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Carvalho, Paulo Roberto Nogueira
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Id: biblio-982805
Autor: Silva, Marta Gomes da; Garcia, Adão Luiz; Carvalho, Paulo Roberto Nogueira.
Título: The annatto carotenoids and the norbixin absorption coefficient / Carotenoides de urucum e o coeficiente de absorção da norbixina
Fonte: Rev. Inst. Adolfo Lutz;(77):1-8, 2018. ilus, tab.
Idioma: en.
Resumo: Annatto seeds present cis-bixin as the major carotenoids, but the norbixin salt is the mainpigment present in dyes obtained from the alkaline extraction process. For analyzing the norbixin,the absorptions are obtained in the two spectral peaks with higher intensity, but discrepanciesin the published extinction values have led to serious doubts. Taking into account the use ofabsorption coefficient for evaluating the norbixin concentration in annatto seeds and extracts, thepresent study evaluated the absorption coefficient in various solvents and the total uncertaintyassociated with this value was determined. The norbixin standard was prepared from annattoseeds, purified by column chromatography and the purity of norbixin was evaluated by HPLC-DAD.The absorption coefficients were determined for norbixin in different solvents and the uncertaintywas evaluated. The 0.5% potassium hydroxide, the main solvent used for marketing the annattoseeds and extracts, showed the absorption coefficients of 2887 at 454nm and of 2546 at 483nm,and the estimation of expanded uncertainty (K=2) was ±86 and 85 g 100 mL-1, respectively.

O principal carotenoide em sementes de urucum é a cis-bixina, mas o sal de norbixina torna-seo principal pigmento presente em corantes obtidos pelo processo de extração alcalino.Para a análise de norbixina as absorbâncias são obtidas nos dois picos espectrais de maiorintensidade, mas discrepâncias no valor de absortividade levam a sérias dúvidas. Levando-se emconta o uso do coeficiente de absorção na avaliação da concentração de norbixina em sementesde urucum e extratos, este trabalho teve como objetivo avaliar o coeficiente de absorção emvários solventes e determinar a incerteza expandida associada a esse valor. Para a execução doestudo, um padrão de norbixina foi preparado a partir de sementes de urucum, purificado emcoluna aberta e a pureza da norbixina foi avaliada por HPLC-DAD. O coeficiente de absorçãoda norbixina foi determinado pela construção de curvas analíticas em diferentes solventes e aincerteza expandida foi avaliada. O hidróxido de potássio a 0,5%, principal solvente utilizadona comercialização de sementes de urucum e extratos, apresentou o coeficiente de absorçãodeterminado em 2887 a 454nm e 2546 a 483nm e a estimação da incerteza expandida (K=2) foi86 e 85 g 100 mL-1, respectivamente.
Descritores: Corantes
Pigmentos da Retina
Solventes
Limites: Humanos
Responsável: BR91.2 - Centro de Documentação


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Id: lil-788974
Autor: Gururaj, P; Ramalingam, Subramanian; Devi, Ganesan Nandhini; Gautam, Pennathur.
Título: Process optimization for production and purification of a thermostable, organic solvent tolerant lipase from Acinetobacter sp. AU07
Fonte: Braz. j. microbiol;47(3):647-657, July-Sept. 2016. tab, graf.
Idioma: en.
Projeto: Department of Biotechnology, Government of India.
Resumo: ABSTRACT The purpose of this study was to isolate, purify and optimize the production conditions of an organic solvent tolerant and thermostable lipase from Acinetobacter sp. AU07 isolated from distillery waste. The lipase production was optimized by response surface methodology, and a maximum production of 14.5 U/mL was observed at 30 ºC and pH 7, using a 0.5% (v/v) inoculum, 2% (v/v) castor oil (inducer), and agitation 150 rpm. The optimized conditions from the shake flask experiments were validated in a 3 L lab scale bioreactor, and the lipase production increased to 48 U/mL. The enzyme was purified by ammonium sulfate precipitation and ion exchange chromatography and the overall yield was 36%. SDS-PAGE indicated a molecular weight of 45 kDa for the purified protein, and Matrix assisted laser desorption/ionization time of flight analysis of the purified lipase showed sequence similarity with GDSL family of lipases. The optimum temperature and pH for activity of the enzyme was found to be 50 ºC and 8.0, respectively. The lipase was completely inhibited by phenylmethylsulfonyl fluoride but minimal inhibition was observed when incubated with ethylenediaminetetraacetic acid and dithiothreitol. The enzyme was stable in the presence of non-polar hydrophobic solvents. Detergents like SDS inhibited enzyme activity; however, there was minimal loss of enzyme activity when incubated with hydrogen peroxide, Tween 80 and Triton X-100. The kinetic constants (Km and Vmax) revealed that the hydrolytic activity of the lipase was specific to moderate chain fatty acid esters. The Vmax, Km and Vmax/Km ratio of the enzyme were 16.98 U/mg, 0.51 mM, and 33.29, respectively when 4-nitrophenyl palmitate was used as a substrate.
Descritores: Compostos Orgânicos
Solventes
Proteínas de Bactérias/isolamento & purificação
Proteínas de Bactérias/biossíntese
Acinetobacter/enzimologia
Lipase/isolamento & purificação
Lipase/biossíntese
-Compostos Orgânicos/química
Solventes/química
Especificidade por Substrato
Temperatura
Proteínas de Bactérias/química
Estabilidade Enzimática
Cinética
Cromatografia por Troca Iônica
Ativação Enzimática
Espaço Extracelular/enzimologia
Concentração de Íons de Hidrogênio
Íons
Lipase/química
Lipólise
Metais
Peso Molecular
Responsável: BR1.1 - BIREME


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Id: biblio-838250
Autor: Bahceci Erdem, Semiha; Nacaroglu, Hikmet T; Isgüder, Rana; Unsal Karkiner, Canan S; Alper, Hüdaver; Can, Demet.
Título: Complicaciones pulmonares de la neumonía química: A propósito de un caso / Pulmonary complications of chemical pneumonía; a case report
Fonte: Arch. argent. pediatr;114(4):e245-e248, ago. 2016. ilus.
Idioma: en; es.
Resumo: La aspiración de hidrocarburos puede causar un daño significativo a los pulmones al inducir una respuesta inflamatoria, alveolitis exudativa hemorrágica y pérdida de la función del tensioactivo pulmonar. El efecto secundario más grave de la aspiración de hidrocarburos es la neumonía por aspiración. Anteriormente se han notificado casos de neumotórax, neumatocele, síndrome de dificultad respiratoria aguda (SDRA), absceso pulmonar, fístula broncopleural, derrame pleural bilateral hemorrágico y pioneumotórax. En este artículo presentamos el caso de un paciente hospitalizado debido a neumonía por aspiración que desarrolló pleuritis y neumotórax después de ingerir disolvente para pintura. Se presenta este caso ya que raramente se ha informado en niños como causa de complicaciones pulmonares diferentes. Es necesario evaluar integralmente a los pacientes con complicaciones asociadas a la intoxicación por hidrocarburos. Debe evitarse el alta hospitalaria temprana de los pacientes, quienes deben ser controlados durante, al menos, 48 horas, aunque no tengan síntomas respiratorios. Debe considerarse que los pacientes con neumonía química pueden tener complicaciones pulmonares graves.

Hydrocarbon aspiration (HA) can cause significant lung disease by inducing an inflammatory response, hemorrhagic exudative alveolitis, and loss of surfactant function. The most serious side effect of HA is aspiration pneumonia. Pneumothorax, pneumatocele, acute respiratory distress syndrome (ARDS), pulmonary abscess, bronchopleural fistula, bilateral hemorrhagic pleural effusion and pyopneumothorax were previously reported. Hereby we report a patient hospitalized due to aspiration pneumonia who developed pleurisy and pneumothorax after drinking paint thinner. It is presented as it was seldom reported in children to cause distinct pulmonary complications. Patients with complaints associated withhydrocarbon poisoning must be fully evaluated. They must not be discharged from the hospital early and must be followed for at least 48 hours even if they don't have respiratory symptoms. It should be kept in mind that severe pulmonary complications can develop in patients with chemical pneumonia.
Descritores: Pleurisia/induzido quimicamente
Pneumonia/induzido quimicamente
Pneumotórax/induzido quimicamente
Solventes/envenenamento
Hidrocarbonetos/envenenamento
-Pleurisia/complicações
Pneumonia/complicações
Pneumotórax/complicações
Índice de Gravidade de Doença
Limites: Humanos
Masculino
Criança
Tipo de Publ: Relatos de Casos
Responsável: AR94.1 - Centro de Información Pediatrica


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Id: biblio-967000
Autor: Zhou, Yuanyuan; Li, Song; Wang, Dalu; Zhao, Yaguang; Lei, Xiaolin.
Título: Estimation of type i collagen structure dissolved in inorganical acids from circular dichroism spectra / Estimativa da estrutura de colágeno tipo i dissolvida em ácidos inorgânicos a partir de espectros de dicroísmo circular
Fonte: Biosci. j. (Online);34(3):778-789, mai/jun. 2018. graf.
Idioma: en.
Resumo: Usually, weak inorganic acids have been used to disperse collagen as green solvents for fabricating kinds of biomaterials all the time. However, it is an open question how much the dissolving process preserves or alters the native structure of collagen till now. Herein, we have examined the effect of three different solvents (HAc, HCl, H3PO4) on the secondary structures of collagen, based on circular dichroism (CD) spectra of collagen from 185 to 260 nm together with CDNN programs. We have found that collagen almost completely preserved its triple helical structure in the three inorganic acids at pH=3.0 or so, which demonstrated that it was the concentration of free H+ in the above three solutions whose pH was fixed at 3.0 that can maintain an proper amount of surface charge on the collagen colloidal particles and appropriately loose the three-helix structure, which can not only lead to a better dispersion behavior, but also maximize the preservation of the integrity of the collagen structure. Although the fractions of kinds of secondary structures in collagen were different from all the three solvents based on CDNN data, which gave very similar results for each other. These results was tested for the first time in this work to estimate the secondary structures for collagen in the different common inorganic acids, which provides a new avenue for green collagen solvents to prepare collagen-based composite with well triple-helical structure for tissue engineering.

Habitualmente, os ácidos inorgânicos fracos têm sido usados para dispersar colágeno como solventes verdes para fabricar tipos de biomateriais o tempo todo. No entanto, é uma questão aberta quanto o processo de dissolução preserva ou altera a estrutura nativa do colágeno até agora. Aqui, examinamos o efeito de três solventes diferentes (HAc, HCl, H3PO4) nas estruturas secundárias de colágeno, com base em espectros de dicroísmo circular (CD) de colágeno de 185 a 260 nm em conjunto com programas CDNN. Descobrimos que o colágeno preservou quase completamente sua estrutura helicoidal tripla nos três ácidos inorgânicos a pH = 3,0 ou mais, o que demonstrou que foi a concentração de H+ livre nas três soluções acima cujo pH foi fixado em 3,0 que pode manter uma boa quantidade de carga superficial sobre as partículas coloidais de colágeno e destrói adequadamente a estrutura de três hélices, o que não só pode levar a um melhor comportamento de dispersão, mas também maximizar a preservação da integridade da estrutura de colágeno. Embora as frações de tipos de estruturas secundárias em colágeno fossem diferentes de todos os três solventes com base em dados CDNN, que deram resultados muito semelhantes entre si. Estes resultados foram testados pela primeira vez neste trabalho para estimar as estruturas secundárias para o colágeno nos diferentes ácidos inorgânicos comuns, o que fornece uma nova alternativa para solventes de colágeno verdes para preparar compósitos à base de colágeno com a estrutura helicoidal tripla para engenharia de tecidos.
Descritores: Dicroísmo Circular
Colágeno Tipo I
Ácidos Inorgânicos
-Solventes
Materiais Biocompatíveis
Responsável: BR396.1 - Biblioteca Central


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Id: biblio-967325
Autor: Namvar, Khashaiar; Salehi, Esmaeil Ataye; Mokhtarian, Naeim.
Título: Total phenolic compounds and antioxidant activity of Stachys turcomanica / Compostos fenólicos totais e atividade antioxidante da Stachys turcomanica
Fonte: Biosci. j. (Online);34(5):1349-1356, sept./oct. 2018.
Idioma: en.
Resumo: The subject of free radicals and their effects on biological systems is an important problem in Medicine. Antioxidants can protect biological systems against free radicals. In this study, the effect of methanol ratio (0, 20, 50, 80, and 100%) in water on extraction yield of Total phenolic (TP) compounds and antioxidant activity (AA) of Stachys turcomanica extract were evaluated. The amount of TP compounds were determined using Folin-Ciocalteu reagent, and AA measured by 2, 2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and betacaroten linoleic acid methods. The results showed extraction of phenolic compounds and their AA were affected by solvent combinations. In addition, there was a good correlation between TP content and AA of Stachys turcomanica extracts. Finally the methanol: water (80:20) was good solvent in extracting of phenolic compounds with highest AA.

O tema dos radicais livres e seus efeitos nos sistemas biológicos é um problema importante na medicina. Os antioxidantes podem proteger os sistemas biológicos contra os radicais livres. Neste estudo, avaliou-se o efeito da proporção de metanol (0, 20, 50, 80 e 100%) na água com o rendimento de extração de compostos fenólicos totais (TP) e atividade antioxidante (AA) do extrato Stachys turcomanica. A quantidade de compostos de TP foi determinada utilizando o reagente de Folin-Ciocalteu, e AA medido por 2, 2-difenil-1-picrilidrazilo (DPPH), poder antioxidante redutor férrico (FRAP) e ácido beta-caroten ácido linoleico. Os resultados mostraram a extração de compostos fenólicos e os seus AA foram afetados por combinações de solventes. Além disso, houve uma boa correlação entre o conteúdo de TP e os extratos de AA de Stachys turcomanica. Finalmente, o metanol: água (80:20) foi bom solvente na extração de compostos fenólicos com AA mais alto.
Descritores: Stachys
Biologia de Sistemas
Compostos Fenólicos
Radicais Livres
Antioxidantes
-Solventes
Metanol
Responsável: BR396.1 - Biblioteca Central


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Id: biblio-997924
Autor: Chaharom, Mohammad Esmaeel Ebrahimi; Bahari, Mahmoud; Rahbar, Mahdi; Golbaz, Sepideh.
Título: Effect of Galardin and its Solvents on the Microtensile Bond Strength of Different Adhesive Systems to Dentin
Fonte: Pesqui. bras. odontopediatria clín. integr;19(1):4438, 01 Fevereiro 2019. tab, graf.
Idioma: en.
Resumo: Objective: To evaluate the effect of a synthetic inhibitor of MMPs (Galardin) and its solvents [ethanol and dimethyl sulfoxide (DMSO)] on the microtensile bond strength (µTBS) of adhesive systems to dentin. Material and Methods: Sound human third molars (n=180) were randomly assigned into 5 based on solution type: DMSO; ethanol; Galardin + DMSO; Galardin + ethanol; and distilled water as control. Then were further subdivided into 6 based on the adhesive system, i.e. 3-step and 2-step etch-and-rinse (ER), one-step and 2-step self-etch (SE) and universal in ER and SE strategies. The samples underwent a 500-round thermocycling procedure at 5±5/55±5°C and were sectioned into 1-mm2 pieces perpendicularly in a cutting machine. The µTBS was measured at a strain rate of 1 mm/min. Data were analyzed with two-way ANOVA and post hoc Games-Howell tests (p<0.05). Results: The adhesive system and the solution had significant effects on the µTBS (p<0.001). The universal adhesive in the SE mode resulted in a significant decrease in µTBS compared to the other adhesives (p<0.05). Ethanol, too, resulted in a significant decrease in µTBS compared to other solutions (p<0.05). Conclusion: Galardin and its solvents, except for ethanol, had no detrimental effects on the immediate µTBS.
Descritores: Inibidores de Proteases
Solventes/análise
Resistência à Tração
Materiais Dentários
Dente Serotino
-Técnicas In Vitro/métodos
Dimetil Sulfóxido/efeitos adversos
Análise de Variância
Cimentos Dentários
Irã (Geográfico)
Limites: Humanos
Tipo de Publ: Estudo de Avaliação
Responsável: BR1264.1 - Biblioteca Setorial Prof Alberto M Campos


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Id: biblio-951872
Autor: Savjani, Jignasa Ketan; Pathak, Chirag.
Título: Improvement of physicochemical parameters of acyclovir using cocrystallization approach
Fonte: Braz. j. pharm. sci;52(4):727-734, Oct.-Dec. 2016. tab, graf.
Idioma: en.
Resumo: ABSTRACT Acyclovir is an antiviral drug having potent activity against the virus of herpes family and varicella zoster. Unfortunately, drug suffers very poor oral bioavailability (15-30%). The main objective of present study was to develop acyclovir cocrystals with improved solubility which may result in improvement of bioavailability. Hansen solubility approach was used as a tool to predict the cocrystal formation of a drug with selected coformer. Cocrystals of acyclovir with various coformers were screened in order to enhance their water solubility. Cocrystals of the drug were prepared using various methods like solvent evaporation, wet grinding, and antisolvent addition. Formation of cocrystals by solvent evaporation method was found to be better method amongst all. Optimization of cocrystal formation was carried out by employing different solvents as well as the stoichiometric ratio of acyclovir with that of coformer. Synthesis of cocrystals was optimized using water as a solvent system resulted in good agreements. The potential cocrystal formation of acyclovir was characterized by IR, PXRD and DSC techniques. An in-vitro dissolution study was performed to determine the dissolution rate of cocrystals. The results suggest that acyclovir forms cocrystals with tartaric acid and the initial dissolution rate of synthesized cocrystals were considerably faster as compared to pure acyclovir.
Descritores: Solubilidade
Aciclovir/análise
Parâmetros/classificação
-Solventes/uso terapêutico
Dissolução
Responsável: BR40.1 - DBD - Divisão de Biblioteca e Documentacão do Conjunto das Químicas


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Id: biblio-906060
Autor: Silva, Tânia Mara.
Título: Avaliação da interface adesiva em dentina sadia e afetada por cárie sob pressão pulpar simulada e após desafio em solventes / Evaluation of sound and caries-affected dentin interface under simulated pulpal pressure and aging in food-simulating solvents.
Fonte: São José dos Campos; s.n; 2018. 119 p. il., tab., graf..
Idioma: pt.
Tese: Apresentada a Universidade Estadual Paulista (Unesp), Instituto de Ciência e Tecnologia de São José dos Campos para obtenção do grau de Doutor.
Resumo: O objetivo deste estudo foi avaliar a resistência de união (RU) e características da interface adesiva em dentina sadia e afetada por cárie, na presença de pressão pulpar simulada e após desafio em solventes. Setenta e dois molares humanos hígidos (SD) e outros trinta e seis molares humanos cariados (NCAD) foram seccionados para obtenção de 2 mm de espessura de dentina, a partir do corno pulpar mais alto. Dentre as amostras sadias, trinta e seis foram submetidas à formação artificial de dentina afetada por cárie pelo processo de ciclagem de pH (ACAD). Previamente ao procedimento restaurador, a análise química da superfície oclusal de cinco amostras de cada dentina foi avaliada em espectroscopia de infravermelho por Transformada de Fourier (FTIR) e microdureza de superfície (KHN). Todas as amostras foram tratadas, sob pressão pulpar simulada (20 cm H20), sequencialmente com: ácido fosfórico 37%, sistema adesivo (Scotchbond Universal, 3M/ESPE), fotopolimerização (10 s), confecção de um bloco de resina composta (Filtek Z350 XT; 3M/ESPE) e fotopolimerização (20 s). Após 48 h, palitos retangulares de resina-dentina (1mm2) foram obtidos e aleatoriamente divididos em grupos, de acordo com o tempo de envelhecimento (24 h e 30 dias) e solventes: água deionizada (A), etanol a 99% (E) e metiletilcetona (MEK). As amostras foram submetidas aos testes de resistência adesiva à microtração (0,5 mm/min; 10 kgf), e a interface adesiva avaliada em microscopia eletrônica de varredura (MEV). Os sistemas adesivos foram avaliados frente ao desafio dos solventes, por análise da resistência flexural (RF), módulo de elasticidade (ME), sorção (SO) e solubilidade (SL). Os resultados de RU foram submetidos aos testes ANOVA de medidas repetidas sob 3-fatores (dentina, solvente e tempo de armazenamento), seguido do teste de múltiplas comparações de Tukey (p<0,05). FTIR: diferenças químicas foram observadas entre os substratos, pela perda do conteúdo mineral na NCAD (maior) e ACAD (intermediário) em relação à SD. KHN: NCAD mostrou as menores médias, diferindo significantemente da SD. RU: dentina, tempos, interação dentina-tempo e interação dentina-tempo-solvente mostraram efeitos estatisticamente significantes: SD apresentou diferenças significativas quando armazenada 24 h em A; diferenças significantes foram observadas no grupo NCAD para o solvente E após 30 dias. MEV: as características da interface adesiva diferiram entre os substratos e solventes: A degradou a interface entre dentina e camada de sistema adesivo; E e MEK entre camada de adesivo e resina composta. RF/ME: solvente e tempo foram estatisticamente significantes, com as menores médias para E. SO/SL: A apresentou as menores médias, diferindo significantemente dos demais solventes. Pode-se concluir que o tipo de dentina, o solvente e o tempo de armazenamento interferiram negativamente nos valores de RU, com as menores médias para: NCAD, E em 30 dias; e, as propriedades físico-mecânicas do sistema adesivo foram diretamente afetadas pelo E.(AU)

The aim of this study was to evaluate the bond strength (BS) and adhesive interface characteristics of sound and caries-affected dentin under presence of simulated pulpal pressure (SPP) and after aging in solvents. Seventy-two sound human molars (SD) and thirty-six caries-affected human molars (NCAD) were sectioned to obtain 2-mm dentin thickness from the highest pulp horn. Among the sound dentin samples, thirtysix were submitted to artificial formation of caries by the pH cycling (ACAD). Prior to restorative procedures, chemical analysis of the dentin occlusal surface of five selected samples was performed in Fourier transform infrared spectroscopy (FTIR) and surface microhardness (KHN). All samples were treated, under simulated SPP (20 cm H20), sequentially with: 37% phosphoric acid, adhesive system (Scotchbond Universal, 3M/ESPE), light-cured (10 s), a composite resin build up (Filtek Z350 XT; 3M/ESPE) and light-cured (20 s). After 48 h, tooth-resin sticks (1mm2) were obtained and randomly divided into groups, according to storage time (24 h and 30 days) and solvents: deionized water (W), 99% ethanol (E) and methyl ethyl ketone (MEK). Samples were submitted to microtensile bond strength test (0.5 mm/min; 10 kgf), and the adhesive interface was evaluated by scanning electron microscopy (SEM). The adhesive system was evaluated, against the solvents challenge, by flexural strength (FS), modulus of elasticity (ME), sorption (SO) and solubility (SL). Data were submitted to 3-way ANOVA (dentin, solvent and storage times) followed by Tukey (p<0.05). FTIR: Chemical differences in dentin were observed through mineral content loss in NCAD (higher) and ACAD (intermediate) in relation to SD. KHN:NCAD showed the lowest mean, differing significantly from SD. BS: Dentin, time, interaction dentin-time and interaction dentin-time-solvent had a statistically significant effect: SD showed significant differences when storage 24h in W; statistically significant differences were observed in group NCAD storage 30 days in E. SEM: the characteristics of adhesive interface differs among substrates and aging solvents: W degradated the interface between dentin and adhesive; E and MEK between adhesive and composite resin. FS/ME: solvent and time were statistically significant, with the lowest mean for E. SO/SL: A showed lower means, differing significantly from the other solvents. It can be concluded that the type of dentin, aging solvents and storage time interfered negatively on BS values, with lowest values for: NCAD, E for 30 days; and the physico-mechanical adhesive properties were directly affected by E.(AU)
Descritores: Cárie Dentária/complicações
-Dentina/lesões
Solventes/síntese química
Limites: Humanos
Tipo de Publ: Estudo Comparativo
Responsável: BR243.1 - Serviço Técnico de Biblioteca e Documentação
BR243.1; 1064. 2249


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Id: biblio-893652
Autor: Botelho, Maria Paula Jacobucci; Isolan, Cristina Pereira; Schwantz, Júlia Kaster; Lopes, Murilo Baena; Moraes, Rafael Ratto de.
Título: Rubbing time and bonding performance of one-step adhesives to primary enamel and dentin
Fonte: J. appl. oral sci;25(5):523-532, Sept.-Oct. 2017. tab, graf.
Idioma: en.
Resumo: Abstract Objectives: This study investigated whether increasing the concentration of acidic monomers in one-step adhesives would allow reducing their application time without interfering with the bonding ability to primary enamel and dentin. Material and methods: Experimental one-step self-etch adhesives were formulated with 5 wt% (AD5), 20 wt% (AD20), or 35 wt% (AD35) acidic monomer. The adhesives were applied using rubbing motion for 5, 10, or 20 s. Bond strengths to primary enamel and dentin were tested under shear stress. A commercial etch-and-rinse adhesive (Single Bond 2; 3M ESPE) served as reference. Scanning electron microscopy was used to observe the morphology of bonded interfaces. Data were analysed at p<0.05. Results: In enamel, AD35 had higher bond strength when rubbed for at least 10 s, while application for 5 s generated lower bond strength. In dentin, increased acidic monomer improved bonding only for 20 s rubbing time. The etch-and-rinse adhesive yielded higher bond strength to enamel and similar bonding to dentin as compared with the self-etch adhesives. The adhesive layer was thicker and more irregular for the etch-and-rinse material, with no appreciable differences among the self-etch systems. Conclusion: Overall, increasing the acidic monomer concentration only led to an increase in bond strength to enamel when the rubbing time was at least 10 s. In dentin, despite the increase in bond strength with longer rubbing times, the results favoured the experimental adhesives compared to the conventional adhesive. Reduced rubbing time of self-etch adhesives should be avoided in the clinical setup.
Descritores: Bis-Fenol A-Glicidil Metacrilato/química
Colagem Dentária/métodos
Esmalte Dentário/efeitos dos fármacos
Adesivos Dentinários/química
Dentina/efeitos dos fármacos
Metacrilatos/química
-Análise de Variância
Falha de Restauração Dentária
Glicerol/química
Teste de Materiais
Microscopia Eletrônica de Varredura
Reprodutibilidade dos Testes
Resistência ao Cisalhamento
Solventes/química
Propriedades de Superfície/efeitos dos fármacos
Fatores de Tempo
Água/química
Limites: Humanos
Tipo de Publ: Estudo de Avaliação
Responsável: BR1.1 - BIREME


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Id: biblio-889051
Autor: Oliveira, AR; Campos Neto, AA; de Andrade, MJO; de Medeiros, PCB; dos Santos, NA.
Título: Organic solvent exposure and contrast sensitivity: comparing men and women
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;51(3):e6568, 2018. tab, graf.
Idioma: en.
Resumo: The goal of this study was to compare the visual contrast sensitivity (CS) of men and women exposed and not exposed to organic solvents. Forty-six volunteers of both genders aged between 18 and 41 years (mean±SD=27.72±6.28) participated. Gas station attendants were exposed to gas containing 46.30 ppm of solvents at a temperature of 304±274.39 K, humidity of 62.25±7.59% and ventilation of 0.69±0.46 m/s (a passive gas chromatography-based sampling method was used considering the microclimate variables). Visual CS was measured via the psychophysical method of two-alternative forced choice using vertical sinusoidal gratings with spatial frequencies of 0.2, 0.5, 1.0, 2.0, 5.0, 10.0, and 16.0 cpd (cycles per degree) and an average luminance of 34.4 cd/m2. The results showed that visual CS was significantly lower (P<0.05) in the following groups: i) exposed men compared to unexposed men at frequencies of 0.2, 0.5, 1.0, and 2.0 cpd; ii) exposed women compared to unexposed women at a frequency of 5.0 cpd; and iii) exposed women compared to exposed men at a frequency of 0.5 cpd, even at exposures below the tolerance limit (300 ppm). These results suggest that the visual CS of exposed men was impaired over a wider range of spatial frequencies than that of exposed women. This difference may have been due to the higher body fat content of women compared to that of men, suggesting that body fat in women can serve as a protective factor against neurotoxic effects.
Descritores: Sensibilidades de Contraste/efeitos dos fármacos
Exposição Ocupacional/efeitos adversos
Solventes/efeitos adversos
Percepção Visual/fisiologia
-Tecido Adiposo/anatomia & histologia
Brasil/epidemiologia
Escolaridade
Microclima
Exposição Ocupacional/estatística & dados numéricos
Limiar Sensorial/fisiologia
Fatores Sexuais
Aprendizagem Espacial/fisiologia
Limites: Humanos
Masculino
Feminino
Adulto
Adulto Jovem
Tipo de Publ: Estudo Comparativo
Responsável: BR1.1 - BIREME



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