1,364 research outputs found
Learning a Physical Activity Classifier for a Low-power Embedded Wrist-located Device
This article presents and evaluates a novel algorithm for learning a physical
activity classifier for a low-power embedded wrist-located device. The overall
system is designed for real-time execution and it is implemented in the
commercial low-power System-on-Chips nRF51 and nRF52. Results were obtained
using a database composed of 140 users containing more than 340 hours of
labeled raw acceleration data. The final precision achieved for the most
important classes, (Rest, Walk, and Run), was of 96%, 94%, and 99% and it
generalizes to compound activities such as XC skiing or Housework. We conclude
with a benchmarking of the system in terms of memory footprint and power
consumption.Comment: Submitted to the 2018 IEEE International Conference on Biomedical and
Health Informatic
Respiratory and cardiac monitoring at night using a wrist wearable optical system
Sleep monitoring provides valuable insights into the general health of an
individual and helps in the diagnostic of sleep-derived illnesses.
Polysomnography, is considered the gold standard for such task. However, it is
very unwieldy and therefore not suitable for long-term analysis. Here, we
present a non-intrusive wearable system that, by using photoplethysmography, it
can estimate beat-to-beat intervals, pulse rate, and breathing rate reliably
during the night. The performance of the proposed approach was evaluated
empirically in the Department of Psychology at the University of Fribourg. Each
participant was wearing two smart-bracelets from Ava as well as a complete
polysomnographic setup as reference. The resulting mean absolute errors are
17.4 ms (MAPE 1.8%) for the beat-to-beat intervals, 0.13 beats-per-minute (MAPE
0.20%) for the pulse rate, and 0.9 breaths-per-minute (MAPE 6.7%) for the
breath rate.Comment: Submitted to the 40th International Conference of the IEEE
Engineering in Medicine and Biology Society (EMBC
FCMpy: A Python Module for Constructing and Analyzing Fuzzy Cognitive Maps
FCMpy is an open source package in Python for building and analyzing Fuzzy
Cognitive Maps. More specifically, the package allows 1) deriving fuzzy causal
weights from qualitative data, 2) simulating the system behavior, 3) applying
machine learning algorithms (e.g., Nonlinear Hebbian Learning, Active Hebbian
Learning, Genetic Algorithms and Deterministic Learning) to adjust the FCM
causal weight matrix and to solve classification problems, and 4) implementing
scenario analysis by simulating hypothetical interventions (i.e., analyzing
what-if scenarios).Comment: 22 pages, 9 Figure
Detection of Beat-to-Beat Intervals from Wrist Photoplethysmography in Patients with Sinus Rhythm and Atrial Fibrillation after Surgery
Wrist photoplethysmography (PPG) allows unobtrusive monitoring of the heart
rate (HR). PPG is affected by the capillary blood perfusion and the pumping
function of the heart, which generally deteriorate with age and due to presence
of cardiac arrhythmia. The performance of wrist PPG in monitoring beat-to-beat
HR in older patients with arrhythmia has not been reported earlier. We
monitored PPG from wrist in 18 patients recovering from surgery in the post
anesthesia care unit, and evaluated the inter-beat interval (IBI) detection
accuracy against ECG based R-to-R intervals (RRI). Nine subjects had sinus
rhythm (SR, 68.0y10.2y, 6 males) and nine subjects had atrial fibrillation
(AF, 71.3y7.8y, 4 males) during the recording. For the SR group, 99.44% of
the beats were correctly identified, 2.39% extra beats were detected, and the
mean absolute error (MAE) was 7.34 ms. For the AF group, 97.49% of the
heartbeats were correctly identified, 2.26% extra beats were detected, and the
MAE was 14.31 ms. IBI from the PPG were hence in close agreement with the ECG
reference in both groups. The results suggest that wrist PPG provides a
comfortable alternative to ECG and can be used for long-term monitoring and
screening of AF episodes.Comment: Submitted to the 2018 IEEE International Conference on Biomedical and
Health Informatic
Methodology to address radioprotection and safety issues in the IFMIF/EVEDA accelerator prototype
In the IFMIF/EVEDA accelerator prototype, deuterons (with energies up to 9 MeV) interact with the materials of the accelerator components due to beam losses and in the beam dump, where the beam is stopped. The productions of neutrons/photons together with radioactive inventories due to deuteron-induced reactions are some major issues for radioprotection and safety assessment. Here, we will focus on the proposal of a computational approach able to simulate deuteron transport and evaluate deuteron interactions and production of secondary particles with acceptable precision. Current Monte Carlo codes, such as MCNPX or PHITS, when applied for deuteron transport calculation, use built-in semi-analytical models to describe deuteron interactions. These models are found unreliable in predicting neutron and photon generated by low energy deuterons, typically present in the IFMIF/EVEDA prototype accelerator. In this context, a new computational methodological approach is proposed based on the use of an extended version of current MC codes capable to use evaluated deuteron libraries for neutron (and gamma) production. The TALYS nuclear reaction code is found to be an interesting potential candidate to produce the evaluated data for double-differential neutron and photon emission cross sections for incident deuterons in the energy range of interest for IFMIF/EVEDA applications. The recently-released deuteron Talys-based Evaluated Nuclear Data Library, TENDL-2009, is considered a good starting point in the road to achieve deuteron data files of enough quality for deuteron transport problems in EVEDA. Unfortunately, current Monte Carlo transport codes are not able to handle light ion libraries except for protons. To overcome this drawback the MCNPX code has been extended to handle deuteron (also triton, helion and alpha) nuclear data libraries. In this new extended MCNPX version called MCUNED, a new variance reduction technique has also been implemented for the production of secondary particles induced by light ions nuclear reactions, which allow reducing drastically the computing time needed in transport and nuclear response function calculations. Verification of these new capabilities for Monte 2 Carlo simulation of deuteron transport and secondary products generation included in MCUNED is successfully achieved. The existence of the MCUNED code allows us for the first time testing the deuteron crosssection TENDL package by simulation of integral experiments. Some preliminary efforts are addressed to compare existing experimental data on thick target neutron yields for Copper with those computed by the MCUNED code using TENDL cross sections
Osteonecrosis of the femoral head safely healed with autologous, expanded, bone marrow-derived mesenchymal stromal cells in a multicentric trial with minimum 5 years follow-up
Background: Osteonecrosis (ON) of the femoral head represents a potentially severe
disease of the hip where the lack of bone regeneration may lead to femoral head collapse and secondary osteoarthritis, with serious pain and disability. The aim of this European, multicentric clinical trial
was to prove safety and early efficacy to heal early femoral head ON in patients through minimally
invasive surgical implantation of autologous mesenchymal stromal cells (MSC) expanded from
bone marrow (BM) under good manufacturing practices (GMP). Methods: Twenty-two patients with
femoral head ON (up to ARCO 2C) were recruited and surgically treated in France, Germany, Italy
and Spain with BM-derived, expanded autologous MSC (total dose 140 million MSC in 7 mL). The
investigational advanced therapy medicinal product (ATMP) was expanded from BM under the
same protocol in all four countries and approved by each National Competent Authority. Patients
were followed during two years for safety, based on adverse events, and for efficacy, based on clinical
assessment (pain and hip score) and imaging (X-rays and MRIs). Patients were also reviewed after
5 to 6 years at latest follow-up for final outcome. Results: No severe adverse event was recalled as
related to the ATMP. At 12 months, 16/20 per protocol and 16/22 under intention-to-treat (2 drop-out
at 3 and 5 months) maintained head sphericity and showed bone regeneration. Of the 4 hips with ON progression, 3 required total hip replacement (THR). At 5 years, one patient (healed at 2 years
visit) was not located, and 16/21 showed no progression or THR, 4/21 had received THR (all in the
first year) and 1 had progressed one stage without THR. Conclusions: Expanded MSCs implantation was safe. Early efficacy was confirmed in 80% of cases under protocol at 2 years. At 5 years, the overall results were maintained and 19% converted to THR, all in the first yearThe research leading to these results has received funding from the European Research
Council under the European Union’s Seventh Framework Programme (FP7/FP7-HEALTH-2009): REBORNE Project, Grant Agreement 241876. Work in EFS and stromalab was also supported by the Agence Nationale pour la Recherche for support of the national infrastructure: “ECELLFRANCE
The Spatial Distribution of Dust and Stellar Emission of the Magellanic Clouds
We study the emission by dust and stars in the Large and Small Magellanic
Clouds, a pair of low-metallicity nearby galaxies, as traced by their spatially
resolved spectral energy distributions (SEDs). This project combines Herschel
Space Observatory PACS and SPIRE far-infrared photometry with other data at
infrared and optical wavelengths. We build maps of dust and stellar luminosity
and mass of both Magellanic Clouds, and analyze the spatial distribution of
dust/stellar luminosity and mass ratios. These ratios vary considerably
throughout the galaxies, generally between the range and .
We observe that the dust/stellar ratios depend on the interstellar medium (ISM)
environment, such as the distance from currently or previously star-forming
regions, and on the intensity of the interstellar radiation field (ISRF). In
addition, we construct star formation rate (SFR) maps, and find that the SFR is
correlated with the dust/stellar luminosity and dust temperature in both
galaxies, demonstrating the relation between star formation, dust emission and
heating, though these correlations exhibit substantial scatter.Comment: 15 pages, 18 figures; ApJ, in press; version published in the journal
will have higher-resolution figure
Active Fragments from Pro- and Antiapoptotic BCL-2 Proteins Have Distinct Membrane Behavior Reflecting Their Functional Divergence
BACKGROUND: The BCL-2 family of proteins includes pro- and antiapoptotic members acting by controlling the permeabilization of mitochondria. Although the association of these proteins with the outer mitochondrial membrane is crucial for their function, little is known about the characteristics of this interaction. METHODOLOGY/PRINCIPAL FINDINGS: Here, we followed a reductionist approach to clarify to what extent membrane-active regions of homologous BCL-2 family proteins contribute to their functional divergence. Using isolated mitochondria as well as model lipid Langmuir monolayers coupled with Brewster Angle Microscopy, we explored systematically and comparatively the membrane activity and membrane-peptide interactions of fragments derived from the central helical hairpin of BAX, BCL-xL and BID. The results show a connection between the differing abilities of the assayed peptide fragments to contact, insert, destabilize and porate membranes and the activity of their cognate proteins in programmed cell death. CONCLUSION/SIGNIFICANCE: BCL-2 family-derived pore-forming helices thus represent structurally analogous, but functionally dissimilar membrane domains
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