128 research outputs found
Evidence for a family of SO(8) gauged supergravity theories
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
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
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
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
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
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?
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
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
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
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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