Quadratic integrals of motions for the systems of identical particles-quantum case

The quantum dynamical systems of identical particles admitting an additional integral quadratic in momenta are considered. It is found that an appropriate ordering procedure exists which allows to convert the classical integrals into their quantum counterparts. The relation to the separation of variables in Schroedinger equation is discussed.Comment: 6 pages, no figure

Steering effects on growth instability during step-flow growth of Cu on Cu(1,1,17)

Kinetic Monte Carlo simulation in conjunction with molecular dynamics simulation is utilized to study the effect of the steered deposition on the growth of Cu on Cu(1,1,17). It is found that the deposition flux becomes inhomogeneous in step train direction and the inhomogeneity depends on the deposition angle, when the deposition is made along that direction. Steering effect is found to always increase the growth instability, with respect to the case of homogeneous deposition. Further, the growth instability depends on the deposition angle and direction, showing minimum at a certain deposition angle off-normal to (001) terrace, and shows a strong correlation with the inhomogeneous deposition flux. The increase of the growth instability is ascribed to the strengthened step Erlich Schwoebel barrier effects that is caused by the enhanced deposition flux near descending step edge due to the steering effect.Comment: 5 page

Alterations in the self-renewal and differentiation ability of bone marrow mesenchymal stem cells in a mouse model of rheumatoid arthritis

Introduction: Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease primarily involving the synovium. Evidence in recent years has suggested that the bone marrow (BM) may be involved, and may even be the initiating site of the disease. Abnormalities in haemopoietic stem cells' (HSC) survival, proliferation and aging have been described in patients affected by RA and ascribed to abnormal support by the BM microenvironment. Mesenchymal stem cells (MSC) and their progeny constitute important components of the BM niche. In this study we test the hypothesis that the onset of inflammatory arthritis is associated with altered self-renewal and differentiation of bone marrow MSC, which alters the composition of the BM microenvironment. Methods: We have used Balb/C Interleukin-1 receptor antagonist knock-out mice, which spontaneously develop RA-like disease in 100% of mice by 20 weeks of age to determine the number of mesenchymal progenitors and their differentiated progeny before, at the start and with progression of the disease. Results: We showed a decrease in the number of mesenchymal progenitors with adipogenic potential and decreased bone marrow adipogenesis before disease onset. This is associated with a decrease in osteoclastogenesis. Moreover, at the onset of disease a significant increase in all mesenchymal progenitors is observed together with a block in their differentiation to osteoblasts. This is associated with accelerated bone loss. Conclusions: Significant changes occur in the BM niche with the establishment and progression of RA-like disease. Those changes may be responsible for aspects of the disease, including the advance of osteoporosis. An understanding of the molecular mechanisms leading to those changes may lead to new strategies for therapeutic intervention

Un nou mètode d'enregistrament de dades magnètiques pot reduir la grandària de les memòries

La tecnologia dels ordinadors a dia d'avui es basa en l'habilitat d'escriure, llegir, i emmagatzemar informació digital de la manera més eficaç possible i en el mínim espai. La miniaturització, però, comporta molts problemes que físics i enginyers de tot el món s'esforcen en solucionar. Un equip d'investigadors de l'Institut Català de Nanotecnologia, ICREA, i de la UAB, en col·laboració amb l'institut SPINTEC de Grenoble a França, ha descobert un nou mètode d'enregistrament de dades magnètiques que permet que el procés d'escriptura dels bits sigui ràpid, consumeixi poca energia, i minimitzi l'error, alhora que pot reduir la grandària de les memòries.La tecnología de los ordenadores a día de hoy se basa en la habilidad de escribir, leer, y almacenar información digital de la manera más eficaz posible y en el mínimo espacio. La miniaturización, sin embargo, conlleva muchos problemas que físicos e ingenieros de todo el mundo se esfuerzan por solucionar. Un equipo de investigadores del Instituto Catalán de Nanotecnología, ICREA, y de la UAB, en colaboración con el instituto SPINTEC de Grenoble en Francia, ha descubierto un nuevo método de grabación de datos magnéticos que permite que el proceso de escritura de los bits sea rápido, consuma poca energía, y minimice el error, a la vez que puede reducir el tamaño de las memorias

Retained Laser Fibre Following Endovenous Laser Ablation

IntroductionTo report the breakage and retention of a laser fibre, following endovenous laser ablation (EVLA).Case reportThe great saphenous vein (GSV) of a 57 year-old man was treated with EVLA. During withdrawal, a flash of light was seen from a hole that had burned through the introducer sheath. This device was removed and a second sheath and laser fibre inserted to complete the ablation procedure. A follow-up duplex scan identified a residual length of laser fibre within the GSV that was removed by an additional surgical procedure. A change in laser fibre length had not been identified during the initial procedure.DiscussionThis case highlights the importance of routinely inspecting the sheath and fibre following EVLA to ensure that they have been removed intact

A comparison of existing risk prediction models in patients undergoing venoarterial extracorporeal membrane oxygenation

© 2020 The Author(s) Background: Patients undergoing consideration for venoarterial extracorporeal membrane oxygenation (VA-ECMO) require an immediate risk profile assessment in the setting of incomplete information. A number of survival prediction models for critically ill patients and patients undergoing elective cardiac surgery or institution of VA-ECMO support have been designed. We assess the ability of these models to predict outcomes in a cohort of patients undergoing institution of VA-ECMO for cardiogenic shock or cardiac arrest. Methods: Fifty-one patients undergoing institution of VA-ECMO support were retrospectively analyzed. APACHE II, SOFA, SAPS II, Encourage, SAVE, and ACEF scores were calculated. Their ability to predict outcomes were assessed. Results: Indications for ECMO support included postcardiotomy shock (25%), ischemic etiologies (39%), and other etiologies (36%). Pre-ECMO arrest occurred in 73% and 41% of patients underwent cannulation during arrest. Survival to discharge was 39%. Three survival prediction model scores were significantly higher in nonsurvivors to discharge than surivors; the Encourage score (25.4 vs 20; p =.04), the APACHE II score (23.6 vs 19.2; p =.05), and the ACEF score (3.1 vs 1.8; p =.03). In ROC analysis, the ACEF score demonstrated the greatest predictive ability with an AUC of 0.7. Conclusions: A variety of survival prediction model scores designed for critically ill ICU and VA-ECMO patients demonstrated modest discriminatory ability in the current cohort of patients. The ACEF score, while not designed to predict survival in critically ill patients, demonstrated the best discriminatory ability. Furthermore, it is the simplest to calculate, an advantage in the emergent setting

Spin and Charge Correlations in Quantum Dots: An Exact Solution

The inclusion of charging and spin-exchange interactions within the Universal Hamiltonian description of quantum dots is challenging as it leads to a non-Abelian action. Here we present an {\it exact} analytical solution of the probem, in particular, in the vicinity of the Stoner instabilty point. We calculate several observables, including the tunneling density of states (TDOS) and the spin susceptibility. Near the instability point the TDOS exhibits a non-monotonous behavior as function of the tunneling energy, even at temperatures higher than the exchange energy. Our approach is generalizable to a broad set of observables, including the a.c. susceptibility and the absorption spectrum for anisotropic spin interaction. Our results could be tested in nearly ferromagnetic materials.Comment: JETPL class, 6 pages, 2 figure