The spin-orbit coupling relating the electron spin and momentum allows for spin generation, detection and manipulation. It thus fulfils the three basic functions of the spin field-effect transistor. ...However, the spin Hall effect in bulk germanium is too weak to produce spin currents, whereas large Rashba effect at Ge(111) surfaces covered with heavy metals could generate spin-polarized currents. The Rashba spin splitting can actually be as large as hundreds of meV. Here we show a giant spin-to-charge conversion in metallic states at the Fe/Ge(111) interface due to the Rashba coupling. We generate very large charge currents by direct spin pumping into the interface states from 20 K to room temperature. The presence of these metallic states at the Fe/Ge(111) interface is demonstrated by first-principles electronic structure calculations. By this, we demonstrate how to take advantage of the spin-orbit coupling for the development of the spin field-effect transistor.
Adjunctive glucocorticoids are widely used to treat human immunodeficiency virus (HIV)-associated tuberculous meningitis despite limited data supporting their safety and efficacy.
We conducted a ...double-blind, randomized, placebo-controlled trial involving HIV-positive adults (≥18 years of age) with tuberculous meningitis in Vietnam and Indonesia. Participants were randomly assigned to receive a 6-to-8-week tapering course of either dexamethasone or placebo in addition to 12 months of antituberculosis chemotherapy. The primary end point was death from any cause during the 12 months after randomization.
A total of 520 adults were randomly assigned to receive either dexamethasone (263 participants) or placebo (257 participants). The median age was 36 years; 255 of 520 participants (49.0%) had never received antiretroviral therapy, and 251 of 484 participants (51.9%) with available data had a baseline CD4 count of 50 cells per cubic millimeter or less. Six participants withdrew from the trial, and five were lost to follow-up. During the 12 months of follow-up, death occurred in 116 of 263 participants (44.1%) in the dexamethasone group and in 126 of 257 participants (49.0%) in the placebo group (hazard ratio, 0.85; 95% confidence interval, 0.66 to 1.10; P = 0.22). Prespecified analyses did not reveal a subgroup that clearly benefited from dexamethasone. The incidence of secondary end-point events, including cases of immune reconstitution inflammatory syndrome during the first 6 months, was similar in the two trial groups. The numbers of participants with at least one serious adverse event were similar in the dexamethasone group (192 of 263 participants 73.0%) and the placebo group (194 of 257 participants 75.5%) (P = 0.52).
Among HIV-positive adults with tuberculous meningitis, adjunctive dexamethasone, as compared with placebo, did not confer a benefit with respect to survival or any secondary end point. (Funded by the Wellcome Trust; ACT HIV ClinicalTrials.gov number, NCT03092817.).
Topological insulators (TIs) like Bi2Se3 are a class of material with topologically protected surface states in which spin-momentum locking may enable spin-polarized and defect-tolerant transport. In ...this work, we achieved the epitaxial growth of Bi2Se3 thin films on germanium, which is a key material for microelectronics. Germanium also exhibits interesting properties with respect to the electron spin such as a spin diffusion length of several micrometers at room temperature. By growing Bi2Se3 on germanium, we aim at combining the long spin diffusion length of Ge with the spin-momentum locking at the surface of Bi2Se3. We first performed a thorough structural analysis of Bi2Se3 films using electron and x-ray diffraction as well as atomic force microscopy. Then, magnetotransport measurements at low temperature showed the signature of weak antilocalization as a result of two-dimensional transport in the presence of spin-orbit coupling. We interpret our results as the signature of magnetotransport in a single strongly coupled coherent channel in the presence of surface to bulk scattering. Interestingly, the magnetotransport measurements also point out that the conduction channel can be tuned between the Bi2Se3 film and the Ge layer underneath by means of the bias voltage or the applied magnetic field. This result suggests that the Bi2Se3/Ge junction is a promising candidate for tuning spin-related phenomena at interfaces between TIs and semiconductors.
Spin-charge interconversion (SCI) phenomena have attracted a growing interest in the field of spintronics as a means to detect spin currents or manipulate the magnetization of ferromagnets. The key ...ingredients to exploit these assets are a large conversion efficiency, the scalability down to the nanometer scale, and the integrability with optoelectronic and spintronic devices. Here, we show that, when an ultrathin Bi film is epitaxially grown on a Ge(111) substrate, quantum size effects arising in nanometric Bi islands drastically boost the SCI efficiency, even at room temperature. Using x-ray diffraction, scanning tunneling microscopy, and spin- and angle-resolved photoemission, we obtain a clear picture of the film morphology, crystal, and electronic structures. We then directly probe SCI with three different techniques: magneto-optical Kerr effect to detect the charge-to-spin conversion generated by the Rashba-Edelstein effect (REE), optical spin orientation, and spin pumping to generate spin currents and measure the spin-to-charge conversion generated by the inverse Rashba-Edelstein effect (IREE). The three techniques show a sizable SCI only for 1–3-nm-thick Bi films corresponding to the presence of bismuth nanocrystals at the surface of germanium. Due to three-dimensional quantum confinement, those nanocrystals exhibit a highly resistive volume separating metallic surfaces where SCI takes place by (I)REE. As the film size increases, the Bi film becomes continuous and semimetallic leading to the cancellation of SCIs occurring at opposite surfaces, resulting in an average SCI that progressively decreases and disappears. These results pave the way for the exploitation of quantum size effects in spintronics.
•Parental stress was significantly related to maternal sensitivity.•Mother’s report of baby’s behavior and temperament was related to interactive quality.•Mother’s perception of baby not meeting her ...expectations related to sensitivity.•Major depression –in pregnancy or postpartum- had no effect on maternal sensitivity.•Fetal attachment did not predict sensitivity, intrusiveness and positive regard.
The current study aimed to examine the impact of maternal depression, maternal fetal attachment (MFA) and parenting stress on maternal sensitivity, intrusiveness and positive regard for the child with a sample of 36 low-income, mothers-infant dyads that were followed from pregnancy through the first year postpartum. Maternal depression and parenting stress were expected to have a negative impact on maternal sensitivity, intrusiveness and positive regard, while high MFA was hypothesized to have a positive impact on these three outcomes. Our data provide partial support for our hypotheses. Findings from this study add to the literature by examining the stability of the maternal prenatal and postpartum bond with her infant as well as by looking at the impact of parenting stress on maternal behaviors and processes that may lead to later attachment security differences, such as maternal sensitivity and responsiveness.
An imbalance between neutrophil-derived proteases and extracellular inhibitors is widely regarded as an important pathogenic mechanism for lung injury. Despite intense efforts over the last three ...decades, attempts to develop small-molecule inhibitors for neutrophil elastase have failed in the clinic. Here we discover an intrinsic self-cleaving property of mouse neutrophil elastase that interferes with the action of elastase inhibitors. We show that conversion of the single-chain (sc) into a two-chain (tc) neutrophil elastase by self-cleavage near its S1 pocket altered substrate activity and impaired both inhibition by endogenous α-1-antitrypsin and synthetic small molecules. Our data indicate that autoconversion of neutrophil elastase decreases the inhibitory efficacy of natural α-1-antitrypsin and small-molecule inhibitors, while retaining its pathological potential in an experimental mouse model. The so-far overlooked occurrence and properties of a naturally occurring tc-form of neutrophil elastase necessitates the redesign of small-molecule inhibitors that target the sc-form as well as the tc-form of neutrophil elastase.
Recent advances in assembling Carbon NanoTubes (CNTs) into macrostructures with outstanding properties, such as high tensile strength, high conductivity and porosity, and strong corrosive resistance, ...have underpinned potentially novel applications. For example, in advanced electronics, bioengineering and nanomechanics. This paper focuses on the development of (i) the piezoresistive polydimethylsiloxane-CNT (PDMS-CNT) composite membrane, and (ii) the thermo-resistive CNT hotwire using a technique of producing highly aligned CNT yarns and films. Our experimental results show that while PDMS-CNT films possess an outperformed gauge factor (10.7) compared with ones of CNT films in recent publications and several metals, a clear linear relationship of the resistance
versus
the temperature for a hotwire using CNT yarn is observed. Hence, the work supplies valuable evidence in the use of CNT films and yarns in several potential applications as thermal sensing elements and anemometric hotwires, respectively.
Recent advances in assembling Carbon NanoTubes (CNTs) into macrostructures with outstanding properties, such as high tensile strength, high conductivity and porosity, and strong corrosive resistance, have underpinned potentially novel applications.
In this paper, we report the numerical and experimental study of a valveless microblower actuated by a lead zirconate titanate (PZT) diaphragm. The blower is numerically studied using the open source ...software OpenFOAM for the first time. As part of the study, we further developed a lumped model to describe the response of the blower to the applied frequency on the diaphragm. The model parameters were obtained based on the geometry of the blower and the diaphragm material. The response of the blower obtained by the model was in close agreement with the experimental data that is archived from the prototype consisting of inexpensive audio electronic components. The flow rate of the device can be up to 0.7 l/m and the developed back pressure is 300Pa. Our study is useful for the development of an air generator applicable in health science, for energy applications, and integrated fluidic systems.
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