130 research outputs found

    On the canonical divisor of smooth toroidal compactifications

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    In this paper, we show that the canonical divisor of a smooth toroidal compactification of a complex hyperbolic manifold must be nef if the dimension is greater or equal to three. Moreover, if n3n\geq 3 we show that the numerical dimension of the canonical divisor of a smooth nn-dimensional compactification is always bigger or equal to n1n-1. We also show that up to a finite \'etale cover all such compactifications have ample canonical class, therefore refining a classical theorem of Mumford and Tai. Finally, we improve in all dimensions n3n\geq 3 the cusp count for finite volume complex hyperbolic manifolds given in [DD15a].Comment: Title shortened to match published versio

    Exceptional collections and the bicanonical map of Keum's fake projective planes

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    On Seshadri constants of varieties with large fundamental group

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    Let XX be a smooth variety and let LL be an ample line bundle on XX. If π1alg(X)\pi^{alg}_{1}(X) is large, we show that the Seshadri constant ϵ(pL)\epsilon(p^{*}L) can be made arbitrarily large by passing to a finite \'etale cover p:XXp:X'\rightarrow X. This result answers affirmatively a conjecture of J.-M. Hwang. Moreover, we prove an analogous result when π1(X)\pi_{1}(X) is large and residually finite. Finally, under the same topological assumptions, we appropriately generalize these results to the case of big and nef line bundles. More precisely, given a big and nef line bundle LL on XX and a positive number N>0N>0, we show that there exists a finite \'etale cover p:XXp: X'\rightarrow X such that the Seshadri constant ϵ(pL;x)N\epsilon(p^{*}L; x)\geq N for any xpB+(L)=B+(pL)x\notin p^{*}\textbf{B}_{+}(L)=\textbf{B}_{+}(p^{*}L), where B+(L)\textbf{B}_{+}(L) is the augmented base locus of LL

    Moving Seshadri constants, and coverings of varieties of maximal Albanese dimension

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    Let XX be a smooth projective complex variety of maximal Albanese dimension, and let LXL \to X be a big line bundle. We prove that the moving Seshadri constants of the pull-backs of LL to suitable finite abelian \'etale covers of XX are arbitrarily large. As an application, given any integer k1k\geq 1, there exists an abelian \'etale cover p ⁣:XXp\colon X' \to X such that the adjoint system KX+pL\big|K_{X'} + p^*L \big| separates kk-jets away from the augmented base locus of pLp^*L, and the exceptional locus of the pull-back of the Albanese map of XX under pp

    Effect of chicken bone extracts on metabolic and mitochondrial functions of K562 cell line

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    Background: Tetracyclines’ use in intensive animal farming has raised some concerns regarding the biosafety for humans. Increasing evidences have revealed the presence of these drugs in processed animal by-products, such as bone, throughout the food chain. A potential off-target of tetracyclines is the bacterial-like mitochondrial translational machinery, thereby causing proteostatic alterations in mitochondrial DNA-encoded components of the oxidative phosphorylation system. Methods: The Seahorse methodology, confocal microscopy imaging of mitochondrial potential and reactive oxygen species, and q-RT-PCR analysis of the expression of genes involved in mitochondrial biogenesis and mitophagy were carried out on human lymphoblast derived K562 cell line challenged with bone powder derived from chicken treated with or without oxytetracycline and pure oxytetracycline. Results: A complex dose-dependent profile was attained with a low dosage of bone powder extracts causing a metabolic adaptation hallmarked by stimulation of the mitochondrial respiration and enhanced expression of mitochondriogenic factors in particular in cells challenged with oxytetracycline-free bone extract. Conversely, a higher dosage of bone powder extracts, regardless of their source, caused a progressive inhibition of mitochondrial respiration and glycolysis, ultimately leading to cell death. No significant effects of the pure oxytetracycline were observed. Conclusion: Bone powder, regardless of chicken treatment, contains and releases factors/chemicals responsible for the observed effects on energy metabolism. Quantitative differential effects appear to depend on biochemical alterations in the bone matrix caused by antibiotics rather than antibiotics themselves

    The Ricci flow on noncommutative two-tori

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    In this paper we construct a version of Ricci flow for noncommutative 2-tori, based on a spectral formulation in terms of the eigenvalues and eigenfunction of the Laplacian and recent results on the Gauss-Bonnet theorem for noncommutative tori.Comment: 18 pages, LaTe

    Molecular analysis of the apoptotic effects of BPA in acute myeloid leukemia cells

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    <p>Abstract</p> <p>Background:</p> <p>BPA (bisphenol A or 2,2-bis(4-hydroxy-phenol)propane) is present in the manufacture of polycarbonate plastic and epoxy resins, which can be used in impact-resistant safety equipment and baby bottles, as protective coatings inside metal food containers, and as composites and sealants in dentistry. Recently, attention has focused on the estrogen-like and carcinogenic adverse effects of BPA. Thus, it is necessary to investigate the cytotoxicity and apoptosis-inducing activity of this compound.</p> <p>Methods:</p> <p>Cell cycle, apoptosis and differentiation analyses; western blots.</p> <p>Results:</p> <p>BPA is able to induce cell cycle arrest and apoptosis in three different acute myeloid leukemias. Although some granulocytic differentiation concomitantly occurred in NB4 cells upon BPA treatment, the major action was the induction of apoptosis. BPA mediated apoptosis was caspase dependent and occurred by activation of extrinsic and intrinsic cell death pathways modulating both FAS and TRAIL and by inducing BAD phosphorylation in NB4 cells. Finally, also non genomic actions such as the early decrease of both ERK and AKT phosphorylation were induced by BPA thus indicating that a complex intersection of regulations occur for the apoptotic action of BPA.</p> <p>Conclusion:</p> <p>BPA is able to induce apoptosis in leukemia cells via caspase activation and involvement of both intrinsic and extrinsic pathways of apoptosis.</p

    Perinatal care in SARS-CoV-2 infected women: the lesson learnt from a national prospective cohort study during the pandemic in Italy

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    Background: Despite the growing importance given to ensuring high-quality childbirth, perinatal good practices have been rapidly disrupted by SARS-CoV-2 pandemic. This study aimed at describing the childbirth care provided to infected women during two years of COVID-19 emergency in Italy. Methods: A prospective cohort study enrolling all women who gave birth with a confirmed SARS-CoV-2 infection within 7 days from hospital admission in the 218 maternity units active in Italy during the periods February 25, 2020-June 30, 2021, and January 1-May 31, 2022. Perinatal care was assessed by evaluating the prevalence of the following indicators during the pandemic: presence of a labour companion; skin-to-skin; no mother-child separation at birth; rooming-in; breastfeeding. Logistic regression models including women' socio-demographic, obstetric and medical characteristics, were used to assess the association between the adherence to perinatal practices and different pandemic phases. Results: During the study period, 5,360 SARS-CoV-2 positive women were enrolled. Overall, among those who had a vaginal delivery (n = 3,574; 66.8%), 37.5% had a labour companion, 70.5% of newborns were not separated from their mothers at birth, 88.1% were roomed-in, and 88.0% breastfed. These four indicators showed similar variations in the study period with a negative peak between September 2020 and January 2021 and a gradual increase during the Alpha and Omicron waves. Skin-to-skin (mean value 66.2%) had its lowest level at the beginning of the pandemic and gradually increased throughout the study period. Among women who had a caesarean section (n = 1,777; 33.2%), all the indicators showed notably worse outcomes with similar variations in the study period. Multiple logistic regression analyses confirm the observed variations during the pandemic and show a lower adherence to good practices in southern regions and in maternity units with a higher annual number of births. Conclusions: Despite the rising trend in the studied indicators, we observed concerning substandard childbirth care during the SARS-CoV-2 pandemic. Continued efforts are necessary to underscore the significance of the experience of care as a vital component in enhancing the quality of family-centred care policies

    Intra-oral orthosis vs amitriptyline in chronic tension-type headache: a clinical and laser evoked potentials study

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    BACKGROUND: In the present study, we examined clinical and laser-evoked potentials (LEP) features in two groups of chronic tension-type headache (CTTH) patients treated with two different approaches: intra-oral appliance of prosthesis, aiming to reduce muscular tenderness, and 10 mg daily amitriptyline. METHODS: Eighteen patients with diagnosed CTTH participated in this open label, controlled study. A baseline evaluation was performed for clinical features, Total Tenderness Score (TTS) and a topographic analysis of LEPs obtained manually and the pericranial points stimulation in all patients vs. healthy subjects. Thereafter, patients were randomly assigned to a two-month treatment by either amitriptyline or intra-oral appliance. RESULTS AND DISCUSSION: Both the intra-oral appliance and amitriptyline significantly reduced headache frequency. The TTS was significantly reduced in the group treated with the appliance. The amplitude of P2 response elicited by stimulation of pericranial zones showed a reduction after amitriptyline treatment. Both therapies were effective in reducing headache severity, the appliance with a prevalent action on the pericranial muscular tenderness, amitriptyline reducing the activity of the central cortical structures subtending pain elaboration CONCLUSION: The results of this study may suggest that in CTTH both the interventions at the peripheral and central levels improve the outcome of headache
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