115 research outputs found

    Unification of Gauge and Gravity Chern-Simons Theories in 3-D Space time

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    Chamseddine and Mukhanov showed that gravity and gauge theories could be unified in one geometric construction provided that a metricity condition is imposed on the vielbein. In this paper we are going to show that by enlarging the gauge group we are able to unify Chern-Simons gauge theory and Chern-Simons gravity in 3-D space-time. Such unification leads to the quantization of the coefficients for both Chern-Simons terms for compact groups but not for non-compact groups. Moreover, it leads to a topological invariant quantity of the 3 dimensional space-time manifold on which they are defined

    Small Bowel Tumors: Clinical Presentation, Prognosis, and Outcome in 33 Patients in a Tertiary Care Center

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    Introduction. Small bowel cancers are rare. Accumulation of data regarding their clinical presentation, pathologic features, prognostic factors, treatment modalities, and outcome is difficult. Methods. This is a retrospective study of the medical records of 33 patients with small bowel cancers treated at the American University of Beirut-Medical Center over a 20-year period. Results. The study included 25 males (76%) and 8 females (24%). Median age at presentation was 56 years. Most common symptoms were abdominal pain (66.7%) and weight loss (57.6%). Thirteen patients presented with abdominal emergencies (39.3%). Lymphoma was the most common malignant tumor (36.4%), followed by adenocarcinoma (33.3%), leiomyosarcoma (15.2%), gastrointestinal stromal tumors (12.1%), and neuroendocrine tumors (3.0%). Tumors were located in the duodenum in 30% of patients, jejunum in 33%, and ileum in 36%. Resectability rate was 72.7% and curative R0 resection was achieved in 54.1% (13/24) of patients. 5-year survival of the 33 patients was 24.2%. Conclusion. Small bowel cancers are difficult to diagnose because of the nonspecific symptoms. Most patients present with advanced disease and have poor prognosis. Adenocarcinoma and duodenal location have the worst 5-year survival in contrast to stromal tumors and those with ileal location which have the best survival

    Infinitesimals without Logic

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    We introduce the ring of Fermat reals, an extension of the real field containing nilpotent infinitesimals. The construction takes inspiration from Smooth Infinitesimal Analysis (SIA), but provides a powerful theory of actual infinitesimals without any need of a background in mathematical logic. In particular, on the contrary with respect to SIA, which admits models only in intuitionistic logic, the theory of Fermat reals is consistent with classical logic. We face the problem to decide if the product of powers of nilpotent infinitesimals is zero or not, the identity principle for polynomials, the definition and properties of the total order relation. The construction is highly constructive, and every Fermat real admits a clear and order preserving geometrical representation. Using nilpotent infinitesimals, every smooth functions becomes a polynomial because in Taylor's formulas the rest is now zero. Finally, we present several applications to informal classical calculations used in Physics: now all these calculations become rigorous and, at the same time, formally equal to the informal ones. In particular, an interesting rigorous deduction of the wave equation is given, that clarifies how to formalize the approximations tied with Hook's law using this language of nilpotent infinitesimals.Comment: The first part of the preprint is taken directly form arXiv:0907.1872 The second part is new and contains a list of example

    Non-Hodgkin's lymphoma in a woman with adult-onset Still's disease: a case report

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    INTRODUCTION: Adult onset Still's disease is a chronic multisystemic inflammatory disorder characterized by high spiking fever, polyarthralgia and rash. Lymphadenopathy is a prominent feature of adult onset Still's disease and is seen in about 65% of patients. Searching the medical literature using the MEDLINE database from January 1966 through November 2007 we could only find two reported cases of adult onset Still's disease that had progressed to lymphoma. CASE PRESENTATION: We describe a woman who was diagnosed with adult onset Still's disease and developed lymphoma 10 months after the onset of her symptoms. She initially presented with fever and arthritis of the knees, ankles and shoulders, along with a nonpruritic skin rash, myalgia and weight loss. On physical examination she was found to have several enlarged anterior cervical lymph nodes and left posterior auricular lymph nodes all of which were non-tender, immobile and rubbery. Excisional biopsy of the cervical lymph nodes was negative for malignancy. Bone marrow biopsy was also negative for malignancy. She was treated with prednisone. She remained in good health until she presented 10 months later with low back pain, dyspnea and weight loss. Work up revealed malignant lymphoma. She was treated with chemotherapy and was doing well until she presented with abdominal pain. Work up revealed a cirrhotic liver and ascites. She then passed away from hepatorenal syndrome 13 years after the diagnosis of lymphoma. To our knowledge, this is the third reported case of such an occurrence. CONCLUSION: Although the association between adult onset Still's disease and lymphoma has been rarely reported, careful screening for this malignancy in patients suspected to have adult onset Still's disease is warranted

    Role of Sterylglucosidase 1 (Sgl1) on the pathogenicity of Cryptococcus neoformans: Potential applications for vaccine development

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    Cryptococcosis caused by C. neoformans and C. gattii affects a large population and is a cause of significant morbidity and mortality. Despite its public health burden, there are currently no vaccines against cryptococcosis and new strategies against such infections are needed. In this study, we demonstrate that C. neoformans has the biochemical ability to metabolize sterylglucosides (SGs), a class of immunomodulatory glycolipids. Genetic manipulations that eliminate cryptococccal sterylglucosidase lead to the accumulation of SGs and generate a mutant strain (Îsgl1) that is non-pathogenic in the mouse models of cryptococcosis. Interestingly, this mutant strain acts as a vaccine strain and protects mice against cryptococcosis following infection with C. neoformans or C. gattii. The immunity induced by the Îsgl1 strain is not CD4+ T-cells dependent. Immunocompromised mice, which lack CD4+ T-cells, are able to control the infection by Îsgl1 and acquire immunity against the challenge by wild-type C. neoformans following vaccination with the Îsgl1 strain. These findings are particularly important in the context of HIV/AIDS immune deficiency and suggest that the Îsgl1 strain might provide a potential vaccination strategy against cryptococcosis

    Mechanisms controlling anaemia in Trypanosoma congolense infected mice.

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    Trypanosoma congolense are extracellular protozoan parasites of the blood stream of artiodactyls and are one of the main constraints on cattle production in Africa. In cattle, anaemia is the key feature of disease and persists after parasitaemia has declined to low or undetectable levels, but treatment to clear the parasites usually resolves the anaemia. The progress of anaemia after Trypanosoma congolense infection was followed in three mouse strains. Anaemia developed rapidly in all three strains until the peak of the first wave of parasitaemia. This was followed by a second phase, characterized by slower progress to severe anaemia in C57BL/6, by slow recovery in surviving A/J and a rapid recovery in BALB/c. There was no association between parasitaemia and severity of anaemia. Furthermore, functional T lymphocytes are not required for the induction of anaemia, since suppression of T cell activity with Cyclosporin A had neither an effect on the course of infection nor on anaemia. Expression of genes involved in erythropoiesis and iron metabolism was followed in spleen, liver and kidney tissues in the three strains of mice using microarrays. There was no evidence for a response to erythropoietin, consistent with anaemia of chronic disease, which is erythropoietin insensitive. However, the expression of transcription factors and genes involved in erythropoiesis and haemolysis did correlate with the expression of the inflammatory cytokines Il6 and Ifng. The innate immune response appears to be the major contributor to the inflammation associated with anaemia since suppression of T cells with CsA had no observable effect. Several transcription factors regulating haematopoiesis, Tal1, Gata1, Zfpm1 and Klf1 were expressed at consistently lower levels in C57BL/6 mice suggesting that these mice have a lower haematopoietic capacity and therefore less ability to recover from haemolysis induced anaemia after infection

    Peri-ampullary mixed acinar-endocrine carcinoma

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    Mixed acinar-endocrine carcinomas (MAEC) are rare tumors of the pancreas. We present the case of a patient with periampullary tumor that presented with painless jaundice and after investigation was found to have MAEC. He underwent pancreaticoduo-dunectomy with tumor free margins and negative lymph nodes. The patient presented with local recurrence and liver metastasis after 1 year and is on chemotherapy with stable lesions 30 months after the diagnosis
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