128 research outputs found

    Evidence for a family of SO(8) gauged supergravity theories

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    In this note we discuss the classification of duality orbits of N = 8 gauged supergravity models. Using tensor classifiers, we show that there is a one-parameter family of inequivalent SO(8) gauged supergravity theories. We briefly discuss the couplings of such models and show that, although the maximally symmetric vacuum has the same quadratic spectrum, the supersymmetry transformations, the couplings and the scalar potential are parameter dependent. We also comment on the possible M-theory uplift and on the meaning of the parameter for the dual gauge theories.Comment: 5 pages, 2 figures. v2: improved presentation. References fixe

    Chaos from Symmetry: Navier Stokes equations, Beltrami fields and the Universal Classifying Crystallographic Group

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    In this report-article, the general setup to classify and construct Arnold-Beltrami Flows on three-dimensional torii, previously introduced by one of us, is further pursued. The idea of a Universal Classifying Group (UCG) is improved. In particular, we construct for the first time such group for the hexagonal lattice. Mastering the cubic and hexagonal instances, we can cover all cases. We upgrade Beltrami flows to a special type of periodic solutions of the NS equations, presenting the relation between the classification of these flows with the classification of contact structures. The recent developments in contact and symplectic geometry, considering singular contact structures, in the framework of b-manifolds, is also reviewed and we show that the choice of the critical surface for the b-deformation seems to be strongly related to its group-theoretical structures. This opens directions of investigation towards a classification of the critical surfaces or boundaries in terms of the UCG and subgroups. Furthermore, as a result of this research programme a complete set of MATHEMATICA Codes (for the cubic and hexagonal cases) have been produced that are able to construct Beltrami Flows with an arbitrarily large number of parameters and analyze their hidden symmetry structures. Indeed the main goal is the systematic organization of the parameter space into group irreps. The two Codes are a further result, being the unavoidable basis for further investigations. The presented exact solutions illustrate the new conceptions and ideas here discussed. The main message is: the more symmetric is the Beltrami Flow, the highest the probability of an on-set of chaotic trajectories. In various applications we need chaos on small scales and a more orderly motion on larger ones. Merging elementary chaotic solutions with large directional ordered flows is the target for future research.Comment: LaTeX source, 152 pages and 69 figures. arXiv admin note: substantial text overlap with arXiv:1501.0460

    Emerging Roles of Repetitive and Repeat-Containing RNA in Nuclear and Chromatin Organization and Gene Expression

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    Genomic repeats have been intensely studied as regulatory elements controlling gene transcription, splicing and genome architecture. Our understanding of the role of the repetitive RNA such as the RNA coming from genomic repeats, or repetitive sequences embedded in mRNA/lncRNAs, in nuclear and cellular functions is instead still limited. In this review we discuss evidence supporting the multifaceted roles of repetitive RNA and RNA binding proteins in nuclear organization, gene regulation, and in the formation of dynamic membrane-less aggregates. We hope that our review will further stimulate research in the consolidating field of repetitive RNA biology

    Fluorimetricex vivoquantification of protease debriding efficacy on natural substrate

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    Debridement is the process of removal of necrotic and infected tissue to clean a wound or burn and expedite healing. Proteases such as papain, bromelain and collagenase that promote debridement by degrading proteins in the dead tissue are in use today. However, the only method to measure debriding efficacy in vitro is the fluorescent monitoring of the digestion of an Artificial Wound Eschar (AWE) substrate. This AWE substrate contains a pellet of only three eschar matrix proteins collagen, elastin, and fibrin which do not account for the complexity and the composition of necrotic tissue. Here, we describe an ex vivo method using dry necrotic full thickness human skin and ortho-phthalaldehyde (OPA), a molecule commonly used for sensitive fluorimetric protein detection to monitor debridement activity. We advocate this simple yet sensitive approach to detect debridement efficacy that can readily be used commercially to benchmark products prior to in vivo testing. This article is protected by copyright. All rights reserved

    Condensation of vortices in the X-Y model in 3d: a disorder parameter

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    A disorder parameter is constructed which signals the condensation of vortices. The construction is tested by numerical simulations.Comment: 9 pages, 5 postscript figures, typset using REVTE

    Staple line reinforcement with nebulized cyanoacrylate glue in laparoscopic sleeve gastrectomy: A propensity score-matched study

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    Background: A dreaded complication of laparoscopic sleeve gastrectomy (LSG) is suture leak. The study aimed to assess the efficacy of the nebulized comonomer Glubran 2® (N-butyl-cyanoacrylate + metacrylosysolfolane) applied to the LSG staple line. Methods: A propensity-matched comparison analysis was conducted in 125 patients undergoing LSG between 2017 and 2019. Groups included those treated with Glubran® (group 1, n = 70) and those without Glubran® treatment (group 2, n = 55). Results: There were differences in the mean body mass index (44.4 vs 43 kg/m2; P < 0.05) between the groups. There was a non-significant increase in the operative time for group 1 compared with group 2 (97 ± 8 vs 93.8 ± 10.7 min; P = 0.07), with a greater amount of estimated blood loss (94.5 mL vs 87.8; P < 0.01). There were more severe complications in group 2 over group 1 cases (8 vs 0%; P < 0.05), although postoperative bleeding did not differ between the two groups (1.4 vs 5.4%). There were no postoperative leaks in group 1 patients, but there were two leaks in group 2 cases with an increased length of hospital stay in patients with a leak. Conclusion: Glubran® LSG support may reduce leak risk without increasing operating time

    Ageing with sacral nerve modulation for fecal incontinence: how many patients get benefit after more than 10 years?

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    Sacral nerve modulation (SNM) has represented a major advancement in the minimally invasive management of patients with fecal incontinence (FI). Although the success rate in the short-medium term has widely been demonstrated, the very long-term outcomes are poorly investigated. This study aims to assess the effectiveness of SNM in a cohort of patients with a follow-up longer than 10 years. Clinical records of patients submitted to SNM for FI in our tertiary referral colorectal Unit between 1998 and 2010 were retrospectively reviewed looking for status of the implantable pulse generator (IPG), follow-up duration, severity of FI by the St Marks' score and quality of life. 58 patients fulfilled the entry criteria and 36 (58%, median follow-up, 12 years) accepted to take part to the telephone interview, while 22 (38%) were lost to the follow-up. Nineteen patients had their IPG removed (Group A) while 17 (27%) had the SNM still active after a median follow-up of 13 years (Group B). In the group A, the median baseline St Marks' score was 13 and did not change after the IPG removal. In group B, the median baseline St Marks' score was 14, at last IPG substitution, it was of 7 and at the last follow-up dropped to 4. In the group A, the median SF-12 physical and mental scores did not change significantly while they improved significantly in group B. A progressive deterioration of the success rate of SNM with the time has been documented after a very long-term follow-up

    Tits-Satake projections of homogeneous special geometries

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    We organize the homogeneous special geometries, describing as well the couplings of D=6, 5, 4 and 3 supergravities with 8 supercharges, in a small number of universality classes. This relates manifolds on which similar types of dynamical solutions can exist. The mathematical ingredient is the Tits-Satake projection of real simple Lie algebras, which we extend to all solvable Lie algebras occurring in these homogeneous special geometries. Apart from some exotic cases all the other, 'very special', homogeneous manifolds can be grouped in seven universality classes. The organization of these classes, which capture the essential features of their basic dynamics, commutes with the r- and c-map. Different members are distinguished by different choices of the paint group, a notion discovered in the context of cosmic billiard dynamics of non maximally supersymmetric supergravities. We comment on the usefulness of this organization in universality classes both in relation with cosmic billiard dynamics and with configurations of branes and orbifolds defining special geometry backgrounds.Comment: 65 pages, LaTeX; v2: added reference; v3: small corrections, section 3.3 modifie

    Biotin-tagged fluorescent sensor to visualize "mobile' Zn2+ in cancer cells

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    A cancer cell-targeting fluorescent sensor has been developed to image mobile Zn2+ by introducing a biotin group. It shows a highly selective response to Zn2+ in vitro, no toxicity in cellulo and images 'mobile' Zn2+ specifically in cancer cells. We believe this probe has the potential to help improve our understanding of the role of Zn2+ in the processes of cancer initiation and development

    Critical points of the Black-Hole potential for homogeneous special geometries

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    We extend the analysis of N=2 extremal Black-Hole attractor equations to the case of special geometries based on homogeneous coset spaces. For non-BPS critical points (with non vanishing central charge) the (Bekenstein-Hawking) entropy formula is the same as for symmetric spaces, namely four times the square of the central charge evaluated at the critical point. For non homogeneous geometries the deviation from this formula is given in terms of geometrical data of special geometry in presence of a background symplectic charge vector.Comment: 17 pages, LaTeX fil
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