Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 192 )

2018 ( 447 )

2017 ( 456 )

2016 ( 511 )

Custom range...

Search Results: 1 - 10 of 267744 matches for " José L. Mazzei "
All listed articles are free for downloading (OA Articles)
Page 1 /267744
Display every page Item
Preliminary Study by Environmental Indicator Measurements of Sediments in a Mangrove Forest in Ilha Grande Bay, Rio de Janeiro, Southeastern Brazil  [PDF]
Ana Maria A. Velho, Claudia A. F. Aiub, José L. Mazzei, Sérgio M. Corrêa, Mário L.G. Soares, Israel Felzenszwalb
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.38087
Abstract: Mangroves perform essential functions in biological cycles and are protected by law in Brazil. However, they are being degraded above their support limit, leading to a reduction in the areas around the world. The area investigated in the present study is a potentially unpolluted mangrove ecosystem in the south of Rio de Janeiro state, Brazil. The aim of this work was to investigate the presence of metals and polycyclic aromatic hydrocarbons (PAHs) in mangrove sediment and to correlate them with mutagenic and genotoxic activity. Four seasonal samplings undertaken between 2009 and 2010 at five sites were analyzed. Dichloromethane extracts were obtained under sonication and subjected to mutagenicity assays using Salmonella microsuspension. Metal (Cd, Cr, Cu, Ni and Pb) contents were determined by atomic absorption spectrometry, while the quantification of PAHs was performed by gas chromatography-mass spectrometry. Goniopsis cruentata hemocytes were used to assess potential genotoxic damage (Micronucleus assay). The absence of mutagenicity was observed for all samples using Salmonella typhimurium strains TA97, TA98, TA100 and TA102, in the absence and presence of an exogenous mammalian metabolizing system. Among the metals, Cd and Cu were detected in autumn at values exceeding the threshold effect level and below the probable effect level. Benzo[a] pyrene was detected at levels above the threshold at one site, where small effects could be observed in the biota. Significant differences in the micronucleated cells observed suggest DNA damage had been induced by the PAHs identified.
Separation of Acylglycerols from Biodiesel by High Performance Liquid Chromatography and Solid-Phase Extraction [ Separa o dos Acilgliceróis do Biodiesel por Cromatografia Líquida de Alta Eficiência e Extra o em Fase Sólida]
Débora F. de Andrade,José L. Mazzei,Luiz A. d’Avila
Revista Virtual de Química , 2011,
Abstract: In this study an alternative method was developed using a non-aqueous reversed phase high performance liquid chromatography (NARP-HPLC) to determine conversion and characterize the principal components of B100 biodiesel obtained from vegetable oils at several conversion rates. A novel solid-phase extraction (SPE) method with aminopropylsilane cartridges was proposed to enrich and separate the acylglycerols (mono-, di- and triacylglycerols) from B100 biodiesel. Soybean, corn, sunflower, cottonseed and canola oils were transesterified with methanol under reflux to different conditions, yielding 35 products which were submitted to investigation. The NARP-HPLC method was able to separate the fatty acid methyl esters (FAME) and the different classes of acylglycerols, making it an alternative for monitoring the conversion of different vegetable oils. In SPE, FAME elute selectively with n-hexane (reaching up to 100% recovery), whereas a fraction enriched (three- to six-fold) with the acylglycerols, elute subsequently with chloroform/methanol 2:1. The separation of the fractions of EsMAG and acylglycerols should contribute to the chemical characterization of the B100 for several analytical techniques. The combination of NARP-HPLC and SPE could be a new starting point for monitoring the quality of biodiesel, for the isolation of acylglycerols and for the production of reference materials.
Desenvolvimento e aplica??o de metodologia por cromatografia em camada delgada para determina??o do perfil de alcalóides oxindólicos pentacíclicos nas espécies sul-americanas do gênero Uncaria
Valente, Ligia M.M.;Alves, Flaviane F.;Bezerra, Giselle M.;Almeida, Maria Beatriz S.;Rosario, Sandra L.;Mazzei, José L.;d'Avila, Luiz A.;Siani, Antonio C.;
Revista Brasileira de Farmacognosia , 2006, DOI: 10.1590/S0102-695X2006000200015
Abstract: the species uncaria tomentosa (willd.) dc. and u. guianensis gmel. (rubiaceae), known as cat's claw, are large woody vines occurring in the amazon rain forest and other tropical areas of south and central america. it has been used medicinally by indigenous peoples for at least 2,000 years for several diseases. tetra- and pentacyclic oxindole alkaloids, triterpenoid glycosides, sterols and flavonoids are found in these plants. among these metabolites, six pentacyclic oxindole alkaloids, speciophylline, mitraphylline, pteropodine, uncarine f, isopteropodine and isomitraphylline, are considered to be the biochemical markers and are used to standardize commercial herbal medicines. the present study describes the development of an analytical methodology to determine the profile of these alkaloid markers through thin layer chromatography (tlc). this development has also included a comparison among the use of the crude methanol extract and fractions obtained through the classical acid-base partition or by using the basic resin polyamide 6. silica gel was used as stationary phase with the variation of some parameters such as solvent systems, sample concentration, distance of development and detection method. the tlc method developed was shown to be reliable, reproducible and selective for the target alkaloids. it has been applied to the analysis of leaves and stems from both species as well as phytopharmaceutical derivatives based on u. tomentosa.
Análise química quantitativa para a padroniza??o do óleo de copaíba por cromatografia em fase gasosa de alta resolu??o
Tappin, Marcelo R. R.;Pereira, Jislaine F. G.;Lima, Lucilene A.;Siani, Antonio C.;Mazzei, José L.;Ramos, M?nica F. S.;
Química Nova , 2004, DOI: 10.1590/S0100-40422004000200012
Abstract: quantitative gc-fid was evaluated for analysis of methylated copaiba oils, using trans-(-)-caryophyllene or methyl copalate as external standards. analytical curves showed good linearity and reproducibility in terms of correlation coefficients (0.9992 and 0.996, respectively) and relative standard deviation (< 3%). quantification of sesquiterpenes and diterpenic acids were performed with each standard, separately. when compared with the integrator response normalization, the standardization was statistically similar for the case of methyl copalate, but the response of trans-(-)-caryophyllene was statistically (p < 0.05) different. this method showed to be suitable for classification and quality control of commercial samples of the oils.
As rela??es de trabalho em uma empresa global: um novo paradigma ou neocorporativismo?
Nogueira, Arnaldo José Fran?a Mazzei;
Caderno CRH , 2009, DOI: 10.1590/S0103-49792009000300011
Abstract: this paper discusses labor relationships in a global company and it was the result of research in an trucks assembly plant in the abc area in the state of s?o paulo, brazil. the company studied presents a most advanced pattern in the organizational dimension in labor relationships or in the workplace, brazilian context considered. the solution of labor conflicts in this company points strongly to a negociation pattern in relation to the statutory (zylberstajn and pastore 1985), what took some authors to indicate a way of cooperation-conflictive to work with labor relationships (rodrigues 1997) and an institutionalized way of workers insertion in the processes of technological and managerial innovation (bresciani 2002). the scheme mounted in the company was a result of the union strategy in the workplace and of the company administration, in particular of human resources. the analysis of the experience allowed to verify, besides an advanced paradigm of labor relationships, the statement of a tendency to the societary corporativism or neo-corporativism in relation to the corporativism typical of state companies in the brazilian labor system.
Labor relations in nonprofit organizations Uma reflex o sobre as rela es de trabalho em organiza es sem fins lucrativos
Arnaldo José Fran?a Mazzei Nogueira,Viviane de Barros Rossini
Rege : Revista de Gest?o , 2007,
Abstract: Development of labor relations in nonprofit organizations and current world practice in general were reviewed in literature. Examples of these organizations and their work characteristics were compared with labor relations in the public, the private and third sector. The increasing sophistication of these organizations, with a growing number of paid employees, raises questions related to the analysis of employee and organization dynamics and interactions which differ from those of the other sectors. As such, this study intended to launch considerations about how to conduct an analysis of this different sector as well as to evaluate the contribution of the more conventional experience available. O presente trabalho pretende, por meio de levantamento bibliográfico, analisar as características das rela es de trabalho nas organiza es sem fins lucrativos e verificar como elas vêm sendo construídas a partir dos elementos responsáveis pelo crescimento relevante do setor e pelas rela es de trabalho em todos os setores no mundo atual. Para tanto, ser o utilizados números representativos dessas organiza es e características dos mesmos na área do trabalho, além de uma discuss o comparativa das rela es do trabalho nos setores público, privado e no terceiro setor. A crescente utiliza o de trabalhadores assalariados no setor, em conseqüência de seu desenvolvimento e maior complexidade, levanta a quest o tanto da dinamica das intera es entre esses trabalhadores e essas organiza es quanto da maneira pela qual essa dinamica deverá ser analisada, uma vez que apresenta características distintas dos setores estatal e privado. Assim, o estudo procura iniciar uma reflex o sobre como realizar essa análise, ao mesmo tempo em que avalia se as rela es atuais de trabalho podem, através de seus conceitos, fornecer indica es sobre as intera es neste setor particular.
G. DeZotti,A. Franceschini,P. Mazzei,L. Granato,L. Danese
Physics , 1995,
Abstract: Infrared surveys provide essential insights on galaxy evolution. If near-IR studies suggest mild evolution of stellar populations with cosmic time, indications of a substantial evolution have been seen in the far-IR, although the available information is largely insufficient to delineate precise evolutionary properties. A consistent picture encompassing all the currently available data may be obtained assuming that dust extinction hides the early evolutionary phases of spheroidal galaxies in the optical band, while the corresponding dust re-radiation in the far-IR may have been, during the early evolutionary phases, orders of magnitude larger than today. Hyperluminous IRAS galaxies might be extreme examples of this situation. Additional indications that at least some spheroidal galaxies may have been very dusty during their early evolution are provided by recent data on high redshift radio galaxies and quasars. Galaxies are the likely dominant contributors to the IR background. However, in the framework of unified models for Active Galactic Nuclei, a large number of nuclei hidden by a dusty torus may be expected. Implications for the IR background are discussed.
In vitro cultivated Uncaria tomentosa and Uncaria guianensis with determination of the pentacyclic oxindole alkaloid contents and profiles
Pereira, Rita de C. A.;Valente, Ligia M. M.;Pinto, José E. B. P.;Bertolucci, Suzan K. V.;Bezerra, Giselle M.;Alves, Flaviane F.;Santos, Priscila F. P. dos;Benevides, Paulo J. C.;Siani, Ant?nio C.;Rosario, Sandra L.;Mazzei, José L.;d'Avila, Luiz A.;Gomes, Luiz N. F.;Aquino-Neto, Francisco R. de;Emmerick, Isabel C. M.;Carvalhaes, Sergio F.;
Journal of the Brazilian Chemical Society , 2008, DOI: 10.1590/S0103-50532008000600021
Abstract: uncaria tomentosa (willd.) dc. and uncaria guianensis (aubl.) gmel., commercially known as cat's claw, are large woody vines native of the amazon and central america rainforests. these rubiaceae species face nowadays an imminent risk of extinction due to indiscriminate harvesting in the wild as well as to increasing deforestation of their natural habitat. this work describes in vitro cultivation methods for both species with determination, by hplc, of the pentacyclic oxindole alkaloid contents and profiles of the plant material. the results have proved that the methods we developed were able to produce plants with alkaloid profiles and contents similar to the wild and in vivo cultivated species, and with the additional advantage of producing suitable young plants in a shorter period of time. the data showed that the in vitro technique can be a feasible tool for the growth of the species, and may thus be important for their commercialization and for their conservation as a forest resource.
Frecuencia e incidencia de la tromboembolia venosa en un hospital general
Mazzei,Juan A.; Campos,Ana L.; Melero,Marcelo J.;
Medicina (Buenos Aires) , 2005,
Abstract: the objective of this study was to determine the frequency and incidence of venous thromboembolism (vte) in an argentine universitary hospital. we used a longitudinal, retrospective, observational design. participants were all over-16 year patients who were discharged or died in clinical, obstetrical and surgical units in the hospital de clínicas josé de san martín during a 24 month period between july 1, 2001 and june 30, 2003, with a diagnosis on release of vte. vte frequency reached 0.92% and incidence was 0.40%; 95% confidence interval (95% ci): 0.37 to 0.42%. incidence was highest in the 9th decade of life (0.80%; 95% ci: 0.78% to 0.82%). only 31% of patients who developed vte during hospitalization had received thromboprophylaxis. total in-hospital mortality of vte patients was 19%.
Tromboprofilaxis en pacientes no quirúrgicos internados en un hospital general
Melero,Marcelo J.; Pagotto,Vanina L.; Mazzei,Juan A.;
Medicina (Buenos Aires) , 2012,
Abstract: adult patients hospitalized for a non-surgical condition, usually have a high risk of venous thromboembolism and may develop some form of this disease when they do not receive appropriate preventive treatment. the objectives of this prospective, analytical, observational and cross-sectional study were: 1) to determine what percentage of adult patients hospitalized for a non-surgical acute condition at the hospital de clínicas josé de san martín, universidad de buenos aires, had indication for preventive thromboprophylaxis, 2) to establish how many of them had been prescribed a preventive treatment of venous thromboembolism, 3) to establish how many of them had been prescribed a preventive treatment of venous thromboembolism without having reasons to justify the treatment. the study was performed on 93 patients for 72 consecutive hours. it resulted in 90.3% in need of preventive treatment for venous thromboembolism and 76.2% of these patients had received pharmacological thromboprophylaxis. a 33.3% of the studied patients had received preventive pharmacological treatment without having a proper indication. in this study, the percentage of patients treated is higher than in those reported in other published observational studies.
Page 1 /267744
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.