1,492 research outputs found

    A Comparative Evaluation of Heart Rate Estimation Methods using Face Videos

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    This paper presents a comparative evaluation of methods for remote heart rate estimation using face videos, i.e., given a video sequence of the face as input, methods to process it to obtain a robust estimation of the subjects heart rate at each moment. Four alternatives from the literature are tested, three based in hand crafted approaches and one based on deep learning. The methods are compared using RGB videos from the COHFACE database. Experiments show that the learning-based method achieves much better accuracy than the hand crafted ones. The low error rate achieved by the learning based model makes possible its application in real scenarios, e.g. in medical or sports environments.Comment: Accepted in "IEEE International Workshop on Medical Computing (MediComp) 2020

    Improving Peruvian Manufacture of Welding Electrodes

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    Ceramic identity contributes to mechanical properties and osteoblast behavior on macroporous composite scaffolds.

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    Implants formed of metals, bioceramics, or polymers may provide an alternative to autografts for treating large bone defects. However, limitations to each material motivate the examination of composites to capitalize on the beneficial aspects of individual components and to address the need for conferring bioactive behavior to the polymer matrix. We hypothesized that the inclusion of different bioceramics in a ceramic-polymer composite would alter the physical properties of the implant and the cellular osteogenic response. To test this, composite scaffolds formed from poly(lactide-co-glycolide) (PLG) and either hydroxyapatite (HA), β-tricalcium phosphate (TCP), or bioactive glass (Bioglass 45S®, BG) were fabricated, and the physical properties of each scaffold were examined. We quantified cell proliferation by DNA content, osteogenic response of human osteoblasts (NHOsts) to composite scaffolds by alkaline phosphatase (ALP) activity, and changes in gene expression by qPCR. Compared to BG-PLG scaffolds, HA-PLG and TCP-PLG composite scaffolds possessed greater compressive moduli. NHOsts on BG-PLG substrates exhibited higher ALP activity than those on control, HA-, or TCP-PLG scaffolds after 21 days, and cells on composites exhibited a 3-fold increase in ALP activity between 7 and 21 days versus a minimal increase on control scaffolds. Compared to cells on PLG controls, RUNX2 expression in NHOsts on composite scaffolds was lower at both 7 and 21 days, while expression of genes encoding for bone matrix proteins (COL1A1 and SPARC) was higher on BG-PLG scaffolds at both time points. These data demonstrate the importance of selecting a ceramic when fabricating composites applied for bone healing

    Mechanical thrombectomy with a novel device: initial clinical experience with the ANA thrombectomy device

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    Mechanical thrombectomy; New device; StrokeTrombectomia mecànica; Nou dispositiu; IctusTrombectomía mecánica; Nuevo dispositivo; IctusIntroduction The ANA™ (Anaconda Biomed) thrombectomy system is a novel stroke thrombectomy device comprising a self-expanding funnel designed to reduce clot fragmentation by locally restricting flow while becoming as wide as the lodging artery. Once deployed, ANA allows distal aspiration in combination with a stentretriever (SR) to mobilize the clot into the funnel where it remains copped during extraction. We investigate safety and efficacy of ANA™ in a first-in-man study. Methods Prospective data was collected on 35 consecutive patients treated as first line with ANA™ at a single centre. Outcome measures included per-pass reperfusion scores, symptomatic intracerebral hemorrhage (sICH), NIHSS at day 5, and mRS at 90 days. Results Median NIHSS was 12(9−18). Sites of primary occlusion were: 5 ICA, 15 M1-MCA, 15 M2-MCA. Primary performance endpoint, mTICI 2b-3 within 3 passes without rescue therapy was achieved in 91.4% (n = 32) of patients; rate of complete recanalization (mTICI 2c-3) was 65.7%. First pass complete recanalization rate was 42.9%, and median number of ANA passes 1(IQR: 1−2). In 17.1% (n = 6) rescue treatment was used; median number of rescue passes was 2(1–7), leading to a final mTICI2b-3rate of 94.3% (n = 33). There were no device related serious adverse events, and rate of sICH was 5.7% (n = 2). At 5 days median NIHSS was 1 (IQR 1−6) and 90 days mRS 0−2 was achieved in 60% of patients. Conclusions In this initial clinical experience, the ANA™ device achieved a high rate of complete recanalization with a good safety profile and favourable 90 days clinical outcomes.The study was funded by Anaconda Biomed S.L

    Modeling and control design of a Vienna rectifier based electrolyzer

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    Hydrogen production is an interesting alternative of storing energy. Electrolyzers produce hydrogen through water electrolysis; the resulting hydrogen is later used to generate electricity by using fuel cells, that reverse the process. Electrolyzers use rectifiers to convert the grid ac voltage into dc voltage for supplying the electrolyzer cells. Previous research used a rectification process based on conventional rectifiers (diode-or thyristor-based) which draw non-sinusoidal current from the main grid. This requires increased filtering to prevent power quality problems and equipment malfunctioning/failure. In addition, previous literature assumed simplified models for the power electronics converters and lacked a detailed control system. The Vienna rectifier is a non-regenerative converter that produces sinusoidal currents with low losses due to the reduced number of active switches. This manuscript proposes using the Vienna rectifier as an interface to connect electrolyzers to the ac grid. The dc voltage applied to the electrolyzer is regulated by using another DC-DC converter, which is selected to be a synchronous buck converter for simplicity and maximum efficiency. In this paper, the models of the Vienna rectifier, synchronous buck converter, and the electrolyzer are developed along with their respective controls. The control system has the ability to function in two operation modes for the overall reference: hydrogen production and power demand. The first one is adequate for grid-connected operation and the later for off-grid operation. Simulation results are given to show the validity of the proposed procedures

    1,4-Cyclohexanedicarboxylato-bridged cobalt coordination polymers: Synthesis, crystal structures and magnetic properties

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    1,4-Cyclohexanedicarboxylato-bridged cobalt coordination polymers: Synthesis, crystal structures and magnetic propertiesThree coordination polymers have been synthesized, using self-assembly solution reactions at ambient conditions, combining Co(II) ion with 1,4-ciclohexanedicarboxylic acid, in the presence of 1,10-phenantrolione and two different 2,20-bipyridines, as co-ligands: [Co(H2O)(cdc)(phen)]n (1); {[Co(H2O)(cdc)(4dmb)] 2H2O}n (2); {[Co(H2O)(cdc)(5dmb)] 3H2O}n (3), where cdc = e,a-cis-1,4-ciclohexanedicarboxylato, phen = 1,10-phenantroline, 4dmb = 4,40-dimethyl-2,20-bipyridine, and 5dmb = 5,50-dimethyl-2,20-bipyridine. Crystallographic studies show that these compounds have one-dimensional (1D) structures; Co(II) in 1–3 is six-coordinated with a distorted-octahedral coordination sphere. Complexes 2 and 3 exhibit a novel bridging motif of the cdc ligand in its equatorial, axial cis configuration. In addition, the solid-state self-assembly of the polymeric structure of 1 gives rise to a 2D supramolecular framework, mainly through hydrogen bonding. In contrast, complex 2 forms an infinite 1D supramolecular array, made of double Co ion rows bridged by hydrogen bonding interactions. Complex 3 generates an intricate 2D supramolecular framework also throughout hydrogen bonding. The thermal stabilities of the three coordination polymers were investigated. Magnetic properties measurements reveal that complexes 1–3 exhibit weak antiferromagnetic ordering with h(C-W) = 9.6, 5.8 and 7.5 K, and E2 = 0.51, 0.16 and 0.28 cm 1, accordingly to Curie-Weiss model and Rueff phenomenological approach, respectively

    Analytical methodologies based on LC–MS/MS for monitoring selected emerging compounds in liquid and solid phases of the sewage sludge

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    In this work, two analytical methodologies based on liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) were developed for quantification of emerging pollutants identified in sewage sludge after a previous wide-scope screening. The target list included 13 emerging contaminants (EC): thiabendazole, acesulfame, fenofibric acid, valsartan, irbesartan, salicylic acid, diclofenac, carbamazepine, 4-aminoantipyrine (4- AA), 4-acetyl aminoantipyrine (4-AAA), 4-formyl aminoantipyrine (4-FAA), venlafaxine and benzoylecgonine. The aqueous and solid phases of the sewage sludge were analyzed making use of Solid-Phase Extraction (SPE) and UltraSonic Extraction (USE) for sample treatment, respectively. The methods were validated at three concentration levels: 0.2, 2 and 20mg L 1 for the aqueous phase, and 50, 500 and 2000mg kg 1 for the solid phase of the sludge. In general, the method was satisfactorily validated, showing good recoveries (70–120%) and precision (RSD < 20%). Regarding the limit of quantification (LOQ), it was below 0.1mg L 1 in the aqueous phase and below 50mg kg 1 in the solid phase for the majority of the analytes. The method applicability was tested by analysis of samples from a wider study on degradation of emerging pollutants in sewage sludge under anaerobic digestion. The key benefits of these methodologies are: SPE and USE are appropriate sample procedures to extract selected emerging contaminants from the aqueous phase of the sewage sludge and the solid residue. LC–MS/MS is highly suitable for determining emerging contaminants in both sludge phases. Up to our knowledge, the main metabolites of dipyrone had not been studied before in sewage sludge. ãFinancial support of Generalitat Valenciana (Prometeo II/2014/023,ISIC/2014/016

    Behaviour of emerging contaminants in sewage sludge after anaerobic digestion

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    Nowadays, there is an increasing concern over the presence of contaminants in the aquatic environment, where they can be introduced from wastewater after their incomplete removal in the treatment plants. In this work, degradation of selected emerging pollutants in the aqueous and solid phases of sewage sludge has been investigated after anaerobic digestion using two different digesters: mesophilic and thermophilic. Initially, sludge samples were screened by ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS) for identification of emerging contaminants in the samples. In a second step, a target quantitative method based on LC coupled to tandem MS was applied for selected pollutants identified in the previous screening. The behaviour of the compounds under anaerobic conditions was studied estimating the degradation efficiency and distribution of compounds between both sludge phases. Irbesartan and benzoylecgonine seemed to be notably degraded in both phases of the sludge. Venlafaxine showed a significant concentration decrease in the aqueous phase in parallel to an increase in the solid phase. The majority of the compounds showed an increase of their concentrations in both phases after the digestion. Concentrations in the solid phase were commonly higher than in the aqueous for most contaminants, indicating that they were preferentially adsorbed onto the solid particles.The authors are very grateful to the Ecophysiology and Biotechnology group (University Jaume I) and to The Institute of Aquaculture “Torre de la Sal” (IATS) (Consejo Superior de Investigaciones Científicas, CSIC) for using their lyophilizer systems. The financial support of Generalitat Valenciana (Prometeo II/2014/023, ISIC/2014/016) is also acknowledged
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