320 research outputs found
A Meta-learning based Generalizable Indoor Localization Model using Channel State Information
Indoor localization has gained significant attention in recent years due to
its various applications in smart homes, industrial automation, and healthcare,
especially since more people rely on their wireless devices for location-based
services. Deep learning-based solutions have shown promising results in
accurately estimating the position of wireless devices in indoor environments
using wireless parameters such as Channel State Information (CSI) and Received
Signal Strength Indicator (RSSI). However, despite the success of deep
learning-based approaches in achieving high localization accuracy, these models
suffer from a lack of generalizability and can not be readily-deployed to new
environments or operate in dynamic environments without retraining. In this
paper, we propose meta-learning-based localization models to address the lack
of generalizability that persists in conventionally trained DL-based
localization models. Furthermore, since meta-learning algorithms require
diverse datasets from several different scenarios, which can be hard to collect
in the context of localization, we design and propose a new meta-learning
algorithm, TB-MAML (Task Biased Model Agnostic Meta Learning), intended to
further improve generalizability when the dataset is limited. Lastly, we
evaluate the performance of TB-MAML-based localization against conventionally
trained localization models and localization done using other meta-learning
algorithms.Comment: 6 pages, 6 figures, submitted to IEEE GLOBECOM 202
Conformation-regulated mechanosensory control via titin domains in cardiac muscle
The giant filamentous protein titin is ideally positioned in the muscle sarcomere to sense mechanical stimuli and transform them into biochemical signals, such as those triggering cardiac hypertrophy. In this review, we ponder the evidence for signaling hotspots along the titin filament involved in mechanosensory control mechanisms. On the way, we distinguish between stress and strain as triggers of mechanical signaling events at the cardiac sarcomere. Whereas the Z-disk and M-band regions of titin may be prominently involved in sensing mechanical stress, signaling hotspots within the elastic I-band titin segment may respond primarily to mechanical strain. Common to both stress and strain sensor elements is their regulation by conformational changes in protein domains
Modelling of grinding mechanics : a review
Grinding is one of the most widely used material removal methods at the end of many process chains. Grinding force is related to almost all grinding parameters, which has a great influence on material removal rate, dimensional and shape accuracy, surface and subsurface integrity, thermodynamics, dynamics, wheel durability, and machining system deformation. Considering that grinding force is related to almost all grinding parameters, grinding force can be used to detect grinding wheel wear, energy calculation, chatter suppression, force control and grinding process simulation. Accurate prediction of grinding forces is important for optimizing grinding parameters and the structure of grinding machines and fixtures. Although there are substantial research papers on grinding mechanics, a comprehensive review on the modeling of grinding mechanics is still absent from the literature. To fill this gap, this work reviews and introduces theoretical methods and applications of mechanics in grinding from the aspects of modeling principles, limitations and possible future trendencies
Final 5-year clinical and echocardiographic results for treatment of severe aortic stenosis with a self-expanding bioprosthesis from the ADVANCE Study.
Aims: The ADVANCE study was designed to evaluate the safety and effectiveness of transcatheter aortic valve implantation (TAVI) with a self-expanding bioprosthesis in real-world patients with symptomatic, severe aortic stenosis at high surgical risk for valve replacement. Methods and results: Study participants were enrolled from 44 experienced centres in 12 countries. Patient eligibility, treatment approach, and choice of anaesthesia were determined by the local Heart Team. The study was 100% monitored, and adverse events were adjudicated by an independent clinical events committee using Valve Academic Research Consortium (VARC-1) criteria. There were 1015 patients enrolled with 996 attempted TAVI procedures. Mean age was 81 years, and mean logistic EuroSCORE was 19.3 ± 12.3%. Five-year follow-up was available on 465 (46.7%) patients. At 5 years, the rate of all-cause mortality was 50.7% (95% confidence interval: 46.7%, 54.5%), and the rate of major stroke was 5.4%. Haemodynamic measures remained consistent for paired patients with a mean aortic valve gradient of 8.8 ± 4.4 mmHg (n = 198) and an effective orifice area of 1.7 ± 0.4 cm2 (n = 123). Aortic regurgitation (AR) decreased over time and among paired patients dropped from 12.8% to 8.0% moderate AR at 5 years (n = 125). Of the 860 patients with echocardiographic data or a reintervention after 30 days, there were 22 (2.6%) patients meeting the VARC-2 criteria for valve dysfunction and 10 (1.2%) patients with a reintervention >30 days. Conclusion: Five-year results in real-world, elderly, high-risk patients undergoing TAVI with a self-expanding bioprosthesis provided evidence for continued valve durability with low rates of reinterventions and haemodynamic valve dysfunction. Trial registration: ClinicalTrials.gov, NCT01074658
KiDS+VIKING+GAMA:Testing semi-analytic models of galaxy evolution with galaxy-galaxy-galaxy lensing
Several semi-analytic models (SAMs) try to explain how galaxies form, evolve
and interact inside the dark matter large-scale structure. These SAMs can be
tested by comparing their predictions for galaxy-galaxy-galaxy-lensing (G3L),
which is weak gravitational lensing around galaxy pairs, with observations. We
evaluate the SAMs by Henriques et al. (2015; H15) and by Lagos et al. (2012;
L12), implemented in the Millennium Run, by comparing their predictions for G3L
to observations at smaller scales than previous studies and also for pairs of
lens galaxies from different populations. We compare the G3L signal predicted
by the SAMs to measurements in the overlap of the Galaxy And Mass Assembly
survey (GAMA), the Kilo-Degree Survey (KiDS), and the VISTA Kilo-degree
Infrared Galaxy survey (VIKING), splitting lens galaxies into two colour and
five stellar-mass samples. Using an improved G3L estimator, we measure the
three-point correlation of the matter distribution for mixed lens pairs with
galaxies from different samples, and unmixed lens pairs with galaxies from the
same sample. Predictions by the H15 SAM agree with the observations for all
colour-selected and all but one stellar-mass-selected sample with 95%
confidence. Deviations occur for lenses with stellar masses below
at scales below .
Predictions by the L12 SAM for stellar-mass selected samples and red galaxies
are significantly higher than observed, while the predicted signal for blue
galaxy pairs is too low. The L12 SAM predicts more pairs of small stellar-mass
and red galaxies than the H15 SAM and the observations, as well as fewer pairs
of blue galaxies. Likely explanations are different treatments of environmental
effects by the SAMs and different models of the initial mass function. We
conclude that G3L provides a stringent test for models of galaxy formation and
evolution.Comment: 14 pages, 8 figures, replaced with version accepted to Astronomy &
Astrophysics after considering referees comment
Matrin3: connecting gene expression with the nuclear matrix.
As indicated by its name, Matrin3 was discovered as a component of the nuclear matrix, an insoluble fibrogranular network that structurally organizes the nucleus. Matrin3 possesses both DNA- and RNA-binding domains and, consistent with this, has been shown to function at a number of stages in the life cycle of messenger RNAs. These numerous activities indicate that Matrin3, and indeed the nuclear matrix, do not just provide a structural framework for nuclear activities but also play direct functional roles in these activities. Here, we review the structure, functions, and molecular interactions of Matrin3 and of Matrin3-related proteins, and the pathologies that can arise upon mutation of Matrin3. WIREs RNA 2016, 7:303-315. doi: 10.1002/wrna.1336 For further resources related to this article, please visit the WIREs website.We thank Clare Gooding and Dipen Rajgor for critical comments on the manuscript. Work in the CWJS lab on Matrin3 is funded by a grant from the Wellcome Trust (092900). JA was funded by a Boehringer Ingelheim Fonds studentship.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/wrna.133
Ischemia-Reperfusion Injury and Pregnancy Initiate Time-Dependent and Robust Signs of Up-Regulation of Cardiac Progenitor Cells
To explore how cardiac regeneration and cell turnover adapts to disease, different forms of stress were studied for their effects on the cardiac progenitor cell markers c-Kit and Isl1, the early cardiomyocyte marker Nkx2.5, and mast cells. Adult female rats were examined during pregnancy, after myocardial infarction and ischemia-reperfusion injury with/out insulin like growth factor-1(IGF-1) and hepatocyte growth factor (HGF). Different cardiac sub-domains were analyzed at one and two weeks post-intervention, both at the mRNA and protein levels. While pregnancy and myocardial infarction up-regulated Nkx2.5 and c-Kit (adjusted for mast cell activation), ischemia-reperfusion injury induced the strongest up-regulation which occurred globally throughout the entire heart and not just around the site of injury. This response seems to be partly mediated by increased endogenous production of IGF-1 and HGF. Contrary to c-Kit, Isl1 was not up-regulated by pregnancy or myocardial infarction while ischemia-reperfusion injury induced not a global but a focal up-regulation in the outflow tract and also in the peri-ischemic region, correlating with the up-regulation of endogenous IGF-1. The addition of IGF-1 and HGF did boost the endogenous expression of IGF and HGF correlating to focal up-regulation of Isl1. c-Kit expression was not further influenced by the exogenous growth factors. This indicates that there is a spatial mismatch between on one hand c-Kit and Nkx2.5 expression and on the other hand Isl1 expression. In conclusion, ischemia-reperfusion injury was the strongest stimulus with both global and focal cardiomyocyte progenitor cell marker up-regulations, correlating to the endogenous up-regulation of the growth factors IGF-1 and HGF. Also pregnancy induced a general up-regulation of c-Kit and early Nkx2.5+ cardiomyocytes throughout the heart. Utilization of these pathways could provide new strategies for the treatment of cardiac disease
Structure of a Burkholderia pseudomallei Trimeric Autotransporter Adhesin Head
Pathogenic bacteria adhere to the host cell surface using a family of outer membrane proteins called Trimeric Autotransporter Adhesins (TAAs). Although TAAs are highly divergent in sequence and domain structure, they are all conceptually comprised of a C-terminal membrane anchoring domain and an N-terminal passenger domain. Passenger domains consist of a secretion sequence, a head region that facilitates binding to the host cell surface, and a stalk region.Pathogenic species of Burkholderia contain an overabundance of TAAs, some of which have been shown to elicit an immune response in the host. To understand the structural basis for host cell adhesion, we solved a 1.35 A resolution crystal structure of a BpaA TAA head domain from Burkholderia pseudomallei, the pathogen that causes melioidosis. The structure reveals a novel fold of an intricately intertwined trimer. The BpaA head is composed of structural elements that have been observed in other TAA head structures as well as several elements of previously unknown structure predicted from low sequence homology between TAAs. These elements are typically up to 40 amino acids long and are not domains, but rather modular structural elements that may be duplicated or omitted through evolution, creating molecular diversity among TAAs.The modular nature of BpaA, as demonstrated by its head domain crystal structure, and of TAAs in general provides insights into evolution of pathogen-host adhesion and may provide an avenue for diagnostics
Titin-truncating variants affect heart function in disease cohorts and the general population
Titin-truncating variants (TTNtv) commonly cause dilated cardiomyopathy (DCM). TTNtv are also encountered in ~1% of the general population, where they may be silent, perhaps reflecting allelic factors. To better understand TTNtv, we integrated TTN allelic series, cardiac imaging and genomic data in humans and studied rat models with disparate TTNtv. In patients with DCM, TTNtv throughout titin were significantly associated with DCM. Ribosomal profiling in rat showed the translational footprint of premature stop codons in Ttn, TTNtv-position-independent nonsense-mediated degradation of the mutant allele and a signature of perturbed cardiac metabolism. Heart physiology in rats with TTNtv was unremarkable at baseline but became impaired during cardiac stress. In healthy humans, machine-learning-based analysis of high-resolution cardiac imaging showed TTNtv to be associated with eccentric cardiac remodeling. These data show that TTNtv have molecular and physiological effects on the heart across species, with a continuum of expressivity in health and disease
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