616 research outputs found

    Temperature measurements by oh lif and chemiluminescence kinetic modeling for ethanol flames

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    OH LIF-thermometry was applied to premixed ethanol flames at atmospheric pressure in a burner for three flame conditions. Flame temperatures were simulated from energy equation with PREMIX code of CHEMKIN software package for comparison. A kinetic modeling based on a model validated through chemiluminescence measurements and on a set of reactions for nitrogen chemistry was evaluated. Marinov's mechanism was also tested. Sensitivity analysis was performed for fuel-rich flame condition with Φ = 1.34. Simulated temperatures from both reaction mechanisms evaluated were higher than experimental values. However, the proposed kinetic modeling resulted in temperature profiles qualitatively very close to the experimental

    Membrane transport systems and the biodegradation potential and pathogenicity of genus Rhodococcus

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    PMID:24772091 WOS:000347032600001The Rhodococcus genus contains species with remarkable ability to tolerate toxic compounds and to degrade a myriad of substrates. These substrates have to cross a distinctive cell envelope dominated by mycolic acids anchored in a scaffold of arabinogalactan covalently attached to the cell wall peptidoglycan, and a cellular membrane with phospholipids, whose composition in fatty acids can be rapidly altered in response to environmental conditions. The hydrophobic nature of the cell envelope facilitates the entrance of hydrophobic molecules but some substrates require active transport systems. Additionally, toxic compounds may also be extruded by energy spending efflux systems. In this review, physiological evidences of the use of transport systems by Rhodococcus strains and genomic studies that corroborate their existence are presented and discussed. The recently released complete genomes of several Rhodococcus strains will be the basis for an in silico correlation analysis between the efflux pumps present in the genome and their role on active transport of substrates. These transport systems will be placed on an integrative perspective of the impact of this important genus on biotechnology and health, ranging from bioremediation to antibiotic and biocide resistance.publishersversionpublishe

    Toll-like receptor 4 expression in the epithelium of inflammatory periapical lesions. An immunohistochemical study

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    Toll-like receptors (TLR) are essential for the innate immune response against invading pathogens and have been described in immunocompetent cells of areas affected by periapical disease. Besides initiating the inflammatory response, they also directly regulate epithelial cell proliferation and survival in a variety of settings. This study evaluates the in situ expression of TLR4 in periapical granulomas (PG) and radicular cysts, focusing on the epithelial compartment. Twenty-one periapical cysts (PC) and 10 PG were analyzed; 7 dentigerous non-inflamed follicular cyst (DC) served as control. TLR4 expression was assessed by immunohistochemistry. TLR4 immunoreaction products were detected in the epithelium of all specimens, with a higher percentage of immunostained cells in PG. Although TLR4 overexpression was detected in both PG and PC, there were differences that seemed to be related to the nature of the lesion, since in PG all epithelial cells of strands, islands and trabeculae were strongly immunoreactive for TLR4, whereas in PC only some areas of the basal and suprabasal epithelial layers were immunostained. This staining pattern is consistent with the action of TLR4: in PG it could promote formation of epithelial cell rests of Malassez and in epithelial strands and islands the enhancement of cell survival, proliferation and migration, whereas in PC TLR4 could protect the lining epithelium from extensive apoptosis. These findings go some way towards answering the intriguing question of why many epithelial strands or islands in PG and the lining epithelium of apical cysts regress after non-surgical endodontic therapy, and suggest that TLR4 plays a key role in the pathobiology of the inflammatory process related to periapical disease

    Snake Venom: Any Clue for Antibiotics and CAM?

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    Lately several naturally occurring peptides presenting antimicrobial activity have been described in the literature. However, snake venoms, which are an enormous source of peptides, have not been fully explored for searching such molecules. The aim of this work is to review the basis of antimicrobial mechanisms revealing snake venom as a feasible source for searching an antibiotic prototype. Therefore, it includes (i) a description of the constituents of the snake venoms involved in their main biological effects during the envenomation process; (ii) examples of snake venom molecules of commercial use; (iii) mechanisms of action of known antibiotics; and (iv) how the microorganisms can be resistant to antibiotics. This review also shows that snake venoms are not totally unexplored sources for antibiotics and complementary and alternative medicine (CAM)

    Phenotyping the ideotypes of two maize landraces from Madeira archipelago using morpho-agronomic traits and zein pattern

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    Madeira Archipelago holds specific maize genetic resources whose populations, representing field diversity, were previously classified into four main landrace groups. The ISOPs 0061 and 0070, with common names of “Milho Sequeiro” and “Milho Branco” yellow and white maize, respectively, represent the ideotypes of two of these landraces. These ideotypes have now been analyzed using morpho-agronomic and biochemical traits, to phenotype these landraces. The variation of nine of the ten morpho-agronomic traits was used to separate the landraces ideotypes. However, the seven traits of seed biochemical composition did not allow to segregate the landraces ideotypes. This is not the case of zein pattern, which polymorphism shows to be specific for each ideotype. The original ideotypes populations were regenerated twice under low input conditions. Zein patterns of the original and regenerated accessions were compared, using two electrophoresis techniques. The lab-on-a-chip electrophoresis showed that the standard SDS-PAGE zein pattern with six fractions could be separated into eighteen (ISOP 0061) and twenty (ISOP 0070) protein bands. In contrast, no significant changes were detected in the zein pattern structure of the initial and regenerated accessions of both landraces ideotypes. The chip electrophoresis showed to be a suitable technique to screen and characterize a large number of individuals and accessions of the germplasm collections, due to its reproducibility. In particular, the zein patterns can be used to phenotype ideotypes and establish a formula representing their structure, allowing to detect changes in landrace structure, occurring as a result of gene bank management actions.info:eu-repo/semantics/publishedVersio

    Classificação de resíduos de madeira tratada com preservativos à base de arseniato de cobre cromatado e de boro/flúor

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    Classification of waste wood treated with chromated copper arsenate (CCA) and boron/fluorine preservatives, according to NBR 10004, was investigated. The leaching test (ABNT NBR 10005) for As and Cr, and solubilization test (ABNT NBR 10006) for F, were applied to out-of-service wooden poles. Concentrations of As and Cr in leachates were determined by ICP-MS and of F by ESI. Values for As were higher than 1 mg L-1 classifying the waste as hazardous material (Class I) whereas values for F (> 1.5 mg L-1) were non-hazardous but indicated non-inert material (Class IIA)

    Evidences of herbal medicine-derived natural products effects in inflammatory lung diseases

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    Pulmonary inflammation is a hallmark of many respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), and acute respiratory syndrome distress (ARDS). Most of these diseases are treated with anti-inflammatory therapy in order to prevent or to reduce the pulmonary inflammation. Herbal medicine-derived natural products have been used in folk medicine and scientific studies to evaluate the value of these compounds have grown in recent years. Many substances derived from plants have the biological effects in vitro and in vivo, such as flavonoids, alkaloids, and terpenoids. Among the biological activities of natural products derived from plants can be pointed out the anti-inflammatory, antiviral, antiplatelet, antitumor anti-allergic activities, and antioxidant. Although many reports have evaluated the effects of these compounds in experimental models, studies evaluating clinical trials are scarce in the literature. This review aims to emphasize the effects of these different natural products in pulmonary diseases in experimental models and in humans and pointing out some possible mechanisms of action.CNPq [300546/2012-2, 304465/2012-7, 476877/2012-1]FAPESP [2010/14831-3, 2011/15817-7, 2008/55359-5]Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Federal University of São Paulo, Diadema-SP 09972-270, BrazilSchool of Medicine, University of São Paulo, São Paulo-SP 01246903, BrazilInstituto de Saúde e Sociedade, Federal University of São Paulo, Santos-SP 11015-020, BrazilInstituto de Ciências Ambientais, Químicas e Farmacêuticas, Federal University of São Paulo, Diadema-SP 09972-270, BrazilInstituto de Saúde e Sociedade, Federal University of São Paulo, Santos-SP 11015-020, BrazilCNPq: 300546/2012-2CNPq: 304465/2012-7CNPq: 476877/2012-1FAPESP: 2010/14831-3FAPESP: 2011/15817-7FAPESP: 2008/55359-5Web of Scienc
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