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107. A modified split-anode detector for the study of the anode region of atmospheric pressure arc plasmas.

Author

Vilarinho, L. O. and Fanara, C.

Subjects
ATMOSPHERIC pressure, ANODES, DETECTORS, PHYSICAL measurements
Abstract

The split-anode technique developed in the 1960s for the study of the anode region of atmospheric pressure arcs has been modified in order to reduce (and subsequently eliminate) the need for double Abel inversion to reconstruct the local physical information. A first version of a detector based on a conductive sheet is presented and the performances of the new set-up are compared under varying arc conditions. Good stability against erratic arcing was obtained using relatively high arc travel speed (60 mm s-1). The signal shape shows a good degree of symmetry in forward and backward motion of the arc through the anode interface, although the disturbance of the latter cannot be avoided completely. The voltage readings obtained at several arc currents fall in between two sets of previously published data. Preliminary results on current density are also given. [ABSTRACT FROM AUTHOR]

Published
2004
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109. GAMT deficiency

Author

Mercimek-Mahmutoglu, S, Stoeckler-Ipsiroglu, S, Adami, A, Appleton, R, Araújo, H Caldeira, Duran, M, Ensenauer, R, Fernandez-Alvarez, E, Garcia, P, Grolik, C, Item, C B., Leuzzi, V, Marquardt, I, Mühl, A, Saelke-Kellermann, R A., Salomons, G S., Schulze, A, Surtees, R, Knaap, M S. van der, Vasconcelos, R, Verhoeven, N M., Vilarinho, L, Wilichowski, E, and Jakobs, C

Abstract

Guanidinoactetate methyltransferase (GAMT) deficiency is an autosomal recessive disorder of creatine synthesis. The authors analyzed clinical, biochemical, and molecular findings in 27 patients.

Published
2006
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117. Spectrum of CBS mutations in 16 homocystinuric patients from the Iberian Peninsula: high prevalence of T191M and absence of I278T or G307S

Author

Urreizti, R., Balcells, S., Rodés, M., Vilarinho, L., Baldellou, A., Maria Luz Couce, Muñoz, C., Campistol, J., Pintó, X., Vilaseca, M. A., and Grinberg, D.

Abstract

Homocystinuria due to cystathionine beta-synthase (CBS) deficiency has been extensively studied, but to date, no spectrum of CBS mutations of Spanish homocystinuric patients has been reported. Here we present a mutation analysis of thirteen Spanish and three Portuguese unrelated homocystinuric patients. Ten mutations were found to account for the thirty-two mutant alleles and five of these (C275Y, L338P, S349N, R379Q, and L456P) are reported here for the first time. All five novel mutations were found to affect evolutionarily conserved residues suggesting that they may impair enzyme function. Interestingly, neither of the two common CBS mutations, I278T and G307S, was detected in this series, and no patient was found to respond to pyrodoxine. Enzyme activities in cultured fibroblasts from 10 of the patients were assayed, and they ranged from 0 to 13 % of controls analyzed in parallel. The T191M mutation (which has only ever been reported once before in a Spanish patient) accounted for 50% of the mutant alleles. Comparison of the clinical data of seven patients homozygous for T191M indicated that this genotype is a poor predictor of the phenotype. A common haplotype was identified in all the T191M chromosomes of Spanish origin, while a different one was present in the four T191M chromosomes from Portuguese patients.

119. Guidelines for diagnosis and management of the cobalamin-related remethylation disorders cblC, cblD, cblE, cblF, cblG, cblJ and MTHFR deficiency

Author

Martina Huemer, Diodato D, Schwahn B, Schiff M, Bandeira A, Jf, Benoist, Burlina A, Cerone R, Ml, Couce, Garcia-Cazorla A, la Marca G, Pasquini E, Vilarinho L, Jd, Weisfeld-Adams, Kožich V, Blom H, Baumgartner MR, and Dionisi-Vici C

Abstract

BACKGROUND: Remethylation defects are rare inherited disorders in which impaired remethylation of homocysteine to methionine leads to accumulation of homocysteine and perturbation of numerous methylation reactions. OBJECTIVE: To summarise clinical and biochemical characteristics of these severe disorders and to provide guidelines on diagnosis and management. DATA SOURCES: Review, evaluation and discussion of the medical literature (Medline, Cochrane databases) by a panel of experts on these rare diseases following the GRADE approach. KEY RECOMMENDATIONS: We strongly recommend measuring plasma total homocysteine in any patient presenting with the combination of neurological and/or visual and/or haematological symptoms, subacute spinal cord degeneration, atypical haemolytic uraemic syndrome or unexplained vascular thrombosis. We strongly recommend to initiate treatment with parenteral hydroxocobalamin without delay in any suspected remethylation disorder; it significantly improves survival and incidence of severe complications. We strongly recommend betaine treatment in individuals with MTHFR deficiency; it improves the outcome and prevents disease when given early.

138. SCREENING FOR BH4-RESPONSIVENESS IN PORTUGUESE PKU PATIENTS

Author

Rivera, I., Paula Leandro, Gaspar, A., Antunes, M. Lobo, Vilarinho, L., Almeida, I. Tavares, and Repositório da Universidade de Lisboa

Subjects
Genetics & Heredity, Biochemistry & Molecular Biology, Medicine, Research & Experimental
Abstract

Made available in DSpace on 2015-12-30T10:17:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2009

142. 'DOUBLE TROUBLE OR DIGENIC DISORDER IN COMPLEX I DEFICIENCY

Author

Ferreira, M., Almeida, L. S., Nogueira, C., Furtado, F., Evangelista, T., Filippo M Santorelli, and Vilarinho, L.

Subjects
Doenças Mitocondriais, Défice de Complexo I, Doenças Genéticas
Abstract

Complex I (CI) deficiency is a defect of OXPHOS caused by mutations in the mitochondrial or nuclear genomes. To date disease-causing mutations have been reported in all mitochondrial-encoded subunits and 22 nuclear genes. In about 50% of the patients no mutations are found, suggesting that undiscovered factors are an important cause of disease. In this study we report a consanguineous family from Southern Portugal with three affected children presenting with CI deficiency and 3-methylglutaconic aciduria type IV.

144. Methodology for Parameter Calculation of VP-GMAW.

Author

VILARINHO, L. O., NASCIMENTO, A. S., FERNANDES, D. B., and MOTA, C. A. M.

Subjects
WELDING industry, ELECTRIC power systems, THERMAL conductivity of metals, SHIELDED metal arc welding, ELECTRODES, ALUMINUM
Abstract

The development of electronic power sources has allowed the study of innovative processes, generally with the objective to improve productivity allied to low levels of heat input. The existing processes are based on metal transfer evaluation and the development of different waveforms for improving the process control. The variable polarity gas metal arc welding (VP-GMAW) process is a derivative process of conventional GMAW that joins the advantages of the use of positive polarity, as the good stability of arc and cathodic cleaning, with the supplied ones for the negative polarity, which is the high melting rate of the electrode and low heat input to the base metal. However, this process still has a limited use due to shortage of technical and scientific literature devoted to parameter calculation, as the one observed for DC pulsed GMAW(Refs. 1,2). Also, most of literature is dedicated to aluminum welding (Refs. 3-7). Thus, in this work, a methodology for determination of the process parameters is proposed and evaluated for different waveforms and variable electrode negative ratio (percentage of time at negative polarity). Both arc and metal transfer stabilities are observed as indicators. The experimental procedure was carried out with bead-on-plate welding of mild steel and employing high-speed filming and analysis of bead geometrical features. It is concluded that the proposed methodology is suitable for parameters calculation during VP-GMAW, where a positive base time after the negative one is more effective in reducing abrupt polarity changes and therefore provides more stable arcs and avoids spattering. Finally, it is possible to select the best combination of waveform and electrode-negative time for the application, using the equations presented to predict the weld bead geometry. [ABSTRACT FROM AUTHOR]

Published
2009

145. The Effect of Out-of-Phase Pulsing on Metal Transfer in Twin-Wire GMA Welding at High Current Level.

Author

Scotti, A., Morais, C. O., and Vilarinho, L. O.

Subjects
GAS metal arc welding, ELECTRIC welding, WELDING research, WELDING industry, WELDING equipment
Abstract

The article examines the deposit transfer and arc characteristics of welding twin-wire gas metal arc (GMA) at high current level using non-pulsing machines. Result of the study shows that application of out-of-phase pulsing on GMA welding process can provide quality weldments as it does not impose any reduction of arc and droplet attractions at the specified current level.

Published
2006

146. Novel L2HGDH mutations in 21 patients with L-2-hydroxyglutaric aciduria of Portuguese origin.

Author

Vilarinho, L., Cardoso, M.L., Gaspar, P., Barbot, C., Azevedo, L., Diogo, L., Santos, M., Carrilho, I., Fineza, I., Kok, F., Chorão, R., Alegria, P., Martins, E., Teixeira, J., Cabral Fernandes, H., Verhoeven, N.M., Salomons, G.S., Santorelli, F.M., Cabral, P., and Amorim, A.

Abstract

We studied 21 patients, from 18 families, with L-2-hydroxyglutaric aciduria (L-2-HGA), a rare neurometabolic disorder with a homogeneous presentation: progressive neurodegeneration with extrapyramidal and cerebellar signs, seizures, and subcortical leukoencephalopathy. Increased levels of L-2-hydroxyglutaric acid in body fluids proved the diagnosis of L-2-HGA in all 21 patients. We analyzed the L-2-HGA gene (L2HGDH), recently found to be mutated in consanguineous families with L-2-HGA, and identified seven novel mutations in 15 families. Three mutations appeared to be particularly prevalent in this Portuguese panel: a frameshift mutation (c.529delC) was detected in 12 out of 30 mutant alleles (40%), a nonsense mutation (c.208C>T; p.Arg70X) in 7/30 alleles (23%), and a missense mutation (c.293A>G; p.His98Arg) in four out of 30 mutant alleles (13%), suggesting that common origin may exist. Furthermore, two novel missense (c.169G>A; p.Gly57Arg, c.1301A>C; p.His434Pro) and two splice error (c.257-2A>G, c.907-2A>G) mutations were found. All the mutations presumably lead to loss-of-function with no relationship between clinical signs, progression of the disease, levels of L-2-HGA and site of the mutation. In the three remaining families, no pathogenic mutations in the L-2-HGA were found, which suggests either alterations in regulatory regions of the gene or of its intervening sequences, compound heterozygosity for large genomic deletion and, or further genetic heterogeneity. © 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Published
2005
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