Tuesday, October 21, 2014

 

 



Soy un nuevo usuario

Olvidé mi contraseña

Entrada usuarios

Lógica Matemáticas Astronomía y Astrofísica Física Química Ciencias de la Vida
Ciencias de la Tierra y Espacio Ciencias Agrarias Ciencias Médicas Ciencias Tecnológicas Antropología Demografía
Ciencias Económicas Geografía Historia Ciencias Jurídicas y Derecho Lingüística Pedagogía
Ciencia Política Psicología Artes y Letras Sociología Ética Filosofía
 

rss_1.0 Clasificación por Disciplina

Nomenclatura Unesco > (23) Química

Mostrando recursos 101 - 120 de 41,292

101. Mecanismos de secuestro de carbono en suelos semiáridos en función del tipo de uso y prácticas de manejo= Carbon sequestration mechanisms in semiarid soils according to land use and management practices - García Franco, Noelia
A nivel global se está produciendo una retroalimentación negativa en el ciclo terrestre del carbono con emisiones a la atmosfera de 3-6 Gt/año de CO2. Se estima que más de un 57% de la pérdida del C del reservorio terrestre es debido a la reducción del carbono orgánico del suelo (COS). Aunque, este proceso se puede revertir, mejorando la estructura del suelo a través de usos de suelo y prácticas de manejo sostenibles. Sin embargo, todavía hay necesidad de un mayor conocimiento científico sobre los mecanismos de estabilización del COS y los diferentes factores que intervienen en esa estabilización en...

102. Análise de aflatoxinas B1, G1, B2 e G2 em castanha-do-brasil, milho e amendoim utilizando derivatização pós-coluna no sistema cromatográfico CLAE/ Kobra-Cell®/DFL. - CASTRO, I. M. de; ANJOS, M. R. dos; TEIXEIRA, A. da S.
Neste estudo, foram avaliados e validados métodos para três produtos: a castanha-do-brasil, que envolve uma cadeia produtiva de milhares de pessoas na região norte do país; o milho, que é um item importante da dieta da população brasileira e constitui um dos componentes básicos principais das rações animais; e o amendoim, que é uma importante fonte de óleo e de proteína de alto valor nutricional, usado tanto para fins alimentares como em diversas aplicações na indústria química, farmacêutica, cosmética, entre outras. Considerando o risco associado à presença de aflatoxinas em diferentes cadeias produtivas, torna-se necessário o monitoramento constante destes contaminantes...

103. Química Computacional. Prácticas. Sesiones 1-6 (curso 2014-2015) - Pérez Jiménez, Ángel José
Guiones de las sesiones 1-6 de las prácticas

104. Estudo da interacção de complexos de vanádio com a ca2+-atpase de retículo sarcoplasmático: análise estrutural e funcional - Pereira, Ana Guerreiro
A bomba de cálcio de retículo sarcoplasmático é uma das proteínas mais extensivamente estudadas, capaz de interagir com várias espécies e compostos de vanádio. Combinando-se estudos de fluorescência com ensaios cinéticos de transporte e ligação de 45Ca à ATPase, avaliou-se o efeito de três complexos de vanádio na função bioenergética e estrutural de Ca2+-ATPase. Demonstrou-se que concentrações próximas dos valores de IC50 (para a hidrólise de ATP) de BMOV-V(IV) e de PDC-V(V) não inibem significativamente a acumulação de 45Ca por sarcovesículas. Por outro lado, o complexo PDC-V(V) mostrou ser capaz de estimular a ligação de 45Ca ao retículo sarcoplasmático, sugerindo que...

105. Formación y caracterización de emulsiones altamente concentradas de betún en agua - Martínez Rodríguez, María
Tesi realitzada a l'Institut de Química Avançada de Catalunya (CSIC)

106. SAF's + 10 sistemas agroflorestais e desenvolvimento sustentável: 10 anos de pesquisa.
Acúmulo de Forragem do Capim-Braquiária Consorciado com Leguminosas e Banco de Proteína, com Adubação e Calagem; Alterações dos Atributos Químicos de um Neossolo Quartzarênico em Relação ao Sistema de Uso e Manejo; 3- Atributos Biométricos e Teor de Extrato Etéreo de Acessos de Pequi (Caryocar spp.) e Viabilidade de Cultivo; Atributos Físicos de Um Neossolo Quartzarênico em Diferentes Sistemas de Manejo e Uso do Solo; Atributos Químicos do Solo em Sistema Silvipastoril de Eucalyptus e Brachiaria brizantha cv. Marandu; Avaliação da Produção do Milho (Zea mays L.) em Sistema Agropastoril em Diferentes Sistemas de Manejo do Solo; Biomassa da Parte...

107. Indoor environmental quality and infection control in surgery rooms: code requirements vs. performance motivation. A critical review - Cubí Montanyà, Eduard; Salom Tormo, Jaume; Garrido Soriano, Núria
Surgery rooms are a space type with particularly stringent indoor environmental quality (IEQ) requirements (large airflow rates and narrow comfort windows), which translate into high energy use. Due to the unclear IEQ and infection control requirements for surgery rooms in Spain, these spaces are often designed and operated 24 hours per day and 7 days per week, to meet the most stringent recommendations (not only the requirements) in the available standards and guidelines. This paper critically reviews the Spanish mandatory requirements for surgery rooms by comparing them against their performance motivation and other international standards. Regulatory ambiguities and code-compliant energy...

108. Indoor environmental quality and infection control in surgery rooms: code requirements vs. performance motivation. A critical review - Cubí Montanyà, Eduard; Salom Tormo, Jaume; Garrido Soriano, Núria
Surgery rooms are a space type with particularly stringent indoor environmental quality (IEQ) requirements (large airflow rates and narrow comfort windows), which translate into high energy use. Due to the unclear IEQ and infection control requirements for surgery rooms in Spain, these spaces are often designed and operated 24 hours per day and 7 days per week, to meet the most stringent recommendations (not only the requirements) in the available standards and guidelines. This paper critically reviews the Spanish mandatory requirements for surgery rooms by comparing them against their performance motivation and other international standards. Regulatory ambiguities and code-compliant energy...

109. Sulfonated poly(ether ether ketone) as an alternative charged material to poly(vinyl chloride) in the design of ion-selective electrodes - González Bellavista, Anna; Macanàs de Benito, Jorge; Muñoz Tapia, Maria; Fábregas Martínez, Esteve
To date, poly(vinyl chloride) (PVC) is the most used polymer in the design of ion selective electrode (ISE) membranes. This paper is focused on the use of sulfonated poly(ether ether ketone) (SPEEK) as an alternative material to PVC for the design of ISEs. SPEEK of the desired degree of sulfonation is synthesized from poly(ether ether ketone) (PEEK). An NH4+-ISE has been chosen as a model electrode to study the efficiency of SPEEK as polymer matrix of the membrane. The material was evaluated in ionophore free ion exchanger membranes as well as in ion-selective electrodes membranes containing nonactine as ionophore. Analytical...

110. Sulfonated poly(ether ether ketone) as an alternative charged material to poly(vinyl chloride) in the design of ion-selective electrodes - González Bellavista, Anna; Macanàs de Benito, Jorge; Muñoz Tapia, Maria; Fábregas Martínez, Esteve
To date, poly(vinyl chloride) (PVC) is the most used polymer in the design of ion selective electrode (ISE) membranes. This paper is focused on the use of sulfonated poly(ether ether ketone) (SPEEK) as an alternative material to PVC for the design of ISEs. SPEEK of the desired degree of sulfonation is synthesized from poly(ether ether ketone) (PEEK). An NH4+-ISE has been chosen as a model electrode to study the efficiency of SPEEK as polymer matrix of the membrane. The material was evaluated in ionophore free ion exchanger membranes as well as in ion-selective electrodes membranes containing nonactine as ionophore. Analytical...

111. Polysulfone as an alternative material to PVC in the design of ion-selective electrodes - González Bellavista, Anna; Macanàs de Benito, Jorge; Muñoz Tapia, Maria; Fábregas Martínez, Esteve
Polysulfone (PS), a non-conductive polymer, is employed as an alternative material to polyvinyl chloride (PVC), the most used polymer in the design of ion-selective electrode (ISE) membranes to date. A nitrate-ISE is chosen as a model electrode to study the efficiency of PS as a polymer matrix of the membrane. Tetra-octyl ammonium nitrate is used as ionophore and 2-nitrophenyl octyl ether as plasticizer. The polymer/plasticizer/ionophore ratio is optimized and the analytical performance parameters of the prepared electrodes are evaluated. The electrodes show a slope between 45 and 60 mV/decade (depending on the calibration medium and membrane composition). A linear range response...

112. Polysulfone as an alternative material to PVC in the design of ion-selective electrodes - González Bellavista, Anna; Macanàs de Benito, Jorge; Muñoz Tapia, Maria; Fábregas Martínez, Esteve
Polysulfone (PS), a non-conductive polymer, is employed as an alternative material to polyvinyl chloride (PVC), the most used polymer in the design of ion-selective electrode (ISE) membranes to date. A nitrate-ISE is chosen as a model electrode to study the efficiency of PS as a polymer matrix of the membrane. Tetra-octyl ammonium nitrate is used as ionophore and 2-nitrophenyl octyl ether as plasticizer. The polymer/plasticizer/ionophore ratio is optimized and the analytical performance parameters of the prepared electrodes are evaluated. The electrodes show a slope between 45 and 60 mV/decade (depending on the calibration medium and membrane composition). A linear range response...

113. Atomic force microscopy as a suitable technique for surface characterization of activated composite membranes for metal ion facilitated transport - Macanàs de Benito, Jorge; Palacio Martínez, Laura; Prádanos del Pico, Pedro; Hernández Giménez, Antonio; Muñoz Tapia, Maria
Activated composite membranes (ACM) have been made based on a polysulfone layer over a non-woven support with a dense layer of aromatic polyamide, and deposited on the polysulfone using interfacial polymerisation by a carrier agent – di(2-ethylhexyl) dithiophosphoric acid – added to the membranes at several concentrations. Two polysulfone supports have been used, one of them commercial (PSf-Com) an other made ad hoc by us (PSf-GTS). The membrane structure has been characterised by both atomic force microscopy (AFM) and scanning electron microscopy (SEM). Firstly, the two polysulfonic bases were studied. The results show that structurally both are quite similar. PSf-Com presents...

114. Atomic force microscopy as a suitable technique for surface characterization of activated composite membranes for metal ion facilitated transport - Macanàs de Benito, Jorge; Palacio Martínez, Laura; Prádanos del Pico, Pedro; Hernández Giménez, Antonio; Muñoz Tapia, Maria
Activated composite membranes (ACM) have been made based on a polysulfone layer over a non-woven support with a dense layer of aromatic polyamide, and deposited on the polysulfone using interfacial polymerisation by a carrier agent – di(2-ethylhexyl) dithiophosphoric acid – added to the membranes at several concentrations. Two polysulfone supports have been used, one of them commercial (PSf-Com) an other made ad hoc by us (PSf-GTS). The membrane structure has been characterised by both atomic force microscopy (AFM) and scanning electron microscopy (SEM). Firstly, the two polysulfonic bases were studied. The results show that structurally both are quite similar. PSf-Com presents...

115. Examining thiosulfate-driven autotrophic denitrification through respirometry - Mora, Mabel; Guisasola, Albert; Gamisans Noguera, Javier; Gabriel Buguña, David
Anoxic respirometry was applied to characterize a sulfide-oxidizing nitrate-reducing (SO-NR) culture obtained from an anoxic biogas desulfurizing biotrickling filter treating high loads of H2S. Immobilized biomass extracted from the biotrickling filter was grown in a suspended culture with thiosulfate as electron donor to obtain the biomass growth yield and the S2O32-/NO3- consumed ratio. Afterward, respirometry was applied to describe thiosulfate oxidation under anoxic conditions. A pure culture of Thiobacillus denitrificans was also used as a control culture in order to validate the procedure proposed in this work to characterize the SO-NR biomass. Respirometric profiles obtained with this microbial culture showed...

116. Examining thiosulfate-driven autotrophic denitrification through respirometry - Mora, Mabel; Guisasola, Albert; Gamisans Noguera, Javier; Gabriel Buguña, David
Anoxic respirometry was applied to characterize a sulfide-oxidizing nitrate-reducing (SO-NR) culture obtained from an anoxic biogas desulfurizing biotrickling filter treating high loads of H2S. Immobilized biomass extracted from the biotrickling filter was grown in a suspended culture with thiosulfate as electron donor to obtain the biomass growth yield and the S2O32-/NO3- consumed ratio. Afterward, respirometry was applied to describe thiosulfate oxidation under anoxic conditions. A pure culture of Thiobacillus denitrificans was also used as a control culture in order to validate the procedure proposed in this work to characterize the SO-NR biomass. Respirometric profiles obtained with this microbial culture showed...

117. Coupling respirometry and titrimetry for the characterization of the biological activity of a SO-NR consortium - Mora, Mabel; Lopez, Luis R.; Gamisans Noguera, Javier; Gabriel Buguña, David
Determining growth rates and kinetic mechanisms of microbial consortia often needs of combining several tests and techniques. The present work demonstrates that combining titrimetric and respirometric data obtained in a single batch test allows obtaining the stoichiometric coefficients, biomass-substrate yields and biological oxidation rates for sulfide-oxidizing nitrate-reducing consortia obtained from an anoxic biotrickling filter for biogas desulfurization. Thiosulfate oxidation using either nitrate or nitrite was quantified as well as the biological production of proton linked to the process to solve the stoichiometry of the two-step autotrophic denitrification associated to thiosulfate oxidation. To obtain accurate titrimetric data related to the biological...

118. Coupling respirometry and titrimetry for the characterization of the biological activity of a SO-NR consortium - Mora, Mabel; Lopez, Luis R.; Gamisans Noguera, Javier; Gabriel Buguña, David
Determining growth rates and kinetic mechanisms of microbial consortia often needs of combining several tests and techniques. The present work demonstrates that combining titrimetric and respirometric data obtained in a single batch test allows obtaining the stoichiometric coefficients, biomass-substrate yields and biological oxidation rates for sulfide-oxidizing nitrate-reducing consortia obtained from an anoxic biotrickling filter for biogas desulfurization. Thiosulfate oxidation using either nitrate or nitrite was quantified as well as the biological production of proton linked to the process to solve the stoichiometry of the two-step autotrophic denitrification associated to thiosulfate oxidation. To obtain accurate titrimetric data related to the biological...

119. La ciclosporina A produce anión superóxido intracelular en el endotelio - Navarro-Antolín, J.; Lamas, Santiago
Muchas enfermedades están asociadas con una sobreproducción de radicales libres del oxígeno generadores de daño celular. Entre estos radicales, el anión superóxido ha recibido especial atención por su participación en patologías con alta prevalencia, como por ejemplo, el daño por reperfusión (tras infarto miocárdico o accidente cerebrovascular) o los procesos inflamatorios como la artritis. La importancia del anión superóxido en términos de utilidad terapéutica queda reflejado en el esfuerzo, culminado ya al menos en animales1, por encontrar agentes mimetizadores de la actividad superóxido dismutasa (eliminación de anión superóxido) con estabilidad química y biológica in vivo. Hasta ahora se ha considerado que los efectos...

120. Santiago Ramón y Cajal sobre el problema de la conciencia - Currás Puente, Emilia; Wulff, Enrique
[EN] Santiago Ramón y Cajal (1852-1934) stressed the significance of the relation between the brain and the mind through the patterning of consciousness during brain development. There are levels of nervous activity and no real hint of Cajal identifying the language as a first structure. Cajal’s deductions on cerebral localization makes his research relevant to the doctrine of the seat of the soul. He viewed the integration of the intelligence and the emotions in the organ of consciousness by way of the innate brain’s architecture excellence. He engaged on pathological and physiological chemical researches to promote and improve the regeneration...

Página de resultados:
 

Busque un recurso