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Immobilization of glucose oxidase enzyme (GOD) in large pore ordered mesoporous cage-like FDU-1 silica

Silva, Luis Carlos Cides da; INFANTE, C. M. C.; LIMA, A. W. O.; COSENTINO, I. C.; Fantini, Marcia Carvalho de Abreu; ROCHA, F. R. P.; MASINI, J. C.; MATOS, J. R.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
35.83%
Large pore ordered mesoporous silica FDU-1 with three-dimensional (3D) face-centered cubic, Fm3m arrangement of rnesopores, was synthesized under strong acid media using B-50-6600 poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide) triblock copolymer (EO(39)BO(47)EO(39)), tetraethyl orthosilicate (TEOS) and trimethyl-benzene (TMB). Large pore FDU-1 silica was obtained by using the following gel composition 1TEOS:0.00735B50-6600:0.00735TMB:6HCl:155H(2)O. The pristine material exhibited a BET specific surface area of 684 m(2) g(-1), total pore volume of 0.89 cm(3) g(-1), external surface area of 49 m(2) g(-1) and microporous volume of 0.09 cm(3) g(-1). The enzyme activity was determined by the Flow Injection Analysis-Chemiluminescence (FIA-CL) method. For GOD immobilized on the FDU-1 silica, GOD supernatant and GOD solution, the FIA-CL results were 9.0, 18.6 and 34.0 U, respectively. The value obtained for the activity of the GOD solution with FIA-CL method is in agreement with the 35 U, obtained by spectrophotometry. (C) 2011 Elsevier B.V. All rights reserved.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); FAPESP[2007/07646-2]; FAPESP[2008/09284-3]; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); CNPq; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); CAPES; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Metodologias para determinação de fármacos, metabólitos e disruptores endócrinos em água de abastecimento público utilizando técnicas de separação em meio líquido (CE/UV, CE-MS, LC-MS/MS); Methods for determination of pharmaceuticals, their metabolites and endocrine disruptors in surface water using separation techniques in liquid media (CE/UV, CE-MS, HPLC-MS/MS)

Costa, Ana Carolina de Oliveira
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 03/12/2009 PT
Relevância na Pesquisa
36.03%
Este trabalho apresenta o desenvolvimento e validação de métodos analíticos para investigar a presença de fármacos e seus metabólitos, assim como disruptores endócrinos, em amostras de águas superficiais, utilizando estratégias de "clean up" e enriquecimento de amostra no modo "on line" ("stacking") e "off line" (extração em fase sólida, SPE), em junção com técnicas de separação avançadas em meio líquido (eletroforese capilar, CE, e cromatografia a líquido, LC, com detecção UV, e seus acoplamentos com espectrometria de massas). No primeiro Capítulo são discutidos aspectos gerais sobre os produtos farmacêuticos, produtos de higiene pessoal e disruptores endócrinos, bem como a origem e ocorrência destas substâncias no meio ambiente. O segundo Capítulo aborda o desenvolvimento de um método de separação capaz de determinar oito substâncias entre fármacos de caráter ácido e metabólitos (diclofenaco, bezafibrato, fenoprofeno, ibuprofeno, cetoprofeno, naproxeno e ácidos gentísico e salicílico) numa única corrida, utilizando eletroforese capilar com enriquecimento em linha da amostra (stacking do analito baseado em grande volume de injeção da amostra) utilizando eletrólito de corrida constituído por 30 mmol L-1 de tetraborato de sódio e 5 mmol L-1 de Brij 35...

Estudo e caracterização de dispositivos fotovoltaicos orgânicos (OPV) baseados em heterojunção de volume; Study and characterization of organic photovoltaic devices (OPV) based on bulk heterojunction

Coutinho, Douglas José
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 26/07/2011 PT
Relevância na Pesquisa
35.73%
Um dos grandes desafios do século XXI está na produção de energia limpa e renovável, já que a demanda mundial por energia continuará crescendo, assim como a necessidade de despoluir o planeta e de diminuir a emissão dos gases do efeito estufa. Nesse contexto, a conversão de energia solar em elétrica coloca-se como uma excelente alternativa, e com isso a dos dispositivos fotovoltaicos. A tecnologia fotovoltaica baseada no silício e em outros semicondutores orgânicos encontra-se em estágio relativamente avançado, porém o custo de produção e de manutenção a proíbe em uso de grande escala. Mais recentemente, iniciaram-se pesquisas com filmes de semicondutores orgânicos, e a rápida melhora na performance dessas células solares a coloca como promissora ao mercado fotovoltaico. Em nosso trabalho, realizamos estudos sobre a performance de dispositivos fotovoltaicos orgânicos baseados na estrutura de heterojunção, estudando a influência de vários parâmetros na performance dos dispositivos. Usamos como camada ativa para nossos dispositivos o poli(3-hexiltiofeno) (P3HT) regiorregular, que é um polímero condutor de gap eletrônico em torno de 1,8 eV misturado ao [6,6]-fenil-C61-ácido butírico-metil ester (PCBM). Essa mistura é apropriada à dissociação dos éxcitons gerados nas cadeias poliméricas pelos fótons absorvidos porque...

Soluções Parenterais de Grande Volume: avaliação da estabilidade da solução e qualidade física e química da embalagem primária; Large Volume Parenteral Solutions: evaluation of the stability of the solution and physical and chemical quality of the primary packing

Bassi, Ana Claudia Zampronio
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 04/05/2012 PT
Relevância na Pesquisa
55.84%
As Soluções Parenterais de Grande Volume (SPGV´s) são definidas como solução estéril e apirogênica destinada à aplicação parenteral em dose única, na qual o plástico é o material de acondicionamento primário utilizado. O presente trabalho teve como objetivo avaliar as características físico-químicas e microbiológicas da solução fisiológica de cloreto de sódio 0,9% (m/v), bem como as propriedades químicas e físicas da embalagem primária. Foram utilizadas amostras de solução injetável de cloreto de sódio 0,9% m/v de 500 mL em diferentes apresentações comerciais e tipo de embalagem primária (Grupos A, B, C e D), após armazenamento em câmara climática. Foi realizada avaliação físico-química e microbiológica da solução contida nas diferentes embalagens, antes e após armazenamento de 90 e 180 dias em câmara climática, mantida a temperatura de 40ºC e umidade relativa de 25% conforme estabelecido pela International Conference on Harmonisation (ICH) e 75%, conforme preconizado pela Agência Nacional de Vigilância Sanitária (ANVISA). Realizou-se a determinação dos ensaios químicos e físicos para a embalagem primária em contato com a solução. Além disso, foram avaliados os cuidados de conservação das SPGV´s em instituições hospitalares. Verificou-se a influência da umidade relativa (UR) nas taxas de permeabilidade ao vapor de água...

Development of novel approaches for micro-extraction: application of microfluidic devices and novel sorption-based polymers

Mourão, Marta Pacheco Botelho
Fonte: Universidade de Lisboa Publicador: Universidade de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2012 ENG
Relevância na Pesquisa
35.7%
Tese de mestrado em Química Analítica, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2012; O presente trabalho inclui duas partes distintas, tendo como objetivos desenvolver e aplicar novas abordagens de micro-extração para análise vestigial usando dispositivos microfluídicos e polímeros inovadores baseados em sorção. Na primeira parte, estudaram-se, no modo dinâmico, dispositivos microfluídicos (“chips”) com diferentes tamanhos e geometrias, tendo o desempenho sido avaliado relativamente a taxas de fluxo, volume de amostra, repetibilidade e eficiência usando a dessorção líquida (LD). Os dispositivos foram posteriormente aplicados na extração de ácidos gordos metilados, tolueno, xileno, etilbenzeno e benzeno e hidrocarbonetos aromáticos policíclicos, utilizados como compostos modelo em soluções aquosas, seguido de cromatografia em fase gasosa com deteção por ionização de chama (GC-FID). A forma linear e empacotada com partículas de PDMS [(10.4 ± 0.10) mg], apresentou resultados adequados com boa repetibilidade (RSD≤15 %) e eficiência (75-93 %). No entanto, devido à dificuldade de empacotamento das partículas de PDMS, a aplicação da metodologia a matrizes aquosas, em particular água superficial...

Aplicação de espumas de poliuretano em técnicas de micro-extracção analítica

Silva, Isabela Marina Baía Magalhães da
Fonte: Universidade de Lisboa Publicador: Universidade de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2013 POR
Relevância na Pesquisa
35.77%
Tese de mestrado em Química, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2013; O presente trabalho propõe um novo conceito para micro-extração estática, no qual espumas de poliuretano (PU) são usadas como fases para sorção-dessorção, aproveitando-se as excelentes propriedades sortivas e mecânicas que evidenciam. Esta nova abordagem designada por micro-extração em PU (PUμE), consiste no uso de espumas com geometria cilíndrica embebidas com solventes orgânicos adequados e operando através da tecnologia de amostragem por flutuação, seguida de dessorção líquida por compressão mecânica com recurso a seringa e análise por cromatografia em fase gasosa com injeção de grandes volumes acoplada à espetrometria de massa operando no modo de monitorização de iões selecionados (LVI-GC-MS(SIM)). Para o presente estudo selecionaram-se três fungicidas (metalaxyl-M, penconazole e tebuconazole) como compostos modelo no sentido de avaliar o desempenho desta nova metodologia em matrizes aquosas. Numa primeira fase desenvolveu-se e otimizou-se o passo de micro-extração, nomeadamente, o tipo de solvente orgânico e o volume embebido na fase de PU, mas também o passo de retro-extração, nomeadamente...

Overcoming the schlieren effect in flow injection spectrophotometry by introduction of large sample volumes: determination of chloride in the electrolyte of lead-acid batteries

Rocha,Fábio R.P.; Nóbrega,Joaquim A.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/1997 EN
Relevância na Pesquisa
35.78%
A flow injection spectrophotometric system is proposed for determining chloride in lead-acid battery electrolyte by using the displacement reaction between mercury(II) thiocyanate and chloride in a medium containing iron(III). The employment of a large sample volume was effective to avoid refractive index gradients in the central part of the sample zone. Sulfate interference was studied and the correlation between the chemical equilibria involved and the transient signals was used to develop a strategy for chloride quantification. Samples containing from 2.2 to 3.7 mol L-1 of sulfuric acid can be determined by using the same analytical curve, without matrix interference or any previous treatment. The detection limit and the relative standard deviation were estimated in 0.37 mg Cl- L-1 (99.7% confidence level) and 1.6% (n = 10), respectively. The sampling rate was 45 h-1. Recoveries between 95.9 and 108% were obtained for additions of chloride (2.00 to 8.00 mg L-1) in the samples.

A Pharmacokinetic Study of Amphotericin B Lipid Complex Injection (Abelcet) in Patients with Definite or Probable Systemic Fungal Infections

Adedoyin, Adedayo; Swenson, Christine E.; Bolcsak, Lois E.; Hellmann, Andrzej; Radowska, Danuta; Horwith, Gary; Janoff, Andrew S.; Branch, Robert A.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /10/2000 EN
Relevância na Pesquisa
35.67%
This study describes a pharmacokinetic evaluation of amphotericin B (AMB) lipid complex injection (ABLC or Abelcet) in 17 patients with systemic fungal infection administered 5 mg/kg of body weight/day by infusion for 10 to 17 days. The results showed that AMB exhibited multiexponential disposition with high clearance, large volume of distribution at steady state, and long apparent elimination half-life but no evidence of accumulation in the blood after multiple daily doses. The results confirm previous observations and further reinforce the suggestion that ABLC may exist as a depot in the tissues from which free AMB is slowly released to limit exposure.

Quantitative Determination of Fluorinated Alkyl Substances by Large-Volume-Injection LC/MS/MS—Characterization of Municipal Wastewaters

Schultz, Melissa M.; Barofsky, Douglas F.; Field, Jennifer A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/01/2006 EN
Relevância na Pesquisa
65.81%
A quantitative method was developed for the determination of fluorinated alkyl substances in municipal wastewater influents and effluents. The method consisted of centrifugation followed by large-volume injection (500 μL) of the supernatant onto a liquid chromatograph with a reverse-phase column and detection by electrospray ionization, and tandem mass spectrometry (LC/MS/MS). The fluorinated analytes studied include perfluoroalkyl sulfonates, fluorotelomer sulfonates, perfluorocarboxylates, and select fluorinated alkyl sulfonamides. Recoveries of the fluorinated analytes from wastewater treatment plant (WWTP) raw influents and final effluent ranged from 77% – 96% and 80% – 99%, respectively. The lower limit of quantitation ranged from 0.5 to 3.0 ng/L depending on the analyte. The method was applied to flow-proportional composites of raw influent and final effluent collected over a 24 hr period from ten WWTPs nationwide. Fluorinated alkyl substances were observed in wastewater at all treatment plants and each plant exhibited unique distributions of fluorinated alkyl substances despite similarities in treatment processes. In nine out of the ten plants sampled, at least one class of fluorinated alkyl substances exhibited increased concentrations in the effluent as compared to the influent concentrations. In some instances...

Parametric evaluation for programmable temperature vaporization large volume injection in gas chromatographic determination of polybrominated diphenyl ethers

Wei, Hua; Dassanayake, Priyanthi S.; Li, An
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/01/2010 EN
Relevância na Pesquisa
65.99%
This work is a thorough investigation on the major operating parameters of the programmable temperature vaporization (PTV) inlet used for gas chromatographic injection, including injection mode and volume, inlet temperature, vent and purge flow rates. The results clearly demonstrate the advantage of large volume injection in enhancing the detection of polybrominated diphenyl ethers (PBDEs). Partial loss of injected PBDEs occurred during solvent venting and due to incomplete sample transfer. Such loss was minimized by lowering the initial inlet temperature and vent flow and elevating the final inlet temperature. The results show that 50 mL/min vent flow, as low as 0 °C initial and higher than 300 °C final inlet temperatures produced the relatively high responses. Two mass spectrometric parameters were also evaluated. Indoor dust, lake sediment and human placenta tissue samples were analyzed to demonstrate reliability and sensitivity improvement of the PTV large volume injection.

Photodegradation of Fleroxacin Injection: Different Products with Different Concentration Levels

Wang, Jun; Li, Wei; Li, Chen-Gui; Hu, Yu-Zhu
Fonte: Springer US Publicador: Springer US
Tipo: Artigo de Revista Científica
Publicado em 30/06/2011 EN
Relevância na Pesquisa
45.85%
Photodegradation of fleroxacin is investigated in different injections and solutions. After UV irradiation, fleroxacin was degraded to afford two major products in large-volume injection (specification, 200 mg:100 ml), while degraded to afford another major product in small-volume injection (specification, 200 mg:2 ml). The photodegradation products were detected and isolated by reversed-phase HPLC. Based on the spectral data (FT-IR, MSn, TOF-MS, 1H/13C, DEPT, and 2D NMR), the structures of these products were: 8-fluoro-9-(4-methyl-piperazin-1-yl)-6-oxo-2,3-dihydro-6H-1-oxa-3a-aza-phenalene-5-carboxylic acid (impurity-I); 6-fluoro-1-(2-fluoro-ethyl)-7-(2-methylamino-ethylamino)-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid (impurity-II); and 6,8-difluoro-1-(2-fluoro-ethyl)-7-(2-methylamino-ethylamino)-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid (impurity-III), respectively. Different photodegradation pathways of fleroxacin were proposed, which led to the different stability characteristics of fleroxacin in the injections. The fluorine atom at C8 is more photolabile in dilute injection, so defluorination and cyclization reactions are prone to take place, whereas photo irradiation only cause ring-opening oxidation reaction of piperazine side chain in concentrated injection.

Analysis of Androgenic Steroids in Environmental Waters by Large-volume Injection Liquid Chromatography Tandem Mass Spectrometry

Backe, Will J.; Ort, Christoph; Brewer, Alex J.; Field, Jennifer A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
65.81%
A new method was developed for the analysis of natural and synthetic androgenic steroids and their selected metabolites in aquatic environmental matrices using direct large-volume injection (LVI) high performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS). Method accuracy ranged from 88 to 108% for analytes with well-matched internal standards. Precision, quantified by relative standard deviation (RSD), was less than 12%. Detection limits for the method ranged from 1.2 to 360 ng/L. The method was demonstrated on a series of 1-hr composite wastewater influent samples collected over a day with the purpose of assessing temporal profiles of androgen loads in wastewater. Testosterone, androstenedione, boldenone, and nandrolone were detected in the sample series at concentrations up to 290 ng/L and loads up to 535 mg. Boldenone, a synthetic androgen, had a temporal profile that was strongly correlated to testosterone, a natural human androgen, suggesting its source may be endogenous. An analysis of the sample particulate fraction revealed detectable amounts of sorbed testosterone and androstenedione. Androstenedione sorbed to the particulate fraction accounted for an estimated five to seven percent of the total androstenedione mass.

Condensation of Plasmid DNA Enhances Mitochondrial Association in Skeletal Muscle Following Hydrodynamic Limb Vein Injection

Yasuzaki, Yukari; Yamada, Yuma; Fukuda, Yutaka; Harashima, Hideyoshi
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 21/08/2014 EN
Relevância na Pesquisa
35.79%
Mitochondrial gene therapy and diagnosis have the potential to provide substantial medical benefits. However, the utility of this approach has not yet been realized because the technology available for mitochondrial gene delivery continues to be a bottleneck. We previously reported on mitochondrial gene delivery in skeletal muscle using hydrodynamic limb vein (HLV) injection. HLV injection, a useful method for nuclear transgene expression, involves the rapid injection of a large volume of naked plasmid DNA (pDNA). Moreover, the use of a condensed form of pDNA enhances the nuclear transgene expression by the HLV injection. The purpose of this study was to compare naked pDNA and condensed pDNA for mitochondrial association in skeletal muscle, when used in conjunction with HLV injection. PCR analysis showed that the use of condensed pDNA rather than naked pDNA resulted in a more effective mitochondrial association with pDNA, suggesting that the physicochemical state of pDNA plays a key role. Moreover, no mitochondrial toxicities in skeletal muscle following the HLV injection of condensed pDNA were confirmed, as evidenced by cytochrome c oxidase activity and mitochondrial membrane potential. These findings have the potential to contribute to the development for in vivo mitochondrial gene delivery system.

Compound-specific isotope analysis to delineate the sources and fate of organic contaminants in complex aquifer systems; Komponentenspezifische Isotopenanalyse zur Aufklärung der Herkunft und des Verbleibs von organischen Schadstoffen in komplexen Grundwasserleitern

Blessing, Michaela
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
EN
Relevância na Pesquisa
35.91%
The extensive use of organic compounds has frequently caused soil and groundwater contamination. Volatile organic compounds, such as chlorinated and aromatic hydrocarbons and the semi-volatile polycyclic aromatic hydrocarbons are among the most widespread organic pollutants. The fate and behavior of such compounds in the subsurface depend on a number of physicochemical and biological processes, which may lead to ‘natural attenuation’. For the consideration of these in-situ contaminant-reducing processes as a valid remedial approach, it is necessary to attain an appropriate understanding of the key processes occurring in natural aquifers. Compound-specific isotope analysis (CSIA) with on-line gas chromatography-isotope ratio mass spectrometry (GC/IRMS) offers a versatile tool for the characterization of origin and fate of organic contaminants in environmental analytical chemistry. The aim of the present work was to evaluate and demonstrate the potential and limitations of CSIA for studying sources and fate of organic contaminants at heterogeneous and complex aquifer systems. One major drawback in the application of CSIA to field studies, is that current GC/IRMS systems are limited in their sensitivity. To overcome this limitation and to enhance method detection limits...

Use of a Temperature-programmable Injector Coupled to Gas Chromatography-combustion-isotope Ratio Mass Spectrometry for Compound-specific Carbon Isotopic Analysis of Polycyclic Aromatic Hydrocarbons

MIKOLAJCZUK Agnieszka; GEYPENS Benny; BERGLUND Michael; TAYLOR Philip
Fonte: JOHN WILEY & SONS LTD Publicador: JOHN WILEY & SONS LTD
Tipo: Contributions to Conferences Formato: Printed
ENG
Relevância na Pesquisa
35.92%
Compound Specific Isotopic Analysis (CSIA) can provide information about the origin of analyzed compounds for instance polycyclic aromatic hydrocarbons (PAHs) in aerosols. This could be a valuable tool in source apportionment of particulate matter (PM) air pollution. Because gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) analysis requires an amount of at least 10 ng of an individual PAH, a high concentration of PAHs in the injected extract is needed. When the concentration is low a large volume injector creates the possibility of introducing a satisfactory amount of individual PAHs. In this study the temperature programmable injector was coupled to GC-C-IRMS and injection parameters (solvent level, transfer column flow, transfers time) were optimized using six solid aromatic compounds (anthracene, fluoranthene, pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene) dissolved in n-pentane and EPA 610 reference mixture. Solid PAHs CSIA results were compared to results obtained for the single components analysed with elemental analysis - isotope ratio mass spectrometry. The injection method was validated for two sample injection volumes, 50 and 100 µL. This method was also compared with commonly used splitless injection. To be included in the study measurements had to have an uncertainty lower than 0.5 per mille for dVPDB 13C and minimum peak height of 200 mV. The lower concentration limit at which these criteria were fulfilled for PAHs were 30 2ng/µl for 1 µl of splitless injection and 0.3 and 0.2ng/µl for 50 and 100 µl of large volume injection respectively.; JRC.D.4-Isotope measurements

Application of Bar Adsorptive Microextraction-Large-Volume Injection-Gas Chromatography-Mass Spectrometric Method for the Determination of Trace Levels of Agrochemicals in Real Matrices

Bernarda,João R.; Ahmad,Samir M.; Almeida,Carlos; Neng,Nuno R.; Nogueira,José Manuel F.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2015 EN
Relevância na Pesquisa
65.81%
Bar adsorptive microextraction followed by liquid desorption in combination with large volume injection gas chromatography coupled to mass spectrometry, under selected ion monitoring mode acquisition (BAµE-LD/LVI-GC-MS(SIM)), was applied for the determination of trace levels of different classes of agrochemicals (using alachlor, diniconazole, fenpropathrin, as well as cis and trans-permethrin as model compounds) in environmental water and wine matrices. Assays performed on 25 mL of ultra-pure water samples spiked at the 2.0 µg L-1 level, yielded recoveries ranging from 55.2 to 105.6%, under optimized experimental conditions. The analytical performance showed convenient detection limits (8.0 to 32.0 ng L-1) and good linear dynamic ranges (0.03 to 4.00 µg L-1), with remarkable determination coefficients (r2 > 0.9982). Excellent repeatability, based in relative standard deviation (RSD) was also achieved through intraday (RSD < 7.5%) and interday (RSD < 7.0%) assays. Studies performed on surface and ground water, as well as wine samples, using the standard addition method, revealed good sensitivity at the trace level.

Effects of volume resuscitation on splanchnic perfusion in canine model of severe sepsis induced by live Escherichia coli infusion

Lagoa, Claudio ; Figueiredo, Luiz de; Cruz, Ruy ; Silva, Eliézer ; Rocha e Silva, Maurício 
Fonte: Biblioteca Digital da Produção Intelectual da USP Publicador: Biblioteca Digital da Produção Intelectual da USP
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
35.76%
Abstract Introduction We conducted the present study to investigate whether early large-volume crystalloid infusion can restore gut mucosal blood flow and mesenteric oxygen metabolism in severe sepsis. Methods Anesthetized and mechanically ventilated male mongrel dogs were challenged with intravenous injection of live Escherichia coli (6 × 109 colony-forming units/ml per kg over 15 min). After 90 min they were randomly assigned to one of two groups – control (no fluids; n = 13) or lactated Ringer's solution (32 ml/kg per hour; n = 14) – and followed for 60 min. Cardiac index, mesenteric blood flow, mean arterial pressure, systemic and mesenteric oxygen-derived variables, blood lactate and gastric carbon dioxide tension (PCO2; by gas tonometry) were assessed throughout the study. Results E. coli infusion significantly decreased arterial pressure, cardiac index, mesenteric blood flow, and systemic and mesenteric oxygen delivery, and increased arterial and portal lactate, intramucosal PCO2, PCO2 gap (the difference between gastric mucosal and arterial PCO2), and systemic and mesenteric oxygen extraction ratio in both groups. The Ringer's solution group had significantly higher cardiac index and systemic oxygen delivery...

An example of simulation tools use for large injection moulds design: The CONTENUR™ 2400 l solid waste container

Aisa, J.; Javierre, Carlos; Serna, J. A. de la
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
Relevância na Pesquisa
35.82%
5 pages, 8 figures, 3 tables.-- Available online 5 July 2005.; Large containers with volumes above 1100 l are usually produced using procedures such as rotomoulding process. These techniques have no part weight or dimensional limits. T.I.I.P., injection moulding plastic group of the Department of Mechanical Engineering of the Zaragoza University, developed with CONTENUR™ a new product under European norms for solid waste containers up to 2000 l volume; the result was a new main body up to 60 kg weight in one part. The design process combined several CAE tools (aesthetical design, mechanical design and rheological simulation) and, in last June, showed final result and passed different tests. Nowadays, more than 5000 samples are on the streets without basic modifications in the mould (more than 100 tonnes weight). The paper focuses on the methodology used to integrate tool and process design with product definition (i.e. injection pressure and clamp force versus thickness and part shape). Some parameters about process control in this particular mould (injection rate, temperature, viscosity, gate location, …) are detailed.; The authors want to extend their gratitude to T.I.I.P.– a.i.T.I.I.P. Group and CONTENUR Technical Staff, for their support and facilities to reach this final goal.; Peer reviewed

Optimisation of stir bar sorptive extraction and liquid desorption combined with large volume injection-gas chromatography–quadrupole mass spectrometry for the determination of volatile compounds in wines

Coelho, Elisabete; Perestrelo, Rosa; Neng, Nuno R.; Câmara, José S.; Coimbra, Manuel A.; Nogueira, J. M. F.; Rocha, Sílvia M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /06/2008 ENG
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Stir bar sorptive extraction and liquid desorption followed by large volume injection coupled to gas chromatography–quadrupole mass spectrometry (SBSE–LD/LVI-GC–qMS) had been applied for the determination of volatiles in wines. The methodology was optimised in terms of extraction time and influence of ethanol in the matrix; LD conditions, and instrumental settings. The optimisation was carried out by using 10 standards representative of the main chemical families of wine, i.e. guaiazulene, E,E-farnesol, β-ionone, geranylacetone, ethyl decanoate, β-citronellol, 2-phenylethanol, linalool, hexyl acetate and hexanol. The methodology shows good linearity over the concentration range tested, with correlation coefficients higher than 0.9821, a good reproducibility was attained (8.9–17.8%), and low detection limits were achieved for nine volatile compounds (0.05–9.09 μg L−1), with the exception of 2-phenylethanol due to low recovery by SBSE. The analytical ability of the SBSE–LD/LVI-GC–qMS methodology was tested in real matrices, such as sparkling and table wines using analytical curves prepared by using the 10 standards where each one was applied to quantify the structurally related compounds. This methodology allowed, in a single run...

Application of Programmed Temperature Vaporization Large Volume Injection Gas Chromatography (PTV-LVI-GC) to the Analysis of Polycyclic Aromatic Hydrocarbons (PAHs) in Soils

Delgadillo-Marín,Miguel Ángel; Peña-Álvarez,Araceli; Villalobos,Mario
Fonte: Sociedad Química de México A.C. Publicador: Sociedad Química de México A.C.
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2013 EN
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A sensitive, selective and robust method was developed to quantify low levels of polycyclic aromatic hydrocarbons (PAHs) in soils by means of Programmed Temperature Vaporization - Large Volume Injection (PTV-LVI) coupled to gas chromatography with flame ionization detection. Optimal vent pressure and flux at the PTV inlet of the GC system were determined by comparison of peak areas obtained from injection of a standard PAHs mixture at different conditions. Assessment of method performance was carried out with home-made standards prepared by spiking three non-PAH contaminated soils that contained 1.8%, 4.6% and 25% natural organic matter (NOM), with mixtures of six different PAHs at low concentration levels. Detection limits between 9 and 12 ng g-1 and variation coefficients below 11% were determined from analysis of spiked samples of the soil with lowest NOM content. PAHs recoveries typically ranged from 61% to 96% for the three studied soils.