Spatial multiplexing in near field MIMO channels with reconfigurable intelligent surfaces

We consider a multiple-input multiple-output (MIMO) channel in the presence of a reconfigurable intelligent surface (RIS). Specifically, our focus is on analysing the spatial multiplexing gains in line-of-sight and low-scattering MIMO channels in the near field. We prove that the channel capacity is achieved by diagonalising the end-to-end transmitter-RIS-receiver channel, and applying the water-filling power allocation to the ordered product of the singular values of the transmitter-RIS and RIS-receiver channels. The obtained capacity-achieving solution requires an RIS with a non-diagonal matrix of reflection coefficients. Under the assumption of nearly-passive RIS, that is, no power amplification is needed at the RIS, the water-filling power allocation is necessary only at the transmitter. We refer to this design of RIS as a linear, nearly-passive, reconfigurable electromagnetic object (EMO). In addition, we introduce a closed-form and low-complexity design for RIS, whose matrix of reflection coefficients is diagonal with unit-modulus entries. The reflection coefficients are given by the product of two focusing functions: one steering the RIS-aided signal towards the mid-point of the MIMO transmitter and one steering the RIS-aided signal towards the mid-point of the MIMO receiver. We prove that this solution is exact in line-of-sight channels under the paraxial setup. With the aid of extensive numerical simulations in line-of-sight (free-space) channels, we show that the proposed approach offers performance (rate and degrees of freedom) close to that obtained by numerically solving non-convex optimization problems at a high computational complexity. Also, we show that it provides performance close to that achieved by the EMO (non-diagonal RIS) in most of the considered case studies

Fotemustine plus etoposide, cytarabine and melphalan (FEAM) as a new conditioning regimen for lymphoma patients undergoing auto-SCT: A multicenter feasibility study

BEAM is a widely used conditioning regimen for relapsed/refractory lymphoma patients undergoing auto-SCT. We conducted a multicenter study with an alternative regimen (fotemustine plus etoposide, cytarabine and melphalan (FEAM)) in which BCNU was substituted by the chloroethylnitrosourea fotemustine (FTM). Eighty-four patients with relapsed/refractory Hodgkin's (n20) and non-Hodgkin's lymphoma (n64) were conditioned with a FEAM regimen (FTM 150 mg/m 2 on days -7, -6, etoposide 200 mg/m 2 and cytarabine 400 mg/m 2 on days -5, -4, -3, -2 and melphalan 140 mg/m 2 on day -1). Patients were evaluated for toxicity and engraftment parameters. Median times to neutrophil (500 × 10 9 /l) and plt (20 000 × 10 9 /l) engraftment were 11 and 13 days, respectively. Grade 3 mucositis occurred in 19 patients (23%), while G3 nausea/vomiting and G3 diarrhea were observed in 13 (15%) and 6 (7%) patients, respectively. No severe hepatic, renal or pulmonary toxicity was detected. Seven patients (7%) experienced G4 mucositis, while no other G4 toxicities or unexpected adverse events of any grade were recorded. Transplant-related mortality was 2.4%. We conclude that a FEAM regimen is feasible and safe. Although toxicity and engraftment times compared favorably with BEAM, longer follow-up is needed to evaluate fully its efficacy and long-term safety. © 2010 Macmillan Publishers Limited All rights reserved

Transition metal b-site substitutions in laalo3 perovskites reorient bio-ethanol conversion reactions

LaAlO3 perovskites, as such and with 25% molar Al substitution by Cu, Co, or Ga, have been prepared by sol-gel methods and tested as heterogeneous catalysts in the gas-phase conversion of ethanol. LaAlO3 presented a significant acidic character, with high formation of ethylene by ethanol dehydration. B-site substitutions increased the basicity of the catalysts, favoring the dehydrogenation of ethanol to acetaldehyde. The most reducible Cu-and Co-substituted materials, characterized by easier formation of surface oxygen vacancies, promoted the self-condensation of acetaldehyde by the Tishchenko mechanism, with formation of acetone and odd-carbon number products. Aldol coupling of acetaldehyde, favored on pure and Ga-substituted LaAlO3, led to the formation of butadiene and hexadiene. The role of Ga insertion, favoring both dehydrogenation of ethylene and dehydration of higher alcohols, corresponds to an amphoteric character. The formation of olefins and diolefins on all catalysts suggests that LaAl-based materials present the most acidic character among La-perovskites

Magnetic separation and high reusability of chloroperoxidase entrapped in multi polysaccharide micro-supports

Enzyme immobilization on magnetic supports represents a great advantage for the industrial application of enzymatic catalysis since it allows an easy recovery of the catalyst, avoiding any contamination of the product by residual enzyme. Iron oxide nanoparticles are very useful for this purpose. Using a polymer to diminish the interaction between the magnetic cores themselves, can improve the colloidal stability of the support and prevent any interaction with the environment that would affect both support properties and enzyme stability. For this reason, in this work different magnetic micro-supports, based on polydopamine-coated iron oxide nanoparticles with a multi polysaccharide shell, have been developed. These supports have been used to immobilize chloroperoxidase, a very interesting enzyme, able to catalyze many reactions of large-scale interest, but whose application is limited by its sensitivity to reaction conditions. The multi polysaccharide shells of the supports were obtained through a combination of chitosan and alginate. An in-depth analysis of physicochemical and catalytic properties of all the developed magnetic supports is reported. CPO was successfully immobilized with an efficiency of entrapment between 92% and 100% in the case of supports with chitosan in the interior or outer shell respectively. A very good chemical stability of the support under reaction conditions was observed in the case of an interior shell of alginate and an outer coating of chitosan, together with an excellent reusability of the immobilized enzyme, that was recycled to catalyze up to 25 consecutive reaction cycles

Large-order NSPT for lattice gauge theories with fermions:the plaquette in massless QCD

Numerical Stochastic Perturbation Theory (NSPT) allows for perturbative computations in quantum field theory. We present an implementation of NSPT that yields results for high orders in the perturbative expansion of lattice gauge theories coupled to fermions. The zero-momentum mode is removed by imposing twisted boundary conditions; in turn, twisted boundary conditions require us to introduce a smell degree of freedom in order to include fermions in the fundamental representation. As a first application, we compute the critical mass of two flavours of Wilson fermions up to order $O(\beta^{-7})$ in a ${\mathrm{SU}}(3)$ gauge theory. We also implement, for the first time, staggered fermions in NSPT. The residual chiral symmetry of staggered fermions protects the theory from an additive mass renormalisation. We compute the perturbative expansion of the plaquette with two flavours of massless staggered fermions up to order $O(\beta^{-35})$ in a ${\mathrm{SU}}(3)$ gauge theory, and investigate the renormalon behaviour of such series. We are able to subtract the power divergence in the Operator Product Expansion (OPE) for the plaquette and estimate the gluon condensate in massless QCD. Our results confirm that NSPT provides a viable way to probe systematically the asymptotic behaviour of perturbative series in QCD and, eventually, gauge theories with fermions in higher representations.Comment: 49 pages, 28 figures. Revised version, to be published in EPJC. Some references added, typos corrected, and improved discussion on finite-volume effect

Perturbative expansions from Monte Carlo simulations at weak coupling: Wilson loops and the static-quark self-energy

Perturbative coefficients for Wilson loops and the static-quark self-energy are extracted from Monte Carlo simulations at weak coupling. The lattice volumes and couplings are chosen to ensure that the lattice momenta are all perturbative. Twisted boundary conditions are used to eliminate the effects of lattice zero modes and to suppress nonperturbative finite-volume effects due to Z(3) phases. Simulations of the Wilson gluon action are done with both periodic and twisted boundary conditions, and over a wide range of lattice volumes (from $3^4$ to $16^4$) and couplings (from $\beta \approx 9$ to $\beta \approx 60$). A high precision comparison is made between the simulation data and results from finite-volume lattice perturbation theory. The Monte Carlo results are shown to be in excellent agreement with perturbation theory through second order. New results for third-order coefficients for a number of Wilson loops and the static-quark self-energy are reported.Comment: 36 pages, 15 figures, REVTEX documen

apeNEXT: A multi-TFlops Computer for Simulations in Lattice Gauge Theory

We present the APE (Array Processor Experiment) project for the development of dedicated parallel computers for numerical simulations in lattice gauge theories. While APEmille is a production machine in today's physics simulations at various sites in Europe, a new machine, apeNEXT, is currently being developed to provide multi-Tflops computing performance. Like previous APE machines, the new supercomputer is largely custom designed and specifically optimized for simulations of Lattice QCD.Comment: Poster at the XXIII Physics in Collisions Conference (PIC03), Zeuthen, Germany, June 2003, 3 pages, Latex. PSN FRAP15. Replaced for adding forgotten autho

Body composition changes and cardiometabolic benefits of a balanced Italian Mediterranean Diet in obese patients with metabolic syndrome

Metabolic syndrome (MS) is a cluster of metabolic alteration associated with a higher risk of cardiovascular disease and overall mortality than the single alterations alone. The Italian Mediterranean Diet (IMD) can exert a positive effect on cardiovascular risk and related morbidity and mortality. The aim was to evaluate the benefits of dietary intervention based on a typical IMD on body composition, cardiometabolic changes and reduction in cardiovascular disease in patients with MS. Eighty White Italian subjects with MS were prescribed a balanced hypocaloric IMD. We investigated dietary habits and impact of the diet on health status, blood biochemical markers, anthropometric measurements and body composition during a 6-month follow-up period. Body composition, fat mass and distribution were assessed by Dual X-ray absorptiometry. Adherence to the IMD led to a decrease in body weight (102.59 ± 16.82 to 92.39 ± 15.94 kg, p < 0.001), body mass index (BMI) (38.57 ± 6.94 to 35.10 ± 6.76, <0.001) and waist circumference (112.23 ± 12.55 vs 92.42 ± 18.17 cm, p < 0.001). A significant loss of total body fat especially in waist region was observed. The MS was resolved in 52 % of the patients. Significant improvements in systolic and diastolic blood pressure and fasting glucose occurred. Low-density lipoprotein cholesterol was reduced from 128.74 ± 33.18 to 108.76 ± 38.61 mg/dl (p < 0.001), triglycerides from 169.81 ± 80.80 to 131.02 ± 63.88 mg/dl (p < 0.001). The present results suggest that a dietary intervention based on a typical IMD effectively promotes weight loss and reduces the growing burden of cardiovascular risk factors that typifies patients with MS