16,895 research outputs found

    Singular quasilinear elliptic systems in RN\mathbb{R}^N

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    The existence of positive weak solutions to a singular quasilinear elliptic system in the whole space is established via suitable a priori estimates and Schauder's fixed point theorem

    Charge and Magnetic Flux Correlations in Chern-Simons Theory with Fermions

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    Charge and magnetic flux bearing operators are introduced in Chern-Simons theory both in its pure form and when it is coupled to fermions. The magnetic flux creation operator turns out to be the Wilson line. The euclidean correlation functions of these operators are shown to be local and are evaluated exactly in the pure case and through an expansion in the inverse fermion mass whenever these are present. Physical states only occur in the presence of fermions and consist of composite charge-magnetic flux carrying states which are in general anyonic. The large distance behavior of the correlation functions indicates the condensation of charge and magnetic flux.Comment: Latex, 17 page

    Chemical composition of stellar populations in Omega Centauri

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    We derive abundances of Fe, Na, O, and s-elements from GIRAFFE@VLT spectra for more than 200 red giant stars in the Milky Way satellite Omega Centauri. Our preliminary results are that: (i) we confirm that Omega Centauri exibiths large star-to-star metallicity variations (āˆ¼\sim 1.4 dex); (ii) the metallicity distribution reveals the presence of at least five stellar populations with different [Fe/H]; (iii) a clear Na-O anticorrelation is clearly observed for the metal-poor and metal-intermediate populations while apparently the anticorrelation disappears for the most metal-rich populations. Interestingly the Na level grows with iron.Comment: 2 pages, 2 figures. To appear in the proceedings of IAU Symp. 268 "Light elements in the Universe" (C. Charbonnel, M. Tosi, F. Primas, C. Chiappini, eds., Cambridge Univ. Press

    Cholangiocarcinoma in sclerosing cholangitis. The role of liver transplantation

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    Our experience with patients who underwent orthotopic liver transplantation for sclerosing cholangitis at the University of Pittsburgh Health Center between March 1980 and March 1988 is reported here. Ten patients had an associated cholangiocarcinoma. Six of these patients died of recurrent, disseminated cancer, usually before one year. One patient died of sepsis, while three are alive and apparently free of tumor four months to almost two years later. Pre-operative identification of a possible cholangiocarcinoma and complete resection are of crucial importance. Adjuvant therapy, especially pre-transplant radiation with a prophylactic purpose is still being evaluated

    The Contributions of Skeletal Muscle PKC Theta to Diet-Induced Obesity

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    Protein Kinase C- Theta (PKCĪø) is a gene predominantly expressed in hematopoietic cells and skeletal muscle. In skeletal muscle, PKCĪø regulates fat metabolism and insulin sensitivity. PKCĪø activity increases in response to high levels of diacylglycerol in the cell, a common outcome of chronic high fat diet consumption and obesity. PKCĪø is associated with skeletal muscle metabolic dysfunction, which may exacerbate weight gain and metabolic disease. The purpose of this study was to test the hypothesis that the selective deletion of PKCĪø from skeletal muscle protects against diet-induced obesity. Mice lacking PKCĪø in skeletal muscle were created using Cre-Lox recombination. At weaning, control (PKCĪøSkM+/+) and knockout (PKCĪøSkM-/-) mice were randomly assigned to regular or high fat diet (RD or HFD, respectively) groups. Mouse weights were taken weekly for 15 weeks. During the 15-week diet intervention, male PKCĪøSkM+/+ mice on a HFD became obese. Male PKCĪøSkM-/- mice consuming a HFD showed attenuated weight gain, which was similar to mice on a RD. This trend was not present for female mice, in which weight changed to a similar magnitude independent of diet and genotype. In conclusion, PKC-Īø in the skeletal muscle may contribute to the regulation of diet-induced obesity. It is unclear whether these affects are sex specific

    PRRT2 gene variant in a child with dysmorphic features, congenital microcephaly, and severe epileptic seizures: genotype-phenotype correlation?

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    BACKGROUND: Mutations in Proline-rich Transmembrane Protein 2 (PRRT2) have been primarily associated with individuals presenting with infantile epilepsy, including benign familial infantile epilepsy, benign infantile epilepsy, and benign myoclonus of early infancy, and/or with dyskinetic paroxysms such as paroxysmal kinesigenic dyskinesia, paroxysmal non-kinesigenic dyskinesia, and exercise-induced dyskinesia. However, the clinical manifestations of this disorder vary widely. PRRT2 encodes a protein expressed in the central nervous system that is mainly localized in the pre-synaptic neurons and is involved in the modulation of synaptic neurotransmitter release. The anomalous function of this gene has been proposed to cause dysregulation of neuronal excitability and cerebral disorders. CASE PRESENTATION: We hereby report on a young child followed-up for three years who presents with a spectrum of clinical manifestations such as congenital microcephaly, dysmorphic features, severe intellectual disability, and drug-resistant epileptic encephalopathy in association with a synonymous variant in PRRT2 gene (c.501Cā€‰>ā€‰T; p.Thr167Ile) of unknown clinical significance variant (VUS) revealed by diagnostic exome sequencing. CONCLUSION: Several hypotheses have been advanced on the specific role that PRRT2 gene mutations play to cause the clinical features of affected patients. To our knowledge, the severe phenotype seen in this case has never been reported in association with any clinically actionable variant, as the missense substitution detected in PRRT2 gene. Intriguingly, the same mutation was reported in the healthy father: the action of modifying factors in the affected child may be hypothesized. The report of similar observations could extend the spectrum of clinical manifestations linked to this mutation

    Relaxation, pre-thermalization and diffusion in a noisy Quantum Ising Chain

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    We study the dynamics of thermalization resulting from a time-dependent noise in a Quantum Ising Chain subject to a sudden quench of the transverse magnetic field. For weak noise the dynamics shows a pre-thermalized state at intermediate time scales, eventually drifting towards an asymptotic infinite temperature steady state characterized by diffusive behavior. By computing analytically the density of kinks, as well as the transverse and longitudinal magnetic field correlators, we characterize these two regimes, their observability and their signatures in the various physical quantities.Comment: 5 pages, 2 figures. Accepted for publication in PRB Rapid Communication

    Total hepatectomy and liver transplant for hepatocellular adenomatosis and focal nodular hyperplasia.

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    Extensive hepatocellular adenomatosis (HA) and focal nodular hyperplasia (FNH) represent a proliferation of hepatic cells that occurs most frequently in women. These lesions are uncommon in the pediatric age group, accounting for 2% of pediatric hepatic tumors, and are extremely rare in males. The etiology of HA and FNH has been correlated with the use of oral contraceptives. We report to the best of our knowledge the first series of patients treated with OLTx for HA and FNH (five cases). All these patients had lesions involving at least 90% of the hepatic parenchyma and all underwent major hepatic surgery before OLTx because of life threatening complications. One patient died in the immediate postoperative period following retransplantation for primary non-function of the first OLTx. Four out of five patients are currently alive from 4.1 to 9.6 years after OLTx. Our results justify the use of OLTx for symptomatic patients with HA and FNH who cannot be treated with conventional hepatic resections
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