1,606 research outputs found

    Oral liquid L-thyroxine (L-t4) may be better absorbed compared to L-T4 tablets following bariatric surgery.

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    Drug malabsorption is a potential concern after bariatric surgery. We present four case reports of hypothyroid patients who were well replaced with thyroxine tablets to euthyroid thyrotropin (TSH) levels prior to Roux-en-Y gastric bypass surgery. These patients developed elevated TSH levels after the surgery, the TSH responded reversibly to switching from treatment with oral tablets to a liquid formulation

    Discovery and evolution of the new black hole candidate Swift J1539.2-6227 during its 2008 outburst

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    We report on the discovery by the Swift Gamma-Ray Burst Explorer of the black hole candidate Swift J1539.2-6227 and the subsequent course of an outburst beginning in November 2008 and lasting at least seven months. The source was discovered during normal observations with the Swift Burst Alert Telescope (BAT) on 2008 November 25. An extended observing campaign with the Rossi X-Ray Timing Explorer (RXTE) and Swift provided near-daily coverage over 176 days, giving us a good opportunity to track the evolution of spectral and timing parameters with fine temporal resolution through a series of spectral states. The source was first detected in a hard state during which strong low-frequency quasi-periodic oscillations (QPOs) were detected. The QPOs persisted for about 35 days and a signature of the transition from the hard to soft intermediate states was seen in the timing data. The source entered a short-lived thermal state about 40 days after the start of the outburst. There were variations in spectral hardness as the source flux declined and returned to a hard state at the end of the outburst. The progression of spectral states and the nature of the timing features provide strong evidence that Swift J1539.2-6227 is a candidate black hole in a low-mass X-ray binary system.Comment: Accepted by the Astrophysical Journa

    An approximate empirical Bayesian method for large-scale linear-Gaussian inverse problems

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    We study Bayesian inference methods for solving linear inverse problems, focusing on hierarchical formulations where the prior or the likelihood function depend on unspecified hyperparameters. In practice, these hyperparameters are often determined via an empirical Bayesian method that maximizes the marginal likelihood function, i.e., the probability density of the data conditional on the hyperparameters. Evaluating the marginal likelihood, however, is computationally challenging for large-scale problems. In this work, we present a method to approximately evaluate marginal likelihood functions, based on a low-rank approximation of the update from the prior covariance to the posterior covariance. We show that this approximation is optimal in a minimax sense. Moreover, we provide an efficient algorithm to implement the proposed method, based on a combination of the randomized SVD and a spectral approximation method to compute square roots of the prior covariance matrix. Several numerical examples demonstrate good performance of the proposed method

    Morbid Obesity in Women is Associated to a Lower Prevalence of Thyroid Nodules.

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    BACKGROUND: Few studies have recently showed functional and morphological changes of the thyroid gland in relation to obesity. To our knowledge, no data are available about the prevalence of thyroid nodules in female obese patients. The aim of this study was to investigate the prevalence of thyroid nodules in morbidly obese women. METHODS: One hundred eight consecutive female obese patients were selected from those referred to our medical and surgery outpatients providing that following criteria were satisfied: (1) affected by morbid obesity (body mass index (BMI) >40 kg/m(2)); (2) no previous diagnosis of thyroid disease; (3) biochemically proven euthyroid state at the time of recruitment. Ninety-seven control subjects, constituted by normo-weight and/or slightly overweight (BMI ≤ 30 kg/m(2)) women, should satisfy the above criteria 2 and 3. All the subjects were submitted to ultrasound investigation. RESULTS: The two groups of patients displayed no differences for age and fT4 levels. Obese patients clearly showed a lower prevalence of thyroid nodules [odds ratio 0.294, 95% confidence interval 0.206-0.382]. A single nodule was found in 23% of obese patients as compared to 65% of control subjects (p < 0.0001). No difference for age (year) was found between obese and non-obese subjects with nodules (40.5 ± 8.2 vs. 44.2 ± 8.9, respectively, p = 0.07). CONCLUSIONS: Our data clearly show a significantly lower prevalence of thyroid nodules in morbidly obese patients. Further studies are needed to confirm and to understand this first observation

    Synthesis and characterization of adsorbents for the elimination of nitrates and bromates from water aiming to develop a continuous oxyanion water elimination system

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    It is known that the excess of oxyanions such as NO 3 and BrO 3 in drinking water affects its quality. In this work, three adsorbents (montmorillonite (Mt), silica (Si), and diatomaceous earth) loaded with hexadecyl- (H) and octadecyl-trimethylammonium (O) were used to remove these oxyanions from aqueous solutions by adsorption. In batch systems, the highest NO 3 removal was obtained with Mt modified with H and O (Mt-H and Mt-O), attaining 33% and 50%, respectively, while for BrO 3 removal Si modified with H and O, Si-H and Si-O samples, reached 38% and 42%, respectively. A direct relationship between the adsorption capacity of NO 3 and BrO 3 and the mass of the adsorbent was found in column filtration tests with Mt-O and Mt-H samples in standard solution and real groundwater samples. The adsorption capacity of the column, in the groundwater sample, remained constant after two reuses.The results obtained are promising for the development of a continuous oxyanion removal system containing the low-cost clay Mt modified with either H or O.Fil: Azaro, M.. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Flores, Federico Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; ArgentinaFil: Casella, Mónica Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Peroni, B.. Universidad Nacional de La Plata; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Rodríguez, C.. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Torres Sanchez, Rosa Maria. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; ArgentinaFil: Jaworski, María Angélica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentin

    First measurement of the 14N(p,gamma)15O cross section down to 70 keV

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    In stars with temperatures above 20*10^6 K, hydrogen burning is dominated by the CNO cycle. Its rate is determined by the slowest process, the 14N(p,gamma)15O reaction. Deep underground in Italy's Gran Sasso laboratory, at the LUNA 400 kV accelerator, the cross section of this reaction has been measured at energies much lower than ever achieved before. Using a windowless gas target and a 4pi BGO summing detector, direct cross section data has been obtained down to 70 keV, reaching a value of 0.24 picobarn. The Gamow peak has been covered by experimental data for several scenarios of stable and explosive hydrogen burning. In addition, the strength of the 259 keV resonance has been remeasured. The thermonuclear reaction rate has been calculated for temperatures 90 - 300 *10^6 K, for the first time with negligible impact from extrapolations

    Feasibility of low energy radiative capture experiments at the LUNA underground accelerator facility

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    The LUNA (Laboratory Underground for Nuclear Astrophysics) facility has been designed to study nuclear reactions of astrophysical interest. It is located deep underground in the Gran Sasso National Laboratory, Italy. Two electrostatic accelerators, with 50 and 400 kV maximum voltage, in combination with solid and gas target setups allowed to measure the total cross sections of the radiative capture reactions 2^2H(p,γ\gamma)3He and 14^{14}N(p,γ\gamma)15^{15}O within their relevant Gamow peaks. We report on the gamma background in the Gran Sasso laboratory measured by germanium and bismuth germanate detectors, with and without an incident proton beam. A method to localize the sources of beam induced background using the Doppler shift of emitted gamma rays is presented. The feasibility of radiative capture studies at energies of astrophysical interest is discussed for several experimental scenarios.Comment: Submitted to Eur. Phys. J.

    Poliomielite associada à vacina: descrição de caso por transmissão domiciliar

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    Poliomyelitis associated with live strain vaccine is defined as the paralytic form of the acute anterior poliomyelitis related to the vaccine strain. Since these strains behave similarly to the wild-type virus, we can differentiate, epidemiologically, two types of vaccine-associated poliomyelitis: cases in which the patient was vaccinated and cases in which the patient had had contact with vaccinated individuals. We herein present the case of an unvaccinated child, with a clinical picture of an acute anterior poliomyelitis associated with the live strain vaccine, whose brother received the Sabin vaccine 20 days before the onset of the symptoms. Vaccine strain of the type 3 poliovirus was isolated in fecal culture and a presented mutation in nucleotide 472 (C;®;U) in the 5' non-coding region, which is strongly related to the higher strain virulence.A poliomielite associada à vacina oral é definida como a forma paralítica da poliomielite anterior aguda decorrente da cepa vacinal. Uma vez que o comportamento da cepa vacinal é semelhante ao do vírus selvagem, epidemiologicamente podemos distinguir dois tipos de poliomielite associada à vacina, os casos em que o paciente foi vacinado e os casos em que o paciente teve contato com pessoas que receberam a vacina. Apresentamos o caso de um lactente não vacinado, que apresentou quadro de poliomielite anterior aguda associada à vacina oral, cujo irmão havia recebido a vacina Sabin 20 dias antes do início do quadro clínico. Na cultura de fezes do paciente foi isolado o poliovírus tipo 3, cepa vacinal, que apresentava mutação do nucleotídeo 472 (C;®;U) na região 5' não codificadora, a qual está significativamente relacionada com a maior virulência da cepa

    Acute outcome after a single cryoballoon ablation: Comparison between Arctic Front Advance and Arctic Front Advance PRO

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    BACKGROUND: The novel fourth-generation cryoballoon (CB4) potentially allows for enhanced catheter maneuverability and more frequent capture of pulmonary vein (PV) potentials which can be used to monitor real-time PV isolation (PVI). The aim of our study is to compare the acute procedural endpoints between the CB4 and second-generation cryoballoon (CB2). METHODS: A single-center retrospective chart review was used to examine 50 consecutive patients with drug-refractory atrial fibrillation undergoing CB4-based PVI. Procedural data and acute success of these patients were compared to 50 propensity-matched controls who underwent cryoballoon ablation procedure using CB2. RESULTS: Procedures performed with the CB4 showed significant shorter fluoroscopy time (14.8 \ub1 5.5 vs 18.0 \ub1 6.5 minutes, P = .04), shorter procedure time (58.3 \ub1 15.7 vs 65.3 \ub1 21 minutes, P = .13), and shorter total ablation time (10.8 \ub1 1.5 vs 13.8 \ub1 1.9 minutes, P = .42). The real-time PVI visualization rate was 33.3% in the CB2 group and 74.7% in the CB4 group (P &lt; .001). CB4 was correlated to significant increase of acute real-time recordings with regard to all the single PV (left superior PV: 58% vs 84%, P = .02; left inferior PV: 26% vs 71%, P = .001; right superior PV 29% vs 61%, P = .01; and right inferior PV 19% vs 58%, P = .002). CONCLUSION: The CB4 was more often able to capture real-time recordings of PV potentials and the subsequent acute PV isolation

    Apendicite Aguda – Clínica Versus Histologia

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    Introdução: A apendicite aguda continua a ser um dos principais diagnósticos nos Serviços de Cirurgia Pediátrica. A taxa de apendicectomia negativa (apendicectomia sem evidência histológica de patologia), frequentemente utilizada como índice de qualidade hospitalar, permanece alta, apesar dos esforços para a reduzir, especialmente em crianças com menos de 6 anos. Objectivos: Os objectivos primários foram: o cálculo da taxa de apendicectomia negativa, da concordância entre diagnóstico clínico (pós-operatório) e diagnóstico histológico e a caracterização da discordância diagnóstica por tipo de apendicite (fleimonosa, gangrenada, perfurada). A caracterização dos grupos apendicectomia negativa (A) e apendicites perfuradas (B), bem como a relação entre estes dois grupos ao longo dos anos, constituíram objectivos secundários. Material e Método: Estudo retrospectivo dos dados clínicos de 1000 doentes consecutivamente operados com o diagnóstico clínico de apendicite aguda, no Hospital de Dona Estefânia, no período de 1 de Janeiro 2003 – 30 de Setembro 2007, procedendo-se à consulta da folha de requisição de exame histo-patológico enviada para o Serviço de Anatomia Patológica. Foram revistos os dados epidemiológicos, a qualidade da informação da referida folha de requisição e calculada a taxa de apendicectomia negativa nesta amostra. Resultados: O diagnóstico clínico pós-operatório foi concordante com o diagnóstico histológico em cerca de 60% casos, sendo subvalorizado ou sobrevalorizado nos restantes casos. A taxa de apendicectomia negativa observada foi de 5,5%, o que está abaixo dos valores apresentados na literatura. Conclusões: As apendicectomias negativas devem ser um “mal menor” em relação às apendicites perfuradas. A discordância clínico- histológica pode ter implicações médico-legais e tem seguramente implicações clínicas e económicas pelo que urge reavaliar o modelo de abordagem desta patologia tão frequente.
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