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Caracterização e gênese de solos e de depósito de caulim associado, São Gabriel da Cachoeira - AM; Characterization and Genesis of soils and kaolin deposits associated, São Gabriel da Cachoeira - AM

Ishida, Débora Ayumi
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 05/08/2010 PT
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Em São Gabriel da Cachoeira, estado do Amazonas, foi estudado, por meio de uma toposse-quência, um sistema Latossolo-Espodossolo com caulim associado, desenvolvido a partir de rochas granito gnáissicas do embasamento cristalino. Na topossequência, de montante para jusante, foram descritos e amostrados quatro perfis de solo: Espodossolo Humilúvico (P1) no topo, dois Latossolos Amarelos (P2 e P3) na meia encosta e Gleissolo Háplico (P4) na base. Os objetivos principais foram estudar o funcionamento desse sistema de transformação a par-tir de sua caracterização morfológica, química, física e mineralógica e obter informações so-bre as características cristalográficas das caulinitas a partir do estudo do grau de ordem estru-tural. A caracterização e gênese dos solos e do caulim foram estudadas por curva de retenção de água no solo, difração de raios-X, análise térmica diferencial e gravimétrica, espectrosco-pia por reflectância difusa, análise química total e análises microscópicas. A ordem estrutural das caulinitas foi avaliada a partir dos cálculos dos índices de Hinckley (IH), Stoch (IK), Apa-ricio-Galán-Ferrell (IAGF), Liètard (R2), Amigó (001 e 002), Hughes-Brown (IHB) e Plan-çon-Zacharie (IPZ) e das temperaturas de desidroxilação da caulinita e nucleação da mulita. Esses estudos permitiram concluir que: (i) o sistema de solos na topossequência está em fun-cionamento e levando à formação dos Espodossolos em detrimento da cobertura laterítica...

Avaliação do potencial antialérgico de flavonóides: estudo sinergístico e influência de sistemas lipossomais; Evaluation of the potential antiallergic flavonoids: synergistic influence and liposomal systems

Oliveira, Mariana Bellini
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 04/03/2013 PT
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Os problemas decorrentes de doenças alérgicas é tema em destaque atualmente devido ao aumento de pessoas que vêm apresentando sintomas e sofrendo as consequências de mudanças aceleradas nos costumes da nossa sociedade. Apesar das diversas terapias oferecidas, pacientes alérgicos ainda sofrem com efeitos colaterais decorrentes do uso de medicamentos anti-alérgicos. Assim, a busca por novas alternativas que possam amenizar os sintomas alérgicos torna-se relevante. As substâncias naturais tem sido alvo de intensa investigação devido às propriedades farmacológicas no tratamento de diversas doenças incluindo as alérgicas. Neste contexto, este trabalho foi focado no extrato Vimang e seu componente majoritário, a mangiferina (Mgf), que tem apresentado atividades biológicas diversas. Sabendo-se que a atividade biológica de um extrato pode ser potencializada pelo sinergismo entre seus componentes, foi avaliado o efeito sinérgico de substâncias isoladas do Vimang, tais como mangiferina, quercetina, catequina, ácido gálico e benzóico. Esses componentes foram combinados e as misturas avaliadas quanto à capacidade em inibir a desgranulação mastocitária. O Vimang, a quercetina e mangiferina inibem a desgranulação mastócitária enquanto catequina...

Análise químico-farmacêutica e estudo de estabilidade do voriconazol; Chemical-pharmaceutical analysis and stability study of voriconazole

Adams, Andréa Inês Horn
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
POR
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Este trabalho apresenta estudo sobre o voriconazol, antifúngico de amplo espectro liberado para tratamento de infecções fúngicas invasivas no ano de 2002, focado no controle de qualidade e estudo de estabilidade. Foram realizados testes, ainda não citados na literatura, que visaram à caracterização do fármaco tais como: espectrofotometria na região do infravermelho, espectroscopia de ressonância magnética nuclear de hidrogênio e de carbono. Os seguintes métodos de análise quantitativa do fármaco em comprimidos foram desenvolvidos e validados: espectrofotometria na região do UV, cromatografia a líquido de alta eficiência e ensaio microbiológico - método de difusão em ágar. Todos os métodos foram avaliados frente aos parâmetros de linearidade, exatidão e precisão. A especificidade foi avaliada nos métodos de CLAE e UV, pela análise de placebo (CLAE e UV) e testes de degradação forçada (CLAE). A robustez foi avaliada no método de CLAE. Os resultados obtidos através destes métodos foram comparados estatisticamente por ANOVA, que indicou não haver diferenças estatisticamente significativas entre os mesmos; no entanto, os métodos por CLAE e ensaio microbiológico possibilitam a quantificação do voriconazol em amostras degradadas. Foram estudadas as estabilidades térmica...

Avaliação da degradação fotoquímica de corante alimentício e lixiviação de corantes têxteis de fibras de algodão expostos a suor sintético por método cromatográficos

Santos, Tuane Cristina dos
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Dissertação de Mestrado Formato: 85 f. : il. -
POR
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Pós-graduação em Química - IQ; This work investigated the photochemical degradation of the dye tartrazine, widely used in food industry, using spectrophotometric methods and liquid chromatography coupled with diode array (HPLC-DAD) and mass spectrometry (LC-MS/MS) detection. Furthermore, through the Ames test, was studied the mutagenicity of the dye and it`s photodegradation by-products. The photolysis studies were conducted under UV and sunlight, with a more pronounced dye degradation achieved under artificial light in a solution of acidic pH. Total discoloration of a 1x10-5 mol L-1 tartrazine solution was obtained after 30 min of exposure to 125 W UV light, demanding an energy dose of 37.8 J cm-2. The results showed the generation of 5 by-products, derived from the opening of the five-membered ring, identified by LC-MS/MS analysis. The analysis of these data enabled the proposition of a degradation pathway for the dye tartrazine. The Ames test, using Salmonella/microsome, was conducted for the dye at a concentration of 5.34 mg / plate and for the solutions obtained after exposure to UV irradiation, showing that the dye does not possess mutagenic properties for strains TA98 and TA100 of S. typhimurium, with and without exogenous metabolization (S9). In the next step...

Soils contaminated with hexavalent chromium

Fonseca, Bruna Catarina da Silva
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Tese de Doutorado
Publicado em 21/07/2011 ENG
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Tese de doutoramento em Engenharia Química e Biológica; The interest in environmental soil science has been growing in the last years due to the continuous degradation of this major natural resource. With this in mind, and because chromium and lead are two of the most toxic heavy metals frequently detected as soil contaminants in the Portuguese territory, the study and development of few remediation techniques and the indissociable description of the sorption and migration of these two heavy metals in soils, were the main objectives of the research work described in this thesis. Primarily, a representative sample of a typical loamy sand soil was collected in Porto, Portugal, in a zone of intense agriculture activity. This soil was used for a series of tests concerning the adsorption, transport and fate of the two targeted metals, as well as the main factors affecting it like pH, contaminant concentration and competition. The adsorption equilibrium of both metals was evaluated through the fitting of eight isotherm models to each experimental data set. The best fitting was observed for the Redlich-Peterson and Khan models for the adsorption of chromium and of lead, respectively. On its turn, the sorption kinetics was evaluated using three models - Elovich...

In vitro dissolution of curium oxide using a phagolysosomal simulant solvent system.

Helfinstine, S Y; Guilmette, R A; Schlapper, G A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1992 EN
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Detailed study of actinide oxide behavior in alveolar macrophages (AM) in vitro is limited because of the short life span of these cells in culture. We created an in vitro dissolution system that could mimic the acidic phagolysosomal environment for the actinide and be maintained for an indefinite period so that dissolution of more insoluble materials could be measured. The dissolution system for this investigation, consisting of nine different solutions of HCl and the chelating agent diethylenetriamine pentaacetate (DTPA) in distilled water, is called the phagolysosomal simulant solvent (PSS). In this system, both the pH and the amount of DTPA were varied. We could observe the effect of altering pH within a range of 4.0-6.0 (similar to that of the phagolysosome) and the effect of the molar ratio of DTPA to curium at 1000:1, 100:1, or 10:1. We chose curium sequioxide (244Cm2O3) to validate the PSS for actinide dissolution versus that occurring in AM in vitro because it dissolves significantly in less than 1 week. The polydisperse 244Cm2O3) aerosol was generated, collected on filters, resuspended, and added to the PSS solutions and to cultured canine AM. By comparing dissolution in the two systems directly, we hoped to arrive at an optimum PSS for future dissolution studies. PSS and cell culture samples were taken daily for 7 days after exposure and tested for the solubilized curium. The amount of soluble material was determined by ultracentrifugation to separate the insoluble Cm2O3 from the soluble curium in the PSS solutions and filtration for the cell-containing material.(ABSTRACT TRUNCATED AT 250 WORDS)

Amperometric Nitric Oxide Sensors with Enhanced Selectivity Over Carbon Monoxide via Platinum Oxide Formation Under Alkaline Conditions

Jensen, Gary C.; Zheng, Zheng; Meyerhoff, Mark E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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An improved planar amperometric nitric oxide (NO) sensor with enhanced selectivity over carbon monoxide (CO), a volatile interfering species for NO sensors that has been largely overlooked until recently, is described. Formation of an oxide film on the inner platinum working electrode via anodic polarization using an inner alkaline electrolyte solution provides the basis for improved selectivity. Cyclic voltammetry reveals that formation of oxidized Pt film inhibits adsorption of CO to the electrode surface, which is a necessary initial step in the electrocatalytic oxidation of CO on Pt. Previous NO gas sensors that employ internal electrolyte solutions have been assembled using acidic internal solutions, that inhibit the formation of a dense platinum oxide film on the working electrode surface. It is demonstrated herein that increasing the internal electrolyte pH promotes oxidized platinum film formation, resulting in improved selectivity over CO. Selectivity coefficients (log KNO,j) for sensors assembled with internal solutions at various pH values range from −0.08 at pH 2.0 to −2.06 at pH 11.7 with average NO sensitivities of 1.24 nA/μM and LOD of <1 nM.

Mussel inspired protein-mediated surface functionalization of electrospun nanofibers for pH-responsive drug delivery

Jiang, Jiang; Xie, Jingwei; Ma, Bing; Bartlett, David E.; Xu, An; Wang, Chi-Hwa
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
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pH-responsive drug delivery systems could mediate drug releasing rate by changing pH values at specific time as per the pathophysiological need of the disease. Herein, we demonstrated a mussel inspired protein polydopamine coating can tune the loading and releasing rate of charged molecules from electrospun poly (ε-caprolactone) (PCL) nanofibers in solutions with different pH values. In vitro release profiles showed that the positive charged molecules released significantly faster in acidic than those in neutral and basic environments within the same incubation time. The results of fluorescein diacetate staining and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays showed the viability of cancer cells after treatment with doxorubicin released media at different pH values qualitatively and quantitatively, indicating the media contained doxorubicin which was released in solutions at low pH values could kill significantly higher number of cells than that released in solutions at high pH values. Together, the pH-responsive drug delivery systems based on polydopamine-coated PCL nanofibers could have potential applications in oral delivery of anticancer drugs for treating gastric cancer and vaginal delivery of anti-viral drugs or anti-inflammatory drugs...

Nanofiltration of Mine Water: Impact of Feed pH and Membrane Charge on Resource Recovery and Water Discharge

Mullett, Mark; Fornarelli, Roberta; Ralph, David
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 27/03/2014 EN
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Two nanofiltration membranes, a Dow NF 270 polyamide thin film and a TriSep TS 80 polyamide thin film, were investigated for their retention of ionic species when filtering mine influenced water streams at a range of acidic pH values. The functional iso-electric point of the membranes, characterized by changes in retention over a small pH range, were examined by filtering solutions of sodium sulphate. Both membranes showed changes in retention at pH 3, suggesting a zero net charge on the membranes at this pH. Copper mine drainage and synthetic solutions of mine influenced water were filtered using the same membranes. These solutions were characterized by pH values within 2 and 5, thus crossing the iso-electric point of both membranes. Retention of cations was maximized when the feed solution pH was less than the iso-electric point of the membrane. In these conditions, the membrane has a net positive charge, reducing the transmission rate of cations. From the recoveries of a range of cations, the suitability of nanofiltration was discussed relative to the compliance with mine water discharge criteria and the recovery of valuable commodity metals. The nanofiltration process was demonstrated to offer advantages in metal recovery from mine waste streams...

Evaluation of Hemagglutination Activity of Chitosan Nanoparticles Using Human Erythrocytes

de Lima, Jefferson Muniz; Sarmento, Ronaldo Rodrigues; de Souza, Joelma Rodrigues; Brayner, Fábio André; Feitosa, Ana Paula Sampaio; Padilha, Rafael; Alves, Luiz Carlos; Porto, Isaque Jerônimo; Batista, Roberta Ferreti Bonan Dantas; de Oliveira, Julian
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
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Chitosan is a polysaccharide composed of randomly distributed chains of β-(1-4) D-glucosamine and N-acetyl-D-glucosamine. This compound is obtained by partial or total deacetylation of chitin in acidic solution. The chitosan-based hemostatic agents have been gaining much attention in the management of bleeding. The aim of this study was to evaluate in vitro hemagglutination activity of chitosan nanoparticles using human erythrocytes. The preparation of nanoparticles was achieved by ionotropic gelification technique followed by neutralization with NaOH 1 mol/L−1. The hemagglutination activity was performed on a solution of 2% erythrocytes (pH 7.4 on PBS) collected from five healthy volunteers. The hemolysis determination was made by spectrophotometric analysis. Chitosan nanoparticle solutions without NaOH addition changed the reddish colour of the wells into brown, suggesting an oxidative reaction of hemoglobin and possible cell lysis. All neutralized solutions of chitosan nanoparticles presented positive haemagglutination, without any change in reaction color. Chitosan nanoparticles presented hemolytic activity ranging from 186.20 to 223.12%, while neutralized solutions ranged from 2.56 to 72.54%, comparing to distilled water. Results highlight the need for development of new routes of synthesis of chitosan nanoparticles within human physiologic pH.

The Semen pH Affects Sperm Motility and Capacitation

Zhou, Ji; Chen, Li; Li, Jie; Li, Hongjun; Hong, Zhiwei; Xie, Min; Chen, Shengrong; Yao, Bing
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 14/07/2015 EN
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As the chemical environment of semen can have a profound effect on sperm quality, we examined the effect of pH on the motility, viability and capacitation of human sperm. The sperm in this study was collected from healthy males to avoid interference from other factors. The spermatozoa cultured in sperm nutrition solution at pH 5.2, 6.2, 7.2 and 8.2 were analyzed for sperm total motility, progressive motility (PR), hypo-osmotic swelling (HOS) rate, and sperm penetration. Our results showed that these parameters were similar in pH 7.2 and 8.2 sperm nutrition solutions, but decreased in pH 5.2 and 6.2 solutions. The HOS rate exhibited positive correlation with the sperm total motility and PR. In addition, the sperm Na+/K+-ATPase activity at different pHs was measured, and the enzyme activity was significantly lower in pH 5.2 and 6.2 media, comparing with that in pH 8.2 and pH 7.2 solutions. Using flow cytometry (FCM) and laser confocal scanning microscopy (LCSM) analysis, the intracellular Ca2+ concentrations of sperm cultured in sperm capacitation solution at pH 5.2, 6.2, 7.2 and 8.2 were determined. Compared with that at pH 7.2, the mean fluorescence intensity of sperm in pH 5.2 and 6.2 media decreased significantly, while that of pH 8.2 group showed no difference. Our results suggested that the declined Na+/K+-ATPase activity at acidic pHs result in decreased sperm movement and capacitation...

Immunhistochemische Untersuchungen über die Pathogenese der verkapselnden Peritonealsklerose (EPS) bei Peritonealdialyse-Patienten; Immunohistochemical findings concerning the pathogenesis of encapsulating peritoneal fibrosis (EPS) in peritoneal dialysis patients

Reimold, Fabian Raoul
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
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Immunhistochemische Untersuchungen über die Pathogenese der verkapselnden Peritonealsklerose (EPS) bei Peritonealdialyse-Patienten Hintergrund Die verkapselnde Peritonealsklerose (EPS) stellt eine schwerwiegende und teilweise lebensbedrohliche Erkrankung bei Peritonealdialyse-Patienten dar, die in vielen Fällen zum Abbruch der Peritonealdialyse führt. Die Pathogenese der EPS ist nicht endgültig geklärt. Es gibt mehrere Ansätze, die über den Einfluss von Dialysaten, einer sukzessiven Entzündung und einer Hochregulierung von Transkriptionsfaktoren, wie NF-kappa B versuchen, die Ätiologie zu erklären. In dieser Arbeit haben wir den Einfluss verschiedener Transkriptionsfaktoren und anderer Proteine auf die Entwicklung der EPS untersucht. Methoden Es wurden histologische Proben von Peritonealdialyse-Patienten mit EPS [n=9] verwendet. Diese wurden mit verschiedenen histologischen und immunhistologischen Färbungen behandelt. Neben einer Hämatoxylin-Eosin-Färbung (HE) wurden Antikörper gegen NF-kappa B, TGF-beta 1, TGF-beta 2, TGF-beta-Rezeptor I, TGF-beta-Rezeptor II, FGF-BP, CTGF und VEGF angewandt. Die Arbeit umfasste weiterhin vier verschiedene Kontrollgruppen: eine Gruppe mit Peritonealdialyse-Patienten (CAPD) ohne EPS [n=10]...

EFFECT OF TAILINGS MINERALOGY AND INFILTRATION WATER CHEMISTRY ON ARSENIC RELEASE FROM HISTORIC GOLD MINE TAILINGS

KAVALENCH, Jennifer
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
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The existence of small-scale gold mining in Nova Scotia between 1868 and 1942 has resulted in many high arsenic (As) tailings areas in the province, some of which are near rural/urban areas and are used for recreational activities such as dirt bike racing and all-terrain vehicle (ATV) riding. Because of the natural association of As with gold ore in the Meguma Terrane, processing of ore has resulted in As-rich mine waste that contains up to 2500 times more As than the Canadian soil quality guideline of 12 mg/kg. These high As concentrations in combination with the recreational use of these sites creates a risk of human exposure. The objective of this work was to investigate the effects of different cover options that might be used to mitigate the risk of human exposure. Four tailings samples were selected to represent the geochemical variability from two tailings areas: Montague gold mines and Goldenville. These samples were characterized and subjected to 29 weeks of column testing, in which each sample was leached with three different input solutions including synthetic rainwater (to simulate uncovered tailings exposed to natural acid rain), synthetic rainwater equilibrated with calcium carbonate (to simulate rainwater percolation through a crushed limestone cover)...

Extracção líquido-líquido de iões metálicos de soluções aquosas cloretadas por derivados de ditiomalonamida N,N'-tetrassubstituídos

Ortet, Osvaldo Arlindo Lopes
Fonte: Universidade de Lisboa Publicador: Universidade de Lisboa
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em //2009 POR
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Tese de mestrado em Química (Química Aplicada ao Património Cultural), apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2009; Este trabalho subdividiu-se em duas partes, primeiramente incidiu-se na síntese e caracterização de dois derivados de malonamida N,N'-tetrassubstituídas, a N,N'-dimetil-N,N'-difenilmalonamida (DMDPHMA) e a N,N'-dimetil-N,N'-diciclohexilmalonamida (DMDCHMA), seguida da conversão desses derivados em ditiomalonamidas, obtendo-se a N,N'-dimetil-N,N'-difenilditiomalonamida (DMDPHDTMA) e a N,N'-dimetil-N,N'-diciclohexilditiomalonamida (DMDCHDTMA), respectivamente, sendo que o método eficaz para a referida conversão foi através do uso do reagente de Lawesson. Todos os compostos sintetizados foram analisados e caracterizados por técnicas espectroscópicas, tais como infravermelho com transformada de Fourier (FTIR) e ressonância magnética nuclear (RMN) de 1H e de 13C. Determinaram-se também os respectivos pontos de fusão. Os derivados de ditiomalonamida foram também analisados pela técnica de espectrometria de massa com ionização por electrospray (ESI-MS). A segunda parte do trabalho baseou-se na investigação das capacidades extractivas dos derivados de ditiomalonamida para a recuperação de iões metálicos seleccionados (Ag(I)...

Sodium-dependent control of intracellular pH in Purkinje fibres of sheep heart.

Ellis, D; MacLeod, K T
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/1985 EN
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Intracellular pH (pHi) of Purkinje fibres from sheep heart was recorded with pH-sensitive glass micro-electrodes. The cells were acidified by one of three methods: (1) exposure to and subsequent removal of NH4Cl, (2) exposure to solutions containing 5% CO2 or (3) exposure to an acidic Tyrode solution. The pHi recovery from these acidifications was studied. The time constant of recovery from an acidification induced by NH4Cl was almost twice as long as that from one induced by CO2 or acid extracellular pH. Following an acidification induced by exposure to CO2 the time constant of pHi recovery was not changed when the cell was depolarized to -40 mV (by replacement of some Na+ by K+). An intracellular acidification was produced when extracellular Na+ was removed and replaced by quaternary ammonium ions or K+. Such Na+-free solutions also inhibited pHi recovery from an acidification. A 50% inhibition of the rate of recovery was produced by lowering the [Na+]o to 8 mM. When used as a Na+ substitute, Li+ could permit recovery. Tris (22 mM) changed pHi in the alkaline direction. Amiloride (1 mM) or a decrease in temperature slowed the recovery from an acidification (Q10 = 2.65). There was no effect of SITS (4-acetamido-4'-isothiocyanatostilbene-2...

Comparison of three inhaled non-steroidal anti-inflammatory drugs on the airway response to sodium metabisulphite and adenosine 5'-monophosphate challenge in asthma.

Wang, M.; Wisniewski, A.; Pavord, I.; Knox, A.; Tattersfield, A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1996 EN
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BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) are used to assess the role of prostaglandins in asthma but their effects on bronchoconstrictor challenges have been inconsistent. The effects of three nebulised nonsteroidal anti-inflammatory drugs on the airway response to inhaled sodium metabisulphite (MBS) and adenosine 5'-monophosphate (AMP) were compared in the same asthmatic subjects to see whether contractile prostaglandins were involved in MBS or AMP induced bronchoconstriction. A possible protective effect of the osmolarity or pH of the inhaled solutions was also assessed. METHODS: Two double blind placebo controlled studies were carried out. In study 1, 15 non-aspirin sensitive patients with mild asthma attended on four occasions and inhaled 5 ml of lysine aspirin (L-aspirin) 900 mg, indomethacin 50 mg, sodium salicylate 800 mg, or saline 20 minutes before an inhaled MBS challenge. On four further occasions 14 of the patients inhaled the same solutions followed by an inhaled AMP challenge. In study 2, 10 of the patients attended on four additional occasions and inhaled 5 ml of 0.9%, 3%, 10%, or 9.5% saline with indomethacin 50 mg 20 minutes before an inhaled MBS challenge. RESULTS: In study 1 inhaled lysine aspirin had a similar effect on MBS and AMP induced bronchoconstriction...

Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

Erdemir,Ugur; Yildiz,Esra; Eren,Meltem Mert; Ozel,Sevda
Fonte: Faculdade De Odontologia De Bauru - USP Publicador: Faculdade De Odontologia De Bauru - USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2013 EN
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Objectives: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. Material and Methods: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group). For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05). Results: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (p<0.001) in different solutions (p<0.001). The effect of different solutions on the surface hardness values of the restorative materials was tested using Bonferroni's multiple comparison tests...

Remoción de iones sulfato y metales pesados desde soluciones acuosas que simulan aguas de mina usando mezcla de cal, silicatos nano-estructurados y policloruro de aluminio en una celda DAF

Verdugo Gallegos, Luis Alberto
Fonte: Universidad de Chile Publicador: Universidad de Chile
Tipo: Tesis
ES
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Memoria para optar al Título de Químico; En esta Memoria de Título se estudió la remoción del anión sulfato en presencia de Cu(II) y Zn(II) desde soluciones acuosas que simulan un agua ácida residual de mina, empleando mezclas de cal, policloruro de aluminio y silicatos de calcio nanoestructurados. Los experimentos se realizaron en una celda de flotación de aire disuelto (DAF).Se logró una buena remoción de sulfato, utilizando diferentes dosificaciones de cal y PAC, alcanzándose concentraciones finales de este anión en las soluciones refinos, muy por debajo de la norma ambiental vigente y en un tiempo relativamente corto. El mecanismo de remoción de este anión está basado en la formación de etringita. Los resultados confirmaron también que la adición de sólo cal no remueve ion sulfato en un grado suficiente. Se preparó un silicato de calcio nano-estructurados mediante la reacción de una solución de silicato de sodio y Ca(OH)2, manteniendo una intensa agitación durante el proceso. Análisis indican que el sólido obtenido es de estructura más bien amorfa, con nano-capas de placas tetraédricas de silicatos de calcio de espesor variable entre 10-20 nm y diámetros entre 80 y 100 nm, presentando una superficie BET variable entre 200 y 300 m2/g. Los resultados experimentales indican que los silicatos de calcio nano-estructurados por si solos...

Estudio de la extracción de Cu(II) y Zn(II) desde soluciones acuosas ácidas mediante el empleo de membranas líquidas emulsificadas, microencapsulación de extractantes y silicatos de calcio nanoestructurados

Fonseca París, Carla Karín
Fonte: Universidad de Chile; CyberDocs Publicador: Universidad de Chile; CyberDocs
Tipo: Tesis
ES
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Doctor en Química; Se estudió la extracción de cobre (II) y cinc (II) desde soluciones acuosas que simulan drenajes ácidos de mina y residuos industriales líquidos mediante el empleo de tres metodologías: Membranas Líquidas Emulsificadas, Microencapsulación de Extractantes y Silicatos de Calcio Nanoestructurados. La separación de iones cinc desde una solución de drenajes ácidos de mina se estudió mediante la metodología de membranas líquidas emulsificadas preparadas con el extractante ácido 2-etilhexil fosfórico y el surfactante monooleato de sorbitan. Se observó un importante transporte de los iones cinc desde la solución de alimentación hacia la fase acuosa interna. La extracción de cinc fue afectada por el pH y la concentración de la fase acuosa de alimentación, la concentración del extractante y la concentración de la solución de retroextracción. Los resultados experimentales obtenidos se modelaron utilizando un mecanismo basado en un proceso mediante transporte facilitado y un modelo de reacción interfacial heterogénea, el cual considera la reacción química con el extractante en la interfase externa. El modelo explica consistentemente los resultados experimentales. La extracción de cinc y cobre se estudió mediante la microencapsulación de moléculas extractantes en una matriz polimérica de estireno y 1...

A Combined Small-Angle X-ray and Neutron Scattering Study of the Structure of Purified Soluble Gastrointestinal Mucins

Georgiades, Pantelis; di Cola, Emanuela; Heenan, Richard K; Pudney, Paul D A; Thornton, David J; Waigh, Thomas A
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
EN
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The structures of purified soluble porcine gastric (Muc5ac) and duodenal (Muc2) mucin solutions at neutral and acidic pH were examined using small-angle X-ray scattering and small-angle neutron scattering experiments. We provide evidence for the morphology of the network above the semidilute overlap concentration and above the entanglement concentration. Furthermore, we investigated the gelation of both types of mucin solutions in response to a reduction in pH, where we observed the formation of large-scale heterogeneities within the polymer solutions, typical of microphase-separated gels. The concentration dependence of the inhomogeneity length scale (Ξ) and the amplitude of the excess scattering intensity [Iex(0)] are consistent with previously studied gelled synthetic polymeric systems. The persistence lengths of the chains were found to be similar for both Muc5ac and Muc2 from Kratky plots of the neutron data (8 ± 2 nm). © 2014 Wiley Periodicals, Inc. Biopolymers 101: 1154–1164, 2014.