999 resultados para Palestrantes Principais
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OBJETIVO: Descrever os principais achados de imagem em uma série de casos de tumores neuroendócrinos primários do pulmão (TNPs), destacando as alterações na tomografia computadorizada. MATERIAIS E MÉTODOS: Exames de 22 pacientes (12 homens, idade média de 60 anos) avaliados nos últimos cinco anos em nosso serviço, com confirmação histopatológica, foram retrospectivamente revistos por dois médicos radiologistas e os achados foram descritos em consenso, focando as alterações tomográficas. RESULTADOS: Descrevemos 5 carcinoides típicos, 3 carcinoides atípicos, 3 carcinomas neuroendócrinos de grandes células (CNGCs) e 11 cânceres pulmonares de pequenas células (CPPCs). Apenas um carcinoide típico apresentou aspecto característico de nódulo endobrônquico central com atelectasia pulmonar distal, enquanto os demais foram nódulos ou massas pulmonares. Os carcinoides atípicos eram massas pulmonares periféricas e heterogêneas. Um CNGC era massa periférica delimitada e homogênea, enquanto os demais eram mal delimitados e heterogêneos. Os 11 CPPCs eram massas centrais, infiltrativas e heterogêneas, com alterações pleuropulmonares secundárias. Calcificações estavam ausentes nos CNGCs e CPPCs. Metástases foram vistas inicialmente ou no seguimento de todos os CNGCs e CPPCs. CONCLUSÃO: Apesar de alguns aspectos semelhantes nos exames de imagem, os achados radiológicos, quando integrados às informações clínicas, podem constituir critérios importantes na diferenciação dos tipos histológicos de TNPs.
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Hexafluoroacetylaceton derivatives of some synthesized components of the guazatine fungicide were prepared, and their separation and identification performed through gas chromatography and gas chromatography-mass spectrometry. The chromatogram obtained from hexafluoroacetylacetone derivative of the commercial guazatine presented 14 major peaks, and 9 of them were identified through both techniques mentioned above.
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Six Brazilian commercial mangoes were analysed by HRGC-O-AEDA-MS, viz., Carlota, Haden, Espada, Coração de boi, Rubi and Tommy Atkins. All them showed ethyl butanoate as the main aroma character impact compound by AEDA evaluation. The ethyl esters of 2 and 3-methylbutanoic acids are also important, the main contribution in Carlota variety being 2(S) enantiomer. In Rubi variety, both 2(R) enantiomer and 3-methyl isomer contributes to the caprylic fruity note observed. In four varieties, viz., Haden, Espada, Rubi and Tommy Atkins, d-3-carene showed to be the second impact aroma compound presented. In Tommy Atkins variety, a-pinene also has a significant contribution, mainly due to its (1R,5R)(+)-enantiomer.
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This work describes the more promising chemical and pharmacological or biological results obtained with some selected Brazilian medicinal plants, which has been conducted at Núcleo de Investigações Químico-Farmacêuticas (NIQFAR)/UNIVALI in the last five years. It was found that several phytoconstituents exhibit different activities, such as antispasmodic, antiallergic, analgesic, antiinflammatory, antimicrobial and antiviral. Some of them were more potent than some well-known standard drugs used clinically.
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This paper reviews the most important methods used to characterize the porosity of styrene-divinylbenzene resins. Methods such as adsorption of nitrogen for determination of surface area and mercury intrusion porosimetry for characterization of pore size distribution are related.
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This paper provides a review on voltammetric and polarographic methods for the speciation analysis of inorganic and organic arsenic compounds in different matrices. A discussion on the main advantages of electroanalytical methods in comparison with other analytical methods employed for arsenic speciation is presented. The mechanistic aspects of the most relevant techniques employing cathodic and anodic stripping voltammetry as well as polarographic methods published in the last twenty five years are summarized and discussed. The bibliographic references cited in this work were selected from the Web of Science (published by the ISI) and the main journals of analytical chemistry.
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The cucurbitacins are highly oxygenated triterpenoid compounds found in several botanical families that show high toxicity and varied biological activities. This review presents the main cucurbitacins so far isolated and their key structural characteristics. It complements and updates the existing reviews on this subject.
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In this work a closed-vessel microwave-assisted acid decomposition procedure for clays was developed. Aluminum, Ca, Fe, K, Mg, Na, Si, and Ti were determined in clay digestates by inductively coupled plasma optical emission spectrometry. The most critical parameter for total decomposition of clays was the composition of the reagent mixture. The applied power and the heating time exerted a less critical influence. Best decomposition conditions were attained using a reagent mixture containing 4 mL aqua regia plus 3 mL HF and the heating program was implemented in 12 min. The accuracy of the results was demonstrated using two standard reference materials and a paired t-test showed a good agreement between determined and certified values at a 95% confidence level.
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The ¹H NMR data set of a series of 3-aryl (1,2,4)-oxadiazol-5-carbohydrazide benzylidene derivatives synthesized in our group was analyzed using the chemometric technique of principal component analysis (PCA). Using the original ¹H NMR data PCA allowed identifying some misassignments of the proton aromatic chemical shifts. As a consequence of this multivariate analysis, nuclear Overhauser difference experiments were performed to investigate the ambiguity of other assignments of the ortho and meta aromatic hydrogens for the compound with the bromine substituent. The effect of the 1,2,4-oxadiazol group as an electron acceptor, mainly for the hydrogens 12,13, has been highlighted.
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The amidine functional group is found in a wide range of natural products and is biologically active against several pathogens. In addition, amidines have long been regarded as useful intermediates in the synthesis of heterocyclic compounds. Consequently, a great number of methods have been developed for the preparation of amidines. Pinner's method is the most commonly used. Conventional methods include: - the addition of metal amides or amines to nitriles, the addition of amines to imido esters and the condensation of amides with amines in the presence of halogenating reagents. In this report, the main methods for synthesis of amidines will be described.
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There is considerable progress in the study of the biotransformation of limonene. Extensive research on the biotransformation of limonene has resulted in the elucidation of new metabolic pathways. Natural flavors can be produced via biotransformation, satisfying consumer demand for natural products. This review presents some elements concerning the biotransformation of limonene with emphasis on the metabolic pathways. Some comments are also made on problems related to biocatalysis as well as on the application of some compounds originating from the biotransformation of the inexpensive limonene.
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Residues of herbicides from sugarcane were monitored in waters and sediments of Corumbataí River and tributaries. Ametryne, atrazine, simazine, hexazinone, glyphosate, and clomazone were detected in water samples, with negligible levels of ametryne and glyphosate in sediment samples. The area of recharge of the Guarani aquifer presented the highest triazine and clomazone levels. The triazines were detected at higher levels, with atrazine above Brazil's potability and quality standards. Total herbicide levels at some sampling points were 13 times higher than the European Community potability limit. There is no Brazilian standard for ametryne, although the risk is larger due to ametryne's higher toxicity for the aquatic biota.
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We review here the chemistry of reactive oxygen and nitrogen species, their biological sources and targets; particularly, biomolecules implicated in the redox balance of the human blood, and appraise the analytical methods available for their detection and quantification. Those biomolecules are represented by the enzymatic antioxidant defense machinery, whereas coadjutant reducing protection is provided by several low molecular weight molecules. Biomolecules can be injured by RONS yielding a large repertoire of oxidized products, some of which can be taken as biomarkers of oxidative damage. Their reliable determination is of utmost interest for their potentiality in diagnosis, prevention and treatment of maladies.
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An air quality evaluation of indoor environments with focus on lower carbonyls was carried out in 50 public places using TO-11A methodology. Formaldehyde levels (ranging from 12.5 to 1034 mg m-3) were above the threshold limit in 49 of 50 analyzed samples while acetaldehyde (ranging from 5.2 to 840 mg m-3) and acetone (ranging from 5.5 to 4839 mg m-3) were respectively bellow the limits of OSHA and NIOSH in all samples. However all samples were bellow the threshold limits suggested by the Brazilian legislation - NR-15. A correlation study between the carbonyls and temperature and humidity was also done.
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The spatial and temporal retention of metals has been studied in water and sediments of the Gavião River, Anagé and Tremedal Reservoirs, located in the semi-arid region, Bahia - Brazil, in order to identify trends in the fluxes of metals from the sediments to the water column. The determination of metals was made by ICP OES and ET AAS. The application of statistical methods showed that this aquatic system presents suitable conditions to move Cd2+ and Pb2+ from the water column to the sediment.