We report a large enhancement of thermally injected spin current in normal metal (NM)/antiferromagnet (AF)/yttrium iron garnet (YIG), where a thin AF insulating layer of NiO or CoO can enhance the ...spin current from YIG to a NM by up to a factor of 10. The spin current enhancement in NM/AF/YIG, with a pronounced maximum near the Néel temperature of the thin AF layer, has been found to scale linearly with the spin-mixing conductance at the NM/YIG interface for NM=3d, 4d, and 5d metals. Calculations of spin current enhancement and spin mixing conductance are qualitatively consistent with the experimental results.
The advent of spin transfer torque effect accommodates site-specific switching of magnetic nanostructures by current alone without magnetic field. However, the critical current density required for ...usual spin torque switching remains stubbornly high around 10(6)-10(7) A cm(-2). It would be fundamentally transformative if an electric field through a voltage could assist or accomplish the switching of ferromagnets. Here we report electric-field-assisted reversible switching in CoFeB/MgO/CoFeB magnetic tunnel junctions with interfacial perpendicular magnetic anisotropy, where the coercivity, the magnetic configuration and the tunnelling magnetoresistance can be manipulated by voltage pulses associated with much smaller current densities. These results represent a crucial step towards ultralow energy switching in magnetic tunnel junctions, and open a new avenue for exploring other voltage-controlled spintronic devices.
Much theoretical and experimental attention has been focused on the electrical switching of the antiferromagnetic (AFM) Néel vector via spin-orbit torque. Measurements employing multiterminal ...patterned structures of Pt/AFM show recurring signals of the supposedly planar Hall effect and magnetoresistance, implying AFM switching. We show in this Letter that similar signals have been observed in structures with and without the AFM layer, and of an even larger magnitude using different metals and substrates. These may not be the conclusive evidence of spin-orbit torque switching of AFM, but the thermal artifacts of patterned metal structure on substrate. Large current densities in the metallic devices, beyond the Ohmic regime, can generate unintended anisotropic thermal gradients and voltages. AFM switching requires unequivocal detection of the AFM Néel vector before and after SOT switching.
Summary
Background
Limited data are available on the efficacy and safety of antiviral therapy in geriatric patients with chronic hepatitis C virus (HCV) infection.
Aim
To evaluate the efficacy and ...safety of pegylated interferon (pegIFN) plus ribavirin (RBV) therapy in geriatric HCV‐infected patients.
Methods
Ninety‐one geriatric patients (age ≥65 years; the elderly group) with HCV infection and 91 gender‐ and HCV genotype‐matched middle‐aged patients (age 50–64 years; the younger group) were assigned to receive weekly pegIFN injection plus weight‐based oral RBV for 24 weeks. The on‐ and off‐treatment virological responses were evaluated for treatment efficacy.
Results
In intention‐to‐treat analysis, the sustained virological response (SVR) rate was substantially decreased in the elderly patients (elderly group vs. younger group, 40.7% vs. 61.5%, respectively; P = 0.005). The SVR rate was significantly lower in geriatric patients than in middle‐aged patients with HCV genotype non‐1 (54.3% vs. 82.9%; P = 0.01), but the difference was not significant with HCV genotype 1 (32.1% vs. 48.2%; P = 0.083). Furthermore, the older patients infected with HCV genotype non‐1 who achieved a rapid virological response had a similar SVR rate to that of the younger patients. The withdrawal rate was 13.2% in the elderly group and 7.7% in the younger group.
Conclusions
Compared with middle‐aged patients, the therapeutic efficacy of pegylated interferon plus ribavirin therapy is lower in hepatitis C virus‐infected geriatric patients with an acceptable withdrawal rate. Considering prolonged lifespan in geriatric patients, we recommend treating geriatric hepatitis C virus‐infected patients who have significant hepatic fibrosis and no other health problems.
An ultimate goal of spintronics is to control magnetism via electrical means. One promising way is to utilize a current-induced spin-orbit torque (SOT) originating from the strong spin-orbit coupling ...in heavy metals and their interfaces to switch a single perpendicularly magnetized ferromagnetic layer at room temperature. However, experimental realization of SOT switching to date requires an additional in-plane magnetic field, or other more complex measures, thus severely limiting its prospects. Here we present a novel structure consisting of two heavy metals that delivers competing spin currents of opposite spin indices. Instead of just canceling the pure spin current and the associated SOTs as one expects and corroborated by the widely accepted SOTs, such devices manifest the ability to switch the perpendicular CoFeB magnetization solely with an in-plane current without any magnetic field. Magnetic domain imaging reveals selective asymmetrical domain wall motion under a current. Our discovery not only paves the way for the application of SOT in nonvolatile technologies, but also poses questions on the underlying mechanism of the commonly believed SOT-induced switching phenomenon.
Worldwide, some 240 million people have chronic hepatitis B virus (HBV), with the highest rates of infection in Africa and Asia. Our understanding of the natural history of HBV infection and the ...potential for therapy of the resultant disease is continuously improving. New data have become available since the previous APASL guidelines for management of HBV infection were published in 2012. The objective of this manuscript is to update the recommendations for the optimal management of chronic HBV infection. The 2015 guidelines were developed by a panel of Asian experts chosen by the APASL. The clinical practice guidelines are based on evidence from existing publications or, if evidence was unavailable, on the experts’ personal experience and opinion after deliberations. Manuscripts and abstracts of important meetings published through January 2015 have been evaluated. This guideline covers the full spectrum of care of patients infected with hepatitis B, including new terminology, natural history, screening, vaccination, counseling, diagnosis, assessment of the stage of liver disease, the indications, timing, choice and duration of single or combination of antiviral drugs, screening for HCC, management in special situations like childhood, pregnancy, coinfections, renal impairment and pre- and post-liver transplant, and policy guidelines. However, areas of uncertainty still exist, and clinicians, patients, and public health authorities must therefore continue to make choices on the basis of the evolving evidence. The final clinical practice guidelines and recommendations are presented here, along with the relevant background information.
Abstract
A supercurrent flowing in a superconductor meets no resistance. Yet an electric field may still be established within the superconductor in the presence of dissipative processes, such as ...vortex motion. Here we report the observation of a transverse voltage drop in superconducting
β-
Bi
2
Pd thin films. Unlike the Hall effect in general or in other superconductors, the sign of the observed transverse voltage does not depend on the external magnetic field. Instead, it is dictated by the broken inversion symmetry on the film interfaces. This anomalous transverse voltage, or transverse resistance, is indicative of a chirality that likely resonates with the topological surface states reported in
β-
Bi
2
Pd.
A prime category of superconducting materials in which to look for spin-triplet pairing and topological superconductivity are superconductors without inversion symmetry. It is predicted that the ...broken parity symmetry gives rise to an admixture of spin-triplet and spin-singlet pairing states. However, experimental confirmation of pairing mixing in any material remains elusive. In this work, we perform a phase-sensitive experiment to examine the pairing state of noncentrosymmetric superconductor α-BiPd. The Little-Parks effect observed in mesoscopic polycrystalline α-BiPd rings reveals the presence of half-integer magnetic flux quantization, which provides a decisive evidence for the spin-triplet pairing state. We find both half-quantum fluxes and integer-quantum fluxes of different proportions, consistent with the scenario of an admixture of singlet-triplet pairing.
Phase-sensitive measurements on a composite ring made of a superconductor of interest connected by a known singlet s-wave superconductor can unambiguously determine its pairing symmetry. In composite ...rings with epitaxial β-Bi_{2}Pd and s-wave Nb, we have observed half-integer-quantum flux when Nb is connected to the opposite crystalline ends of β-Bi_{2}Pd and integer-quantum flux when Nb is connected to the same crystalline ends of β-Bi_{2}Pd. With ascending temperature, the half-integer-flux quantization transits to integer-flux quantization, before the eventual loss of phase coherence. These findings point to odd-parity pairing symmetry in superconducting β-Bi_{2}Pd.
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