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Texto completo SciELO Chile
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Id: biblio-1011393
Autor: Waterman, Melinda J; Bramley-Alves, Jessica; Miller, Rebecca E; Keller, Paul A; Robinson, Sharon A.
Título: Photoprotection enhanced by red cell wall pigments in three East Antarctic mosses
Fonte: Biol. Res;51:49, 2018. tab, graf.
Idioma: en.
Projeto: Australian Research Council Discovery Project; . Australian Antarctic Division.
Resumo: BACKGROUND: Antarctic bryophytes (mosses and liverworts) are resilient to physiologically extreme environmental conditions including elevated levels of ultraviolet (UV) radiation due to depletion of stratospheric ozone. Many Antarctic bryophytes synthesise UV-B-absorbing compounds (UVAC) that are localised in their cells and cell walls, a location that is rarely investigated for UVAC in plants. This study compares the concentrations and localisation of intracellular and cell wall UVAC in Antarctic Ceratodon purpureus, Bryum pseudotriquetrum and Schistidium antarctici from the Windmill Islands, East Antarctica. RESULTS: Multiple stresses, including desiccation and naturally high UV and visible light, seemed to enhance the incorporation of total UVAC including red pigments in the cell walls of all three Antarctic species analysed. The red growth form of C. purpureus had significantly higher levels of cell wall bound and lower intracellular UVAC concentrations than its nearby green form. Microscopic and spectroscopic analyses showed that the red colouration in this species was associated with the cell wall and that these red cell walls contained less pectin and phenolic esters than the green form. All three moss species showed a natural increase in cell wall UVAC content during the growing season and a decline in these compounds in new tissue grown under less stressful conditions in the laboratory. CONCLUSIONS: UVAC and red pigments are tightly bound to the cell wall and likely have a long-term protective role in Antarctic bryophytes. Although the identity of these red pigments remains unknown, our study demonstrates the importance of investigating cell wall UVAC in plants and contributes to our current understanding of UV-protective strategies employed by particular Antarctic bryophytes. Studies such as these provide clues to how these plants survive in such extreme habitats and are helpful in predicting future survival of the species studied.
Descritores: Pigmentos Biológicos/efeitos da radiação
Pigmentos Biológicos/metabolismo
Raios Ultravioleta
Parede Celular/efeitos da radiação
Parede Celular/metabolismo
Briófitas/efeitos da radiação
Briófitas/metabolismo
-Estações do Ano
Fatores de Tempo
Pigmentação/efeitos da radiação
Análise de Variância
Cromatografia Líquida de Alta Pressão
Espectroscopia de Infravermelho com Transformada de Fourier/métodos
Folhas de Planta/efeitos da radiação
Folhas de Planta/metabolismo
Microscopia Confocal
Briófitas/citologia
Regiões Antárticas
Responsável: CL1.1 - Biblioteca Central


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Texto completo SciELO Brasil
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Id: biblio-1101284 LILACS-Express
Autor: Said, Farrukh; Moeen, Faisal; Khan, Muhammad Talal; Mansoor, Afsheen; Uzbek, Usman Haider; Alam, Mohammad Khursheed; Siddiqui, Ammar Ahmed.
Título: Cytotoxicity, Morphology and Chemical Composition of Two Luting Cements: An in Vitro Study
Fonte: Pesqui. bras. odontopediatria clín. integr;20:e5434, 2020. tab, graf.
Idioma: en.
Resumo: Abstract Objective: To assess the cytotoxicity, surface morphology, elemental compositions and chemical characterization of two commonly used luting cement. Material and Methods: The two luting types of cement used were Elite Cement® and Hy-Bond Resiglass®. Freshly mixed (n=6) and set form (n=6) of each cement was placed in medium to obtain extracts. The extract from each sample was exposed to L929 mouse fibroblasts (1x104cells/well). Alamar Blue Assay assessed cell viability. Surface morphology and elemental composition were evaluated using scanning electron microscopy and energy dispersive spectroscopy. The chemical characterization was performed by Fourier Transform Infrared Spectroscopy. One-way ANOVA and post-hoc Tukey analysis were conducted to assess results. Results: Hy-Bond Resiglass® was the more cytotoxic of the two types of cement in both freshly mixed (68.10 +5.16; p<0.05) and set state (87.58 +4.86; p<0.05), compared to Elite Cement® both freshly mixed (77.01 +5.45; p<0.05) and set state (89.39 +5.66; p<0.05). Scanning electron microscopy revealed a more irregular and porous structure in Hy-Bond Resiglass® compared to Elite Cement®. Similarly, intense peaks of aluminium, tungsten and fluorine were observed in energy dispersive spectroscopy in Hy-Bond Resiglass. Conclusion: All these three elements (aluminium, tungsten and fluorine) have cytotoxic potential. The Fourier transform infrared spectroscopy revealed the presence of hydroxyethyl methacrylate in Hy-Bond Resiglass®, which has a cytotoxic potential.
Descritores: Cimento de Fosfato de Zinco
Técnicas In Vitro/métodos
Cimentos Dentários
Fibroblastos
-Paquistão
Ratos
Análise Espectral
Tungstênio
Microscopia Eletrônica de Varredura
Análise de Variância
Espectroscopia de Infravermelho com Transformada de Fourier
Limites: Animais
Camundongos
Ratos
Tipo de Publ: Estudo Comparativo
Estudo de Avaliação
Responsável: BR1264.1 - Biblioteca Setorial Prof Alberto M Campos


  3 / 140 LILACS  
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Id: biblio-1141502
Autor: Alhamdani, Ammar AG; Shuker, Arjwan M; Jawad, Inas A.
Título: Antibacterial activity and effects of aromatic derivatives on denture base polymerization
Fonte: J. oral res. (Impresa);8(supl.1):24-27, ago. 9, 2019. tab, ilus.
Idioma: en.
Resumo: This study assessed the effect of copolymerization on the microbiota of the oral cavity. The plant extraction was converted into aromatic derivatives, which were added to methyl methacrylate monomer. Fourier transform infrared spectroscopy spectra showed no negative effects of these additives on the polymerization process. All the assayed derivatives displayed some degree of antibacterial activity.
Descritores: Eugenol/análise
Bases de Dentadura
Microbiota
-Resinas Sintéticas
Espectroscopia de Infravermelho com Transformada de Fourier
Polimerização
Anti-Infecciosos/isolamento & purificação
Limites: Humanos
Responsável: CL30.1 - Biblioteca


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Id: biblio-1141501
Autor: Hasan, Nadia H; Nayif, Ma'an M; Taqa, Amer A.
Título: FTIR and SEM of a novel chemical conditioning on the zirconia intaglio surface
Fonte: J. oral res. (Impresa);8(supl.1):19-23, ago. 9, 2019. ilus.
Idioma: en.
Resumo: Objectives: The aim of this study was to evaluate chemical and topographical changes in the intaglio zirconia surface induced by chemical conditioning solutions using FTIR and SEM analysis. Material and method: twelve plates for each FTIR and SEM tests from each zirconia materials (UPCERA HT White, BruxZir® Solid Zirconia, and Copran® Multilayer), milled by a Yenadent CAD/CAM system, sintered and divided randomly into a three groups. A different surface conditioning was applied to the intaglio surface of each group: 30% hydrogen peroxide, 30% citric acid and control group. Result and discussion: by using of the FTIR spectroscopy, an evidence of new bands formation appeared at 1637cm-1 and 3352cm-1 due to the high oxidizing effect of hydrogen peroxide, and at 630cm-1 and 1663cm-1 due to the chelating action of citric acid, and simultaneously, SEM assessment of the surface topography took place, to identify lines, scratches, or surface dissociation that appeared on the intaglio zirconia surface after conditioning. Conclusion: such analysis provides an enhancement of new convenient, less expensive, reliable trials to improve micro-bond strength of luting cement to Y-TZP ceramics.
Descritores: Resinas Sintéticas
Zircônio/análise
Espectroscopia de Infravermelho com Transformada de Fourier/métodos
-Microscopia Eletrônica de Varredura
Cimentos Dentários
Peróxido de Hidrogênio
Limites: Humanos
Responsável: CL30.1 - Biblioteca


  5 / 140 LILACS  
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Id: biblio-1053195
Autor: Olasehinde, Tosin A; Odjadjare, Ejovwokoghene C; Mabinya, Leonard V; Olaniran, Ademola O; Okoh, Anthony I.
Título: Chlorella sorokiniana and Chlorella minutissima exhibit antioxidant potentials, inhibit cholinesterases and modulate disaggregation of ß-amyloid fibrils
Fonte: Electron. j. biotechnol;40:1-9, July. 2019. tab, graf, ilus.
Idioma: en.
Resumo: BACKGROUND: Microalgae are aquatic chlorophyll-containing organisms comprising unicellular microscopic forms, and their biomasses are potential sources of bioactive compounds, biofuels and food-based products. However, the neuroprotective effects of microalgal biomass have not been fully explored. In this study, biomass from two Chlorella species was characterized, and their antioxidant, anticholinesterase and anti-amyloidogenic activities were investigated. RESULTS: GC­MS analysis of the extracts revealed the presence of some phenols, sterols, steroids, fatty acids and terpenes. Ethanol extract of Chlorella sorokiniana (14.21 mg GAE/g) and dichloromethane extract of Chlorella minutissima (20.65 mg QE/g) had the highest total phenol and flavonoid contents, respectively. All the extracts scavenged 2,2-diphenyl-1-picrylhydrazyl, 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonate) and hydroxyl radicals. The highest metal chelating activity of the extracts was observed in the ethanol extracts of C. minutissima (102.60 µg/mL) and C. sorokiniana (107.84 µg/mL). Furthermore, the cholinesterase inhibitory activities of the extracts showed that ethanol extract of C. sorokiniana (13.34 µg/mL) exhibited the highest acetylcholinesterase inhibitory activity, while dichloromethane extract of C. minutissima (11.78 µg/mL) showed the highest butyrylcholinesterase inhibitory activity. Incubation of the ß-amyloid protein increased the aggregation of amyloid fibrils after 96 h. However, ethanol extract of C. sorokiniana and C. minutissima inhibited further aggregation of Aß1­42 and caused disaggregation of matured protein fibrils compared to the control. This study reveals the modulatory effects of C. sorokiniana and C. minutissima extracts on some mediators of Alzheimer's disease and provides insights into their potential benefits as functional food, nutraceutics or therapeutic agent for the management of this neurodegenerative disease.
Descritores: Chlorella/química
Inibidores da Colinesterase/farmacologia
Peptídeos beta-Amiloides/antagonistas & inibidores
Antioxidantes/farmacologia
-Fenóis/análise
Esteroides/análise
Esteróis/análise
Terpenos/análise
Extratos Vegetais/farmacologia
Extratos Vegetais/química
Inibidores da Colinesterase/química
Espectroscopia de Infravermelho com Transformada de Fourier
Fármacos Neuroprotetores
Biomassa
Etanol
Ácidos Graxos/análise
Microalgas
Doença de Alzheimer/prevenção & controle
Amiloide/efeitos dos fármacos
Cromatografia Gasosa-Espectrometria de Massas
Antioxidantes/química
Responsável: CL1.1 - Biblioteca Central


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Texto completo SciELO Brasil
Amaral, Cristiane Mariote
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Id: biblio-1101251
Autor: MIRANDA, Maria Elisa da Silva Nunes Gomes; SILVA, Eduardo Moreira da; OLIVEIRA, Mariana Flôres de; SIMMER, Fabiana Souza; SANTOS, Glauco Botelho dos; AMARAL, Cristiane Mariote.
Título: Resin-dentin bond stability of etch-and-rinse adhesive systems with different concentrations of MMP inhibitor GM1489
Fonte: J. appl. oral sci;28:e20190499, 2020. tab, graf.
Idioma: en.
Projeto: CAPES.
Resumo: Abstract Enzymatic degradation of the hybrid layer can be accelerated by the activation of dentin metalloproteinases (MMP) during the bonding procedure. MMP inhibitors may be used to contain this process. Objective To evaluate the degree of conversion (DC%), dentin bond strength (µTBS) (immediate and after 1 year of storage in water), and nanoleakage of an experimental (EXP) and a commercial (SB) adhesive system, containing different concentrations of the MMP inhibitor GM1489: 0, 1 µM, 5 µM and 10 µM. Methodology DC% was evaluated by FT-IR spectroscopy. Dentin bond strength was evaluated by µTBS test. Half of beams were submitted to the µTBS test after 24 h and the other half, after storage for 1 year. From each tooth and storage time, 2 beams were reserved for nanoleakage testing. Data were analyzed using ANOVA and Tukey's test to compare means (α=0.05). Results All adhesive systems maintained the µTBS after 1 year of storage. Groups with higher concentrations of inhibitor (5 µM and 10 µM) showed higher µTBS values than groups without inhibitor or with 1 µM. The nanoleakage values of all groups showed no increase after 1 year of storage and values were similar for SB and EXP groups, in both storage periods. The inhibitor did not affect the DC% of the EXP groups, but the SB5 and SB10 groups showed higher DC% values than those of SB0 and SB1. Conclusions The incorporation of GM1489 in the adhesive systems had no detrimental effect on DC%. The concentrations of 5 µM GM1489 for SB and 5 µM or 10 µM for EXP provided higher μTBS than groups without GM1489, in the evaluation after 1 year of storage; whereas the concentration of inhibitor did not affect adhesive systems nanoleakage.
Descritores: Polietilenoglicóis/química
Ácidos Polimetacrílicos/química
Cimentos Dentários/química
Dentina/química
Inibidores de Metaloproteinases de Matriz/química
Metacrilatos/química
-Valores de Referência
Propriedades de Superfície
Resistência à Tração
Fatores de Tempo
Teste de Materiais
Reprodutibilidade dos Testes
Análise de Variância
Colagem Dentária/métodos
Espectroscopia de Infravermelho com Transformada de Fourier
Estatísticas não Paramétricas
Infiltração Dentária
Dentina/efeitos dos fármacos
Corrosão Dentária/métodos
Limites: Humanos
Tipo de Publ: Estudo de Avaliação
Responsável: BR28.1 - Serviço de Biblioteca e Documentação Professor Doutor Antônio Gabriel Atta


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Id: biblio-1090769
Autor: Maluf, Caroline Vieira; Peroni, Luciana Vieira; Menezes, Lívia Rodrigues; Coutinho, Wagner; Lourenço, Eduardo José Veras; Telles, Daniel de Moraes.
Título: Evaluation of the physical and antifungal effects of chlorhexidine diacetate incorporated into polymethyl methacrylate
Fonte: J. appl. oral sci;28:e20190039, 2020. tab, graf.
Idioma: en.
Resumo: Abstract This study aimed to evaluate the physical properties and antifungal activities of polymethyl methacrylate (PMMA) acrylic resins after the incorporation of chlorhexidine diacetate salt (CDA). Methodology: First, acrylic resin specimens were fabricated with Vipi Cor® and DuraLay® resins with and without the incorporation of 0.5%, 1.0% or 2.0% CDA. The residual monomer and CDA release were measured at intervals ranging from 2 hours to 28 days using ultraviolet spectrometry combined with high-performance liquid chromatography. The antifungal activity against C. albicans was evaluated with the agar diffusion method. Fourier transform infrared spectroscopy was used to analyze the degree of resin conversion. Finally, the water sorption values of the resins were also measured. Results: The incorporated CDA concentration significantly changed the rate of CDA release (p<0.0001); however, the brand of the material appeared to have no significant influence on drug release. Subsequently, the inhibition zones were compared between the tested groups and within the same brand, and only the comparisons between the CDA 2% and CDA 1% groups and between the CDA 1% and CDA 0.5% groups failed to yield significant differences. Regarding the degrees of conversion, the differences were not significant and were lower only in the CDA 2% groups. Water sorption was significantly increased at the 1.0% and 2.0% concentrations. Conclusions: We concluded that the incorporation of CDA into PMMA-based resins enabled the inhibition of C. albicans growth rate, did not alter the degrees of conversion of the tested resins and did not change the release of residual monomers.
Descritores: Clorexidina/análogos & derivados
Polimetil Metacrilato/química
Antifúngicos/química
-Valores de Referência
Fatores de Tempo
Resinas Acrílicas/química
Teste de Materiais
Candida albicans/efeitos dos fármacos
Água/química
Clorexidina/farmacologia
Reprodutibilidade dos Testes
Cromatografia Líquida de Alta Pressão
Espectroscopia de Infravermelho com Transformada de Fourier
Polimetil Metacrilato/farmacologia
Antifúngicos/farmacologia
Tipo de Publ: Estudo de Avaliação
Responsável: BR28.1 - Serviço de Biblioteca e Documentação Professor Doutor Antônio Gabriel Atta


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Id: lil-529293
Autor: Arrais, César Augusto Galvão; Urban, Vanessa Migliorini; Pontes, Fenelon Martinho Lima; Leite, Edson Roberto; Giannini, Marcelo.
Título: Influence of curing accelerator for cyanoacrylate glues on physical properties of adhesive resins
Fonte: RPG rev. pos-grad;13(1):7-12, jan.-mar. 2006. tab, graf.
Idioma: en.
Resumo: The objectives of this study were to evaluate the effect of a curing accelerator (CA) on the ultimate tensile strength (UTS) and degree of conversion (DC) of two adhesive systems, Single Bond and Clearfil SE Bond, as well as to identify the composition of the CA hour-glass adhesive resin samples with a cross sectional area of 0,8 mm² at the "neck" were tested in tension using a Universal Testing Machine. Fourier transform infrared spectroscopy (FTIR) was used to analyse thin films of each adhesive resin. All samples were stored in the dark for 24 hours before they were tested. During the UTS and FTIR analyses, the contact of the CA with samples was either avoided or not. The gas chromatography mass spectrocopy (GC-MS) and the nuclear magnetic resonance (NMR) analyses determined the molecular weight and structure of the CA. UTS and DC were analyzed by ANOVA and Tukey's test at 95% of confidence. The use of the CA did not affect the UST (p=0.5996) but increased the DC of the samples (p<0.0001). The compound identified by GC-MS and NMR was N-dimethyl p-toluidine. The application of CA in microtensile bond strength methodology raises concern regarding its effects on poorly polymerized adhesive systems.
Descritores: Adesivos Dentinários
Resistência à Tração
-Análise de Variância
Cromatografia Gasosa
Espectroscopia de Infravermelho com Transformada de Fourier
Tipo de Publ: Estudo de Avaliação
Responsável: BR501.1 - Biblioteca de Ciências da Saúde / Sede Botânico


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Texto completo SciELO Brasil
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Id: biblio-1019409
Autor: Agra, Lydianne Lumack do Monte; Melo, Gustavo Barreto; Lima Filho, Acácio Alves Souza; Ota, Shoko; Maia, Maurício.
Título: Silicone oil found in syringes commonly used for intravitreal injections / Óleo de silicone encontrado em seringas comumente usadas para injeções intravítreas
Fonte: Arq. bras. oftalmol;82(4):354-355, July-Aug. 2019. graf.
Idioma: en.
Descritores: Siloxanas/análise
Seringas/normas
Óleos de Silicone/análise
Injeções Intravítreas/instrumentação
-Valores de Referência
Siloxanas/química
Vibração
Teste de Materiais
Óleos de Silicone/química
Fatores de Risco
Espectroscopia de Infravermelho com Transformada de Fourier
Tipo de Publ: Research Support, Non-U.S. Gov't
Carta
Responsável: BR1.1 - BIREME


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Id: biblio-1121858
Autor: Topbasi, Nuri Mert; Benkli, Yasin Atakan.
Título: Evaluation of the bond strength of orthodontic brackets and the degree of polymerisation and microhardness of an orthodontic adhesive using polywave light curing unit and varying light densities / Avaliação da resistência de união, grau de polimerização e microdureza de um adesivo para colagem de bráquetes ortodônticos utilizando unidade de polimerização polywave e densidades de luz variáveis
Fonte: Braz. dent. sci;23(4):1-9, 2020. tab, ilus.
Idioma: en.
Resumo: Objective: This study evaluates the shear bond strength (SBS) and Vickers micro-hardness (VHN) of the orthodontic adhesive resin Transbond XT using thermocycled samples. The study also measures the degree of cure by poliwave light curing unit Valo. Materials and Methods: 135 brackets were bonded for the SBS test, and 90 disc-shaped orthodontic adhesive resins were prepared for the VHN test. The measurements were taken either immediately or after 500 or 10.0000 thermocycling. The SBS and VHN test data were statistically evaluated using a Two-way ANOVA and Tukey multiple comparison tests. The degree of conversion (DC) was measured by FTIR. Results: The 10-sec polymerized control group (57.08) and the 10.000 termocycled samples (55.96) had the highest VHN scores. On the other hand, the 3 second polymerized and the 10.000 termocycled samples (39.22) had the lowest VHN scores. There was no significant difference in the bracket SBS values between the termocycled and immediate groups. An evaluation of the bond failure surfaces revealed that the ARI scores did not differ between the immediate and the thermo-cycled groups according to the power modes. The FTIR results revealed that the lowest DC was seen in the 3 second light-cured sample. Conclusion: TransbondXT provided sufficient bond strength, microhardness and DC under in vitro bracket bonding conditions after 3 and 10 s of Poliwave LED curing. However, low mean values were seen in the groups that received Poliwave LED curing for only 3 s (AU)

Objetivo: Este estudo avalia a resistência ao cisalhamento (SBS) e a microdureza Vickers (VHN) da resina adesiva ortodôntica Transbond XT utilizando amostras termocicladas. O estudo também mede o grau de cura pela unidade de fotopolimerização Valo poliwave. Materiais e Métodos: 135 braquetes foram colados para o teste SBS e 90 discos de resina adesiva ortodôntica foram preparados para o teste VHN. As medições foram feitas imediatamente ou após 500 ou 10.000 ciclos de termociclagem. Os dados dos testes SBS e VHN foram avaliados estatisticamente usando ANOVA 2 fatores e teste de comparação múltipla de Tukey. O grau de conversão (DC) foi medido por FTIR. Resultados: O grupo controle polimerizado por 10segundos (57,08) ciclados por 10.000 ciclos (55,96) tiveram os valores VHN mais altos. Por outro lado, as amostras polimerizadas de 3 segundos e 10.000 ciclos (39,22) os valores de VHN mais baixos. Não houve diferença significativa nos valores de SBS do braquete entre os grupos termociclados e imediato. Uma avaliação das superfícies de falha de adesão revelou que os escores do ARI não diferiram entre os grupos imediato e termociclados de acordo com as densidades de potência. Os resultados do FTIR revelaram que o menor DC foi observado nas amostras fotopolimerizadas de 3 segundos. Conclusão: Transbond XT forneceu suficiente resistência de união, microdureza e DC sob condições de colagem de braquetes in vitro após 3 e 10 s de polimerização em LED Poliwave. No entanto, valores médios baixos foram observados nos grupos que receberam a cura do LED Poliwave por apenas 3 s (AU)
Descritores: Ortodontia
Espectroscopia de Infravermelho com Transformada de Fourier
Resistência ao Cisalhamento
Lasers Semicondutores
Tipo de Publ: Artigo Clássico
Responsável: BR243.1 - Serviço Técnico de Biblioteca e Documentação



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