RESUMO
Diabetic-metabolic syndrome (MetS-D) has a high prevalence worldwide, in which an association with the rupture of the intestinal epithelium barrier function (IEBF) has been pointed out, but the functional and morphological properties are still not well understood. This study aimed to evaluate the impact of acute hyperglycemia diabetes on intestinal tight junction proteins, metabolic failure, intestinal ion and water transports, and IEBF parameters. Diabetes was induced in male Rattus norvegicus (200-310 g) with 0.5 mL of streptozotocin (70 mg/kg). Glycemic and clinical parameters were evaluated every 7 days, and intestinal parameters were evaluated on the 14th day. The MetS-D animals showed a clinical pattern of hyperglycemia, with increases in the area of villi and crypts, lactulose:mannitol ratio, myeloperoxidase (MPO) activity, and intestinal tissue concentrations of malondialdehyde (MDA), but showed a reduction in reduced glutathione (GSH) when these parameters were compared to the control. The MetS-D group had increased secretion of Na+, K+, Cl-, and water compared to the control group in ileal tissue. Furthermore, we observed a reduction in mRNA transcript of claudin-2, claudin-15, and NHE3 and increases of SGLT-1 and ZO-1 in the MetS-D group. These results showed that MetS-D triggered intestinal tissue inflammation, oxidative stress, complex alterations in gene regulatory protein transcriptions of intestinal transporters and tight junctions, damaging the IEBF and causing hydroelectrolyte secretion.
Assuntos
Diabetes Mellitus Experimental , Hiperglicemia , Mucosa Intestinal , Junções Íntimas , Animais , Masculino , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Diabetes Mellitus Experimental/metabolismo , Hiperglicemia/metabolismo , Junções Íntimas/metabolismo , Ratos , Inflamação/metabolismo , Modelos Animais de Doenças , Ratos Wistar , Síndrome Metabólica/metabolismo , Síndrome Metabólica/fisiopatologiaRESUMO
This retrospective cohort study aimed to identify risk factors for the failure of transfer of passive immunity (FPI) in preweaned dairy calves, explore its associations with morbidity, mortality, genetics, and determine a standardized cut-off point for FPI. Analyzing data from 6011 calves, factors such as sire predicted transmitted ability for milk (PTA), birth season, retained placenta (RP), total serum protein concentration (TSP), morbidity (neonatal calf diarrhea - NCD, bovine respiratory disease - BRD, tick-borne disease - TBD), mortality, and average daily weight gain (ADG) were considered. The calves were categorized into predominantly Gyr (PG) and predominantly Holstein (PH) genetic composition groups. Multivariate mixed logistic regression revealed optimal TSP cut-off points for predicting morbidity (7.6 g/dL) and mortality (6.9 g/dL). PH calves exhibited 1.35 times higher odds of FPI and 1.48 times greater odds of disease. Calves from multiparous cows and those born to dams with RP had increased FPI odds. Disease prevalence was 53%, with 41% NCD, 18% BRD, and 10% TBD. Season, parity, PTA, and birth weight were associated with disease odds, though FPI was not a reliable predictor. The mortality percentage was 6%, with PH calves and those with a positive PTA having higher odds. The ADG was 0.64 kg, and FPI-affected calves gained less weight. The study compared and identified various risk factors that potentially impact calf immunity. However, the use of a standardized cut-off point for FPI assessment was not effective in predicting morbidity and mortality at this specific farm.
Assuntos
Doenças dos Bovinos , Doenças não Transmissíveis , Humanos , Gravidez , Feminino , Animais , Bovinos , Doenças não Transmissíveis/veterinária , Estudos Retrospectivos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/genética , Leite , Fatores de RiscoRESUMO
Abstract Diabetic-metabolic syndrome (MetS-D) has a high prevalence worldwide, in which an association with the rupture of the intestinal epithelium barrier function (IEBF) has been pointed out, but the functional and morphological properties are still not well understood. This study aimed to evaluate the impact of acute hyperglycemia diabetes on intestinal tight junction proteins, metabolic failure, intestinal ion and water transports, and IEBF parameters. Diabetes was induced in male Rattus norvegicus (200-310 g) with 0.5 mL of streptozotocin (70 mg/kg). Glycemic and clinical parameters were evaluated every 7 days, and intestinal parameters were evaluated on the 14th day. The MetS-D animals showed a clinical pattern of hyperglycemia, with increases in the area of villi and crypts, lactulose:mannitol ratio, myeloperoxidase (MPO) activity, and intestinal tissue concentrations of malondialdehyde (MDA), but showed a reduction in reduced glutathione (GSH) when these parameters were compared to the control. The MetS-D group had increased secretion of Na+, K+, Cl-, and water compared to the control group in ileal tissue. Furthermore, we observed a reduction in mRNA transcript of claudin-2, claudin-15, and NHE3 and increases of SGLT-1 and ZO-1 in the MetS-D group. These results showed that MetS-D triggered intestinal tissue inflammation, oxidative stress, complex alterations in gene regulatory protein transcriptions of intestinal transporters and tight junctions, damaging the IEBF and causing hydroelectrolyte secretion.
RESUMO
In this work, the natural flower extracted dyes containing luteolin were prepared using three different specimens from daisy flowers family (Leucanthemum vulgare), namely yellow daisy, purple daisy and wine daisy, according to the color of its petals. Moreover, DSSCs were fabricated using nanosized titanium dioxide (TiO2) as an anode; for the photocathodes, two different specimens were used: i) graphite electrode and ii) platinum electrode. To recognize the light absorption behavior, the existence of anchoring groups and coloring components of the extracted dyes were determined using absorption spectroscopy. The surface roughness of the photoanodes and cathodes were examined using atomic force microscope (AFM). The photovoltaic performance and efficiency of assembled DSSCs were evaluated to realize the influence of TiO2 photoanodes on interaction of the Leucanthemum vulgare extracted dye molecules with graphite or platinum photocathodes. DSSCs fabricated with platinum cathode show higher conversion efficiency (η) of 0.6%, 0.4% and 0.8% for the yellow daisy, wine daisy and purple daisy, respectively. DSSCs sensitized with daisy wine dye showed highest open-circuit voltage (Voc) of 520 mV and efficiency of 0.79% and 0.88%, for the graphite and platinum cathodes, respectively. These results showed that the DSSCs, using daisy flowers extracts as efficient photosensitizers, are suitable for the fabrication of environmentally safe, inexpensive, clean and renewable energy.
Assuntos
Asteraceae/química , Fontes de Energia Elétrica , Flores/química , Pigmentos Biológicos , Energia Solar , Eletrodos , Pigmentos Biológicos/química , Pigmentos Biológicos/isolamento & purificação , Titânio/químicaRESUMO
BACKGROUND AND OBJECTIVES: Primary skin cancer prevention campaigns are essential and more effective among children, not only because of the importance of sun exposure effects during this period, but also because this age is when individuals are developing behaviours. The Brazilian Society of Dermatology - Regional State of Sao Paulo developed and conducted the programme named 'The Sun, Friend of Childhood', a school health education and disease prevention project for children and parents. Our objective was to evaluate the cognitive and behavioural effects of the children and parents before and after an education model-based intervention of sun protection. METHODS: We carried out a study on a school population of Social Service of Industry - Regional State of São Paulo, from the first to the fifth years of the regular course (6-10 years). Our educational project was planned to be based on two children's learning tools (comic magazine and a DVD cartoon). Questionnaires in relation to habits and knowledge in sun exposure were applied to the children (3776) before and (2748) after the intervention. A questionnaire was applied to 3663 parents regarding personal details and habits of their children. RESULTS: According to the McNemar's statistical test, all changes in the children in acquiring new knowledge about good practices for sun exposure were statistically significant. CONCLUSIONS: Educative sun exposure programmes in childhood are a relevant tool to modify the history of life for next generations, to concern the skin cancer and good health practices.
Assuntos
Comportamentos Relacionados com a Saúde , Educação em Saúde/métodos , Conhecimentos, Atitudes e Prática em Saúde , Neoplasias Cutâneas/prevenção & controle , Adolescente , Brasil , Desenhos Animados como Assunto , Criança , Pré-Escolar , Cognição , Humanos , Pais , Avaliação de Programas e Projetos de Saúde , Instituições Acadêmicas , Luz Solar/efeitos adversos , Inquéritos e QuestionáriosRESUMO
Estrogen reduction is associated with a decline in skeletal muscle mitochondrial biogenesis. Molecular events associated with improvements in markers of mitochondrial biogenesis after resistance training and estradiol replacement are unknown. This study aimed to investigate the effects of ovariectomy, resistance training, and estradiol replacement on markers of mitochondrial biogenesis and protein expression related to oxidative capacity in the rat gastrocnemius pool. Estradiol replacement was performed using Silastic(®) capsules. During the 12-week resistance training, animals climbed a ladder with weights attached to their tails. Gene expression was analysed by RT-PCR, and protein content was determined by western blotting. Ovariectomy decreased the gene expression of the mitochondrial biogenesis markers PGC-1α (~73%), NRF-1 (~44%), and TFAM (~53%) (p<0.05) and decreased the protein expression of phosphorylated AMPK, CREB and AKT, which are related to oxidative capacity. Resistance training increased PGC-1α (~59%) and TFAM (~48%) expression compared to the Ovariectomy-Sedentary group. The combination of resistance training and estradiol replacement was superior to the ovariectomy-sedentary and ovariectomy-resistance training treatments regarding the gastrocnemius muscle. Estrogen deficiency altered the expression of genes and proteins that favour the development of a mitochondrial dysfunction phenotype, which was improved with resistance training and was partially improved by estradiol replacement.
Assuntos
Músculo Esquelético/fisiologia , Biogênese de Organelas , Condicionamento Físico Animal/fisiologia , Treinamento Resistido , Animais , Western Blotting , Estradiol/administração & dosagem , Estrogênios/deficiência , Feminino , Regulação da Expressão Gênica/fisiologia , Ovariectomia , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Comportamento SedentárioRESUMO
Cellulase is one of the enzymes most commonly used in the textile industry for the biopolishing process. The appropriate choice of pretreatment is a possible route to promoting enzymatic attack in situations in which this is not favored due to the effects of packing. In order to evaluate the influence of pretreatment the yarn was maintained in water for 24h before biopolishing to promote greater spacing between the chains. In the tensile testing the pretreated Combed 13/1 yarn showed a greater percentage reduction in the maximum breaking force following biopolishing, evidencing a stronger enzymatic attack. Also, the Combed 13/1 and OE 14/1 yarns without pretreatment had an approximately 22% reduction in the shrinkage and after pretreatment the Carded 13/1 yarn had the best shrinkage reduction values (18%). These data demonstrate that the introduction of the pretreatment promotes a change in the access of the enzyme to the fiber.
Assuntos
Celulase/química , Celulose/química , Gossypium/química , Óleos Industriais , Resistência à Tração , Fibra de Algodão/métodos , Ensaios Enzimáticos , Teste de Materiais/métodos , Microfibrilas/química , Estresse Mecânico , Água/químicaRESUMO
Los mini-implantes son en la actualidad una herramienta ideal para obtener un anclaje máximo y solucionar un sinfín de problemas clínicos ortodóncicos. Son dispositivos fabricados con titanio grado V (Ti-6AI-4V), que los vuelve más resistentes a la fractura y menos propensos a la oseointegración. El siguiente trabajo tuvo como objetivo reunir diversos estudios de la literatura actual sobre los mini-implantes, para facilitar el entendimiento del asunto al ortodoncista clínico y odontólogos interesados en conocer este dispositivo. Este trabajo reunió estudios en relación a los aspectos clínicos y estructurales de los mini-implantes. Se hizo hincapié en los aspectos estructurales de los mini-implantes, ya que la literatura es escasa en este sentido. Se concluyó que los mini-implantes son dispositivos de anclaje temporario muy útiles en el tratamiento ortodóncico. Siguiendo las orientaciones establecidas y confeccionados de materiales estandarizados internacionalmente, los mini-implantes pueden ser usados en forma segura en seres humanos
Nowadays, the mini-implants are an ideal tool to obtain maximum anchorage solving an endless number of clinical orthodontic problems. These devices are made by titanium grade V (Ti-6Al-4V), which makes them more resistant to breakage and less inclined to osseointegration. By bringing together many studies on the mini-implants' current literature, this article aimed the understanding of the clinical orthodontists and dentists interested in work with this device. The topics are related with the biological, surgical and structural mini-implants. This article emphasized the structural aspects of the mini-implants because the literature is scarce in this important topic. The conclusion was that mini-implants are a temporary anchorage devices very useful in the orthodontic treatment. If followed the guidelines established and using manufactured materials internationally standardized, mini-implants can be used safely in humans
Assuntos
Humanos , Masculino , Feminino , Implantes Dentários , Procedimentos de Ancoragem Ortodôntica , Materiais Dentários , OrtodontiaRESUMO
The aim of this work was to determine the composition of the fish assemblage of Passa Cinco stream and verify changes in their structure on the altitudinal gradient. Six samples were performed at five different sites in Passa Cinco stream (from the headwater, at order two, to its mouth, at order six), using an electric fishery equipment and gill nets in May, July, September and November of 2005 and January and March of 2006. The indices of Shannon's diversity, Pielou's evenness and Margalef's richness were quantified separately considering the different fishery equipment (nets versus electric fishery equipment). An ANOVA was used to compare samples collected in relation to values of abundance, diversity, evenness and richness. The representativeness of the species was summarised by their average values of abundance and weight. We captured 5082 individuals distributed into 61 species. We observed a trend of increasing diversity, richness and evenness of species from site 1 to 3, with further decrease in sites 4 and 5. The values found for habitat diversity also followed this pattern. Significant differences were found for all three indices considering the electric fishery samples. For individuals caught with nets, only the richness index showed a significant difference. Characidium aff. zebra was an important species in the headwater and transition sites and Hypostomus strigaticeps in middle-lower course sites. Despite the small extension of the Passa Cinco stream, environments structurally well defined were evidenced by the species distribution and assemblage composition along the gradient.
Assuntos
Biodiversidade , Peixes/classificação , Animais , Brasil , Densidade Demográfica , Rios , Estações do AnoRESUMO
Ultrasound-guided biliary drainage is a new and effective method for relieving obstructive lesions of the biliary tract. In the hands of experienced operators, ultrasound-guided diversion of the mid portion of the common bile duct and the duodenal bulb is a feasible strategy for the relief of jaundice secondary to distal obstruction (distal bile duct tumors, pancreatic head cancer, or major duodenal papillary tumor), with low morbidity and mortality rates. The technical aspects of the procedure and its indications are reviewed herein, emphasizing its performance in institutions equipped with experienced personnel adhering to strict study protocols.
Assuntos
Coledocostomia/métodos , Colestase/cirurgia , Endossonografia , Colestase/etiologia , HumanosRESUMO
BACKGROUND: Here, we investigated the phylogenetic relationships of the HIV-1 subtype F1 circulating in Angola with subtype F1 strains sampled worldwide and reconstructed the evolutionary history of this subtype in Central Africa. METHODS: Forty-six HIV-1-positive samples were collected in Angola in 2006 and subtyped at the env-gp41 region. Partial env-gp120 and pol-RT sequences and near full-length genomes from those env-gp41 subtype F1 samples were further generated. Phylogenetic analyses of partial and full-length subtype F1 strains isolated worldwide were carried out. The onset date of the subtype F1 epidemic in Central Africa was estimated using a Bayesian Markov chain Monte Carlo approach. RESULTS: Nine Angolan samples were classified as subtype F1 based on the analysis of the env-gp41 region. All nine Angolan sequences were also classified as subtype F1 in both env-gp120 and pol-RT genomic regions, and near full-length genome analysis of four of these samples confirmed their classification as "pure" subtype F1. Phylogenetic analyses of subtype F1 strains isolated worldwide revealed that isolates from the Democratic Republic of Congo (DRC) were the earliest branching lineages within the subtype F1 phylogeny. Most strains from Angola segregated in a monophyletic group together with Romanian sequences; whereas South American F1 sequences emerged as an independent cluster. The origin of the subtype F1 epidemic in Central African was estimated at 1958 (1934-1971). CONCLUSION: "Pure" subtype F1 strains are common in Angola and seem to be the result of a single founder event. Subtype F1 sequences from Angola are closely related to those described in Romania, and only distantly related to the subtype F1 lineage circulating in South America. Original diversification of subtype F1 probably occurred within the DRC around the late 1950s.
Assuntos
Infecções por HIV/virologia , HIV-1/classificação , HIV-1/genética , Filogenia , Angola , Proteínas do Vírus da Imunodeficiência Humana/genética , Humanos , Dados de Sequência Molecular , Romênia , Fatores de TempoRESUMO
The literature on species abundance models is extensive and a great deal of new and important contributions have been published in the last three decades. Broadly speaking, one can recognize five families of species abundance models: i) purely statistical or classic models (Broken-stick, Log-normal, Logarithmic and Geometric series); ii) branching process (Zipf-Mandelbrot and Fractal branching models); iii) population dynamics (Neutral models included); iv) spatial distribution of individuals (Multifractal and HEAP models) and v) niche partitioning (Sugihara's breakage and Tokeshi models). Among these the neutral, the classic and the niche partitioning models have been the most applied to natural communities, the former having been more extensively discussed than the others in the last years. The objective of this paper is to comment some aspects of the classic, neutral and niche partitioning models in a way that the proposed distributions may contribute to the analysis of the empirical patterns of species abundance. In spite of the variety of models, the distributions in general vary between the log-normal and the logarithmic series. From these models the Power-Fraction, together with independent niche dimensions measures, are amenable to experimental tests and may offer answers on which resources are important in the structuring of biological communities.
A literatura sobre modelos de espécie-abundância é extensa e importantes contribuições têm sido publicadas nas últimas três décadas. De forma geral, são reconhecidos cinco grandes grupos de modelos: i) os que descrevem distribuições puramente estatísticas ou modelos clássicos (Broken-stick, log-normal, série logarítmica e série geométrica); ii) os que simulam processos de ramificação hierárquica (modelos Zipf-Mandelbrot e Fractal); iii) de dinâmica de populações (modelos Neutros); iv) de distribuição espacial de indivíduos (modelos Multifractal e HEAP); e v) de partição de nicho (modelos de Sugihara e de Tokeshi). Os modelos clássicos, os de partição de nicho e principalmente os modelos neutros têm sido os mais utilizados em estudos de comunidades naturais. O objetivo deste artigo é discutir de que forma as distribuições geradas por estes três grupos, bem com as suas bases conceituais, podem contribuir com a análise de padrões empíricos de espécie-abundância. Em geral, estes padrões variam entre as curvas log-normal e série logarítmica. Dentre a variedade de modelos existentes, o Power-fraction possibilita a simulação de uma grande amplitude de padrões de abundância relativa e é de utilização relativamente simples, podendo ser utilizado em testes experimentais de perturbação ou de sucessão ecológica. Aliado a medidas independentes de dimensões de nicho, este modelo pode ainda oferecer respostas sobre quais recursos são essenciais à estruturação de comunidades biológicas.
Assuntos
Animais , Humanos , Biodiversidade , Modelos Biológicos , Especificidade da Espécie , Migração Animal , Brasil , Modelos Estatísticos , Distribuição Normal , Densidade Demográfica , Dinâmica PopulacionalRESUMO
The literature on species abundance models is extensive and a great deal of new and important contributions have been published in the last three decades. Broadly speaking, one can recognize five families of species abundance models: i) purely statistical or classic models (Broken-stick, Log-normal, Logarithmic and Geometric series); ii) branching process (Zipf-Mandelbrot and Fractal branching models); iii) population dynamics (Neutral models included); iv) spatial distribution of individuals (Multifractal and HEAP models) and v) niche partitioning (Sugihara's breakage and Tokeshi models). Among these the neutral, the classic and the niche partitioning models have been the most applied to natural communities, the former having been more extensively discussed than the others in the last years. The objective of this paper is to comment some aspects of the classic, neutral and niche partitioning models in a way that the proposed distributions may contribute to the analysis of the empirical patterns of species abundance. In spite of the variety of models, the distributions in general vary between the log-normal and the logarithmic series. From these models the Power-Fraction, together with independent niche dimensions measures, are amenable to experimental tests and may offer answers on which resources are important in the structuring of biological communities.
Assuntos
Biodiversidade , Modelos Biológicos , Especificidade da Espécie , Migração Animal , Animais , Brasil , Humanos , Modelos Estatísticos , Distribuição Normal , Densidade Demográfica , Dinâmica PopulacionalRESUMO
The effect of anthropic alterations such as drain discharge on a fish community was studied in the Ribeirão Claro River, municipality of Rio Claro, State of São Paulo, southeastern Brazil. Samples were made monthly in three different points along the river (headwaters, mid course, and confluence) between December, 2003 and March, 2004, which is the reproductive period for the majority of the species. The fish community of the Ribeirão Claro River showed a fair composition and diversity, with species rarely observed in studies made in the region, such as Paravandellia oxyfera and Callichthys callichthys. Indices of diversity and equitability showed different results when weight or the number of individuals were considered. Moreover, these indices did not reveal the typical increase in diversity from the headwaters toward the confluence, nor the loss of richness in the part altered by drain discharge. An interpretation should be made with caution, taking into account the diverse factors included in the computation. Similar to the diversity indices, the Morisita-Horn similarity index did not reveal a great difference in the fish community of the confluence of the river, mainly in relation to its mid course. The decline of species richness and trophic composition alteration in the disturbed part is clear, which shows a great dominance of piscivorous species.
Assuntos
Biodiversidade , Monitoramento Ambiental , Peixes/classificação , Rios/química , Esgotos/efeitos adversos , Animais , Brasil , Peixes/fisiologia , Densidade DemográficaRESUMO
The effect of anthropic alterations such as drain discharge on a fish community was studied in the Ribeirão Claro River, municipality of Rio Claro, State of São Paulo, southeastern Brazil. Samples were made monthly in three different points along the river (headwaters, mid course, and confluence) between December, 2003 and March, 2004, which is the reproductive period for the majority of the species. The fish community of the Ribeirão Claro River showed a fair composition and diversity, with species rarely observed in studies made in the region, such as Paravandellia oxyfera and Callichthys callichthys. Indices of diversity and equitability showed different results when weight or the number of individuals were considered. Moreover, these indices did not reveal the typical increase in diversity from the headwaters toward the confluence, nor the loss of richness in the part altered by drain discharge. An interpretation should be made with caution, taking into account the diverse factors included in the computation. Similar to the diversity indices, the Morisita-Horn similarity index did not reveal a great difference in the fish community of the confluence of the river, mainly in relation to its mid course. The decline of species richness and trophic composition alteration in the disturbed part is clear, which shows a great dominance of piscivorous species.
Com o objetivo de verificar o efeito de alterações antrópicas, como o despejo de esgotos sobre a comunidade de peixes do Ribeirão Claro, SP, foram feitas coletas mensais em três pontos ao longo do rio (cabeceira, meio e foz) entre dezembro de 2003 e março de 2004, período reprodutivo para a maioria das espécies da região. O Ribeirão Claro apresentou boa composição e variedade em sua comunidade íctia, possuindo espécies raramente observadas em trabalhos na região, como Paravandellia oxyfera e Callichthys callichthys. Os índices de diversidade e equitabilidade apresentaram diferentes resultados quando considerado o peso ou número de indivíduos, além de não evidenciarem o comportamento típico de aumento da diversidade no sentido cabeceira-foz, nem a conseqüente perda de riqueza taxonômica no trecho impactado pelo despejo de esgoto doméstico. Sua interpretação deve ser feita com cautela, considerando os diversos aspectos incluídos em seus cálculos. Assim como os índices de diversidade, a similaridade de Morisita-Horn não ressaltou a grande diferença na comunidade da foz do Ribeirão Claro, em especial com relação ao trecho médio do rio. Fica evidente o declínio na riqueza de espécies no trecho poluído e a alteração em sua composição trófica, apresentando alta dominância de espécies piscívoras.
Assuntos
Animais , Biodiversidade , Monitoramento Ambiental , Peixes/classificação , Rios/química , Esgotos/efeitos adversos , Brasil , Peixes/fisiologia , Densidade DemográficaRESUMO
Atomic force microscopy (AFM) was used to study the nanoscale surface chemistry and morphological changes caused by chemical treatment of sisal fibers. Scanning Electron Microscopy (SEM) micrographs indicated that sisal in natura (bundle of fibers) is formed by fibers with diameters of approximately 10 microm. AFM images showed that these fibers consist of microfibrils with diameters varying from 250 to 600 nm, which are made up of nanofibrils of ca. 20 nm in diameter. The adhesion force (pull-off force) between the AFM tip and the fibers surface increased after benzylation, pointing to a decrease in the polar groups on the sisal fiber. The adhesion map measured over a scan range of 3 microm was heterogeneous in samples treated with 40% NaOH and the low adhesion sites disappeared after benzylation. Using an established mathematical model, it was possible to evaluate the increase in adhesion work and consequently in the interaction between the AFM tip and sisal fibers. These results indicated that AFM can detect heterogeneity in the wettability of sisal fibers with nanometer resolution and can be applied in the study of fiber-matrix adhesion in polymer composites.
Assuntos
Agave/química , Microscopia de Força Atômica/métodos , Nanotecnologia/métodos , Adesivos , Biofísica/métodos , Adesão Celular , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Modelos Estatísticos , Nanoestruturas/química , Propriedades de Superfície , Aderências TeciduaisRESUMO
The optimised geometries of heterocyclic hydrogen-bonded complexes, C2H4O...HX and C3H6O...HX, where X=F or Cl, were determined at DFT/B3LYP/6-311++G(d,p) computational level. Structural, electronic and vibrational properties of these complexes are used in order to compare the strained ring, which confer the great reactivity of these heterocyclic rings with monoprotic acids, forming a primary hydrogen bond. A secondary hydrogen bond between the hydrogen atoms of the CH2 groups and the halide species also takes place, thus causing a nonlinearity (characterized by the theta angle), in the primary hydrogen bond.
Assuntos
Compostos Heterocíclicos/química , Ácido Clorídrico/química , Ácido Fluorídrico/química , Éteres Cíclicos/química , Óxido de Etileno/química , Ligação de Hidrogênio , Modelos Químicos , Conformação MolecularRESUMO
Os laxativos disponíveis no mercado brasileiro são enquadrados pela legislação em vigor na categoria de Venda Sem Prescrição Médica. Os consumidores, consequentemente, realizam automedicação de laxativos, sem considerarem as diferenças no diagnóstico da constipação e a segurança dos laxativos. Avaliar o enquadramento dos laxativos na categoria de Venda Sem Prescrição Médica, mediante revisão bibliográfica sobre constipação e segurança dos laxativos, considerando as especialidades farmacêuticas existentes no Brasil em 2003. Levantamento das especialidades farmacêuticas laxativas existentes no Brasil em 2003, através de publicações específicas. Revisão bibliográfica sobre constipação, segurança dos laxativos e categoria de venda dos medicamentos, através da Internet e livros da farmacologia. Em 2003 estão disponíveis 61 especialidades farmacêuticas laxativas no Brasil, todas enquadradas nas categorias de "Venda Sem Prescrição Médica". O tratamento ideal da constipação depende do entendimento da fisiopatologia desta condição. Foram encontrados dados controversos sobre a associação entre o uso de laxativos estimulantes e câncer colorretal ou disfunção neuromotora do intestino. Os dados controversos são preocupantes diante do número elevado de laxativos encontrados no mercado, além de serem considerados pela legislação atual, que enquadra todos os laxantes na categoria de Venda Sem Prescrição Médica, independentemente do modo de ação
Assuntos
Catárticos/efeitos adversos , Catárticos/farmacologia , Catárticos/normas , Medicamentos sem Prescrição/efeitos adversos , Medicamentos sem Prescrição/normas , Automedicação/efeitos adversos , Constipação Intestinal , Neoplasias Colorretais/complicaçõesRESUMO
During 1985-1995, illnesses clinically and epidemiologically compatible with Brazilian spotted fever were identified in 17 patients in the county of Pedreira, in the state of São Paulo, Brazil. Spotted-fever group rickettsial infection was confirmed by serology and/or immunostaining of tissues in 10 of these patients. Immunostaining confirmed infection in a 37-year-old pregnant patient, although rickettsial antigens were not demonstrable in the tissues of the fetus. A serosurvey was conducted in four localities in the county to determine the prevalence of subclinical or asymptomatic infections with spotted fever group rickettsiae. Five hundred and twenty-five blood samples were tested by an indirect immunofluorescence assay for antibodies reactive with Rickettsia rickettsii. Twenty-two (4.2%) of these samples demonstrated titers > or = 1:64. The results indicate that Brazilian spotted fever is endemic within this region of Brazil.
Assuntos
Anticorpos Antibacterianos/sangue , Doenças Endêmicas/estatística & dados numéricos , Rickettsia rickettsii/isolamento & purificação , Febre Maculosa das Montanhas Rochosas/epidemiologia , Adulto , Animais , Brasil/epidemiologia , Criança , Pré-Escolar , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Rickettsia rickettsii/imunologia , Febre Maculosa das Montanhas Rochosas/imunologia , Febre Maculosa das Montanhas Rochosas/microbiologia , Estudos Soroepidemiológicos , Testes Sorológicos , Pele/patologiaRESUMO
Foram estudadas as alteraçöes oxidativas de 250 amostras de hambúrguer de carne bovina de mesma data de produçäo e de mesma partida. As amostras foram divididas em três grupos e submetidas a estocagem em temperaturas de -1§C, -8§C e -18§C. As amostras de cada grupo foram submetidas periodicamente à análises qualitativa (prova de Kreiss), e provas quantitativas (Número de TBA e Indice de Peróxido) para avaliaçäo do desenvolvimento da oxidaçäo lipídica. Os resultados mostram que o ranço pronunciado foi detectado após 15 dias de conservaçäo a temperatura de -1§C, após 30 dias à -8§C e após 90 dias à -18§C. A análise dos resultados evidenciou que a vida de prateleira do hambúrguer testado foi influenciada significativamente (P<0,01) pelo aumento de temperatura. Observou-se assim uma correlaçäo inversa entre temperatura e tempo de estocagem do hambúrguer. Conclui-se assim que as amostras estocadas em temperturas mais elevadas (-1§C e -8§C) apresentam alta sensibilidade ao desenvolvimento da rancidez e que os hambúrgueres estocados à temperatura de -18§C poderiam ser conservados por 90 dias.