A bounded upwinding scheme for computing convection-dominated transport problems

A practical high resolution upwind differencing scheme for the numerical solution of convection-dominated transport problems is presented. The scheme is based on TVD and CBC stability criteria and is implemented in the context of the finite difference methodology. The performance of the scheme is investigated by solving the 1D/2D scalar advection equations, 1D inviscid Burgers’ equation, 1D scalar convection–diffusion equation, 1D/2D compressible Euler’s equations, and 2D incompressible Navier–Stokes equations. The numerical results displayed good agreement with other existing numerical and experimental data

Residual stresses analysis in plasma dressed welded joints

The presence of residual stresses in a structure influences his behaviour. Fatigue strength of welded joints is significantly influenced by the presence of residual stresses, of flaws and notch sharpness at the weld toe. Plasma dressing at the weld toe is frequently used to remove flaws and to lessen the notch sharpness at the weld toe. With this re-melt, the stress field in the weld toe is also profoundly modified. The Finite Element Method (FEM) proves to be effective to simulate the stress fields generated by welding. The simplified two-dimensional models (2D) are efficient in this estimation. This paper presents a 2D finite element model to predict the residual stresses generated by Plasma dressing at the weld toe of a T-joint. The welded T-joints are made in St 52-3 steel, are obtained by covered electrode process and improved with plasma dressing. The analysis was developed with the MSC.Marc finite element code. The estimated stress field is validated with experimental stress results obtained using X-ray diffractio

Triacylglycerol profile as a chemical fingerprint of mushroom species: evaluation by principal component and linear discriminant analyses.

Mushrooms are becoming relevant foods due to their nutritional, gastronomic and pharmacological properties, namely antioxidant, antitumor and antimicrobial properties. However, despite several mushroom species have been chemically characterized, the evaluation of triacylglycerol (TAG) profile remained nearly discarded. Since TAG was formerly used to assess the authentication of highly valued commercial oils, and the distribution of fatty acids on the glycerol molecule is genetically controlled, the potential of TAG profile to act as taxonomical marker was evaluated in 30 wild mushroom species. Principal component analysis and linear discriminant analysis were used to verify the taxonomical rank (order, family, genus or species) more related with the detected TAG profile. The results pointed out that the ability of TAG profile to discriminate mushroom samples increased for the lower taxonomical ranks, reaching a maximal performance for species discrimination. Since there is high resemblance among mushroom species belonging to the same genus and considering that conservation techniques applied to mushrooms often change their physical properties, this might be considered as a valuable outcome with important practical applications

Development of a novel methodology for the analysis of ergosterol in mushrooms

Sterols are important molecules in the unsaponifiable fraction of several matrices. Ergosterol, which is an important vitamin D2 precursor, is clearly the main sterol in mushrooms. Herein, an analytical method for ergosterol determination in cultivated and wild mushrooms was developed using high-performance liquid chromatography coupled to ultraviolet detection. The chromatographic separation was achieved in an Inertsil 100A ODS-3 reversed-phase column using an isocratic elution with acetonitrile/methanol (70:30, v/v) at a flow rate of 1 mL/min. Different extraction methodologies were tested, using n-hexane, methanol/dichloromethane (75:25, v/v) or chloroform/methanol (20:10, v/v). The method was optimised using Fistulina hepatica and proved to be reproductive and accurate. Ergosterol was the most abundant sterol by a greater extent in all mushrooms. In general, the cultivated species showed higher contents, mainly Agaricus bisporus and Lentinus edodes. Among wild species, Boletus edulis was the mushroom with the highest content in ergosterol. Results were expressed in fat content, dry weight and fresh weight bases. The assessment of ergosterol amounts might be very useful due to the bioactive potential that has been attributed to this molecule and its derivatives

Triacylglycerols profile and principal component analysis as a chemometric tool to identify wild edible mushroom genera

The Northeast of Portugal is among the European regions with high divers ity of wild mushrooms, some with recognized gastronomic value. Due to the high resemblance among mushroom species belonging to the same genus, finding a distinctive chemometric marker to identify mushroom species is a mandatory task. The lipidic fraction of a natural product has a characteristic pattern of triaeylglyccrol (TAG), comprising specific information due to the genetic control of the stereospecific distribution of fatty acids (FA) on the glycerol molecule, which is typical for each species. Principal component analysis (PCA) was previously applied to classify mushroom samples according to their fatty acids profile.121 However, despite TAG profile was used before to assess the authenticity of oils,l31 it was not used as taxonomical marker. Accordingly, TAG profile was evaluated in 30 wild mushroom species and the results were classified by PCA to identify their discriminant ability. TAG profiles obtained by high performance liquid chromatography coupled to an evaporative light scattering detector showed significant differences among species. The PCA biplot (1) showed that TAG profiles recorded for different mushroom genera may be used as an effective differentiating tool, especially when lowering the taxonomical rank, indicating that TAG profile is most related with the lowest ranks. Ln conclusion, this chemometric approach might be used as a practical tool to identify mushroom species

Ergosterol contents in mycorrhizal wild edible mushrooms: comparison by hierarchical cluster analysis

Sterols are important molecules of the unsaponifiable fraction in several matrices. In mushrooms, ergosterol, which is an important vitamin D2 precursor, is clearly the main sterol. Hierarchical cluster analysis (HCA) is an unsupervised learning method to standardized data, checking for similarities between sample groups. This method calculates the distances (or correlation) between all samples using a defined metric such as squared Euclidean distance or Chebychev distance. Hierarchical clustering is the most common approach in which clusters are formed sequentially. The most similar objects are first grouped, and these initial groups are merged according to their similarities. Eventually as the similarity decreases all subgroups are fused into a single cluster. Herein, ergosterol was quantified by high performance liquid chromatography, coupled with an ultraviolet detector, in some of the most appreciated mycorrhizal edible mushrooms (Amanita caesarea, Boletus edulis, Cantharellus cibarius, Lactarius deliciosus and Morchella esculenta). Considering fat content (percentage) and ergosterol contents in mg/g fat and mg/100 g of dry weight, two main groups were formed in the HCA: one aggregating A. caesarea and B. edulis and another constituted by C. cibarius, L. deliciosus and M. esculenta. These two groups derived from the higher contents presented by B. edulis and A. caesarea. The detected values indicate that mushrooms might act as a potential source of this vitamin D2 precursor, with special relevance for diets deprived of food products of animal origin.Foundation for Science and Technology (FCT, Portugal) and COMPETE/QREN/EU for the financial support of this work (research project PTDC/AGR-ALI/110062/2009) and to CIMO (strategic project PEst- OE/AGR/UI0690/2011). J.C.M. Barreira also thanks to FCT, POPH-QREN and FSE for his grant SFRH/BPD/72802/2010

Perfil de triacilgliceróis de cogumelos comestíveis: diferenciação inter-específica por análise discriminante linear

Os cogumelos têm ganho importância como bens alimentares devido às suas propriedades nutricionais, gastronómicas e farmacológicas. No entanto, apesar de diversas espécies de cogumelos terem já sido caracterizadas quimicamente, a avaliação do seu perfil em triacilgliceróis (TAG) tem sido alvo de menos estudos. O perfil em TAG foi já utilizado para avaliar a autenticidade de óleos comerciais de elevado valor, pelo que também poderá atuar como um potencial marcador taxonómico. Para verificar esta possibilidade, foi feita uma análise discriminante linear (ADL), tentando também definir-se qual o nível taxonómico mais relacionado com o perfil em TAG. Os resultados indicaram que o poder discriminante do perfil em TAG aumenta para os níveis taxonómicos mais específicos, atingindo um máximo na separação entre espécies. Uma vez que existem cogumelos pertencentes ao mesmo género que apresentam elevada semelhança no seu aspecto, e considerando ainda que as técnicas de conservação aplicadas aos cogumelos alteram muitas vezes as suas características físicas, os resultados obtidos neste trabalho poderão ter importantes aplicações práticas

Caso clínico pneumológico

Post-extubation acute pulmonary edema (PEAPE) is an uncommon complication of tracheal extubation, occurring in 0.1% of patients undergoing general anesthesia. It has rarely been described in pediatric age, but its incidence is thought to be underestimated, as many cases of post-operative respiratory distress may be misdiagnosed or unrecognized. A formerly healthy 15-year-old male diagnosed with acute appendicitis was submitted to a laparoscopic appendectomy under general anesthesia. Immediately after extubation, he developed signs and symptoms of respiratory distress, and chest radiograph was compatible with acute pulmonary edema. Due to suspicion of PEAPE, supplementary oxygen and intravenous furosemide were administered, with favorable outcome. PEAPE is a major anesthesia-related emergency, which may worsen the prognosis of low-risk surgical procedures. A high degree of suspicion should be maintained in children and adolescents presenting with signs of respiratory distress and hypoxia after general anesthesia, as prompt diagnosis and treatment are crucial for a favorable outcome.info:eu-repo/semantics/publishedVersio

Sugars profiles of different chestnut (Castanea sativa Mill.) and almond (Prunus dulcis) cultivars by HPLC-RI

Sugar profiles of different almond and chestnut cultivars were obtained by high-performance liquid chromatography (HPLC), by means of a refractive index (RI) detector. A solid-liquid extraction procedure was used in defatted and dried samples. The chromatographic separation was achieved using a Eurospher 100-5 NH2 column using an isocratic elution with acetonitrile/water (70:30, v/v) at a flow rate of 1.0 ml/min. All the compounds were separated in 16 min. The method was optimized and proved to be reproducible and accurate. Generally, more than 95% of sugars were identified for both matrixes. Sugars profiles were quite homogeneous for almond cultivars; sucrose was the main sugar (11.46±0.14 in Marcona to 22.23±0.59 in Ferragnes g/100 g of dried weight), followed by raffinose (0.71±0.05 in Ferraduel to 2.11±0.29 in Duro Italiano), glucose (0.42±0.12 in Pegarinhos two seeded to 1.47±0.19 in Ferragnes) and fructose (0.11±0.02 in Pegarinhos two seeded to 0.59±0.05 in Gloriette). Commercial cultivars proved to have higher sucrose contents, except in the case of Marcona. Nevertheless, chestnut cultivars revealed a high heterogeneity. Sucrose was the main sugar in Aveleira (22.05±1.48), Judia (23.30±0.83) and Longal (9.56± 0.91), while glucose was slightly prevalent in Boa Ventura (6.63±0.49). The observed variance could serve for intercultivar discrimination

Antioxidant potential of chestnut (Castanea sativa L.) and almond (Prunus dulcis L.) by-products.

The antioxidant properties of almond green husks (Cvs. Duro Italiano, Ferraduel, Ferranhês, Ferrastar and Orelha de Mula), chestnut skins and chestnut leaves (Cvs. Aveleira, Boa Ventura, Judia and Longal) were evaluated through several chemical and biochemical assays in order to provide a novel strategy to stimulate the application of waste products as new suppliers of useful bioactive compounds, namely antioxidants. All the assayed by-products revealed good antioxidant properties, with very low EC50 values (lower than 380 μg/mL), particularly for lipid peroxidation inhibition (lower than 140 μg/mL). The total phenols and flavonoids contents were also determined. The correlation between these bioactive compounds and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, reducing power, inhibition of β-carotene bleaching and inhibition of lipid peroxidation in pig brain tissue through formation of thiobarbituric acid reactive substances, was also obtained. Although, all the assayed by-products proved to have a high potential of application in new antioxidants formulations, chestnut skins and leaves demonstrated better results