Quantum-torque-induced breaking of magnetic domain walls in ultracold gases

A rich variety of physical effects in the spin dynamics arises at the interface (domain wall) between different magnetic materials. Engineered physical systems based on magnetic interlaced structures have received wide interest in the last years as a starting point to implement spin transistors, memories and other spintronic devices. In this work, we use a coherently-coupled mixture of ultracold bosonic gases to realize analogues of magnetic junctions. The spatial inhomogeneity of the atomic gas makes the system change its behavior from regions with oscillating magnetization, resembling a magnetic material in the presence of an external transverse field, to regions with a defined magnetization, as in magnetic materials with a ferromagnetic anisotropy stronger than external fields. Starting from a far-from-equilibrium fully polarized state, magnetic domain walls form spontaneously. We observe that the so-called quantum torque causes the breaking of such domain walls and the accumulated energy is released into short-wavelength magnetic waves that propagate in the system. Our results provide a novel platform for the study of far-from-equilibrium spin dynamics, free from dissipation and in regimes that are not easily accessible in solid-state systems.Comment: 6 pages, 4 figure

Long-Lasting Protective Effect of Posaconazole Prophylaxis in Patients with Acute Myeloid Leukemia Receiving Allogeneic Hematopoietic Stem Cell Transplantation

Abstract Patients with acute myeloid leukemia (AML) during induction chemotherapy and those who receive allogeneic hematopoietic stem cell transplantation (HSCT) are at higher risk of invasive fungal infections (IFI). In the present study, we investigated whether the risk of IFI in AML patients receiving HSCT might be affected by the antifungal prophylaxis with posaconazole administered during the induction/salvage chemotherapy treatment. Between August 2001 and April 2015, 130 patients with AML received itraconazole/fluconazole (group A) and 99 received posaconazole (group B) as antifungal prophylaxis after induction/salvage chemotherapy at 7 Italian centers and all patients received fluconazole as antifungal prophylaxis after HSCT. The median duration of antifungal prophylaxis after induction/salvage chemotherapy was significantly longer for patients in group A than for those in group B (24 days versus 20 days, P  = .019). The 1-year cumulative incidence of proven/probable IFI after HSCT was 14% and 4% in group A and group B, respectively ( P  = .012). Fungal-free survival and overall survival at 1 year after HSCT were 66% and 70% in group A, and 75% and 77% in group B ( P  = .139 and P  = .302), respectively. Multivariate logistic analysis identified the use of alternative donors (matched unrelated donor: odds ratio [OR], 3.25; haploidentical/partially matched related donor: OR, 3.19), antifungal prophylaxis with itraconazole/fluconazole (OR, 3.82), and reduced-intensity conditioning (OR, 4.92) as independent risk factors for the development of IFI after HSCT. In summary, the present study suggests that the protective effects of posaconazole during induction/salvage chemotherapy for AML patients may have long-lasting benefits and eventually contribute to reduce the risk of IFI when patients undergo allogeneic HSCT

Multicenter Experience Using Total Lymphoid Irradiation and Antithymocyte Globulin as Conditioning for Allografting in Hematological Malignancies

A non myeloablative conditioning with total lymphoid irradiation (TLI) and antithymocyte globulin (ATG) was shown to protect against graft-versus-host disease (GVHD). To evaluate the effects of TLI-ATG in a multicenter study, 45 heavily pretreated patients, median age 51, with lymphoid (n = 38) and myeloid (n = 7) malignancies were enrolled at 9 centers. Twenty-eight patients (62%) received at least 3 lines of treatment before allografting, and 13 (29%) had refractory/relapsed disease at the time of transplantation. Peripheral blood hematopoietic cells were from HLA identical sibling (n = 30), HLA-matched (n = 9), or 1 antigen HLA-mismatched (n = 6) unrelated donors. A cumulative TLI dose of 8 Gy was administered from day −11 through −1 with ATG at the dose of 1.5 mg/kg/day (from day −11 through −7). GVHD prophylaxis consisted of cyclosporine and mycophenolate mofetil. Donor engraftment was reached in 95% of patients. Grade II to IV acute GVHD (aGVHD) developed in 6 patients (13.3%), and in 2 of these patients, it developed beyond day 100. Incidence of chronic GVHD (cGVHD) was 35.8%. One-year nonrelapse mortality was 9.1%. After a median follow-up of 28 months (range, 3-57 months) from transplantation, median overall survival was not reached, whereas median event-free survival was 20 months. This multicenter experience confirms that TLI-ATG protects against GVHD and maintains graft-vs-tumor effects

Metalation of olefinic positions in norbornadiene: enhancement and attenuation of kinetic CH-acidities by a neighboring enesilane moiety

When treated with BuLi in the presence of Na or K tert-butoxide, 2-(trimethylsilyl)- and 2-(triethylsilyl)norbornadiene undergo H/metal-exchange mainly at the 5-position. The latter position is slightly activated relative to unsubstituted norbornadiene while the 2 other olefinic positions prove to be a quite inert. Two side reactions are obsd.: the metalation of Si-attached Me groups and the replacement of the entire trialkylsilyl group by a metal atom. [on SciFinder (R)

Microwave-Assisted Isomerizations of Epoxides to Allylic Alcohols

The present work reports a study on the isomerization reactions of several alkyl epoxides to the corresponding allylic alcohols or bicyclic alcohols under microwave irradiation. The reaction occurred in the presence of lithium diisopropylamide as a base and different experimental conditions in terms of solvent, amount of the base, times and temperatures. The traditional heating with an oil-bath and the use of alternative organometallic bases, as the Lochmann-Schlosser bases, have been furthermore compared with the microwave heating. The results obtained show that the use of microwave irradiations on promoting the isomerization of epoxides gives access to a series of synthetically useful products, among which allylic alcohols and bicyclic alcohols, depending on the starting substrate

Composés organométalliques en synthèse regio- et énantiosélective (structure et réactivité)

Ce travail présente deux études en chimie organométallique (organolithiens). Dans le premier chapitre, des réactions d'isomérisation réalisées en présence de superbases bimétalliques sont impliquées, et la transformation d'aziridines fonctionnalisées est examinée. Deux voies sont possibles : la b-élimination ou la cyclisation 4-exo intracyclique. Le processus réactionnel étant accompagné de la formation de centre(s) stéréogène(s), une approche asymétrique est explorée avec 3-APLi's. Le deuxième chapitre s'intéresse à l'étude structurale de phosphines (boranes) lithiées dans le but d'aborder la synthèse énantiosélective d'alkylphosphines P-stéréogéniques. Ce travail de thèse a permis d'examiner la structure en solution d'une phosphine borane lithiée modèle (Ph2P(BH3)Li) en solution par spectroscopie RMN multinoyaux (1H, 6Li, 13C, 11B, 31P). L'affinité du phosphure avec le BuLi puis la LDA a ensuite été examinée.Questo lavoro di tesi è stato focalizzato su due tematiche alla chimica degli organometalli (ed in particolare degli organolitio derivati). Nella prima parte sono state studiate le reazioni di isomerizzazione in presenza di superbasi bimetalliche ed è stata esaminata la reattività di aziridine funzionlizzate. Due meccanismi sono possibili : la b-eliminazione e la ciclizzazione 4-exo intramolecolare. Dato che la reazione è accompagnata dalla formazione di uno o più centri stereogenici, è stata anche studiata una versione asimmetrica. La seconda parte descrive uno studio di fosfine-borani litiati. Questo lavoro è parte di un programma consistente nella sintesi di alchifosfine P-stereogeniche enantioarricchite. Il nostro contributo consiste nella determinazione della struttura di una litio fosfide-borano (Ph2P(BH3)Li) grazie alla tecnica di analisi NMR multinucleare (1H, 6Li, 13C, 11B, 31P). È stata anche analizzata l'affinità della lithio fosfide per il BuLi e poi per l'LDA.ROUEN-BU Sciences (764512102) / SudocROUEN-BU Sciences Madrillet (765752101) / SudocSudocFranceF

Synthesis of non-racemic β-branched α-(aminoalkyl)-acrylates from naturally occurring amino acids

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