129 research outputs found

    Bivariate Empirical Mode Decomposition

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    IN VIVO STIFFNESS EVALUATION OF HUMAN TENDONS

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    The behaviour of tendons was largely studied in vitro conditions, both in human and animal tissues (Abrahams, 1967; Benedict et a/., 1968; Woo et al. 1981), but information available in the literature about human tendons in vivo is scarce. Meanwhile, an advance in real-time ultrasonography enables the non-invasive determination of the displacement of the fascicles during muscle contraction, which made possible the study of deformation of the aponeurosis and the tendon (Fukashiro et al. 1995). Such techniques were used in the past for the study of vertical jumps. For instance, Kubo et al. (1999) showed that tendons have a parabolic like force-length relationship at low stress, and an almost linear relation at higher loads. To our knowledge, however, it was never used for the analysis of long jumpers

    BIOMECHANICAL ANALYSIS OF ELEMENTARY BALLET JUMPS: INTEGRATION OF FORCE PLATE DATA AND EMG RECORDS

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    The purpose of this research was to analyze the electromyographic (EMG) activity, ground reaction force and muscular behavior (concentric,isometric or eccentric) of the lower limb during elementary ballet jumps: "saute" in first position; "saute" in fifth position; "saute en cou de pie". Three trials of each jump were performed by a experienced female Ballet dancer. Results pointed out the existence of a pre-activation effect before landing in almost all cases. They also showed the negative correlation of EMG on the agonistantagonist pair tibialis anterior and medial gastrocnemius and a positive correlation of the EMG activity of adductors and rectus femoris, between medial gastrocnemius and soleus, and between rectus femoris and the vertical ground reaction force. However, most of the parameters measured show great sensitivity to the technical execution making it impossible to generalize these findings

    Acetylcholine release and choline uptake by cuttlefish (Sepia officinalis) optic lobe synaptosomes

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    Acetylcholine (ACh), which is synthesized from choline (Ch), is believed to hold a central place in signaling mechanisms within the central nervous system (CNS) of cuttlefish (Sepia officinalis) and other coleoid cephalopods. Although the main elements required for cholinergic function have been identified in cephalopods, the transmembrane translocation events promoting the release of ACh and the uptake of Ch remain largely unsolved. The ACh release and Ch uptake were quantitatively studied through the use of in vitro chemiluminescence and isotopic methods on a subcellular fraction enriched in synaptic nerve endings (synaptosomes) isolated from cuttlefish optic lobe. The ACh release evoked by K+ depolarization was found to be very high (0.04 pmol ACh.s-(1).mg(-1) protein). In response to stimulation by veratridine, a secretagogue (a substance that induces secretion) that targets voltage-gated Na+ channels, the release rate and the total amount of ACh released were significantly lower, by 10-fold, than the response induced by KCl. The high-affinity uptake of choline was also very high (31 pmol Ch.min(-1).mg(-1) protein). The observed ACh release and Ch uptake patterns are in good agreement with published data on preparations characterized by high levels of ACh metabolism, adding further evidence that ACh acts as a neurotransmitter in cuttlefish optic lobe.FCTPOCTI/BSE/46721/2002SFRH/BPD/14677/2003SFRH/BD/1079/2000SFRH/BD/6403/2001SFRH/BD/18101/2004EC (to Y.D.) - LIPIDIET - QLK1-CT-2002-0017

    Low-cost/high-precision smart power supply for data loggers

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    This paper presents a low-cost/high-precision smart power supply for application on data loggers. The microprocessor unit is the brain of the system and manages the events and was optimized to provide electrical energy to the electronic devices under normal operation and under the presence of disruptive events. The measurements showed that when switching either from battery to AC or from AC to battery, neither caused the shutdown of the power supply nor affected the behavior of the power supply. The power supply was able to charge 80% of the battery on a fast recharge of 1 h and the remaining 20% on a slow recharge of 2 h. The current allocated to the battery did not affect the operation of the power supply. The tests also showed that the power supply was able to transmit relevant information about its operation to external computers through a serial connection. This information includes the voltages at the battery and at the output of the voltage regulators, the voltage level of the AC network, the level of the battery charge and if it was being recharged, the current being drained, the internal temperatures at two locations (one measured on the resistor that limits battery charge and another measured on the output diode of the regulators), and whether the cooling system is being used. The total cost of this smart power supply is less than $150, demonstrating good potential for its popularization.This work was partially supported by FCT national funds, under the national support to R&D units grant, through the reference project UIDB/04436/2020 and UIDP/04436/2020. This research was also partially supported by the FAPESP agency (Fundação de Amparo à Pesquisa do Estado de São Paulo) through the project with the reference 2019/05248-7. Professor João Paulo Carmo was support by a PQ scholarship with the reference CNPq 304312/2020-7

    Genetic variants of ABC and SLC transporter genes and chronic myeloid leukaemia: impact on susceptibility and prognosis

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    Solute carrier (SLC) and ATP-binding cassette (ABC) transporters comprise a variety of proteins expressed on cell membranes responsible for intrusion or extrusion of substrates, respectively, including nutrients, xenobiotics, and chemotherapeutic agents. These transporters mediate the cellular disposition of tyrosine kinase inhibitors (TKIs), and their genetic variants could affect its function, potentially predisposing patients to chronic myeloid leukaemia (CML) and modulating treatment response. We explored the impact of genetic variability (single nucleotide variants—SNVs) of drug transporter genes (ABCB1, ABCG2, SLC22A1, and SLC22A5) on CML susceptibility, drug response, and BCR-ABL1 mutation status. We genotyped 10 SNVs by tetra-primers-AMRS-PCR in 198 CML patients and 404 controls, and assessed their role in CML susceptibility and prognosis. We identified five SNVs associated with CML predisposition, with some variants increasing disease risk, including TT genotype ABCB1 (rs1045642), and others showing a protective effect (GG genotype SLC22A5 rs274558). We also observed different haplotypes and genotypic profiles associated with CML predisposition. Relating to drug response impact, we found that CML patients with the CC genotype (rs2231142 ABCG2) had an increased risk of TKI resistance (six-fold). Additionally, CML patients carrying the CG genotype (rs683369 SLC22A1) presented a 4.54-fold higher risk of BCR-ABL1 mutations. Our results suggest that drug transporters’ SNVs might be involved in CML susceptibility and TKI response, and predict the risk of BCR-ABL1 mutations, highlighting the impact that SNVs could have in therapeutic selection.info:eu-repo/semantics/publishedVersio

    Muon Array with RPCs for Tagging Air showers (MARTA)

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    We discuss the concept of an array with Resistive Plate Chambers (RPC) for muon detection in ultra-high energy cosmic ray (UHECR) experiments. RPC have been used in particle physics experiments due to their fast timing properties and spatial resolution. The operation of a ground array detector poses challenging demands, as the RPC must operate remotely under extreme en- vironments, with limited power and minimal maintenance. In its baseline configuration, each MARTA unit includes one 1.5x1.2 m 2 RPC, with 64 pickup electrodes (pads). The DAQ sys- tem is based on an ASIC, allowing one to read out the high number of channels with low power consumption. Data are recorded using a dual technique: single particle counting with a simple threshold on the signal from each pad and charge integration for high occupancy. The RPC, DAQ, High Voltage and monitoring systems are enclosed in an aluminum-sealed case, providing a com- pact and robust unit suited for outdoor environments, which can be easily deployed and connected. The RPCs developed at LIP-Coimbra are able to operate using very low gas flux, which allows running them for few years with a small gas reservoir. Several full-scale units are already installed and taking data in several locations and with different configurations, proving the viability of the MARTA concept. By shielding the detector units with enough slant mass to absorb the electro- magnetic component in the air showers, a clean measurement of the muon content is allowed, a concept to be implemented in a next generation of UHECR experiments. The specificities of a MARTA unit are presented, which include particle counting with high efficiency, time resolu- tion and spatial segmentation. The potential of the MARTA concept for muon measurements in air showers is assessed, as well as tentative methods for calibration and cross-calibrations with existing detectors.Peer Reviewe

    Defining positioning in a core ontology for robotics

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    Unambiguous definition of spatial position and orientation has crucial importance for robotics. In this paper we propose an ontology about positioning. It is part of a more extensive core ontology being developed by the IEEE RAS Working Group on ontologies for robotics and automation. The core ontology should provide a common ground for further ontology development in the field. We give a brief overview of concepts in the core ontology and then describe an integrated approach for representing quantitative and qualitative position information.3-7 November 201

    Sialic Acid Glycobiology Unveils Trypanosoma cruzi Trypomastigote Membrane Physiology.

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    Trypanosoma cruzi, the flagellate protozoan agent of Chagas disease or American trypanosomiasis, is unable to synthesize sialic acids de novo. Mucins and trans-sialidase (TS) are substrate and enzyme, respectively, of the glycobiological system that scavenges sialic acid from the host in a crucial interplay for T. cruzi life cycle. The acquisition of the sialyl residue allows the parasite to avoid lysis by serum factors and to interact with the host cell. A major drawback to studying the sialylation kinetics and turnover of the trypomastigote glycoconjugates is the difficulty to identify and follow the recently acquired sialyl residues. To tackle this issue, we followed an unnatural sugar approach as bioorthogonal chemical reporters, where the use of azidosialyl residues allowed identifying the acquired sugar. Advanced microscopy techniques, together with biochemical methods, were used to study the trypomastigote membrane from its glycobiological perspective. Main sialyl acceptors were identified as mucins by biochemical procedures and protein markers. Together with determining their shedding and turnover rates, we also report that several membrane proteins, including TS and its substrates, both glycosylphosphatidylinositol-anchored proteins, are separately distributed on parasite surface and contained in different and highly stable membrane microdomains. Notably, labeling for α(1,3)Galactosyl residues only partially colocalize with sialylated mucins, indicating that two species of glycosylated mucins do exist, which are segregated at the parasite surface. Moreover, sialylated mucins were included in lipid-raft-domains, whereas TS molecules are not. The location of the surface-anchored TS resulted too far off as to be capable to sialylate mucins, a role played by the shed TS instead. Phosphatidylinositol-phospholipase-C activity is actually not present in trypomastigotes. Therefore, shedding of TS occurs via microvesicles instead of as a fully soluble form
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