1,523 research outputs found
Towards fast simulation of environmental fluid mechanics with multi-scale graph neural networks
Numerical simulators are essential tools in the study of natural fluid-systems, but their performance often limits application in practice. Recent machine-learning approaches have demonstrated their ability to accelerate spatio-temporal predictions, although, with only moderate accuracy in comparison. Here we introduce MultiScaleGNN, a novel multi-scale graph neural network model for learning to infer unsteady continuum mechanics in problems encompassing a range of length scales and complex boundary geometries. We demonstrate this method on advection problems and incompressible fluid dynamics, both fundamental phenomena in oceanic and atmospheric processes. Our results show good extrapolation to new domain geometries and parameters for long-term temporal simulations. Simulations obtained with MultiScaleGNN are between two and four orders of magnitude faster than those on which it was trained
Ochratoxin A in nephropathic patients from two cities of central zone in Portugal
Ochratoxin A (OTA) produced by Aspergillus and Penicilliumgenera contaminates several foods. OTA is nephrotoxic to all animal species studied so far, and most likely to humans, who show the longest half-life for elimination of this toxin among all examined species. OTA has other toxic effects such as teratogenicity, immunotoxiity, genotoxicity, and is also mutagenic and carcinogenic, all of which lead to life-threatening pathologies through several molecular pathways.http://www.sciencedirect.com/science/article/B6TGX-4MS9JXF-2/1/6c0f4b2a3b77c84ec1f89cdefb65913
Nasopharyngeal tuberculosis - A case report
A tuberculose (TB) é a doença infecciosa mais comum em todo o mundo. Tem várias apresentações possíveis, podendo atingir vários órgãos e inclusive mimetizar outras patologias, incluindo carcinomas. O aparecimento na nasofaringe é raro e o principal sintoma são linfadenopatias cervicais.
Descreve-se um caso clínico de um adolescente de 16 anos, cujo diagnóstico de tuberculose nasofaríngea foi dificultado pela localização rara e pela negatividade da maior parte dos exames utilizados para o diagnóstico. O doente foi sujeito a terapêutica com tuberculostáticos durante um período de 9 meses verificando-se uma regressão completa do quadro. Muitas vezes só através da prova terapêutica é possível a atribuição de um diagnóstico definitivo. Em doentes com neoformações na nasofaringe e linfadenopatias cervicais é importante considerar TB como um diagnóstico diferencial.info:eu-repo/semantics/publishedVersio
Peroxisomal metabolism alterations associated to Z. aethiopica spathe senescence and regreening
The development of the C3 monocot Zantedeschia aethiopica floral spathe has been used as a natural model for studying the physiological and biochemical features of senescence. This photosynthetic leaf-like organ undergoes senescence displaying the common features of leaf senescence, such as loss of protein, chlorophyll and a decline on photosynthetic ability. Fruiting inhibits the ongoing spathe senescence and the regreening of its abaxial parenchyma cells is observed. Previous results have suggested that during the spathe whitening the peroxisomes differentiate into glyoxysomes and that the regreening process is followed by their conversion back into peroxisomes, resulting in the re-acquisition of photorespiratory capacity.
In this work, changes in peroxisomal metabolism were studied in what concerns key-enzymes of glyoxylate and glycolate pathways. An increase in isocitrate lyase (ICL) activity during the late stages of spathe whitening suggests that there is an induction of glyoxysomal metabolism. The increase of hydroxypyruvate reductase (HPR) activity during spathe regreening, accompanied with the decrease of the glyoxylate key-enzyme ICL, points to an induction of leaf-type peroxisome metabolism thus suggesting the conversion of glyoxysomes back into peroxisomes. This hypothesis is further supported by the expression analysis of genes encoding enzymes from glycolate and glyoxylate pathways. The results will be discussed taking into account hydrogen peroxide levels evaluated during the time course of Z. aethiopica spathe development.Fundação para a Ciência e a Tecnologia (FCT) - grant ref. SFRH/BD/12081/2003
Changes in peroxisomal metabolism during Zantedeschia aethiopica spathe senescence and regreening : differential expression of two catalase genes
Poster apresentado no 14th Federation of European Societies of Plant Biology Congress, em 2004, Cracóvia, Polónia.Zantedeschia aethiopica spathe undergoes whitening displaying the common features of foliar senescence. After pollination, the spathe region surrounding the fruits undergo regreening, thus reacquiring photosynthetic ability. In this work, changes in peroxisomal metabolism were studied in what concerns key-enzymes of glyoxylate and glycolate pathways. Putative roles for CAT1 and CAT2 are discussed.
Material and Methods: Spathes during the time course of senescence and regreening were harvested from field-grown plants. The content in hydrogen peroxide (H2O2) followed Loreto et al (2001). Catalase activity was determined by following the decomposition of H2O2 at 240 nm (Aebi, 1983). Northern analysis was performed using Z. aethiopica Cat1 (AF207906) and Cat2 (AF332973) cDNAs as homologous probes. The activity of the glyoxysomal-marker enzyme isocitrate lyase (ICL) and leaf-type peroxisomal marker enzyme hydroxypyruvate reductase (HPR) were determined according to Zelitch (1988) and Liang et al. (1984), respectively.
Results and Conclusions: Changes in ICL and HPR activitiy suggest that during Z. aethiopica spathe development there is an induction of glyoxysomal metabolism during the late stages of whitening, followed by the induction of leaf-type peroxisome metabolism during regreening. In addition, the levels of H2O2 during the initial stages of spathe whitening seems to paralell catalase activity. As the transcript levels of Cat1 increase until the late stages of spathe whitening, CAT1 is probably associated to scavenging of glyoxysomal H2O2. The higher expression of Cat2 during spathe regreening suggests that CAT2 is specifically associated to photorespiratory H2O2 decomposition. However, as Cat1 expression is also strongly induced during regreening, a dual role of CAT1 in scavenging leaf-type peroxisomal and glyoxysomal H2O2 can also be considered.Fundação para a Ciência e a Tecnologia (FCT) - Ref. SFRH/BD/12081/2003
Changes in peroxisomal metabolism during Z. aethiopica spathe senescence and regreening : differential expression of two catalase genes
Zantedeschia aethiopica spathe undergoes whitening displaying the common features of foliar senescence. After pollination, the spathe region surrounding the fruits undergo regreening, thus reacquiring photosynthetic ability. In this work, changes in peroxisomal metabolism were studied in what concerns key-enzymes of glyoxylate and glycolate pathways. Putative roles for CAT1 and CAT2 are discussed.
Material and Methods: Spathes during the time course of senescence and regreening were harvested from field-grown plants. The content in hydrogen peroxide (H2O2) followed Loreto et al (2001). Catalase activity was determined by following the decomposition of H2O2 at 240 nm (Aebi, 1983). Northern analysis was performed using Z. aethiopica Cat1 (AF207906) and Cat2 (AF332973) cDNAs as homologous probes. The activity of the glyoxysomal-marker enzyme isocitrate lyase (ICL) and leaf-type peroxisomal marker enzyme hydroxypyruvate reductase (HPR) were determined according to Zelitch (1988) and Liang et al. (1984), respectively.
Results and Conclusions: Changes in ICL and HPR activitiy suggest that during Z. aethiopica spathe development there is an induction of glyoxysomal metabolism during the late stages of whitening, followed by the induction of leaf-type peroxisome metabolism during regreening. In addition, the levels of H2O2 during the initial stages of spathe whitening seems to paralell catalase activity. As the transcript levels of Cat1 increase until the late stages of spathe whitening, CAT1 is probably associated to scavenging of glyoxysomal H2O2. The higher expression of Cat2 during spathe regreening suggests that CAT2 is specifically associated to photorespiratory H2O2 decomposition. However, as Cat1 expression is also strongly induced during regreening, a dual role of CAT1 in scavenging leaf-type peroxisomal and glyoxysomal H2O2 can also be considered.Fundação para a Ciência e a Tecnologia (FCT) - grant ref. SFRH/BD/10899/2002
Validação de um método para detecção e quantificação de soja culticance tolerante a herbicidas imidazolinonas por PCR convencional e quantitativo.
bitstream/item/71972/1/ID-30956.pd
SeqBreed : a python tool to evaluate genomic prediction in complex scenarios
Background: Genomic prediction (GP) is a method whereby DNA polymorphism information is used to predict breeding values for complex traits. Although GP can significantly enhance predictive accuracy, it can be expensive and difficult to implement. To help design optimum breeding programs and experiments, including genome-wide association studies and genomic selection experiments, we have developed SeqBreed, a generic and flexible forward simulator programmed in python3. Results: SeqBreed accommodates sex and mitochondrion chromosomes as well as autopolyploidy. It can simulate any number of complex phenotypes that are determined by any number of causal loci. SeqBreed implements several GP methods, including genomic best linear unbiased prediction (GBLUP), single-step GBLUP, pedigree-based BLUP, and mass selection. We illustrate its functionality with Drosophila genome reference panel (DGRP) sequence data and with tetraploid potato genotype data. Conclusions: SeqBreed is a flexible and easy to use tool that can be used to optimize GP or genome-wide association studies. It incorporates some of the most popular GP methods and includes several visualization tools. Code is open and can be freely modified. Software, documentation, and examples are available at https://github.com/miguelperezenciso/SeqBreed
Chlormequat selective electrodes: construction, evaluation and application at FIA systems
A flow injection analysis (FIA) system having a chlormequat selective electrode is proposed. Several electrodes
with poly(vinyl chloride) based membranes were constructed for this purpose. Comparative characterization
suggestedthe use of membrane with chlormequat tetraphenylborate and dibutylphthalate. On a
single-line FIA set-up, operating with 1x10-2 mol L-1 ionic strength and 6.3 pH, calibration curves presented
slopes of 53.6±0.4mV decade-1 within 5.0x10-6 and1.0x10-3 mol L-1, andsquaredcorrelation coefficients
>0.9953. The detection limit was 2.2x10-6 mol L-1 and the repeatability equal to ±0.68mV
(0.7%). A dual-channel FIA manifold was therefore constructed, enabling automatic attainment of previous
ionic strength andpH conditions and thus eliminating sample preparation steps. Slopes of 45.5±0.2mV decade
-1 along a concentration range of 8.0x10-6 to 1.0x10-3 mol L-1 with a repeatability ±0.4mV (0.69%)
were obtained. Analyses of real samples were performed, and recovery gave results ranging from 96.6 to
101.1%
Identification of Zantedeschia aethiopica Cat1 and Cat2 catalase genes and their expression analysis during spathe senescence and regreening
Plants encode catalase (CAT; EC 1.11.1.6) as multigene families, which may reflect the multiple and diverse roles played by this enzyme. Catalases from higher plants can be subdivided into three distinct types, according to their phylogenetic relationship. However, there is not a specific correlation of phylogeny and function within these groups, as catalases from the same type can play different specific roles. We report on the characterization of two monocot catalase genes from Zantedeschia aethiopica (a C_3-type Araceae) and its expression analysis during spathe senescence and regreening. Z. aethiopica CAT2 appears to play an exclusive role in scavenging photorespiratory H_2O_2, but is more phylogenetically related to the unspecific Zea mays CAT3 and Oryza sativa CATA than to the photorespiratory-related Zea mays CAT2 and Oryza sativa CATC. Z. aethiopica CAT1 is more phylogenetically related to Zea mays CAT1 and Oryza sativa CATB and appears to have a dual role in scavenging glyoxysomal and peroxisomal H_2O_2.Fundação para a Ciência e a Tecnologia (FCT) - PRAXIS XXI/BD/16280/98 , SFRH/BD/12081/2003
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