83 research outputs found

    Abelian oil and water dynamics does not have an absorbing-state phase transition

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    The oil and water model is an interacting particle system with two types of particles and a dynamics that conserves the number of particles, which belongs to the so-called class of Abelian networks. Widely studied processes in this class are sandpiles models and activated random walks, which are known (at least for some choice of the underlying graph) to undergo an absorbing-state phase transition. This phase transition characterizes the existence of two regimes, depending on the particle density: a regime of fixation at low densities, where the dynamics converges towards an absorbing state and each particle jumps only finitely many times, and a regime of activity at large densities, where particles jump infinitely often and activity is sustained indefinitely. In this work we show that the oil and water model is substantially different than sandpiles models and activated random walks, in the sense that it does not undergo an absorbing-state phase transition and is in the regime of fixation at all densities. Our result works in great generality: for any graph that is vertex transitive and for a large class of initial configurations

    The activation of M2 muscarinic receptor inhibits cell growth and survival in human epithelial ovarian carcinoma

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    Ovarian cancer is the fifth leading cause of cancer-related deaths in females. Many ovarian tumor cell lines express muscarinic receptors (mAChRs), and their expression is correlated with reduced survival of patients. We have characterized the expression of mAChRs in two human ovarian carcinoma cell lines (SKOV-3, TOV-21G) and two immortalized ovarian surface epithelium cell lines (iOSE-120, iOSE-398). Among the five subtypes of mAChRs (M1–M5 receptors), we focused our attention on the M2 receptor, which is involved in the inhibition of tumor cell proliferation. Western blot analysis and real-time PCR analyses indicated that the levels of M2 are statistically downregulated in cancer cells. Therefore, we investigated the effect of arecaidine propargyl ester hydrobromide (APE), a preferential M2 agonist, on cell growth and survival. APE treatment decreased cell number in a dose and time-dependent manner by decreasing cell proliferation and increasing cell death. FACS and immunocytochemistry analysis have also demonstrated the ability of APE to accumulate the cells in G2/M phase of the cell cycle and to increase the percentage of abnormal mitosis. The higher level of M2 receptors in the iOSE cells rendered these cells more sensitive to APE treatment than cancer cells. The data here reported suggest that M2 has a negative role in cell growth/survival of ovarian cell lines, and its downregulation may favor tumor progression

    Bone GLA protein in predialysis chronic renal failure. Effects of 1,25(OH)2D3 administration in a long-term follow-up.

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    Bone GLA protein in predialysis chronic renal failure. Effects of 1,25(OH)2D3 administration in a long-term follow-up. Serum bone GLA protein (BGP) was measured by radioimmunoassay in 42 patients (age, 47.5 ± 16.6 years; serum creatinine, 4.32 ± 1.9 mg/dl) with predialysis chronic renal failure (CRF). Nineteen patients were studied within a short period of time, while 23 were followed with repeated measurements of serum BGP, creatinine, iPTH, and alkaline phosphatase (AP) for a mean period of 17.1 ± 8.1 months. Eleven of these patients were treated with 1,25(OH)2D3 for a mean of 16.8 ± 6.4 months. In 23 patients at various stages of CRF, a transiliac bone biopsy was performed for histomorphometric evaluation. In the untreated patients, serum BGP was higher than normal and showed a positive correlation with creatinine levels (P < 0.001). Serum BGP was also positively correlated with iPTH, AP, serum phosphate, active resorption surface, active osteoblastic surface, osteoid surface, and volume. EHiring treatment with 1,25(OH)2D3, BGP, iPTH, and AP were significantly lower than in the untreated patients. The reduction in iPTH and BGP was proportional, while BGP and AP no longer correlated. Repeated measurements of BGP during the long-term follow-up showed a progressive rise in the untreated patients and a downward course of BGP levels during treatment. In conclusion, serum BGP increases progressively in CRF, rising with advancing renal damage in close correlation with iPTH, AP, and the severity of renal osteodystrophy. Treatment with 1,25(OH)2D3 causes a parallel decline in BGP and iPTH levels and dissociation between BGP and AP can be observed. Compared to AP, BGP seems to be a more reliable index of secondary hyperparathyroidism and potentially more useful in the long-term monitoring of treatment with 1,25(OH)2D3.
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