Experimental and theoretical analysis of Landauer erasure in nanomagnetic switches of different sizes

The authors acknowledge support by the European Union (FPVII (2007-2013) under G.A. n.318287 LANDAUER, and by MIUR-PRIN 2010–11 Project 2010ECA8P3 “DyNanoMag.”. M.P. and P.V. acknowledge funding from the Spanish Ministry of Economy and Competitiveness (Project No. MAT2012-36844); M.P. acknowledges support by Spanish Ministry of Economy and Competitiveness (grant BES-2013-063690).Bistable nanomagnetic switches are extensively used in storage media and magnetic memories, associating each logic state to a different equilibrium orientation of the magnetization. Here we consider the issue of the minimum energy required to change the information content of nanomagnetic switches, a crucial topic to face fundamental challenges of current technology, such as power dissipation and limits of scaling. The energy dissipated during a reset operation, also known as “Landauer erasure”, has been accurately measured at room temperature by vectorial magneto-optical measurements in arrays of elongated Permalloy nanodots. Both elliptical and rectangular dots were analysed, with lateral sizes ranging from several hundreds to a few tens of nanometers and thickness of either 10 nm or 5 nm. The experimental results show a nearly linear decrease of the dissipated energy with the dot volume, ranging from three to one orders of magnitude above the theoretical Landauer limit of kBT×ln(2). These experimental findings are corroborated by micromagnetic simulations showing that the significant deviations from the ideal macrospin behavior are caused by both inhomogeneous magnetization distribution and edge effects, leading to an average produced heat which is appreciably larger than that expected for ideal nanoswitches.PostprintPeer reviewe

Search for antihelium in cosmic rays

The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle Discovery during flight STS-91 in a 51.7 degree orbit at altitudes between 320 and 390 km. A total of 2.86 * 10^6 helium nuclei were observed in the rigidity range 1 to 140 GV. No antihelium nuclei were detected at any rigidity. An upper limit on the flux ratio of antihelium to helium of < 1.1 * 10^-6 is obtained.Comment: 18 pages, Latex, 9 .eps figure

Protons in near earth orbit

The proton spectrum in the kinetic energy range 0.1 to 200 GeV was measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS-91 at an altitude of 380 km. Above the geomagnetic cutoff the observed spectrum is parameterized by a power law. Below the geomagnetic cutoff a substantial second spectrum was observed concentrated at equatorial latitudes with a flux ~ 70 m^-2 sec^-1 sr^-1. Most of these second spectrum protons follow a complicated trajectory and originate from a restricted geographic region.Comment: 19 pages, Latex, 7 .eps figure

Evans Syndrome in Childhood: Long Term Follow-Up and the Evolution in Primary Immunodeficiency or Rheumatological Disease

Evans syndrome (ES) is a rare but challenging condition, characterized by recurrent and refractory cytopenia episodes. Recent discoveries highlighted that an appropriate diagnostic workup is fundamental to identify an underlying immune dysregulation such as primary immunodeficiencies or a rheumatological disease. We hereby describe clinical features and laboratory results of 12 pediatric patients affected by ES referred to the Pediatric Onco-Hematology Unit of Bologna. Patients experienced a median of four acute episodes of cytopenia with 9 years as median age at the onset of symptoms. In 8/12 (67%) patients an underlying etiology, primary immunodeficiencies, or rheumatological disease was identified. In 4/12 children, other immune manifestations were associated (Thyroiditis, Celiac disease, Psoriasis, Vitiligo, Myositis, Membranoproliferative Glomerulonephritis). ES remained the primary diagnosis in four patients (33%). At a median follow-up time of 4 years, 5/12 (42%) patients revealed a chronic ITP, partially responsive to second line therapy. Immunoglobulin Replacement Therapy (IRT) was effective with a good hematological values control in three patients with a secondary ES (ALPS, CVID, and a patient with Rubinstein Taybi Syndrome and a progressive severe B cell deficiency with hypogammaglobulinemia). Our experience highlights that, in pediatric patients, ES is often only the first manifestation of an immunological or rheumatological disease, especially when cytopenias are persistent or resistant to therapy, with an early-onset or when are associated with lymphadenopathy

Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

Screening for sickle cell disease: focus on newborn investigations

Drepanocytosis is a genetic disease relevant for its epidemiological, clinical and socio-economic aspects. In our country the prevalence is highly uneven with peaks in former malaria areas, but migration flows in recent years have led to significant changes. In this document we review the screening programs currently existing in Italy with particular emphasis on newborn screening, which in other countries around the world, including within Europe, is at most universal and mandatory. The essential laboratory issues are reviewed, from sampling aspects (cord blood or peripheral), to the analytical (analytical methods dedicated to neonatal screening and adult carrier detection) and post analytical (reporting, informative) ones. An economic analysis based on data collected in the province of Modena is also proposed, clearly showing that neonatal screening is also beneficial from an economic point of view

Screening for sickle cell disease: Focus on newborn investigations

Drepanocytosis is a genetic disease relevant for its epidemiological, clinical and socio-economic aspects. In our country the prevalence is highly uneven with peaks in former malaria areas, but migration flows in recent years have led to significant changes. In this document we review the screening programs currently existing in Italy with particular emphasis on newborn screening, which in other countries around the world, including within Europe, is at most universal and mandatory. The essential laboratory issues are reviewed, from sampling aspects (cord blood or peripheral), to the analytical (analytical methods dedicated to neonatal screening and adult carrier detection) and post analytical (reporting, informative) ones. An economic analysis based on data collected in the province of Modena is also proposed, clearly showing that neonatal screening is also beneficial from an economic point of view

Genome-wide analysis of differential transcriptional and epigenetic variability across human immune cell types

Abstract Background A healthy immune system requires immune cells that adapt rapidly to environmental challenges. This phenotypic plasticity can be mediated by transcriptional and epigenetic variability. Results We apply a novel analytical approach to measure and compare transcriptional and epigenetic variability genome-wide across CD14+CD16− monocytes, CD66b+CD16+ neutrophils, and CD4+CD45RA+ naïve T cells from the same 125 healthy individuals. We discover substantially increased variability in neutrophils compared to monocytes and T cells. In neutrophils, genes with hypervariable expression are found to be implicated in key immune pathways and are associated with cellular properties and environmental exposure. We also observe increased sex-specific gene expression differences in neutrophils. Neutrophil-specific DNA methylation hypervariable sites are enriched at dynamic chromatin regions and active enhancers. Conclusions Our data highlight the importance of transcriptional and epigenetic variability for the key role of neutrophils as the first responders to inflammatory stimuli. We provide a resource to enable further functional studies into the plasticity of immune cells, which can be accessed from: http://blueprint-dev.bioinfo.cnio.es/WP10/hypervariability

Enhanced Magneto-Optical Edge Excitation in Nanoscale Magnetic Disks

We report unexpected enhancements of the magneto-optical effect in ferromagnetic Permalloy disks of diameter D < 400 nm. The effect becomes increasingly pronounced for smaller D, reaching more than a 100% enhancement for D ¼ 100 nm samples. By means of experiments and simulations, the origin of this effect is identified as a nanoscale ring-shaped region at the disk edges, in which the magneto-optically induced electric polarization is enhanced. This leads to a modification of the electromagnetic near fields and causes the enhanced magneto-optical excitation, independent from any optical resonance.We acknowledge funding from the Basque Government (Program No. PI2012-47) and the Spanish Government (Project No.MAT2012-36844).Work at the Universidad de Cantabria has been supported by MICINN under Project No. FIS2013-45854-P