157 research outputs found
Quasi-particle spectrum and entanglement generation after a quench in the quantum Potts spin chain
Recently, a non-trivial relation between the quasi-particle spectrum and
entanglement entropy production was discovered in non-integrable quenches in
the paramagnetic Ising quantum spin chain. Here we study the dynamics of
analogous quenches in the quantum Potts spin chain. Tuning the parameters of
the system, we observe a sudden increase in the entanglement production rate,
which is shown to be related to the appearance of new quasiparticle excitations
in the post-quench spectrum. Our results demonstrate the generality of the
effect and support its interpretation as the non-equilibrium version of the
well-known Gibbs paradox related to mixing entropy which appears in systems
with a non-trivial quasi-particle spectrum.Comment: 15 pages, pdflatex, 30 pdf figures. v2: reformatted, 22 pages, typos
correcte
Bloch oscillations and the lack of the decay of the false vacuum in a one-dimensional quantum spin chain
We consider the decay of the false vacuum, realised within a quantum quench
into an anti-confining regime of the Ising spin chain with a magnetic field
opposite to the initial magnetisation. Although the effective linear potential
between the domain walls is repulsive, the time evolution of correlations still
shows a suppression of the light cone and a reduction of vacuum decay. The
suppressed decay is a lattice effect, and can be assigned to emergent Bloch
oscillations.Comment: 12 pages, 6 figures, pdflatex file. v2: 14 pages, new material and
references added, improved discussion, main results and conclusions unchange
Rituximab for eosinophilic granulomatosis with polyangiitis: a systematic review of observational studies
Objective
To analyse the available evidence about the use of rituximab (RTX) and other biologic agents in eosinophilic granulomatosis with polyangiitis (EGPA) patients and to provide useful findings to inform the design of future, reliable clinical trials.
Methods
A systematic review was performed. A systematic search was conducted in PubMed/MEDLINE, Scopus, Web of Science and the Cochrane library databases on RTX, and an extensive literature search was conducted on other biologic agents.
Results
Forty-five papers pertinent to our questions were found: 16 retrospective cohort studies, 8 case series, 3 prospective cohort studies and 18 single case reports, for a total of 368 EGPA patients. More than 80% of evaluable patients achieved complete or partial remission with a tendency towards a higher rate of complete response in the pANCA-positive subgroup.
Conclusion
Although the majority of the evaluable EGPA patients treated with RTX appears to achieve complete remission, we strongly believe that a number of sources of heterogeneity impair a clear interpretation of results and limit their transferability in clinical practice. Differences in design, enrolment criteria, outcome definition and measurement make a comparison among data obtained from studies on RTX and other biologic agents unreliable
Positive Least Energy Solutions and Phase Separation for Coupled Schrodinger Equations with Critical Exponent: Higher Dimensional Case
We study the following nonlinear Schr\"{o}dinger system which is related to
Bose-Einstein condensate: {displaymath} {cases}-\Delta u +\la_1 u = \mu_1
u^{2^\ast-1}+\beta u^{\frac{2^\ast}{2}-1}v^{\frac{2^\ast}{2}}, \quad x\in
\Omega, -\Delta v +\la_2 v =\mu_2 v^{2^\ast-1}+\beta v^{\frac{2^\ast}{2}-1}
u^{\frac{2^\ast}{2}}, \quad x\in \om, u\ge 0, v\ge 0 \,\,\hbox{in \om},\quad
u=v=0 \,\,\hbox{on \partial\om}.{cases}{displaymath} Here \om\subset \R^N
is a smooth bounded domain, is the Sobolev critical
exponent, -\la_1(\om)0 and , where
\lambda_1(\om) is the first eigenvalue of with the Dirichlet
boundary condition. When \bb=0, this is just the well-known Brezis-Nirenberg
problem. The special case N=4 was studied by the authors in (Arch. Ration.
Mech. Anal. 205: 515-551, 2012). In this paper we consider {\it the higher
dimensional case }. It is interesting that we can prove the existence
of a positive least energy solution (u_\bb, v_\bb) {\it for any } (which can not hold in the special case N=4). We also study the limit
behavior of (u_\bb, v_\bb) as and phase separation is
expected. In particular, u_\bb-v_\bb will converge to {\it sign-changing
solutions} of the Brezis-Nirenberg problem, provided . In case
\la_1=\la_2, the classification of the least energy solutions is also
studied. It turns out that some quite different phenomena appear comparing to
the special case N=4.Comment: 48 pages. This is a revised version of arXiv:1209.2522v1 [math.AP
Low-dose oral imatinib in the treatment of systemic sclerosis interstitial lung disease unresponsive to cyclophosphamide: a phase II pilot study.
NTRODUCTION:
Pulmonary involvement represents a major cause of death of systemic sclerosis (SSc) patients. Recent data suggest that tyrosine kinase inhibitors, such as imatinib, may be a therapeutic option for SSc patients. However, preliminary published clinical trials were inconclusive about imatinib efficacy and showed side effects. The purpose of this study was to verify efficacy and tolerability of low-dose imatinib on interstitial lung disease in a cohort of SSc patients unresponsive to cyclophosphamide therapy.
METHODS:
Thirty consecutive SSc patients with active pulmonary involvement, unresponsive to cyclophosphamide, were treated with imatinib 200 mg/day for 6 months followed by a 6-month follow-up. A "good response" was defined as an increase of forced vital capacity (FVC) by more of 15% and/or increase of diffusing capacity of carbon monoxide (DLCO) >15% and PaO2 > 90% of initial value and high-resolution computed tomography (HRCT)-scan pattern unchanged or improved.
RESULTS:
Twenty-six patients completed the study. Three patients died and one patient was lost to follow-up. Four patients (15.32%) had a good response, 7 worsened and 15 had a stabilized lung disease. Overall, 19 (73.07%) patients had an improved or stabilized lung disease. After a 6-month follow-up, 12 (54.5%) of the 22 patients showed an improved or stabilized lung disease.
CONCLUSIONS:
Lung function was stabilized in a large proportion of patients unresponsive to cyclophosphamide therapy and a beneficial outcome emerged from the analysis of HRCT lung scans. There was no significant improvement of skin involvement, and the low dose was well tolerated. These data provide useful suggestions to design future randomized clinical trials for SSc therapeutics
Low-dose oral imatinib in the treatment of systemic sclerosis interstitial lung disease unresponsive to cyclophosphamide: a phase II pilot study
Introduction: Pulmonary involvement represents a major cause of death of systemic sclerosis (SSc) patients. Recent data suggest that tyrosine kinase inhibitors, such as imatinib, may be a therapeutic option for SSc patients. However, preliminary published clinical trials were inconclusive about imatinib efficacy and showed side effects. The purpose of this study was to verify efficacy and tolerability of low-dose imatinib on interstitial lung disease in a cohort of SSc patients unresponsive to cyclophosphamide therapy.Methods: Thirty consecutive SSc patients with active pulmonary involvement, unresponsive to cyclophosphamide, were treated with imatinib 200 mg/day for 6 months followed by a 6-month follow-up. A "good response" was defined as an increase of forced vital capacity (FVC) by more of 15% and/or increase of diffusing capacity of carbon monoxide (DLCO) > 15% and PaO2 > 90% of initial value and high-resolution computed tomography (HRCT)-scan pattern unchanged or improved.Results: Twenty-six patients completed the study. Three patients died and one patient was lost to follow-up. Four patients (15.32%) had a good response, 7 worsened and 15 had a stabilized lung disease. Overall, 19 (73.07%) patients had an improved or stabilized lung disease. After a 6-month follow-up, 12 (54.5%) of the 22 patients showed an improved or stabilized lung disease.Conclusions: Lung function was stabilized in a large proportion of patients unresponsive to cyclophosphamide therapy and a beneficial outcome emerged from the analysis of HRCT lung scans. There was no significant improvement of skin involvement, and the low dose was well tolerated. These data provide useful suggestions to design future randomized clinical trials for SSc therapeutics
S.13.1 Safety and efficacy of rituximab in SSc: an analysis from the European Scleroderma Trial and Research Group
Objectives. Objective of this multicentre, observational study was to assess effects and safety of rituximab (RTX) using the European Scleroderma Trial and Research Group (EUSTAR) cohort. Methods. EUSTAR centres were asked to provide specific data about SSc patients treated with RTX. Primary endpoints were predefined for different disease manifestations and compared between baseline and follow-up. Normally distributed data, analysed by paired t-test, are shown as mean (s.d.), and non-parametric data, analysed by Wilcoxon matched paired signed-rank test, are shown as median and interquartile range. Results. Data on 72 SSc patients treated with RTX were captured from 27 EUSTAR centres (51 females/21 males, 52 diffuse/19 limited, age 51 (44-60) years, disease duration 6 (3-10) years, 47 anti-Scl-70 positive). The most frequent RTX application scheme was 1000 mg × 2 within 2 weeks (57/72 patients). Co-treatment with other immunosuppressive drugs was reported in 28 patients. The modified Rodnan skin score (mRSS) significantly decreased vs baseline at 7 (5-9) months follow-up (n = 47, 18.2 + 10.9 vs 14.5 + 9.9, P = 0.0002). This was true for both patients with later disease stages and also for patients with earlier, extended skin fibrosis (dSSc with mRSS >16 at baseline, n = 26; 26.5 + 6.8 vs 20.4 + 8.9, P < 0.0001, reduction by 29.9%). S-HAQ was unchanged, but the European SSc activity score improved after rituximab treatment [n = 10; 3.7 (2.6-6.4) vs 1.7 (0.9-2.5), P = 0.01]. RTX had no effects on lung fibrosis (FVC, DLCO, TLC, HRCT score) in n = 11 patients with evidence for SSc-ILD. In SSc-polyarthritis patients, the DAS-28 declined at 6 months follow-up without reaching statistical significance [n = 8; 4.8 (2.5-7.5) vs 3.7 (2.6-6.6); p = 0.3]. Of 8, 5patients were RF and/or anti-CCP antibody positive. Similar results were obtained for secondary outcome measures (tender and swollen joint count, VAS, CRP, ESR). Additional positive effects of RTX were seen on SSc-related myopathy (CK levels, 273 + 177 vs 184 + 139; n = 12, P = 0.03) and on digital ulcers [total number per patient 1 (1-3) vs 0 (0-1); n = 23; P = 0.0086]. During RTX treatment 14 patients had infections, 3 serum sickness, 2 allergic reactions and 1 lung fibrosis aggravation, 29 fatigue and 9 nausea. Four patients died, one possibly related to RTX treatment (pneumonia and cardiac failure 1.5 months after RTX infusion). Conclusion. This large EUSTAR cohort study points at positive effects of RTX in particular on skin fibrosis, and suggests randomized controlled trial in SSc patient
Activity of the antiarrhythmic drug amiodarone against Leishmania (L.) infantum: an in vitro and in vivo approach
<div><p>Abstract Background: Considering the high toxicity and limited therapies available for treating visceral leishmaniasis (VL), the drug repositioning approach represents a faster way to deliver new therapies to the market. Methods: In this study, we described for the first time the activity of a potent antiarrhythmic, amiodarone (AMD), against L. (L.)infantum and its in vitro and in vivo activity. Results: The evaluation against promastigotes has shown that amiodarone presents leishmanicidal effect against the extracellular form, with an IC50 value of 10 μM. The activity was even greater against amastigotes in comparison with promastigotes with an IC50 value of 0.5 μM. The selectivity index in relation to the intracellular form demonstrated that the antiparasitic activity was approximately 56 times higher than its toxicity to mammalian cells. Investigation of the in vivo AMD activity in the L. infantum-infected hamster model showed that 51 days after the initial infection, amiodarone was unable to reduce the parasite burden in the spleen and liver when treated for 10 consecutive days, intraperitoneally, at 50 mg/kg/day, as determined by qPCR. Although not statistically significant, AMD was able to reduce the parasite burden by 20% in the liver when treated for 10 consecutive days, orally, at 100 mg/kg/day; no reduction in the spleen was found by qPCR. Conclusions: Our findings may help further drug design studies seeking new AMD derivatives that may provide new candidates with an in vitro selectivity close to or even greater than that observed in the prototype delivering effectiveness in the experimental model of VL.</p></div
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