400 research outputs found

    Room temperature spin-orbit torque switching induced by a topological insulator

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    Recent studies on the magneto-transport properties of topological insulators (TI) have attracted great attention due to the rich spin-orbit physics and promising applications in spintronic devices. Particularly the strongly spin-moment coupled electronic states have been extensively pursued to realize efficient spin-orbit torque (SOT) switching. However, so far current-induced magnetic switching with TI has only been observed at cryogenic temperatures. It remains a controversial issue whether the topologically protected electronic states in TI could benefit spintronic applications at room temperature. In this work, we report full SOT switching in a TI/ferromagnet bilayer heterostructure with perpendicular magnetic anisotropy at room temperature. The low switching current density provides a definitive proof on the high SOT efficiency from TI. The effective spin Hall angle of TI is determined to be several times larger than commonly used heavy metals. Our results demonstrate the robustness of TI as an SOT switching material and provide a direct avenue towards applicable TI-based spintronic devices

    Forgiving you is hard, but forgetting seems easy: can forgiveness facilitate forgetting?

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    Forgiveness is considered to play a key role in the maintenance of social relationships, the avoidance of unnecessary conflict, and the ability to move forward with one's life. But why is it that some people find it easier to forgive and forget than others? In the current study, we explored the supposed relationship between forgiveness and forgetting. In an initial session, 30 participants imagined that they were the victim in a series of hypothetical incidents and indicated whether or not they would forgive the transgressor. Following a standard think/no-think procedure, in which participants were trained to think or not to think about some of these incidents, more forgetting was observed for incidents that had been forgiven following no-think instructions compared with either think or baseline instructions. In contrast, no such forgetting effects emerged for incidents that had not previously been forgiven. These findings have implications for goal-directed forgetting and the relationship between forgiveness and memory

    Transcatheter Aortic Valve Replacement Optimization Strategies: Cusp Overlap, Commissural Alignment, Sizing, and Positioning

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    As transcatheter aortic valve replacement (TAVR) rapidly expands to younger patients and those at low surgical risk, there is a compelling need to identify patients at increased risk of post-procedural complications, such as paravalvular leak, prosthesis–patient mismatch, and conduction abnormalities. This review highlights the incidence and risk factors of these procedural complications, and focuses on novel methods to reduce them by using newer generation transcatheter heart valves and the innovative cusp-overlap technique, which provides optimal fluoroscopic imaging projection to allow for precise implantation depth which minimizes interaction with the conduction system. Preserving coronary access after TAVR is another important consideration in younger patients. This paper reviews the significance of commissural alignment to allow coronary cannulation after TAVR and discusses recently published data on modified delivery techniques to improve commissural alignment

    Correction to: Novel mutation G324C in WNT1 mapped in a large Pakistani family with severe recessively inherited Osteogenesis Imperfecta

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    In the original publication of this article [1], there are two errors in the article which the cDNA position of the pathogenic variant WNT1 p.Gly324Cys should be c.970G>T instead of c.1168G>T

    Serum hepatocyte growth factor is associated with small vessel disease in Alzheimer's dementia

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    Background: While hepatocyte growth factor (HGF) is known to exert cell growth, migration and morphogenic effects in various organs, recent studies suggest that HGF may also play a role in synaptic maintenance and cerebrovascular integrity. Although increased levels of HGF have been reported in brain and cerebrospinal fluid (CSF) samples of patients with Alzheimer's disease (AD), it is unclear whether peripheral HGF may be associated with cerebrovascular disease (CeVD) and dementia. In this study, we examined the association of baseline serum HGF with neuroimaging markers of CeVD in a cohort of pre-dementia (cognitive impaired no dementia, CIND) and AD patients. Methods: Serum samples from aged, Non-cognitively impaired (NCI) controls, CIND and AD subjects were measured for HGF levels. CeVD (cortical infarcts, microinfarcts, lacunes, white matter hyperintensities (WMH) and microbleeds) were assessed by magnetic resonance imaging (MRI). Results: After controlling for covariates, higher levels of HGF were associated with both CIND and AD. Among the different CeVD MRI markers in CIND and AD, only small vessel disease, but not large vessel disease markers were associated with higher HGF levels. Conclusion: Serum HGF may be a useful peripheral biomarker for small vessel disease in subjects with cognitive impairment and AD

    Mixed-location cerebral microbleeds as a biomarker of neurodegeneration in a memory clinic population

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    Cerebral microbleeds (CMBs) in the lobar and deep locations are associated with two distinct pathologies: cerebral amyloid angiopathy and hypertensive arteriopathy. However, the role of mixed-location CMBs in neurodegeneration remains unexplored. We investigated the associations between strictly lobar, strictly deep and mixed-location CMBs with markers of neurodegeneration. This study recruited 477 patients from a memory clinic who underwent 3T MRI scans. CMBs were categorized into strictly lobar, strictly deep and mixed-location. Cortical thickness, white matter volume and subcortical structural volumes were quantified using Free-Surfer. Linear regression models were performed to assess the association between CMBs and cerebral atrophy, and the mean difference (β) and 95% confidence intervals (CIs) were reported. In the regression analyses, mixed-location CMBs were associated with smaller cortical thickness of limbic region [β=-0.01; 95% CI=-0.02,-0.00, p=0.007) as well as with smaller accumbens volume [β=-0.01; 95% CI=-0.02,-0.00, p=0.004) and presubiculum region of hippocampus [β=-0.01; 95% CI=-0.02,-0.00, p=0.002). Strictly lobar CMBs were associated with smaller total white matter volume [β=-0.03; 95% CI=-0.04,-0.01, p<0.001] and with region specific white mat

    Does malaria during pregnancy affect the newborn?

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    Objective: To investigate the effect of malarial infection during pregnancy on the newborn.Methods: A retrospective cohort study was conducted at The Aga Khan University Hospital (AKUH), Karachi, using in-patient hospital records over an 11-year period from 1988 to 1999. The incidence of preterm delivery, low birth weight (LBW) and intrauterine growth retardation (IUGR) in 29 pregnant women with malaria, was compared with that in 66 selected pregnant women without malaria, who delivered at the AKUH during the same time period.Results: Pregnant women with malaria had a 3.1 times greater risk of preterm labor (p=0.14). They were more likely to be anaemic compared to women without malaria (RR=2.9, 95% CI=1.6-5.4) and had a significantly lower mean haemoglobin level (p=0.0001). Maternal malaria was significantly associated with LBW babies (p=0.001). The mean birth weight of infants born to pregnant women with malaria was 461 g less (p=0.0005). No significant association was, however, found between malarial infection during pregnancy and IUGR (p=0.33).CONCLUSION: Malarial infection during pregnancy is associated with poor maternal and fetal outcome. It is significantly associated with maternal anaemia and LBW infants. Appropriate measures must, therefore, be taken to prevent malaria during pregnancy, especially in endemic areas

    Consolidating Literature for Images Compression and Its Techniques

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    With the proliferation of readily available image content, image compression has become a topic of considerable importance. As, rapidly increase of digital imaging demand, storage capability aspect should be considered. Therefore, image compression refers to reducing the size of image for minimizing storage without harming the image quality. Thus, an appropriate technique is needed for image compression for saving capacity as well as not losing valuable information. This paper consolidates literature whose characteristics have focused on image compression, thresholding algorithms, quantization algorithms. Later, related research on these areas are presented
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