1,822 research outputs found

    Pheochromocytoma – clinical manifestations, diagnosis and current perioperative management

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    Pheochromocytoma is a neuroendocrine tumor characterized by the excessive production of catecholamines (epinephrine, norepinephrine, and dopamine). The diagnosis is suspected due to hypertensive paroxysms, associated with vegetative phenomena, due to the catecholaminergic hypersecretion. Diagnosis involves biochemical tests that reveal elevated levels of catecholamine metabolites (metanephrine and normetanephrine). Functional imaging, such as 123I-metaiodobenzylguanidine scintigraphy (123I-MIBG), has increased specificity in identifying the catecholamine-producing tumor and its metastases. The gold-standard treatment for patients with pheochromocytoma is represented by the surgical removal of the tumor. Before surgical resection, it is important to optimize blood pressure and intravascular volume in order to avoid negative hemodynamic events

    Use of Novel Antidiabetic Agents in Patients with Type\ua02 Diabetes and COVID-19: A Critical Review

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    Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). The latter is a pandemic that has the potential of developing into a severe illness manifesting as systemic inflammatory response syndrome, acute respiratory distress syndrome, multi-organ involvement and shock. In addition, advanced age and male sex and certain underlying health conditions, like type 2 diabetes mellitus (T2DM), predispose to a higher risk of greater COVID-19 severity and mortality. This calls for an urgent identification of antidiabetic agents associated with more favourable COVID-19 outcomes among patients with T2DM, as well as recognition of their potential underlying mechanisms. It is crucial that individuals with T2DM be kept under very stringent glycaemic control in order to avoid developing various cardiovascular, renal and metabolic complications associated with more severe forms of COVID-19 that lead to increased mortality. The use of novel antidiabetic agents dipeptidyl peptidase 4 inhibitors (DPP4i), sodium-glucose co-transporter 2 inhibitors (SGLT2i) and glucagon-like peptide 1 receptor agonists (GLP-1RAs) in subjects with T2DM may have beneficial effects on COVID-19 outcomes. However, relevant studies either show inconsistent results (DPP4i) or are still too few (SGLT2i and GLP-1RAs). Further research is therefore needed to assess the impact of these agents on COVID-19 outcomes

    Characterization of defect structures in nanocrystalline materials by X-ray line profile analysis

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    X-ray line profile analysis is a powerful alternative tool for determining dislocation densities, dislocation type, crystallite and subgrain size and size-distributions, and planar defects, especially the frequency of twin boundaries and stacking faults. The method is especially useful in the case of submicron grain size or nanocrystalline materials, where X-ray line broadening is a well pronounced effect, and the observation of defects with very large density is often not easy by transmission electron microscopy. The fundamentals of X-ray line broadening are summarized in terms of the different qualitative breadth methods, and the more sophisticated and more quantitative whole pattern fitting procedures. The efficiency and practical use of X-ray line profile analysis is shown by discussing its applications to metallic, ceramic, diamond-like and polymer nanomaterials

    Pheochromocytoma – clinical manifestations, diagnosis and current perioperative management

    Get PDF
    Pheochromocytoma is a neuroendocrine tumor characterized by the excessive production of catecholamines (epinephrine, norepinephrine, and dopamine). The diagnosis is suspected due to hypertensive paroxysms, associated with vegetative phenomena, due to the catecholaminergic hypersecretion. Diagnosis involves biochemical tests that reveal elevated levels of catecholamine metabolites (metanephrine and normetanephrine). Functional imaging, such as 123I-metaiodobenzylguanidine scintigraphy (123I-MIBG), has increased specificity in identifying the catecholamine-producing tumor and its metastases. The gold-standard treatment for patients with pheochromocytoma is represented by the surgical removal of the tumor. Before surgical resection, it is important to optimize blood pressure and intravascular volume in order to avoid negative hemodynamic events

    Nanocrystalline materials studied by powder diffraction line profile analysis

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    X-ray powder diffraction is a powerful tool for characterising the microstructure of crystalline materials in terms of size and strain. It is widely applied for nanocrystalline materials, especially since other methods, in particular electron microscopy is, on the one hand tedious and time consuming, on the other hand, due to the often metastable states of nanomaterials it might change their microstructures. It is attempted to overview the applications of microstructure characterization by powder diffraction on nanocrystalline metals, alloys, ceramics and carbon base materials. Whenever opportunity is given, the data provided by the X-ray method are compared and discussed together with results of electron microscopy. Since the topic is vast we do not try to cover the entire field

    First Results on In-Beam gamma Spectroscopy of Neutron-Rich Na and Mg Isotopes at REX-ISOLDE

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    After the successful commissioning of the radioactive beam experiment at ISOLDE (REX-ISOLDE) - an accelerator for exotic nuclei produced by ISOLDE - first physics experiments using these beams were performed. Initial experiments focused on the region of deformation in the vicinity of the neutron-rich Na and Mg isotopes. Preliminary results show the high potential and physics opportunities offered by the exotic isotope accelerator REX in conjunction with the modern Germanium gamma spectrometer MINIBALL.Comment: 7 pages, RNB6 conference contributio

    A Measurement of the Ds+ Lifetime

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    A high statistics measurement of the Ds+ lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis of the two decay modes, Ds+ -> phi(1020)pi+ and Ds+ -> \bar{K}*(892)0K+, used for the measurement. The measured lifetime is 507.4 +/- 5.5 (stat.) +/- 5.1 (syst.) fs using 8961 +/- 105 Ds+ -> phi(1020)pi+ and 4680 +/- 90 Ds+ -> \bar{K}*(892)0K+ decays. This is a significant improvement over the present world average.Comment: 5 pages, 3 figures, 2 tables, submitted to PR

    A High Statistics Measurement of the Lambdac+ Lifetime

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    A high statistics measurement of the Lambdac+ lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis technique with particular attention to the determination of the systematic uncertainty. The measured value of 204.6 +/- 3.4 (stat.) +/- 2.5 (syst.) fs from 8034 +/- 122 Lambdac -> pKpi decays represents a significant improvement over the present world average.Comment: Submitted to Physical Review Letter

    Feasibility studies of the time-like proton electromagnetic form factor measurements with PANDA at FAIR

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    The possibility of measuring the proton electromagnetic form factors in the time-like region at FAIR with the \PANDA detector is discussed. Detailed simulations on signal efficiency for the annihilation of pˉ+p\bar p +p into a lepton pair as well as for the most important background channels have been performed. It is shown that precision measurements of the differential cross section of the reaction pˉ+p→e++e−\bar p +p \to e^++ e^- can be obtained in a wide angular and kinematical range. The individual determination of the moduli of the electric and magnetic proton form factors will be possible up to a value of momentum transfer squared of q2≃14q^2\simeq 14 (GeV/c)2^2. The total pˉ+p→e++e−\bar p +p\to e^++e^- cross section will be measured up to q2≃28q^2\simeq 28 (GeV/c)2^2. The results obtained from simulated events are compared to the existing data. Sensitivity to the two photons exchange mechanism is also investigated.Comment: 12 pages, 4 tables, 8 figures Revised, added details on simulations, 4 tables, 9 figure
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