409 research outputs found
Velocity Distribution of Topological Defects in Phase-Ordering Systems
The distribution of interface (domain-wall) velocities in a
phase-ordering system is considered. Heuristic scaling arguments based on the
disappearance of small domains lead to a power-law tail,
for large v, in the distribution of . The exponent p is
given by , where d is the space dimension and 1/z is the growth
exponent, i.e. z=2 for nonconserved (model A) dynamics and z=3 for the
conserved case (model B). The nonconserved result is exemplified by an
approximate calculation of the full distribution using a gaussian closure
scheme. The heuristic arguments are readily generalized to conserved case
(model B). The nonconserved result is exemplified by an approximate calculation
of the full distribution using a gaussian closure scheme. The heuristic
arguments are readily generalized to systems described by a vector order
parameter.Comment: 5 pages, Revtex, no figures, minor revisions and updates, to appear
in Physical Review E (May 1, 1997
Non-equilibrium Condensation Process in a Holographic Superconductor
We study the non-equilibrium condensation process in a holographic
superconductor. When the temperature T is smaller than a critical temperature
T_c, there are two black hole solutions, the Reissner-Nordstrom-AdS black hole
and a black hole with a scalar hair. In the boundary theory, they can be
regarded as the supercooled normal phase and the superconducting phase,
respectively. We consider perturbations on supercooled Reissner-Nordstrom-AdS
black holes and study their non-linear time evolution to know about physical
phenomena associated with rapidly-cooled superconductors. We find that, for
T<T_c, the initial perturbations grow exponentially and, eventually, spacetimes
approach the hairy black holes. We also clarify how the relaxation process from
a far-from-equilibrium state proceeds in the boundary theory by observing the
time dependence of the superconducting order parameter. Finally, we study the
time evolution of event and apparent horizons and discuss their correspondence
with the entropy of the boundary theory. Our result gives a first step toward
the holographic understanding of the non-equilibrium process in
superconductors.Comment: 20 pages, 7 figure
Resezioni polmonari limitate “intenzionali” versus lobectomie nel trattamento dei tumori polmonari periferici non microcitomi allo stadio IA
Scopo del presente studio è valutare, attraverso l’analisi retrospettiva della nostra casistica e la revisione della letteratura, se le resezioni polmonari limitate siano equivalenti alla lobectomia nel trattamento dei tumori polmonari non microcitomi (NSCLC) periferici allo stadio IA (T1N0M0), in termini di radicalità oncologica, sopravvivenza e tasso di recidive locali, regionali e sistemiche.Viene inoltre preso in considerazione l’impatto delle resezioni limitate, rispetto alle resezioni lobari, sulla funzionalità polmonare postoperatoria.
Pazienti e metodi. Abbiamo analizzato una serie consecutiva di 36 pazienti, 28 uomini e 8 donne, di età compresa fra 61 e 81 anni (media 73 anni), sottoposti ad intervento chirurgico, nel periodo compreso fra gennaio 2000 e dicembre 2003, per NSCLC periferici T1N0M0; sono state effettuate 11 resezioni limitate e 25 lobectomie. Sono state analizzate comparativamente sopravvivenza e recidive (follow-up 3-5 anni), nonché le prove di funzionalità respiratoria ad un anno dall’intervento.
Risultati. La sopravvivenza a 3 e 5 anni è stata pari all’88% ed all’82% nel gruppo dei pazienti sottoposti a resezioni limitate, al 93% e all’88% nel gruppo dei pazienti sottoposti a lobectomia. Si è verificata una recidiva locale (9%) nel primo gruppo, una (4%) nel secondo. Ad un anno dall’intervento si sono osservati un moderato decremento del volume espiratorio
forzato in 1 secondo (FEV1) e della capacità di diffusione per monossido di carbonio (DLCO) nei pazienti sottoposti a resezione lobare, e un sostanziale mantenimento dei parametri funzionali preoperatori, eccezion fatta per la
DLCO, nei pazienti sottoposti a resezione limitata.
Conclusioni. La nostra circoscritta esperienza, in accordo con le tendenze attuali della letteratura, indica che l’intervento di resezione polmonare
limitata, in pazienti selezionati, con NSCLC periferici allo stadio IA, rappresenta una valida alternativa alla lobectomia in termini di sopravvivenza e
tasso di recidiva, determinando altresì un minor decremento della funzionalità polmonare postoperatoria. La segmentectomia può essere dunque considerata,
in tali casi, procedura chirurgica di scelta, anche in pazienti in grado di tollerare una resezione maggior
Scaling Model of Annihilation-Diffusion Kinetics for Charged Particles with Long-Range Interactions
We propose the general scaling model for the diffusio n-annihilation reaction
with long-range power-law i
nteractions. The presented scaling arguments lead to the finding of three
different regimes, dep ending on the space dimensionality d and the long-range
force power e xponent n. The obtained kinetic phase diagram agrees well with
existing simulation data and approximate theoretical results.Comment: RevTEX, 7 pages, no figures, accepted to Physical Review
PROTECTIVE EFFECTS OF ANTHOCYANINS FROM BLACKBERRY IN A RAT MODEL OF ACUTE LUNG INFLAMMATION.
Anthocyanins are a group of naturally occuring phenolic compounds related to the coloring of plants, flowers and fruits. These pigments are important as quality indicators, as chemotaxonomic markers and for their antioxidant activities. Here, we have investigated the therapeutic efficacy of anthocyanins contained in blackberry extract (cyanidin-3-O-glucoside represents about 80% of the total anthocyanin contents) in an experimental model of lung inflammation induced by carrageenan in rats. Injection of carrageenan into the pleural cavity elicited an acute inflammatory response characterized by fluid accumulation which contained a large number of neutrophils as well as an infiltration of polymorphonuclear leukocytes in lung tissues and subsequent lipid peroxidation, and increased production of nitrite/nitrate (NOx) and prostaglandin E2 (PGE2). All parameters of inflammation were attenuated in a dose-dependent manner by anthocyanins (10, 30 mg kg-1 30 min before carrageenan). Furthermore, carrageenan induced an upregulation of the adhesion molecule ICAM-1, nitrotyrosine and poly (ADP-ribose) synthetase (PARS) as determined by immunohistochemical analysis of lung tissues. The degree of staining was lowered by anthocyanins treatment. Thus, the anthocyanins contained in the blackberry extract exert multiple protective effects in carrageenan-induced pleurisy
Self-Consistent Model of Annihilation-Diffusion Reaction with Long-Range Interactions
We introduce coarse-grained hydrodynamic equations of motion for
diffusion-annihilation system with a power-law long-range interaction. By
taking into account fluctuations of the conserved order parameter - charge
density - we derive an analytically solvable approximation for the nonconserved
order parameter - total particle density. Asymptotic solutions are obtained for
the case of random Gaussian initial conditions and for system dimensionality . Large-t, intermediate-t and small-t asymptotics were calculated and
compared with existing scaling theories, exact results and simulation data.Comment: 22 pages, RevTEX, 1 PostScript figur
Growth Laws for Phase Ordering
We determine the characteristic length scale, , in phase ordering
kinetics for both scalar and vector fields, with either short- or long-range
interactions, and with or without conservation laws. We obtain
consistently by comparing the global rate of energy change to the energy
dissipation from the local evolution of the order parameter. We derive growth
laws for O(n) models, and our results can be applied to other systems with
similar defect structures.Comment: 12 pages, LaTeX, second tr
Estimation of vortex density after superconducting film quench
This paper addresses the problem of vortex formation during a rapid quench in
a superconducting film. It builds on previous work showing that in a local
gauge theory there are two distinct mechanisms of defect formation, based on
fluctuations of the scalar and gauge fields, respectively. We show how vortex
formation in a thin film differs from the fully two-dimensional case, on which
most theoretical studies have focused. We discuss ways of testing theoretical
predictions in superconductor experiments and analyse the results of recent
experiments in this light.Comment: 7 pages, no figure
The Use of Biofluid Markers to Evaluate the Consequences of Sport-Related Subconcussive Head Impact Exposure : A Scoping Review
Funding Information: This review was supported by the University of Stirling (no grant number applies). L.W. also received support as part of Framework 7 programme of the European Union (CENTER-TBI, Grant number: 602150–2). S.M. received research support from the Italian Ministry of Health (GR-2013–02354960).Peer reviewe
Machine learning to improve interpretability of clinical, radiological and panel-based genomic data of glioma grade 4 patients undergoing surgical resection
Background: Glioma grade 4 (GG4) tumors, including astrocytoma IDH-mutant grade 4 and the astrocytoma IDH wt are the most common and aggressive primary tumors of the central nervous system. Surgery followed by Stupp protocol still remains the first-line treatment in GG4 tumors. Although Stupp combination can prolong survival, prognosis of treated adult patients with GG4 still remains unfavorable. The introduction of innovative multi-parametric prognostic models may allow refinement of prognosis of these patients. Here, Machine Learning (ML) was applied to investigate the contribution in predicting overall survival (OS) of different available data (e.g. clinical data, radiological data, or panel-based sequencing data such as presence of somatic mutations and amplification) in a mono-institutional GG4 cohort. Methods: By next-generation sequencing, using a panel of 523 genes, we performed analysis of copy number variations and of types and distribution of nonsynonymous mutations in 102 cases including 39 carmustine wafer (CW) treated cases. We also calculated tumor mutational burden (TMB). ML was applied using eXtreme Gradient Boosting for survival (XGBoost-Surv) to integrate clinical and radiological information with genomic data. Results: By ML modeling (concordance (c)- index = 0.682 for the best model), the role of predicting OS of radiological parameters including extent of resection, preoperative volume and residual volume was confirmed. An association between CW application and longer OS was also showed. Regarding gene mutations, a role in predicting OS was defined for mutations of BRAF and of other genes involved in the PI3K-AKT-mTOR signaling pathway. Moreover, an association between high TMB and shorter OS was suggested. Consistently, when a cutoff of 1.7 mutations/megabase was applied, cases with higher TMB showed significantly shorter OS than cases with lower TMB. Conclusions: The contribution of tumor volumetric data, somatic gene mutations and TBM in predicting OS of GG4 patients was defined by ML modeling
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