Quenched bond dilution in two-dimensional Potts models

We report a numerical study of the bond-diluted 2-dimensional Potts model using transfer matrix calculations. For different numbers of states per spin, we show that the critical exponents at the random fixed point are the same as in self-dual random-bond cases. In addition, we determine the multifractal spectrum associated with the scaling dimensions of the moments of the spin-spin correlation function in the cylinder geometry. We show that the behaviour is fully compatible with the one observed in the random bond case, confirming the general picture according to which a unique fixed point describes the critical properties of different classes of disorder: dilution, self-dual binary random-bond, self-dual continuous random bond.Comment: LaTeX file with IOP macros, 29 pages, 14 eps figure

BMJ Open

Introduction Guidelines for the treatment of steroid-dependent nephrotic syndrome (SDNS) and frequently relapsing nephrotic syndrome (FRNS) are lacking. Given the substantial impact of SDNS/FRNS on quality of life, strategies aiming to provide long-term remission while minimising treatment side effects are needed. Several studies confirm that rituximab is effective in preventing early relapses in SDNS/FRNS; however, the long-term relapse rate remains high (~70% at 2 years). This trial will assess the association of intravenous immunoglobulins (IVIgs) to rituximab in patients with SDNS/FRNS and inform clinicians on whether IVIg’s immunomodulatory properties can alter the course of the disease and reduce the use of immunosuppressive drugs and their side effects. Methods and analysis We conduct an open-label multicentre, randomised, parallel group in a 1:1 ratio, controlled, superiority trial to assess the safety and efficacy of a single infusion of rituximab followed by IVIg compared with rituximab alone in childhood-onset FRNS/SDNS. The primary outcome is the occurrence of first relapse within 24 months. Patients are allocated to receive either rituximab alone (375 mg/m²) or rituximab followed by IVIg, which includes an initial Ig dose of 2 g/kg, followed by 1.5 g/kg injections once a month for the following 5 months (maximum dose: 100 g). Ethics and dissemination The study has been approved by the ethics committee (Comité de Protection des Personnes) of Ouest I and authorised by the French drug regulatory agency (Agence Nationale de Sécurité du Médicament et des Produits de Santé). Results of the primary study and the secondary aims will be disseminated through peer-reviewed publications

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

AMORPHIZATION OF CRYSTALLINE COBALT AND TIN MULTILAYERS BY SOLID STATE REACTION AT ROOM TEMPERATURE

Des alliages amorphes Cox Sn1-x sont formés par diffusion à l'état solide, à température ambiante, dans des échantillons multicouches de cobalt et d'étain. Quelques propriétés des alliages ainsi formés sont comparées à celles des alliages amorphes de même composition obtenus par coévaporation à 77 K.Amorphous Cox Sn1-x alloys have been obtained, at room temperature, by interdiffusion from initially crystalline multilayers. The properties of these alloys (forming ability range, temperature variation of electrical resistance, crystallization temperature and magnetic behaviour) are compared to those of Cox, Sn1-x amorphous alloys formed by co-evaporation at 77 K

Ising spin glasses in the effective-interaction-approximation

Using an effective-interaction-approximation we study the critical lines of the Harris and (± 1)-Ising spin glasses. For the square lattice we recover the exact results of Harris Tc(η)/Tc(0) = 1 - 0.311 6 η2 and Domany Tc(p)/ Tc(1) = 1 - 3.209(1 - p). The critical concentration for ferromagnetism pc1 is in good agreement with known results and tends to its mean-field value pc1 = 1/2 when z, the coordination number, tends to infinity. Non-alternate lattices present a retrograde critical line, typical of annealed disorder, in the single-bond approximation. A cluster extension of the method on the triangular and honeycomb lattices indicates that this behaviour is unphysical for quenched disorder.Les lignes critiques des verres de spin de Harris et d'Ising (± 1) sont obtenues dans l'approximation de l'interaction effective. Pour le réseau carré nous retrouvons les résultats exacts de Harris Tc(η)/ Tc(0) = 1 - 0,3116 η2 et Domany Tc( p)/Tc(1) = 1 - 3,209(1 - p). La concentration critique pour le ferromagnétisme pc1 est en bon accord avec les résultats connus et tend vers sa valeur de champ moyen p c1 = 1/2 quand z, la coordinance du réseau, tend vers l'infini. Les réseaux non alternés ont une ligne critique rétrograde, typique pour le désordre recuit, dans l'approximation à une liaison. Un développement en amas pour les réseaux triangulaire et nid d'abeilles semble indiquer que ce comportement n'est pas physique dans le cas du désordre trempé

EXAFS STUDY OF AMORPHIZATION BY SOLID STATE REACTION IN Co/Sn MULTILAYERS

On a étudié l'amorphisation par réaction à l'état solide dans les multicouches de Co/Sn sur le poste EXAFS dispersif de LURE. On montre que cette technique permet de suivre dynamiquement le processus d'interdiffusion tant par les XANES que par l'EXAFS. On met en evidence deux processus simultanés : une réorganisation cristalline des métaux dans les couches, et une interdiffusion de Co et SnAmorphization by solid state reaction in Co/Sn multilayers has been studied by X-ray absorption spectroscopy in dispersive mode. The XANES and EXAFS parts of the spectra are used to follow dynamically the diffusion process. It is show that on annealing, in-layer crystalline reorganization and interdiffusion of Co and Sn occur simultaneously

Shortened first-line high-dose chemotherapy for patients with poor-prognosis aggressive lymphoma

Purpose: Randomized trial LNH93-3 was conducted on patients who had poor-prognosis aggressive lymphoma and were younger than 60 years with two to three factors of the age-adjusted International Prognostic Index to evaluate the benefit of early high-dose therapy (HDT) with autologous stem-cell transplantation (ASCT). Patients and Methods: Patients were randomized between doxorubicin, cyclophosphamide, vindesine, bleomycin, and prednisone (ACVBP) chemotherapy followed by sequential consolidation and an experimental shortened treatment consisting of three cycles with escalated doses of cyclophosphamide, epirubicin, vindesine, bleomycin, and prednisone and collection of peripheral-blood stem cells. On day 60, HDT was administered with 1,3-bis(2-chloroethyl)-1-nitrosourea, etoposide, cytarabine, and melphalan followed by ASCT. Results: Eligible patients (n = 370) with aggressive lymphoma were analyzed. For ACVBP (181 patients) and HDT (189 patients), respective complete remission rates were 64% and 63%. With a median follow-up of 60 months, 5-year overall survival and event-free survival for ACVBP and HDT were 60% +/- 8% and 46% +/- 8% (P = .007) and 52 +/- 8% and 39 8% (P = .01), respectively. Survival was independently affected by age greater than 40 years (P = .0003), T-cell phenotype (P = .009), bone marrow involvement (P = .003), and HDT treatment group (P = .04). Conclusion: Early HDT with ASCT in high-risk patients was inferior to the ACVBP chemotherapy regimen. These results indicate that the received dose-intensity before HDT was too low when compared with ACVBP and HDT and was given too early. (C) 2002 by American Society of Clinical Oncology

DIFFUSION MECHANISM IN Ce/Ni MULTILAYERS AS A FUNCTION OF THEIR PERIODS

We have studied the diffusion in Ce/Ni multilayers with different periods (65 Å, 195 Å, 325 Å). We have observed that the final state of the diffusion process could vary as a function of the period, giving respectively a homogeneous amorphous alloy, a homogeneous crystalline compound and mixed phases