7,163 research outputs found
From Protecting the Heart to Improving Athletic Performance - the Benefits of Local and Remote Ischaemic Preconditioning
Remote Ischemic Preconditioning (RIPC) is a non-invasive cardioprotective intervention that involves brief cycles of limb ischemia and reperfusion. This is typically delivered by inflating and deflating a blood pressure cuff on one or more limb(s) for several cycles, each inflation-deflation being 3-5 min in duration. RIPC has shown potential for protecting the heart and other organs from injury due to lethal ischemia and reperfusion injury, in a variety of clinical settings. The mechanisms underlying RIPC are under intense investigation but are just beginning to be deciphered. Emerging evidence suggests that RIPC has the potential to improve exercise performance, via both local and remote mechanisms. This review discusses the clinical studies that have investigated the role of RIPC in cardioprotection as well as those studying its applicability in improving athletic performance, while examining the potential mechanisms involved
Uterine selection of human embryos at implantation
Human embryos frequently harbor large-scale complex chromosomal errors that impede normal development. Affected embryos may fail to implant although many first breach the endometrial epithelium and embed in the decidualizing stroma before being rejected via mechanisms that are poorly understood. Here we show that developmentally impaired human embryos elicit an endoplasmic stress response in human decidual cells. A stress response was also evident upon in vivo exposure of mouse uteri to culture medium conditioned by low-quality human embryos. By contrast, signals emanating from developmentally competent embryos activated a focused gene network enriched in metabolic enzymes and implantation factors. We further show that trypsin, a serine protease released by pre-implantation embryos, elicits Ca2+ signaling in endometrial epithelial cells. Competent human embryos triggered short-lived oscillatory Ca2+ fluxes whereas low-quality embryos caused a heightened and prolonged Ca2+ response. Thus, distinct positive and negative mechanisms contribute to active selection of human embryos at implantation
Defeating Paediatric Tuberculous Meningitis: Applying the WHO "Defeating Meningitis by 2030: Global Roadmap"
Children affected by tuberculous meningitis (TBM), as well as their families, have needs that lie at the intersections between the tuberculosis and meningitis clinical, research, and policy spheres. There is therefore a substantial risk that these needs are not fully met by either programme. In this narrative review article, we use the World Health Organization (WHO) “Defeating Meningitis by 2030: global roadmap” as a starting point to consider key goals and activities to specifically defeat TBM in children. We apply the five pillars outlined in the roadmap to describe how this approach can be adapted to serve children affected by TBM. The pillars are (i) prevention; (ii) diagnosis and treatment; (iii) surveillance; (iv) support and care for people affected by meningitis; and (v) advocacy and engagement. We conclude by calling for greater integration between meningitis and TB programmes at WHO and at national levels
Electronic depiction of magnetic origin in undoped and Fe doped TiO2-d epitaxial thin films
We have investigated the electronic and magnetic properties of the pulsed laser deposited epitaxial thin films of undoped and Fe doped (4 at. %) anatase TiO2-d by photoemission, magnetization measurements, and ab-initio band structure calculations. These films show room temperature magnetic ordering. It is observed that Fe ions hybridize with the oxygen vacancy induced Ti3+ defect states. Our study reveals the formation of local magnetic moment at Ti and Fe sites to be responsible for magnetic ordering. A finite density of states at the Fermi level in both undoped and Fe doped films is also observed, suggesting their degenerate semiconducting nature. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3640212]991
Matched sizes of activating and inhibitory receptor/ligand pairs are required for optimal signal integration by human Natural Killer cells
It has been suggested that receptor-ligand complexes segregate or co-localise within immune synapses according to their size, and this is important for receptor signaling. Here, we set out to test the importance of receptor-ligand complex dimensions for immune surveillance of target cells by human Natural Killer (NK) cells. NK cell activation is regulated by integrating signals from activating receptors, such as NKG2D, and inhibitory receptors, such as KIR2DL1. Elongating the NKG2D ligand MICA reduced its ability to trigger NK cell activation. Conversely, elongation of KIR2DL1 ligand HLA-C reduced its ability to inhibit NK cells. Whereas normal-sized HLA-C was most effective at inhibiting activation by normal-length MICA, only elongated HLA-C could inhibit activation by elongated MICA. Moreover, HLA-C and MICA that were matched in size co-localised, whereas HLA-C and MICA that were different in size were segregated. These results demonstrate that receptor-ligand dimensions are important in NK cell recognition, and suggest that optimal integration of activating and inhibitory receptor signals requires the receptor-ligand complexes to have similar dimensions
Molecular Mechanism of Action of Antimalarial Benzoisothiazolones: Species-Selective Inhibitors of the Plasmodium spp. MEP Pathway enzyme, IspD
The methylerythritol phosphate (MEP) pathway is an essential metabolic pathway found in malaria parasites, but absent in mammals, making it a highly attractive target for the discovery of novel and selective antimalarial therapies. Using high-throughput screening, we have identified 2-phenyl benzo[d]isothiazol-3(2H)-ones as species-selective inhibitors of Plasmodium spp. 2-C-methyl-D-erythritol-4-phosphate cytidyltransferase (IspD), the third catalytic enzyme of the MEP pathway. 2-Phenyl benzo[d]isothiazol-3(2H)-ones display nanomolar inhibitory activity against P. falciparum and P. vivax IspD and prevent the growth of P. falciparum in culture, with EC50 values below 400 nM. In silico modeling, along with enzymatic, genetic and crystallographic studies, have established a mechanism-of-action involving initial non-covalent recognition of inhibitors at the IspD binding site, followed by disulfide bond formation through attack of an active site cysteine residue on the benzo[d]isothiazol-3(2H)-one core. The species-selective inhibitory activity of these small molecules against Plasmodium spp. IspD and cultured parasites suggests they have potential as lead compounds in the pursuit of novel drugs to treat malaria
Gaze Stability for Liveness Detection
Spoofing attacks on biometric systems are one of the major impediments to their use for secure unattended applications. This paper explores features for face liveness detection based on tracking the gaze of the user. In the proposed approach, a visual stimulus is placed on the display screen, at apparently random locations, which the user is required to follow while their gaze is measured. This visual stimulus appears in such a way that it repeatedly directs the gaze of the user to specific positions on the screen. Features extracted from sets of collinear and colocated points are used to estimate the liveness of the user. Data is collected from genuine users tracking the stimulus with natural head/eye movements and impostors holding a photograph, looking through a 2D mask or replaying the video of a genuine user. The choice of stimulus and features are based on the assumption that natural head/eye coordination for directing gaze results in a greater accuracy and thus can be used to effectively differentiate between genuine and spoofing attempts. Tests are performed to assess the effectiveness of the system with these features in isolation as well as in combination with each other using score fusion techniques. The results from the experiments indicate the effectiveness of the proposed gaze-based features in detecting such presentation attacks
The Role of Speckle-Tracking Echocardiography in Predicting Mortality and Morbidity in Patients With Congenital Heart Disease: A Systematic Review and Meta-analysis
This is the final version. Available on open access from Elsevier via the DOI in this recordData Availability Statement:
The data underlying this article will be shared on reasonable request to the corresponding authorBACKGROUND: Speckle-tracking echocardiography (STE) is now routinely included in cardiac evaluations, but its role in predicting mortality and morbidity in congenital heart disease (CHD) is not well described. We conducted a systematic review to evaluate the prognostic value of STE in patients with CHD. METHODS: The EMBASE, Medline, Web of Science, Scopus, and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched from inception to January 2023 for terms related to all CHD, STE, and prognosis. Meta-analysis of association of right ventricle and left ventricle strain (RV Sl and LV Sl, respectively) with major adverse cardiovascular events (MACEs) was performed in atrial switch transposition of the great arteries (asTGA)/congenitally corrected TGA (ccTGA), tetralogy of Fallot (ToF), and congenital aortic stenosis (cAS)/bicuspid aortic valve (BAV). P-value combination analysis was additionally performed for all CHD groups. RESULTS: A total of 33 studies (30 cohorts, n = 8,619 patients, children, and adults) were included. Meta-analysis showed the following parameters as being associated with MACE: RV Sl in asTGA/ccTGA (hazard ratio [HR] = 1.1/%; CI, [1.03; 1.18]), RV Sl and LV Sl in ToF (HR = 1.14/%; CI, [1.03; 1.26] and HR = 1.14/%; CI, [1.08; 1.2], respectively), and LV Sl in cAS/BAV (HR = 1.19/%; CI, [1.15; 1.23]). The RV Sl and strain rate were associated with outcomes also in single ventricle/hypoplastic left heart syndrome (at all palliation stages except before Norwood stage 1) and LV Sl in Ebstein's anomaly. CONCLUSIONS: This systematic review and meta-analysis showed that biventricular strain and strain rate were associated with outcomes in a variety of CHD, highlighting the need for updated recommendations on the use of STE in the current guidelines, specific to disease types
The relation of steady evaporating drops fed by an influx and freely evaporating drops
We discuss a thin film evolution equation for a wetting evaporating liquid on
a smooth solid substrate. The model is valid for slowly evaporating small
sessile droplets when thermal effects are insignificant, while wettability and
capillarity play a major role. The model is first employed to study steady
evaporating drops that are fed locally through the substrate. An asymptotic
analysis focuses on the precursor film and the transition region towards the
bulk drop and a numerical continuation of steady drops determines their fully
non-linear profiles.
Following this, we study the time evolution of freely evaporating drops
without influx for several initial drop shapes. As a result we find that drops
initially spread if their initial contact angle is larger than the apparent
contact angle of large steady evaporating drops with influx. Otherwise they
recede right from the beginning
Allergic enterocolitis and protein-losing enteropathy as the presentations of manganese leak from an ingested disk battery: A case report
<p>Abstract</p> <p>Introduction</p> <p>Disk battery ingestions can lead to serious complications including airway or digestive tract perforation, blood vessel erosions, mediastinitis, and stricture formation.</p> <p>Case presentation</p> <p>We report a 20-month-old Caucasian child who developed eosinophilic enterocolitis and subsequent protein-losing enteropathy from manganese that leaked from a lithium disk battery. The disk battery was impacted in her esophagus for 10 days resulting in battery corrosion. We postulate that this patient's symptoms were due to a manganese leak from the 'retained' disk battery; this resulted in an allergic response in her gut and protein-losing enteropathy. Her symptoms improved gradually over the next 2 weeks with conservative management.</p> <p>Conclusion</p> <p>This is the first case report to highlight the potential complication of allergic enterocolitis and protein-losing enteropathy secondary to ingested manganese. Clinicians should be vigilant about this rare complication in managing patients with disk battery ingestions.</p
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