las valvas de estos moluscos, con valores máximos en el caso del plomo próximos a 3 ppm (valva de lapa, mientras que para el cadmio se situó en torno a 1,1 ppm (alga verde. El estudio estadístico permitió poner en evidencia una clara correlación estadística entre los valores de cadmio y plomo cuantificados en las muestras de algas.

Enfermedades profesionales en la industria del cobre: extracción, manufactura y reciclaje

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C.D. Cabrera-Marutz; S. Velásquez-Alcalá; J. Vrhovac-Biljesko

2014-01-01

Introducción: El cobre por sus características se utiliza en una gran variedad de aplicaciones en la industria energética, sus múltiples usos unidos a la expansión y evolución de los diversos sectores industriales lo hacen una pieza fundamental para lograr el desarrollo sostenible de la sociedad actual. La minería, procesamiento, reciclaje y su transformación genera riqueza, crea puestos de trabajo y a su vez puede suponer un riesgo potencial para el desarrollo de enfermedades profesionales. ...

Acumulación de cobre y alteraciones histopatológicas en el ostión Crassostrea angulata

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2005-01-01

Full Text Available Ejemplares de ostión Crassostrea angulata fueron expuestos a concentraciones subletales de cobre (200 y 600 µg L–1 Cu2+ durante un periodo de 2 a 30 días. Se cuantificó la concentración de cobre, así como las alteraciones histopatológicas inducidas en branquias, glándula digestiva y corazón. Las concentraciones más elevadas de cobre correspondieron a las branquias, con valores alrededor de 2 mg g–1 peso seco en los organismos expuestos a la concentración más alta, al final del periodo de exposición (día 30. En la glándula digestiva la concentración alcanzada fue del orden de 1 mg g–1 peso seco. La tasa de bioconcentración (BCr, definida como la diferencia entre la concentración en el tejido a una concentración de exposición a tiempo t y la concentración media del control a lo largo del experimento, dividida por el tiempo de exposición, disminuyó en ambos tejidos. Los valores variaron en el intervalo entre 392 y 57 µg g–1 d–1 en las branquias y entre 133 y 18 µg g–1 día–1 en la glándula digestiva. En branquias de ejemplares tratados con una concentración de 200 µg L–1 Cu2+ se observó una desorganización del tejido conjuntivo, alteraciones en la porción apical de las células ciliadas e hiperplasia y fusión de laminillas, pudiendo llegar incluso a la pérdida de estas laminillas a 600 µg L–1 Cu2+. En la glándula digestiva (hepatopáncreas de ejemplares sometidos a 600 µg L–1 Cu2+ se detectó un adelgazamiento del epitelio y, en algunos casos, oclusión de la luz de los túbulos digestivos y dilatación de los conductos digestivos. En el corazón de los organismos expuestos a concentraciones subletales de cobre se observó un adelgazamiento del epitelio de las aurículas y del ventrículo, un incremento de las células marrones (brown cells en las paredes de las aurículas, así como una distensión de las fibras musculares y destrucción del tejido conectivo de soporte, tanto en las aur

Silicose em ex-mineiros de extração de cobre Silicosis among former copper mine workers

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Fernanda de Freitas Luz

2011-08-01

Full Text Available Existe escassez de estudos brasileiros analisando o efeito da exposição contínua à sílica em ex-trabalhadores de minas de cobre. Os achados radiográficos produzidos pela silicose têm recebido atenção médica especial. O objetivo deste estudo foi caracterizar clinica e radiologicamente a silicose em ex-mineiros de extração de cobre. Foi feito um estudo transversal com 100 ex-mineiros de extração de cobre. Os itens foram coletados através de entrevista pessoal, dados clínicos ocupacionais e foram realizados exames radiológicos. Na entrevista foi verificada a idade, o sexo e o tempo de trabalho na extração de cobre. Os pacientes que já realizaram exame radiológico de tórax trouxeram estes para comparação. Os mineiros assinaram um termo de consentimento para realização dos exames radiológicos o qual foi aplicado pelo radiologista que os interpretou. Entre os 100 ex-mineiros, 35% são portadores de silicose, 11% apresentaram alterações pulmonares que podem ter outras causas, como tuberculose, enfisema e doença broncopulmonar obstrutiva crônica, e 54% não apresentaram nenhuma alteração pulmonar. A alta freqüência de silicose encontrada reforça a recomendação de suspender a exposição à sílica tão logo se tenha uma radiografia sugestiva da doença.There is a dearth of Brazilian studies analyzing the effect of ongoing exposure to silica among former copper mine workers, as radiographic readings for silicosis have received widespread medical attention. The scope of this study is to investigate the clinical and radiological manifestations of silicosis among former copper mine workers. A sample of 100 former copper miners had their clinical and occupational histories recorded and underwent chest radiography in a cross-sectional study that included personal interviews in which their age, sex and time worked in copper extraction were recorded. Patients with recent chest X-Rays brought them with them, or they signed a

Utillaje faunístico inédito de las labores de cobre prehistóricas de La Profunda (León y su datación C14 (AMS

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Miguel Angel de BLAS CORTINA

2010-08-01

Full Text Available La mina de La Profunda, en Leon, hace decenios que se reconoce como un espacio minero prehistorico genericamente atribuido a la Edad del Bronce merced a la aparicion de varias hachas de cobre (nunca debidamente descritas y hoy desaparecidas, una extrana pieza del mismo metal y los caracteristicos, aunque cronoculturalmente ambiguos, percutores elaborados con cantos rodados. La localizacion reciente de utiles en materia animal (en asta y tibia de Cervus elaphus, ademas de un cuerno de Capra hircus procedentes de la mina permite no solo el conocimiento de una modalidad instrumental bien documentada en las expresivas minas de cobre de la cercana Asturias (labores prehistoricas del Aramo y El Milagro sino tambien la datacion radiocarbonica que situa los trabajos extractivos de La Profunda ya en la segunda mitad del milenio III a.C. La alta rentabilidad de aquel venero de cobre hubo de proporcionar mineral y metal a sociedades de un ambito bastante mayor que el correspondiente al sector montanoso donde las minas se abren, alcanzando a las comunidades aldeanas de la Edad del Cobre (el llamado “Horizonte las Pozas” en las tierras sedimentarias de la meseta septentrional de Castilla, y tambien, probablemente, a las autoras de los poblados amurallados por entonces existentes en el sector sudoeste de la dilatada cuenca hidrografica del Duero.

The extraction of zinc and other minor metals from concentrated ammonium chloride solutions with D2EHPA and Cyanex 272

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Amer, S.

1995-12-01

Full Text Available A comparative study is made of the extractants D2EHPA and Cyanex 272 for the zinc and minor metal extraction from aqueous concentrated ammonium chloride solutions, as those of the leaching liquors of the CENIM-LNETI process. Extraction equilibrium data for zinc are presented as extraction isotherms at constant pH and at a temperature of 50 °C. Zinc extraction and coextraction of minor metal ions as Cu, Ca, Pb, Mg, Cd, Co, Ni and Hg are studied. Mercury does not extract from concentrated ammonium chloride solutions. Cyanex 272 shows a better selectivity for zinc with regard to the minor metals than D2EHPA, which is especially remarkable for calcium, the most coextracted element by D2EHPA. Nickel and cadmium coextraction is negligible for both extractants. The possible use of the Cyanex 272 as an alternative to D2EHPA is considered.

Se realiza un estudio comparativo del comportamiento del D2EHPA y del Cyanex 272 durante la extracción del cinc y otros metales minoritarios de soluciones acuosas concentradas de cloruro amónico, como las de las soluciones de lixiviación del proceso CENIM-LNETI. Se presentan los datos de equilibrio de extracción del cinc en forma de isotermas de extracción a una temperatura de 50 °C y pH constante y se estudia la coextracción de los metales minoritarios Cu, Ca, Pb, Mg, Cd, Co, Ni y Hg. El mercurio no se extrae de las soluciones concentradas de cloruro amónico. La selectividad del Cyanex 272 para el cinc respecto de esos metales minoritarios es mejor que la del D2EHPA, siendo verdaderamente notable para el calcio, que es la impureza que más se coextrae con el D2EHPA. La coextracción de níquel y de cadmio es muy pequeña para ambos extractantes. Se considera la posibilidad del uso alternativo del Cyanex 272 en lugar del D2EHPA.

Cuantificación de plomo, cadmio y cromo mediante sialoquímica Quantification of lead, cadmium and chromium through sialochemistry

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MIREYA GONZÁLEZ

1997-05-01

Full Text Available Objetivo. Determinar las concentraciones de plomo, cadmio y cromo, y establecer su posible asociación con diferentes factores sociodemográficos. Material y métodos. Se seleccionó una muestra representativa de 100 estudiantes de posgrado de la Facultad de Odontología de la Universidad Nacional Autónoma de México (UNAM, a los cuales se les colectó saliva total no estimulada. Dichas muestras fueron analizadas por espectrofotometría de absorción atómica con horno de grafito. Resultados. Metales pesados como el plomo, el cadmio y el cromo se encuentran en concentraciones mucho más altas que las informadas en la literatura: Pb, = 3.10 m g/dL-1, máxima: 16.8 my g/dL-1, y mínima: 0.04 my g/dL-1; Cd, = 0.25 my g/dL-1, máxima: 2.04 my g/dL-1, y mínima: 0.004 my g/dL-1; y Cr, = 1.43 my g/dL-1, máxima: 4.82 my g/dL-1, y mínima: 0.05 my g/dL-1. Asimismo, variables como la zona de residencia, el sexo, la edad y la ingesta de comida enlatada no influyen en los niveles de plomo y cromo. Sin embargo, en el caso del cadmio y la edad existe una asociación inversa (ji²= 5.9012, pObjective. To determine the concentration of lead (Pb, cadmium (Cd, and chromium (Cr and establish the possible association of these heavy metals with some sociodemographic factors. Material and methods. A representative sample of one hundred dental students from the National Autonomous University of Mexico living in Mexico City participated in this study. Unstimulated human whole saliva samples were analyzed by Atomic Absorption Spectroscopy. Results. Concentrations of Pb, Cd, and Cr were higher than those reported elsewhere: Pb ( or = 3.10 m g/dL-1; Maximum: 16.8 mu g/dL-1 and Minimum: 0.04 mu g/dL-1, Cd ( or = 0.25 mu g/dL-1; Maximum: 2.04 mu g/dL-1 and Minimum: 0.004 mu g/dL-1 and Cr ( or = 1.43 mu g/dL-1; Maximum: 4.82 mu g/dL-1 and Minimum: 0.05 mu g/dL-1. No association was found between the variables studied (age, sex, geographic area and canned food consumption

Cementación de oro con polvo de cinc en soluciones de lixiviación con amoniaco-tiosulfato

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Navarro, R

2005-02-01

Full Text Available The cementation of gold with powder of zinc, from solutions with thiosulphate and ammonia, was studied. The variables evaluated were: thiosulphate concentration, ammonia concentration, pH, copper concentration and zinc concentration. The results have revealed the great importance of ammonia/thiosulphate relationship in this process and that the impurities presence like copper and zinc will to inhibit the cementation process.

Se estudió la cementación de oro con polvo de cinc desde soluciones con tiosulfato y amoniaco, evaluando la influencia de las siguientes variables: concentración de tiosulfato, concentración de amoniaco, pH, concentración de cobre y concentración de cinc. Los resultados han permitido establecer la gran importancia que tiene, en este proceso, la relación amoniaco/tiosulfato y cómo la presencia de impurezas como cobre y cinc inhiben el proceso de cementación.

The influence of green microstructure and sintering parameters on precipitation process during copper-nickel-zinc ferrites sintering

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Barba, Antonio

2014-04-01

Full Text Available Microstructural changes that occur during heat treatment of copper-nickel-zinc ferrites have been studied. The process of precipitation of the two types of crystals that occur during the sintering process has been analyzed. It is found that this process depends on dry relative density of the press specimens and on the following sintering parameters: sintering temperature, sintering time and cooling rate of the thermal cycle. Crystal precipitates characterization have been done by scanning electron microscopy (SEM, energy-dispersive X-ray (EDX analysis, X-ray diffraction (XRD, and X-ray photoelectron spectroscopy (XPS. These techniques have allowed to determine the nature of these crystals, which in this case correspond to zinc and copper oxides. It has been used two chemical reactions to explain the bulk precipitation and subsequent re-dissolution of these crystal precipitates during sintering.En este trabajo se han estudiado los cambios microestructurales que se producen durante el tratamiento térmico de las ferritas de cobre-níquel-cinc y se ha analizado el proceso de precipitación de los dos tipos de cristales que aparecen durante el proceso de sinterización. Se ha encontrado que este proceso depende de la densidad relativa en seco de las muestras compactadas y de las siguientes variables de la etapa de sinterización: temperatura y tiempo de sinterización y velocidad de enfriamiento. La caracterización de los cristales precipitados se ha realizado por microscopía electrónica de barrido (MEB, microanálisis por dispersión de energía de rayos X (EDX, difracción de rayos X (DRX, y espectroscopía de fotoelectrones de rayos X (XPS. Estas técnicas han permitido determinar la naturaleza de estos cristales, que en este caso corresponden a los óxidos de cinc y de cobre. Se han propuesto dos reacciones químicas que permiten explicar el proceso de precipitación y la posterior re-disolución de estos cristales precipitados durante la

Zinc fingers, zinc clusters, and zinc twists in DNA-binding protein domains

International Nuclear Information System (INIS)

Vallee, B.L.; Auld, D.S.; Coleman, J.E.

1991-01-01

The authors recognize three distinct motifs of DNA-binding zinc proteins: (i) zinc fingers, (ii) zinc clusters, and (iii) zinc twists. Until very recently, x-ray crystallographic or NMR three-dimensional structure analyses of DNA-binding zinc proteins have not been available to serve as standards of reference for the zinc binding sites of these families of proteins. Those of the DNA-binding domains of the fungal transcription factor GAL4 and the rat glucocorticoid receptor are the first to have been determined. Both proteins contain two zinc binding sites, and in both, cysteine residues are the sole zinc ligands. In GAL4, two zinc atoms are bound to six cysteine residues which form a zinc cluster akin to that of metallothionein; the distance between the two zinc atoms of GAL4 is ∼3.5 angstrom. In the glucocorticoid receptor, each zinc atom is bound to four cysteine residues; the interatomic zinc-zinc distance is ∼13 angstrom, and in this instance, a zinc twist is represented by a helical DNA recognition site located between the two zinc atoms. Zinc clusters and zinc twists are here recognized as two distinctive motifs in DNA-binding proteins containing multiple zinc atoms. For native zinc fingers, structural data do not exist as yet; consequently, the interatomic distances between zinc atoms are not known. As further structural data become available, the structural and functional significance of these different motifs in their binding to DNA and other proteins participating in the transmission of the genetic message will become apparent

Efecto de los componentes del agua de mar durante el fenómeno de corrosión por picaduras del cobre

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García, E.

1995-10-01

Full Text Available Copper is the main component in Cu-Ni alloys recommended for sea water applications. This work presents the electrochemical behaviour of copper in presence of different sea water components and its influence on the corrosion attack. The combined action of chloride and sulphate ions are the main responsible factor for the localized corrosion attack in the form of pitting. A significant parabolic relation exists between the critical pitting potential (E_p and the weight ratio of chloride to sulphate (Cl^-/SO₄^2- ions. Therefore sulphate ions are an important component for pitting corrosion of copper.

El cobre es el elemento principal de las aleaciones Cu-Ni recomendadas para aplicaciones marinas. En este trabajo se presenta el comportamiento electroquímico del cobre con los diferentes componentes del agua de mar y el efecto de estos sobre la forma de ataque del cobre. Se observó que los iones cloruro, en unión con los iones sulfato, son los principales causantes del fenómeno de corrosión por picaduras, existiendo, además, una relación significativa entre el potencial crítico de picado (E_p y la relación (Cl^-/SO₄^2- de tipo parabólico, lo cual pone de manifiesto la importancia del ion sulfato en el fenómeno de corrosión por picaduras como promotor de este tipo de mecanismo.

Novel Co(III)/Co(II) mixed valence compound [Co(bapen)Br2]2[CoBr4] (bapen = N,N‧-bis(3-aminopropyl)ethane-1,2-diamine): Synthesis, crystal structure and magnetic properties

Science.gov (United States)

Smolko, Lukáš; Černák, Juraj; Kuchár, Juraj; Miklovič, Jozef; Boča, Roman

2016-09-01

Green crystals of Co(III)/Co(II) mixed valence compound [Co(bapen)Br2]2[CoBr4] (bapen = N,N‧-bis(3-aminopropyl)ethane-1,2-diamine) were isolated from the aqueous system CoBr2 - bapen - HBr, crystallographically studied and characterized by elemental analysis and IR spectroscopy. Its ionic crystal structure is built up of [Co(bapen)Br2]+ cations and [CoBr4]2- anions. The Co(III) central atoms within the complex cations are hexacoordinated (donor set trans-N4Br2) with bromido ligands placed in the axial positions. The Co(II) atoms exhibit distorted tetrahedral coordination. Beside ionic forces weak Nsbnd H⋯Br intermolecular hydrogen bonding interactions contribute to the stability of the structure. Temperature variable magnetic measurements confirm the S = 3/2 behavior with the zero-field splitting of an intermediate strength: D/hc = 8.7 cm-1.

Avaliação do metabolismo oxidativo e da histopatologia renal e hepática de ovinos intoxicados por cobre e tratados com tetratiomolibdato e vitaminas antioxidantes

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Rebeca Alves Weigel

2008-01-01

Para avaliar o benefício da utilização parenteral das vitaminas C e/ou E associadas ao quelante de cobre, tetratiomolibdato de amônio (TTM), na recuperação de ovinos com intoxicação cumulativa por cobre (ICC), foram analisados os parâmetros vitais; o metabolismo oxidativo, através das concentrações séricas de ácido úrico e malondialdeído, atividade sanguínea da glutationa reduzida, habilidade de redução férrica plasmática, atividade urinária de N-acetil-β-D-glucosamidase; peso vivo, hema...

Estudio de los fundentes utilizados en la metalurgia del cobre en Cerro Muriano (Córdoba durante el período Romano Altoimperial

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Criado, A. J.

1996-10-01

Full Text Available There are no doubts that Hispania was, under the Roman Empire, the most profitable and abundant in resources of all the mining districts exploded by Rome -Hispania, Galia, Danubian Provinces, Dacia, Greece, Asia Minor, Syria, Egypt and North Africa-. Plinius gives the same data and hands many more in the passages dedicated to the mining and the working of the metals in his Natural History. Of all the many mining places that this author refers, the exploiting in copper at Cerro Muriano presents the main interest; of this he says that it was of an unbeatable quality, used, among other applications, to manufacture the very famous "Copper of Campania". The utilization of fusing agents, adapted to the process of copper obtainment, is fundamental for obtaining this high quality. The addition of these fusing agents was very important for the control of the work parameters and to reach the required temperatures. The high purity of the obtained copper shows a very close knowledge of the phenomena involved in the process.

Durante el Imperio Romano, de todos los distritos mineros explotados por Roma -Hispania, Galia, las provincias danubianas, Dacia, Grecia, Asia Menor, Siria, Egipto y el Norte de África-, sin duda el más rentable y más abundante en recursos era Hispania. Plinio facilita muchos datos en los pasajes dedicados a la minería y el trabajo de los metales en su Historia Natural. Entre los muchos lugares mineros que este autor cita, nos interesa ahora la explotación de cobre en Cerro Muriano, del cual dice que era de una calidad inmejorable, utilizado, entre otras aplicaciones, para fabricar el famosísimo cobre de Campania. Para poder obtener esta elevada calidad, es fundamental la utilización de fundentes adecuados en el proceso de obtención de cobre. La adición de estos fundentes era vital para controlar los parámetros de trabajo y alcanzar las temperaturas requeridas. La elevada pureza del cobre obtenido demuestra un

Determinación de la concentración de cadmio en un chocolate colombiano con 65% de cacao y chocolates extranjeros con diferentes porcentajes de cacao

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Echeverry, A.; Reyes, H.

2016-01-01

Se evaluó de forma cualitativa y cuantitativa la presencia de cadmio en un chocolate amargo con 65% de cacao producido en Colombia y en chocolates extranjeros con diferentes porcentajes de cacao. Para la preparación de las muestras se tomaron 0,5 gramos y se realizó una digestión ácida con ácido nítrico concentrado (HNO3 65%). La determinación del metal se llevó a cabo por medio de la técnica de espectrofotometría de absorción atómica de llama (FAAS). Se determinó el límite de detección (LOD)...

Cadmium cytotoxicity in albino mice hepatocytes and its possible implications on tropical environments; Citotoxicidad del cadmio en hepatocitos de raton albino y sus posibles implicaciones en ambientes tropicales

Energy Technology Data Exchange (ETDEWEB)

Marcano, Letty; Carruyo, Ingrid; Montiel, Xiomara [Univ. del Zulia, Facultad Experimental de Ciencias, Dept. de Biologia (Venezuela); com, letty_marcano@hotmail; Faria, Clarisa de R [Univ. del Zulia, Facultad de Medicina, Catedra de Histologia, Maracaibo, Zulia (Venezuela)

2006-06-15

Analyzed phenotypic, structural and ultrastructural alterations induced by Cd{sup +2} in hepatocytes extracted from Swiss Albino mice. Cadmium was given orally in watery solution of CdCl{sub 2} during 100 days at concentrations of 50 ppm, 100 ppm and 150 ppm. In controls, distilled water alone was used. The samples were processed with the paraffin inclusion and hematoxylin-eosin coloration techniques for light microscopy. The conventional technique was used for transmission electron microscopy . Phenotypic (size and weight differences) and physiologic changes (muscular weakness, unrest) were found; at the structural level it was noticed loss of trabecular disposition and of lobular architecture, lymphocyte agglomeration, vacuolisation, dilatation of sinusoid and central vein, among others. The ultrastructural study evidenced alterations coincident with those seen with light microscopy, which were accentuated with the increase of metal concentration: nucleolus with a high number of fibrillar centers (50 ppm); voluminous lipidic drops in the cytoplasm, loose endoplasmic rough reticulum, cytoplasmic vacuolisation, altered lysosomes and peroxisomes (100 ppm); contracted nucleis with condensed chromatin, dilatation of intracellular space and mitochondria, and loss of fibrillar areas (150 ppm). Cadmium produces a toxic effect in the hepatic cells; the effect is more severe at higher concentration, leading to cellular necrosis. (author) [Spanish] Se realizo un analisis de las alteraciones fenotipicas, estructurales y ultraestructurales inducidas por Cd{sup +2} en hepatocitos de raton albino suizo. El Cadmio fue suministrado via oral en solucion acuosa de CdCl{sub 2} durante 100 dias a concentraciones de 50 ppm, 100 ppm y 150 ppm. En los controles la solucion de cadmio fue sustituida por agua destilada. Las muestras fueron procesadas utilizando la tecnica de inclusion en parafina y tenidas con hematoxilina-eosina para microscopia optica y por la tecnica convencional para

Teores de cobre em extratos de carne in natura e processada Copper in meat and thermal meat extracts

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Édira Castello Branco de Andrade Gonçalves

2007-06-01

Full Text Available Especiação química é definida como a determinação da concentração de diferentes formas físico-químicas individuais de um elemento, que em conjunto constitui a concentração total do mesmo, permitindo avaliar o aproveitamento do elemento no processo absortivo. As carnes bovinas e de aves são de grande importância na alimentação, assim, este trabalho tem como objetivo avaliar os teores de cobre em diferentes extratos obtidos pela aplicação da extração seqüencial de carnes in natura, processadas termicamente e congeladas por 30 dias. Os teores de cobre foram determinados através de espectroscopia de absorção atômica. Os dados foram tratados estatisticamente através do teste de Grubs e t de Student. Verificou-se que o cobre encontra-se na maioria das amostras estudadas, em no mínimo duas espécies químicas diferentes. As frações predominantes encontradas foram as representadas pela fração iônica, a qual enfraquece a ligação do metal com compostos orgânicos e sulfetos e promove a dissolução de silicatos e minerais. Observou-se que o processo de cocção e o congelamento diminuem os teores totais e influenciam nas formas químicas do metal. Estudos posteriores que identifiquem estas formas químicas do cobre podem favorecer na avaliação da biodisponibilidade do mesmo.Chemical specification is defined as determining the concentration of different forms of physicist-chemistry individuals of an element, which together consist of the total concentration, and whereby the element in the absorbed process can be evaluated. Beef and chicken are of great importance in food, and therefore the aim of this work was to evaluate copper in different extracts obtained from applying sequential extraction of meat, thermally processed and frozen for 30 days. Copper was determined by using an atomic absorption spectroscopy. The data was dealt with statistically by using the Grubs and t Student test. Copper was found in most of the

Carabalíes y culíes en El Cobre: esclavos africanos trabajadores chinos al servicio del cobre para Swansea, siglo XIX

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Chris Evans

2017-06-01

Full Text Available El objetivo de este artículo es analizar el impacto del Mundo del Cobre en la isla de Cuba hasta el inicio de la segunda mitad del siglo XIX. El estímulo británico producido sobre la minería se expresó en la modernización de las instalaciones, la circulación de capitales y la migración de mano de obra. Respecto a este último punto, la migración transoceánica no solo contempló a los británicos que acudieron a la explotación minera de la isla, sino también dio origen a una reactivación del comercio esclavo que tuvo a carabalíes africanos y culíes asiáticos como principales protagonistas. A partir del registro documental de los principales gestores de la modernización minera y la base de datos del comercio transatlántico de esclavos, se relevará la importancia económica y cultural de la circulación de mano obra en Cuba.

Distribución de metales pesados en los sedimentos superficiales del Saco del Golfo de Cariaco, Sucre, Venezuela

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María Valentina Fuentes H

2010-10-01

Full Text Available El Golfo de Cariaco es un ecosistema marino con mucha productividad primaria, lo que le confiere especial importancia ecológica y socioeconómica. Sin embargo, los desechos de las actividades antropogénicas son descargados directamente o arrastradas por las escorrentías. El objetivo de este estudio fue determinar la distribución de cadmio, cobre, plomo, manganeso, níquel y zinc en las fracciones geoquímica de los sedimentos superficiales, usando el método modificado de extracción secuencial de la Comunidad Europea (BCR. Las concentraciones de los metales fueron medidas por espectroscopía de absorción atómica. Además, se compararon los contenidos de metales intercambiables y asociados a los carbonatos determinados por el procedimiento BCR modificado con los determinados por el método de Campanella. La recolección de muestras se hizo en 12 estaciones del sector oriental del Golfo de Cariaco, Estado Sucre, específicamente en el sector conocido como el Saco, en junio 2007. Las metodologías aplicadas fueron evaluadas usando un material de referencia certificado de sedimentos marino (HISS - 1. Los resultados indicaron que los métodos proveen exactitud y precisión adecuadas para la extracción de metales. Las concentraciones totales (μg g-1 fueron, Cd: < límite de detección (LD-5.0; Pb: 1.79- 60.41; Cu: no detectado (ND-42.18; Zn: 25.13-104.57; Mn: 66.31-80.29 y Ni: 3.29-24.58. Cd, Cu, Ni y Pb excedieron en varias estaciones los límites que pueden afectar la biota, establecidos por la Guía de Evaluación de la Calidad de los Sedimentos de Canadá. El cadmio fue el metal identificado como el más móvil, teniendo las más altas concentraciones como intercambiable y asociado a las fracciones de carbonatos. Sin embargo, Pb, Cu, Mn y Zn mostraron su mayor abundancia en la fracción asociada a materia orgánica y azufre. Los métodos no presentan diferencias significativas para extraer la primera fracción. Se encontraron

Symptomatic zinc deficiency in experimental zinc deprivation.

OpenAIRE

Taylor, C M; Goode, H F; Aggett, P J; Bremner, I; Walker, B E; Kelleher, J

1992-01-01

An evaluation of indices of poor zinc status was undertaken in five male subjects in whom dietary zinc intake was reduced from 85 mumol d-1 in an initial phase of the study to 14 mumol d-1. One of the subjects developed features consistent with zinc deficiency after receiving the low zinc diet for 12 days. These features included retroauricular acneform macullo-papular lesions on the face, neck, and shoulders and reductions in plasma zinc, red blood cell zinc, neutrophil zinc and plasma alkal...

Estudio comparativo entre fluorescencia de rayos X y reflectancia difusa de infrarrojos cercanos para la determinación de la retención en madera impregnada con arseniato de cobre cromatado

OpenAIRE

Baettig-Palma, Ricardo; Cornejo-Troncoso, Jorge; Salas-Maureira, Marina; Tapia-Sanhueza, Jaime

2014-01-01

Se realizó un análisis comparativo de la precisión de los resultados en la determinación de la retención de óxidos de cobre, cromo y arsénico en madera impregnada con arseniato de cobre cromatado entre fluorescencia de rayos X y espectrometría de reflectancia difusa de infrarrojos cercanos. Los resultados de la calidad de las predicciones fueron comparados entre sí y con valores de retención obtenidos experimentalmente por método gravimétrico, absorción atómica y por cenizas resultantes de su...

Estudio comparativo entre fluorescencia de rayos X y reflectancia difusa de infrarrojos cercanos para la determinación de la retención en madera impregnada con arseniato de cobre cromatado

OpenAIRE

Baettig-Palma,Ricardo; Cornejo-Troncoso,Jorge; Salas-Maureira,Marina; Tapia-Sanhueza,Jaime

2015-01-01

Se realizó un análisis comparativo de la precisión de los resultados en la determinación de la retención de óxidos de cobre, cromo y arsénico en madera impregnada con arseniato de cobre cromatado entre fluorescencia de rayos X y espectrometría de reflectancia difusa de infrarrojos cercanos. Los resultados de la calidad de las predicciones fueron comparados entre sí y con valores de retención obtenidos experimentalmente por método gravimétrico, absorción atómica y por cenizas resultantes de su...

Valoración del riesgo en salud en un grupo de población de Cali, Colombia, por exposición a plomo, cadmio, mercurio, ácido 2,4-diclorofenoxiacético y diuron, asociada al consumo de agua potable y alimentos

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Ghisliane Echeverry

2015-08-01

Conclusiones. Se cree que los hallazgos sobre contaminantes en estudios anteriores, pueden deberse a eventos puntuales de contaminación y se recomienda vigilar la bocatoma de agua y emitir alertas tempranas. El reporte sobre la presencia de cadmio en las muestras de pescado, sugiere que el control de la calidad de los alimentos por parte de las entidades reguladoras debe mejorar.

Efecto de la fertilización fosforada sobre el contenido de cadmio en cuatro suelos de Chile Effect of phosphate fertilizer on the soil cadmium content in four types of Chilean soils

OpenAIRE

Claudia Bonomelli; Carlos Bonilla; Adriana Valenzuela

2003-01-01

Los fertilizantes fosforados pueden contener cadmio (Cd) y al utilizarlos pueden entrar en las cadenas tróficas. El objetivo de este estudio fue evaluar el efecto de la fertilización fosforada sobre la concentración de Cd disponible en cuatro tipos de suelos de Chile, que pertenecían a los ordenes Inceptisol, Alfisol, Ultisol y Andisol. Los dos tratamientos usados fueron el testigo sin fertilización y la aplicación de una dosis de corrección con un fertilizante comercial, superfosfato triple ...

Evaluación de Riesgo Ecológico en la Aplicación de Lodos de Plantas de Tratamiento de Aguas Servidas a Suelos en la Región de la Araucanía

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Carolina Soto

2014-12-01

Full Text Available Los lodos generados en plantas de tratamiento de aguas servidas contienen materiales orgánicos ricos en nutrientes como nitrógeno (N, fósforo (P y potasio (K, además de metales y pequeñas cantidades de otros elementos tales como celulosa, ácidos orgánicos. Los lodos pueden ser considerados como residuos o reciclados mediante la incorporación a suelos. Frente a esta situación de disposición de lodos primarios en suelos, se determinó el efecto de dos muestras de lodos (una ya incorporada en suelo y otra fresca mediante la evaluación de bioensayos de toxicidad en Eisenia foetida durante 14 días, en donde se determinó que las muestras de lodos no presentaban toxicidad y que además existe una independencia entre la concentración y sus efectos en la mortalidad y crecimiento. Sumado a lo anterior, se evaluó las muestras de lodos en base a su contenidos de metales mediante el análisis de riesgo ecológico , en el cual obtenidos los antecedentes referidos a efectos y exposición, se integró la información para estimar el riesgo ecológico para metales pesados, en donde los factores de riesgo para el suelo son como cobre, cadmio, mercurio, níquel y zinc, la estimación del riesgo ecológico en el lodo incluye a todos los metales pesados y finalmente los factores de riesgo para el lodo aplicado en el suelo son todos los metales a excepción de arsénico.

Zinc

Science.gov (United States)

... Consumer Datos en español Health Professional Other Resources Zinc Fact Sheet for Consumers Have a question? Ask ... find out more about zinc? Disclaimer What is zinc and what does it do? Zinc is a ...

Avaliação e remoção de cobre em aguardentes de cana pela utilização dos aluminossilicatos: zeólita e bentonita Evaluation and removal of sugar cane brandy using aluminossilicates: zeolite and bentonite

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Fabiane de Oliveira Cantão

2010-10-01

Full Text Available A cachaça, bebida genuinamente nacional, é um produto de grande aceitação nos mercados interno e externo. Durante o processo de produção há alguns pontos críticos, ocorrendo a formação de contaminantes que podem afetar a qualidade da bebida, sendo necessário o conhecimento de sua composição química. Com este trabalho, objetivou-se comparar o comportamento do cobre, quando presente em solução alcoólica 40% e uma aguardente comercial (utilizando sulfato de cobre pentaidratado como fonte desse mesmo metal, além de avaliar a remoção de cobre na bebida, utilizando dois aluminossilicatos (zeólita e bentonita comumente empregados na adsorção de metais. A zeólita e bentonita adsorveram mais cobre quando estiveram presentes em solução alcoólica do que em aguardente. Esses resultados sugerem que o cobre em aguardente deva estar ligado a moléculas volumosas, dificultando sua entrada nos pequenos poros da argila bentonita e da zeólita ZSM-5. Quando os aluminossilicatos estiveram presentes na aguardente impregnada com cobre em alambique, a bentonita foi mais eficiente na remoção do cobre do que a zeólita; no entanto a zeólita é mais recomendada na remoção do cobre, pois a redução das concentrações dos componentes secundários foi menor, não descaracterizando a bebida.The "cachaça", a genuinely national drink, is a product of great acceptance in the domestic and international markets. Therefore, we need to know its chemical composition, as in the production process a few critical points due to the presence of contaminants that can affect the quality of the drink. This work is aimed to compare the behaviour of copper, when present in a 40% alcohol solution and a "cachaça" trade (using copper sulfate pentahydrate as a source of the same metal, in addition to evaluating the removal of copper in the spirit, using two aluminosilikate (zeolite and bentonite commonly employed in the adsorption of metals. The zeolite and

Estudio del mecanismo de la corrosión del recubrimiento de cobre químico usado en la protección de los espejos

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Bolaños-Rodríguez, E.

2002-04-01

Full Text Available Darkening of the silver layer in classical glass mirror manufacturing process can be caused by the copper layer corrosion, this may take place by the environment action or residual chemicals remaining on the "mirroring" step. The present work describes a possible mechanism of copper coating corrosion, studying the corrosion product compositions formed inside the "spot". It was found that defect on the silver layer are associated with chemicals and moisture, they produce the copper layer corrosion and the development of blisters in the silver coating.

El defecto conocido como "nube o mancha", que aparece en los espejos plateados fabricados usando las tecnologías convencionales, se atribuye a la corrosión del recubrimiento de cobre ocasionado por agentes agresivos que pueden atravesar las capas de pinturas, pero otra causa del problema puede estar originada por deficiencias durante las etapas del proceso de fabricación de los mismos. En este trabajo, se propone un mecanismo de la corrosión del recubrimiento de cobre a partir del estudio de la composición de los productos de la corrosión en la mancha. Los cloruros, los iones sodio y el oxígeno, procedentes de varias fuentes del sistema, reaccionan formando sales y óxidos de cobre que producen el ampollamiento de la película de plata, la ruptura de la misma y la presencia de estos productos de corrosión se refleja con la formación de manchas de diferentes tamaños, colores y formas sobre la superficie del espejo.

Informe final: desarrollo de la tecnología de inmovilización: estabilización / solidificación de desechos peligrosos en Costa Rica

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Luis Guillermo Romero Esquivel

2009-01-01

Full Text Available Se evaluó la tecnología de inmovilización en un lodo proveniente del tratamiento del agua residual del proceso de electrodeposición de cromo y níquel sobre cobre; dos reactivos químicos vencidos de metales tóxicos (plomo y cadmio; y dos residuos sólidos resultantes del tratamiento de desechos líquidos del Instituto Tecnológico de Costa Rica. Para la inmovilización de un lodo proveniente del tratamiento del agua residual del proceso de electrodeposición de cromo y níquel sobre cobre de la empresa Prolex S. A., se evaluó la eficacia de tres tipos de materiales cementantes: cemento Pórtland / carbonato de calcio (50/50 y 75/25; y cemento Pórtland/puzolana (85/15. Con el fin de determinar si el lodo se puede disponer en un relleno sanitario, se determinaron las características toxicas de lixiviación del lodo mediante el método Toxicity Characteristic Leaching Procedure (TCLP, determinándose que los niveles de lixiviación del níquel están por encima de la norma nacional. Se encontró que todos los cementos logran la inmovilización satisfactoria del níquel, pero la mezcla cemento Pórtland/puzolana (85/15 presenta las mejores resistencias mecánicas para la disposición del material tratado en un relleno sanitario; por lo tanto es la más recomendable para el tratamiento. Este tipo de material cementante también se evaluó a nivel piloto, utilizando una mezcladora del tipo empleado en construcción. La resistencia mecánica del material así preparado está cuatro veces por encima de la formulación que utilizaba la empresa Prolex S. A., que incluye un aditivo importado, cemento convencional y piedra. La tecnología de inmovilización también resultó satisfactoria en el tratamiento de reactivos vencidos de metales tóxicos (plomo y cadmio. En este caso, los cementos convencional, Pórtland y Pórtland con puzolanas fueron eficaces al inmovilizar acetato de cadmio en un 11%�

Concentrações de ferro, cobre, zinco e manganês em equinos da raça Puro-sangue Lusitano, antes e após exercício

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Rodrigo A.B. Minini

2013-08-01

Full Text Available O presente trabalho objetivou determinar a atividade sérica dos microminerais ferro, cobre, zinco e manganês em 30 equinos atletas da raça Puro-sangue Lusitano (PSL, antes e depois de exercícios, atestados por avaliações clínicas e laboratoriais. Amostras de sangue foram colhidas, antes e imediatamente após 20 minutos de exercício físico de trote e galope suaves realizados em pista de areia, para a realização das dosagens dos microminerais. A concentração dos microelementos foi determinada por espectrofotometria de absorção atômica. Observou-se que após o exercício, a atividade sérica de ferro não sofreu variações (P=0,2365, enquanto os valores de cobre se elevaram significativamente após o treinamento (P<0,001. Já o zinco e o manganês diminuíram após o exercício (P<0,001. Pode-se concluir que o exercício físico de curta duração pode gerar sudorese capaz de alterar as concentrações séricas de ferro, cobre, zinco e manganês em cavalos atletas da raça Puro-sangue Lusitano.

Cadmio en sangre y su relación con el consumo de tabaco en una población laboral hospitalaria Blood cadmium and its relationship with smoking in a hospital employee population Cádmio presente no sangue e a sua relação com o consumo de tabaco numa população de trabalhadores de um hospital

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Cristina Fernández Pérez

2012-12-01

Full Text Available La exposición de la población general al cadmio es un problema de salud pública, siendo las principales fuentes tanto el consumo de tabaco como la exposición al humo del mismo.El objetivo de este trabajo fue determinar la concentración de cadmio en sangre en una población laboral hospitalaria y su asociación con el consumo de tabaco.Se administró el cuestionario PESA® a 395 sujetos. El cadmio en sangre se midió por espectrometría de absorción atómica con atomización electrotérmica.La mediana de cadmio en sangre fue 0,29 μg/L. La mediana de cadmio de los fumadores (0,83 μg/L fue la más elevada y la de los exfumadores (0,31 μg/L fue a su vez más elevada que la de aquellos que nunca habían fumado (0,21 μg/L. Dentro del grupo de fumadores, se observó una asociación entre la concentración de cadmio y el número de cigarrillos inhalados.En el grupo de exfumadores se observó una asociación con el número de cigarrillos que habían consumido y una correlación negativa entre el tiempo transcurrido desde el abandono del hábito tabáquico y la concentración de cadmio en sangre.Dentro del grupo de los que nunca habían fumado, se observó una diferencia entre la concentración de cadmio de los fumadores pasivos (0,24 μg/L y los que no lo eran (0,20 μg/L.La concentración de cadmio en sangre se relacionó con el consumo de tabaco. Son necesarios más estudios para confirmar el hallazgo de concentraciones de cadmio más elevadas en los fumadores pasivos.Exposure to cadmium is a public health problem due to the broad exposure to this toxic substance among the general population. The main sources of exposure are both tobacco consumption and tobacco smoke.The aim of this study was to determine the blood cadmium concentration in an employee population drawn from our hospital and its association with tobacco consumption.The exposure questionnaire PESA® was administered to 395 employees. Blood cadmium was measured by electrothermal

EFECTO DE LA ALTURA DEL MANGUITO EN UNIONES SOLDADAS EN CAÑERÍAS DE COBRE BUSHING HEIGHT EFFECT IN SOLDERED COPPER PIPE JOINTS

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Víctor Carmona

2006-12-01

Full Text Available Se perforó un tubo de cobre de 28,6 mm de diámetro, por el proceso de taladrado por fluencia térmica (TFT. Se prepararon manguitos de diferentes alturas, haciendo un preperforado con brocas convencionales HSS de diferentes diámetros. Se seleccionaron manguitos de dos alturas diferentes. Se determinó la circularidad de la perforación. Se soldó un tubo cobre de ø 12,7 mm en forma perpendicular a un tubo de cobre de ø 28,6 mm y se determinó la resistencia a la tracción de la unión soldada, para lo cual se diseñó un dispositivo mecánico que fue adaptado en la máquina universal de ensayos. Se hicieron ensayos de microdureza y metalografía de la unión. Se concluyó que el manguito de menor altura es suficiente para que la unión alcance la máxima resistencia.Copper tubes were drilled with thermal flow drilling. Conventional HSS drills diameters were used to make pre drilling holes. Different height bushings were made. Two of the bushing heights were selected. The bushing circularity was measured. A ø 12,7 mm tube was welded perpendicularly on a ø 28,6 mm tube. A especial support device was designed and it was adapted to the Universal Test Machine, to determine the tensile stress of the brazing joint. The micro hardness and metallographic test were made in the brazing zone. As a conclusion the lower height bushing is enough to reach the maximum resistance.

Zinco, estresse oxidativo e atividade física Zinc, oxidative stress and physical activity

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Josely Correa Koury

2003-12-01

Full Text Available A atividade física intensa aumenta a formação de espécies reativas de oxigênio que podem causar lesões musculares e danos na membrana de eritrócitos, prejudicando o desempenho de atletas. Para prevenir os efeitos causados pelo estresse oxidativo, o organismo possui vários mecanismos antioxidantes, alguns dependentes de zinco. As propriedades antioxidantes desse mineral são explicadas pelo seu papel na regulação da síntese da metalotioneína, na estrutura da enzima superóxido dismutase e na proteção de agrupamentos sulfidrila de proteínas de membranas celulares por antagonismo com metais pró-oxidantes como ferro e cobre. Estudos têm demonstrado que a fragilidade osmótica de eritrócitos está relacionada à função do zinco na membrana celular. Atletas geralmente apresentam ingestão dietética desse mineral insuficiente para compensar as perdas aumentadas pelo suor e urina e para atender a demanda bioquímica. Este trabalho de revisão visa mostrar a importância biológica e nutricional do zinco na proteção antioxidante durante a atividade física intensa.During intense physical activity there is an increased production of reactive oxygen species that can cause muscle injury and damage to erythrocyte cell membranes, thus impairing athletic performance. In order to prevent the effects caused by oxidative stress, the organism has several antioxidant mechanisms, some of which depending on zinc. The antioxidant properties of this mineral are explained by its role in the regulation of metallothionein synthesis, in the structure of superoxide dismutase, and in the protection of sulfhydryl groups of cell membrane proteins through antagonism with pro-oxidant metals such as iron and copper. Recent studies have shown that the osmotic fragility of erythrocytes is related to the zinc function in cell membranes. Athletes generally have dietary zinc intakes inadequate to compensate for the increased sweat and urine losses to meet and

Recubrimiento de cobre sobre Al₂O₃ mediante reducción autocatalítica

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Gómez de Salazar, J. M.

1998-05-01

Full Text Available A method for obtaining copper coatings on ceramic tenacious substrates as the alumina is described. Its principal applications are found in the electronic industry; they can also be employed as interlayer on metal-ceramic disimilar bondings produced by solid state welding or brazing. Optimal activation conditions were determined as well as the influence of the substrate surface preparation and the deposition rate on the adhesion. The kinetics study of the process was carried out by gravimetric and electrochemical methods.

Se describe un método para la obtención de recubrimientos de cobre sobre un cerámico tenaz, como es la alúmina. Entre sus principales aplicaciones se encuentra la industria electrónica, aunque también pueden emplearse como intermediarios en las uniones disimilares metal-cerámico realizadas mediante soldadura en estado sólido o soldadura fuerte. Se determinan las condiciones óptimas de activación y la influencia de la preparación superficial del substrato, así como de la velocidad de deposición sobre la adherencia de la capa de cobre. El estudio cinético del proceso se realizó mediante ensayos electroquímicos.

Evaluación multicriterio del proyecto minero "Cobre las Cruces", Gerena (Sevilla) : análisis de riesgos para los recursos hídricos

OpenAIRE

Beltrán Muñoz, María Jesús

2008-01-01

El objetivo de este trabajo es el análisis de las posibles implicaciones sobre los recursos hídricos de una explotación minera. Concretamente, se analizarán estas implicaciones en el estudio de caso del proyecto minero Cobre Las Cruces, propiedad de la empresa canadiense Inmet Mining Corporation.

Dietary phytate, zinc and hidden zinc deficiency.

Science.gov (United States)

Sandstead, Harold H; Freeland-Graves, Jeanne H

2014-10-01

Epidemiological data suggest at least one in five humans are at risk of zinc deficiency. This is in large part because the phytate in cereals and legumes has not been removed during food preparation. Phytate, a potent indigestible ligand for zinc prevents it's absorption. Without knowledge of the frequency of consumption of foods rich in phytate, and foods rich in bioavailable zinc, the recognition of zinc deficiency early in the illness may be difficult. Plasma zinc is insensitive to early zinc deficiency. Serum ferritin concentration≤20μg/L is a potential indirect biomarker. Early effects of zinc deficiency are chemical, functional and may be "hidden". The clinical problem is illustrated by 2 studies that involved US Mexican-American children, and US premenopausal women. The children were consuming home diets that included traditional foods high in phytate. The premenopausal women were not eating red meat on a regular basis, and their consumption of phytate was mainly from bran breakfast cereals. In both studies the presence of zinc deficiency was proven by functional responses to controlled zinc treatment. In the children lean-mass, reasoning, and immunity were significantly affected. In the women memory, reasoning, and eye-hand coordination were significantly affected. A screening self-administered food frequency questionnaire for office might help caregiver's identify patients at risk of zinc deficiency. Copyright © 2014 Elsevier GmbH. All rights reserved.

Age and geochemistry of host rocks of the Cobre Panama porphyry Cu-Au deposit, central Panama: Implications for the Paleogene evolution of the Panamanian magmatic arc

Science.gov (United States)

Baker, Michael J.; Hollings, Peter; Thompson, Jennifer A.; Thompson, Jay M.; Burge, Colin

2016-04-01

The Cobre Panama porphyry Cu-Au deposit, located in the Petaquilla district of central Panama, is hosted by a sequence of medium- to high-K calc-alkaline volcanic and sub-volcanic rocks. New crystallisation ages obtained from a granodiorite Petaquilla batholith and associated mineralised diorite to granodiorite porphyry stocks and dikes at Cobre Panama indicate that the batholith was emplaced as a multi-phase intrusion, over a period of 4 million years from 32.20 ± 0.76 Ma to 28.26 ± 0.61 Ma, while the porphyritic rocks were emplaced over a 2 million year period from 28.96 ± 0.62 Ma to 27.48 ± 0.68 Ma. Both the volcanic to sub-volcanic host rocks and intrusive rocks of the Cobre Panama deposit evolved via fractional crystallisation processes, as demonstrated by the major elements (e.g. Al2O3, Fe2O3, TiO2 and MgO) displaying negative trends with increasing SiO2. The Petaquilla intrusive rocks, including the diorite-granodiorite porphyries and granodiorite batholith, are geochemically evolved and appear to have formed from more hydrous magmas than the preceding host volcanic rocks, as evidenced by the presence of hornblende phenocrysts, higher degrees of large-ion lithophile element (LILE) and light rare earth element (LREE) enrichment and heavy rare earth element (HREE) depletion, and higher Sr/Y and La/Yb values. However, the degree of LREE enrichment, HREE depletion and La/Yb values are insufficient for the intrusive rocks to be considered as adakites. Collectively, the volcanic and intrusive rocks have LILE, REE and mobile trace element concentrations similar to enriched Miocene-age Cordilleran arc magmatism found throughout central and western Panama. Both the Petaquilla and Cordilleran arc magmatic suites are geochemically more evolved than the late Cretaceous to Eocene Chagres-Bayano arc magmas from northeastern Panama, as they display higher degrees of LILE and LREE enrichment. The geochemical similarities between the Petaquilla and Cordilleran arc magmas

Extracción de cobre desde soluciones clorhídricas con LIX 860N-IC y LIX 84-IC

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Navarro, Carlos María

2001-08-01

Full Text Available In this work, the extraction of copper from chloride solutions with two hydroxyoximes: 5- nonylsalicylaldoxime (LIX 860N-IC and 2-hydroxy-5-nonylacetophenona oxime (LIX 84-IC is discussed. The results showed that an increase in the acidity and an increase in the total concentration of chloride ions in the aqueous phase decreased significantly the extraction of copper as well as the extraction of iron for both extractants. This effect of the chloride ions can be explained by the formation of a series of chloro complexes of Cu(II and Fe(III in the aqueous phase. The effect of initial pH and total chloride concentration on the extraction of chloride by the organic phase suggests that LIX 860N-IC, and to a lesser extent LIX 84-IC, extract small amounts of the cationic complex, CuCl⁺. An increase in the concentration of chloride ions also produced a small decrease in the rate of copper extraction with both hydroxyoximes.

En este trabajo se discute el estudio de la extracción de cobre desde soluciones clorhídricas con dos hidroxioximas: 5-nonilsalicilaldoxima (LIX 860N-IC, y 2-hidroxi-5 nonilacetofenona oxima (LIX 84-IC. Los resultados indicaron que al aumentar la acidez o aumentar la concentración de cloruro en la fase acuosa se produce una significativa disminución en la extracción de cobre y hierro con ambas hidroxioximas. Este efecto del ion cloruro se explica por la formación de varios clorocomplejos de Cu(II y Fe(III en la solución acuosa. El efecto del pH y la concentración total de cloruro en la extracción de cloruro sugiere que el LIX 860N-IC, y en menor grado el LIX 84-IC extraen pequeñas cantidades del catión monovalente, CuCl⁺. Se determinó también que un aumento en la concentración de cloruro en la solución acuosa produce una leve disminución en la velocidad de extracción del cobre con ambas hidroxioximas.

Separation of Impurities in the Zinc Rectification Process by Radioactive Isotopes; Separation des Impuretes, a l'Aide de Radioisotopes, dans l'Affinage du Zinc par Voie Seche; ОТДЕЛЕНИЕ ПРИМЕСЕЙ В ПРОЦЕССЕ РЕКТИФИКАЦИИ ЦИНКА С ПРИМЕНЕНИЕМ РАДИОАКТИВНЫХ РАДИОИЗОТОПОВ; Estudio Mediante Radioisotopos de la Separacion de Impurezas en el Proceso de Purificacion del Cinc

Energy Technology Data Exchange (ETDEWEB)

Akerman, K.; Brafman, M.; Fik, H.; Kitala, J.; Nowak, M.; Poczynajlo, A. [Institute of Nuclear Research, Polish Academy of Sciences, Warsaw (Poland)

1963-03-15

experiences confirment la theorie elaboree par A. Krupkowski. Elles permettent en outre de formuler des propositions concretes concernant une modification a apporter aux parametres qui traduisent les conditions dans lesquelles s'effectue la condensation des vapeurs zinc-cadmium dans la colonne cadmium. Grace a cette modification, on peut augmenter la recuperation de cadmium provenant du metal primitif, et ameliorer la qualite du zinc de grande purete obtenue par redistillation. (author) [Spanish] En la memoria la separacion de impurezas en el proceso de purificacion del cinc se estudia con ayuda de radioisotopos. Se describen brevemente el proceso de redestilacion del cinc en columnas del tipo New Jersey y sus principios teoricos, establecidos por A. Krupkowski. Se resumen las conclusiones practicas que se desprenden de la expresion matematica del proceso, obtenida basandose en la teoria mencio nada. Se describen asimismo los experimentos de separacion de impurezas de alto y bajo punto de ebullicion presentes en el cinc y el comportamiento del propio componente basico en condiciones normales de trabajo. Estos experimentos se llevaron a cabo utilizando los radioisotopos {sup 64}Cu y {sup 59}Fe (impureza de alto punto de ebullicion), used (impureza de bajo punto de ebullicion) y {sup 69m}Zn (componente basico). Las conclusiones extraidas de los datos experimentales corroboran la teoria de la redestilacion del cinc, elaborada por A. KrupkowskL Ademas, estas conclusiones permiten definir las propuestas que cabe formular con respecto a cambios en los parametros con arreglo a los cuales la condensacion de los vapores de cinc-cadmio se efectua en la columna del cadmio. Estos cambios permiten aumentar la recuperacion de cadmio del metal cargado y mejorar la calidad del cinc de alta pureza, obtenido por redestilacion. (author) [Russian] V rabote korotko opisan process rektifikacii cinka v kolonnah tipa N'ju-Dzhersi i teoreticheskie osnovy jetogo processa, razrabotannye A. Krupkovskim

Crescimento e qualidade de mudas de Timbó e Dedaleiro cultivadas em solo contaminado por cobre Growth and quality of Ateleia glazioviana and Lafoensia pacari seedlings cultivated in copper contaminated soil

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Rodrigo F. da Silva

2012-08-01

Full Text Available As atividades de mineração e de viticultura do Rio Grande do Sul têm contribuído para a contaminação do solo por cobre. Este trabalho objetivou avaliar o efeito de doses de cobre no crescimento e na qualidade de mudas de timbó (Ateleia glazioviana e dedaleiro (Lafoensia pacari. O delineamento foi inteiramente casualizado em arranjo fatorial (2 x 4, formado de duas espécies florestais e quatro doses de cobre (0, 64, 128 e 192 mg kg-1 de solo com cinco repetições. Avaliaram-se altura da planta, diâmetro do colo, peso da matéria seca radicular e da parte aérea, comprimento e área superficial específica radicular e os seguintes índices de qualidade de mudas: relação entre altura da parte aérea e diâmetro do coleto; altura da parte aérea e peso da matéria seca da parte aérea e o índice de qualidade de Dickson, em que os resultados revelaram que as doses de cobre testada reduziram a qualidade de mudas do timbó enquanto o dedaleiro apresentou melhor qualidade com 128 mg kg-1 de Cu. O cobre influenciou os parâmetros de crescimento das mudas de timbó porém aumentou significativamente o comprimento e a área superficial específica do dedaleiro até 128 mg kg-1 de Cu. Mudas de dedaleiro são mais tolerantes à contaminação do solo que as de timbó e apresentam melhor qualidade em doses mais elevadas de cobre.The mining and viticulture activities in the State of Rio Grande do Sul, Brazil have contributed to soil contamination by copper. The aim of this study was to evaluate the effect of copper doses on growth and quality of Ateleia glazioviana and Lafoensia pacari seedlings. The experimental design was completely randomized in a factorial scheme (2 x 4 with five replications. The experiment involved two forest species and three copper doses (64, 128 and 192 mg kg-1. The plant height, stem diameter, root and shoot dry-mass, length and specific superficial area of roots, as well as seedlings quality index: relationship between

[Improvement in zinc nutrition due to zinc transporter-targeting strategy].

Science.gov (United States)

Kambe, Taiho

2016-07-01

Adequate intake of zinc from the daily diet is indispensable to maintain health. However, the dietary zinc content often fails to fulfill the recommended daily intake, leading to zinc deficiency and also increases the risk of developing chronic diseases, particularly in elderly individuals. Therefore, increased attention is required to overcome zinc deficiency and it is important to improve zinc nutrition in daily life. In the small intestine, the zinc transporter, ZIP4, functions as a component that is essential for zinc absorption. In this manuscript, we present a brief overview regarding zinc deficiency. Moreover, we review a novel strategy, called "ZIP4-targeting", which has the potential to enable efficient zinc absorption from the diet. ZIP4-targeting strategy is possibly a major step in preventing zinc deficiency and improving human health.

Zinc content of selected tissues and taste perception in rats fed zinc deficient and zinc adequate rations

International Nuclear Information System (INIS)

Boeckner, L.S.; Kies, C.

1986-01-01

The objective of the study was to determine the effects of feeding zinc sufficient and zinc deficient rations on taste sensitivity and zinc contents of selected organs in rats. The 36 Sprague-Dawley male weanling rats were divided into 2 groups and fed zinc deficient or zinc adequate rations. The animals were subjected to 4 trial periods in which a choice of deionized distilled water or a solution of quinine sulfate at 1.28 x 10 -6 was given. A randomized schedule for rat sacrifice was used. No differences were found between zinc deficient and zinc adequate rats in taste preference aversion scores for quinine sulfate in the first three trial periods; however, in the last trial period rats in the zinc sufficient group drank somewhat less water containing quinine sulfate as a percentage of total water consumption than did rats fed the zinc deficient ration. Significantly higher zinc contents of kidney, brain and parotid salivary glands were seen in zinc adequate rats compared to zinc deficient rats at the end of the study. However, liver and tongue zinc levels were lower for both groups at the close of the study than were those of rats sacrificed at the beginning of the study

Determinación enzimática y metales pesados en cerebro e hígado del modelo ecotoxicológico Gambusia punctata (Poeciliidae Enzymatic determination and heavy metals in the brain and liver in ecotoxicological model Gambusia punctata (Poeciliidae

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George Argota Pérez

2013-02-01

Full Text Available Se realizó un estudio durante el 2011, con vistas a evaluar los niveles de actividad enzimática y metales pesados bioacumulados en cerebro e hígado de la especie Gambusia punctata, que habita en los ecosistemas San Juan y Filé de Santiago de Cuba, para lo cual se seleccionaron 3 estaciones, correspondientes a la parte alta, media y baja de ambos sistemas. Se escogieron ejemplares que midieron biométricamente de 2,1-3,0 cm de longitud total. Se determinó la enzima acetilcolinesterasa en el cerebro y la glutation-S-transferasa y catalasa, respectivamente, en el hígado. En ambos órganos se analizaron concentraciones de cobre, cinc, plomo y cadmio, tratados por vía húmeda y cuantificados por espectroscopia de plasma inductivamente acoplado con vista axial. En la especie del San Juan, los niveles enzimáticos variaron entre las estaciones, siendo mayores y estadísticamente diferentes para las hembras (pA study during 2011 was carried out in order to evaluate the levels of enzymatic activity and heavy metals bioaccumulated in brain and liver of the species Gambusia punctata, inhabiting San Juan and Filé ecosystems in Santiago de Cuba. For this purpose 3 stations were selected, corresponding to the upper, middle and lower parts of both systems. Specimens biometrically measuring 2.1-3.0 cm in total length were chosen. Acetylcholinesterase enzyme in the brain and glutathione-S-transferase and catalase in the liver were determined, respectively. Copper, zinc, lead and cadmium concentrations were analyzed in both organs, wet processed and quantified by axial view inductively coupled plasma spectroscopy. In San Juan species the enzymatic levels varied between the stations, being higher and statistically different for females (p<0.05, but in that from Filé they were similar between the parts and genders. Regarding metals, concentrations were not detected in brain, neither lead nor cadmium in the liver. Copper and zinc concentrations were higher

Níveis de cobre em amostras de cachaça produzidas na região noroeste do Rio Grande do Sul, Brasil

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Garbin Renata

2005-01-01

Full Text Available Com o objetivo de conhecer a qualidade, com destaque para os níveis de cobre, foram analisadas 25 amostras de cachaça artesanal, produzidas e comercializadas em 17 municípios pertencentes às microrregiões Ijuí, Cruz Alta, Santa Rosa e Três Passos, que integram o noroeste do Rio Grande do Sul, Brasil e, compararam-se os valores encontrados, com aqueles estabelecidos pela Legislação. Para as análises, procedeu-se a avaliação dos aspectos gerais das amostras através de observações visuais e olfativas, conforme as recomendações do Ministério da Agricultura para análise de bebidas alcoólicas destiladas. O teor alcoólico foi determinado utilizando-se método densimétrico e os teores de cobre foram determinados através de espectrofotometria de absorção atômica (EAA. Aplicou-se os testes de ANOVA e Tukey. Foram constatados, a partir da análise dos aspectos gerais, que 72% das amostras apresentaram anormalidades de limpidez. Verificou-se que a Microrregião Três Passos apresentou 42,86% de suas amostras fora dos limites estabelecidos pela legislação para o teor alcoólico, entretanto os valores médios deste mesmo parâmetro, para todas as amostras das quatro microrregiões, situaram-se dentro do que estabelece a legislação. Quanto aos níveis de cobre, a maior concentração média foi observada na Microrregião Três Passos (10,22mg L-1 enquanto que na Microrregião Cruz Alta foram observados os menores níveis médios deste metal (2,95mg L-1. Apenas as microrregiões Ijuí e Três Passos apresentaram diferenças estatisticamente significativas (P<0,05 quanto aos níveis médios de cobre quando comparadas as outras microrregiões. A média regional para os níveis deste metal nas quatro microrregiões foi de 5,71mg L-1, valor acima do limite máximo de 5mg L-1 permitido pela legislação. Os resultados do presente estudo, apesar de avaliarem apenas alguns dos parâmetros de qualidade para bebidas alcoólicas destiladas

TOLERANCE OF AGAVE TEQUILANA TO HIGH LEVELS OF DIVALENT METAL CATIONS

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Elmi Roseida Cen-Cen

2015-11-01

Full Text Available Los agaves son plantas que pertenecen a un género constituido por numerosas especies, adaptadas para crecer en muy diversos hábitats, algunos con condiciones ambientales extremas. Distintas especies de agave crecen sobre distintos tipos de suelos, algunas en suelos con muy bajo contenido de nutrientes minerales y otras en suelos salinos o en suelos contaminados con iones metálicos. La relación planta-suelo ha sido escasamente estudiada en este género por lo que se desconoce, entre otras cuestiones, cuál es la capacidad de los agaves para absorber, transportar y almacenar nutrientes minerales, cuáles son los mecanismos celulares y bioquímicos que utilizan, o si poseen especial sensibilidad o tolerancia a los iones metálicos. Este estudio reporta el efecto de diversas concentraciones de sulfato de cadmio, cobalto, cobre, zinc o de manganeso sobre plántulas deAgave tequilana, bajo condiciones controladas de laboratorio; la concentración mínima de esos iones metálicos requerida para inducir un efecto tóxico visualmente detectable en tiempos cortos (ocho días; describimos los efectos tóxicos que estos metales generan sobre las plántulas de agave; y reportamos la cantidad de Cu2+, Cd2+ y Co2+ que se acumula en las hojas de plántulas de agave tratadas con altas concentraciones (milimolares de esos metales. Nuestros resultados muestran que, en experimentos de toxicidad aguda y bajo las condiciones aquí establecidas, elA. tequilanaposee una notable tolerancia a altas concentraciones de los distintos metales iónicos probados, incluyendo tanto micronutrientes como metales tóxicos, así como la capacidad de transportar en altas cantidades estos metales a tejido aéreo.

Desarrollo y caracterización del material compuesto de base cobre reforzado con cerámicas intermetálicas de TiB₂

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López, M.

2005-08-01

Full Text Available In this work, mechanical and electrical properties of copper base composites alloy sstrengthened by dispersed TiB₂ particles are characterized. Powders of copper and TiB₂ were mechanically ball milled in a planetary mill during 12 and 36 h under a protective atmosphere of argon. Resulting powders were compacted uniaxially at 923 K under 90 MPaduring 2 h. Part of these compacts were hot rolled at temperatures ranging between 1073 and 1023 K with 20 % reduction. Comparing the properties of materials after this thermomechanical process with that of as-consolidated, it was observed an electrical conductivity increase, and a decrease on hardness and ductility.

En este trabajo se han caracterizado las propiedades mecánicas y eléctricas de materiales compuestos de base cobre reforzados mediante la dispersión de partículas de TiB₂. Las mezclas cobre-cerámica, se obtuvieron por molienda mecánica de polvos de cobre y TiB₂, en un molino planetario, durante 12 y 36 h bajo atmósfera de argón. El polvo resultante se compactó bajo una presión uniaxial 90 MPa durante 2 h a 923 K. Algunos de los compactos resultantes se laminaron a una temperatura comprendida entre 1073 y 1023 K hasta alcanzarse una reducción del 20 %. Comparando las propiedades de los materiales, tras este procesado termomecánico, con las propiedades de los materiales compactados uniaxialmente, se encontró que la laminación en caliente aumenta la conductividad eléctrica, pero da lugar a una disminución del valor de la dureza y la ductilidad.

Does the oral zinc tolerance test measure zinc absorption

Energy Technology Data Exchange (ETDEWEB)

Valberg, L.S.; Flanagan, P.R.; Brennan, J.; Chamberlain, M.J.

1985-01-01

Increases in plasma zinc concentration were compared with radiozinc absorption after oral test doses. Ten healthy, fasting subjects were each given 385 mumol zinc chloride (25 mg Zn) labelled with 0.5 muCi /sup 65/ZnCl/sub 2/ and a non-absorbed marker, /sup 51/CrCl/sub 3/, dissolved in 100 ml of water; another 10 persons were given 354 mumol zinc chloride and 125 g of minced turkey containing 31 mumol zinc also labelled with /sup 65/Zn and /sup 51/Cr. Measurements were made of plasma zinc concentration at hourly intervals for 5 hours, radiozinc absorption by stool counting of unabsorbed radioactivity 12-36 hours later, and radiozinc retention by whole body counting at 7 days. The mean percentage of radiozinc absorbed and retained in the body from the two test meals was found to be identical (42%). In contrast the increased area under the plasma zinc curve up to 5 hours after the turkey meal, 28 +/- 9 mumol/L (mean +/- SD) was significantly less than that for zinc chloride alone, 47 +/- 15 mumol/L, p less than 0.005. Despite this difference, a good correlation was found between the area under the plasma zinc curve and /sup 65/Zn absorption in individual subjects after each meal. The discrepancy between the results of zinc absorption derived from the plasma zinc curve and /sup 65/Zn absorption for the liquid and solid test meals was most likely explained by binding of zinc to food and delayed gastric emptying of the solid meal. With a test meal of turkey meat at least this dampened the plasma appearance of zinc but did not affect its overall absorption.

Does the oral zinc tolerance test measure zinc absorption

International Nuclear Information System (INIS)

Valberg, L.S.; Flanagan, P.R.; Brennan, J.; Chamberlain, M.J.

1985-01-01

Increases in plasma zinc concentration were compared with radiozinc absorption after oral test doses. Ten healthy, fasting subjects were each given 385 mumol zinc chloride (25 mg Zn) labelled with 0.5 muCi 65 ZnCl 2 and a non-absorbed marker, 51 CrCl 3 , dissolved in 100 ml of water; another 10 persons were given 354 mumol zinc chloride and 125 g of minced turkey containing 31 mumol zinc also labelled with 65 Zn and 51 Cr. Measurements were made of plasma zinc concentration at hourly intervals for 5 hours, radiozinc absorption by stool counting of unabsorbed radioactivity 12-36 hours later, and radiozinc retention by whole body counting at 7 days. The mean percentage of radiozinc absorbed and retained in the body from the two test meals was found to be identical (42%). In contrast the increased area under the plasma zinc curve up to 5 hours after the turkey meal, 28 +/- 9 mumol/L (mean +/- SD) was significantly less than that for zinc chloride alone, 47 +/- 15 mumol/L, p less than 0.005. Despite this difference, a good correlation was found between the area under the plasma zinc curve and 65 Zn absorption in individual subjects after each meal. The discrepancy between the results of zinc absorption derived from the plasma zinc curve and 65 Zn absorption for the liquid and solid test meals was most likely explained by binding of zinc to food and delayed gastric emptying of the solid meal. With a test meal of turkey meat at least this dampened the plasma appearance of zinc but did not affect its overall absorption

Influence of DNA-methylation on zinc homeostasis in myeloid cells: Regulation of zinc transporters and zinc binding proteins.

Science.gov (United States)

Kessels, Jana Elena; Wessels, Inga; Haase, Hajo; Rink, Lothar; Uciechowski, Peter

2016-09-01

The distribution of intracellular zinc, predominantly regulated through zinc transporters and zinc binding proteins, is required to support an efficient immune response. Epigenetic mechanisms such as DNA methylation are involved in the expression of these genes. In demethylation experiments using 5-Aza-2'-deoxycytidine (AZA) increased intracellular (after 24 and 48h) and total cellular zinc levels (after 48h) were observed in the myeloid cell line HL-60. To uncover the mechanisms that cause the disturbed zinc homeostasis after DNA demethylation, the expression of human zinc transporters and zinc binding proteins were investigated. Real time PCR analyses of 14 ZIP (solute-linked carrier (SLC) SLC39A; Zrt/IRT-like protein), and 9 ZnT (SLC30A) zinc transporters revealed significantly enhanced mRNA expression of the zinc importer ZIP1 after AZA treatment. Because ZIP1 protein was also enhanced after AZA treatment, ZIP1 up-regulation might be the mediator of enhanced intracellular zinc levels. The mRNA expression of ZIP14 was decreased, whereas zinc exporter ZnT3 mRNA was also significantly increased; which might be a cellular reaction to compensate elevated zinc levels. An enhanced but not significant chromatin accessibility of ZIP1 promoter region I was detected by chromatin accessibility by real-time PCR (CHART) assays after demethylation. Additionally, DNA demethylation resulted in increased mRNA accumulation of zinc binding proteins metallothionein (MT) and S100A8/S100A9 after 48h. MT mRNA was significantly enhanced after 24h of AZA treatment also suggesting a reaction of the cell to restore zinc homeostasis. These data indicate that DNA methylation is an important epigenetic mechanism affecting zinc binding proteins and transporters, and, therefore, regulating zinc homeostasis in myeloid cells. Copyright © 2016 Elsevier GmbH. All rights reserved.

Method of capturing or trapping zinc using zinc getter materials

Science.gov (United States)

Hunyadi Murph, Simona E.; Korinko, Paul S.

2017-07-11

A method of trapping or capturing zinc is disclosed. In particular, the method comprises a step of contacting a zinc vapor with a zinc getter material. The zinc getter material comprises nanoparticles and a metal substrate.

Análise proteômica em células leveduriformes do fungo Paracoccidioides sp. em excesso de cobre

OpenAIRE

Portis, Igor Godinho

2015-01-01

Paracoccidioidomicose é a micose sistêmica mais prevalente da América Latina, causada por fungos do gênero Paracoccidioides spp. O fungo cresce como micélio no ambiente saprofítico, sendo a infecção causada por propágulos de micélio e ou conídios, que se diferenciam na forma leveduriforme no hospedeiro. O cobre é um micronutriente essencial para eucariotos e bactérias, de extrema importância a várias proteínas, sendo cofator de muitas enzimas e utilizado em diversos proces...

Magnetic properties of CoBr2.6[(1-x)H2O.xD2O

International Nuclear Information System (INIS)

Hijmans, J.P.A.M.

1979-01-01

The magnetic properties of CoBr 2 .6H 2 O and the anomalous effects upon deuteration have been studied. The experimental techniques employed are described and the high-temperature behaviour of the susceptibility analysed in terms of a crystal-field model combined with a high-temperature expansion for the exchange contribution. The high-temperature behaviour of the specific heat is studied and several kinds of experiments performed in the ordered state below Tsub(N). The XY plane anisotropy is deduced from antiferromagnetic resonance data and attention paid to the spatial dimensionality of the system. A comparison of parameters determined from experiments below and above Tsub(N) is made and the effects of deuteration discussed. (Auth.)

The bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens

OpenAIRE

Veldkamp, T.; Diepen, van, J.T.M.; Bikker, P.

2014-01-01

Zinc is an essential trace element for all farm animal species. It is commonly included in animal diets as zinc oxide, zinc sulphate or organically bound zinc. Umicore Zinc Chemicals developed zinc oxide products with different mean particle sizes. Umicore Zinc Chemicals requested Wageningen UR Livestock Research to determine the bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens. A precise estimate of the bioavailability of zinc sources is required both for fulf...

PROPIEDADES QUÍMICAS DE UN LUVISOL DESPUÉS DE LA CONVERSIÓN DEL BOSQUE A LA AGRICULTURA EN CAMPECHE, MÉXICO

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Juan Medina-M\\u00E9ndez

2009-01-01

Full Text Available El objetivo de este trabajo fue evaluar los cambios en las propiedades químicas de un suelo Luvisol en Campeche, México en un período de 30 años (1974 al 2003. Los principales cultivos en el área de estudio fueron el maíz bajo temporal y mango bajo riego. Con fines de comparación también se consideró como punto de referencia al suelo con vegetación natural de selva. En el maíz, se observaron disminuciones con el tiempo en el pH, conductividad eléctrica, materia orgánica y calcio intercambiable; ocurrió todo lo contrario en el mango. En el maíz, el fósforo, potasio, sodio, hierro y cobre presentaron una tendencia a disminuir, pero posteriormente se incrementaron a un valor superior al que presentó el suelo de vegetación natural; mientras que en el mango, este comportamiento solo se observó en el cobre, hierro y zinc. Los cationes intercambiables, calcio, potasio, magnesio y sodio, al igual que el manganeso, presentaron valores inferiores en los huertos de mango 30 años de edad, comparados con el suelo de vegetación natural. En el maíz, el fósforo, magnesio, potasio, hierro, manganeso, cobre y zinc, presentaron un valor superior al del suelo con vegetación natural, en el estrato de uno a cinco años, relacionado con el desmonte del terreno, la "quema" de la vegetación y la labranza; pero a excepción del zinc, el valor alcanzado por éstos disminuyó a partir de los siguientes cinco años.

Citotoxicidad del cadmio en hepatocitos de ratón albino y sus posibles implicaciones en ambientes tropicales

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Letty Marcano

2006-06-01

Full Text Available Se realizó un análisis de las alteraciones fenotípicas, estructurales y ultraestructurales inducidas por Cd+2 en hepatocitos de ratón albino suizo. El metal fue suministrado vía oral en solución acuosa de CdCl2 durante 100 días a concentraciones de 50 ppm, 100 ppm y 150 ppm, en los controles la solución de cadmio fue sustituida por agua destilada. Las muestras fueron procesadas utilizando la técnica de inclusión en parafina y teñidas con hematoxilina- eosina para microscopía óptica y por la técnica convencional para microscopía electrónica de transmisión. Identificamos cambios fenotípicos (diferencias entre talla y peso y fisiológicos (debilidad muscular e intranquilidad; a nivel histológico, pérdida de la disposición trabecular y de la arquitectura lobulillar, focos de aglomerados linfocíticos, vacuolización, dilatación de sinosoides y de la vena central. El estudio ultraestructural señala diversas alteraciones tales como: nucléolo con un elevado número de centros fibrilares (50 ppm; voluminosas gotas de lípidos en el citoplasma, retículo endoplasmático rugoso distendido, vacuolización citoplasmática, lisosomas y peroxisomas alterados (100 ppm; núcleos contraídos con cromatina condensada, dilatación en el espacio intracelular y áreas de pérdida mitocondrial y fibrilar (150 ppm. Sugerimos que el cadmio ejerce un efecto tóxico en las células hepáticas el cual se hace más severo con el aumento de la concentración, llevando a la necrosis celular.Cadmium citotoxicity in mice hepatocytes and impications on tropical environments. We analyzed phenotypic, structural and ultrastructural alterations induced by Cd+2 in hepatocytes extracted from Swiss Albino mice. Cadmium was given orally in watery solution of CdCl2 during 100 days at concentrations of 50 ppm, 100 ppm and 150 ppm. In controls, distilled water alone was used. The samples were processed with the paraffin inclusion and hematoxilin-eosin coloration

Tratamiento hidrometalúrgico de los polvos de fundición de cobre. Desarsenifícación de las disoluciones de lixiviación

Directory of Open Access Journals (Sweden)

Alguacil, F. J.

1996-12-01

Full Text Available Copper smelter dusts contain along with this metal, which is amenable for its recovery, a number of other metals (especially arsenic which are considered as toxics. Different alternatives have been proposed for the treatment of such metallurgical residues and among them Hydrometallurgy shows good perspectives for its application in this field. In the present work different hydrometallurgical processes proposed for the treatment of copper smelter dusts are described and evaluated together with different alternatives given for the desarsenification of the leaching solutions.

Los polvos que se producen en los procesos de fundición de cobre contienen, junto a este metal, elemento a recuperar, una serie de metales (especialmente arsénico considerados contaminantes. Se han propuesto diversas alternativas para el tratamiento de estos residuos metalúrgicos y entre estas la Hidrometalurgia presenta buenas perspectivas para su aplicación en este campo. En el presente trabajo se describen y evalúan una serie de procesos hidrometalúrgicos propuestos para el tratamiento de los polvos de fundición de cobre, así como distintas alternativas para la desarsenifícación de las disoluciones de lixiviación.

Zinc electrode - its behaviour in the nickel oxide-zinc accumulator

Energy Technology Data Exchange (ETDEWEB)

1984-01-01

Certain aspects of zinc electrode reaction and behavior are investigated in view of their application to batteries. The properties of the zinc electrode in a battery system are discussed, emphasizing porous structure. Shape change is emphasized as the most important factor leading to limited battery cycle life. It is shown that two existing models of shape change based on electroosmosis and current distribution are unable to consistently describe observed phenomena. The first stages of electrocrystallization are studied and the surface reactions between the silver substrate and the deposited zinc layer are investigated. The reaction mechanism of zinc and amalgamated zinc in an alkaline electrolyte is addressed, and the batter system is studied to obtain information on cycling behavior and on the shape change phenomenon. The effect on cycle behavior of diferent amalgamation techniques of the zinc electrode and several additives is addressed. Impedance measurements on zinc electrodes are considered, and battery behavior is correlated with changes in the zinc electrode during cycling. 193 references.

The bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens

NARCIS (Netherlands)

Veldkamp, T.; Diepen, van J.T.M.; Bikker, P.

2014-01-01

Zinc is an essential trace element for all farm animal species. It is commonly included in animal diets as zinc oxide, zinc sulphate or organically bound zinc. Umicore Zinc Chemicals developed zinc oxide products with different mean particle sizes. Umicore Zinc Chemicals requested Wageningen UR

Determination of silver, gold, zinc and copper in mineral samples by various techniques of instrumental neutron activation analysis; Determinacion de plata, oro, zinc y cobre en muestras minerales mediante diversas tecnicas de analisis por activacion de neutrones instrumental

Energy Technology Data Exchange (ETDEWEB)

Rodriguez R, N. I.; Rios M, C.; Pinedo V, J. L. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Yoho, M.; Landsberger, S., E-mail: neisla126@hotmail.com [University of Texas at Austin, Nuclear Engineering Teaching Laboratory, Austin 78712, Texas (United States)

2015-09-15

Using the method of instrumental neutron activation analysis, mineral exploration samples were analyzed in order to determine the concentrations of silver, gold, zinc and copper; these minerals being the main products of benefit of Tizapa and Cozamin mines. Samples were subjected to various techniques, where the type of radiation and counting methods were chosen based on the specific isotopic characteristics of each element. For calibration and determination of concentrations the comparator method was used, certified standards were subjected to the same conditions of irradiation and measurement that the prospecting samples. The irradiations were performed at the research reactor TRIGA Mark II of the University of Texas at Austin. The silver concentrations were determined by Cyclical Epithermal Neutron Activation Analysis. This method in combination with the transfer pneumatic system allowed a good analytical precision and accuracy in prospecting for silver, from photo peak measurement 657.7 keV of short half-life radionuclide {sup 110}Ag. For the determination of gold and zinc, Epithermal Neutron Activation Analysis was used, the photo peaks analyzed corresponded to the energies 411.8 keV of radionuclide {sup 199}Au and 438.6 keV of metastable radionuclide {sup 69m}Zn. On the other hand, copper quantification was based on the photo peak analysis of 1039.2 keV produced by the short half-life radionuclide {sup 66}Cu, by Thermal Neutron Activation Analysis. The photo peaks measurement corresponding to gold, zinc and copper was performed using a Compton suppression system, which allowed an improvement in the signal to noise relationship, so that better detection limits and low uncertainties associated with the results were obtained. Comparing elemental concentrations the highest values in silver, zinc and copper was for samples of mine Tizapa. Regarding gold values were found in the same range for both mines. To evaluate the precision and accuracy of the methods used

Bioacumulación de cadmio en ostras de la bahía de Cartagena: Bio-accumulation cadmium in oysters of Cartagena bay

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Ganiveth Manjarrez Paba

2008-07-01

Full Text Available La Bahía de Cartagena es una de los cuerpos de agua más contaminados de la ciudad, probablemente debido a las industrias que yacen a su alrededor, algunas de las cuales vierten sus desechos en ella, con poco o ningún tipo de tratamiento. Actualmente, los metales pesados como el cadmio, las operaciones de dragado y relleno, los efluentes térmicos y la sedimentación están causando la degradación de los ecosistemas de la bahía a una tasa alarmante. Esta investigación determinó las concentraciones de cadmio en ostras capturadas en seis puntos estratégicos de la bahía: Álcalis, Bocachica, Caño de Loro, Caño Zapatero, Ciénaga Honda y Zona Franca. Los resultados revelaron que no existen diferencias estadísticamente significativas entre los valores medios de concentración de Cd en ostras en cada uno de los muestreos realizado, y que Ciénaga Honda y Bocachica fueron las estaciones donde se detectó mayor concentración del metal en ostras (25,79 mg Cd/kg y 15,11 mg Cd/kg, respectivamente. Este estudio evidencia el peligro al que están expuestos los consumidores de ostras capturadas en la Bahía de Cartagena, y permite alertar a las autoridades competentes sobre la vigilancia del control en los puntos críticos.Cartagena Bay is one of the most contaminated bodies of water in the city, probably due to the industries around it; some of them dispose of their waste in it, with little or no treatment. Currently, heavy metals such as cadmium, dredging and filling, thermal effluents and sedimentation are causing the degradation of the ecosystem of the bay at an alarming rate. This investigation found concentrations of cadmium in oysters which are caught in six strategic points of the Bay: Álcalis, Bocachica, Caño Loro, Caño Zapatero, Cienaga Honda, and the Free Zone. The results showed that there were no statistically significant differences between the mean values of Cd concentrations in oysters in each one of the samples taken, and that

Effect of consuming zinc-fortified bread on serum zinc and iron status of zinc-deficient women: A double blind, randomized clinical trial

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Akbar Badii

2012-01-01

Full Text Available After iron deficiency, zinc deficiency is the major micronutrient deficiency in developing countries, and staple food fortification is an effective strategy to prevent and improve it among at-risk-populations. No action has been taken to reduce zinc deficiency via flour fortification so far in Iran, and little is known about the influence of zinc fortification of flour on serum zinc and the iron status, and also about the optimum and effective amount of zinc compound that is used in food fortification. The objective of this study is to evaluate the influence of consuming zinc-fortified breads on the zinc and iron status in the blood serum. In this study, three types of bread were prepared from non-fortified and fortified flours, with 50 and 100 ppm elemental zinc in the form of sulfate. Eighty zinc-deficient women aged 19 to 49 years were randomly assigned to three groups; The volunteers received, daily, (1 a non-fortified bread, (2 a high-zinc bread, and (3 a low-zinc bread for one month. Serum zinc and iron were measured by Atomic Absorption before and after the study. Results showed a significant increase in serum zinc and iron levels in all groups (p 0.05. Absorption of zinc and iron in the group that consumed high-zinc bread was significantly greater than that in the group that received low-zinc bread (p < 0.01. It was concluded that fortification of flour with 50-100 ppm zinc was an effective way to achieve adequate zinc intake and absorption in zinc-deficient people. It also appeared that consuming zinc-fortified bread improved iron absorption.

Production of zinc pellets

Science.gov (United States)

Cooper, J.F.

1996-11-26

Uniform zinc pellets are formed for use in batteries having a stationary or moving slurry zinc particle electrode. The process involves the cathodic deposition of zinc in a finely divided morphology from battery reaction product onto a non-adhering electrode substrate. The mossy zinc is removed from the electrode substrate by the action of gravity, entrainment in a flowing electrolyte, or by mechanical action. The finely divided zinc particles are collected and pressed into pellets by a mechanical device such as an extruder, a roller and chopper, or a punch and die. The pure zinc pellets are returned to the zinc battery in a pumped slurry and have uniform size, density and reactivity. Applications include zinc-air fuel batteries, zinc-ferricyanide storage batteries, and zinc-nickel-oxide secondary batteries. 6 figs.

Exigência líquida de zinco, cobre e ferro para cordeiros em pastejo no semiárido = Net requirements of zinc, copper and iron to grazing lambs in semiarid

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Rodrigo de Souza Mendes

2010-07-01

Full Text Available Este trabalho teve por objetivo determinar as exigências líquidas de zinco (Zn, cobre (Cu e ferro (Fe de cordeiros Santa Inês em pastejo na região semiárida. Os animais com peso vivo entre 20 e 30 kg apresentaram conteúdo corporal no peso de corpo vazio (PCV para esses minerais de 60,26 a 76,37 mg kg-1, 10,78 a 16,72 mg kg-1 e 133,44 a 126,98 mg kg-1, respectivamente. Observou-se que com o aumento do PCV, as concentrações de Cu e Zn também aumentavam, enquanto a de Fe diminuía. As exigências líquidas para cordeiros em regime de pastejo variaram de 1,69 a 7,86 mg dia-1 para Cu e 7,20 a 27,4 mg dia-1 para Zn. Os resultados obtidos no presente trabalho, para exigências desses minerais, foram maiores do que as exigências dietéticas recomendadas pelo do NRC (1985, que são de 7 a 11 mg, com máximo de 25 mg e de 20 a 30 mg, com máximo de 750 mg kg-1 de alimento, para Cu e Zn, respectivamente. As exigências líquidas de Fe variaram de 8,46 a 26,66 mg dia-1, e portanto, menores do que as recomendadas pelo NRC (1985 para este mineral que são de 30 a 50 mg kg-1 de alimento.This work had as an aim determine the net requirements of Zinc (Zn, Copper (Cu and Iron (Fe of Santa Inês lambs raised grazing in the semi-arid area. Animals with body weight between 20 e 30 kg showed corporea contents in empty body weight (EBW in these minerals from 60.26 to 76.37 mg kg-1, 10.78 to 16.72 mg kg-1 and from 133.44 to126.98 mg kg-1, respectively. It was observed that increasing the PCV increased Cu and Zn concentration but decreased the Fe concentratiêson. The net requirements for lambs under pasture varied from 1.69 to 7.86 mg day-1 for Cu and from 7.20 to 27.4 mg day-1 for Zn. The results obtained in the present experiment suggest that the dietary requirements in Cu and Zn are higher than those recommended by NRC (1985, between 7 and 11 mg, with a maximum value of 25 mg for Cu and between 20 and 30 mg, with a maximum of 750 mg kg-1 of food for Zn

Cysteine-rich intestinal protein binds zinc during transmucosal zinc transport

International Nuclear Information System (INIS)

Hempe, J.M.; Cousins, R.J.

1991-01-01

The mechanism of zinc absorption has not been delineated, but kinetic studies show that both passive and carrier-mediated processes are involved. The authors have identified a low molecular mass zinc-binding protein in the soluble fraction of rat intestinal mucosa that could function as an intracellular zinc carrier. The protein was not detected in liver or pancreas, suggesting a role specific to the intestine. The protein binds zinc during transmucosal zinc transport and shows signs of saturation at higher luminal zinc concentrations, characteristics consistent with a role in carrier-mediated zinc absorption. Microsequence analysis of the protein purified by gel-filtration HPCL and SDS/PAGE showed complete identity within the first 41 N-terminal amino acids with the deduced protein sequence of cysteine-rich intestinal protein. These investigators showed that the gene for this protein is developmentally regulated in neonates during the suckling period, conserved in many vertebrate species, and predominantly expressed in the small intestine. Cysteine-rich intestinal protein contains a recently identified conserved sequence of histidine and cysteine residues, the LIM motif, which our results suggest confers metal-binding properties that are important for zinc transport and/or functions of this micronutrient

Zinc Signals and Immunity.

Science.gov (United States)

Maywald, Martina; Wessels, Inga; Rink, Lothar

2017-10-24

Zinc homeostasis is crucial for an adequate function of the immune system. Zinc deficiency as well as zinc excess result in severe disturbances in immune cell numbers and activities, which can result in increased susceptibility to infections and development of especially inflammatory diseases. This review focuses on the role of zinc in regulating intracellular signaling pathways in innate as well as adaptive immune cells. Main underlying molecular mechanisms and targets affected by altered zinc homeostasis, including kinases, caspases, phosphatases, and phosphodiesterases, will be highlighted in this article. In addition, the interplay of zinc homeostasis and the redox metabolism in affecting intracellular signaling will be emphasized. Key signaling pathways will be described in detail for the different cell types of the immune system. In this, effects of fast zinc flux, taking place within a few seconds to minutes will be distinguish from slower types of zinc signals, also designated as "zinc waves", and late homeostatic zinc signals regarding prolonged changes in intracellular zinc.

Zinc in Cellular Regulation: The Nature and Significance of "Zinc Signals".

Science.gov (United States)

Maret, Wolfgang

2017-10-31

In the last decade, we witnessed discoveries that established Zn 2+ as a second major signalling metal ion in the transmission of information within cells and in communication between cells. Together with Ca 2+ and Mg 2+ , Zn 2+ covers biological regulation with redox-inert metal ions over many orders of magnitude in concentrations. The regulatory functions of zinc ions, together with their functions as a cofactor in about three thousand zinc metalloproteins, impact virtually all aspects of cell biology. This article attempts to define the regulatory functions of zinc ions, and focuses on the nature of zinc signals and zinc signalling in pathways where zinc ions are either extracellular stimuli or intracellular messengers. These pathways interact with Ca 2+ , redox, and phosphorylation signalling. The regulatory functions of zinc require a complex system of precise homeostatic control for transients, subcellular distribution and traffic, organellar homeostasis, and vesicular storage and exocytosis of zinc ions.

Effect of Consuming Zinc-fortified Bread on Serum Zinc and Iron Status of Zinc-deficient Women: A Double Blind, Randomized Clinical Trial.

Science.gov (United States)

Badii, Akbar; Nekouei, Niloufar; Fazilati, Mohammad; Shahedi, Mohammad; Badiei, Sajad

2012-03-01

After iron deficiency, zinc deficiency is the major micronutrient deficiency in developing countries, and staple food fortification is an effective strategy to prevent and improve it among at-risk-populations. No action has been taken to reduce zinc deficiency via flour fortification so far in Iran, and little is known about the influence of zinc fortification of flour on serum zinc and the iron status, and also about the optimum and effective amount of zinc compound that is used in food fortification. The objective of this study is to evaluate the influence of consuming zinc-fortified breads on the zinc and iron status in the blood serum. In this study, three types of bread were prepared from non-fortified and fortified flours, with 50 and 100 ppm elemental zinc in the form of sulfate. Eighty zinc-deficient women aged 19 to 49 years were randomly assigned to three groups; The volunteers received, daily, (1) a non-fortified bread, (2) a high-zinc bread, and (3) a low-zinc bread for one month. Serum zinc and iron were measured by Atomic Absorption before and after the study. Results showed a significant increase in serum zinc and iron levels in all groups (p 0.05). Absorption of zinc and iron in the group that consumed high-zinc bread was significantly greater than that in the group that received low-zinc bread (p bread improved iron absorption.

Zinc

Science.gov (United States)

... Some early research suggests that zinc supplementation increases sperm count, testosterone levels, and pregnancy rates in infertile men with low testosterone levels. Other research suggests that taking zinc can improve sperm shape in men with moderate enlargement of a ...

Relationship between maternal serum zinc, cord blood zinc and ...

African Journals Online (AJOL)

Background: Adequate in utero supply of zinc is essential for optimal fetal growth because of the role of zinc in cellular division, growth and differentiation. Low maternal serum zinc has been reported to be associated with low birth weight and the later is associated with increased morbidity and mortality in newborns.

BWR zinc addition Sourcebook

International Nuclear Information System (INIS)

Garcia, Susan E.; Giannelli, Joseph F.; Jarvis, Alfred J.

2014-01-01

Boiling Water Reactors (BWRs) have been injecting zinc into the primary coolant via the reactor feedwater system for over 25 years for the purpose of controlling primary system radiation fields. The BWR zinc injection process has evolved since the initial application at the Hope Creek Nuclear Station in 1986. Key transitions were from the original natural zinc oxide (NZO) to depleted zinc oxide (DZO), and from active zinc injection of a powdered zinc oxide slurry (pumped systems) to passive injection systems (zinc pellet beds). Zinc addition has continued through various chemistry regimes changes, from normal water chemistry (NWC) to hydrogen water chemistry (HWC) and HWC with noble metals (NobleChem™) for mitigation of intergranular stress corrosion cracking (IGSCC) of reactor internals and primary system piping. While past reports published by the Electric Power Research Institute (EPRI) document specific industry experience related to these topics, the Zinc Sourcebook was prepared to consolidate all of the experience gained over the past 25 years. The Zinc Sourcebook will benefit experienced BWR Chemistry, Operations, Radiation Protection and Engineering personnel as well as new people entering the nuclear power industry. While all North American BWRs implement feedwater zinc injection, a number of other BWRs do not inject zinc. This Sourcebook will also be a valuable resource to plants considering the benefits of zinc addition process implementation, and to gain insights on industry experience related to zinc process control and best practices. This paper presents some of the highlights from the Sourcebook. (author)

Zinc at glutamatergic synapses.

Science.gov (United States)

Paoletti, P; Vergnano, A M; Barbour, B; Casado, M

2009-01-12

It has long been known that the mammalian forebrain contains a subset of glutamatergic neurons that sequester zinc in their synaptic vesicles. This zinc may be released into the synaptic cleft upon neuronal activity. Extracellular zinc has the potential to interact with and modulate many different synaptic targets, including glutamate receptors and transporters. Among these targets, NMDA receptors appear particularly interesting because certain NMDA receptor subtypes (those containing the NR2A subunit) contain allosteric sites exquisitely sensitive to extracellular zinc. The existence of these high-affinity zinc binding sites raises the possibility that zinc may act both in a phasic and tonic mode. Changes in zinc concentration and subcellular zinc distribution have also been described in several pathological conditions linked to glutamatergic transmission dysfunctions. However, despite intense investigation, the functional significance of vesicular zinc remains largely a mystery. In this review, we present the anatomy and the physiology of the glutamatergic zinc-containing synapse. Particular emphasis is put on the molecular and cellular mechanisms underlying the putative roles of zinc as a messenger involved in excitatory synaptic transmission and plasticity. We also highlight the many controversial issues and unanswered questions. Finally, we present and compare two widely used zinc chelators, CaEDTA and tricine, and show why tricine should be preferred to CaEDTA when studying fast transient zinc elevations as may occur during synaptic activity.

Evaluación in vitro de tabletas orales de complejos de cobre con antiinflamatorios no esteroideos

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Julie Fernanda Benavides Arévalo

Full Text Available Introducción: los antiinflamatorios no esteroideos (AINES, son un grupo diverso y químicamente heterogéneo de fármacos analgésicos, antipiréticos y antiinflamatorios; sin embargo, su funcionamiento se ve afectado por su baja solubilidad acuosa y por la incidencia de efectos secundarios gastrointestinales. Como una alternativa a este problema, la formulación de tabletas orales con complejos de cobre con AINES muestra un adecuado comportamiento in vitro y podría tener efectos secundarios reducidos comparados con el fármaco antiinflamatorio no complejado. Objetivo: evaluar los procesos de desintegración y de disolución de tabletas orales de complejos de cobre con AINES. Métodos: luego de la síntesis y la caracterización instrumental de los complejos, se evaluó por microscopia óptica el efecto de la morfología, el tamaño de partícula y las características superficiales en el proceso de disolución; estos resultados fueron considerados para la formulación de los complejos y permitieron junto con la adecuada elección de un desintegrarte, un modificador de flujo, un lubricante y un aglutinante, la obtención de tabletas por compresión directa. Finalmente, en los comprimidos se evaluaron propiedades fisicomecánicas y los procesos de desintegración y disolución. Resultados: las tabletas de los complejos mostraron tiempos de desintegración entre 5 y 15 min y una liberación in vitro del 75 al 93 %. Conclusiones: la disolución de los AINES se vio favorecida por la formación de complejos, el menor tamaño de partícula, la presencia de poros y grietas en la superficie de las partículas y la inclusión de excipientes para la formulación de tabletas orales.

Evaluación de la Corrosión del Cable de Cobre Utilizado en Sistema de Aterrizamiento del ICE - Costa Rica

OpenAIRE

Tres, G.; Saborio, E.

2004-01-01

En la presente investigación se evaluó principalmente la cinética de corrosión del cable de cobre empleado en las mallas de aterrizamiento de sistemas de pararrayos en plantas del Instituto Costarricense de Electricidad. Se aplicó tanto el método electroquímico de resistencia de polarización linear (LPR; de sus siglaas en inglés) como el gravimétrico. Se realizaron ensayos de laboratorio y de campo, empleando como electrolitos dos productos comercialmente disponibles para el aterrizamiento de...

Tracing of Zinc Nanocrystals in the Anterior Pituitary of Zinc-Deficient Wistar Rats.

Science.gov (United States)

Kuldeep, Anjana; Nair, Neena; Bedwal, Ranveer Singh

2017-06-01

The aim of this study was to trace zinc nanocrystals in the anterior pituitary of zinc-deficient Wistar rats by using autometallographic technique. Male Wistar rats (30-40 days of age, pre-pubertal period) of 40-50 g body weight were divided into the following: the ZC (zinc control) group-fed with 100 ppm zinc in diet, the ZD (zinc-deficient) group-fed with zinc-deficient (1.00 ppm) diet and the PF (pair-fed) group-received 100 ppm zinc in diet. The experiments were set for 2 and 4 weeks. Pituitary was removed and processed for the autometallographic technique. The control and pair-fed groups retained their normal morphological features. However, male Wistar rats fed on zinc-deficient diet for 2 and 4 weeks displayed a wide range of symptoms such as significant (P zinc nanocrystals in the nuclei. The present findings suggest that the dietary zinc deficiency causes decreased intensity of zinc nanocrystals localization and their distribution in the pituitary thereby contributing to the dysfunction of the pituitary of the male Wistar rats. The severity of zinc deficiency symptoms progressed after the second week of the experiment. Decreased intensity of zinc nanocrystals attenuates the pituitary function which would exert its affect on other endocrine organs impairing their functions indicating that the metabolic regulation of pituitary is mediated to a certain extent by zinc and/or hypothalamus-hypophysial system which also reflects its essentiality during the period of growth.

Copper desorption in a soil with variable charge Dessorção de cobre em solo com carga variável

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José Carlos Casagrande

2004-04-01

Full Text Available Adsorption processes of heavy metals in soils have been more extensively studied than desorption, in spite of this latter process being related to nutrient bioavailability in the soil solution. Copper desorption from surface (0-0.2 m and subsurface (1.0 - 1.2 m samples of an Anionic Acrudox was studied at two pH values (4.5 and 7.5. Soil samples were incubated with Cu rates varying from 0 to 400 mg kg-1, during 4 and 12 weeks, in the presence of CaCl2 as support electrolyte at concentrations of 0.01 and 0.001 mol L-1. Complete soil adsorption of added Cu was observed at pH 7.5 in all incubation periods, indicating that a 24h-shaking period was enough to reach equilibrium and maximum adsorption. Copper adsorption varied with the incubation period and was much lower at pH 4.5 than at pH 7.5, after the 24 hour-incubation period. After 4 and 12 weeks, Cu adsorption values were higher and similar for all soil samples, irrespective of pH or depth of sampling. The effect of the incubation period on soil Cu adsorption surpassed the pH effect for all Cu rates. The hysteresis was expressive, suggesting that Cu enhances high-energy bonds with the soil colloids. Calcium chloride was not efficient in promoting native soil Cu desorption in the studied concentrations.A adsorção de metais pesados aos solos é mais estudada do que sua dessorção. No entanto, o processo de dessorção está diretamente relacionado à disponibilidade dos elementos às plantas. A dessorção de cobre em amostras superficiais (0-0,2 m e subsuperficiais (1,0-1,2 m de um Latossolo Vermelho acriférrico foi estudada em dois valores de pH (4,5 e 7,5. Foram adicionados até 400 mg kg-1 de Cu em amostras incubadas por 4 e 12 semanas, tendo o CaCl2 como eletrólito suporte nas concentrações de 0,01 e 0,001 mol L-1. No pH mais elevado (7,5, em todos os períodos de incubação, as amostras adsorveram praticamente todo o cobre adicionado, indicando que o tempo de 24 h de agitação para

PREPARATION OF ZINC ENRICHED YEAST (SACCHAROMYCES CEREVISIAE BY CULTIVATION WITH DIFFERENT ZINC SALTS

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Ľuboš Harangozo

2012-02-01

Full Text Available The yeast Saccharomyces cerevisiae is the best known microorganism and therefore widely used in many branches of industry. This study aims to investigate the accumulation of three inorganic zinc salts. Our research presents the ability of this yeast to absorb zinc from liquid medium and such enriched biomass use as a potential source of microelements in animal and/or human nutrition. It was found that the addition of different zinc forms, i.e. zinc nitrate, zinc sulphate and zinc chloride in fixed concentrations of 0, 25, 50 and 100 mg.100 ml-1 did not affect the amount of dry yeast biomass yielded, i.e. 1.0 – 1.2 g of yeast cells from 100 ml of cultivation medium, while higher presence of zinc solutions caused significantly lower yield of yeast biomass. The highest amount of zinc in yeast cells was achieved when added in the form of zinc nitrate in concentration of 200 mg.100 ml-1 YPD medium. The increment of intracellular zinc was up to 18.5 mg.g-1 of yeast biomass.

The study and microstructure analysis of zinc and zinc oxide

Czech Academy of Sciences Publication Activity Database

Luptáková, Natália; Pešlová, F.; Kliber, J.

2015-01-01

Roč. 54, č. 1 (2015), s. 43-46 ISSN 0543-5846 Grant - others:KEGA(SK) KEGA 007 TnUAD-4/2013 Institutional support: RVO:68081723 Keywords : zinc * production of zinc oxide * microstructure * chemical composition * zinc slag Subject RIV: JG - Metal lurgy Impact factor: 0.959, year: 2014

Zinc Biochemistry: From a Single Zinc Enzyme to a Key Element of Life12

Science.gov (United States)

Maret, Wolfgang

2013-01-01

The nutritional essentiality of zinc for the growth of living organisms had been recognized long before zinc biochemistry began with the discovery of zinc in carbonic anhydrase in 1939. Painstaking analytical work then demonstrated the presence of zinc as a catalytic and structural cofactor in a few hundred enzymes. In the 1980s, the field again gained momentum with the new principle of “zinc finger” proteins, in which zinc has structural functions in domains that interact with other biomolecules. Advances in structural biology and a rapid increase in the availability of gene/protein databases now made it possible to predict zinc-binding sites from metal-binding motifs detected in sequences. This procedure resulted in the definition of zinc proteomes and the remarkable estimate that the human genome encodes ∼3000 zinc proteins. More recent developments focus on the regulatory functions of zinc(II) ions in intra- and intercellular information transfer and have tantalizing implications for yet additional functions of zinc in signal transduction and cellular control. At least three dozen proteins homeostatically control the vesicular storage and subcellular distribution of zinc and the concentrations of zinc(II) ions. Novel principles emerge from quantitative investigations on how strongly zinc interacts with proteins and how it is buffered to control the remarkably low cellular and subcellular concentrations of free zinc(II) ions. It is fair to conclude that the impact of zinc for health and disease will be at least as far-reaching as that of iron. PMID:23319127

An experimental study of the retention of zinc, zinc-cadmium mixture and zinc-65 in the presence of cadmium in Anguilla anguilla (L.)

International Nuclear Information System (INIS)

Pally, Monique; Foulquier, Luc

1976-07-01

Zinc uptake was studied in eels in fresh water, using stable zinc, a zinc-cadmium mixture, and zinc 65 in the presence of small amounts of cadmium. The zinc content in the eel began to increase after 45 days only, and reached approximately 85 ppm after 76 days in water initially containing 5ppm of zinc. At the conclusion of the experiment (76 days), the body organs could be classified in decreasing order in zinc content (in ppm): kidneys (152), skeleton (133), skin (129), muscles (89), head (80), gills (78), digestive tract (77), liver (63) spleen-heart-air bladder (32), and mucus (15). A comparison of experimental results obtained with the zinc-cadmium mixture and cadmium alone showed that zinc decreased the cadmium content of all organs except the gills. The presence of cadmium in water did not inhibit zinc uptake. As cadmium content in water increased, then zinc content in the digestive tract and the kidneys decreased and in all cases remained lower than when zinc alone was present. In the presence of cadmium the percentage of zinc in the kidneys was always lower than the value obtained for zinc alone, and that of the digestive tract did not increase. Contamination of eels treated with 18 and 50ppb of cadmium for 29 days, then contaminated by zinc-65 (5μCi/l) while maintaining the same low cadmium content, showed no significant difference in zinc 65 uptake in the two groups. The same applied to the body organs, and particularly the digestive tract and kidneys, where the highest activity levels were observed. By weight, muscles represented approximately 30% of the total contamination after 45 days [fr

Effect of zinc sources on yield and utilization of zinc in rice-wheat sequence

International Nuclear Information System (INIS)

Deb, D.L.

1990-01-01

A field experiment was conducted on an inceptisol of Delhi to evaluate three sources of zinc, namely, zinc sulphate, zincated urea and zinc oxide on yield and utilization of zinc in rice-wheat sequence. Results indicated that, amongst the three zinc sources, zinc sulphate and zincated urea gave the best performance in increasing the grain yield of rice whereas zinc oxide depressed the grain yield of wheat significantly when compared to other treatments. The highest Zn derived from fertilizer and its utilization was obtained with zinc sulphate for both rice and wheat crops. (author). 9 refs., 4 tabs

Zinc blotting assay for detection of zinc binding prolamin in barley (Hordeum vulgare) grain

DEFF Research Database (Denmark)

Uddin, Mohammad Nasir; Nielsen, Ane Langkilde-Lauesen; Vincze, Eva

2014-01-01

In plants, zinc is commonly found bound to proteins. In barley (Hordeum vulgare), major storage proteins are alcohol-soluble prolamins known as hordeins, and some of them have the potential to bind or store zinc. 65Zn overlay and blotting techniques have been widely used for detecting zinc......-binding protein. However, to our knowledge so far this zinc blotting assay has never been applied to detect a prolamin fraction in barley grains. A radioactive zinc (65ZnCl2) blotting technique was optimized to detect zinc-binding prolamins, followed by development of an easy-to-follow nonradioactive colorimetric...... zinc blotting method with a zinc-sensing dye, dithizone. Hordeins were extracted from mature barley grain, separated by SDS-PAGE, blotted on a membrane, renatured, overlaid, and probed with zinc; subsequently, zinc-binding specificity of certain proteins was detected either by autoradiography or color...

Modelización de la deformación en caliente de un cobre puro comercial

Directory of Open Access Journals (Sweden)

García, V. G.

2001-04-01

Full Text Available The objective of the study is to model the flow curve at high temperature of a commercialpurity copper which contains 297 ppm of phosphorus. For this purpose a theoretical model is applied to derive a constitutive equation that reliably predicts the behaviour at higher strain rates than experimentally tested. The test temperature range was from 873 K to 1223 K in increments of 50 K, using six true strain rates at every temperature, which span from 0.3 s^-1 to 0.001 s^-1 The hot flow tests were performed on a copper with a relatively large grain size (637 µm but of similar scale to pertinent industrial processes. This metal presents two antagonistic phenomena during the hot working: strain hardening and softening by dynamic restoration, which in turns can be divided into dynamic recovery and dynamic recrystallization. A quantification of the mentioned mechanisms is done through the use of physically based constitutive equations.

El objetivo de este estudio es modelizar la curva de fluencia a alta temperatura de un cobre de pureza comercial conteniendo 297 ppm de fósforo. Todo ello, con objeto de obtener una ecuación constitutiva que fiablemente prediga el comportamiento a otras velocidades de deformación diferentes de las posibles experimentalmente. El intervalo de temperaturas en los que se efectuaron ensayos fue desde 873 K a 1.223 K en incrementos de 50 K, utilizando seis velocidades de deformación verdadera a cada temperatura, las cuales iban desde 0,3 s^-1 hasta 0,001 s^-1 Los ensayos de deformación en caliente fueron realizados en un cobre con un tamaño de grano relativamente grande (637 μm pero escalarmente similar al de procesos industriales relevantes. Durante la deformación en caliente, el metal presenta dos fenómenos antagonistas, a saber: endurecimiento por deformación y ablandamiento por recuperación dinámica, el cual, a su vez, puede desglosarse en restauración y

FITOEXTRACCIÓN DE PLOMO Y CADMIO EN SUELOS CONTAMINADOS USANDO QUELITE (Amaranthus hybridus L. Y MICORRIZAS

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H. G. Ortiz-Cano

2009-01-01

Full Text Available Las actividades mineras y metalúrgicas practicadas en la Comarca Lagunera, México han contaminado el suelo, el aire y el agua. El uso de plantas es una de las estrategias para la remediación de suelos contaminados con metales pesados. Sin embargo, son pocos los estudios sobre remediación con plantas de zonas áridas y su asociación con micorrizas. El objetivo de este estudio fue evaluar la capacidad extractora de Plomo (Pb y Cadmio (Cd del quelite (Amaranthus hybridus L. al adicionar una mezcla de micorrizas arbusculares (Entrophospora columbiana, Glomus intraradices, G. etunicatum, G clarum al sustrato contaminado con Pb o Cd. Dos experimentos, uno por cada metal, con diseño experimental de bloques al azar con cuatro repeticiones fueron desarrollados. En el primero se adicionaron tres cantidades de micorrizas (0, 2.5 y 5.0 g·kg-1 en suelos con 300 mg·kg-1 de Pb. En el segundo experimento, las mismas cantidades de micorrizas fueron probadas en suelos contaminados con 15 mg·kg-1 de Cd. Las concentraciones de Pb y Cd en raíz, hoja y tallo a los 65, 95 y 125 días de edad de la planta se determinaron con un espectrofotómetro de absorción atómica. Los resultados indican que la adición de micorrizas incrementó significativamente (P<0.05 la concentración de Pb y Cd en raíz, tallo y hoja de quelite. Las concentraciones de estos metales se incrementaron significativamente conforme la edad de la planta.

Neodymium conversion layers formed on zinc powder for improving electrochemical properties of zinc electrodes

International Nuclear Information System (INIS)

Zhu Liqun; Zhang Hui; Li Weiping; Liu Huicong

2008-01-01

Zinc powder, as active material of secondary alkaline zinc electrode, can greatly limit the performance of zinc electrode due to corrosion and dendritic growth of zinc resulting in great capacity-loss and short cycle life of the electrode. This work is devoted to modification study of zinc powder with neodymium conversion films coated directly onto it using ultrasonic immersion method for properties improvement of zinc electrodes. Scanning electron microscopy and other characterization techniques are applied to prove that neodymium conversion layers are distributing on the surface of modified zinc powder. The electrochemical performance of zinc electrodes made of such modified zinc powder is investigated through potentiodynamic polarization, potentiostatic polarization and cyclic voltammetry. The neodymium conversion films are found to have a significant effect on inhibition corrosion capability of zinc electrode in a beneficial way. It is also confirmed that the neodymium conversion coatings can obviously suppress dendritic growth of zinc electrode, which is attributed to the amelioration of deposition state of zinc. Moreover, the results of cyclic voltammetry reveal that surface modification of zinc powder enhances the cycle performance of the electrode mainly because the neodymium conversion films decrease the amounts of ZnO or Zn(OH) 2 dissolved in the electrolyte

Zinc in human serum

International Nuclear Information System (INIS)

Kiilerich, S.

1987-01-01

The zinc ion is essential for the living organism. Many pathological conditions have been described as a consequence of zinc deficiency. As zinc constitutes less than 0.01 per cent of the body weight, it conventionally belongs to the group of trace elements. The method of atomic absorption spectrophotometry is used to measure the concentration of zinc in serum and urine from healthy persons. The assumptions of the method is discussed. The importance of proteinbinding, diet and the diurnal variation of serum zinc concentration is presented. Serum versus plasma zinc concentration is discussed. Reference serum zinc values from 104 normal subjects are given. Zinc in serum is almost entirely bound to proteins. A preliminary model for the estimation of the distribution of zinc between serum albumin and α 2 -macroglobulin is set up. This estimate has been examined by an ultracentrufugation method. The binding of zinc to a α 2 -macroglobulin in normal persons is appoximately 7 per cent, in patients with cirrhosis of the liver of alcoholic origin approximately 6 per cent, in patients with insulin dependent diabetes mellitus approximately 5 per cent, and in patients with chronic renal failure approximately 2 per cent. It is concluded, therefore, that for clinical purposes it is sufficient to use the concentration of total serum zinc corrected for the concentration of serum albumin. (author)

Impact of residual elements on zinc quality in the production of zinc oxide

Czech Academy of Sciences Publication Activity Database

Luptáková, Natália; Dymáček, Petr; Pešlová, F.; Jurkovič, Z.; Barborák, O.; Stodola, J.

2016-01-01

Roč. 55, č. 3 (2016), s. 407-410 ISSN 0543-5846 Institutional support: RVO:68081723 Keywords : zinc * metallography * microstructure of zinc * zinc oxide * production of zinc oxide Subject RIV: JG - Metallurgy Impact factor: 0.959, year: 2014

Importancia de la forma química y de la matriz del sustrato en la toxicidad por cobre en Noticastrum sericeum (Less. Less. ex Phil Importance of the chemical form and type of substrate for copper toxicity in Noticastrum sericeum (Less. Less. ex Phil

Directory of Open Access Journals (Sweden)

ROSANNA GINOCCHIO

2002-09-01

Full Text Available El aumento de la concentración de cobre en los suelos debido a distintas fuentes antrópicas puede producir efectos de toxicidad en las especies vegetales sensibles. Sin embargo, se ha postulado que diversos factores edáficos podrían determinar la biodisponibilidad del cobre y, por lo tanto, la intensidad del efecto fitotóxico, tales como el contenido de materia orgánica y el pH del suelo, además del grado de solubilidad de la forma química en la cual el cobre es incorporado. Para determinar la importancia de la capacidad tamponante del sustrato de crecimiento y de la forma química del cobre en el grado de fitotoxicidad, se expuso plántulas de una especie sensible a concentraciones crecientes de cobre, incorporado como una sal muy soluble en agua (CuSO4 o como una sal muy poco soluble en agua (CuO, a un sustrato sólido altamente tamponante, rico en materia orgánica y de pH neutro (compost comercial y a una solución poco tamponante de 2 mmoles L-1 de nitrato de calcio, sin materia orgánica y moderadamente ácida. Se detectaron efectos significativos de toxicidad por cobre en las raíces de las plántulas cultivadas en el sustrato líquido, independientemente de la forma química y de la concentración adicionadas, expresados por una inhibición en el crecimiento de las raíces primarias y en el número de raíces secundarias formadas. Como se esperaba, los efectos de toxicidad fueron menos marcados en el vástago, pero el CuSO4 inhibió significativamente la producción de hojas nuevas en las plantas crecidas en solución, independientemente de la concentración, mientras que el CuO sólo redujo significativamente la producción de hojas al ser agregado a alta concentración. No se detectó efectos de toxicidad en las plantas crecidas en el sustrato sólido, independientemente de la sal de cobre y de la concentración adicionadas, debido a que su alto contenido de materia orgánica y pH neutro resultaron en una baja disponibilidad de

Cyclic AMP Pathway Activation and Extracellular Zinc Induce Rapid Intracellular Zinc Mobilization in Candida albicans

Science.gov (United States)

Kjellerup, Lasse; Winther, Anne-Marie L.; Wilson, Duncan; Fuglsang, Anja T.

2018-01-01

Zinc is an essential micronutrient, required for a range of zinc-dependent enzymes and transcription factors. In mammalian cells, zinc serves as a second messenger molecule. However, a role for zinc in signaling has not yet been established in the fungal kingdom. Here, we used the intracellular zinc reporter, zinbo-5, which allowed visualization of zinc in the endoplasmic reticulum and other components of the internal membrane system in Candida albicans. We provide evidence for a link between cyclic AMP/PKA- and zinc-signaling in this major human fungal pathogen. Glucose stimulation, which triggers a cyclic AMP spike in this fungus resulted in rapid intracellular zinc mobilization and this “zinc flux” could be stimulated with phosphodiesterase inhibitors and blocked via inhibition of adenylate cyclase or PKA. A similar mobilization of intracellular zinc was generated by stimulation of cells with extracellular zinc and this effect could be reversed with the chelator EDTA. However, zinc-induced zinc flux was found to be cyclic AMP independent. In summary, we show that activation of the cyclic AMP/PKA pathway triggers intracellular zinc mobilization in a fungus. To our knowledge, this is the first described link between cyclic AMP signaling and zinc homeostasis in a human fungal pathogen. PMID:29619016

Reactivation in vitro of zinc-requiring apo-enzymes by rat liver zinc-thionein

OpenAIRE

Udom, Albert O.; Brady, Frank O.

1980-01-01

The ability of rat liver zinc-thionein to donate its metal to the apo-enzymes of the zinc enzymes horse liver alcohol dehydrogenase, yeast aldolase, thermolysin, Escherichia coli alkaline phosphatase and bovine erythrocyte carbonic anhydrase was investigated. Zinc-thionein was as good as, or better than, ZnSO4, Zn(CH3CO2)2 or Zn(NO3)2 in donating its zinc to these apo-enzymes. Apo-(alcohol dehydrogenase) could not be reactivated by zinc salts or by zinc-thionein. Incubation of the other apo-e...

Br2 molecular elimination in photolysis of (COBr)2 at 248 nm by using cavity ring-down absorption spectroscopy: A photodissociation channel being ignored

International Nuclear Information System (INIS)

Wu, Chia-Ching; Lin, Hsiang-Chin; Chang, Yuan-Bin; Tsai, Po-Yu; Yeh, Yu-Ying; Fan, He; Lin, King-Chuen; Francisco, J. S.

2011-01-01

A primary dissociation channel of Br 2 elimination is detected following a single-photon absorption of (COBr) 2 at 248 nm by using cavity ring-down absorption spectroscopy. The technique contains two laser beams propagating in a perpendicular configuration. The tunable laser beam along the axis of the ring-down cell probes the Br 2 fragment in the B 3 Π ou + -X 1 Σ g + transition. The measurements of laser energy- and pressure-dependence and addition of a Br scavenger are further carried out to rule out the probability of Br 2 contribution from a secondary reaction. By means of spectral simulation, the ratio of nascent vibrational population for v = 0, 1, and 2 levels is evaluated to be 1:(0.65 ± 0.09):(0.34 ± 0.07), corresponding to a Boltzmann vibrational temperature of 893 ± 31 K. The quantum yield of the ground state Br 2 elimination reaction is determined to be 0.11 ± 0.06. With the aid of ab initio potential energy calculations, the pathway of molecular elimination is proposed on the energetic ground state (COBr) 2 via internal conversion. A four-center dissociation mechanism is followed synchronously or sequentially yielding three fragments of Br 2 + 2CO. The resulting Br 2 is anticipated to be vibrationally hot. The measurement of a positive temperature effect supports the proposed mechanism.

Br2 molecular elimination in photolysis of (COBr)2 at 248 nm by using cavity ring-down absorption spectroscopy: a photodissociation channel being ignored.

Science.gov (United States)

Wu, Chia-Ching; Lin, Hsiang-Chin; Chang, Yuan-Bin; Tsai, Po-Yu; Yeh, Yu-Ying; Fan, He; Lin, King-Chuen; Francisco, J S

2011-12-21

A primary dissociation channel of Br(2) elimination is detected following a single-photon absorption of (COBr)(2) at 248 nm by using cavity ring-down absorption spectroscopy. The technique contains two laser beams propagating in a perpendicular configuration. The tunable laser beam along the axis of the ring-down cell probes the Br(2) fragment in the B(3)Π(ou)(+)-X(1)Σ(g)(+) transition. The measurements of laser energy- and pressure-dependence and addition of a Br scavenger are further carried out to rule out the probability of Br(2) contribution from a secondary reaction. By means of spectral simulation, the ratio of nascent vibrational population for v = 0, 1, and 2 levels is evaluated to be 1:(0.65 ± 0.09):(0.34 ± 0.07), corresponding to a Boltzmann vibrational temperature of 893 ± 31 K. The quantum yield of the ground state Br(2) elimination reaction is determined to be 0.11 ± 0.06. With the aid of ab initio potential energy calculations, the pathway of molecular elimination is proposed on the energetic ground state (COBr)(2) via internal conversion. A four-center dissociation mechanism is followed synchronously or sequentially yielding three fragments of Br(2) + 2CO. The resulting Br(2) is anticipated to be vibrationally hot. The measurement of a positive temperature effect supports the proposed mechanism.

Transformation of zinc hydroxide chloride monohydrate to crystalline zinc oxide.

Science.gov (United States)

Moezzi, Amir; Cortie, Michael; McDonagh, Andrew

2016-04-25

Thermal decomposition of layered zinc hydroxide double salts provides an interesting alternative synthesis for particles of zinc oxide. Here, we examine the sequence of changes occurring as zinc hydroxide chloride monohydrate (Zn5(OH)8Cl2·H2O) is converted to crystalline ZnO by thermal decomposition. The specific surface area of the resultant ZnO measured by BET was 1.3 m(2) g(-1). A complicating and important factor in this process is that the thermal decomposition of zinc hydroxide chloride is also accompanied by the formation of volatile zinc-containing species under certain conditions. We show that this volatile compound is anhydrous ZnCl2 and its formation is moisture dependent. Therefore, control of atmospheric moisture is an important consideration that affects the overall efficiency of ZnO production by this process.

Influence of soil zinc concentrations on zinc sensitivity and functional diversity of microbial communities

International Nuclear Information System (INIS)

Lock, K.; Janssen, C.R.

2005-01-01

Pollution induced community tolerance (PICT) is based on the phenomenon that toxic effects reduce survival of the most sensitive organisms, thus increasing community tolerance. Community tolerance for a contaminant is thus a strong indicator for the presence of that contaminant at the level of adverse concentrations. Here we assessed PICT in 11 soils contaminated with zinc runoff from galvanised electricity pylons and 11 reference soils sampled at 10 m distance from these pylons. Using PICT, the influence of background concentration and bioavailability of zinc on zinc sensitivity and functional diversity of microbial communities was assessed. Zinc sensitivity of microbial communities decreased significantly with increasing zinc concentrations in pore water and calcium chloride extracted fraction while no significant relationship was found with total zinc concentration in the soil. It was also found that functional diversity of microbial communities decreased with increasing zinc concentrations, indicating that increased tolerance is indeed an undesirable phenomenon when environmental quality is considered. The hypothesis that zinc sensitivity of microbial communities is related to background zinc concentration in pore water could not be confirmed. - Zinc sensitivity of microbial communities and functional diversity decrease with increasing zinc concentration in the pore water

Electrochemical synthesis and characterization of zinc carbonate and zinc oxide nanoparticles

Science.gov (United States)

Pourmortazavi, Seied Mahdi; Marashianpour, Zahra; Karimi, Meisam Sadeghpour; Mohammad-Zadeh, Mohammad

2015-11-01

Zinc oxide and its precursor i.e., zinc carbonate is widely utilized in various fields of industry, especially in solar energy conversion, optical, and inorganic pigments. In this work, a facile and clean electrodeposition method was utilized for the synthesis of zinc carbonate nanoparticles. Also, zinc oxide nanoparticles were produced by calcination of the prepared zinc carbonate powder. Zinc carbonate nanoparticles with different sizes were electrodeposited by electrolysis of a zinc plate as anode in the solution of sodium carbonate. It was found that the particle size of zinc carbonate might be tuned by process parameters, i.e., electrolysis voltage, carbonate ion concentration, solvent composition and stirring rate of the electrolyte solution. An orthogonal array design was utilized to identify the optimum experimental conditions. The experimental results showed that the minimum size of the electrodeposited ZnCO3 particles is about 24 nm whereas the maximum particle size is around 40 nm. The TG-DSC studies of the nanoparticles indicated that the main thermal degradation of ZnCO3 occurs in two steps over the temperature ranges of 150-250 and 350-400 °C. The electrosynthesized ZnCO3 nanoparticles were calcined at the temperature of 600 °C to prepare ZnO nanoparticles. The prepared ZnCO3 and ZnO nanoparticles were characterized by SEM, X-ray diffraction (XRD), and FT-IR techniques.

The relative efficiency of zinc carriers on growth and zinc nutrition of corn

International Nuclear Information System (INIS)

Prasad, B.; Sinha, K.

1981-01-01

A comparison of different zinc carriers showed that application of Zn-DTPA, Zn-EDTA, Zn-fulvate and ZnSO 4 significantly increased the dry matter yield and zinc uptake by corn over the control treatment where no zinc was applied. The chelates in particular enhanced to a greater extent the uptake of both native and applied sources than that observed with ZnSO 4 as the zinc carrier. Both the dry matter yield and zinc uptake by corn showed a positive and significant relationship with self-diffusion coefficient of zinc showing thereby that diffusion contributed mainly the supply of Zn from the ambient soil matrix to plant roots. The effectiveness of the chelates varied depending on their capacity to retain Zn in a soluble form in the soil solution. It is evident that zinc nutrition of plants in alkaline and calcareous soils can be more effectively regulated by both synthetic and natural chelates or organic manures which contain substantial amount of complexed zinc. (orig.)

Aportaciones de estaño-plata y estaño-cobre en la soldadura blanda por capilaridad de canalizaciones de cobre

Directory of Open Access Journals (Sweden)

Durán, J.

2001-04-01

Full Text Available It is studied the influence of the type of alloy used as filling material on the defects of the soldering joints in copper piping installations, which induce the fluid leak of the systems. The different eutectic temperatures and solidus-liquidus ranges of these alloys, require the setting of the soldering heat input in each case to obtain the suitable capillarity features and alloying temperatures to achieve for the correct formation of the bondings. Most defects in the joints are demonstrated to be generated by bad dossification of thermal inputs, which led depending on the filler alloy used to variations in its fluidity that may produce penetration failures in the bonds or insufficient consistency for the filling of the joints.

Se estudia la influencia del tipo de aleación utilizada como material de aporte, en los defectos resultantes en las uniones de soldadura blanda por capilaridad en instalaciones de tubería de cobre, que provocan la fuga del fluido de las canalizaciones. Las diferentes temperaturas eutécticas y de los rangos solidus-líquidus de estos tipos de aleaciones, obligan a ajustar los aportes del calor de soldeo en cada caso para conseguir las propiedades de capilaridad y temperaturas de aleación adecuadas para la correcta formación de las soldaduras. Se demuestra que, la mayoría de los defectos en las uniones se produce por mala dosificación de los aportes térmicos, lo que conduce, dependiendo de la aleación utilizada, a variaciones en la fluidez de la aportación que pueden dar lugar a fallos en la penetración de las juntas o a insuficiente consistencia para el relleno de las uniones.

Zinc triggers microglial activation.

Science.gov (United States)

Kauppinen, Tiina M; Higashi, Youichirou; Suh, Sang Won; Escartin, Carole; Nagasawa, Kazuki; Swanson, Raymond A

2008-05-28

Microglia are resident immune cells of the CNS. When stimulated by infection, tissue injury, or other signals, microglia assume an activated, "ameboid" morphology and release matrix metalloproteinases, reactive oxygen species, and other proinflammatory factors. This innate immune response augments host defenses, but it can also contribute to neuronal death. Zinc is released by neurons under several conditions in which microglial activation occurs, and zinc chelators can reduce neuronal death in animal models of cerebral ischemia and neurodegenerative disorders. Here, we show that zinc directly triggers microglial activation. Microglia transfected with a nuclear factor-kappaB (NF-kappaB) reporter gene showed a severalfold increase in NF-kappaB activity in response to 30 microm zinc. Cultured mouse microglia exposed to 15-30 microm zinc increased nitric oxide production, increased F4/80 expression, altered cytokine expression, and assumed the activated morphology. Zinc-induced microglial activation was blocked by inhibiting NADPH oxidase, poly(ADP-ribose) polymerase-1 (PARP-1), or NF-kappaB activation. Zinc injected directly into mouse brain induced microglial activation in wild-type mice, but not in mice genetically lacking PARP-1 or NADPH oxidase activity. Endogenous zinc release, induced by cerebral ischemia-reperfusion, likewise induced a robust microglial reaction, and this reaction was suppressed by the zinc chelator CaEDTA. Together, these results suggest that extracellular zinc triggers microglial activation through the sequential activation of NADPH oxidase, PARP-1, and NF-kappaB. These findings identify a novel trigger for microglial activation and a previously unrecognized mechanism by which zinc may contribute to neurological disorders.

Effects of dietary supplementation with tribasic zinc sulfate or zinc sulfate on growth performance, zinc content and expression of zinc transporters in young pigs.

Science.gov (United States)

Deng, Bo; Zhou, Xihong; Wu, Jie; Long, Ciming; Yao, Yajun; Peng, Hongxing; Wan, Dan; Wu, Xin

2017-10-01

An experiment was conducted to compare the effects of zinc sulfate (ZS) and tribasic zinc sulfate (TBZ) as sources of supplemental zinc on growth performance, serum zinc (Zn) content and messenger RNA (mRNA) expression of Zn transporters (ZnT1/ZnT2/ZnT5/ZIP4/DMT1) of young growing pigs. A total of 96 Duroc × Landrace × Yorkshire pigs were randomly allotted to two treatments and were fed a basal diet supplemented with 100 mg/kg Zn from either ZS or TBZ for 28 days. Feed : gain ratio in pigs fed TBZ were lower (P zinc transporter in either duodenum or jejunum of pigs fed TBZ were higher (P < 0.05) than pigs fed ZS. These results indicate that TBZ is more effective in serum Zn accumulation and intestinal Zn absorption, and might be a potential substitute for ZS in young growing pigs. © 2017 Japanese Society of Animal Science.

Availability of native and fertilizer zinc in some Indian soils: studies with 65Zinc

International Nuclear Information System (INIS)

Chaudhury, J.; Deb, D.L.

1979-01-01

Isotopically exchangeable zinc (Et values) was determined by different methods in some soils having pH(H 2 O) varying from 3.05 to 8.40 using 65 Zn. The Et values obtained using different extractants showed significant correlation with available zinc, organic carbon and soil pH. The recovery of applied zinc in the aqueous phase was less than one percent in most of the soils having pH higher than 7.0. Application of zinc with complexing agents like DTPA and EDTA increased the recovery of applied zinc in the solution to about 95 percent. Soil pH, organic C and DTPA extractable zinc showed significant relationship with the recovery of applied zinc under different treatments. Use of EDTA and DTPA extractants reduced the zinc buffering capacity of soil to a value less than one, irrespective of the initial pH of the soil, whereas the values were comparatively higher in presence of different levels of zinc carrier. (auth.)

65Zinc and endogenous zinc content and distribution in islets in relationship to insulin content

International Nuclear Information System (INIS)

Figlewicz, D.P.; Forhan, S.E.; Hodgson, A.T.; Grodsky, G.M.

1984-01-01

Uptake of 65 Zn and distribution of 65 Zn, total zinc, and insulin were measured in rat islets and islet granules under different conditions of islet culture. Specific activity of islet zinc ( 65 Zn/zinc) was less than 15% that of extracellular zinc even after 48 h. In contrast, once in the islet, 65 Zn approached 70% of equilibrium with granular zinc in 24 h and apparent equilibrium by 48 h. During a 24-h culture, at either high or low glucose, reduction of both islet zinc and insulin occurred. However, zinc depletion was greater than that predicted if zinc loss was proportional to insulin depletion and occurred only from the granular compartment, which represents only one third of the total islet zinc. Extension of culture to 48 h caused additional insulin depletion, but islet zinc was unchanged. Omission of calcium during the 48-h culture caused a predicted increase in insulin retention, presumably by inhibiting secretion; however, zinc retention was not increased proportionately. Pretreatment of rats with tolbutamide caused a massive depletion of insulin stored in isolated islets, with little change in total islet zinc; subsequent culture of these islets resulted in a greater loss of granular zinc than predicted from the small loss of granular insulin. None of the conditions tested affected the percentage of either 65 Zn or total zinc that was distributed in the islet granules. Results show that zinc exists in a metabolically labile islet compartment(s) as well as in secretory granules; and extra-granular zinc, although not directly associated with insulin storage, may act as a reservoir for granular zinc and may regulate insulin synthesis, storage, and secretion in ways as yet unknown

The Potential for Zinc Stable Isotope Techniques and Modelling to Determine Optimal Zinc Supplementation

Directory of Open Access Journals (Sweden)

Cuong D. Tran

2015-05-01

Full Text Available It is well recognised that zinc deficiency is a major global public health issue, particularly in young children in low-income countries with diarrhoea and environmental enteropathy. Zinc supplementation is regarded as a powerful tool to correct zinc deficiency as well as to treat a variety of physiologic and pathologic conditions. However, the dose and frequency of its use as well as the choice of zinc salt are not clearly defined regardless of whether it is used to treat a disease or correct a nutritional deficiency. We discuss the application of zinc stable isotope tracer techniques to assess zinc physiology, metabolism and homeostasis and how these can address knowledge gaps in zinc supplementation pharmacokinetics. This may help to resolve optimal dose, frequency, length of administration, timing of delivery to food intake and choice of zinc compound. It appears that long-term preventive supplementation can be administered much less frequently than daily but more research needs to be undertaken to better understand how best to intervene with zinc in children at risk of zinc deficiency. Stable isotope techniques, linked with saturation response and compartmental modelling, also have the potential to assist in the continued search for simple markers of zinc status in health, malnutrition and disease.

The Potential for Zinc Stable Isotope Techniques and Modelling to Determine Optimal Zinc Supplementation

Science.gov (United States)

Tran, Cuong D.; Gopalsamy, Geetha L.; Mortimer, Elissa K.; Young, Graeme P.

2015-01-01

It is well recognised that zinc deficiency is a major global public health issue, particularly in young children in low-income countries with diarrhoea and environmental enteropathy. Zinc supplementation is regarded as a powerful tool to correct zinc deficiency as well as to treat a variety of physiologic and pathologic conditions. However, the dose and frequency of its use as well as the choice of zinc salt are not clearly defined regardless of whether it is used to treat a disease or correct a nutritional deficiency. We discuss the application of zinc stable isotope tracer techniques to assess zinc physiology, metabolism and homeostasis and how these can address knowledge gaps in zinc supplementation pharmacokinetics. This may help to resolve optimal dose, frequency, length of administration, timing of delivery to food intake and choice of zinc compound. It appears that long-term preventive supplementation can be administered much less frequently than daily but more research needs to be undertaken to better understand how best to intervene with zinc in children at risk of zinc deficiency. Stable isotope techniques, linked with saturation response and compartmental modelling, also have the potential to assist in the continued search for simple markers of zinc status in health, malnutrition and disease. PMID:26035248

Effect of zinc from zinc sulfate on trace mineral concentrations of milk ...

African Journals Online (AJOL)

PRECIOUS

2009-11-16

Nov 16, 2009 ... It suggests that supplementation of ewes diet with zinc sulfate could be an effective way to increase zinc ... alkaline phosphates activity. Zinc supplements were .... Similar results have been reported previously when dairy cows.

Evolution of the zinc compound nanostructures in zinc acetate single-source solution

International Nuclear Information System (INIS)

Wang Ying; Li Yinhua; Zhou Zhengzhi; Zu Xihong; Deng Yulin

2011-01-01

A series of nanostructured zinc compounds with different nanostructures such as nanobelts, flake-like, flower-like, and twinning crystals was synthesized using zinc acetate (Zn(Ac) 2 ) as a single-source. The evolution of the zinc compounds from layered basic zinc acetate (LBZA) to bilayered basic zinc acetate (BLBZA) and twinned ZnO nano/microcrystal was studied. The low-angle X-ray diffraction spectra indicate the layered spacing is 1.34 and 2.1 nm for LBZA and BLBZA, respectively. The Fourier transform infrared (FTIR) spectra results confirmed that the bonding force of acetate anion with zinc cations decreases with the phase transformation from Zn(Ac) 2 to BLBZA, and finally to LBZA. The OH − groups gradually replaced the acetate groups coordinated to the matrix zinc cation, and the acetate groups were released completely. Finally, the Zn(OH) 2 and ZnO were formed at high temperature. The conversion process from Zn(Ac) 2 to ZnO with release of acetate anions can be described as Zn(Ac) 2 → BLBZA → LBZA → Zn(OH) 2 → ZnO.

Effects of dietary zinc status on seizure susceptibility and hippocampal zinc content in the El (epilepsy) mouse.

Science.gov (United States)

Fukahori, M; Itoh, M

1990-10-08

The effects of dietary zinc status on the development of convulsive seizures, and zinc concentrations in discrete hippocampal areas and other parts of the limbic system were studied in the El mouse model receiving zinc-adequate, zinc-deficient or zinc-loaded diets. Seizure susceptibility of the El mouse was increased by zinc deficiency, and decreased by zinc loading, while an adequate diet had no effect. Zinc loading was accompanied by a marked increase in hippocampal zinc content in the El mouse. Conversely, hippocampal zinc content declined in the El mouse fed a zinc-deficient diet. These results suggest that zinc may have a preventive effect on the development of seizures in the El mouse, and hippocampal zinc may play an important role in the pathophysiology of convulsive seizures of epilepsy.

Intestinal absorption and excretion of zinc in streptozotocin-diabetic rats as affected by dietary zinc and protein

International Nuclear Information System (INIS)

Johnson, W.T.; Canfield, W.K.

1985-01-01

65 Zn was used to examine the effects of dietary zinc and protein on true zinc absorption and intestinal excretion of endogenous zinc by an isotope dilution technique in streptozotocin-diabetic and control rats. Four groups each of diabetic and control rats were fed diets containing 20 ppm Zn, 20% egg white protein (HMHP); 20 ppm Zn, 10% egg white protein (HMLP); 10 ppm Zn, 20% egg white protein (LMHP); and 10 ppm Zn, 10% egg white protein (LMLP). Measurement of zinc balance was begun 9 d after an i.m. injection of 65 Zn. True zinc absorption and the contribution of endogenous zinc to fecal zinc excretion were calculated from the isotopically labeled and unlabeled zinc in the feces, duodenum and kidney. Results from the isotope dilution study indicated that diabetic rats, but not control rats, absorbed more zinc from 20 ppm zinc diets than from 10ppm zinc diets and that all rats absorbed more zinc from 20% protein diets than from 10% protein diets. Furthermore, all rats excreted more endogenous zinc from their intestines when dietary zinc and protein levels resulted in greater zinc absorption. In diabetic and control rats, consuming equivalent amounts of zinc, the amount of zinc absorbed was not significantly different, but the amount of zinc excreted by the intestine was less in the diabetic rats. Decreased intestinal excretion of endogenous zinc may be a homeostatic response to the increased urinary excretion of endogenous zinc in the diabetic rats and may also lead to the elevated zinc concentrations observed in some organs of the diabetic rats

Remodelamento metabólico de Paracoccidioides lutzii durante a privação de cobre determinado por análises proteômicas

OpenAIRE

Gonçalves, Laura Maria Barbosa

2015-01-01

Paracoccidioides spp. é um fungo termodimórfico, agente etiológico da paracoccidioidomicose (PCM). Durante o processo de infecção Paracoccidioides spp. encontra ambientes com diferentes disponibilidades de micronutrientes essenciais como cobre, por exemplo. A obtenção de micronutrientes no hospedeiro é mecanismo crucial de estratégia adaptativa deste patógeno. Neste sentido, a identificação de proteínas relacionadas com captação/homeostase de metais traços, durante a infecção é importante par...

Determinação de cobre, ferro, manganês e zinco, num mesmo extrato de planta, por potometria de chama de absorção The determination of copper, iron, manganese and zinc in a bulk plant extract by atomic absorption spectrophotometry

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J. Romano Gallo

1971-05-01

Full Text Available É apresentado um método de determinação, num mesmo extrato de planta, de ferro, manganês e zinco na fase aquosa, e de cobre, após sua extração em solvente orgânico. Para êsse estudo usou-se um analisador automático de absorção atômica Perkin-Elmer, modêlo 4A. Somente á silica, em certas concentrações, poderá constituir problema na determinação de manganês ou ferro, na ausência de cálcio. Na extração quantitativa do cobre é necessário conservar o pH abaixo de 2, para evitar interferência de ferro.A method was developed to determine quantitatively Cu, Fe, Mn and Zn in a bulk plant extract, using flame absorption photometry. The process measures Fe, Mn and Zn directly in the aqueous solution, but a concentration of the extract with organic solvents is required for copper determination. Essentially the process consists in obtaining the plant extract through digestion of 1.000 g of the ground dry samples, with HNO3 and later with HC10(4-H2S0(4 (7:1 v/v, then the solution is diluted to 50 ml with water. Thirty ml of this solution are transferred to a separatory funnel, where the copper is extracted by the ammonium pyrrolidine dithiocarbamate/ methyl isobutyl ketone system, and its amount determined. It is necessary to keep the pH below 2 to avoid interference of Fe on Cu determination. Mn, Fe and Zn are determined directly in the remaining 20 ml of plant extract. It has been noticed that silicon might cause some problems in the determination of Fe and Mn, in the absence of Ca. All the determinations were made in a Perkin-Elmer mod. 4A atomic absorption automatic analyser.

Chelators for investigating zinc metalloneurochemistry

OpenAIRE

Radford, Robert John; Lippard, Stephen J.

2013-01-01

The physiology and pathology of mobile zinc signaling has become an important topic in metalloneurochemistry. To study the action of mobile zinc effectively, specialized tools are required that probe the temporal and positional changes of zinc ions within live tissue and cells. In the present article we describe the design and implementation of selective zinc chelators as antagonists to interrogate the function of mobile zinc, with an emphasis on the pools of vesicular zinc in the terminals o...

Zinc and gastrointestinal disease

Institute of Scientific and Technical Information of China (English)

Sonja; Skrovanek; Katherine; DiGuilio; Robert; Bailey; William; Huntington; Ryan; Urbas; Barani; Mayilvaganan; Giancarlo; Mercogliano; James; M; Mullin

2014-01-01

This review is a current summary of the role that both zinc deficiency and zinc supplementation can play in the etiology and therapy of a wide range of gastrointestinal diseases. The recent literature describing zinc action on gastrointestinal epithelial tight junctions and epithelial barrier function is described. Zinc enhancement of gastrointestinal epithelial barrier function may figure prominently in its potential therapeutic action in several gastrointestinal diseases.

CONCENTRACIÓN MAGNÉTICA APLICADA A RELAVE DE COBRE

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Luis Valderrama Campusano

2015-02-01

Full Text Available Este trabajo tiene como objetivo desarrollar un circuito de concentración magnética de baja intensidad para tratar relave producido en el tratamiento de minerales de cobre. Para este estudio fueron recolectadas muestras de 27 calicatas construidas y distribuidas a lo largo de la corona del tranque de relaves de la Planta Manuel Antonio Matta de la Empresa Nacional de Minería. El análisis mineralógico indicó la presencia de cuarzo, ortoclasa, magnetita, actinolita, biotita y clinocloro ferroso, albita cálcica, calcita, hematita, pirita, pirrotina y calcopirita. El análisis químico mostró un contenido de hierro total de 18,5% y de hierro magnético de 15,2%. Pruebas realizadas en un Tubo Davis indican que se puede obtener un concentrado con ley de 66,4% de hierro, 3,9% SiO2, 0,70% Al2O3, 0,69% de MgO, 0,60% de CaO y 0,178 de azufre, siendo la recuperación de hierro del 79,2%. Se realizaron pruebas de concentración, a escala de laboratorio, en un separador magnético WLIMS. El concentrado rougher del separador magnético fue remolido hasta una granulometría cuyo P80 es de 50 mm, siguiendo luego  pruebas de limpieza, que entregaron un producto final con una ley de hierro de 63,1 %, hierro magnético 61,83 %, azufre 0,23%, SiO2  7%, Al2O3 1,16%, CaO 0,52% y MgO 0,52%.

Zinc species distribution in EDTA-extract residues of zinc-contaminated soil

International Nuclear Information System (INIS)

Chang, S.-H.; Wei, Y.-L.; Wang, H. Paul

2007-01-01

Soil sample from a site heavily contaminated with >10 wt.% zinc is sampled and extracted with aqueous solutions of ethylene diamine tetra-acetic acid (EDTA) that is a reagent frequently used to extract heavy metals in soil remediation. Three liquid/soil ratios (5/1, 20/1, and 100/1) were used in the extracting experiment. The molecular environment of the residual Zn in the EDTA-extract residues of zinc-contaminated soil is investigated with XANES technique. The results indicate that EDTA does not show considerable preference of chelating for any particular Zn species during the extraction. Zn species distribution in the sampled soil is found to resemble that in all EDTA-extract residues; Zn(OH) 2 is determined as the major zinc species (60-70%), seconded by organic zinc (21-26%) and zinc oxide (9-14%)

Innovative uses for zinc in dermatology.

Science.gov (United States)

Bae, Yoon Soo; Hill, Nikki D; Bibi, Yuval; Dreiher, Jacob; Cohen, Arnon D

2010-07-01

Severe zinc deficiency states, such as acrodermatitis enteropathica, are associated with a variety of skin manifestations, such as perioral, acral, and perineal dermatitis. These syndromes can be reversed with systemic zinc repletion. In addition to skin pathologies that are clearly zinc-dependent, many dermatologic conditions (eg, dandruff, acne, and diaper rash) have been associated and treated with zinc. Success rates for treatment with zinc vary greatly depending on the disease, mode of administration, and precise zinc preparation used. With the exception of systemic zinc deficiency states, there is little evidence that convincingly demonstrates the efficacy of zinc as a reliable first-line treatment for most dermatologic conditions. However, zinc may be considered as an adjunctive treatment modality. Further research is needed to establish the indications for zinc treatment in dermatology, optimal mode of zinc delivery, and best type of zinc compound to be used. Copyright 2010 Elsevier Inc. All rights reserved.

Cobre en alimentos de consumo básico por espectroscopia de absorción atómica modalidad de llama, Costa Rica

OpenAIRE

Paulina Silva Trejos

2012-01-01

Objetivo: Cuantificar el contenido de cobre en alimentos de la canasta básica de consumo del costarricense. Materiales y métodos: Los alimentos se procesaron de acuerdo con el patrón de consumo costarricense, se determinó la cantidad óptima de HNO3.al 65 % óptimo para su digestión en horno de microondas por evaluación de los porcentajes de recuperación. La cuantificación se realizó sobre las muestras digeridas por espectroscopia de absorción atómica de llama., las mediciones se hicieron a 324...

Effect of resveratrol and zinc on intracellular zinc status in normal human prostate epithelial cells

Science.gov (United States)

To evaluate the influence of resveratrol on cellular zinc status, normal human prostate epithelial (NHPrE) cells were treated with 6 levels of resveratrol (0, 0.5, 1, 2.5, 5 and 10 microM) and 4 levels of zinc [0, 4, 16, and 32 microM for zinc-deficient (ZD), zinc-normal (ZN), zinc-adequate (ZA), an...

Sulfidation of zinc plating sludge with Na2S for zinc resource recovery

International Nuclear Information System (INIS)

Kuchar, D.; Fukuta, T.; Onyango, M.S.; Matsuda, H.

2006-01-01

A high amount of zinc disposed in the landfill sites as a mixed-metal plating sludge represents a valuable zinc source. To recover zinc from the plating sludge, a sulfidation treatment is proposed in this study, while it is assumed that ZnS formed could be separated by flotation. The sulfidation treatment was conducted by contacting simulated zinc plating sludge with Na 2 S solution at S 2- to Zn 2+ molar ratio of 1.5 for a period of 1-48 h, while changing the solid to liquid (S:L) ratio from 0.25:50 to 1.00:50. The conversion of zinc compounds to ZnS was determined based on the consumption of sulfide ions. The reaction products formed by the sulfidation of zinc were identified by X-ray diffraction (XRD). As a result, it was found that the conversion of zinc compounds to ZnS increased with an increase in S:L ratio. A maximum conversion of 0.809 was obtained at an S:L ratio of 1.00:50 after 48 h. However, when the zinc sludge treated at S:L ratio of 1.00:50 for 48 h was subjected to XRD analyses, only ZnS was identified in the treated zinc sludge. The result suggested that the rest of zinc sludge remained unreacted inside the agglomerates of ZnS. The formation behavior of ZnS was predicted by Elovich equation, which was found to describe the system satisfactorily indicating the heterogeneous nature of the sludge

Interaction Between Yeasts and Zinc

Science.gov (United States)

Nicola, Raffaele De; Walker, Graeme

Zinc is an essential trace element in biological systems. For example, it acts as a cellular membrane stabiliser, plays a critical role in gene expression and genome modification and activates nearly 300 enzymes, including alcohol dehydrogenase. The present chapter will be focused on the influence of zinc on cell physiology of industrial yeast strains of Saccharomyces cerevisiae, with special regard to the uptake and subsequent utilisation of this metal. Zinc uptake by yeast is metabolism-dependent, with most of the available zinc translocated very quickly into the vacuole. At cell division, zinc is distributed from mother to daughter cells and this effectively lowers the individual cellular zinc concentration, which may become zinc depleted at the onset of the fermentation. Zinc influences yeast fermentative performance and examples will be provided relating to brewing and wine fermentations. Industrial yeasts are subjected to several stresses that may impair fermentation performance. Such stresses may also impact on yeast cell zinc homeostasis. This chapter will discuss the practical implications for the correct management of zinc bioavailability for yeast-based biotechnologies aimed at improving yeast growth, viability, fermentation performance and resistance to environmental stresses

Iron and zinc concentrations and 59Fe retention in developing fetuses of zinc-deficient rats

International Nuclear Information System (INIS)

Rogers, J.M.; Loennerdal, B.H.; Hurley, L.S.; Keen, C.L.

1987-01-01

Because disturbances in iron metabolism might contribute to the teratogenicity of zinc deficiency, we examined the effect of zinc deficiency on fetal iron accumulation and maternal and fetal retention of 59 Fe. Pregnant rats were fed from mating a purified diet containing 0.5, 4.5 or 100 micrograms Zn/g. Laparotomies were performed on d 12, 16, 19 and 21 of gestation. Maternal blood and concepti were analyzed for zinc and iron. Additional groups of dams fed 0.5 or 100 micrograms Zn/g diet were gavaged on d 19 with a diet containing 59 Fe. Six hours later maternal blood and tissues, fetuses and placentas were counted for 59 Fe. Maternal plasma zinc, but not iron, concentration was affected by zinc deficiency on d 12. Embryo zinc concentration on d 12 increased with increasing maternal dietary zinc, whereas iron concentration was not different among groups. On d 16-21 plasma iron was higher in dams fed 0.5 micrograms Zn/g diet than in those fed 4.5 or 100 micrograms/g, whereas plasma zinc was lower in dams fed 0.5 or 4.5 micrograms Zn/g than in those fed 100 micrograms Zn/g diet. On d 19 zinc concentration in fetuses from dams fed 0.5 micrograms/g zinc was not different from that of those fed 4.5 micrograms/g zinc, and iron concentration was higher in the 0.5 microgram Zn/g diet group. The increase in iron concentration in zinc-deficient fetuses thus occurs too late to be involved in major structural teratogenesis. Although whole blood concentration of 59 Fe was not different in zinc-deficient and control dams, zinc-deficient dams had more 59 Fe in the plasma fraction

Chloroquine is a zinc ionophore.

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Jing Xue

Full Text Available Chloroquine is an established antimalarial agent that has been recently tested in clinical trials for its anticancer activity. The favorable effect of chloroquine appears to be due to its ability to sensitize cancerous cells to chemotherapy, radiation therapy, and induce apoptosis. The present study investigated the interaction of zinc ions with chloroquine in a human ovarian cancer cell line (A2780. Chloroquine enhanced zinc uptake by A2780 cells in a concentration-dependent manner, as assayed using a fluorescent zinc probe. This enhancement was attenuated by TPEN, a high affinity metal-binding compound, indicating the specificity of the zinc uptake. Furthermore, addition of copper or iron ions had no effect on chloroquine-induced zinc uptake. Fluorescent microscopic examination of intracellular zinc distribution demonstrated that free zinc ions are more concentrated in the lysosomes after addition of chloroquine, which is consistent with previous reports showing that chloroquine inhibits lysosome function. The combination of chloroquine with zinc enhanced chloroquine's cytotoxicity and induced apoptosis in A2780 cells. Thus chloroquine is a zinc ionophore, a property that may contribute to chloroquine's anticancer activity.

[Advances in the research of zinc deficiency and zinc supplementation treatment in patients with severe burns].

Science.gov (United States)

Wang, X X; Zhang, M J; Li, X B

2018-01-20

Zinc is one of the essential trace elements in human body, which plays an important role in regulating acute inflammatory response, glucose metabolism, anti-oxidation, immune and gastrointestinal function of patients with severe burns. Patients with severe burns may suffer from zinc deficiency because of insufficient amount of zinc intake from the diet and a large amount of zinc lose through wounds and urine. Zinc deficiency may affect their wound healing process and prognosis. This article reviews the characteristics of zinc metabolism in patients with severe burns through dynamic monitoring the plasma and urinary concentration of zinc. An adequate dosage of zinc supplemented to patients with severe burns by an appropriate method can increase the level of zinc in plasma and skin tissue and improve wound healing, as well as reduce the infection rates and mortality. At the same time, it is important to observe the symptoms and signs of nausea, dizziness, leukopenia and arrhythmia in patients with severe burns after supplementing excessive zinc.

Reproducción de Eisenia foetida en suelos agrícolas de áreas mineras contaminadas por cobre y arsénico Reproduction of Eisenia foetida in agricultural soils from mining areas contaminated with copper and arsenic

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Gonzalo Ávila

2007-03-01

Full Text Available El objetivo del trabajo fue evaluar la toxicidad del cobre y arsénico en suelos agrícolas, mediante bioensayos estandarizados de toxicidad aguda y crónica sobre Eisenia foetida y relacionar la respuesta de ésta con las concentraciones de cobre y arsénico en los suelos. Los suelos agrícolas fueram muestreados en las inmediaciones de áreas mineras en la cuenca del río Aconcagua, Chile. E. foetida expuesta a los suelos estudiados mostró una baja mortalidad, indicando la ausencia de toxicidad aguda. Además, se observó una disminución en la producción de capullos y desarrollo de juveniles, indicando la existencia de toxicidad crónica. Dicha disminución fue relacionada con las concentraciones de cobre y arsénico en los suelos. El cobre y arsénico en conjunto disminuyeron la producción de capullos, mientras que sólo el arsénico disminuyó el desarrollo de juveniles. Suelos agrícolas provenientes de áreas mineras de la cuenca poseen potenciales características tóxicas para el desarrollo de la macrofauna edáfica.The objective of this work was to evaluate copper and arsenic toxicity in agricultural soils, by means of standardized bioassays of chronic and acute toxicity on Eisenia foetida, and to relate E. foetida response to copper and arsenic concentrations in soils. The agricultural soils were sampled in the proximity of copper mining industries, in the Aconcagua river basin, Chile. E. foetida exposed to the studied soils exhibited a low mortality, indicating the absence of acute toxicity. Besides, a decrease in the cocoon production and juvenile development was observed, indicating the existence of chronic toxicity. Reduction in the cocoon production and juvenile development was related to soil concentrations of copper and arsenic. Both copper and arsenic reduced the cocoon production, while only arsenic diminished the juvenile development. Agricultural soils from mining areas of the basin have potentially toxic characteristics

Posibilidades sobre el uso de residuos de la industria del acero en la eliminación de metales de efluentes líquidos

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Martín, M. I.

2004-10-01

Full Text Available A study is made of the removal of metals present in aqueous effluents using a residue of the steelmaking industry denominated rolling mill scale. Mill scale can be considered a cheap material for the removal of toxic metals due to its high content in iron oxides and metallic iron. A study of the removal of Cd₊₂, Zn₊₂, Pb₊₂ y Cu₊₂ ions from aqueous solutions was made, studying several variables that affect the process. The removal of cadmium, zinc and lead corresponding to a superficial adsorption process, was evaluated using the theories of Langmuir and Freundlich. The removal of copper occurs through a process of oxidation-reduction or cementation (Cu₊₂/Fe₀. The possibilities of desorption were studied too.

Se estudia la eliminación de metales presentes en efluentes acuosos empleando un residuo de la industria del acero denominado cascarilla de laminación. La cascarilla se puede considerar como un material barato para la eliminación de metales tóxicos por su alto contenido en óxidos de hierro y hierro metálico. Se ha realizado un estudio de la eliminación de los iones Cd₊₂, Zn₊₂, Pb₊₂ y Cu₊₂ contenidos en soluciones acuosas, estudiándose diversas variables que afectan al proceso. La eliminación de cadmio, cinc y plomo correspondiente a un proceso de adsorción superficial, se ha evaluado aplicando las teorías de Langmuir y Freundlich. La eliminación de cobre ocurre por un proceso de oxidación-reducción o cementación (Cu₊₂/Fe₀. Se han ensayado, también, las posibilidades de desorción.

Floating macrophytes on the wastewater treatment: a state of the art review Macrófitas flotantes en el tratamiento de aguas residuales: una revisión del estado del arte

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Jorge Martelo

2012-06-01

Full Text Available The wastewater treatments with floating macrophytes have proven effective in the remediation of waters with nutrient content, organic matter and toxic substances such as arsenic, zinc, cadmium, copper, lead, chromium, and mercury. Its importance lies in its ability to be used in rural communities due to their low consumption of conventional energy and practicality in the assembly and operation of treatment systems. Still, it has not been clarified thoroughly the processes taking place in the purification of wastewater with floating macrophytes. This article attempts to review the existing literature on floating macrophytes, thus identifying the general aspects, advantages and disadvantages of using these plants for treating wastewater. Similarly, identify the most important background since the beginning of this application. There will be described models and design criteria mostly employed, rigorously reviewing removal efficiencies of different species of floating macrophytes. Finally it will be addressed as discussed current perspectives and future challenges for the development of this technique.Los tratamientos de aguas residuales que involucran macrófitas flotantes han demostrado ser eficientes en la remediación de aguas con contenidos de nutrientes, materia orgánica y sustancias toxicas como arsénico, zinc, cadmio, cobre, plomo, cromo, y mercurio. Su importancia radica en su aptitud para ser empleados en núcleos rurales debido a su bajo consumo de energía convencional y la practicidad en el montaje y operación de los sistemas de tratamiento. Aun así, todavía no se han esclarecido rigurosamente los procesos que tienen lugar en la depuración de aguas residuales con macrófitas flotantes. El presente artículo pretende hacer un recorrido por la literatura existente sobre macrófitas flotantes, identificando los aspectos generales, ventajas y desventajas del uso de estas plantas para depurar aguas residuales. De igual manera

Zinc bioavailability in the chick

International Nuclear Information System (INIS)

Hempe, J.M.

1987-01-01

Methods for assessing zinc bioavailability were evaluated in the chick. A low-zinc chick diet was developed using rehydrated, spray-dried egg white autoclaved at 121 C for 30 min as the primary protein source. The relative bioavailability of zinc from soy flour and beef was determined by whole-body retention of extrinsic 65 Zn, and in slope ratio assays for growth rate and tissue zinc. Compared to zinc carbonate added to an egg white-based diet, all methods gave similar estimates of approximately 100% zinc bioavailability for beef but estimates for soy flour varied widely. The slope ratio assay for growth rate gave the best estimate of zinc bioavailability for soy flour. True absorption, as measured by percent isotope retention from extrinsically labeled soy flour, was 47%

Zinc and zinc transporters in macrophages and their roles in efferocytosis in COPD.

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Rhys Hamon

Full Text Available Our previous studies have shown that nutritional zinc restriction exacerbates airway inflammation accompanied by an increase in caspase-3 activation and an accumulation of apoptotic epithelial cells in the bronchioles of the mice. Normally, apoptotic cells are rapidly cleared by macrophage efferocytosis, limiting any secondary necrosis and inflammation. We therefore hypothesized that zinc deficiency is not only pro-apoptotic but also impairs macrophage efferocytosis. Impaired efferocytic clearance of apoptotic epithelial cells by alveolar macrophages occurs in chronic obstructive pulmonary disease (COPD, cigarette-smoking and other lung inflammatory diseases. We now show that zinc is a factor in impaired macrophage efferocytosis in COPD. Concentrations of zinc were significantly reduced in the supernatant of bronchoalveolar lavage fluid of patients with COPD who were current smokers, compared to healthy controls, smokers or COPD patients not actively smoking. Lavage zinc was positively correlated with AM efferocytosis and there was decreased efferocytosis in macrophages depleted of Zn in vitro by treatment with the membrane-permeable zinc chelator TPEN. Organ and cell Zn homeostasis are mediated by two families of membrane ZIP and ZnT proteins. Macrophages of mice null for ZIP1 had significantly lower intracellular zinc and efferocytosis capability, suggesting ZIP1 may play an important role. We investigated further using the human THP-1 derived macrophage cell line, with and without zinc chelation by TPEN to mimic zinc deficiency. There was no change in ZIP1 mRNA levels by TPEN but a significant 3-fold increase in expression of another influx transporter ZIP2, consistent with a role for ZIP2 in maintaining macrophage Zn levels. Both ZIP1 and ZIP2 proteins were localized to the plasma membrane and cytoplasm in normal human lung alveolar macrophages. We propose that zinc homeostasis in macrophages involves the coordinated action of ZIP1 and ZIP2

Bioavailability of Zinc in Wistar Rats Fed with Rice Fortified with Zinc Oxide

Science.gov (United States)

Della Lucia, Ceres Mattos; Santos, Laura Luiza Menezes; Rodrigues, Kellen Cristina da Cruz; Rodrigues, Vivian Cristina da Cruz; Martino, Hércia Stampini Duarte; Pinheiro Sant’Ana, Helena Maria

2014-01-01

The study of zinc bioavailability in foods is important because this mineral intake does not meet the recommended doses for some population groups. Also, the presence of dietary factors that reduce zinc absorption contributes to its deficiency. Rice fortified with micronutrients (Ultra Rice®) is a viable alternative for fortification since this cereal is already inserted into the population habit. The aim of this study was to evaluate the bioavailability of zinc (Zn) in rice fortified with zinc oxide. During 42 days, rats were divided into four groups and fed with diets containing two different sources of Zn (test diet: UR® fortified with zinc oxide, or control diet: zinc carbonate (ZnCO3)), supplying 50% or 100%, respectively, of the recommendations of this mineral for animals. Weight gain, food intake, feed efficiency ratio, weight, thickness and length of femur; retention of zinc, calcium (Ca) and magnesium (Mg) in the femur and the concentrations of Zn in femur, plasma and erythrocytes were evaluated. Control diet showed higher weight gain, feed efficiency ratio, retention of Zn and Zn concentration in the femur (p 0.05) for dietary intake, length and thickness of the femur, erythrocyte and plasmatic Zn between groups. Although rice fortified with zinc oxide showed a lower bioavailability compared to ZnCO3, this food can be a viable alternative to be used as a vehicle for fortification. PMID:24932657

Associations between Dietary Iron and Zinc Intakes, and between Biochemical Iron and Zinc Status in Women

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Karen Lim

2015-04-01

Full Text Available Iron and zinc are found in similar foods and absorption of both may be affected by food compounds, thus biochemical iron and zinc status may be related. This cross-sectional study aimed to: (1 describe dietary intakes and biochemical status of iron and zinc; (2 investigate associations between dietary iron and zinc intakes; and (3 investigate associations between biochemical iron and zinc status in a sample of premenopausal women aged 18–50 years who were recruited in Melbourne and Sydney, Australia. Usual dietary intakes were assessed using a 154-item food frequency questionnaire (n = 379. Iron status was assessed using serum ferritin and hemoglobin, zinc status using serum zinc (standardized to 08:00 collection, and presence of infection/inflammation using C-reactive protein (n = 326. Associations were explored using multiple regression and logistic regression. Mean (SD iron and zinc intakes were 10.5 (3.5 mg/day and 9.3 (3.8 mg/day, respectively. Median (interquartile range serum ferritin was 22 (12–38 μg/L and mean serum zinc concentrations (SD were 12.6 (1.7 μmol/L in fasting samples and 11.8 (2.0 μmol/L in nonfasting samples. For each 1 mg/day increase in dietary iron intake, zinc intake increased by 0.4 mg/day. Each 1 μmol/L increase in serum zinc corresponded to a 6% increase in serum ferritin, however women with low serum zinc concentration (AM fasting < 10.7 μmol/L; AM nonfasting < 10.1 μmol/L were not at increased risk of depleted iron stores (serum ferritin <15 μg/L; p = 0.340. Positive associations were observed between dietary iron and zinc intakes, and between iron and zinc status, however interpreting serum ferritin concentrations was not a useful proxy for estimating the likelihood of low serum zinc concentrations and women with depleted iron stores were not at increased risk of impaired zinc status in this cohort.

Effects of zinc supplementation and zinc chelation on in vitro β-cell function in INS-1E cells

DEFF Research Database (Denmark)

Nygaard, Sanne Bjørn; Larsen, Agnete; Knuhtsen, Astrid

2014-01-01

BACKGROUND: Zinc is essential for the activities of pancreatic β-cells, especially insulin storage and secretion. Insulin secretion leads to co-release of zinc which contributes to the paracrine communication in the pancreatic islets. Zinc-transporting proteins (zinc-regulated transporter, iron......-regulated transporter-like proteins [ZIPs] and zinc transporters [ZnTs]) and metal-buffering proteins (metallothioneins, MTs) tightly regulate intracellular zinc homeostasis. The present study investigated how modulation of cellular zinc availability affects β-cell function using INS-1E cells. RESULTS: Using INS-1E...... cells, we found that zinc supplementation and zinc chelation had significant effects on insulin content and insulin secretion. Supplemental zinc within the physiological concentration range induced insulin secretion. Insulin content was reduced by zinc chelation with N,N,N',N-tektrakis(2-pyridylmethyl...

Nutritional assessment methods for zinc supplementation in prepubertal non-zinc-deficient children

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Márcia Marília Gomes Dantas Lopes

2015-10-01

Full Text Available Background: Zinc is an essential nutrient that is required for numerous metabolic functions, and zinc deficiency results in growth retardation, cell-mediated immune dysfunction, and cognitive impairment. Objective: This study evaluated nutritional assessment methods for zinc supplementation in prepubertal non-zinc-deficient children. Design: We performed a randomised, controlled, triple-blind study. The children were divided into a control group (10% sorbitol, n=31 and an experimental group (10 mg Zn/day, n=31 for 3 months. Anthropometric and dietary assessments as well as bioelectrical measurements were performed in all children. Results: Our study showed (1 an increased body mass index for age and an increased phase angle in the experimental group; (2 a positive correlation between nutritional assessment parameters in both groups; (3 increased soft tissue, and mainly fat-free mass, in the body composition of the experimental group, as determined using bioelectrical impedance vector analysis; (4 increased consumption of all nutrients, including zinc, in the experimental group; and (5 an increased serum zinc concentration in both groups (p<0.0001. Conclusions: Given that a reference for body composition analysis does not exist for intervention studies, longitudinal studies are needed to investigate vector migration during zinc supplementation. These results reinforce the importance of employing multiple techniques to assess the nutritional status of populations.

Leptin, NPY, Melatonin and Zinc Levels in Experimental Hypothyroidism and Hyperthyroidism: The Relation to Zinc.

Science.gov (United States)

Baltaci, Abdulkerim Kasım; Mogulkoc, Rasim

2017-06-01

Since zinc mediates the effects of many hormones or is found in the structure of numerous hormone receptors, zinc deficiency leads to various functional impairments in the hormone balance. And also thyroid hormones have important activity on metabolism and feeding. NPY and leptin are affective on food intake and regulation of appetite. The present study is conducted to determine how zinc supplementation and deficiency affect thyroid hormones (free and total T3 and T4), melatonin, leptin, and NPY levels in thyroid dysfunction in rats. The experiment groups in the study were formed as follows: Control (C); Hypothyroidism (PTU); Hypothyroidism+Zinc (PTU+Zn); Hypothyroidism+Zinc deficient; Hyperthyroidism (H); Hyperthyroidism+Zinc (H+Zn); and Hyperthyroidism+Zinc deficient. Thyroid hormone parameters (FT 3 , FT 4 , TT 3 , and TT 4 ) were found to be reduced in hypothyroidism groups and elevated in the hyperthyroidism groups. Melatonin values increased in hyperthyroidism and decreased in hypothyroidism. Leptin and NPY levels both increased in hypo- and hyperthyroidism. Zinc levels, on the other hand, decreased in hypothyroidism and increased in hyperthyroidism. Zinc supplementation, particularly when thyroid function is impaired, has been demonstrated to markedly prevent these changes.

Zinc as a Gatekeeper of Immune Function

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Inga Wessels

2017-11-01

Full Text Available After the discovery of zinc deficiency in the 1960s, it soon became clear that zinc is essential for the function of the immune system. Zinc ions are involved in regulating intracellular signaling pathways in innate and adaptive immune cells. Zinc homeostasis is largely controlled via the expression and action of zinc “importers” (ZIP 1–14, zinc “exporters” (ZnT 1–10, and zinc-binding proteins. Anti-inflammatory and anti-oxidant properties of zinc have long been documented, however, underlying mechanisms are still not entirely clear. Here, we report molecular mechanisms underlying the development of a pro-inflammatory phenotype during zinc deficiency. Furthermore, we describe links between altered zinc homeostasis and disease development. Consequently, the benefits of zinc supplementation for a malfunctioning immune system become clear. This article will focus on underlying mechanisms responsible for the regulation of cellular signaling by alterations in zinc homeostasis. Effects of fast zinc flux, intermediate “zinc waves”, and late homeostatic zinc signals will be discriminated. Description of zinc homeostasis-related effects on the activation of key signaling molecules, as well as on epigenetic modifications, are included to emphasize the role of zinc as a gatekeeper of immune function.

Uptake and partitioning of zinc in Lemnaceae.

Science.gov (United States)

Lahive, Elma; O'Callaghan, Michael J A; Jansen, Marcel A K; O'Halloran, John

2011-11-01

Macrophytes provide food and shelter for aquatic invertebrates and fish, while also acting as reservoirs for nutrients and trace elements. Zinc accumulation has been reported for various Lemnaceae species. However, comparative accumulation across species and the link between zinc accumulation and toxicity are poorly understood. Morphological distribution and cellular storage, in either bound or soluble form, are important for zinc tolerance. This study shows differences in the uptake and accumulation of zinc by three duckweed species. Landoltia punctata and Lemna minor generally accumulated more zinc than Lemna gibba. L. minor, but not L. gibba or L. punctata, accumulated greater concentrations of zinc in roots compared to fronds when exposed to high levels of zinc. The proportion of zinc stored in the bound form relative to the soluble-form was higher in L. minor. L. punctata accumulated greater concentrations of zinc in fronds compared to roots and increased the proportion of zinc it stored in the soluble form, when exposed to high zinc levels. L. gibba is the only species that significantly accumulated zinc at low concentrations, and was zinc-sensitive. Overall, internal zinc concentrations showed no consistent correlation with toxic effect. We conclude that relationships between zinc toxicity and uptake and accumulation are species specific reflecting, among others, zinc distribution and storage. Differences in zinc distribution and storage are also likely to have implications for zinc bioavailability and trophic mobility.

Adsorción de plomo y cadmio en sistema continuo de lecho fijo sobre residuos de cacao

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Jose Lara

2016-12-01

Full Text Available Se evaluó el desempeño de la cáscara de cacao como material residual adsorbente de metales pesados (Plomo y Cadmio en solución acuosa sintética, mediante un sistema continuo de lecho fijo. El trabajo experimental consistió en determinar el efecto de la altura del lecho en la remoción de estos contaminantes, manteniendo constantes parámetros como el pH, velocidad de flujo y concentración inicial de los metales. Las pruebas de adsorción presentaron una remoción de 91,32 y 87,80% respectivamente para Pb y Cd después de transcurridos 4,5 h La medición de las concentraciones en solución acuosa de los iones metálicos se hizo por adsorción atómica. Se evaluó el ajuste de los modelos matemáticos de Thomas, Dosis-Respuesta, Adams-Bohart y BDST (Bed-Depht Service Time analysis, para predecir el comportamiento dinámico de la columna y obtener los parámetros cinéticos correspondientes. Para los modelos de Thomas y de Dosis-Respuesta, se observó que los valores de la capacidad inicial de adsorción, q0, disminuyeron al aumentar la altura del lecho, esto pudo deberse a una transferencia de masa más lenta, concentración más baja y aumento dela capacidad de adsorción, mientras que los modelos de Adams-Bohart y BDST, la capacidad de adsorción volumétrica, N0, decrece al aumentar el bioadsorbente en la columna. Los resultados presentados en este estudio indican que los residuos de cacao pueden ser usados para la remoción de metales pesados presentes en aguas residuales satisfactoriamente.

Estructura y propiedades del material compuesto de base cobre reforzado con partículas intermetálicas de TiB2. // Structure and properties of copper base reinforced with intermetallic particles of TiB2 material.

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M. López J.

2002-09-01

Full Text Available Se estudió las propiedades mecánicas y eléctricas de la aleación compuesta de base cobre reforzada mediante la dispersiónde cerámicas intermetálicas TiB2. La mezcla mecánica cobre-cerámica, se obtuvo aleando cobre en polvo de tamaño 140mm con 1% y 2% de TiB2 en volumen, además de dispersante en un molino planetario de inoxidable martensítico de altaenergía, con moliendas de 12 y 36 horas en atmósfera de argón y razón de carga bolas/masa en polvo de 10:1. Laconsolidación del aleado en polvo se realizó en dos etapas. Primeramente, se compactó uniaxialmente a 650ºC y 90MPa depresión en atmósfera de argón durante 2 horas. Finalmente el compacto se laminó en caliente a 800ºC con un 20% dereducción de área.El objetivo del estudio, es investigar la evolución de las propiedades mecánicas y eléctricas asociadas a los cambiosmicroestructurales producidos por el proceso de compactación y laminación en caliente.Se constató que el proceso de laminación en caliente actúa como un tratamiento de precipitación de fases frágiles, quedisminuyen la dureza y la resistencia a la tracción sin aumentar la ductilidad de los compactos. Cuando la compactaciónuniaxial es uniforme, el laminado en caliente posterior puede obviarse, obteniendo aleaciones con mejores propiedadesmecánicas en desmedro de las eléctricas. La caracterización microestructural realizada con TEM y Microsonda electrónicaWDX, confirma que las cerámicas de TiB2 dispersadas son estables y no se descomponen en otros compuestosintermetálicos con el cobre en el rango de los 800ºC. Microanálisis con TEM muestran la precipitación de fases frágiles deltipo Sigma (s provenientes de la contaminación de los medios de molienda.Palabras claves: Aleación de cobre, propiedades mecánicas, microestructura, laminado en caliente.____________________________________________________________________AbstractIn this paper an analisys of mechanical and electric properties of

Zinc oxide overdose

Science.gov (United States)

Zinc oxide is an ingredient in many products. Some of these are certain creams and ointments used ... prevent or treat minor skin burns and irritation. Zinc oxide overdose occurs when someone eats one of ...

Corrosión en medio ácido cítrico de una aleacion metálica de cobre aplicada en la odontologia

OpenAIRE

Vaz, Luís Geraldo; Guastaldi, Antônio Carlos; Marques de Brito, Adriano

2007-01-01

RESUMEN El objetivo de este trabajo fue caracterizar y estudiar el efecto del tratamiento térmico hecho en una aleación metálica de cobre para el uso odontológico, con relación a su comportamiento frente a la corrosión, en un medio que simula la agresividad del ambiente bucal. La caracterización de la aleación fue hecha por medio de análisis de la composición química y microscopia óptica y los ensayos de corrosión comprendieran en la obtención de las curvas de polarización potenciostáticas en...

Effect of zinc gluconate, sage oil on inflammatory patterns and hyperglycemia in zinc deficient diabetic rats.

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Elseweidy, Mohamed M; Ali, Abdel-Moniem A; Elabidine, Nabila Zein; Mursey, Nada M

2017-11-01

The relationship between zinc homeostasis and pancreatic function had been established. In this study we aimed firstly to configure the inflammatory pattern and hyperglycemia in zinc deficient diabetic rats. Secondly to illustrate the effect of two selected agents namely Zinc gluconate and sage oil (Salvia Officinalis, family Lamiaceae). Rats were fed on Zinc deficient diet, deionized water for 28days along with Zinc level check up at intervals to achieve zinc deficient state then rats were rendered diabetic through receiving one dose of alloxan monohydrate (120mg/kg) body weight, classified later into 5 subgroups. Treatment with sage oil (0.042mg/kg IP) and Zinc gluconate orally (150mg/kg) body weight daily for 8 weeks significantly reduced serum glucose, C-reactive protein (CRP), Tumor necrosis factor alpha (TNF- α), interleukins-6 1 β, inflammatory8 (IFN ȣ), pancreatic 1L1-β along with an increase in serum Zinc and pancreatic Zinc transporter 8 (ZNT8). Histopathological results of pancreatic tissues showed a good correlation with the biochemical findings. Both sage oil and zinc gluconate induced an improvement in the glycemic and inflammatory states. This may be of value like the therapeutic agent for diabetes. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Impact of anode substrates on electrodeposited zinc over cycling in zinc-anode rechargeable alkaline batteries

International Nuclear Information System (INIS)

Wei, Xia; Desai, Divyaraj; Yadav, Gautam G.; Turney, Damon E.; Couzis, Alexander; Banerjee, Sanjoy

2016-01-01

Electrochemical behavior of Ag, Bi, Cu, Fe, Ni and Sn substrates on zinc deposition was evaluated over battery cycling by cyclic voltammetry and electrochemical impedance spectroscopy. The effect of Bi, Cu, Ni, and Sn substrates on zinc electrodeposition during battery cycling was investigated using scanning electron microscopy and X-ray diffraction. The corrosion behavior of each metal in 9 M KOH and the corrosion rates of zinc plated on each substrate were analyzed by Tafel extrapolation method from the potentiodynamic polarization curves and electrochemical impedance spectroscopy. Although the charge-transfer resistance (R_c_t) of zinc electrodeposition is lowest on Sn, Sn eventually corrodes on cycling in alkaline media. Use of Ni as a substrate causes zinc to deteriorate on account of rapid hydrogen evolution. Bi and Cu substrates are more suitable for use as current collectors in zinc-anode alkaline rechargeable batteries because of their low corrosion rate and compact zinc deposition over battery cycling.

Immersion autometallography: histochemical in situ capturing of zinc ions in catalytic zinc-sulfur nanocrystals.

Science.gov (United States)

Danscher, Gorm; Stoltenberg, Meredin; Bruhn, Mikkel; Søndergaard, Chris; Jensen, Dorete

2004-12-01

In the mid-1980s, two versions of Timm's original immersion sulfide silver method were published. The authors used immersion of tissue in a sulfide solution as opposed to Timm, who used immersion of tissue blocks in hydrogen sulfide-bubbled alcohol. The autometallography staining resulting from the "sulfide only immersion" was not particularly impressive, but the significance of this return to an old approach became obvious when Wenzel and co-workers presented their approach in connection with introduction by the Palmiter group of zinc transporter 3 (ZnT3). The Wenzel/Palmiter pictures are the first high-resolution, high-quality pictures taken from tissues in which free and loosely bound zinc ions have been captured in zinc-sulfur nanocrystals by immersion. The trick was to place formalin-fixed blocks of mouse brains in a solution containing 3% glutaraldehyde and 0.1% sodium sulfide, ingredients used for transcardial perfusion in the zinc-specific NeoTimm method. That the NeoTimm technique results in silver enhancement of zinc-sulfur nanocrystals has been proved by proton-induced X-ray multielement analyses (PIXE) and in vivo chelation with diethyldithiocarbamate (DEDTC). The aims of the present study were (a) to make the immersion-based capturing of zinc ions in zinc-sulfur nanocrystals work directly on sections and slices of fixed brain tissue, (b) to work out protocols that ensure zinc specificity and optimal quality of the staining, (c) to apply "immersion autometallography" (iZnSAMG) to other tissues that contain zinc-enriched (ZEN) cells, and (d) to make the immersion approach work on unfixed fresh tissue.

Quantitative mapping of zinc fluxes in the mammalian egg reveals the origin of fertilization-induced zinc sparks

Energy Technology Data Exchange (ETDEWEB)

Que, Emily L.; Bleher, Reiner; Duncan, Francesca E.; Kong, Betty Y.; Gleber, Sophie C.; Vogt, Stefan; Chen, Si; Garwin, Seth A.; Bayer, Amanda R.; Dravid, Vinayak P.; Woodruff, Teresa K.; O' Halloran, Thomas V.

2014-12-15

Fertilization of a mammalian egg initiates a series of 'zinc sparks' that are necessary to induce the egg-to-embryo transition. Despite the importance of these zinc-efflux events little is known about their origin. To understand the molecular mechanism of the zinc spark we combined four physical approaches that resolve zinc distributions in single cells: a chemical probe for dynamic live-cell fluorescence imaging and a combination of scanning transmission electron microscopy with energy-dispersive spectroscopy, X-ray fluorescence microscopy and three-dimensional elemental tomography for high-resolution elemental mapping. We show that the zinc spark arises from a system of thousands of zinc-loaded vesicles, each of which contains, on average, 10(6) zinc atoms. These vesicles undergo dynamic movement during oocyte maturation and exocytosis at the time of fertilization. The discovery of these vesicles and the demonstration that zinc sparks originate from them provides a quantitative framework for understanding how zinc fluxes regulate cellular processes

Tolerância ao cobre em ecótipos de Schinus lentiscifolius March (Anacardiaceae de áreas de mineração no Rio Grande do Sul, Brasil Copper tolerance in ecotypes of Schinus lentiscifolius March (Anacardiaceae in mining regions of Rio Grande do Sul

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Maria Luiza Porto

1989-12-01

Full Text Available Sementes de Schinus lentiscifolius March, provenientes de duas áreas de mineração do Rio Grande do Sul, foram submetidas a testes de exposição ao CuSO4, visando comprovar a tolerância ao cobre na germinação e no desenvolvimento de plántulas. Os testes demonstraram que os dois clones reagem diferentemente ao cobre, porém ambos apresentaram mecanismos de tolerância. Plántulas provenientes de sementes da área de maior concentração de cobre no solo (minas do Seival apresentam sintomas de toxidez mais tardios do que plántulas provenientes de sementes da área de menor concentração deste íon (mina Sanga Negra.Seeds from Schinus lentiscifolius March collected in two mining areas in the state of Rio Grande do Sul, Brazil, were submitted to CuSO4 exposure tests to confirm copper tolerance during germination .and plantule development. The results showed that the two distinct clones respond differently to copper, but both presented tolerance mechanisms. Plantules originated from seeds collected in the area with higher soil copper concentration (minas do Seival presented toxicity symptoms later as compared to those plantules originated from seeds collected in the area with lower CU² + concentration (mina Sanga Negra.

Clinical Aspects of Trace Elements: Zinc in Human Nutrition – Zinc Deficiency and Toxicity

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Michelle M Pluhator

1996-01-01

Full Text Available Available evidence suggests that trace elements, such as zinc, once thought to have no nutritional relevance, are possibly deficient in large sections of the human population. Conditioned deficiencies have been reported to result from malabsorption syndromes, acrodermatitis enteropathica, alcoholism, gastrointestinal disease, thermal injury, chronic diseases (eg, diabetes, sickle cell anemia, and in total parenteral nutrition therapy. Awareness that patients with these problems are at risk has led health professionals to focus increasingly on the importance of zinc therapy in the prevention and treatment of deficiency. More recently zinc toxicity and its role in human nutrition and well-being have come under investigation. Reports have focused on the role of zinc toxicity in causes of copper deficiency, changes in the immune system and alterations in blood lipids. As the numerous challenges presented by the study of zinc in human nutrition are met, more appropriate recommendations for dietary and therapeutic zinc intake are being made.

Zinc in Infection and Inflammation.

Science.gov (United States)

Gammoh, Nour Zahi; Rink, Lothar

2017-06-17

Micronutrient homeostasis is a key factor in maintaining a healthy immune system. Zinc is an essential micronutrient that is involved in the regulation of the innate and adaptive immune responses. The main cause of zinc deficiency is malnutrition. Zinc deficiency leads to cell-mediated immune dysfunctions among other manifestations. Consequently, such dysfunctions lead to a worse outcome in the response towards bacterial infection and sepsis. For instance, zinc is an essential component of the pathogen-eliminating signal transduction pathways leading to neutrophil extracellular traps (NET) formation, as well as inducing cell-mediated immunity over humoral immunity by regulating specific factors of differentiation. Additionally, zinc deficiency plays a role in inflammation, mainly elevating inflammatory response as well as damage to host tissue. Zinc is involved in the modulation of the proinflammatory response by targeting Nuclear Factor Kappa B (NF-κB), a transcription factor that is the master regulator of proinflammatory responses. It is also involved in controlling oxidative stress and regulating inflammatory cytokines. Zinc plays an intricate function during an immune response and its homeostasis is critical for sustaining proper immune function. This review will summarize the latest findings concerning the role of this micronutrient during the course of infections and inflammatory response and how the immune system modulates zinc depending on different stimuli.

Dinamic of the cadmium in soils cultivated with potatoes in Nariño, Colombia

OpenAIRE

Insuasty B, Liliana; Burbano O, Hernán; Menjivar F, Juan C

2008-01-01

Se evaluó la fijación y movilidad de cadmio en suelos dedicados al cultivo de papa en Túquerres, Pasto y Guachucal. Se tomaron muestras de suelos no disturbadas en cilindros de PVC, las cuales, luego de aplicaciones fraccionadas de cadmio con dosis de 0, 50,100 y 150 ppm, se incubaron a capacidad de campo durante cuatro meses. En estos suelos los contenidos de cadmio total e intercambiable no sobrepasaron los límites permisibles establecidos por Organización Mundial de la Salud-Organización d...

Determinação dos teores de cobre em diferentes extratos de hortaliças do tipo A e B Determination of copper in differents extracts in samples of A and B vegetables

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Édira Castello Branco de Andrade

2004-06-01

Full Text Available Amostras de hortaliças dos tipos A e B foram analisadas quanto ao teor total de cobre através de espectroscopia de absorção atômica em chama, e o método de extração seqüencial foi aplicado com os seguintes extratores: solução de CaCl(21,0M; solução de ácido acético 0,1M; solução de ácido acético 0,5M / acetato de amônio 5% [pH=5,0]; solução de NaOH 0,1M e solução de HCl 0,5M. Na análise da rejeição de resultados foi aplicado o teste de Grubbs e na comparação dos dados o teste t de Student foi utilizado. Em média 25,4% do teor total de cobre foram extraídos com solução de CaCl2 1,0M, sendo o máximo de 50,5% e o mínimo de 8,3%. Em média 14,8% do teor total de cobre, sendo que 32,6% e 6,4%, máximo e mínimo respectivamente, foram extraídos com solução de ácido acético 0,1M. Com relação ao uso de solução de ácido acético 0,5M / acetato de amônio 5% [pH=5,0], o mínimo extraído obteve valor de 6,2% e o máximo 27,6%, com média de 13,7%. O extrator de NaOH 0,1M foi o que teve menor extração, cerca de 10,5% e com extrator de HCl 0,5M a extração foi em média de 12,6%. A fração extraída de cobre nas amostras foi de no mínimo 34,5% e no máximo 100%. Observa-se que para a maioria das amostras, o cobre se encontra sob a forma de, no mínimo, 6 espécies químicas distintas.Total copper content analysed in samples of A and B vegetables through atomic flame absorption spectroscopy and sequential extraction were performed by using the following extractants: CaCl(21.0M solution; acetic acid 0.1M; acetic acic 0.5M / ammonium acetate 5% solution [pH = 5.0]; NaOH 0.1M solution and HCl 0.5M solution. For evaluation of the results Grubbs test and Student test were used. On average 25.4% of total copper were extracted in CaCl2 1.0M solution with a maximum extraction of 50.5% and a minimum of 8.3%. On average 14.8% of the total amount of copper, a maximum of 32.6% and a minimum of 64% were extracted in

Influence of usual zinc intake and zinc in a meal on 65Zn retention and turnover in the rat

International Nuclear Information System (INIS)

Hunt, J.R.; Johnson, P.E.; Swan, P.B.

1987-01-01

The influences of zinc in a meal and usual zinc intake on zinc retention and turnover were investigated in 7-wk-old male rats fed diets containing 12-151 mg Zn/kg for 3 wk before and after consuming a 65 Zn-labeled meal containing ZnCl 2 . Retention corrected to zero time and turnover rate were determined by whole-body counting. Percent zinc retention was inversely proportional to the natural logarithm of the meal zinc, between 0.09 and 26 mumol. In comparison to lower doses, higher doses resulted in lower percent retention but greater amounts of zinc retained. Although the latter relationship was slightly curvilinear, there was no indication of a limited capacity for zinc retention with high doses. However, doses above 4 mumol resulted in higher turnover rates in rats accustomed to lower zinc intakes. Percent retention and the reciprocal of the turnover rate were proportional to the reciprocal of the dietary zinc concentration. The greatest differences in retention and turnover occurred between 12 and 26 mg Zn/kg diet. The zinc dose in a meal and the usual dietary zinc separately influenced percent zinc retention. These factors also interacted, such that greater dose effects were observed at lower zinc intakes and greater dietary zinc effects were observed at lower doses

Interdependence of free zinc changes and protein complex assembly - insights into zinc signal regulation.

Science.gov (United States)

Kocyła, Anna; Adamczyk, Justyna; Krężel, Artur

2018-01-24

Cellular zinc (Zn(ii)) is bound with proteins that are part of the proteomes of all domains of life. It is mostly utilized as a catalytic or structural protein cofactor, which results in a vast number of binding architectures. The Zn(ii) ion is also important for the formation of transient protein complexes with a Zn(ii)-dependent quaternary structure that is formed upon cellular zinc signals. The mechanisms by which proteins associate with and dissociate from Zn(ii) and the connection with cellular Zn(ii) changes remain incompletely understood. In this study, we aimed to examine how zinc protein domains with various Zn(ii)-binding architectures are formed under free Zn(ii) concentration changes and how formation of the Zn(ii)-dependent assemblies is related to the protein concentration and reactivity. To accomplish these goals we chose four zinc domains with different Zn(ii)-to-protein binding stoichiometries: classical zinc finger (ZnP), LIM domain (Zn 2 P), zinc hook (ZnP 2 ) and zinc clasp (ZnP 1 P 2 ) folds. Our research demonstrated a lack of changes in the saturation level of intraprotein zinc binding sites, despite various peptide concentrations, while homo- and heterodimers indicated a concentration-dependent tendency. In other words, at a certain free Zn(ii) concentration, the fraction of a formed dimeric complex increases or decreases with subunit concentration changes. Secondly, even small or local changes in free Zn(ii) may significantly affect protein saturation depending on its architecture, function and subcellular concentration. In our paper, we indicate the importance of interdependence of free Zn(ii) availability and protein subunit concentrations for cellular zinc signal regulation.

Effects of Foliar Application of Nano Zinc Chelate and Zinc Sulfate on Zinc Content, Pigments and Photosynthetic Indices of Holy Basil (Ocimum sanctum(

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Zohreh Moghimi pour

2017-02-01

Full Text Available Introduction: Holy basil is a perennial plant belongs to Lamiaceae family. The plant is a perennial and thrives well in the hot and humid climate. Its aerial parts have been in use for food, pharmaceuticals, cosmetics and perfumery industries. Leaves contain 0.5-1.5% essential oil and main oil components are eugenol, methyl eugenol, carvacrol, methyl chavicol and1,8-cineole. A balanced fertilization program with macro and micronutrients is very important in producing high quality yield. Zinc is involved in IAA production, chlorophyll biosynthesis, carbon assimilation, saccharids accumulation, reactive oxygen radicals scavenging and finally carbon utilization in volatile oil biosynthesis. Material and methods: In order to evaluate the effect on zinc foliar application on zinc content of leaves, photosynthetic indices and pigments of holy basil, an experiment was carried out in 2013 at a research farm of Horticultural Science, Shahid Chamran University (31°20'N latitude and 48°40'E longitude and 22.5 m mean sea level, Ahvaz (Iran, a region characterized by semi-dry climate. The experiment was arranged based on Randomized Complete Block Design (RCBD with six treatments and three replications. The treatments were nano zinc chelate (0, 0.5, 1 and 1.5 g.l-1 and zinc sulfate (1 and 1.5 g.l-1 fertilizers. Land preparation includes disking and the formation of raising beds (15cm high and 45cm wide across the top using a press-pan-type bed shaper. Holy basil seeds were sown on two rows on each bed, with 15 cm in-row and 40 cm between-row spacing. The plants were irrigated weekly as needed. Foliar application of zinc fertilizers was done at six-eight leaf stage and were repeated with interval 15 days until full bloom stage. Zinc content, stomata conductance (gs, CO2 under stomata (Ci, transpiration rate (E, net photosynthesis (Pn, light use efficiency (LUE, water use efficiency (WUE and also chlorophyll a, chlorophyll b, chlorophyll a+b and carotenoid

Deficiencia de zinc y sus implicaciones funcionales Zinc deficiency and its functional implications

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JORGE L ROSADO

1998-03-01

Full Text Available El presente trabajo tiene por objeto revisar los aspectos teóricos y los estudios realizados en México que sugieren la existencia de la deficiencia moderada de zinc en niños de población rural, así como algunas de las consecuencias de dicha deficiencia en la salud. El zinc es un nutrimento indispensable para el organismo de los humanos y juega un papel importante en una serie de procesos metabólicos: participa en el sitio catalítico de varios sistemas enzimáticos; participa como ion estructural en membranas biológicas, y guarda una estrecha relación con la síntesis de proteínas, entre otras cosas. Es por esto que la deficiencia de zinc está asociada con consecuencias importantes en la salud y la funcionalidad de los individuos, especialmente durante las primeras etapas de la vida. De relevancia para México es la existencia de una deficiencia moderada de zinc en los niños y las consecuencias que ésta pueda tener en la salud de los mismos. Los estudios realizados sugieren que la deficiencia moderada de zinc se presenta asociada con la ingestión de dietas basadas en alimentos de origen vegetal, las cuales contienen cantidades importantes de inhibidores de la absorción de zinc. Este tipo de dietas se consume habitualmente en las zonas rurales y en la población marginal de las ciudades en el país. Entre las consecuencias más importantes de esta deficiencia se encontró un aumento en la presencia de enfermedades infecciosas, especialmente de diarrea, y posibles alteraciones en el desarrollo de la capacidad cognoscitiva.The purpose of this article is to review theoretical aspects and research performed in Mexico suggesting the existence of marginal zinc deficiency in rural children and its consequences on health. Zinc is an indispensable nutrient for humans since it plays an important role in several metabolic pathways: it participates in the catalytic site of several enzymes, as a structural ion of biological membranes and is

Zinc in Infection and Inflammation

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Nour Zahi Gammoh

2017-06-01

Full Text Available Micronutrient homeostasis is a key factor in maintaining a healthy immune system. Zinc is an essential micronutrient that is involved in the regulation of the innate and adaptive immune responses. The main cause of zinc deficiency is malnutrition. Zinc deficiency leads to cell-mediated immune dysfunctions among other manifestations. Consequently, such dysfunctions lead to a worse outcome in the response towards bacterial infection and sepsis. For instance, zinc is an essential component of the pathogen-eliminating signal transduction pathways leading to neutrophil extracellular traps (NET formation, as well as inducing cell-mediated immunity over humoral immunity by regulating specific factors of differentiation. Additionally, zinc deficiency plays a role in inflammation, mainly elevating inflammatory response as well as damage to host tissue. Zinc is involved in the modulation of the proinflammatory response by targeting Nuclear Factor Kappa B (NF-κB, a transcription factor that is the master regulator of proinflammatory responses. It is also involved in controlling oxidative stress and regulating inflammatory cytokines. Zinc plays an intricate function during an immune response and its homeostasis is critical for sustaining proper immune function. This review will summarize the latest findings concerning the role of this micronutrient during the course of infections and inflammatory response and how the immune system modulates zinc depending on different stimuli.

Repletion of zinc in zinc-deficient cells strongly up-regulates IL-1β-induced IL-2 production in T-cells.

Science.gov (United States)

Daaboul, Doha; Rosenkranz, Eva; Uciechowski, Peter; Rink, Lothar

2012-10-01

Mild zinc deficiency in humans negatively affects IL-2 production resulting in declined percentages of cytolytic T cells and decreased NK cell lytic activity, which enhances the susceptibility to infections and malignancies. T-cell activation is critically regulated by zinc and the normal physiological zinc level in T-cells slightly lies below the optimal concentration for T-cell functions. A further reduction in zinc level leads to T-cell dysfunction and autoreactivity, whereas high zinc concentrations (100 μM) were shown to inhibit interleukin-1 (IL-1)-induced IL-1 receptor kinase (IRAK) activation. In this study, we investigated the molecular mechanism by which zinc regulates the IL-1β-induced IL-2 expression in T-cells. Zinc supplementation to zinc-deficient T-cells increased intracellular zinc levels by altering the expression of zinc transporters, particularly Zip10 and Zip12. A zinc signal was observed in the murine T-cell line EL-4 6.1 after 1 h of stimulation with IL-1β, measured by specific zinc sensors FluoZin-3 and ZinPyr-1. This signal is required for the phosphorylation of MAPK p38 and NF-κB subunit p65, which triggers the transcription of IL-2 and strongly increases its production. These results indicate that short-term zinc supplementation to zinc-deficient T-cells leads to a fast rise in zinc levels which subsequently enhance cytokine production. In conclusion, low and excessive zinc levels might be equally problematic for zinc-deficient subjects, and stabilized zinc levels seem to be essential to avoid negative concentration-dependent zinc effects on T-cell activation.

The study and microstructure analysis of zinc and zinc oxide

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N. Luptáková

2015-01-01

Full Text Available The given paper is closely connected with the process of the manufacturing of ZnO. The purity of the metal zinc has crucial influence on the quality of ZnO. ZnO can be produced by pyrometallurgical combustion of zinc and hard zinc. But this mentioned method of preparation leads to the creation of the enormous amount of waste including chemical complexes. On the basis of the occurrence of the residual content of other elements, it is possible to make prediction about the material behavior in the metallographic process. The input and finally materials were investigated and this investigation was done from the aspect of structural and chemical composition of the materials.

Cathodic hydrogen charging of zinc

International Nuclear Information System (INIS)

Panagopoulos, C.N.; Georgiou, E.P.; Chaliampalias, D.

2014-01-01

Highlights: •Incorporation of hydrogen into zinc and formation of zinc hydrides. •Investigation of surface residual stresses due to hydrogen diffusion. •Effect of hydrogen diffusion and hydride formation on mechanical properties of Zn. •Hydrogen embrittlement phenomena in zinc. -- Abstract: The effect of cathodic hydrogen charging on the structural and mechanical characteristics of zinc was investigated. Hardening of the surface layers of zinc, due to hydrogen incorporation and possible formation of ZnH 2 , was observed. In addition, the residual stresses brought about by the incorporation of hydrogen atoms into the metallic matrix, were calculated by analyzing the obtained X-ray diffraction patterns. Tensile testing of the as-received and hydrogen charged specimens revealed that the ductility of zinc decreased significantly with increasing hydrogen charging time, for a constant value of charging current density, and with increasing charging current density, for a constant value of charging time. However, the ultimate tensile strength of this material was slightly affected by the hydrogen charging procedure. The cathodically charged zinc exhibited brittle transgranular fracture at the surface layers and ductile intergranular fracture at the deeper layers of the material

A concentrated electrolyte for zinc hexacyanoferrate electrodes in aqueous rechargeable zinc-ion batteries

Science.gov (United States)

Kim, D.; Lee, C.; Jeong, S.

2018-01-01

In this study, a concentrated electrolyte was applied in an aqueous rechargeable zinc-ion battery system with a zinc hexacyanoferrate (ZnHCF) electrode to improve the electrochemical performance by changing the hydration number of the zinc ions. To optimize the active material, ZnHCF was synthesized using aqueous solutions of zinc nitrate with three different concentrations. The synthesized materials exhibited some differences in structure, crystallinity, and particle size, as observed by X-ray diffraction and scanning electron microscopy. Subsequently, these well-structured materials were applied in electrochemical tests. A more than two-fold improvement in the charge/discharge capacities was observed when the concentrated electrolyte was used instead of the dilute electrolyte. Additionally, the cycling performance observed in the concentrated electrolyte was superior to that in the dilute electrolyte. This improvement in the electrochemical performance may result from a decrease in the hydration number of the zinc ions in the concentrated electrolyte.

Zinc-mediated Allosteric Inhibition of Caspase-6*

Science.gov (United States)

Velázquez-Delgado, Elih M.; Hardy, Jeanne A.

2012-01-01

Zinc and caspase-6 have independently been implicated in several neurodegenerative disorders. Depletion of zinc intracellularly leads to apoptosis by an unknown mechanism. Zinc inhibits cysteine proteases, including the apoptotic caspases, leading to the hypothesis that zinc-mediated inhibition of caspase-6 might contribute to its regulation in a neurodegenerative context. Using inductively coupled plasma optical emission spectroscopy, we observed that caspase-6 binds one zinc per monomer, under the same conditions where the zinc leads to complete loss of enzymatic activity. To understand the molecular details of zinc binding and inhibition, we performed an anomalous diffraction experiment above the zinc edge. The anomalous difference maps showed strong 5σ peaks, indicating the presence of one zinc/monomer bound at an exosite distal from the active site. Zinc was not observed bound to the active site. The zinc in the exosite was liganded by Lys-36, Glu-244, and His-287 with a water molecule serving as the fourth ligand, forming a distorted tetrahedral ligation sphere. This exosite appears to be unique to caspase-6, as the residues involved in zinc binding were not conserved across the caspase family. Our data suggest that binding of zinc at the exosite is the primary route of inhibition, potentially locking caspase-6 into the inactive helical conformation. PMID:22891250

Environmental risk limits for zinc

NARCIS (Netherlands)

Bodar CWM; SEC

2007-01-01

Environmental Riks Limits (ERLs) were derived for zinc. ERLs serve as advisory values to set environmental quality standards in the Netherlands. The ERLs for zinc closely follow the outcomes of earlier discussions on zinc within the Water Framework Directive and EC Regulation 793/93. The ERLs

Environmental risk limits for zinc

NARCIS (Netherlands)

Bodar CWM; SEC

2007-01-01

Environmental Riks Limits (ERLs) were derived for zinc. ERLs serve as advisory values to set environmental quality standards in the Netherlands. The ERLs for zinc closely follow the outcomes of earlier discussions on zinc within the Water Framework Directive and EC Regulation 793/93. The ERLs refer

Zinc-The key to preventing corrosion

Science.gov (United States)

Kropschot, S.J.; Doebrich, Jeff L.

2011-01-01

Centuries before it was identified as an element, zinc was used to make brass (an alloy of zinc and copper) and for medicinal purposes. Metallic zinc and zinc oxide were produced in India sometime between the 11th and 14th centuries and in China in the 17th century, although the discovery of pure metallic zinc is credited to the German chemist Andreas Marggraf, who isolated the element in 1746. Refined zinc metal is bluish-white when freshly cast; it is hard and brittle at most temperatures and has relatively low melting and boiling points. Zinc alloys readily with other metals and is chemically active. On exposure to air, it develops a thin gray oxide film (patina), which inhibits deeper oxidation (corrosion) of the metal. The metal's resistance to corrosion is an important characteristic in its use.

Suplementos Minerales a partir de Anamú Petiveria Alliacea l.) y Plátano (Mussa Paradisí-aca l.)

OpenAIRE

Bárbara Luna; María Cristina Melo; Erlinda Handal; Estevan Pérez; Ana C. Rodriguez

2005-01-01

Es muy conocido en el mundo el uso de los suplementos nutricionales debido al papel que representan como complementos de la dieta cuando esta no es suficiente para satisfacer los requerimientos nutricionales diarios del hombre, de sustancias tales como los minerales, vitaminas, proteínas, etc., que por la importancia que tienen en el metabolismo se consideran esenciales para la vida. Entre otros minerales, se consideran esenciales para aquel, hierro, zinc, cobre, manganeso, selenio, cromo, co...

Dietary Zinc Intake and Plasma Zinc Concentrations in Children with Short Stature and Failure to Thrive.

Science.gov (United States)

Yazbeck, Nadine; Hanna-Wakim, Rima; El Rafei, Rym; Barhoumi, Abir; Farra, Chantal; Daher, Rose T; Majdalani, Marianne

2016-01-01

The burden of zinc deficiency on children includes an increased incidence of diarrhea, failure to thrive (FTT) and short stature. The aim of this study was to assess whether children with FTT and/or short stature have lower dietary zinc intake and plasma zinc concentrations compared to controls. A case-control study conducted at the American University of Beirut Medical Center included 161 subjects from 1 to 10 years of age. Cases had a statistically significant lower energy intake (960.9 vs. 1,135.2 kcal for controls, p = 0.010), lower level of fat (30.3 vs. 36.5 g/day, p = 0.0043) and iron intake (7.4 vs. 9.1 mg/day, p = 0.034). There was no difference in zinc, copper, carbohydrate and protein intake between the 2 groups. The plasma zinc concentration did not differ between the cases and controls (97.4 vs. 98.2 μg/dl, p = 0.882). More cases had mild-to-moderate zinc deficiency when compared to controls with 10.3 vs. 3.6%, p = 0.095. Our study did not show statistically significant difference in dietary zinc intake and plasma zinc concentrations between children with FTT and/or short stature compared to healthy controls. A prospective study is planned to assess the effect of zinc supplementation on growth parameters in FTT children. © 2016 S. Karger AG, Basel.

Radioactive zinc in soil-plant relationship studies

International Nuclear Information System (INIS)

Karimian, N.

1986-01-01

Zinc is one of the elements whose essentiality for plant growth and development has been proved beyond any doubt. Plant life and consequently the crop yield is impossible without zinc. The results of chemical, greenhouse, and field experiments on soils of Shiraz show that their level of available zinc for some crops is inadequate, despite the fact that the total amount of zinc in these soils may be relatively high. Obtaining the maximum yield, therefore, requires that either supplemental zinc be applied as chemical fertilizers or make the endogenous zinc more available to plants through some management practices. One of the isotopes of zinc, i.e. 65 Zn, is radioactive and has a detectable radiation which makes it suitable for tracer studies of zinc in soil, water, plant and animal. These studies help in understanding the soil plant relationships of zinc which in turn help to determine the optimum conditions of obtaining maximum yield. This paper presents and analyzes the results of some selected experiments to show different techniques of using radioactive zinc in understanding the behavior of zinc in soil and plant. Suggestions are also made of using this radioisotope in understanding the reactions of zinc in soils of Iran

PIGMENTOS Y PINTURAS DE MINERAL DE COBRE EN LA REGIÓN DE TARAPACÁ, NORTE DE CHILE: NUEVOS DATOS PARA UNA TECNOLOGÍA PIGMENTARIA PREHISPÁNICA

OpenAIRE

Sepúlveda,Marcela; Figueroa,Valentina; Cárcamo,José

2014-01-01

La explotación de los recursos minerales de cobre en el norte de Chile implicó la producción de pigmentos azules y verdes identificados, hasta ahora, en pintura rupestre, en nódulos y en estado de polvo al interior de contenedores de cuero provenientes de distintos cementerios de la cuenca del río Loa, región de Antofagasta, desierto de Atacama. En este artículo, se presentan los primeros resultados de análisis físico-químicos de pintura verde aplicada sobre distintos soportes de cuero: másca...

The effect of oral zinc loading on the absorption of 65Zinc in the rat

International Nuclear Information System (INIS)

Hoyer, H.; Weismann, K.

1979-01-01

Seven groups of 8 rats each were orally loaded with zinc, the daily dose varying from 1.8 to 58 mg, corresponding to about 3 to 100 times of their estimated daily intake of zinc. To record the absorption of zinc, the rats were given a single dose of 65 Zn. The rentention of the isotope was measured in a whole animal counter at regular intervals. The dose of 58mg was obviously toxis, since half of the animals died within 5 days. The net absorption of zinc in the remaining experimental groups was found to vary from about 7% in the group receiving the smallest loading dose to 1.8% in the group receiving the highest dose. From the absorption values, as determined by extrapolation of semilog retention curves, the total amount of absorbed zinc was estimated. It was found to differ from about 170μg to about 530μg zinc daily, increasing three times as the loading dose was increased 16 times. This discrepancy suggests the existence of regulatory mechanisms of the absorption of zinc from the intestine. (orig.) [de

Medicago truncatula Zinc-Iron Permease6 provides zinc to rhizobia-infected nodule cells.

Science.gov (United States)

Abreu, Isidro; Saéz, Ángela; Castro-Rodríguez, Rosario; Escudero, Viviana; Rodríguez-Haas, Benjamín; Senovilla, Marta; Larue, Camille; Grolimund, Daniel; Tejada-Jiménez, Manuel; Imperial, Juan; González-Guerrero, Manuel

2017-11-01

Zinc is a micronutrient required for symbiotic nitrogen fixation. It has been proposed that in model legume Medicago truncatula, zinc is delivered by the root vasculature into the nodule and released in the infection/differentiation zone. There, transporters must introduce this element into rhizobia-infected cells to metallate the apoproteins that use zinc as a cofactor. MtZIP6 (Medtr4g083570) is an M. truncatula Zinc-Iron Permease (ZIP) that is expressed only in roots and nodules, with the highest expression levels in the infection/differentiation zone. Immunolocalization studies indicate that it is located in the plasma membrane of nodule rhizobia-infected cells. Down-regulating MtZIP6 expression levels with RNAi does not result in any strong phenotype when plants are fed mineral nitrogen. However, these plants displayed severe growth defects when they depended on nitrogen fixed by their nodules, losing of 80% of their nitrogenase activity. The reduction of this activity was likely an indirect effect of zinc being retained in the infection/differentiation zone and not reaching the cytosol of rhizobia-infected cells. These data are consistent with a model in which MtZIP6 would be responsible for zinc uptake by rhizobia-infected nodule cells in the infection/differentiation zone. © 2017 John Wiley & Sons Ltd.

BWR fuel experience with zinc injection

International Nuclear Information System (INIS)

Levin, H.A.; Garcia, S.E.

1995-01-01

In 1982 a correlation between low primary recirculation system dose rates in BWR's and the presence of ionic zinc in reactor water was identified. The source of the zinc was primarily from Admiralty brass condensers. Plants with brass condensers are called ''natural zinc'' plants. Brass condensers were also a source of copper that was implicated in crude induced localized corrosion (CILC) fuel failures. In 1986 the first BWR intentionally injected zinc for the benefits of dose rate control. Although zinc alone was never implicated in fuel degradation of failures, a comprehensive fuel surveillance program was initiated to monitor fuel performance. Currently there are 14 plants that are injecting zinc. Six of these plants are also on hydrogen water chemistry. This paper describes the effect on both Zircaloy corrosion and the cruding characteristics as a result of these changes in water chemistry. Fuel rod corrosion was found to be independent of the specific water chemistry of the plants. The corrosion behavior was the same with the additions of zinc alone or zinc plus hydrogen and well within the operating experience for fuel without either of these additions. No change was observed in the amounts of crude deposited on the fuel rods, both for the adherent and loosely held deposits. One of the effects of the zinc addition was the trend to form more of the zinc rich iron spinel in the fuel deposits rather than the hematite deposits that are predominantly formed with non additive water chemistry

Comparative effects of zinc oxide nanoparticles and dissolved zinc on zebrafish embryos and eleuthero-embryos: Importance of zinc ions

NARCIS (Netherlands)

Brun, N.R.; Lenz, M.; Wehrli, B.; Fent, K.

2014-01-01

The increasing use of zinc oxide nanoparticles (nZnO) and their associated environmental occurrence make it necessary to assess their potential effects on aquatic organisms. Upon water contact, nZnO dissolve partially to zinc (Zn(II)). To date it is not yet completely understood, whether effects of

Endogenous zinc excretion in relation to various levels of dietary zinc intake in the mink (Mustela vison)

International Nuclear Information System (INIS)

Mejborn, H.

1990-01-01

Endogenous zinc excretion was studied in adult male mink fed experimental diets for 73 d, including a collection period from d 69 to 73. Dietary zinc levels were 2.8, 26 or 121 mg/kg wet weight. In accordance with the results of a methodological study, also reported here, the animals had an intramuscular injection of 65ZnCl2 12 d before the start of the collection period. Total fecal (endogenous + unabsorbed) zinc excretion for d 69-73 in the three groups was 2.3, 20.4 and 91.0 mg. The endogenous zinc excretion was 1.3, 2.0 and 6.4 mg, corresponding to 80.8, 10.6 and 6.4% of the zinc intake. Thus, the endogenous excretion was mainly important for the zinc homeostasis at low zinc intake, whereas at high intake the homeostasis was regulated via absorption from the digestive tract. The overall conclusion of the experiment was that mink are comparable to other species (including man) in regard to mechanisms controlling zinc homeostasis

Improved colorimetric determination of serum zinc.

Science.gov (United States)

Johnson, D J; Djuh, Y Y; Bruton, J; Williams, H L

1977-07-01

We show how zinc may easily be quantified in serum by first using an optimum concentration of guanidine hydrochloride to cause release of zinc from proteins, followed by complexation of released metals with cyanide. The cyanide complex of zinc is preferentially demasked with chloral hydrate, followed by a colorimetric reaction between zinc and 4-(2-pyridylazo)resorcinol. This is a sensitive water-soluble ligand; its complex with zinc has an absorption maximum at 497 nm. Values found by this technique compare favorably with those obtained by atomic absorption spectroscopy.

Photovoltaic cells employing zinc phosphide

Science.gov (United States)

Barnett, Allen M.; Catalano, Anthony W.; Dalal, Vikram L.; Masi, James V.; Meakin, John D.; Hall, Robert B.

1984-01-01

A photovoltaic cell having a zinc phosphide absorber. The zinc phosphide can be a single or multiple crystal slice or a thin polycrystalline film. The cell can be a Schottky barrier, heterojunction or homojunction device. Methods for synthesizing and crystallizing zinc phosphide are disclosed as well as a method for forming thin films.

ZINC-INDUCED HYPERLEPTINEMIA IN RATS RELATED TO THE AMELIORATION OF SUCROSE-INDUCED OBESITY WITH ZINC REPLETION

International Nuclear Information System (INIS)

HEIBASHY, M.I.; EL-NAHLA, A.M.; ASHOUR, I.; SALEH, SH.Y.A.

2008-01-01

Thirty adult albino rats (Rattus rattus) at 6 weeks of age were divided into three groups (ten for each). The first group was fed a standard laboratory diet for 8 weeks (control). The second group was made obese by giving them 32% sucrose solution in addition to the standard laboratory diet .The third group was received zinc supplementation (50 mg zinc acetate/ litre) with their sucrose solution. Body weight of all rats was measured weekly for 8 weeks. At 14 weeks of age, rats were killed and fasting blood samples were obtained. Serum glucose, insulin, cholesterol, triglyceride, leptin, tumour necrosis factor-α and zinc were measured.Results showed remarkable changes in body weights in sucrose fed rats only when compared to control and supplemented zinc rats group. Serum glucose, insulin, cholesterol and triglycerides were significantly increased in sucrose fed rats than both control and sucrose with zinc group. Serum leptin showed significant increase in sucrose fed rats than control and also showed higher significant value in sucrose fed rats supplemented with zinc comparing with sucrose fed rats and control ones. Tumour necrosis factor-? did not show any significant difference between all groups. Serum zinc concentration was decreased significantly in sucrose fed rats as compared to control. On the other hand, it was increased significantly in sucrose fed rats supplemented with zinc than other both groups. It could be concluded that zinc supplementation induced hyperleptinemia caused ameliorating effects in obese rats

The effects of Zinc supplementation on serum zinc, alkaline phosphatase activity and fracture healing of bones

International Nuclear Information System (INIS)

Sadighi, A.; Moradi, A.; Roshan, Marjan M.; Ostadrahimi, A.

2009-01-01

Objective was to determine the effect of zinc supplementation on callus information, serum zinc and alkaline phosphatase activity in humans. This randomized, double-blind, placebo controlled clinical trial was conducted on 60 patients with traumatic bone fracture referred to Shohada Hospital of Tabriz, Iran from August to December 2007. Subjects were randomly divided into 2 groups: cases (n=30), receiving one capsule of zinc sulfate consists of 50 mg zinc each day and the controls (n=30), receiving placebo for 60 days. Individual and clinical information was determined by a questionnaire: nutritional intake by 3 days food records at the beginning and the end of trial. Serum zinc and alkaline phosphatase was measured by atomic absorption spectroscopy and by enzymatic method. Callus information during fracture healing was evaluated by radiography of the bone. There was no significant difference in physical activity, gender, age, type of fractures and nutrient intake, between the 2 groups. The administration of zinc caused a significant elevation of serum zinc and alkaline phosphatase activity. Assessment of bone x-rays showed a significant progress in callus formation in cases compared to the controls. This study shows that zinc supplementation can stimulate fracture healing, however, it needs further study. (author)

Electrodeposition of zinc--nickel alloys coatings

Energy Technology Data Exchange (ETDEWEB)

Dini, J W; Johnson, H R

1977-10-01

One possible substitute for cadmium in some applications is a zinc--nickel alloy deposit. Previous work by others showed that electrodeposited zinc--nickel coatings containing about 85 percent zinc and 15 percent nickel provided noticeably better corrosion resistance than pure zinc. Present work which supports this finding also shows that the corrosion resistance of the alloy deposit compares favorably with cadmium.

Zinc and immunity: An essential interrelation.

Science.gov (United States)

Maares, Maria; Haase, Hajo

2016-12-01

The significance of the essential trace element zinc for immune function has been known for several decades. Zinc deficiency affects immune cells, resulting in altered host defense, increased risk of inflammation, and even death. The micronutrient zinc is important for maintenance and development of immune cells of both the innate and adaptive immune system. A disrupted zinc homeostasis affects these cells, leading to impaired formation, activation, and maturation of lymphocytes, disturbed intercellular communication via cytokines, and weakened innate host defense via phagocytosis and oxidative burst. This review outlines the connection between zinc and immunity by giving a survey on the major roles of zinc in immune cell function, and their potential consequences in vivo. Copyright © 2016 Elsevier Inc. All rights reserved.

Hidroxilación de fenol con catalizadores ZSM-5 modificado con cobre

Directory of Open Access Journals (Sweden)

César Augusto Caro

2005-01-01

Full Text Available Se sintetizaron varios catalizadores Cu-ZSM-5 con diferentes relaciones Si/Al y Si/Cu. Usando metilamina o hidróxido de sodio como agente mineralizante. Los catalizadores se caracterizaron por DRX, IR, análisis BET, UV-VIS y análisis elemental. El desempeño catalítico de los catalizadores sintetizados se evaluó en la hidroxilación de fenol con H2O2. Se encontró que la relación catecol (CAT/(hidroquinona (HQ + p-benzoquinona (PBQ aumentó con el contenido de agua, presentó un máximo cuando la relación en peso de agua/fenol fue de 53/1 y se favoreció a altas temperaturas, con el aumento del contenido de aluminio o con la disminución en el contenido de catalizador. El contenido de cobre no fue un factor determinante para la conversión ni para la selectividad en la hidroxilación de fenol. La producción de la p-benzoquinona (PBQ, producto de oxidación de la hidroquinona, fue mínimo cuando se usaron las siguientes condiciones: 80 ºC, fenol: 1 mmol, relación molar fenol/H2O2 de 3/1, catalizador: 20 mg, agua: 5 g, tiempo de reacción: 4 h.

Zinc Status of Vegetarians during Pregnancy: A Systematic Review of Observational Studies and Meta-Analysis of Zinc Intake.

Science.gov (United States)

Foster, Meika; Herulah, Ursula Nirmala; Prasad, Ashlini; Petocz, Peter; Samman, Samir

2015-06-05

Pregnant women are vulnerable to a low zinc status due to the additional zinc demands associated with pregnancy and foetal development. The present systematic review explores the relationship between habitual vegetarian diets and dietary zinc intake/status during pregnancy. The association between vegetarian diets and functional pregnancy outcome also is considered. A literature search was conducted of MEDLINE; PubMed; Embase; the Cochrane Library; Web of Science; and Scopus electronic databases up to September 2014. Six English-language observational studies qualified for inclusion in the systematic review. A meta-analysis was conducted that compared the dietary zinc intake of pregnant vegetarian and non-vegetarian (NV) groups; the zinc intake of vegetarians was found to be lower than that of NV (-1.38 ± 0.35 mg/day; p vegetarian nor NV groups met the recommended dietary allowance (RDA) for zinc. In a qualitative synthesis; no differences were found between groups in serum/plasma zinc or in functional outcomes associated with pregnancy. In conclusion; pregnant vegetarian women have lower zinc intakes than NV control populations and both groups consume lower than recommended amounts. Further information is needed to determine whether physiologic adaptations in zinc metabolism are sufficient to meet maternal and foetal requirements during pregnancy on a low zinc diet.

Análisis del proceso de electro-obtención de cátodos de cobre a través de la utilización de técnicas de diseño experimental

Directory of Open Access Journals (Sweden)

Carlos Torres Navarro

2004-07-01

Full Text Available Este estudio fue desarrollado en una empresa minera ubicada en el norte de Chile con el propósito de identificar las variables que tienen mayor incidencia en la producción de cátodos de cobre de alta calidad, específicamente se hizo hincapié en  los porcentajes de plomo y azufre que son las impurezas relevantes en la discriminación de cátodos de alta calidad, considerando la Norma L.M.E (London Metal Exchange, que rige el mercado del cobre. El experimento fue desarrollado utilizando un segmento de datos representativos de las condiciones actuales de operación bajo un enfoque de diseño experimental con dos niveles y con cuatro factores para el análisis del plomo y de seis factores para el caso del azufre. Los resultados obtenidos ofrecen un importante referente para orientar futuras acciones de mejoramiento de la calidad y productividad así como poder identificar  factores metalúrgicos que poseen un fundamento estadístico objetivo y, además, contar con ecuaciones preliminares para estimar porcentajes de impurezas ante eventuales cambios en las condiciones de operación.

Fortification of staple foods with zinc for improving zinc status and other health outcomes in the general population.

Science.gov (United States)

Shah, Dheeraj; Sachdev, Harshpal S; Gera, Tarun; De-Regil, Luz Maria; Peña-Rosas, Juan Pablo

2016-06-09

Zinc deficiency is a global nutritional problem, particularly in children and women residing in settings where diets are cereal based and monotonous. It has several negative health consequences. Fortification of staple foods with zinc may be an effective strategy for preventing zinc deficiency and improving zinc-related health outcomes. To evaluate the beneficial and adverse effects of fortification of staple foods with zinc on health-related outcomes and biomarkers of zinc status in the general population. We searched the following databases in April 2015: Cochrane Central Register of Controlled Trials (CENTRAL, Issue 3 of 12, 2015, the Cochrane Library), MEDLINE & MEDLINE In Process (OVID) (1950 to 8 April 2015), EMBASE (OVID) (1974 to 8 April 2015), CINAHL (1982 to April 2015), Web of Science (1900 to 9 April 2015), BIOSIS (1969 to 9 April 2015), POPLINE (1970 to April 2015), AGRICOLA, OpenGrey, BiblioMap, and Trials Register of Promoting Health Interventions (TRoPHI), besides regional databases (April 2015) and theses. We also searched clinical trial registries (17 March 2015) and contacted relevant organisations (May 2014) in order to identify ongoing and unpublished studies. We included randomised controlled trials, randomised either at the level of the individual or cluster. We also included non-randomised trials at the level of the individual if there was a concurrent comparison group. We included non-randomised cluster trials and controlled before-after studies only if there were at least two intervention sites and two control sites. Interventions included fortification (central/industrial) of staple foods (cereal flours, edible fats, sugar, condiments, seasonings, milk and beverages) with zinc for a minimum period of two weeks. Participants were members of the general population who were over two years of age (including pregnant and lactating women) from any country. Two review authors independently assessed the eligibility of studies for inclusion

Status of zinc injection in PWRs

Energy Technology Data Exchange (ETDEWEB)

Bergmann, C.A. [Westinghouse Electric Co., Pittsburgh, PA (United States)

1995-03-01

Based on laboratory and other studies, it was concluded that zinc addition in a PWR primary coolant should result in reduced Alloy 600 PWSCC and general corrosion rates of the materials of construction. Because of these positive results, a Westinghouse Owner`s Subgroup, EPRI, and Westinghouse provided funds to continue the development and application of zinc in an operating plant. As part of the program, Southern Operating Nuclear Company agreed to operate the Farley 2 plant with zinc addition as a demonstration test of the effectiveness of zinc. Since zinc is incorporated in the corrosion oxide film on the primary system surfaces and Farley 2 is a mature plant, it was estimated that about 10 kgs of zinc would be needed to condition the plant before an equilibrium value in the coolant would be reached. The engineered aspects of a Zinc Addition and Monitoring System (ZAMS) considered such items as the constitutents, location, sizing and water supply of the ZAMS. Baseline data such as the PWSCC history of the Alloy 600 steam generator tubing, fuel oxide thickness, fuel crud deposits, radiation levels, and RCP seal leak-off rates were obtained before zinc addition is initiated. This presentation summarizes some of the work performed under the program, and the status of zinc injection in the Farley 2 plant.

Promoción del crecimiento en plantas de Capsicum annuum por nanopartículas de óxido de zinc

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B. Méndez-Argüello

2016-01-01

Full Text Available Las aplicaciones de la nanotecnología (NT en los sistemas agrícolas son diversas, ofreciendo el potencial para mejorar significativamente su productividad y eficiencia al reducir costos y cantidades de agroquímicos aplicados. Las nanopartículas (NPs metálicas de óxido de zinc, cobre y fierro, ya sean puras o mezcladas con plata, están siendo estudiadas globalmente por su potencial agrícola como promotores de crecimiento, nanofertilizantes y antimicrobiales. Considerando lo antes señalado, el objetivo de este trabajo fue evaluar el efecto de NPs de óxido de zinc puras (NPsZnO y con plata (NPsZnO+Ag en el crecimiento de plantas de chile (Capsicum annuum. La síntesis y caracterización de las NPs mencionadas se realizó mediante el método de sol-gel. La aplicación foliar de las NPs a las plantas se hizo semanalmente; el diseño experimental empleado fue completamente al azar con cuatro tratamientos y cinco repeticiones. Los datos obtenidos se procesaron mediante un análisis de varianza y prueba de rango múltiple Tukey (p≤0.05. Los resultados señalan que las plantas expuestas a la aplicación de NPsZnO + Ag al 2.5% en peso, tuvieron significativamente mayor crecimiento y producción de biomasa en comparación con las plantas del tratamiento control, mostrando valores superiores de altura (16.8%, área foliar (30.3%, producción de biomasa total (59.5%, biomasa seca de raíz (112.5%, biomasa seca de tallo (76% y longitud de raíz (24.4%. También se observó un incremento del índice de clorofila (8% y número de hojas (32.6%. El efecto promotor de crecimiento de las NPs aplicadas podría atribuirse a la actividad del zinc como precursor de la producción de auxinas que promueven división y elongación celular; así como por su influencia en la reactividad del ácido indolacético, el cual actúa como fitoestimulante hormonal. También puede ser factible que las NPs estudiadas estén involucradas en la biosíntesis de citoquininas

Further studies on selective radioprotection by organic zinc salts and synergism of zinc aspartate with WR 2721

International Nuclear Information System (INIS)

Floersheim, G.L.; Bieri, A.

1990-01-01

Protection of the haematocrit and thrombocytes by small doses of the aminothiol radioprotector WR 2721 was markedly improved by the concomitant administration of small doses of zinc aspartate. Zinc aspartate was the only one of the tested zinc salts not inhibiting the regression induced by radiotherapy of human tumours grown as xenografts in immunosuppressed mice. This also applied to zinc aspartate with WR 2721. A dose of zinc aspartate which afforded synergistic haematological protection did not enhance the toxicity of WR 2721. The synergism of zinc aspartate with WR 2721 and the differential radioprotection of the combined protocol may make it possible in clinical cancer radiotherapy to obtain selective radioprotection at a lower toxicity giving an improved therapeutic ratio compared with WR 2721 alone. (author)

Serum zinc levels in gestational diabetes

Directory of Open Access Journals (Sweden)

Rahimi Sharbaf F

2008-12-01

Full Text Available "nBackground: Maternal zinc deficiency during pregnancy has been related to adverse pregnancy outcomes. Most studies in which pregnant women have been supplemented with zinc to examine its effects on the outcome of the pregnancy have been carried out in industrialized countries and the results have been inconclusive. It has been shown that women with gestational diabetes (GDM have lower serum zinc levels than healthy pregnant women, and higher rates of macrosomia. Zinc is required for normal glucose metabolism, and strengthens the insulin-induced transportation of glucose into cells by its effect on the insulin signaling pathway. The purpose of this study was to assess the serum zinc levels of GDM patients and evaluate the effect of zinc supplementation. "nMethods: In the first stage of this prospective controlled study, we enrolled 70 women who were 24-28 weeks pregnant at the Prenatal Care Center of Mirza Kochak Khan Hospital, Tehran, Iran. The serum zinc level of each subject was determined. In the second stage, among these 70 subjects, the diabetics receiving insulin were divided into two groups, only one of which received a zinc supplement and the other group was the control group. Birth weight of neonates and insulin dosages were recorded. "nResults: The mean serum zinc level in the GDM group was lower than that of the control group (94.83 vs. 103.49mg/dl, respectively and the mean birth weight of neonates from the GDM women who received the zinc supplement was lower than that of the control group (3849g vs. 4136g. The rate of macrosomia was lower in the zinc supplemented group (20% vs. 53%. The mean of increase of insulin after receiving the zinc supplement was lower (8.4u vs. 13.53. "nConclusion: Maternal insulin resistance is associated with the accumulation of maternal fat tissue during early stages of pregnancy and greater fetoplacental nutrient availability in later stages, when 70% of fetal growth occurs, resulting in macrosomia. In

Zinc phosphate conversion coatings

Science.gov (United States)

Sugama, Toshifumi

1997-01-01

Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate .alpha.-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal.

Correlação entre características de latossolos e parâmetros de equações de adsorção de cobre e zinco Correlation between characteristics of latosols from Minas Gerais State, Brazil, and parameters of adsorption equations of copper and zinc

Directory of Open Access Journals (Sweden)

C. W. A. Nascimento

2004-12-01

Full Text Available A adsorção de Cu e Zn é um dos principais fenômenos responsáveis pela disponibilidade desses elementos para as plantas. Portanto, estudos sobre a adsorção desses elementos em solos podem ser ferramentas úteis para compreensão da relação entre características dos solos e retenção desses micronutrientes. Nesse sentido, o presente trabalho objetivou caracterizar a adsorção de Cu e Zn em amostras de seis Latossolos de Minas Gerais e as influências de características dos solos sobre os parâmetros de adsorção obtidos pelas equações de Langmuir e de Freundlich. Para tanto, foram utilizadas soluções de cloreto de cobre e cloreto de zinco nas concentrações 0, 10, 20, 40, 60, 80, 100, 120 e 140 mg L-1, ajustadas a pH 5,5. As equações de Langmuir e Freundlich foram eficientes na determinação dos parâmetros de adsorção de Zn e Cu, sendo os teores de argila e de matéria orgânica, respectivamente, as características mais bem relacionadas com a capacidade de adsorção desses elementos pelos solos. Os solos estudados apresentaram maior energia de ligação dos sítios de troca e maior capacidade de adsorção máxima para Cu relativamente ao Zn. O P remanescente não se correlacionou com os parâmetros de adsorção de Zn, em virtude, provavelmente, da influência da matéria orgânica em sua determinação. Este fato pode limitar sua eficiência na previsão da adsorção deste elemento em solos com alto teor de C orgânico.Copper and zinc adsorption is one of the main phenomena controlling the availability of these metals to plants. As a consequence, studies on the adsorption of such elements in soils may be useful tools to understand the relationship between soil characteristics and retention of these micronutrients. The present study examined the adsorption of copper and zinc in six Latosols (Oxisols with a wide range of chemical properties. Solutions containing different Cu and Zn concentrations (0, 10, 20, 40, 60, 80

Depósitos de escarnitos mineralizados em ferro e cobre do arco magmático de Santa Quitéria, Ceará, Provincia Borborema do nordeste do Brasil

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Clovis Vaz Parente

Full Text Available Resumo Depósitos de escarnitos mineralizados em W-Mo da Província Borborema são conhecidos desde os anos 40. Entretanto, até a execução deste trabalho, não se tinha registros desses depósitos mineralizados em Fe-Cu. No Ceará, as primeiras ocorrências e/ou depósitos de escarnitos ricos em ferro e cobre foram identificadas recentemente no Arco Magmático Continental de Santa Quitéria, considerado produto de evolução de vários arcos magmáticos, variando de arco juvenil (870 - 800 Ma a colisão continental (625 - 600 Ma. Os escarnitos estão associados às rochas calcissilicáticas e mármores dolomíticos e/ou calcíticos, recortadas por quartzo monzonitos neoproterozóicos cedo a tardi-colisionais. São encontrados todos os tipos do sistema escarnítico como endoescarnitos, hornfels, escarnóides e exoescarnitos. Os exoescarnitos apresentam duas associações minerais, que refletem protólitos carbonáticos distintos: uma composta por clinopiroxênio-granada (estágio progradante e magnetita-pirrotita-calcopirita-pirita-biotita (estágio retrogradante, característica de protólito calcítico, e outra formada por olivina-espinélio-diopsidio na fase progradante e serpentina na fase retrogradante, representativa de protólito dolomítico. As granadas, em parte zonadas, exibem composição dominada por andradita (82 - 52 mol%, seguida por grossularita (16 - 45mol% e, em proporção menor, piropo (2 - 3 mol%. O piroxênio do protólito calcítico é típico da série diopsídio-hedenbergita, com composição média Diopsídio46Hedenbergita52Johannsenita2. Três tipos de minério magnetítico são encontrados: i magnetito bandado; ii magnetito disseminado; iii magnetito maciço filoneano. Ocorre ainda um minério sulfetado de cobre com e sem magnetita associado, e blocos de gossans. Os dados geológicos e metalogenéticos obtidos indicam que a gênese destes escarnitos está associada à influência dos granitos monzoníticos tardi

First Principles Investigation of Zinc-anode Dissolution in Zinc-air Batteries

DEFF Research Database (Denmark)

Siahrostami, Samira; Tripkovic, Vladimir; Lundgård, Keld Troen

2013-01-01

With surging interest in high energy density batteries, much attention has recently been devoted to metal-air batteries. The zinc-air battery has been known for more than hundred years and is commercially available as a primary battery, but recharging has remained elusive; in part because...... the fundamental mechanisms still remain to be fully understood. Here, we present a density functional theory investigation of the zinc dissolution (oxidation) on the anode side in the zinc-air battery. Two models are envisaged, the most stable (0001) surface and a kink surface. The kink model proves to be more....... The applied methodology provides new insight into computational modelling and design of secondary metal-air batteries....

The effect of severe zinc deficiency and zinc supplement on spatial learning and memory.

Science.gov (United States)

Tahmasebi Boroujeni, S; Naghdi, N; Shahbazi, M; Farrokhi, A; Bagherzadeh, F; Kazemnejad, A; Javadian, M

2009-07-01

Zinc deficiency during pregnancy and during lactation has been shown to impair cognitive function and motor activity in offspring rats. In the present study, the effect of zinc deficiency and zinc supplement on spatial learning and memory in Morris Water Maze (MWM) and motor activity in open field were investigated. Pregnant rats after mating were divided to three groups. Control group fed a standard diet and a zinc deficient (ZnD) group fed a diet deficient in zinc (0.5-1.5 ppm) and a zinc supplement (ZnS) group fed a standard diet and enhanced zinc in the drinking water (10 ppm). All the diets were exposed during the last trisemester of pregnancy and during lactation. Rat's offspring in these groups were tested for spatial learning and memory in MWM at post natal day (PND) 56 and were tested for motor activity in open field at PND 66.The Escape Latency (EL) and Traveled Distance (TD) in the ZnD group were increased but Percentage of Time Spent in the target quadrant (PTS) was decreased compared to the control group. In addition, these were no significant differences in EL and TD, but PTS had significant increase in ZnS compared to the control group. In the open field, Total Distance Moved (TDM) and Time of Motor Activity (TMA) for the ZnD were decreased compared to the control group, but there were no significant differences in TDM and TMA between control and ZnS groups. These findings suggest that zinc deficiency during the last trimester of pregnancy and during lactation impaired spatial learning and memory in their offsprings and has also negative effect on motor activity. In addition, ZnS has a significant effect on spatial learning and memory but no effect on motor activity in their offsprings.

Effect of zinc supplementation on body mass index and serum levels of zinc and leptin in pediatric hemodialysis patients

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El-Shazly AN

2015-12-01

Full Text Available Ahmed Nabih El-Shazly,1 Soha Abd El-Hady Ibrahim,1 Ghada Mohamed El-Mashad,2 Jehan H Sabry,3 Nashwa Said Sherbini11Department of Pediatrics, Faculty of Medicine, Benha University, Banha, 2Department of Pediatrics, Faculty of Medicine, Menoufia University, Shibin Al Kawm, 3Department of Clinical and Chemical Pathology, Faculty of Medicine, Benha University, Banha, Egypt Introduction: Zinc is an essential trace element for human nutrition, and its deficiency is associated with anorexia, poor food efficiency, growth retardation, and impaired neurological and immune systems. The zinc-deficiency rate is particularly high in many disease states, such as with end-stage renal disease patients undertaking hemodialysis. The aim of this study was to determine the effect of zinc supplementation on body mass index (BMI and serum levels of zinc and leptin in pediatric hemodialysis patients. Patients and methods: This was a prospective clinical trial study in which 60 hemodialysis patients were randomly divided into two groups: group I received 50–100 mg zinc sulfate (equivalent to 11–22 mg elemental zinc according to age, sex, and nutritional status of the child; and group II received placebo (cornstarch twice daily for 90 days. Anthropometric measurements were taken, and serum zinc and leptin levels were determined by colorimetric test with 5-Br-3'-phosphoadenosine-5'-phosphosulfate and enzyme-linked immunosorbent assay, respectively, at days 0 and 90 of the study. Results: Zinc supplementation resulted in a significant increase in mean serum zinc level and BMI. Serum leptin decreased significantly after supplementation in children under hemodialysis. A significant negative correlation was observed between serum zinc and leptin levels as a result of zinc supplementation. Conclusion: There was an increase in serum zinc level and BMI and decreased serum leptin after zinc supplementation in children under hemodialysis. Keywords: serum zinc, serum leptin

Construction and application of a zinc-specific biosensor for assessing the immobilization and bioavailability of zinc in different soils

International Nuclear Information System (INIS)

Liu Pulin; Huang Qiaoyun; Chen Wenli

2012-01-01

The inducibility and specificity of different czcRS operons in Pseudomonas putida X4 were studied by lacZ gene fusions. The data of β-glycosidase activity confirmed that the czcR3 promoter responded quantitatively to zinc. A zinc-specific biosensor, P. putida X4 (pczcR3GFP), was constructed by fusing a promoterless enhanced green fluorescent protein (egfp) gene with the czcR3 promoter in the chromosome of P. putida X4. In water extracts of four different soils amended with zinc, the reporter strain detected about 90% of the zinc content of the samples. Both the bioavailability assessment and the sequential extraction analysis demonstrated that the immobilization of zinc was highly dependent on the physico-chemical properties of soils. The results also showed that the lability of zinc decreased over time. It is concluded that the biosensor constitutes an alternative system for the convenient evaluation of zinc toxicity in the environment. - Highlights: ► A zinc-specific bacterial biosensor was developed. ► Four spiked soils were used to test the application of this biosensor. ► The bioavailable zinc in soil-water extracts decreased due to aging. ► The immobilization and speciation of zinc were highly dependent on the soil type. - The immobilization and bioavailability of zinc in soil were investigated as a function of soil type and aging by a newly constructed zinc-specific biosensor coupled with chemical analysis.

Inhibitory zinc-enriched terminals in mouse spinal cord

DEFF Research Database (Denmark)

Danscher, G; Jo, S M; Varea, E

2001-01-01

The ultrastructural localization of zinc transporter-3, glutamate decarboxylase and zinc ions in zinc-enriched terminals in the mouse spinal cord was studied by zinc transporter-3 and glutamate decarboxylase immunohistochemistry and zinc selenium autometallography, respectively.The distribution...

Factors influencing zinc status of apparently healthy indians.

Science.gov (United States)

Agte, Vaishali V; Chiplonkar, Shashi A; Tarwadi, Kirtan V

2005-10-01

To identify dietary, environmental and socio-economic factors associated with mild zinc deficiency, three zinc status indices; erythrocyte membrane zinc (RBCMZn), plasma zinc and super oxide dismutase (SOD) were assessed in free living and apparently healthy Indian population. Dietary patterns of 232 men and 223 women (20-65 yr) from rural, industrial and urban regions of Western India were evaluated by food frequency questionnaire. RBCMZn was estimated using atomic absorption spectrometry, hemoglobin and serum ceruloplasmin by spectrophotometer. On a sub sample (48 men and 51 women) plasma zinc and SOD were also assessed. Mean RBCMZn was 0.5 +/- 0.1 micromols/g protein with 46% individuals showing zinc deficiency. Mean plasma zinc was 0.98 +/- 0.12 microg/mL with 25% men and 2.5% women having values below normal range. Mean SOD was 0.97 +/- 0.1 (u/mL cells). A significant positive correlation was observed between intakes of green leafy vegetables, other vegetables and milk products with RBCMZn status (p plasma zinc (p > 0.2). Cereal and legume intakes were negatively correlated with RBCMZn (p plasma zinc (p 0.2). Fruit and other vegetable intake were positively correlated with SOD (p Plasma zinc indicated positive association with zinc, thiamin and riboflavin intakes (p plasma zinc and SOD. Prominent determinants of zinc status were intakes of beta-carotene and zinc along with environmental conditions and family size.

Zinc absorption in inflammatory bowel disease

International Nuclear Information System (INIS)

Valberg, L.S.; Flanagan, P.R.; Kertesz, A.; Bondy, D.C.

1986-01-01

Zinc absorption was measured in 29 patients with inflammatory bowel disease and a wide spectrum of disease activity to determine its relationship to disease activity, general nutritional state, and zinc status. Patients with severe disease requiring either supplementary oral or parenteral nutrition were excluded. The mean 65ZnCl2 absorption, in the patients, determined using a 65Zn and 51Cr stool-counting test, 45 +/- 17% (SD), was significantly lower than the values, 54 +/- 16%, in 30 healthy controls, P less than 0.05. Low 65ZnCl2 absorption was related to undernutrition, but not to disease activity in the absence of undernutrition or to zinc status estimated by leukocyte zinc measurements. Mean plasma zinc or leukocyte zinc concentrations in patients did not differ significantly from controls, and only two patients with moderate disease had leukocyte zinc values below the 5th percentile of normal. In another group of nine patients with inflammatory bowel disease of mild-to-moderate severity and minimal nutritional impairment, 65Zn absorption from an extrinsically labeled turkey test meal was 31 +/- 10% compared to 33 +/- 7% in 17 healthy controls, P greater than 0.1. Thus, impairment in 65ZnCl2 absorption in the patients selected for this study was only evident in undernourished persons with moderate or severe disease activity, but biochemical evidence of zinc deficiency was uncommon, and clinical features of zinc depletion were not encountered

The zinc-myoglobin relationships in porcine muscles

International Nuclear Information System (INIS)

Fogd Joergensen, P.; Wegger, I.

1976-01-01

Zinc and myoglobin content in muscles from pigs were studied under various conditions. Zinc concentration was considerably higher in red than in white muscles. In muscles, where the metabolic pattern changes from glycolytic to oxidative during the period from birth to weaning, a simultaneous increase in zinc content was seen. A significant positive correlation exists between myoglobin and zinc content under normal conditions. However, while myoglobin concentration decreases due to iron deficiency anaemia no changes occur in zinc content. It is concluded that no functional link seems to exist between zinc metabolism and myoglobin synthesis in porcine muscles. (author)

Balance de nutrientes en la remolacha azucarera

OpenAIRE

López Conde, Marta

2016-01-01

Los nutrientes esenciales para el correcto desarrollo de una planta de remolacha azucarera se subdividen en dos grupos (macronutrientes y micronutrientes), dependiendo de la concentración necesaria para tener la cantidad suficiente para un correcto desarrollo. Dentro de los macronutrientes destacan el nitrógeno (N), el fósforo (P), el calcio (Ca), el magnesio (Mg) y el potasio (K). Dentro de los micronutrientes destacan el manganeso (Mn), el cobre (Cu) y el zinc (Zn). Estos nutrientes son abs...

Technical feasibility of using silver and copper ions electro generated in the microbiological control of cooling systems; Factibilidad tecnica para emplear iones plata y cobre electrogenerados en el control microbiologico de los sistemas de enfriamiento

Energy Technology Data Exchange (ETDEWEB)

Silva, Susana M; Martinez Meza, Esteban; Alvarez Gallegos, Alberto [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

2001-07-01

bacterial populations promoters of the microbiological influenced corrosion and the biological fouling at levels of 1000 c/ml and less, competing with the conventional cooling water treatment processes. Also, the adherence capacity of the biofilm on the surfaces of the cooling system would be seriously affected because the silver is adsorbed to the surface that contains it and still continues its bactericidal effect. Additionally, the coliform bacteria are reduced below the levels accepted by the Mexican Official Standard. A table of the silver required for disinfection of different water qualities is shown and another one on the evaluation of the process and finally one on the effectiveness of the process using the silver/copper system in residual water. [Spanish] El objetivo de este trabajo es determinar la factibilidad tecnica de sustituir el uso de cloro por otro biocida (ionizacion de plata o cobre) no peligroso en aguas de enfriamiento. Esta tecnica de ionizacion podria ser empleada para tratar el agua de procesos industriales en general. El agua empleada provino del agua de repuesto del sistema de enfriamiento de la Central Termoelectrica de Valle de Mexico (CTEVM) y agua residual de las plantas de tratamiento del Instituto Mexicano de Tecnologia del Agua (IMTA) y el Instituto de Investigaciones Electricas (IIE). Los tres tipos de agua empleados tienen caracteristicas fisicas, quimicas y biologicas similares. La metodologia usada fue la prueba de jarras y por sistema continuo. Se indica el analisis bacteriologico llegando a la conclusion. Los sistemas metalicos estudiados en el establecimiento del control microbiologico en el agua residual y agua de repuesto son plata, plata/cobre y cobre en los intervalos de concentracion de 200 mg/L a 3000 mg/L de plata y de 200 mg/L a 1200 mg/L de cobre. Los experimentos realizados en la prueba de jarras (sistema cerrado) se llevaron a cabo a dos temperaturas (25 {+-} 0.5 y 32 {+-} 0.5 ) sin controlar el pH; mientras que en el

Obtenção e caracterização de carvão ativado de caroço de buriti (Mauritia flexuosa L. f. para a avaliação do processo de adsorção de cobre (II Production and characterization of the activated carbon from buriti stone (Mauritia flexuosa L. f. to evaluate the adsorption's process of copper (II

Directory of Open Access Journals (Sweden)

Marcos Vinicios de Souza Pinto

2013-03-01

Full Text Available Na região amazônica, algumas indústrias despejam cobre nos corpos receptores que, em elevadas concentrações, é tóxico para os seres vivos. A remoção de cobre de efluentes industriais é realizada por diversos processos como a adsorção. Neste trabalho mostrou-se o resultado da adsorção de cobre (II em carvão ativado de caroço de buriti carbonizado a 400 °C e ativado a 900 °C. O carvão ativado foi caracterizado em termos de área específica, tamanho dos poros, densidades aparente e real, porosidade, microscopia eletrônica de varredura, conteúdo de cinzas, pH, umidade, carbono fixo e grupos funcionais de superfície. O estudo de equilíbrio de adsorção avaliou a influência do diâmetro das partículas do carvão, do tempo de contato adsorvente/adsorbato, do pH e da concentração inicial da solução de cobre (II sobre a remoção de cobre (II. Com base nos resultados, concluiu-se que há uma maior eficiência de remoção de cobre (II para diâmetro In the Amazon region some industries discharges copper into watercourse that in high concentrations is toxic to the biota. The removal of copper from industrial effluent is performed by several processes such as adsorption. This work shows the result of copper (II adsorption on activated carbon obtained from buriti kernel, carbonized at 400 °C and activated at 900 °C. The activated carbon was characterized according to specific area, pore size, apparent and real density, porosity, scanning electron microscopy, ash content, pH, moisture, fixed carbon and surface functional groups. The study of adsorption equilibrium evaluated the influence of the coal particles diameter, contact time adsorbent/adsorbate, pH and copper (II solution initial concentration on copper (II remotion. The results showed a higher removal efficiency of copper (II to the diameter D < 0.595 mm, contact time of 300 minutes, pH of 4.01 and the copper (II initial concentrations of 50 and 80 mg L-1. The

Non-Chromate Passivation of Zinc

DEFF Research Database (Denmark)

Tang, Peter Torben; Bech-Nielsen, G.

1993-01-01

Phos). The treatments are within the same concentration region, and they have a mutual pat-ent pending. Although some tests still need to be conducted, the following aspects are clear at the present time: The general appearance of the passivated zinc surface is very similar to a standard yellow chromate treatment...... successfully. The corrosion resistance against white rust on zinc and zinc alloys is just as good as that of yellow chromate, although the result de-pends on the corrosion test method as well as on the nature of the zinc substrate pas-sivated. The passivation procedure is simply a dip for approxi-mately 2...

Effects of serum zinc level on tinnitus.

Science.gov (United States)

Berkiten, Güler; Kumral, Tolgar Lütfi; Yıldırım, Güven; Salturk, Ziya; Uyar, Yavuz; Atar, Yavuz

2015-01-01

The aim of this study was to assess zinc levels in tinnitus patients, and to evaluate the effects of zinc deficiency on tinnitus and hearing loss. One-hundred patients, who presented to an outpatient clinic with tinnitus between June 2009 and 2014, were included in the study. Patients were divided into three groups according to age: Group I (patients between 18 and 30years of age); Group II (patients between 31 and 60years of age); and Group III (patients between 61 and 78years of age). Following a complete ear, nose and throat examination, serum zinc levels were measured and the severity of tinnitus was quantified using the Tinnitus Severity Index Questionnaire (TSIQ). Patients were subsequently asked to provide a subjective judgment regarding the loudness of their tinnitus. The hearing status of patients was evaluated by audiometry and high-frequency audiometry. An average hearing sensitivity was calculated as the mean value of hearing thresholds between 250 and 20,000Hz. Serum zinc levels between 70 and 120μg/dl were considered normal. The severity and loudness of tinnitus, and the hearing thresholds of the normal zinc level and zinc-deficient groups, were compared. Twelve of 100 (12%) patients exhibited low zinc levels. The mean age of the zinc-deficient group was 65.41±12.77years. Serum zinc levels were significantly lower in group III (p<0.01). The severity and loudness of tinnitus were greater in zinc-deficient patients (p=0.011 and p=0.015, respectively). Moreover, the mean thresholds of air conduction were significantly higher in zinc-deficient patients (p=0.000). We observed that zinc levels decrease as age increases. In addition, there was a significant correlation between zinc level and the severity and loudness of tinnitus. Zinc deficiency was also associated with impairments in hearing thresholds. Copyright © 2015 Elsevier Inc. All rights reserved.

Absorbed zinc and exchangeable zinc pool size are significantly greater in Pakistani infants receiving traditional complementary foods with zinc fortified micronutrient powder

International Nuclear Information System (INIS)

Ariff, Shabina; Soofi, Sajid; Bhutta, Zulfiqar; Krebs, Nancy; Westcott, Jamie

2014-01-01

Full text: Adequacy of zinc intake from breast milk alone becomes marginal in relation to infant requirements by around six months of age. Simple and cost effective strategies are needed at population level to ensure adequate intakes of zinc in infants and toddlers in populations at risk of zinc deficiency. We determined the amount of absorbed zinc (AZ) from a micronutrient powder (MNP) without and with 10 mg of zinc (MNP, MNP+Zn, respectively) added to local complementary foods used in Pakistan, and the impact on the exchangeable zinc pool (EZP) size. As a nested study within a large prospective cluster randomized trial, 6 month old infants were randomized to receive MNP or MNP+Zn. Stable isotope methodology was applied after ~ 3 and 9 months of use to measure AZ from MNP-fortified test meals of rice-lentils (khitchri) and EZP. Nineteen infants per group completed the first metabolic studies; 14 and 17 infants in MNP and MNP+Zn groups, completed the follow-up studies. Mean (±SD) AZs were 0.1± 0.1 and 1.2±0.5 mg at the first point for the MNP and MNP+Zn groups, respectively (p <0.001); results were nearly identical at the follow-up measurement. EZP did not differ between groups at the first measurement but was less in the MNP group (3.7±0.6 mg/kg) than in the MNP+Zn group (4.5±1.0 mg/kg) at the second measurement (P = 0.01). These data confirm that the MNP+Zn in khitchri were well absorbed, and after a year of home fortification, zinc status assessed by EZP was significantly better for the MNP+Zn group. Additional field studies may be necessary to ascertain the adequacy of this dose for infants at high risk of deficiency. (author)

Effect of irrigation water salinity and zinc application on yield, yield components and zinc accumulation of wheat

Directory of Open Access Journals (Sweden)

mohamad ahmadi

2009-06-01

Full Text Available Salinity stress is one of the most important problems of agriculture in crop production in arid and semi arid regions. Under these conditions, in addition to management strategies, proper and adequate nutrition also has an important role in crop improvement. A greenhouse experiment was conducted to study the effect of 4 different irrigation water salinities (blank, 4, 8 and 12 dS m-1, prepared with 1:1 molar ratio of chlorides of calcium and sodium and magnesium sulphate salts. and 5 different zinc applications (0, 10, 20, 30 mg Kg-1 soil and foliar application of salt of zinc sulphate on yield, yield components and zinc concentration of wheat, using a completely randomized design, factorial with three replications. Plant height, spike length, 1000 grain weight, number of grain per spike, grain and straw yield was decreased by Irrigation water salinity. And all of these parameters were improved by zinc application except 1000 grain weight. Zinc absorption and concentration in straw and grain was decreased by Saline water compared to blank. And concentration of zinc significantly was increased in straw and grain by increase zinc application. The results indicated that, zinc application under low to medium salinity conditions improved growth and yield of wheat due to decreasing the impacts salinity.

Zinc Status of Vegetarians during Pregnancy: A Systematic Review of Observational Studies and Meta-Analysis of Zinc Intake

Directory of Open Access Journals (Sweden)

Meika Foster

2015-06-01

Full Text Available Pregnant women are vulnerable to a low zinc status due to the additional zinc demands associated with pregnancy and foetal development. The present systematic review explores the relationship between habitual vegetarian diets and dietary zinc intake/status during pregnancy. The association between vegetarian diets and functional pregnancy outcome also is considered. A literature search was conducted of MEDLINE; PubMed; Embase; the Cochrane Library; Web of Science; and Scopus electronic databases up to September 2014. Six English-language observational studies qualified for inclusion in the systematic review. A meta-analysis was conducted that compared the dietary zinc intake of pregnant vegetarian and non-vegetarian (NV groups; the zinc intake of vegetarians was found to be lower than that of NV (−1.38 ± 0.35 mg/day; p < 0.001; and the exclusion of low meat eaters from the analysis revealed a greater difference (−1.53 ± 0.44 mg/day; p = 0.001. Neither vegetarian nor NV groups met the recommended dietary allowance (RDA for zinc. In a qualitative synthesis; no differences were found between groups in serum/plasma zinc or in functional outcomes associated with pregnancy. In conclusion; pregnant vegetarian women have lower zinc intakes than NV control populations and both groups consume lower than recommended amounts. Further information is needed to determine whether physiologic adaptations in zinc metabolism are sufficient to meet maternal and foetal requirements during pregnancy on a low zinc diet.

Zinc Deficiency in Latin America and the Caribbean.

Science.gov (United States)

Cediel, Gustavo; Olivares, Manuel; Brito, Alex; Cori, Héctor; López de Romaña, Daniel

2015-06-01

Zinc deficiency affects multiple vital functions in the life cycle, especially growth. Limited information is available on the magnitude of zinc deficiency in Latin America and the Caribbean. To examine the latest available information on both the prevalence of zinc deficiency and the risk of zinc deficiency in Latin America and the Caribbean. The prevalence of zinc deficiency was identified through a systematic review looking for the latest available data on serum zinc concentrations from surveys or studies with national representativeness conducted in Latin America and the Caribbean. The risk of zinc deficiency in Latin America and the Caribbean was estimated based on dietary zinc inadequacy (according to the 2011 National Food Balance Sheets) and stunting in children under 5 years of age. Only four countries had available national biochemical data. Mexican, Colombian, Ecuadorian, and Guatemalan children under 6 years of age and women 12 to 49 years of age had a high prevalence of zinc deficiency (19.1% to 56.3%). The countries with the highest risk of zinc deficiency (estimated prevalence of inadequate zinc intake > 25% plus prevalence of stunting > 20%) were Belize, Bolivia, El Salvador, Guatemala, Haiti, Honduras, Nicaragua, and Saint Vincent and the Grenadines. Zinc dietary inadequacy was directly correlated with stunting (r = 0.64, p zinc deficiency in children under 6 years of age and women 12 to 49 years of age. High rates of both estimated zinc dietary inadequacy and stunting were also reported in most Latin America and Caribbean countries.

Zinc-enriched boutons in rat spinal cord

DEFF Research Database (Denmark)

Schrøder, H D; Danscher, G; Jo, S M

2000-01-01

The rat spinal cord reveals a complex pattern of zinc-enriched (ZEN) boutons. As a result of in vivo exposure to selenide ions, nanosized clusters of zinc selenide are created in places where zinc ions are present, including the zinc-containing synaptic vesicles of ZEN boutons. The clusters can...

Estimating the global prevalence of zinc deficiency: results based on zinc availability in national food supplies and the prevalence of stunting.

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K Ryan Wessells

Full Text Available BACKGROUND: Adequate zinc nutrition is essential for adequate growth, immunocompetence and neurobehavioral development, but limited information on population zinc status hinders the expansion of interventions to control zinc deficiency. The present analyses were conducted to: (1 estimate the country-specific prevalence of inadequate zinc intake; and (2 investigate relationships between country-specific estimated prevalence of dietary zinc inadequacy and dietary patterns and stunting prevalence. METHODOLOGY AND PRINCIPAL FINDINGS: National food balance sheet data were obtained from the Food and Agriculture Organization of the United Nations. Country-specific estimated prevalence of inadequate zinc intake were calculated based on the estimated absorbable zinc content of the national food supply, International Zinc Nutrition Consultative Group estimated physiological requirements for absorbed zinc, and demographic data obtained from United Nations estimates. Stunting data were obtained from a recent systematic analysis based on World Health Organization growth standards. An estimated 17.3% of the world's population is at risk of inadequate zinc intake. Country-specific estimated prevalence of inadequate zinc intake was negatively correlated with the total energy and zinc contents of the national food supply and the percent of zinc obtained from animal source foods, and positively correlated with the phytate: zinc molar ratio of the food supply. The estimated prevalence of inadequate zinc intake was correlated with the prevalence of stunting (low height-for-age in children under five years of age (r = 0.48, P<0.001. CONCLUSIONS AND SIGNIFICANCE: These results, which indicate that inadequate dietary zinc intake may be fairly common, particularly in Sub-Saharan Africa and South Asia, allow inter-country comparisons regarding the relative likelihood of zinc deficiency as a public health problem. Data from these analyses should be used to determine

Prediction of Serum Zinc Levels in Mexican Children at 2 Years of Age Using a Food Frequency Questionnaire and Different Zinc Bioavailability Criteria.

Science.gov (United States)

Cantoral, Alejandra; Téllez-Rojo, Martha; Shamah-Levy, Teresa; Schnaas, Lourdes; Hernández-Ávila, Mauricio; Peterson, Karen E; Ettinger, Adrienne S

2015-06-01

The 2006 Mexican National Health and Nutrition Survey documented a prevalence of zinc deficiency of almost 30% in children under 2 years of age. We sought to validate a food frequency questionnaire (FFQ) for quantifying dietary bioavailable zinc intake in 2-year-old Mexican children accounting for phytic acid intake and using serum zinc as a reference. This cross-sectional study was nested within a longitudinal birth cohort of 333 young children in Mexico City. Nonfasting serum zinc concentration was measured and dietary zinc intake was calculated on the basis of a semiquantitative FFQ administered to their mothers. The relationship between dietary zinc intake and serum zinc was assessed using linear regression, adjusting for phytic acid intake, and analyzed according to two distinct international criteria to estimate bioavailable zinc. Models were stratified by zinc deficiency status. Dietary zinc, adjusted for phytic acid intake, explained the greatest proportion of the variance of serum zinc. For each milligram of dietary zinc intake, serum zinc increased on average by 0.95 μg/dL (0.15 μmol/L) (p = .06). When stratified by zinc status, this increase was 0.74 μg/dL (p = .12) for each milligram of zinc consumed among children with adequate serum zinc (n = 276), whereas among those children with zinc deficiency (n = 57), serum zinc increased by only 0.11 μg/dL (p = .82). A semiquantitative FFQ can be used for predicting serum zinc in relation to dietary intake in young children, particularly among those who are zinc-replete, and when phytic acid or phytate intake is considered. Future studies should be conducted accounting for both zinc status and dietary zinc inhibitors to further elucidate and validate these findings. © The Author(s) 2015.

From zinc selenate to zinc selenide nano structures synthesized by reduction process

International Nuclear Information System (INIS)

Hutagalung, S.D.; Eng, S.T.; Ahmad, Z.A.; Ishak Mat; Yussof Wahab

2009-01-01

One-dimensional nano structure materials are very attractive because of their electronic and optical properties depending on their size. It is well known that properties of material can be tuned by reducing size to nano scale because at the small sizes, that they behave differently with its bulk materials and the band gap will control by the size. The tunability of the band gap makes nano structured materials useful for many applications. As one of the wide band gaps semiconductor compounds, zinc selenide (ZnSe) nano structures (nanoparticles, nano wires, nano rods) have received much attention for the application in optoelectronic devices, such as blue laser diode, light emitting diodes, solar cells and IR optical windows. In this study, ZnSe nano structures have been synthesized by reduction process of zinc selenate using hydrazine hydrate (N 2 H 4 .2H 2 O). The reductive agent of hydrazine hydrate was added to the starting materials of zinc selenate were heat treated at 500 degree Celsius for 1 hour under argon flow to form one-dimensional nano structures. The SEM and TEM images show the formation of nano composite-like structure, which some small nano bar and nano pellets stick to the rod. The x-ray diffraction and elemental composition analysis confirm the formation of mixture zinc oxide and zinc selenide phases. (author)

Zinc and the modulation of redox homeostasis

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Oteiza, Patricia I.

2012-01-01

Zinc, a redox inactive metal, has been long viewed as a component of the antioxidant network, and growing evidence points to its involvement in redox-regulated signaling. These actions are exerted through several mechanisms based on the unique chemical and functional properties of zinc. Overall, zinc contributes to maintain the cell redox balance through different mechanisms including: i) the regulation of oxidant production and metal-induced oxidative damage; ii) the dynamic association of zinc with sulfur in protein cysteine clusters, from which the metal can be released by nitric oxide, peroxides, oxidized glutathione and other thiol oxidant species; iii) zinc-mediated induction of the zinc-binding protein metallothionein, which releases the metal under oxidative conditions and act per se scavenging oxidants; iv) the involvement of zinc in the regulation of glutathione metabolism and of the overall protein thiol redox status; and v) a direct or indirect regulation of redox signaling. Findings of oxidative stress, altered redox signaling, and associated cell/tissue disfunction in cell and animal models of zinc deficiency, stress the relevant role of zinc in the preservation of cell redox homeostasis. However, while the participation of zinc in antioxidant protection, redox sensing, and redox-regulated signaling is accepted, the involved molecules, targets and mechanisms are still partially known and the subject of active research. PMID:22960578

Caracterización microestructural de aleaciones base cobre obtenidas mediante molienda reactiva

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Palma, R.

2010-06-01

Full Text Available The micro and nanostructure of Cu-Al, Cu-V and Cu-Ti alloys produced by reactive milling were analyzed using X-ray diffraction (XRD and transmission electron microscopy (TEM. Samples with different milling times (t= 0, 10, 20 and 30 h were considered. The grain size, dislocation density and residual microstrain were evaluated form the XRD data using the Williamson-Hall and Klug-Alexander methods. The evolution of texture as a function of milling time was also studied using XRD. It was found, using TEM, that the grain size and dispersoid size were nanometric in all three alloys considered.

Se analizó la micro y nano estructura de aleaciones Cu-Al, Cu-V y Cu-Ti obtenidas por molienda reactiva, mediante difracción de rayos X (XRD y microscopía electrónica de transmisión (TEM. Se consideraron muestras con distintos tiempos de molienda (t= 0, 10, 20 y 30 h. A partir de los datos XRD, usando los métodos de Williamson- Hall y Klug-Alexander, se evaluaron el tamaño de grano, la densidad de dislocaciones y la microdeformación residual; también se estudió la evolución de la textura de la matriz de cobre en función del tiempo de molienda. En los polvos molidos durante 30 h, de las tres aleaciones consideradas, se encontró, por TEM, que los tamaños de grano y de los dispersoides desarrollados son nanométricos.

Expression of zinc transporter genes in rice as influenced by zinc-solubilizing Enterobacter cloacae strain ZSB14

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Selvaraj eKrithika

2016-04-01

Full Text Available Zinc (Zn deficiency in major food crops has been considered as an important factor affecting the crop production and subsequently the human health. Rice (Oryza sativa is sensitive to Zn deficiency and thereby causes malnutrition to most of the rice-eating Asian populations. Application of zinc solubilizing bacteria (ZSB could be a sustainable agronomic approach to increase the soil available Zn which can mitigate the yield loss and consequently the nutritional quality of rice. Understanding the molecular interactions between rice and unexplored ZSB is useful for overcoming Zn deficiency problems. In the present study, the role of zinc solubilizing bacterial strain Enterobacter cloacae strain ZSB14 on regulation of Zn-regulated transporters and iron (Fe-regulated transporter-like protein (ZIP genes in rice under iron sufficient and deficient conditions was assessed by quantitative real-time reverse transcription PCR. The expression patterns of OsZIP1, OsZIP4 and OsZIP5 in root and shoot of rice were altered due to the Zn availability as dictated by Zn sources and ZSB inoculation. Fe sufficiency significantly reduced the root and shoot OsZIP1 expression, but not the OsZIP4 and OsZIP5 levels. Zinc oxide in the growth medium up-regulated all the assessed ZIP genes in root and shoot of rice seedlings. When ZSB was inoculated to rice seedlings grown with insoluble zinc oxide in the growth medium, the expression of root and shoot OsZIP1, OsZIP4 and OsZIP5 was reduced. In the absence of zinc oxide, ZSB inoculation up-regulated OsZIP1 and OsZIP5 expressions. Zinc nutrition provided to the rice seedling through ZSB-bound zinc oxide solubilization was comparable to the soluble zinc sulphate application which was evident through the ZIP genes’ expression and the Zn accumulation in root and shoot of rice seedlings. These results demonstrate that zinc solubilizing bacteria could play a crucial role in zinc fertilization and fortification of rice.

Effect of gypsum, pressmud, fulvic acid and zinc sources on yield and zinc uptake by rice crop in a saline-sodic soil

International Nuclear Information System (INIS)

Chand, M.

1980-01-01

The application of fulvic acid to a saline-sodic soil augmented the solubility of zinc by thousands fold. Zinc fulvate when applied at levels equivalent to that of zinc sulphate was more effective in enhancing diffusion of zinc in the soil. Application of gypsum, zinc sulphate and fulvic acid significantly increased dry matter yield and uptake of zinc by rice crop in a saline-sodic soil. Application of gypsum with pressmud or with fulvic acid and zinc sulphate resulted in significantly higher yield and zinc uptake than in other treatments. (orig.)

Zinc Binding by Lactic Acid Bacteria

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Jasna Mrvčić

2009-01-01

Full Text Available Zinc is an essential trace element in all organisms. A common method for the prevention of zinc deficiency is pharmacological supplementation, especially in a highly available form of a metalloprotein complex. The potential of different microbes to bind essential and toxic heavy metals has recently been recognized. In this work, biosorption of zinc by lactic acid bacteria (LAB has been investigated. Specific LAB were assessed for their ability to bind zinc from a water solution. Significant amount of zinc ions was bound, and this binding was found to be LAB species-specific. Differences among the species in binding performance at a concentration range between 10–90 mg/L were evaluated with Langmuir model for biosorption. Binding of zinc was a fast process, strongly influenced by ionic strength, pH, biomass concentration, and temperature. The most effective metal-binding LAB species was Leuconostoc mesenteroides (27.10 mg of Zn2+ per gram of dry mass bound at pH=5 and 32 °C, during 24 h. FT-IR spectroscopy analysis and electron microscopy demonstrated that passive adsorption and active uptake of the zinc ions were involved.

Pseudomonas aeruginosa Trent and zinc homeostasis.

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Davies, Corey B; Harrison, Mark D; Huygens, Flavia

2017-09-01

Pseudomonas aeruginosa is a Gram-negative pathogen and the major cause of mortality in patients with cystic fibrosis. The mechanisms that P. aeruginosa strains use to regulate intracellular zinc have an effect on infection, antibiotic resistance and the propensity to form biofilms. However, zinc homeostasis in P. aeruginosa strains of variable infectivity has not been compared. In this study, zinc homeostasis in P. aeruginosa Trent, a highly infectious clinical strain, was compared to that of a laboratory P. aeruginosa strain, ATCC27853. Trent was able to tolerate higher concentrations of additional zinc in rich media than ATCC27853. Further, pre-adaptation to additional zinc enhanced the growth of Trent at non-inhibitory concentrations but the impact of pre-adaption on the growth of ATCC27853 under the same conditions was minimal. The results establish clear differences in zinc-induced responses in Trent and ATCC27853, and how zinc homeostasis can be a promising target for the development of novel antimicrobial strategies for P. aeruginosa infection in cystic fibrosis patients. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Changes in zinc status and zinc transporters expression in whole blood of patients with Systemic Inflammatory Response Syndrome (SIRS).

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Florea, Daniela; Molina-López, Jorge; Hogstrand, Christer; Lengyel, Imre; de la Cruz, Antonio Pérez; Rodríguez-Elvira, Manuel; Planells, Elena

2018-09-01

Critically ill patients develop severe stress, inflammation and a clinical state that may raise the utilization and metabolic replacement of many nutrients and especially zinc, depleting their body reserves. This study was designed to assess the zinc status in critical care patients with systemic inflammatory response syndrome (SIRS), comparing them with a group of healthy people, and studying the association with expression of zinc transporters. This investigation was a prospective, multicentre, comparative, observational and analytic study. Twelve critically ill patients from different hospitals and 12 healthy subjects from Granada, Spain, all with informed consent were recruited. Data on daily nutritional assessment, ICU severity scores, inflammation, clinical and nutritional parameters, plasma and blood cell zinc concentrations, and levels of transcripts for zinc transporters in whole blood were taken at admission and at the seventh day of the ICU stay. Zinc levels on critical ill patient are diminish comparing with the healthy control (HS: 0.94 ± 0.19; CIPF: 0.67 ± 0.16 mg/dL). The 58% of critical ill patients showed zinc plasma deficiency at beginning of study while 50.0% of critical ill after 7 days of ICU stay. ZnT7, ZIP4 and ZIP9 were the zinc transporters with highest expression in whole blood. In general, all zinc transporters were significantly down-regulated (P < 0.05) in the critical ill population at admission in comparison with healthy subjects. Severity scores and inflammation were significantly associated (P < 0.05) with zinc plasma levels, and zinc transporters ZIP3, ZIP4, ZIP8, ZnT6, ZnT7. Expression of 11 out of 24 zinc transporters was analysed, and ZnT1, ZnT4, ZnT5 and ZIP4, which were downregulated by more than 3-fold in whole blood of patients. In summary, in our study an alteration of zinc status was related with the severity-of-illness scores and inflammation in critical ill patients since admission in ICU stay. SIRS

Maternal Zinc Intakes and Homeostatic Adjustments during Pregnancy and Lactation

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Donangelo, Carmen Marino; King, Janet C.

2012-01-01

Zinc plays critical roles during embryogenesis, fetal growth, and milk secretion, which increase the zinc need for pregnancy and lactation. Increased needs can be met by increasing the dietary zinc intake, along with making homeostatic adjustments in zinc utilization. Potential homeostatic adjustments include changes in circulating zinc, increased zinc absorption, decreased zinc losses, and changes in whole body zinc kinetics. Although severe zinc deficiency during pregnancy has devastating effects, systematic reviews and meta-analysis of the effect of maternal zinc supplementation on pregnancy outcomes have consistently shown a limited benefit. We hypothesize, therefore, that zinc homeostatic adjustments during pregnancy and lactation improve zinc utilization sufficiently to provide the increased zinc needs in these stages and, therefore, mitigate immediate detrimental effects due to a low zinc intake. The specific questions addressed are the following: How is zinc utilization altered during pregnancy and lactation? Are those homeostatic adjustments influenced by maternal zinc status, dietary zinc, or zinc supplementation? These questions are addressed by critically reviewing results from published human studies on zinc homeostasis during pregnancy and lactation carried out in different populations worldwide. PMID:22852063

Vacuolar zinc transporter Zrc1 is required for detoxification of excess intracellular zinc in the human fungal pathogen Cryptococcus neoformans.

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Cho, Minsu; Hu, Guanggan; Caza, Mélissa; Horianopoulos, Linda C; Kronstad, James W; Jung, Won Hee

2018-01-01

Zinc is an important transition metal in all living organisms and is required for numerous biological processes. However, excess zinc can also be toxic to cells and cause cellular stress. In the model fungus Saccharomyces cerevisiae, a vacuolar zinc transporter, Zrc1, plays important roles in the storage and detoxification of excess intracellular zinc to protect the cell. In this study, we identified an ortholog of the S. cerevisiae ZRC1 gene in the human fungal pathogen Cryptococcus neoformans. Zrc1 was localized in the vacuolar membrane in C. neoformans, and a mutant lacking ZRC1 showed significant growth defects under high-zinc conditions. These results suggested a role for Zrc1 in zinc detoxification. However, contrary to our expectation, the expression of Zrc1 was induced in cells grown in zinc-limited conditions and decreased upon the addition of zinc. These expression patterns were similar to those of Zip1, the high-affinity zinc transporter in the plasma membrane of C. neoformans. Furthermore, we used the zrc1 mutant in a murine model of cryptococcosis to examine whether a mammalian host could inhibit the survival of C. neoformans using zinc toxicity. We found that the mutant showed no difference in virulence compared with the wildtype strain. This result suggests that Zrc1-mediated zinc detoxification is not required for the virulence of C. neoformans, and imply that zinc toxicity may not be an important aspect of the host immune response to the fungus.

Coating compositions comprising bismuth-alloyed zinc

DEFF Research Database (Denmark)

2008-01-01

The present application discloses (i) a coating composition comprising a particulate zinc-based alloyed material, said material comprising 0.05-0.7% by weight of bismuth (Bi), the D50 of the particulate material being in the range of 2.5-30 µm; (ii) a coated structure comprising a metal structure...... having a first coating of the zinc-containing coating composition applied onto at least a part of the metal structure in a dry film thickness of 5-100 µm; and an outer coating applied onto said zinc-containing coating in a dry film thickness of 30-200 µm; (iii) a particulate zinc-based alloyed material......, wherein the material comprises 0.05-0.7%(w/w) of bismuth (Bi), and wherein the D50 of the particulate material is in the range of 2.5-30 µm; (iv) a composite powder consisting of at least 25%(w/w) of the particulate zinc-based alloyed material, the rest being a particulate material consisting of zinc...

Anti-corrosive Effects of Multi-Walled Carbon Nano Tube and Zinc Particle Shapes on Zinc Ethyl Silicate Coated Carbon Steel

Energy Technology Data Exchange (ETDEWEB)

Jang, JiMan; Shon, MinYoung; Kwak, SamTak [Pukyong National University, Busan (Korea, Republic of)

2016-01-15

Zinc ethyl silicate coatings containing multi walled carbon nanotubes (MWCNTs) were prepared, to which we added spherical and flake shaped zinc particles. The anti-corrosive effects of MWCNTs and zinc shapes on the zinc ethyl silicate coated carbon steel was examined, using electrochemical impedance spectroscopy and corrosion potential measurement. The results of EIS and corrosion potential measurement showed that the zinc ethyl silicate coated with flake shaped zinc particles and MWCNT showed lesser protection to corrosion. These outcomes were in agreement with previous results of corrosion potential and corrosion occurrence.

Serum zinc, copper, retinol-binding protein, prealbumin, and ceruloplasmin concentrations in infants receiving intravenous zinc and copper supplementation.

Science.gov (United States)

Lockitch, G; Godolphin, W; Pendray, M R; Riddell, D; Quigley, G

1983-02-01

One hundred twenty-seven newborn infants requiring parenteral nutrition were randomly assigned to receive differing amounts of zinc (40 to 400 micrograms/kg/day) and copper (20 or 40 micrograms/kg/day) supplementation within five birth weight groups (600 to 2,500 gm). The serum zinc concentration remained relatively constant in the group receiving the most zinc supplementation after two weeks of therapy, but declined sharply in the groups receiving less supplementation. No effect of increased copper intake was noted on ceruloplasmin values, but a difference in serum copper concentrations was noted at two weeks. No correlation was noted between serum zinc and copper values or among those for serum zinc, retinol-binding protein, and prealbumin. Reference ranges were defined for serum zinc, copper, retinol-binding protein, prealbumin, and ceruloplasmin in the preterm infant.

Fear-of-intimacy-mediated zinc transport controls the function of zinc-finger transcription factors involved in myogenesis.

Science.gov (United States)

Carrasco-Rando, Marta; Atienza-Manuel, Alexandra; Martín, Paloma; Burke, Richard; Ruiz-Gómez, Mar

2016-06-01

Zinc is a component of one-tenth of all human proteins. Its cellular concentration is tightly regulated because its dyshomeostasis has catastrophic health consequences. Two families of zinc transporters control zinc homeostasis in organisms, but there is little information about their specific developmental roles. We show that the ZIP transporter Fear-of-intimacy (Foi) is necessary for the formation of Drosophila muscles. In foi mutants, myoblasts segregate normally, but their specification is affected, leading to the formation of a misshapen muscle pattern and distorted midgut. The observed phenotypes could be ascribed to the inactivation of specific zinc-finger transcription factors (ZFTFs), supporting the hypothesis that they are a consequence of intracellular depletion of zinc. Accordingly, foi phenotypes can be rescued by mesodermal expression of other ZIP members with similar subcellular localization. We propose that Foi acts mostly as a transporter to regulate zinc intracellular homeostasis, thereby impacting on the activity of ZFTFs that control specific developmental processes. Our results additionally suggest a possible explanation for the presence of large numbers of zinc transporters in organisms based on differences in ion transport specificity and/or degrees of activity among transporters. © 2016. Published by The Company of Biologists Ltd.

Aplicación terapéutica de la ionización al cobre en el tratamiento de las ulceraciones genitales en el hombre

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Luis M. Salgar

1940-06-01

medio de una corriente eléctrica directa o continua. La cantidad de droga introducida está en proporción directa con la intensidad de la corriente y el tiempo que dure el electrodo en contacto con los tejidos. Un tratamiento prolongado con un pequeño amperaje hará penetrar más profundamente los iones que un tratamiento corto y de alto amperaje. Entre mayor sea la superficie de contacto con el electrodo activo mayor será la cantidad de corriente. Se considera que con un electrodo regular y la aplicación de diez miliamperios durante veinte minutos (200 miliamperios minuto, pueden penetrar los iones de cobre casi 8 milímetros en los tejidos enfermos.

The relative contribution of natural zinc complexing agents and ZnSO4 to growth and zinc nutrition of maize

International Nuclear Information System (INIS)

Kumar, M.; Prasad, B.

1989-01-01

Relative evaluation of different natural zinc-complexes indicated that application of Zn-FA 2 (PM), Zn-FA 3 (Comp), Zn-FA 1 (BGS), Zn-FA 5 (PR), Zn-FA 4 (SS) and ZnSO 4 significantly enhanced the drymatter yield and zinc uptake by maize. The natural zinc-complexes in particular increased, to a greater extent, the uptake of both native and applied sources than that observed with ZnSO 4 as zinc carrier. Significant positive relationship between self-diffusion coefficient of Zn and drymatter yield and uptake of zinc by maize suggested that diffusion is responsible for the supply of zinc from ambient soil matrix to plant roots. (author). 12 refs., 5 tabs

Study of iron-zinc catalysts by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Arriola, S.H.

1990-01-01

The Moessbauer parameters were determined on a series of catalyst mixtures of iron and zinc oxides with variable quantities of zinc. A change in the crystal structure of the iron oxide when introducing zinc into the samples was observed. The corundum structure of the α-Fe 2 O 3 phase was transformed into the spinel type of zinc ferrite when zinc oxide was present in any quantity. A strong electronic interaction between the zinc ferrite and the zinc oxide present in excess was evident. The catalysts were analyzed using x-ray fluorescence and x-ray diffraction methods. (author) 10 refs.; 4 figs.; 2 tabs

Zinc Finger Takes on a Whole New Meaning: Reducing and Monitoring Zinc Blanks in the Isotope Lab

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Wilkes, E. B.; Wasylenki, L. E.; Anbar, A. D.

2010-12-01

In terms of avoiding contamination, zinc is one of the most difficult elements to study isotopically. The reason for this is that zinc stearate is a very common mold release agent in the production of plastics, including those most often used in isotope geochemistry clean labs. While polyethylene bottles, polypropylene centrifuge tubes, pipette tips, and Kimwipes are all potential sources of contaminant zinc, by far the largest amount of zinc is introduced to the laboratory by gloves. Most items can be effectively rid of zinc by soaking in dilute hydrochloric acid, but gloves cannot be cleaned easily, and use of gloves can quickly lead to contamination on many surfaces throughout the lab. We recently conducted several experiments in which dissolved zinc was partly adsorbed onto synthetic Mn oxyhydroxide particles. The dissolved and adsorbed pools were separated by filtration, purified with ion exchange chemistry, and analyzed for isotope composition by MC-ICP-MS. We used a commercially purchased ICP standard solution both as our standard (delta66/64Zn = 0) and as the source of the zinc in the experiments. Whenever gloves were worn during purification, process blanks contained as much as 150 ng Zn, and both the dissolved and adsorbed pools of zinc came out enriched in heavy isotopes relative to the starting pool, contrary to our expectation of mass balance. When gloves were not worn, blanks were brands of vinyl gloves, including one brand recommended to us for being “low” in zinc, measured +10‰ relative to our standard. We therefore concluded that glove zinc contaminated most of our experimental samples. We were only able to see such clear evidence of contamination because (1) we were doing an experiment in which we expected one light and one heavy pool of zinc compared to our standard, and (2) we happened to use an ICP standard solution for delta = 0 that is strongly enriched in light isotopes relative to both brands of gloves. We caution others who measure

21 CFR 582.5985 - Zinc chloride.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Zinc chloride. 582.5985 Section 582.5985 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5985 Zinc chloride. (a) Product. Zinc chloride. (b) Conditions of use. This substance is...

21 CFR 182.8985 - Zinc chloride.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Zinc chloride. 182.8985 Section 182.8985 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8985 Zinc chloride. (a) Product. Zinc chloride. (b) Conditions of use. This substance is generally recognized as safe when used in...

Uptake and loss of dissolved zinc by the stickleback gasterosteus Aculeatus l. [Zinc 65

Energy Technology Data Exchange (ETDEWEB)

Matthiessen, P.; Brafield, A.E.

1977-01-01

Uptake and loss by sticklebacks of both stable zinc and /sup 65/Zn in hard and soft water were studied for periods up to 400 h. In calcium-free water, the zinc uptake curve is approximately asymptotic over a period of 24 h, while in hard water internal Zn levels dropped at 24 h. Over 5 h, fish in hard tapwater absorb about 3 to 5 times more Zn than those in calcium-free water. There is positive linear correlation between log Zn uptake and log wet weight of fish. Whole-body concentration factors (c.f.) at 16 h reach a maximum of 12.2 (mean = 2.9), highest concentrations of Zn being found in the gills (mean c.f. = 5.1), and lowest concentrations in the gonads (mean c.f. = 0.8). Over longer periods (400 h), internal stable zinc levels of fish exposed to 1 and 4 ppM Zn/sup +2/ remain little higher than controls (max. 28%) /sup 65/Zn efflux in zinc-free water falls to zero after 5 h, more zinc (78%) being lost after uptake in tapwater than in calcium-free water (56%).

Zinc Enolate/Sulfinate Prepared from a Single-Run Reaction Using Zinc Dust with O-Tosylated 4-Hydroxy Coumarin and Pyrone

Energy Technology Data Exchange (ETDEWEB)

Shin, Ueon Sang; Joo, Seong-Ryu; Kim, Seung-Hoi [Dankook University, Cheonan (Korea, Republic of)

2016-07-15

We demonstrated the preparation of new zinc complexes, 2-oxo-2H-chromen-4-yloxy tosylzinc (I), and 6-methyl-2-oxo-2H-pyran-4-yloxy tosylzinc (II), by the oxidative addition of readily available zinc dust into the corresponding 4-tosylated coumarin (A) and pyrone (B), respectively. Of special interest, the thus-obtained zinc complexes showed an electrophile-dependent reactivity. The subsequent coupling reactions of I and II with a variety of acid chlorides provided the O-acylation product in moderate yields. More interestingly, it should be emphasized that the thus-prepared zinc complexes (I and II) functioned both as zinc enolate and zinc sulfinate, providing C(3)-disubstituted product (b) and sulfone (c), respectively, from a single-run reaction when I or II was treated with benzyl halides. Even though somewhat low yields were achieved under the nonoptimized conditions, the novel zinc complexes present another potential application for zinc reagents. Versatile applications of this discovery are currently underway.

Zinc Enolate/Sulfinate Prepared from a Single-Run Reaction Using Zinc Dust with O-Tosylated 4-Hydroxy Coumarin and Pyrone

International Nuclear Information System (INIS)

Shin, Ueon Sang; Joo, Seong-Ryu; Kim, Seung-Hoi

2016-01-01

We demonstrated the preparation of new zinc complexes, 2-oxo-2H-chromen-4-yloxy tosylzinc (I), and 6-methyl-2-oxo-2H-pyran-4-yloxy tosylzinc (II), by the oxidative addition of readily available zinc dust into the corresponding 4-tosylated coumarin (A) and pyrone (B), respectively. Of special interest, the thus-obtained zinc complexes showed an electrophile-dependent reactivity. The subsequent coupling reactions of I and II with a variety of acid chlorides provided the O-acylation product in moderate yields. More interestingly, it should be emphasized that the thus-prepared zinc complexes (I and II) functioned both as zinc enolate and zinc sulfinate, providing C(3)-disubstituted product (b) and sulfone (c), respectively, from a single-run reaction when I or II was treated with benzyl halides. Even though somewhat low yields were achieved under the nonoptimized conditions, the novel zinc complexes present another potential application for zinc reagents. Versatile applications of this discovery are currently underway

Radioisotopic investigations of zinc uptake into brain slices

International Nuclear Information System (INIS)

Howell, G.A.

1983-01-01

The presence of zinc in the vicinity of the hippocampal mossy fibers has been repeatedly demonstrated, and several lines of evidence suggest that the mossy-fiber zinc is concentrated within the terminals of mossy fibers. In search of insight into the metabolism and function of mossy-fiber zinc, the present study investigated the transport of zinc into tissue slices and the response of the zinc transport to depolarization. Kinetic analysis of zinc accumulation by mouse brain slices in vitro revealed the presence of a high affinity uptake component with an apparent Km of 17.7 μM for hippocampus, 16.6 μM< for cortex and 25 μM for striatum and a V/sub max/ of 9.2 ng/mg/hr for the hippocampus, 10.1 ng/mg/hr for cortex and 9.6 ng/mg/hr for striatum. Cytoarchitectonic differences in zinc transport between the different hippocampal subregions were found with those regions containing granule cells or mossy fiber axons accumulating greater amounts of zinc than the CA 1 region. The present finding that mossy-fiber neuropil selectivity accumulates zinc suggests the presence of a zinc-binding substance unique to mossy-fiber tissue

Daya antibakteri penambahan Propolis pada zinc oxide eugenol dan zinc oxide terhadap kuman campur gigi molar sulung non vital (The antibacterial effect of propolis additional to zinc oxide eugenol and zinc oxide on polybacteria of necrotic primary molar

Directory of Open Access Journals (Sweden)

Yemy Ameliana

2014-12-01

Full Text Available Background: Materials commonly used for root canal filling of primary teeth is zinc oxide eugenol. Eugenol has some disadvantages that can irritate the periapical tissues, has the risk of disturbing the growth and development of permanent tooth buds, and has a narrow antibacterial spectrum. Studies showed that propolis at concentration of 20 % has antibacterial activity against Staphylococcus aureus. Purpose: The purpose of this study was to examine the antimicrobial activity of root canal pastes with the additional of propolis additional to zinc oxide eugenol (ZOEP and to zinc oxide (ZOP. Methods: Polybacteria cultures collected from root canals of necrotic primary molar from 5 children patients who received root canal treatment. The bacteria were grown in BHI Broth, and inoculated into Muller Hinton Agar media. The agar plates was divided into 3 areas, and one well was made at each area. The first well filled with ZOE as a control, second well filled with ZOEP and the third well filled with ZOP, then incubated for 24 hour at 370 C. Antimicrobial activity was determined by measuring the diameters of inhibition zones of polybacteria growth. The data were statistically analyzed by independent T-test. Results: The pasta mixture of zinc oxide propolis had the strongest antibacterial activity against polybacteria of necrotic primary molar, followed by zinc oxide eugenol propolis paste, and zinc oxide eugenol paste. There were significant differences of inhibition zones between ZOE, ZOEP and ZOP (p<0,05. Conclusion: The study suggested that the additional of propolis to zinc oxide paste could increase the antimicrobial effect against root canal polybacteria of necrotic primary molar.Latar belakang: Bahan yang sering digunakan untuk pengisian saluran akar gigi sulung adalah zinc oxide eugenol. Eugenol memiliki beberapa kekurangan yaitu dapat mengiritasi jaringan periapikal, beresiko mengganggu pertumbuhan dan perkembangan benih gigi permanen pengganti

Maternal Zinc Intakes and Homeostatic Adjustments during Pregnancy and Lactation

OpenAIRE

Donangelo, Carmen Marino; King, Janet C.

2012-01-01

Zinc plays critical roles during embryogenesis, fetal growth, and milk secretion, which increase the zinc need for pregnancy and lactation. Increased needs can be met by increasing the dietary zinc intake, along with making homeostatic adjustments in zinc utilization. Potential homeostatic adjustments include changes in circulating zinc, increased zinc absorption, decreased zinc losses, and changes in whole body zinc kinetics. Although severe zinc deficiency during pregnancy has devastating e...

21 CFR 558.78 - Bacitracin zinc.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Bacitracin zinc. 558.78 Section 558.78 Food and... in Animal Feeds § 558.78 Bacitracin zinc. (a) Specifications. Type A medicated articles containing bacitracin zinc equivalent to 10, 25, 40, or 50 grams per pound bacitracin. (b) Approvals. See No. 046573 in...

Blood gas profile of copper-poisoned in sheep treated with ammonium tetrathiomolybdatePerfil de gases sanguíneos de ovinos intoxicados por cobre e tratados com tetratiomolibidato de amônio

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Maria Claudia Araripe Sucupira

2012-05-01

Full Text Available The aim of this study was to evaluate the blood gas profile of experimentally copper-poisoned sheep (in the pre-hemolytic, hemolytic and post-hemolytic phases that have been treated or not treated with ammonium tetrathiomolybdate. Ten lambs of the Santa Ines breed were divided into two groups: control and ATTM (treated (ammonium tetrathiomolibydate. The animals were submitted to increasing doses of copper sulfate until macroscopic hemoglobinuria was detected.All of the control animals from died within four days of hemolytic crisis, and one sheep from ATTM died during the treatment. There was no difference in blood gas parameters between experimental groups. Higher values of pCO2 were observed during the hemolytic crisis (HC in both groups. The control group had higher mean values of hCO3 in the times HC and 2 days after hemolytic crisis (dA when compared with the time 15 before hemolytic crises (dB. The sheep that were treated with ATTM presented lower values of hCO3 at 7dB and higher levels at the HC. The control and ATTM groups exhibited higher values of BE during the HC. Poisoning resulted in disorder in the acid-base equilibrium, characterized by metabolic alkalosis and respiratory acidosis. Treatment with ATTM was able to reverse the changes in acid-base balance in copper poisoning sheep. O objetivo desse estudo foi avaliar o perfil de gases sanguineos em ovinos experimentalmente intoxicados com cobre (fases: pré-hemoltica, hemolitica e pós-hemolitica tratados ou não com tetratiomolibidato de amônio (ATTM. Dez cordeiros da raça Santa Inês foram divididos em dois grupos:controle (tratados com solução fisiologica a 0,9% e ATTM (tratados com 3,4 mg/kg de tetratiomolibidato de amonio. Os animais foram submetidos a doses crescentes de sulfato de cobre até a observação de hemoglobinúria macroscópica. Todos os animais do grupo controle morreram dentro de quatro dias após observação da hemoglobinúria, e um cordeiro do grupo ATTM

The zinc dyshomeostasis hypothesis of Alzheimer's disease.

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Travis J A Craddock

Full Text Available Alzheimer's disease (AD is the most common form of dementia in the elderly. Hallmark AD neuropathology includes extracellular amyloid plaques composed largely of the amyloid-β protein (Aβ, intracellular neurofibrillary tangles (NFTs composed of hyper-phosphorylated microtubule-associated protein tau (MAP-tau, and microtubule destabilization. Early-onset autosomal dominant AD genes are associated with excessive Aβ accumulation, however cognitive impairment best correlates with NFTs and disrupted microtubules. The mechanisms linking Aβ and NFT pathologies in AD are unknown. Here, we propose that sequestration of zinc by Aβ-amyloid deposits (Aβ oligomers and plaques not only drives Aβ aggregation, but also disrupts zinc homeostasis in zinc-enriched brain regions important for memory and vulnerable to AD pathology, resulting in intra-neuronal zinc levels, which are either too low, or excessively high. To evaluate this hypothesis, we 1 used molecular modeling of zinc binding to the microtubule component protein tubulin, identifying specific, high-affinity zinc binding sites that influence side-to-side tubulin interaction, the sensitive link in microtubule polymerization and stability. We also 2 performed kinetic modeling showing zinc distribution in extra-neuronal Aβ deposits can reduce intra-neuronal zinc binding to microtubules, destabilizing microtubules. Finally, we 3 used metallomic imaging mass spectrometry (MIMS to show anatomically-localized and age-dependent zinc dyshomeostasis in specific brain regions of Tg2576 transgenic, mice, a model for AD. We found excess zinc in brain regions associated with memory processing and NFT pathology. Overall, we present a theoretical framework and support for a new theory of AD linking extra-neuronal Aβ amyloid to intra-neuronal NFTs and cognitive dysfunction. The connection, we propose, is based on β-amyloid-induced alterations in zinc ion concentration inside neurons affecting stability of

The zinc dyshomeostasis hypothesis of Alzheimer's disease.

Science.gov (United States)

Craddock, Travis J A; Tuszynski, Jack A; Chopra, Deepak; Casey, Noel; Goldstein, Lee E; Hameroff, Stuart R; Tanzi, Rudolph E

2012-01-01

Alzheimer's disease (AD) is the most common form of dementia in the elderly. Hallmark AD neuropathology includes extracellular amyloid plaques composed largely of the amyloid-β protein (Aβ), intracellular neurofibrillary tangles (NFTs) composed of hyper-phosphorylated microtubule-associated protein tau (MAP-tau), and microtubule destabilization. Early-onset autosomal dominant AD genes are associated with excessive Aβ accumulation, however cognitive impairment best correlates with NFTs and disrupted microtubules. The mechanisms linking Aβ and NFT pathologies in AD are unknown. Here, we propose that sequestration of zinc by Aβ-amyloid deposits (Aβ oligomers and plaques) not only drives Aβ aggregation, but also disrupts zinc homeostasis in zinc-enriched brain regions important for memory and vulnerable to AD pathology, resulting in intra-neuronal zinc levels, which are either too low, or excessively high. To evaluate this hypothesis, we 1) used molecular modeling of zinc binding to the microtubule component protein tubulin, identifying specific, high-affinity zinc binding sites that influence side-to-side tubulin interaction, the sensitive link in microtubule polymerization and stability. We also 2) performed kinetic modeling showing zinc distribution in extra-neuronal Aβ deposits can reduce intra-neuronal zinc binding to microtubules, destabilizing microtubules. Finally, we 3) used metallomic imaging mass spectrometry (MIMS) to show anatomically-localized and age-dependent zinc dyshomeostasis in specific brain regions of Tg2576 transgenic, mice, a model for AD. We found excess zinc in brain regions associated with memory processing and NFT pathology. Overall, we present a theoretical framework and support for a new theory of AD linking extra-neuronal Aβ amyloid to intra-neuronal NFTs and cognitive dysfunction. The connection, we propose, is based on β-amyloid-induced alterations in zinc ion concentration inside neurons affecting stability of polymerized

Activity incorporation into zinc doped PWR oxides

International Nuclear Information System (INIS)

Maekelae, Kari

1998-01-01

Activity incorporation into the oxide layers of PWR primary circuit constructional materials has been studied in Halden since 1993. The first zinc injection tests showed that zinc addition resulted in thinner oxide layers on new metal surfaces and reduced further incorporation of activity into already existing oxides. These tests were continued to find out the effects of previous zinc additions on the pickup of activity onto the surface oxides which were subsequently exposed to zinc-free coolant. The results showed that previous zinc addition will continue to reduce the rate of Co-60 build-up on out-of-core surfaces in subsequent exposure to zinc-free coolants. However, the previous Zn free test was performed for a relatively short period of time and the water chemistry programme was continued to find out the long term effects for extended periods without zinc. The activity incorporation into the stainless steel oxides started to increase as soon as zinc dosing to the coolant was stopped. The Co-60 concentration was lowest on all of the coupons which were first oxidised in Zn containing primary coolant. After the zinc injection period the thickness of the oxides increased, but activity in the oxide films did not increase at the same rate. This could indicate that zinc in the oxide blocks the adsorption sites for Co-60 incorporation. The Co-60 incorporation rate into the oxides on Inconel 600 seemed to be linear whether the oxide was pre-oxidised with or without Zn. The results indicate that zinc can either replace or prevent cobalt transport in the oxides. The results show that for zinc injection to be effective it should be carried out continuously. Furthermore the actual mechanism by which Zn inhibits the activity incorporation into the oxides is still not clear. Therefore, additional work has to follow with specified materials to verify the conclusions drawn in this work. (author)

Extraction of Zinc and Manganese from Alkaline and Zinc-Carbon Spent Batteries by Citric-Sulphuric Acid Solution

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Francesco Ferella

2010-01-01

Full Text Available The paper is focused on the recovery of zinc and manganese from alkaline and zinc-carbon spent batteries. Metals are extracted by sulphuric acid leaching in the presence of citric acid as reducing agent. Leaching tests are carried out according to a 24 full factorial design, and empirical equations for Mn and Zn extraction yields are determined from experimental data as a function of pulp density, sulphuric acid concentration, temperature, and citric acid concentration. The highest values experimentally observed for extraction yields were 97% of manganese and 100% of zinc, under the following operating conditions: temperature 40∘C, pulp density 20%, sulphuric acid concentration 1.8 M, and citric acid 40 g L-1. A second series of leaching tests is also performed to derive other empirical models to predict zinc and manganese extraction. Precipitation tests, aimed both at investigating precipitation of zinc during leaching and at evaluating recovery options of zinc and manganese, show that a quantitative precipitation of zinc can be reached but a coprecipitation of nearly 30% of manganese also takes place. The achieved results allow to propose a battery recycling process based on a countercurrent reducing leaching by citric acid in sulphuric solution.

Study of Doppler broadened annihilation spectra in zinc and zinc-containing 0.05 at. % iron

International Nuclear Information System (INIS)

Troev, T.; Zolov, R.; Dimova, V.; Levay, B.

1979-01-01

The Doppler broadening of annihilation gamma spectra obtained from positron-electron annihilation in pure polycrystalline zinc and zinc-containing 0.05 at. % iron have been investigated. The line shapes were measured by a Ge(Li) detector in coincidence with a NaI(Tl) scintillation detector. The results are quite consistent with those expected from the trapping model. The positrons are trapped by impurity atoms and vacancy-impurity pairs in zinc containing 0.05 at. % iron. (author)

EFECTO EN LA RESISTENCIA DE LAS ESCORIAS DE FUNDICIÓN DE COBRE COMO AGREGADO FINO EN EL COMPORTAMIENTO RESISTENTE DEL HORMIGÓN EFFECT OF SMELTING COPPER SLAG AS FINE AGGREGATE ON THE RESISTANT BEHAVIOR OF CONCRETE

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Patricio Cendoya

2009-04-01

Full Text Available Las escorias de fundición de cobre son residuos industriales provenientes de la fundición del cobre las cuales procesadas en forma de granallas y sometidas a un proceso de molienda adquieren características similares a las de un árido fino. La presente investigación estudia la influencia que tiene su incorporación en el comportamiento mecánico a flexotracción y compresión en hormigones que emplean como árido fino una combinación de arenas del río Bío-Bío con proporciones de 25%, 40% y 50% en volumen de escorias de fundición de cobre. El árido fino resultante se utiliza en la confección de hormigones dosificados para relaciones de agua cemento de 0,45 y 0,52 asociadas a resistencias especificadas a la flexotracción de 3,6 y 4,3 MPa. Se mide la trabajabilidad en el hormigón fresco, la densidad, la carga de rotura por flexotracción y la carga de rotura por compresión en el hormigón endurecido comparando los resultados con un hormigón de referencia que no contiene escorias. Los resultados señalan que la docilidad de la mezcla se incrementa debido a la textura lisa de las escorias, se produce un aumento de la densidad del hormigón endurecido y las resistencias tanto a flexotracción como compresión se incrementan en función del contenido de escorias de fundición de cobre utilizado en la mezcla.Copper slag is a by product of the copper smelting industry. We took granulated copper slag and milled it until it acquired characteristics similar to those of a fine aggregate, which was then incorporated into concrete, in combination with Bio-Bio river sand in proportions of 25%, 40% and 50% by volume of copper slag. We then examined the impact of the different combinations on the mechanical behaviour to flexotraction and compression in the resulting concrete. Our specification was to produce concrete for water-cement ratios of 0,45 and 0,52 associated to breakage resistances to flexotraction of 3.6 and 4.3 MPa, respectively. We

Zinc deficiency among a healthy population in Baghdad, Iraq

International Nuclear Information System (INIS)

Al-Timimi, D.; Al-Najjar, F.; Al-Sharbatti, Shatha S.

2005-01-01

To determine the prevalence of zinc deficiency and the current zinc status among a sample selected from the healthy population in Baghdad, Iraq. We carried out a community-based study in Baghdad City, Iraq from November through June 2002. We selected a sample of 2090 healthy subjects (aged 1 month to 85 years). We used a pre-tested questionnaire, designed to obtain information on gender, birth dates, height, weight, residence, habitual food consumption patterns, and social status. We performed laboratory assessment of serum zinc level, dietary assessment of food frequency and usual zinc intake. We considered subjects with serum zinc concentration of /-7.7 to 12.3 umol/l mild to moderately zinc deficient. The prevalence of zinc deficiency among the studied sample was 2.7%. We found mild to moderate zinc deficiency among 55.7% of the study sample. Dietary zinc intake assessment showed that 74.8% of the studied sample consumed less than the recommended intake, and in 62.3%, the intakes were deficient and grossly deficient. Mean daily zinc ranged from 5.2 mg in children to 8.5 mg in adults. We observed a high prevalence of mild to moderate zinc deficiency, with inadequate dietary zinc intake among a considerable proportion of the studied sample. Zinc supplementation may be an effective public health intervention means to improve the zinc status of the population. (author)

Zinc release contributes to hypoglycemia-induced neuronal death.

Science.gov (United States)

Suh, Sang Won; Garnier, Philippe; Aoyama, Koji; Chen, Yongmei; Swanson, Raymond A

2004-08-01

Neurons exposed to zinc exhibit activation of poly(ADP-ribose) polymerase-1 (PARP-1), an enzyme that normally participates in DNA repair but promotes cell death when extensively activated. Endogenous, vesicular zinc in brain is released to the extracellular space under conditions causing neuronal depolarization. Here, we used a rat model of insulin-induced hypoglycemia to assess the role of zinc release in PARP-1 activation and neuronal death after severe hypoglycemia. Zinc staining with N-(6-methoxy-8-quinolyl)-para-toluenesulfonamide (TSQ) showed depletion of presynaptic vesicular zinc from hippocampal mossy fiber terminals and accumulation of weakly bound zinc in hippocampal CA1 cell bodies after severe hypoglycemia. Intracerebroventricular injection of the zinc chelator calcium ethylene-diamine tetraacetic acid (CaEDTA) blocked the zinc accumulation and significantly reduced hypoglycemia-induced neuronal death. CaEDTA also attenuated the accumulation of poly(ADP-ribose), the enzymatic product of PARP-1, in hippocampal neurons. These results suggest that zinc translocation is an intermediary step linking hypoglycemia to PARP-1 activation and neuronal death.

LiZIP3 is a cellular zinc transporter that mediates the tightly regulated import of zinc in Leishmania infantum parasites

Science.gov (United States)

Carvalho, Sandra; da Silva, Rosa Barreira; Shawki, Ali; Castro, Helena; Lamy, Márcia; Eide, David; Costa, Vítor; Mackenzie, Bryan; Tomás, Ana M.

2016-01-01

Summary Cellular zinc homeostasis ensures that the intracellular concentration of this element is kept within limits that enable its participation in critical physiological processes without exerting toxic effects. We report here the identification and characterization of the first mediator of zinc homeostasis in Leishmania infantum, LiZIP3, a member of the ZIP family of divalent metal-ion transporters. The zinc transporter activity of LiZIP3 was first disclosed by its capacity to rescue the growth of Saccharomyces cerevisiae strains deficient in zinc acquisition. Subsequent expression of LiZIP3 in Xenopus laevis oocytes was shown to stimulate the uptake of a broad range of metal ions, among which Zn2+ was the preferred LiZIP3 substrate (K0.5 ≈ 0.1 μM). Evidence that LiZIP3 functions as a zinc importer in L. infantum came from the observations that the protein locates to the cell membrane and that its overexpression leads to augmented zinc internalization. Importantly, expression and cell-surface location of LiZIP3 are lost when parasites face high zinc bioavailability. LiZIP3 decline in response to zinc is regulated at the mRNA level in a process involving (a) short-lived protein(s). Collectively, our data reveal that LiZIP3 enables L. infantum to acquire zinc in a highly regulated manner, hence contributing to zinc homeostasis. PMID:25644708

Equilibrios químicos en bioadsorción

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Romera, E.

2007-02-01

Full Text Available An experimental study of biosorption was carried out using six different kinds of algae and five different heavy metals (cadmium, copper, nickel, lead and zinc. Experimental data fitted very well to Langmuir’s model and this allowed to predict the behaviour of the biomass under specific working conditions. Using the equations of the model under different initial assumptions, a series of mathematical calculations were done for monometallic, bimetallic and trimetallic systems. The most complicated calculation is that in which, knowing the initial metal concentration (C₀, it is necessary to calculate the conditions reached at the equilibrium, this is, q_e and C_e. This assumption is of great interest from the point of view of the actual applicability of the process. However, in this case, it is necessary to solve very complex mathematical equations which, for multimetallic systems, are of degree n+1, where n is the number of ions present in solution.The excellent correlation between experimental and theoretical data demonstrates that the  biosorption process can be modelling.

Se ha realizado un estudio experimental de bioadsorción utilizando seis tipos diferentes de algas y cinco metales pesados (cadmio, cobre, níquel, plomo y zinc. El buen ajuste de los datos experimentales al modelo de Langmuir ha permitido poder predecir el comportamiento de la biomasa en unas condiciones determinadas de trabajo. Todo ello, en base a una serie de cálculos matemáticos, utilizando las propias ecuaciones del modelo y bajo distintos supuestos iniciales de cálculo, tanto en sistemas monometálicos como en sistemas bimetálicos y trimetálicos. El supuesto de cálculo más complicado es el que, conociendo la concentración metálica inicial (C₀ se deseen calcular las condiciones que se alcanzarían en el equilibrio, es decir, q_e y C_e. Este, sería un supuesto de máximo interés de cara a

A novel thiolated human-like collage zinc complex as a promising zinc supplement: physicochemical characteristics and biocompatibility.

Science.gov (United States)

Zhu, Chenhui; Ma, Xiaoxuan; Wang, Yonghui; Mi, Yu; Fan, Daidi; Deng, Jianjun; Xue, Wenjiao

2014-11-01

To improve zinc binding ability to human-like collagen (HLC) and stability of metal complex, HLC was thiolated by mercaptosuccinylation reaction with S-acetylmercaptosuccinic anhydride (S-AMSA) at pH8.0. One mole of thiolated HLC-Zn (SHLC-Zn) complex possessed 24.3mol zinc ions when pH was 8.0 and zinc concentration was 15 mM. The physicochemical properties and biocompatibility of thiolated HLC-Zn (SHLC-Zn) complex were investigated by UV-vis, CD, electrophoresis analysis, differential scanning calorimetry (DSC) and cell viability assay, respectively. The results showed that SHLC-Zn complex(1) exhibited higher zinc ions than that of native HLC and still maintained the secondary structure of HLC though interaction occurred between SHLC and zinc ions, (2) increased the apparent molecular weight when compared with native HLC, (3) exhibited greater thermal stability than native HLC, and (4) presented toxicity free for BHK cells. This study suggests that the SHLC-Zn complex is a potential nutrition as well as zinc supplement in the medical application. Copyright © 2014 Elsevier B.V. All rights reserved.

Arsenite binding-induced zinc loss from PARP-1 is equivalent to zinc deficiency in reducing PARP-1 activity, leading to inhibition of DNA repair

Energy Technology Data Exchange (ETDEWEB)

Sun, Xi; Zhou, Xixi [Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Du, Libo [Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Liu, Wenlan [Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Liu, Yang [Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Hudson, Laurie G. [Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Liu, Ke Jian, E-mail: kliu@salud.unm.edu [Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States)

2014-01-15

Inhibition of DNA repair is a recognized mechanism for arsenic enhancement of ultraviolet radiation-induced DNA damage and carcinogenesis. Poly(ADP-ribose) polymerase-1 (PARP-1), a zinc finger DNA repair protein, has been identified as a sensitive molecular target for arsenic. The zinc finger domains of PARP-1 protein function as a critical structure in DNA recognition and binding. Since cellular poly(ADP-ribosyl)ation capacity has been positively correlated with zinc status in cells, we hypothesize that arsenite binding-induced zinc loss from PARP-1 is equivalent to zinc deficiency in reducing PARP-1 activity, leading to inhibition of DNA repair. To test this hypothesis, we compared the effects of arsenite exposure with zinc deficiency, created by using the membrane-permeable zinc chelator TPEN, on 8-OHdG formation, PARP-1 activity and zinc binding to PARP-1 in HaCat cells. Our results show that arsenite exposure and zinc deficiency had similar effects on PARP-1 protein, whereas supplemental zinc reversed these effects. To investigate the molecular mechanism of zinc loss induced by arsenite, ICP-AES, near UV spectroscopy, fluorescence, and circular dichroism spectroscopy were utilized to examine arsenite binding and occupation of a peptide representing the first zinc finger of PARP-1. We found that arsenite binding as well as zinc loss altered the conformation of zinc finger structure which functionally leads to PARP-1 inhibition. These findings suggest that arsenite binding to PARP-1 protein created similar adverse biological effects as zinc deficiency, which establishes the molecular mechanism for zinc supplementation as a potentially effective treatment to reverse the detrimental outcomes of arsenic exposure. - Highlights: • Arsenite binding is equivalent to zinc deficiency in reducing PARP-1 function. • Zinc reverses arsenic inhibition of PARP-1 activity and enhancement of DNA damage. • Arsenite binding and zinc loss alter the conformation of zinc finger

Arsenite binding-induced zinc loss from PARP-1 is equivalent to zinc deficiency in reducing PARP-1 activity, leading to inhibition of DNA repair

International Nuclear Information System (INIS)

Sun, Xi; Zhou, Xixi; Du, Libo; Liu, Wenlan; Liu, Yang; Hudson, Laurie G.; Liu, Ke Jian

2014-01-01

Inhibition of DNA repair is a recognized mechanism for arsenic enhancement of ultraviolet radiation-induced DNA damage and carcinogenesis. Poly(ADP-ribose) polymerase-1 (PARP-1), a zinc finger DNA repair protein, has been identified as a sensitive molecular target for arsenic. The zinc finger domains of PARP-1 protein function as a critical structure in DNA recognition and binding. Since cellular poly(ADP-ribosyl)ation capacity has been positively correlated with zinc status in cells, we hypothesize that arsenite binding-induced zinc loss from PARP-1 is equivalent to zinc deficiency in reducing PARP-1 activity, leading to inhibition of DNA repair. To test this hypothesis, we compared the effects of arsenite exposure with zinc deficiency, created by using the membrane-permeable zinc chelator TPEN, on 8-OHdG formation, PARP-1 activity and zinc binding to PARP-1 in HaCat cells. Our results show that arsenite exposure and zinc deficiency had similar effects on PARP-1 protein, whereas supplemental zinc reversed these effects. To investigate the molecular mechanism of zinc loss induced by arsenite, ICP-AES, near UV spectroscopy, fluorescence, and circular dichroism spectroscopy were utilized to examine arsenite binding and occupation of a peptide representing the first zinc finger of PARP-1. We found that arsenite binding as well as zinc loss altered the conformation of zinc finger structure which functionally leads to PARP-1 inhibition. These findings suggest that arsenite binding to PARP-1 protein created similar adverse biological effects as zinc deficiency, which establishes the molecular mechanism for zinc supplementation as a potentially effective treatment to reverse the detrimental outcomes of arsenic exposure. - Highlights: • Arsenite binding is equivalent to zinc deficiency in reducing PARP-1 function. • Zinc reverses arsenic inhibition of PARP-1 activity and enhancement of DNA damage. • Arsenite binding and zinc loss alter the conformation of zinc finger

Decrease of non-point zinc runoff using porous concrete.

Science.gov (United States)

Harada, Shigeki; Komuro, Yoshinori

2010-01-01

The use of porous concrete columns to decrease the amount of zinc in stormwater runoff is examined. The concentration of zinc in a simulated stormwater fluid (zinc acetate solution), fed through concrete columns (slashed circle10x10cm) decreased by 50-81%, suggesting physical adsorption of zinc by the porous concrete. We propose the use of porous concrete columns (slashed circle50x10cm) as the base of sewage traps. Longer-term, high-zinc concentration monitoring revealed that porous concrete blocks adsorb 38.6mgcm(-3) of zinc. A period of no significant zinc runoff (with an acceptable concentration of zinc in runoff of 0.03mgL(-1), a zinc concentration equal to the Japanese Environmental Standard) is estimated for 41years using a 1-ha catchment area with 20 porous concrete sewage traps. Scanning electron microscopy of the porous concrete used in this study indicates that the needle-like particles formed by hydration action significantly increase zinc adsorption. Evidence suggests that the hydrant is ettringite and has an important role in zinc adsorption, the resulting immobilization of zinc and the subsequent effects on groundwater quality. Copyright 2009 Elsevier Ltd. All rights reserved.

Zinc injection method and device in nuclear power plant

International Nuclear Information System (INIS)

Maehara, Kazumi; Negishi, Itaru; Deguchi, Tatsuya; Ino, Takao; Sasaki, Noriyuki; Yotsuyanagi, Tadashi; Tobara, Hirotaka.

1996-01-01

The present invention concerns a method of injecting zinc into reactor water, and it can supply a solution of zinc at a high concentration by improving the solubility of zinc. Namely, zinc is used as a solute and is dissolved in an aqueous solution containing an electrolyte such as carbonic acid. The resultant zinc solution at a high concentration is injected to reactor water. In the device of the present invention, (1) a dissolution vessel for dissolving zinc comprises a zinc supply means at an upper portion thereof and a carbonic acid gas supply means at a lower portion, (2) an injection means supplies the solution in which zinc is dissolved at a high concentration to reactor water. An aqueous solution saturated with a carbonic acid gas is used as a solvent for dissolving zinc into reactor water at a high concentration. The dissolution vessel has a gas diffusion pipe at the bottom for introducing the carbonic acid gas and has a stirrer in the inside. Zinc is supplied continuously or discontinuously. Raw material zinc may be in the form of a plate, rod, granule, or powder, however, powdery zinc is preferably used. (I.S.)

Modulation of extrasynaptic NMDA receptors by synaptic and tonic zinc.

Science.gov (United States)

Anderson, Charles T; Radford, Robert J; Zastrow, Melissa L; Zhang, Daniel Y; Apfel, Ulf-Peter; Lippard, Stephen J; Tzounopoulos, Thanos

2015-05-19

Many excitatory synapses contain high levels of mobile zinc within glutamatergic vesicles. Although synaptic zinc and glutamate are coreleased, it is controversial whether zinc diffuses away from the release site or whether it remains bound to presynaptic membranes or proteins after its release. To study zinc transmission and quantify zinc levels, we required a high-affinity rapid zinc chelator as well as an extracellular ratiometric fluorescent zinc sensor. We demonstrate that tricine, considered a preferred chelator for studying the role of synaptic zinc, is unable to efficiently prevent zinc from binding low-nanomolar zinc-binding sites, such as the high-affinity zinc-binding site found in NMDA receptors (NMDARs). Here, we used ZX1, which has a 1 nM zinc dissociation constant and second-order rate constant for binding zinc that is 200-fold higher than those for tricine and CaEDTA. We find that synaptic zinc is phasically released during action potentials. In response to short trains of presynaptic stimulation, synaptic zinc diffuses beyond the synaptic cleft where it inhibits extrasynaptic NMDARs. During higher rates of presynaptic stimulation, released glutamate activates additional extrasynaptic NMDARs that are not reached by synaptically released zinc, but which are inhibited by ambient, tonic levels of nonsynaptic zinc. By performing a ratiometric evaluation of extracellular zinc levels in the dorsal cochlear nucleus, we determined the tonic zinc levels to be low nanomolar. These results demonstrate a physiological role for endogenous synaptic as well as tonic zinc in inhibiting extrasynaptic NMDARs and thereby fine tuning neuronal excitability and signaling.

Modulation of extrasynaptic NMDA receptors by synaptic and tonic zinc

Science.gov (United States)

Anderson, Charles T.; Radford, Robert J.; Zastrow, Melissa L.; Zhang, Daniel Y.; Apfel, Ulf-Peter; Lippard, Stephen J.; Tzounopoulos, Thanos

2015-01-01

Many excitatory synapses contain high levels of mobile zinc within glutamatergic vesicles. Although synaptic zinc and glutamate are coreleased, it is controversial whether zinc diffuses away from the release site or whether it remains bound to presynaptic membranes or proteins after its release. To study zinc transmission and quantify zinc levels, we required a high-affinity rapid zinc chelator as well as an extracellular ratiometric fluorescent zinc sensor. We demonstrate that tricine, considered a preferred chelator for studying the role of synaptic zinc, is unable to efficiently prevent zinc from binding low-nanomolar zinc-binding sites, such as the high-affinity zinc-binding site found in NMDA receptors (NMDARs). Here, we used ZX1, which has a 1 nM zinc dissociation constant and second-order rate constant for binding zinc that is 200-fold higher than those for tricine and CaEDTA. We find that synaptic zinc is phasically released during action potentials. In response to short trains of presynaptic stimulation, synaptic zinc diffuses beyond the synaptic cleft where it inhibits extrasynaptic NMDARs. During higher rates of presynaptic stimulation, released glutamate activates additional extrasynaptic NMDARs that are not reached by synaptically released zinc, but which are inhibited by ambient, tonic levels of nonsynaptic zinc. By performing a ratiometric evaluation of extracellular zinc levels in the dorsal cochlear nucleus, we determined the tonic zinc levels to be low nanomolar. These results demonstrate a physiological role for endogenous synaptic as well as tonic zinc in inhibiting extrasynaptic NMDARs and thereby fine tuning neuronal excitability and signaling. PMID:25947151

Zinc electrode shape change II. Process and mechanism

NARCIS (Netherlands)

Einerhand, R.E.F.; Visscher, W.; de Goeij, J.J.M.; Barendrecht, E.

1991-01-01

The process and mechanism of zinc electrode shape change is investigated with the radiotracer technique. It is shownthat during repeated cycling of the nickel oxide/zinc battery zinc material is transported over the zinc electrode via the battery electrolyte. During charge as well as during

Zinc dosing and glucose tolerance in humans

International Nuclear Information System (INIS)

Greenley, S.; Taylor, M.

1986-01-01

Animal data suggest the existence of a physiologic relationship between glucoregulatory hormones and zinc metabolism. In order to investigate this proposed relationship in humans, they examined the effect of moderately elevated plasma zinc levels on blood glucose clearance. Eight women (24-37 yrs) served as subjects for the study. Fasted volunteers were tested under two experimental conditions (a) ingestion of 50 g D-glucose (b) ingestion of 25 mg zinc followed 60 min later by ingestion of 50 g D-glucose. Five ml venous blood was drawn into trace-metal-free, fluoride-containing vacutainer tubes prior to and 15, 30, 45, 60, 90, and 120 min after glucose ingestion. Plasma was analyzed for glucose and zinc; glycemic responses were quantified by computing areas under the curves and times to peak concentration. Their human data indicate varied glycemic responses to the acute elevation of plasma zinc: 4 subjects showed little apparent effect; 3 subjects marginally increased either the area under the curve or time to peak and 1 subject (classified as suspect diabetic in the non-zinc condition) showed marked improvement in glycemic response following zinc ingestion. Their preliminary results suggest that blood glucose clearance may be affected in some individuals by the acute elevation of plasma zinc

Determinación de la adsorción de cadmio mediante isotermas de adsorción en suelos agrícolas venezolanos Determination of the adsorption of cadmium by adsorption isotherms in agricultural soils venezuelans

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Nereida Sánchez

2011-04-01

Full Text Available El cadmio es un metal pesado que tiende a acumularse en la superficie del suelo. En los últimos años, las actividades antropogénicas han ocasionado un incremento en los niveles de este metal en suelos agrícolas generando gran preocupación ambiental debido a su movilidad y lixiviación en el perfil del suelo y a la facilidad con que es absorbido por las plantas. El objetivo de este trabajo fue determinar la capacidad de adsorción de cadmio, de cuatro suelos venezolanos de uso agrícola con diferencias texturales. Para determinar la capacidad de adsorción del metal en cada suelo, inicialmente se determinó el tiempo óptimo de agitación; el cual fue de 2 horas y la relación suelo-solución enriquecedora de Cd; la cual fue de 1:50. Con estos parámetros se elaboraron las isotermas de adsorción para los suelos y se compararon los modelos de Freundlich y Langmuir. Los resultados mostraron que el modelo matemático de Freundlich es el que mejor describe la cinética de la reacción y la capacidad de adsorción de Cd por los suelos, siendo los que poseen mayores contenidos de arcilla, MO y pH ácidos los de mayor capacidad de adsorción.Cadmium is a heavy metal which tends to accumulate in the soil surface. In recent years, anthropogenic activities have caused an increase of the levels of this metal in agricultural soils causing great environmental concern due to their mobility and leaching in the soil profile and the ease way to be absorbed by plants. The purpose of this study was to determine the adsorption capacity of cadmium in four Venezuelan agricultural soils with different texture. To determine the adsorption capacity of Cd in each soil, first of all the optimal time of stirring was determined, which was two hours and the soilenriching solution of Cd, which was (1/50. With these parameters, cadmium adsorption isotherms for all soils were developed and compared with Freundlich and Langmuir models. The data showed that the Freundlich

Organically pillared layered zinc hydroxides

International Nuclear Information System (INIS)

Kongshaug, K.O.; Fjellvaag, Helmer

2004-01-01

The two organically pillared layered zinc hydroxides [Zn 2 (OH) 2 (ndc)], CPO-6, and [Zn 3 (OH) 4 (bpdc)], CPO-7, were obtained in hydrothermal reactions between 2,6-naphthalenedicarboxylic acid (ndc) and zinc nitrate (CPO-6) and 4,4'biphenyldicarboxylate (bpdc) and zinc nitrate (CPO-7), respectively. In CPO-6, the tetrahedral zinc atoms are connected by two μ 2 -OH groups and two carboxylate oxygen atoms, forming infinite layers extending parallel to the bc-plane. These layers are pillared by ndc to form a three-dimensional structure. In CPO-7, the zinc hydroxide layers are containing four-, five- and six coordinated zinc atoms, and the layers are built like stairways running along the [001] direction. Each step is composed of three infinite chains running in the [010] direction. Both crystal structures were solved from conventional single crystal data. Crystal data for CPO-6: Monoclinic space group P2 1 /c (No. 14), a=11.9703(7), b=7.8154(5), c=6.2428(4) A, β=90.816(2) deg., V=583.97(6) A 3 and Z=4. Crystal data for CPO-7: Monoclinic space group C2/c (No. 15), a=35.220(4), b=6.2658(8), c=14.8888(17) A, β=112.580(4) deg., V=3033.8(6) A 3 and Z=8. The compounds were further characterized by thermogravimetric- and chemical analysis

Horse Liver Alcohol Dehydrogenase: Zinc Coordination and Catalysis

Energy Technology Data Exchange (ETDEWEB)

Plapp, Bryce V.; Savarimuthu, Baskar Raj; Ferraro, Daniel J.; Rubach, Jon K.; Brown, Eric N.; Ramaswamy, S. (Iowa)

2017-07-07

During catalysis by liver alcohol dehydrogenase (ADH), a water bound to the catalytic zinc is replaced by the oxygen of the substrates. The mechanism might involve a pentacoordinated zinc or a double-displacement reaction with participation by a nearby glutamate residue, as suggested by studies of human ADH3, yeast ADH1, and some other tetrameric ADHs. Zinc coordination and participation of water in the enzyme mechanism were investigated by X-ray crystallography. The apoenzyme and its complex with adenosine 5'-diphosphoribose have an open protein conformation with the catalytic zinc in one position, tetracoordinated by Cys-46, His-67, Cys-174, and a water molecule. The bidentate chelators 2,2'-bipyridine and 1,10-phenanthroline displace the water and form a pentacoordinated zinc. The enzyme–NADH complex has a closed conformation similar to that of ternary complexes with coenzyme and substrate analogues; the coordination of the catalytic zinc is similar to that found in the apoenzyme, except that a minor, alternative position for the catalytic zinc is ~1.3 Å from the major position and closer to Glu-68, which could form the alternative coordination to the catalytic zinc. Complexes with NADH and N-1-methylhexylformamide or N-benzylformamide (or with NAD+ and fluoro alcohols) have the classical tetracoordinated zinc, and no water is bound to the zinc or the nicotinamide rings. The major forms of the enzyme in the mechanism have a tetracoordinated zinc, where the carboxylate group of Glu-68 could participate in the exchange of water and substrates on the zinc. Hydride transfer in the Michaelis complexes does not involve a nearby water.

HUBUNGAN ANTARA ZINC SERUM DENGAN STATUS GIZI LANSIA

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Fitrah Emawati

2012-11-01

Full Text Available RELATIONSHIP BETWEEN ZINC SERUM AND NUTRITIONAL STATUS OF ELDERLY PEOPLE.Background: The findings of study that 30% in Bogor and 27% in Jakarta of elderly people were undernourished. Malnutrition may occur due to infection and low food intake. Among elderly people, one of the factors that causes low food intake is affected by impairment of taste sensory and teeth function. The impairment of taste sensory is influenced by zinc status in the body.Objective: To collect food consumption pattem data of zinc rich foods, zinc concentration in serum and to analyze association of zinc concentration and nutritional status.Methods: Research design was cross sectional, and conducted in two sub districts in Bogor city. The respondents were women in 60-75 years of age, no suffering from illnesses and chronically disease. The total respondent was 90 people, and divided into three groups of 30 peoples. Data gathered included respondent identity, physical examination, anthropometry, blood biochemical and zinc dietary consumption.Results: Zinc dietary consumption adequacy of underweight group was only 30% of recommended dietary allowance, while for normal and overweight groups were 40% of dietary allowance. Zinc serum concentration of underweight group (82 ug/dl was not significantly different with normal group (85 ug/dl, however differed significantly (p<0.05 with overweight group (95 ug/dl. Underweight group suffered 40% zinc deficiency, 27% for normal and only 7% for overweight group.Conclusions: Zinc deficiency was more prevalent in underweight group than that of normal and overweight group. [Panel Gizi Makan 2002,25: 26-33.Keywords: zinc serum concentration, zinc dietary consumption, underweight

Behavioral impairments in animal models for zinc deficiency

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Simone eHagmeyer

2015-01-01

Full Text Available Apart from teratogenic and pathological effects of zinc deficiency such as the occurrence of skin lesions, anorexia, growth retardation, depressed wound healing, altered immune function, impaired night vision, and alterations in taste and smell acuity, characteristic behavioral changes in animal models and human patients suffering from zinc deficiency have been observed. Given that it is estimated that about 17% of the worldwide population are at risk for zinc deficiency and that zinc deficiency is associated with a variety of brain disorders and disease states in humans, it is of major interest to investigate, how these behavioral changes will affect the individual and a putative course of a disease. Thus, here, we provide a state of the art overview about the behavioral phenotypes observed in various models of zinc deficiency, among them environmentally produced zinc deficient animals as well as animal models based on a genetic alteration of a particular zinc homeostasis gene. Finally, we compare the behavioral phenotypes to the human condition of mild to severe zinc deficiency and provide a model, how zinc deficiency that is associated with many neurodegenerative and neuropsychological disorders might modify the disease pathologies.

Nutrição do feijoeiro e intensidade da antracnose em função da aplicação de silício e cobre = Nutrition in bean plants and anthracnose intensity in function of silicon and copper application

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Sylvia Raquel Gomes Moraes

2009-04-01

Full Text Available O objetivo deste trabalho foi avaliar o efeito do silicato de cálcio e do sulfato de cobre na intensidade da antracnose e no teor nutricional do feijoeiro. O experimento foi conduzido em blocos casualizados em arranjo fatorial 4 x 4 (quatro doses de silicato decálcio, com quatro doses de sulfato de cobre e dois tratamentos adicionais (plantas nãoinoculadas e plantas pulverizadas com Benomyl. Foram feitas quatro avaliações da incidência e da severidade da doença, além de se mensurar a área foliar total. Ao término das avaliações, os dados de incidência e de severidade foram integrados ao longo do tempo, obtendo-se a área abaixo da curva de progresso da incidência (AACPI e da severidade (AACPS. Os teores de N, P, K, Ca, Mg, B, Cu, Fe, Mn, Zn, Si e lignina foram avaliados naparte aérea. Observou-se decréscimo linear da AACPI com o aumento das doses de silicato de cálcio. Com o aumento das doses de cobre, houve redução de 35% na AACPS. O suprimento de silicato e de cobre alterou o teor de K, Mg, S, Zn, Ca e Si da parte aérea do feijoeiro.The objective of this work was to evaluate the effect of calcium silicate and copper sulfate on anthracnose intensity and nutrition of bean plants. The experiment was conducted using an experimental design in randomized blocks following a 4 x 4 factorial arrangement, (four levels of calcium silicate and four levels of copper sulfate and two additional treatments (plants without inoculation and plantssprinkled with Benomyl. Four evaluations of the incidence and severity of anthracnose were done, in addition to measuring total leaf area. At the end of the evaluations, incidence and severity data were integrated over time, obtaining the area under disease progress curve (AUDPC. Contents of N, P, K, Ca, Mg, B, Cu, Fe, Mn, Zn, Si and lignin were determined in the aerial part. A linear decrease of the intensity AUDPC was observed with the increase of the doses of calcium silicate. The severity AUDPC

Zinc-Catalyzed Synthesis of Conjugated Dienoates through Unusual Cross-Couplings of Zinc Carbenes with Diazo Compounds.

Science.gov (United States)

Mata, Sergio; González, María J; González, Jesús; López, Luis A; Vicente, Rubén

2017-01-23

Zinc-catalyzed selective cross-coupling of two carbene sources, such as vinyl diazo compounds and enynones, enabled the synthesis of conjugated dienoate derivatives. This reaction involved the unprecedented coupling of a zinc furyl carbene with vinyl diazo compounds through the γ-carbon. Alternatively, dienoates were also prepared by a commutative cross-coupling of zinc vinyl carbenes generated from cyclopropenes and simple diazo compounds. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

[In Process Citation].

Science.gov (United States)

Wang, Bingsong; Li, Yijun; Wu, Xiaolu; Liu, Qingqing; Tang, Xue; Wang, Zuo

2016-03-25

Objetivos: oligoelementos como zinc (Zn), hierro (Fe) y cobre (Cu) tienen una influencia significativa en el mantenimiento de la función inmune y del metabolismo normales; modulan la función immune e influyen en la susceptibilidad del organismo ante infecciones. Pero la relación entre trazas de estos elementos y la bronconeumonía resultó incierta. Métodos: en este estudio fueron incluidos 28 niños con bronconeumonía y 46 niños sanos agrupados por edad. Se determinaron los niveles de Zn, Cu, Fe, calcio (Ca) y/o magnesio (Mg) en el suero de los niños con bronconeumonía y sin ella mediante espectrofotometría de absorción atómica. Resultados: los resultados muestran que varios niveles de microelementos como Zn, Ca, Mg y Fe en el grupo con bronconeumonía son menores que en el grupo control. En el grupo de niños con bronconeumonía el nivel de Ca en el suero está asociado positivamente con el zinc (Zn) (p < 0,05) y el hierro (Fe) (p < 0,05), mientras que hay una correlación positiva entre el cobre (Cu) y el calcio (Ca) (p < 0,05), magnesio (mg) (p < 0,05). Conclusión: el nivel de oligoelemento en el suero puede estar asociado con el riesgo de bronconeumonía entre los niños.

Fluorescent zinc sensor with minimized proton-induced interferences: photophysical mechanism for fluorescence turn-on response and detection of endogenous free zinc ions.

Science.gov (United States)

Kwon, Ji Eon; Lee, Sumin; You, Youngmin; Baek, Kyung-Hwa; Ohkubo, Kei; Cho, Jaeheung; Fukuzumi, Shunichi; Shin, Injae; Park, Soo Young; Nam, Wonwoo

2012-08-20

A new fluorescent zinc sensor (HNBO-DPA) consisting of 2-(2'-hydroxy-3'-naphthyl)benzoxazole (HNBO) chromophore and a di(2-picolyl)amine (DPA) metal chelator has been prepared and examined for zinc bioimaging. The probe exhibits zinc-induced fluorescence turn-on without any spectral shifts. Its crystal structure reveals that HNBO-DPA binds a zinc ion in a pentacoordinative fashion through the DPA and HNBO moieties. Steady-state photophysical studies establish zinc-induced deprotonation of the HNBO group. Nanosecond and femtosecond laser flash photolysis and electrochemical measurements provide evidence for zinc-induced modulation of photoinduced electron transfer (PeT) from DPA to HNBO. Thus, the zinc-responsive fluorescence turn-on is attributed to suppression of PeT exerted by deprotonation of HNBO and occupation of the electron pair of DPA, a conclusion that is further supported by density functional theory and time-dependent density functional theory (DFT/TD-DFT) calculations. Under physiological conditions (pH 7.0), the probe displays a 44-fold fluorescence turn-on in response to zinc ions with a K(d) value of 12 pM. The fluorescent response of the probe to zinc ions is conserved over a broad pH range with its excellent selectivity for zinc ions among biologically relevant metal ions. In particular, its sensing ability is not altered by divalent transition metal ions such as Fe(II), Cu(II), Cd(II), and Hg(II). Cell experiments using HNBO-DPA show its suitability for monitoring intracellular zinc ions. We have also demonstrated applicability of the probe to visualize intact zinc ions released from cells that undergo apoptosis. More interestingly, zinc-rich pools in zebrafish embryos are traced with HNBO-DPA during early developmental stages. The results obtained from the in vitro and in vivo imaging studies demonstrate the practical usefulness of the probe to detect zinc ions.

Research and application of zinc injection in PWRs

International Nuclear Information System (INIS)

Jiang Lei

2012-01-01

In the middle 1990s, some PWRs in USA and Germany started to inject Zinc into the reactor coolant system for reducing both radiation fields and primary water stress corrosion cracking (PWSCC). Based on data from the labs and experience in the demonstration pants, Zinc injection obviously reduced radiation fields, and effectively mitigated PWSCC. Plants in USA injected high concentration zinc that is 15 ppb to 40 ppb to restrained PWSCC. Whereas, plants in Germany injected low concentration zinc that is 5 ppb to 10 ppb to reduce radiation fields. There are more than ten years at aspect of zinc rejection in overseas PWR, but domestic plants don't add zinc. The building PWR in Zhejiang Sanmen is the first AP1000 unit in the world, according to requirement of designers, it will start to inject zinc in the initial fuel cycle. (author)

ZINC MITIGATION INTERIM REPORT - THERMODYNAMIC STUDY

Energy Technology Data Exchange (ETDEWEB)

Korinko, P.

2010-12-17

An experimental program was initiated in order to develop and validate conditions that will effectively trap Zn vapors that are released during extraction. The proposed work is broken down into three tasks. The first task is to determine the effectiveness of various pore sizes of filter elements. The second task is to determine the effect of filter temperature on zinc vapor deposition. The final task is to determine whether the zinc vapors can be chemically bound. The approach for chemically binding the zinc vapors has two subtasks, the first is a review of literature and thermodynamic calculations and the second is an experimental approach using the best candidates. This report details the results of the thermodynamic calculations to determine feasibility of chemically binding the zinc vapors within the furnace module, specifically the lithium trap (1). A review of phase diagrams, literature, and thermodynamic calculations was conducted to determine if there are suitable materials to capture zinc vapor within the lithium trap of the extraction basket. While numerous elements exist that form compounds with zinc, many of these also form compounds with hydrogen or the water that is present in the TPBARs. This relatively comprehensive review of available data indicates that elemental cobalt and copper and molybdenum trioxide (MoO3) may have the requisite properties to capture zinc and yet not be adversely affected by the extraction gases and should be considered for testing.

Zinc biofortification of cereals

DEFF Research Database (Denmark)

Palmgren, Michael; Clemens, Stephan; Williams, Lorraine E.

2008-01-01

The goal of biofortification is to develop plants that have an increased content of bioavailable nutrients in their edible parts. Cereals serve as the main staple food for a large proportion of the world population but have the shortcoming, from a nutrition perspective, of being low in zinc...... and other essential nutrients. Major bottlenecks in plant biofortification appear to be the root-shoot barrier and - in cereals - the process of grain filling. New findings demonstrate that the root-shoot distribution of zinc is controlled mainly by heavy metal transporting P1B-ATPases and the metal...... tolerance protein (MTP) family. A greater understanding of zinc transport is important to improve crop quality and also to help alleviate accumulation of any toxic metals....

Oral zinc for treating diarrhoea in children

Science.gov (United States)

Lazzerini, Marzia; Wanzira, Humphrey

2016-01-01

Background In developing countries, diarrhoea causes around 500,000 child deaths annually. Zinc supplementation during acute diarrhoea is currently recommended by the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF). Objectives To evaluate oral zinc supplementation for treating children with acute or persistent diarrhoea. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (the Cochrane Library 2016, Issue 5), MEDLINE, Embase, LILACS, CINAHL, mRCT, and reference lists up to 30 September 2016. We also contacted researchers. Selection criteria Randomized controlled trials (RCTs) that compared oral zinc supplementation with placebo in children aged one month to five years with acute or persistent diarrhoea, including dysentery. Data collection and analysis Both review authors assessed trial eligibility and risk of bias, extracted and analysed data, and drafted the review. The primary outcomes were diarrhoea duration and severity. We summarized dichotomous outcomes using risk ratios (RR) and continuous outcomes using mean differences (MD) with 95% confidence intervals (CI). Where appropriate, we combined data in meta-analyses (using either a fixed-effect or random-effects model) and assessed heterogeneity. We assessed the certainty of the evidence using the GRADE approach. Main results Thirty-three trials that included 10,841 children met our inclusion criteria. Most included trials were conducted in Asian countries that were at high risk of zinc deficiency. Acute diarrhoea There is currently not enough evidence from well-conducted RCTs to be able to say whether zinc supplementation during acute diarrhoea reduces death or number of children hospitalized (very low certainty evidence). In children older than six months of age, zinc supplementation may shorten the average duration of diarrhoea by around half a day (MD −11.46 hours, 95% CI −19.72 to −3.19; 2581 children, 9 trials, low

The Relevance of the Colon to Zinc Nutrition

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Geetha Lavaniya Gopalsamy

2015-01-01

Full Text Available Globally, zinc deficiency is widespread, despite decades of research highlighting its negative effects on health, and in particular upon child health in low-income countries. Apart from inadequate dietary intake of bioavailable zinc, other significant contributors to zinc deficiency include the excessive intestinal loss of endogenously secreted zinc and impairment in small intestinal absorptive function. Such changes are likely to occur in children suffering from environmental (or tropical enteropathy (EE—an almost universal condition among inhabitants of developing countries characterized by morphologic and functional changes in the small intestine. Changes to the proximal gut in environmental enteropathy will likely influence the nature and amount of zinc delivered into the large intestine. Consequently, we reviewed the current literature to determine if colonic absorption of endogenous or exogenous (dietary zinc could contribute to overall zinc nutriture. Whilst we found evidence that significant zinc absorption occurs in the rodent colon, and is favoured when microbially-fermentable carbohydrates (specifically resistant starch are consumed, it is unclear whether this process occur in humans and/or to what degree. Constraints in study design in the few available studies may well have masked a possible colonic contribution to zinc nutrition. Furthermore these few available human studies have failed to include the actual target population that would benefit, namely infants affected by EE where zinc delivery to the colon may be increased and who are also at risk of zinc deficiency. In conducting this review we have not been able to confirm a colonic contribution to zinc absorption in humans. However, given the observations in rodents and that feeding resistant starch to children is feasible, definitive studies utilising the dual stable isotope method in children with EE should be undertaken.

ECUACIÓN DE VELOCIDAD PARA LA ADSORCIÓN SOBRE UNA BENTONITA.

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David Rodríguez

2008-03-01

Full Text Available Se estudió la adsorción de dodecilbencenosulfonato de sodio, a 25 oC, sobre arcillas organofílicas obtenidas tratando una bentonita del Valle del Cauca con iones hexadeciltrimetil amonio y hexadecilbencildimetil amonio. El proceso de adsorción es relativamente rápido. Igualmente, se estudió la adsorción de cadmio, niquel y zinc sobre la bentonita en estado natural y se encontró que este proceso es muy rápido. En todos los casos estudiados se cumple la ley cinética correspondiente al proceso reversible y a la ecuación de velocidad que incluye la superficie de adsorbente disponible para la adsorción y en la que todos los órdenes parciales son iguales a uno.

CONCENTRAÇÕES RESIDUAIS DE COBRE, FERRO, MANGANÊS E ZINCO EM LATOSSOLO ROXO EUTRÓFICO SOB DIFERENTES TIPOS DE MANEJO RESIDUAL CONCENTRATION OF COPPER, IRON, MANGANESE AND ZINC IN EUTROPHIC 'LATOSSOLO ROXO’ UNDER DIFFERENT SOIL MANAGEMENTS

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Itamar Pereira de Oliveira

2007-09-01

Full Text Available

A exportação dos micronutrientes do solo pelos grãos e a queima dos restos culturais constituem os principais meios de esgotamento do solo. A correção da fertilidade e o manejo adequado do solo têm sido os meios usados para manter a produção de grãos. Desenvolveram-se culturas de soja, milho, arroz e feijão em um latossolo roxo eutrófico, submetidas a quatro sistemas de manejo: 1 plantio direto; 2 escarificação profunda; 3 grade aradora; e 4 aração profunda, e a três níveis de adubação: 1 fertilidade natural; 2 recomendação oficial para o Estado de Goiás; e 3 quantidade para cobrir a exportação de nutrientes pelos grãos. Os maiores valores do pH observados na camada superficial das áreas submetidas a aração profunda foram atribuídos à distribuição de bases, devido ao revolvimento do solo pelo arado de aiveca. Concentrações mais uniformes de manganês, ferro e zinco foram observadas onde se realizou a aração profunda. A camada entre 40-60 cm apresentou concentrações semelhantes em todos os tipos de manejo. As maiores concentrações de cobre na camada superficial e na camada mais profunda podem ser atribuídas à maior concentração de matéria orgânica e à origem do solo. Nenhuma diferença foi observada em relação à aplicação de fertilizantes.

PALAVRAS-CHAVE: Micronutrientes; plantio direto; solo de cerrado.

The removal of micronutrients from soil by grains and burning of cultural remains constitute the main means of soilexhaustion. The correction of soil fertility and the adapted soilmanagement have been the means used to maintain the grainproduction. The soybean, corn, rice and common bean crops were developed in an eutrophic ‘latossolo roxo’, submitted to fourmanagement systems: 1 no-till, 2 deep moldboard plowing, 3

A biokinetic model for zinc for use in radiation protection

International Nuclear Information System (INIS)

Leggett, R.W.

2012-01-01

The physiology of the essential trace element zinc has been studied extensively in human subjects using kinetic analysis of time-dependent measurements of administered zinc tracers. A number of biokinetic models describing zinc exchange between plasma and tissues and endogenous excretion of zinc have been derived as fits to data for specific study groups. More rudimentary biokinetic models for zinc have been developed to estimate radiation doses from internally deposited radioisotopes of zinc. The latter models are designed to provide broadly accurate estimates of cumulative decays of zinc radioisotopes in tissues and are not intended as realistic descriptions of the directions of movement of zinc in the body. This paper reviews biokinetic data for zinc and proposes a physiologically meaningful biokinetic model for systemic zinc for use in radiation protection. The proposed model bears some resemblance to zinc models developed in physiological studies but depicts a finer division of systemic zinc and is based on a broader spectrum of data than previous models. The proposed model and the model for zinc currently recommended by the International Commission on Radiological Protection yield reasonably similar estimates of total-body retention and effective dose for internally deposited radioisotopes of zinc but much different systemic distributions of activity and much different dose estimates for some individual tissues, particularly the liver. - Highlights: ► Zinc is an essential trace element with numerous functions in the human body. ► Several biokinetic models for zinc have been developed from tracer studies on humans. ► More rudimentary biokinetic models for zinc have been developed in radiation protection. ► Biokinetic data for zinc are reviewed and a new biokinetic model is proposed for radiation protection. ► The proposed model may also be useful for investigation of zinc physiology and homeostasis.

Fishy Business: Effect of Omega-3 Fatty Acids on Zinc Transporters and Free Zinc Availability in Human Neuronal Cells

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Damitha De Mel

2014-08-01

Full Text Available Omega-3 (ω-3 fatty acids are one of the two main families of long chain polyunsaturated fatty acids (PUFA. The main omega-3 fatty acids in the mammalian body are α-linolenic acid (ALA, docosahexaenoic acid (DHA and eicosapentaenoic acid (EPA. Central nervous tissues of vertebrates are characterized by a high concentration of omega-3 fatty acids. Moreover, in the human brain, DHA is considered as the main structural omega-3 fatty acid, which comprises about 40% of the PUFAs in total. DHA deficiency may be the cause of many disorders such as depression, inability to concentrate, excessive mood swings, anxiety, cardiovascular disease, type 2 diabetes, dry skin and so on. On the other hand, zinc is the most abundant trace metal in the human brain. There are many scientific studies linking zinc, especially excess amounts of free zinc, to cellular death. Neurodegenerative diseases, such as Alzheimer’s disease, are characterized by altered zinc metabolism. Both animal model studies and human cell culture studies have shown a possible link between omega-3 fatty acids, zinc transporter levels and free zinc availability at cellular levels. Many other studies have also suggested a possible omega-3 and zinc effect on neurodegeneration and cellular death. Therefore, in this review, we will examine the effect of omega-3 fatty acids on zinc transporters and the importance of free zinc for human neuronal cells. Moreover, we will evaluate the collective understanding of mechanism(s for the interaction of these elements in neuronal research and their significance for the diagnosis and treatment of neurodegeneration.

Fishy business: effect of omega-3 fatty acids on zinc transporters and free zinc availability in human neuronal cells.

Science.gov (United States)

De Mel, Damitha; Suphioglu, Cenk

2014-08-15

Omega-3 (ω-3) fatty acids are one of the two main families of long chain polyunsaturated fatty acids (PUFA). The main omega-3 fatty acids in the mammalian body are α-linolenic acid (ALA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Central nervous tissues of vertebrates are characterized by a high concentration of omega-3 fatty acids. Moreover, in the human brain, DHA is considered as the main structural omega-3 fatty acid, which comprises about 40% of the PUFAs in total. DHA deficiency may be the cause of many disorders such as depression, inability to concentrate, excessive mood swings, anxiety, cardiovascular disease, type 2 diabetes, dry skin and so on. On the other hand, zinc is the most abundant trace metal in the human brain. There are many scientific studies linking zinc, especially excess amounts of free zinc, to cellular death. Neurodegenerative diseases, such as Alzheimer's disease, are characterized by altered zinc metabolism. Both animal model studies and human cell culture studies have shown a possible link between omega-3 fatty acids, zinc transporter levels and free zinc availability at cellular levels. Many other studies have also suggested a possible omega-3 and zinc effect on neurodegeneration and cellular death. Therefore, in this review, we will examine the effect of omega-3 fatty acids on zinc transporters and the importance of free zinc for human neuronal cells. Moreover, we will evaluate the collective understanding of mechanism(s) for the interaction of these elements in neuronal research and their significance for the diagnosis and treatment of neurodegeneration.

[Effect of cultivation in zinc media on the growth of and the degree of zinc in organic form in transgenic metallothionein mushroom].

Science.gov (United States)

Sheng, Ji-Ping; Shen, Lin; Ru, Bing-Gen

2009-03-01

Metallothioneins (MTs) are a family of low molecular weight, cysteine-rich and metal-binding functional proteins. Transgenic MT mushroom can be used as functional food additives, but its zinc-enriching ability has not been studied systemically until now. The zinc contents in mycelia of transgenic MT mushroom (Pleurotus ostreatus) and wild type mushroom mycelia cultivated in different zinc concentration media were analyzed by ICP-OES. The growth status, zinc-enriching ability and degree of zinc in organic form (DZOF) were also analyzed. Results showed that MT mushroom mycelia grew rapidly, but the growth was inhibited when the zinc content in solid media was higher than 1.6 mmol x L(-1). MT mushroom mycelia could enrich more zinc than that of wild type, and the zinc content in MT mushroom mycelia could be 2.56-27.49 mg x kg(-1) when it was cultivated in a liquid media with 0.6-1.2 mmol x L(-1) zinc. DZOF of MT mushroom mycelia in a liquid media with 0.6 mmol x L(-1) zinc at 7 d was significantly higher (88.7%) than that in the wild type (82.1%, alpha = 0.05), but there was no significant difference in DZOF when the MT mushroom mycelia was cultivated in a liquid media with different zinc content at 7 d.

BWR radiation buildup control with ionic zinc

International Nuclear Information System (INIS)

Marble, W.J.; Wood, C.J.; Leighty, C.E.; Green, T.A.

1986-01-01

In 1983 a hypothesis was disclosed which suggested that the presence of ionic zinc in the reactor water of the BWR could reduce radiation buildup. This hypothesis was developed from correlations of plant data, and subsequently, from laboratory experiments which demonstrated clearly that ionic zinc inhibits the corrosion of stainless steel. The benefits of zinc addition have been measured at the Vallecitos Nuclear Center under and EPRI/GE project. Experimentation and analyses have been performed to evaluate the impact of intentional zinc addition on the IGSCC characteristics of primary system materials and on the performance of the nuclear fuel. It has been concluded that no negative effects are expected. The author conclude that the intentional addition of ionic zinc to the BWR reactor water at a concentration of approximately 10 ppb will provide major benefits in controlling the Co-60 buildup on primary system stainless steel surfaces. The intentional addition of zinc is now a qualified technique for use in BWRs

The Limiting Phenomena at the Anode of the Electrowinning of Zinc from Zinc Chloride in a Molten Chloride Electrolyte

NARCIS (Netherlands)

Lans, S.C.

2004-01-01

The objective of this research is to investigate the possibilities and technological viability for the electrowinning of zinc from zinc chloride. This research contributes to development of an alternative process, because it provides: ⢠A clear understanding and overview of the present zinc

Microwave Synthesis of Zinc Hydroxy Sulfate Nanoplates and Zinc Oxide Nanorods in the Classroom

Science.gov (United States)

Dziedzic, Rafal M.; Gillian-Daniel, Anne Lynn; Peterson, Greta M.; Martínez-Herna´ndez, Kermin J.

2014-01-01

In this hands-on, inquiry-based lab, high school and undergraduate students learn about nanotechnology by synthesizing their own nanoparticles in a single class period. This simple synthesis of zinc oxide nanorods and zinc hydroxy sulfate nanoplates can be done in 15 min using a household microwave oven. Reagent concentration, reaction…

Impact of residual elements on zinc quality in the production of zinc oxide

Directory of Open Access Journals (Sweden)

N. Luptáková

2016-07-01

Full Text Available The paper is focused on zinc oxide manufacturing process. The present work deals with the character and morphology of the input material for the production of ZnO by the indirect pyrometallurgical process. Undesirable phases in the feedstock can be identified through profound recognition of the source material and the nature of its microstructure. If these compounds diffuse into the lining during thermal processes, they become the cause of stress in metallurgical ceramics. The emergence of these chemical reactions may subsequently affect the entire metallurgical zinc smelting process. The results obtained by analysis are used to minimize waste - zinc slag and to eliminate the conditions which enable the formation of the undesired product, thereby increasing the productivity of the ZnO production.

The protective nature of passivation films on zinc: surface charge

International Nuclear Information System (INIS)

Muster, Tim H.; Cole, Ivan S.

2004-01-01

The influence of oxide surface charge on the corrosion performance of zinc metals was investigated. Oxidised zinc species (zinc oxide, zinc hydroxychloride, zinc hydroxysulfate and zinc hydroxycarbonate) with chemical compositions similar to those produced on zinc during atmospheric corrosion were formed as particles from aqueous solution, and as passive films deposited onto zinc powder, and rolled zinc, surfaces. Synthesized oxides were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and electron probe X-ray microanalysis. The zeta potentials of various oxide particles, as determined by microelectrophoresis, are reported as a function of pH. Particulates containing a majority of zinc hydroxycarbonate and zinc hydroxysulfate crystallites were found to possess a negative surface charge below pH 6, whilst zinc oxide-hydroxide and zinc hydroxychloride crystallites possessed isoelectric points (IEP's) higher than pH 8. The ability of chloride species to pass through a bed of 3 μm diameter zinc powder was found to increase for surfaces possessing carboxy and sulfate surface species, suggesting that negatively charged surfaces can aid in the repulsion of chloride ions. Electrochemical analysis of the open-circuit potential as a function of time at a fixed pH of 6.5 showed that the chemical composition of passive films on zinc plates influenced the ability of chloride ions to access anodic sites for periods of approximately 1 h

Zinc status in South Asian populations--an update.

Science.gov (United States)

Akhtar, Saeed

2013-06-01

This article attempts to highlight the prevalence of zinc deficiency and its health and economic consequences in South Asian developing countries and to shed light on possible approaches to combating zinc deficiency. A computer-based search was performed on PubMed, Google, and ScienceDirect.com to retrieve relevant scientific literature published between 2000 and 2012. The search yielded 194 articles, of which 71 were culled. Studies were further screened on the basis of population groups, age and sex, pregnancy, and lactation. The most relevant articles were included in the review. Cutoffs for serum zinc concentration defined for zinc deficiency were 65 microg/dL for males and females aged or = 10 years. Population segments from rural and urban areas of South Asian developing countries were included in the analysis. They comprised pregnant and lactating women, preschool and school children. The analysis reveals that zinc deficiency is high among children, pregnant and lactating women in India, Pakistan, Bangladesh, Sri Lanka, and Nepal. Diarrhoea has been established as a leading cause to intensify zinc deficiency in Bangladesh. Little has been done in Sri Lanka and Nepal to estimate the prevalence of zinc deficiency precisely. A substantial population segment of the South Asian developing countries is predisposed to zinc deficiency which is further provoked by increased requirements for zinc under certain physiological conditions. Supplementation, fortification, and dietary diversification are the most viable strategies to enhancing zinc status among various population groups.

Zinc injection helps reduce radiation field buildup in BWRs

International Nuclear Information System (INIS)

Wood, C.

1991-01-01

The injection of zinc into the reactor water of BWRs (Boiling Water Reactors) was a technique developed by General Electric (GE) and the Electric Power Research Institute (EPRI) to control the buildup of radiation fields from cobalt-60 on out-of-core piping. The presence of 5-10ppb zinc in the reactor water reduces the growth of oxide films on stainless steel surfaces, thereby reducing the number of sites available for the incorporation of cobalt; zinc also competes with cobalt for the sites. In September 1990, EPRI organized a workshop at the request of several US utilities to provide a forum to discuss experiences with zinc injection. The meeting focused on six main issues: the effect of zinc on radiation fields in normal water chemistry; the radiation buildup in hydrogen water chemistry, with and without zinc; the effects of zinc-65; the corrosion of fuel cladding and structural materials; the performance of zinc injection and monitoring equipment; and planning for zinc injection. (author)

Recent trends and current practices for secondary processing of zinc and lead. Part II: zinc recovery from secondary sources.

Science.gov (United States)

Sahu, Kamala Kanta; Agrawal, Archana; Pandey, Banshi Dhar

2004-08-01

Almost all metallurgical processes are associated with the generation of wastes and residues that may be hazardous or non-hazardous in nature depending upon the criteria specified by institutions such as the US Environment Protection Agency, etc. Wastes containing heavy and toxic metals such as arsenic, cadmium, chromium, nickel, lead, copper, mercury, zinc, etc., that are present beyond permissible limits deemed to be treated or disposed of, and non-hazardous wastes can be utilized for metal recovery or safe disposal. Zinc is in growing demand all over the world. In India, a major amount of zinc is imported and therefore processing of zinc secondaries will assist in satisfying the gap between demand and supply to some extent. This report mainly focuses on the current practices and recent trends on the secondary processing of zinc. Attempts made by various laboratories to develop ecofriendly processes for the recovery of zinc from secondary raw materials are also described and discussed.

Serum zinc status of neonates with seizure

Directory of Open Access Journals (Sweden)

Olia Sharmeen

2016-08-01

Full Text Available Background: Seizure is a common neurological disorder in neonatal age group!. Primary metabolic derangement is one of the important reason behind this convulsion during this period. Among primary metabolic derangement hypoglycemia, is most common followed by bypocalcaemia, hypomagnesaemia, low zinc status etc. As causes of many cases of convul­sion remain unknown in neonate. Objectives: To see the zinc status in the sera of neonate with convulsion. So that if needed early intervention can be taken up and thereby prevent complications. Method: A total of 50 neonates (1-28 days who had convulsion with no apparent reasons of convulsion were enrolled as cases and 50 healthy age and sex matched neonates were enrolled as controls. After a quick clinical evaluation serum zinc status was estimated from venous blood by atomic absorption method in Chemistry Division, Atomic Energy Centre. Low zinc was considered if serum value was <0.7mg/L. Results: Among a total of 50 cases 6% had low zinc value & 2% of controls also had low zinc level. The mean serwu zinc level of cases and controls were 1.57±0.95 and 2.37±1.06 mmol/1 respectively (p<0.01. Conclusion: From the study it is seen that low zinc value is an important cause of neonatal seizure due to primary metabolic abnormalities. So early recognition and treatment could save these babies from long term neurological sequelies.

Low-temperature solution-processed zinc oxide field effect transistor by blending zinc hydroxide and zinc oxide nanoparticle in aqueous solutions

Science.gov (United States)

Shin, Hyeonwoo; Kang, Chan-mo; Baek, Kyu-Ha; Kim, Jun Young; Do, Lee-Mi; Lee, Changhee

2018-05-01

We present a novel methods of fabricating low-temperature (180 °C), solution-processed zinc oxide (ZnO) transistors using a ZnO precursor that is blended with zinc hydroxide [Zn(OH)2] and zinc oxide hydrate (ZnO • H2O) in an ammonium solution. By using the proposed method, we successfully improved the electrical performance of the transistor in terms of the mobility (μ), on/off current ratio (I on/I off), sub-threshold swing (SS), and operational stability. Our new approach to forming a ZnO film was systematically compared with previously proposed methods. An atomic forced microscopic (AFM) image and an X-ray photoelectron spectroscopy (XPS) analysis showed that our method increases the ZnO crystallite size with less OH‑ impurities. Thus, we attribute the improved electrical performance to the better ZnO film formation using the blending methods.

Critical rate of electrolyte circulation for preventing zinc dendrite formation in a zinc-bromine redox flow battery

Science.gov (United States)

Yang, Hyeon Sun; Park, Jong Ho; Ra, Ho Won; Jin, Chang-Soo; Yang, Jung Hoon

2016-09-01

In a zinc-bromine redox flow battery, a nonaqueous and dense polybromide phase formed because of bromide oxidation in the positive electrolyte during charging. This formation led to complicated two-phase flow on the electrode surface. The polybromide and aqueous phases led to different kinetics of the Br/Br- redox reaction; poor mixing of the two phases caused uneven redox kinetics on the electrode surface. As the Br/Br- redox reaction was coupled with the zinc deposition reaction, the uneven redox reaction on the positive electrode was accompanied by nonuniform zinc deposition and zinc dendrite formation, which degraded battery stability. A single-flow cell was operated at varying electrolyte circulation rates and current densities. Zinc dendrite formation was observed after cell disassembly following charge-discharge testing. In addition, the flow behavior in the positive compartment was observed by using a transparent version of the cell. At low rate of electrolyte circulation, the polybromide phase clearly separated from the aqueous phase and accumulated at the bottom of the flow frame. In the corresponding area on the negative electrode, a large amount of zinc dendrites was observed after charge-discharge testing. Therefore, a minimum circulation rate should be considered to avoid poor mixing of the positive electrolyte.

Influence of ageing on zinc bioavailability in soils

Energy Technology Data Exchange (ETDEWEB)

Lock, K.; Janssen, C.R

2003-12-01

Currently, soil quality criteria or soil risk assessments of metals are based on laboratory toxicity tests which are carried out in soils freshly spiked with metal salts. With these data, species sensitivity distributions are fitted, from which hazardous concentrations and predicted no effect concentrations are derived. However, due to long-term processes, called ageing, soil metal availability decreases with time. Here we show that pH is the most important parameter determining the effect of ageing on zinc partitioning in soils, with the effect of ageing becoming more important with increasing pH. Furthermore, zinc bioavailability, expressed as the internal zinc concentrations in red clover (Trifolium pratense) is closely related to pore water zinc concentration. In addition, there is a clear dose-response relationship between the survival of the earthworm Eisenia fetida and the calcium chloride-extracted zinc fraction. These results indicate that zinc partitioning can be used to predict zinc bioavailability to terrestrial organisms. However, the use of spiked soils in toxicity assays can result in an over-estimation of the effects of zinc, especially at a high pH. - Zn ageing is affected by pH, while Zn partitioning can be used to predict its bioavailability.

Introducing zinc cations into zeolite Y via the reduction of HY with zinc metal vapour

Science.gov (United States)

Seidel, A.; Boddenberg, B.

1996-01-01

Zeolites HY and NaY which were contacted with zinc metal vapour at 420°C were investigated by carbon monoxide and xenon adsorption as well as 129Xe NMR spectroscopy. The reaction of zeolite HY results in the incorporation of Zn 2+ cations which are shown to populate the supercage positions S II and S III to an unusually high extent. The supercage zinc cation concentration strongly decreases when the material is saturated with water and subsequently dehydrated at 400°C. The zeolite NaY turns out to be inert towards the reaction with zinc metal vapour.

Improved electrolyte for zinc-bromine flow batteries

Science.gov (United States)

Wu, M. C.; Zhao, T. S.; Wei, L.; Jiang, H. R.; Zhang, R. H.

2018-04-01

Conventional zinc bromide electrolytes offer low ionic conductivity and often trigger severe zinc dendrite growth in zinc-bromine flow batteries. Here we report an improved electrolyte modified with methanesulfonic acid, which not only improves the electrolyte conductivity but also ameliorates zinc dendrite. Experimental results also reveal that the kinetics and reversibility of Zn2+/Zn and Br2/Br- are improved in this modified electrolyte. Moreover, the battery's internal resistance is significantly reduced from 4.9 to 2.0 Ω cm2 after adding 1 M methanesulfonic acid, thus leading to an improved energy efficiency from 64% to 75% at a current density of 40 mA cm-2. More impressively, the battery is capable of delivering an energy efficiency of about 78% at a current density of as high as 80 mA cm-2 when the electrode is replaced by a thermally treated one. Additionally, zinc dendrite growth is found to be effectively suppressed in methanesulfonic acid supported media, which, as a result, enables the battery to be operated for 50 cycles without degradation, whereas the one without methanesulfonic acid suffers from significant decay after only 40 cycles, primarily due to severe zinc dendrite growth. These superior results indicate methanesulfonic acid is a promising supporting electrolyte for zinc-bromine flow batteries.

Zinc and Regulation of Inflammatory Cytokines: Implications for Cardiometabolic Disease

Science.gov (United States)

Foster, Meika; Samman, Samir

2012-01-01

In atherosclerosis and diabetes mellitus, the concomitant presence of low-grade systemic inflammation and mild zinc deficiency highlights a role for zinc nutrition in the management of chronic disease. This review aims to evaluate the literature that reports on the interactions of zinc and cytokines. In humans, inflammatory cytokines have been shown both to up- and down-regulate the expression of specific cellular zinc transporters in response to an increased demand for zinc in inflammatory conditions. The acute phase response includes a rapid decline in the plasma zinc concentration as a result of the redistribution of zinc into cellular compartments. Zinc deficiency influences the generation of cytokines, including IL-1β, IL-2, IL-6, and TNF-α, and in response to zinc supplementation plasma cytokines exhibit a dose-dependent response. The mechanism of action may reflect the ability of zinc to either induce or inhibit the activation of NF-κB. Confounders in understanding the zinc-cytokine relationship on the basis of in vitro experimentation include methodological issues such as the cell type and the means of activating cells in culture. Impaired zinc homeostasis and chronic inflammation feature prominently in a number of cardiometabolic diseases. Given the high prevalence of zinc deficiency and chronic disease globally, the interplay of zinc and inflammation warrants further examination. PMID:22852057

Erythrocyte zinc levels in children with bronchial asthma.

Science.gov (United States)

Arik Yilmaz, E; Ozmen, S; Bostanci, I; Misirlioglu, E Dibek; Ertan, U

2011-12-01

Zinc deficiency may be suspected to play a role in the pathogenesis, control, and severity of asthma because of its antioxidant, antiapoptotic, and anti-inflammatory effects. We aimed to investigate whether there was any relationship between erythrocyte zinc levels and childhood asthma. The erythrocyte zinc levels of 67 asthmatic and 45 healthy children were analyzed in this case-control study. The mean concentrations of erythrocyte zinc were 1215.8 ± 145.1 µg/dl in asthma patients and 1206.9 ± 119.5 µg/dl in controls with no significant difference (P = 0.472). The erythrocyte zinc level was below 1,000 µg/dl in 6 asthmatic patients (8.9%) and 2 control group patients (4.4%). There was no relationship between erythrocyte zinc levels and duration of follow-up, severity, and control of the asthma (P > 0.05). On the other hand, patients hospitalized for an asthma attack had significantly lower erythrocyte zinc levels compared with nonhospitalized patients and the control group (P = 0.000 and P = 0.004 respectively). This study's findings indicate that asthmatic children are not a risk group for zinc deficiency. We emphasize that checking zinc levels in children who are hospitalized for an asthma attack may be useful. Copyright © 2011 Wiley Periodicals, Inc.

Zinc vanadate nanorods and their visible light photocatalytic activity

International Nuclear Information System (INIS)

Pei, L.Z.; Lin, N.; Wei, T.; Liu, H.D.; Yu, H.Y.

2015-01-01

Highlights: • Zinc vanadate nanorods have been synthesized by a facile hydrothermal process. • The size of zinc vanadate nanorods can be controlled by growth conditions. • Zinc vanadate nanorods show good photocatalytic activities of methylene blue under solar light. - Abstract: Zinc vanadate nanorods have been synthesized by a simple hydrothermal process using zinc acetate and sodium vanadate as the raw materials. The zinc vanadate nanorods have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and solid UV–vis diffuse reflectance spectrum. XRD pattern and HRTEM image show that the zinc vanadate nanorods are composed of single crystalline monoclinic Zn 2 V 2 O 7 phase. SEM and TEM observations show that the diameter and length of the zinc vanadate nanorods are 50–100 nm and about 5 μm, respectively. Sodium dodecyl sulfonate (SDS) has an essential role in the formation of zinc vanadate nanorods. The SDS-assisted nucleation and growth process have been proposed to explain the formation and growth of the zinc vanadate nanorods. Solid UV–vis diffuse reflectance spectrum shows that the zinc vanadate nanorods have a band gap of 2.76 eV. The photocatalytic activities of the zinc vanadate nanorods have been evaluated by the photocatalytic degradation of methylene blue (MB) under solar light irradiation. The MB with the concentration of 10 mg L −1 can be degraded totally under the solar light irradiation for 4 h. It is suggested that the zinc vanadate nanorods exhibit promising application potential for the degradation of organic pollutants under solar light irradiation

Comparative studies on acid leaching of zinc waste materials

Science.gov (United States)

Rudnik, Ewa; Włoch, Grzegorz; Szatan, Leszek

2017-11-01

Three industrial waste materials were characterized in terms of their elemental and phase compositions, leaching behaviour in 10% sulfuric acid solution as well as leaching thermal effects. Slag from melting of mixed metallic scrap contained about 50% Zn and 10% Pb. It consisted mainly of various oxides and oxy-chlorides of metals. Zinc spray metallizing dust contained about 77% Zn in form of zinc and/or zinc-iron oxides, zinc metal and Zn-Fe intermetallic. Zinc ash from hot dip galvanizing was a mixture of zinc oxide, metallic zinc and zinc hydroxide chloride and contained about 80% Zn. Dissolution efficiency of zinc from the first material was 80% (independently on the solid to liquid ratio, 50-150 kg/m3), while decrease of the efficacy from 80% to 60% with increased solid to liquid ratio for the two remaining materials was observed. Both increase in the temperature (20 °C to 35 °C) and agitation rate (300 rpm to 900 rpm) did not improve seriously the leaching results. In all cases, transfer of zinc ions to the leachate was accompanied by different levels of solution contamination, depending on the type of the waste. Leaching of the materials was exothermic with the similar reaction heats for two high oxide-type products (slag, zinc ash) and higher values for the spray metallizing dust.

Neutron-Phonon Interaction Studies in Copper, Zinc and Magnesium Single Crystals; Etude des interactions neutron-phonon dans des monocristaux de cuivre, de zinc et de magnesium; Izuchenie vzaimodejstviya nejtronov i fononov v monokristallakh medi, ninki i magniya; Estudio de las interacciones neutron-fonon en monocristales de cobre, cinc y magnesio

Energy Technology Data Exchange (ETDEWEB)

Maliszewski, E.; Sosnowski, J.; Blinowski, K.; Kozubowski, J.; Padlo, L.; Sledziewska, D. [Institute of Nuclear Research, Warsaw (Poland)

1963-01-15

trouve nettement au-dessus de la courbe de Jacobsen et les points experimentaux signales dans le present memoire confirment les resultats de Cribier er de Jacrot. Les relations de dispersion des phonons dans des monocristaux de zinc et de magnesium ont ete etudiees a l'aide de la methode des neutrons froids et d'un spectrometre neutronique a cristal triaxe, Les auteurs ont trace les surfaces de diffusion dans le plan [1010], trouve les branches AT et AL ainsi que les relations de dispersion des phonons dans les directions [001] et [010] . Us ont compare ces resultats a ceux qu'a obtenus Johnson avec des rayons X . Dans la direction [001] , les resultats s'adaptent bien a la courbe de Johnson en ce qui concerne la branche AL. Dans la direction [010] , pour la branche AT, les auteurs observent un grand ecart entre leurs resultats et ceux de Johnson. 11s en donnent une explication. Ils decrivent des mesures semblables faites a l'heure actuelle dans les memes directions, dans des monocristaux de magnesium. (author) [Spanish] Los autores han estudiado las relaciones de dispersion de fonones en monocristales de cobre con ayuda de un espectrometro neutronico triaxial. En la direccion 100 han observado la rama transversal, no mencionada en las memorias de Cribier y Jacrot. Esta rama concuerda satisfactoriamente con los datos recientes relativos a la velocidad del sonido, pero difiere en parte de los resultados roentgenograncos obtenidos por Jacobsen. En cuanto a la rama longitudinal en la direccion 100, la curva de dispersion obtenida por Cribier y Jacrot se encuentra netamente por encima de la curva de Jacobsen y los puntos experimentales a que se refiere la presente memoria connrman los resultados de Cribier y Jacrot. Los autores han estudiado las relaciones de dispersion de fonones en monocristales de cinc y magnesio por el procedimiento de los neutrones frios, utilizando ademas un espectrometro neutronico triaxial. Han determinado las superficies de dispersion en el plano

Results of zinc injection test for Hamaoka Unit-1

International Nuclear Information System (INIS)

Kani, K.; Masuda, H.; Hayashi, Y.; Sudo, S.; Yamazaki, K.

1998-01-01

A zinc injection test was preformed at Hamaoka Nuclear Power Station Unit-1 for suppressing radiation dose rate on primary coolant recirculation piping after the replacement of piping. Zinc ion was injected by using injection system where Depleted Zinc Oxide was dissolved in carbonated water. Controllability of the system was sufficient to maintain concentration of zinc in primary water. The concentration of zinc in the primary coolant was controlled from 1 ppb to 5 ppb gradually. The increasing trend of concentration of Co-60 in the coolant was suppressed at zinc concentration of 3 ppb. It is evaluated that the deposition coefficient of Co-60 onto the surface of primary coolant recirculation piping was suppressed to one-third of previous cycle in average, and one-fourth of that just before injection start at zinc concentration of 5 ppb. We concluded that zinc injection is effective for suppressing dose rate on the primary coolant piping and no adverse effect occurs by zinc injection up to 5 ppb in the primary coolant. (J.P.N.)

Implication of zinc excess on soil health.

Science.gov (United States)

Wyszkowska, Jadwiga; Boros-Lajszner, Edyta; Borowik, Agata; Baćmaga, Małgorzata; Kucharski, Jan; Tomkiel, Monika

2016-01-01

This study was undertaken to evaluate zinc's influence on the resistance of organotrophic bacteria, actinomyces, fungi, dehydrogenases, catalase and urease. The experiment was conducted in a greenhouse of the University of Warmia and Mazury (UWM) in Olsztyn, Poland. Plastic pots were filled with 3 kg of sandy loam with pHKCl - 7.0 each. The experimental variables were: zinc applied to soil at six doses: 100, 300, 600, 1,200, 2,400 and 4,800 mg of Zn(2+) kg(-1) in the form of ZnCl2 (zinc chloride), and species of plant: oat (Avena sativa L.) cv. Chwat and white mustard (Sinapis alba) cv. Rota. Soil without the addition of zinc served as the control. During the growing season, soil samples were subjected to microbiological analyses on experimental days 25 and 50 to determine the abundance of organotrophic bacteria, actinomyces and fungi, and the activity of dehydrogenases, catalase and urease, which provided a basis for determining the soil resistance index (RS). The physicochemical properties of soil were determined after harvest. The results of this study indicate that excessive concentrations of zinc have an adverse impact on microbial growth and the activity of soil enzymes. The resistance of organotrophic bacteria, actinomyces, fungi, dehydrogenases, catalase and urease decreased with an increase in the degree of soil contamination with zinc. Dehydrogenases were most sensitive and urease was least sensitive to soil contamination with zinc. Zinc also exerted an adverse influence on the physicochemical properties of soil and plant development. The growth of oat and white mustard plants was almost completely inhibited in response to the highest zinc doses of 2,400 and 4,800 mg Zn(2+) kg(-1).

Hemimorphite Ores: A Review of Processing Technologies for Zinc Extraction

Science.gov (United States)

Chen, Ailiang; Li, Mengchun; Qian, Zhen; Ma, Yutian; Che, Jianyong; Ma, Yalin

2016-10-01

With the gradual depletion of zinc sulfide ores, exploration of zinc oxide ores is becoming more and more important. Hemimorphite is a major zinc oxide ore, attracting much attention in the field of zinc metallurgy although it is not the major zinc mineral. This paper presents a critical review of the treatment for extraction of zinc with emphasis on flotation, pyrometallurgical and hydrometallurgical methods based on the properties of hemimorphite. The three-dimensional framework structure of hemimorphite with complex linkage of its structural units lead to difficult desilicification before extracting zinc in the many metallurgical technologies. It is found that the flotation method is generally effective in enriching zinc minerals from hemimorphite ores into a high-grade concentrate for recovery of zinc. Pure zinc can be produced from hemimorphite or/and willemite with a reducing reagent, like methane or carbon. Leaching reagents, such as acid and alkali, can break the complex structure of hemimorphite to release zinc in the leached solution without generation of silica gel in the hydrometallurgical process. For optimal zinc extraction, combing flotation with pyrometallurgical or hydrometallurgical methods may be required.

Serum zinc level in children with malnutrition

International Nuclear Information System (INIS)

Ahmad, T.M.; Mahmood, M.T.; Baluch, G.R.; Bhatti, M.T.

2000-01-01

Serum zinc level amongst children with protein energy malnutrition (PEM) was evaluated in a control study conducted in the Department of Paediatrics, Allama Iqbal Medical College and Jinnah Hospital, Lahore. Twenty-five children with PEM and 25 healthy children as control from the community were screened. Mean serum zinc level was found to be 54.48 -+ 18.91 mg/dl in children with PEM while it was 72.72 -+ 8.21 mg/dl in control group (P < 0.001). No significant difference in zinc level was noted between both sexes in each group. Marasmic 16 children revealed mean serum zinc level of 57.55 -+ 18.16 mg/dl while in Kwashiorkor it was 44.57 -+ 13.66 mg/dl. Serum zinc was significantly low in Kwashiorkor than in marasmus (P < 0.001). It was also significantly low in children with acute or chronic diarrhea associated with malnutrition (44.66 -+ 16.0 mg/dl). Acute respiratory infections in these children were not associated with low serum zinc level (71.66 -+ 16.51 mg/dl). (author)

Effects of the antituberculous drug ethambutol on zinc absorption, turnover and distribution in rats fed diet marginal and adequate in zinc

Energy Technology Data Exchange (ETDEWEB)

King, A.B.; Schwartz, R.