90 research outputs found

    The quantization of the symplectic groupoid of the standard Podles sphere

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    We give an explicit form of the symplectic groupoid that integrates the semiclassical standard Podles sphere. We show that Sheu's groupoid, whose convolution C*-algebra quantizes the sphere, appears as the groupoid of the Bohr-Sommerfeld leaves of a (singular) real polarization of the symplectic groupoid. By using a complex polarization we recover the convolution algebra on the space of polarized sections. We stress the role of the modular class in the definition of the scalar product in order to get the correct quantum space.Comment: 33 pages; minor correction

    α-Tocopheryl succinate promotes selective cell death induced by vitamin K3 in combination with ascorbate

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    BACKGROUND: A strategy to reduce the secondary effects of anti-cancer agents is to potentiate the therapeutic effect by their combination. A combination of vitamin K3 (VK3) and ascorbic acid (AA) exhibited an anti-cancer synergistic effect, associated with extracellular production of H2O2 that promoted cell death. METHODS: The redox-silent vitamin E analogue a-tocopheryl succinate (a-TOS) was used in combination with VK3 and AA to evaluate their effect on prostate cancer cells. RESULTS: Prostate cancer cells were sensitive to a-TOS and VK3 treatment, but resistant to AA upto 3.2mM. When combined, a synergistic effect was found for VK3\u2013AA, whereas a-TOS\u2013VK3 and a-TOS\u2013AA combination showed an antagonist and additive effect, respectively. However, sub-lethal doses of AA\u2013VK3 combination combined with a sub-toxic dose of a-TOS showed to induce efficient cell death that resembles autoschizis. Associated with this cell demise, lipid peroxidation, DNA damage, cytoskeleton alteration, lysosomal\u2013mitochondrial perturbation, and release of cytochrome c without caspase activation were observed. Inhibition of lysosomal proteases did not attenuate cell death induced by the combined agents. Furthermore, cell deaths by apoptosis and autoschizis were detected. CONCLUSION: These finding support the emerging idea that synergistic combinations of some agents can overcome toxicity and other side-effects associated with high doses of single drugs creating the opportunity for therapeutically relevant selectivity

    Association of MiR-126 with Soluble Mesothelin-Related Peptides, a Marker for Malignant Mesothelioma

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    BACKGROUND: Improved detection methods for diagnosis of malignant pleural mesothelioma (MPM) are essential for early and reliable detection as well as treatment. Since recent data point to abnormal levels of microRNAs (miRNAs) in tumors, we hypothesized that a profile of deregulated miRNAs may be a marker of MPM and that the levels of specific miRNAs may be used for monitoring its progress. METHODS AND RESULTS: miRNAs isolated from fresh-frozen biopsies of MPM patients were tested for the expression of 88 types of miRNA involved in cancerogenesis. Most of the tested miRNAs were downregulated in the malignant tissues compared with the normal tissues. Of eight significantly downregulated, three miRNAs were assayed in cancerous tissue and adjacent non-cancerous tissue sample pairs collected from 27 formalin-fixed, paraffin-embedded MPM tissues by quantitative RT-PCR. Among the miRNAs tested, only miR-126 significantly remained downregulated in the malignant tissues. Furthermore, the performance of the selected miR-126 as biomarker was evaluated in serum samples of asbestos-exposed subjects and MPM patients and compared with controls. MiR-126 was not affected by asbestos exposure, whereas it was found strongly associated with VEGF serum levels. Levels of miR-126 in serum, and its levels in patients' serum in association with a specific marker of MPM, SMRPs, correlate with subjects at high risk to develop MPM. CONCLUSIONS AND SIGNIFICANCE: We propose miR-126, in association with SMRPs, as a marker for early detection of MPM. The identification of tumor biomarkers used alone or, in particular, in combination could greatly facilitate the surveillance procedure for cohorts of subjects exposed to asbestos

    [Treatment of electrolyte disorders by hemodialysis]

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    Electrolyte disorders may constitute a life-threatening emergency. Sometimes they can be treated with medical therapy but there are cases where emergency dialysis will be necessary. An important role is played by the dialysate (including different concentrations of electrolytes), which removes uremic toxins and balances the electrolyte disorders in patients with end-stage renal disease. The choice of dialysate is also important for control of the patient's vital functions during the dialysis session and in the period between sessions. Sodium is strongly related to weight gain between dialysis sessions and its concentration causes fluid overload or, on the contrary, hypotension. The choice of the buffer takes into account any possible bicarbonate- or acetate-related systemic effects. Potassium is very important for heart contraction and its fast removal could be associated with cardiac arrhythmias. The role of magnesium is still controversial. Calcium is related to hemodynamic stability, mineral bone disease and also cardiac arrhythmias. A correctly balanced dialysate is important to prevent and reduce intradialytic and interdialytic complications. The dialysate should be tailored to the needs of the individual patient

    Successful pregnancy in a uremic patient treated with single needle hemodialysis

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    Background: Pregnancy is uncommon in patients on maintenance hemodialysis (HD) and it carries a high risk of fetal and maternal complications. Several reports have shown that application of an intensive dialysis regimen is associated with improved infant survival and better clinical conditions of the mother. Methods: We report the case of a 35-year-old black woman with a prosthesic cardiac valve who was treated daily with single needle HD because of difficult vascular access. Result: A healthy full-term female infant with a normal birth weight was electively delivered at 37 weeks. We did not register any complications during or after pregnancy. Conclusion: In our experience, single needle HD is able to provide the patient with adequate depuration during pregnancy, the delivery of a full-term healthy infant, and preservation of the arterial-venous fistula from twice-daily vein puncture

    Successful pregnancy in a uremic patient treated with single needle hemodialysis

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    Background: Pregnancy is uncommon in patients on maintenance hemodialysis (HD) and it carries a high risk of fetal and maternal complications. Several reports have shown that application of an intensive dialysis regimen is associated with improved infant survival and better clinical conditions of the mother. Methods: We report the case of a 35-year-old black woman with a prosthesic cardiac valve who was treated daily with single needle HD because of difficult vascular access. Result: A healthy full-term female infant with a normal birth weight was electively delivered at 37 weeks. We did not register any complications during or after pregnancy. Conclusion: In our experience, single needle HD is able to provide the patient with adequate depuration during pregnancy, the delivery of a full-term healthy infant, and preservation of the arterial-venous fistula from twice-daily vein puncture

    Statistical symmetries of the Lundgren-Monin-Novikov hierarchy

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    It was shown by Oberlack and Rosteck [Discr. Cont. Dyn. Sys. S, 3, 451 2010] that the infinite set of multipoint correlation (MPC) equations of turbulence admits a considerable extended set of Lie point symmetries compared to the Galilean group, which is implied by the original set of equations of fluid mechanics. Specifically, a new scaling group and an infinite set of translational groups of all multipoint correlation tensors have been discovered. These new statistical groups have important consequences for our understanding of turbulent scaling laws as they are essential ingredients of, e.g., the logarithmic law of the wall and other scaling laws, which in turn are exact solutions of the MPC equations. In this paper we first show that the infinite set of translational groups of all multipoint correlation tensors corresponds to an infinite dimensional set of translations under which the Lundgren-Monin-Novikov (LMN) hierarchy of equations for the probability density functions (PDF) are left invariant. Second, we derive a symmetry for the LMN hierarchy which is analogous to the scaling group of the MPC equations. Most importantly, we show that this symmetry is a measure of the intermittency of the velocity signal and the transformed functions represent PDFs of an intermittent (i.e., turbulent or nonturbulent) flow. Interesting enough, the positivity of the PDF puts a constraint on the group parameters of both shape and intermittency symmetry, leading to two conclusions. First, the latter symmetries may no longer be Lie group as under certain conditions group properties are violated, but still they are symmetries of the LMN equations. Second, as the latter two symmetries in its MPC versions are ingredients of many scaling laws such as the log law, the above constraints implicitly put weak conditions on the scaling parameter such as von Karman constant. as they are functions of the group parameters. Finally, let us note that these kind of statistical symmetries are of much more general type, i.e., not limited to MPC or PDF equations emerging from Navier-Stokes, but instead they are admitted by other nonlinear partial differential equations like, for example, the Burgers equation when in conservative form and if the nonlinearity is quadratic
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