543 research outputs found

    Drug Transport in Responding Lipid Membranes Can Be Regulated by an External Osmotic Gradient

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    In this paper, we demonstrate, for the first time, how an external osmotic gradient can be used to regulate diffusion of solutes across a lipid membrane. We present experimental and theoretical studies of the transport of different solutes across a monoolein membrane in the presence of an external osmotic gradient. The osmotic gradient introduces phase transformations in the membrane, and it causes nonlinear transport behavior. The external gradient can thus act as a kind of switch for diffusive transport in the skin and in controlled release drug formulations

    GyGSLA: A portable glove system for learning sign language alphabet

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    The communication between people with normal hearing with those having hearing or speech impairment is difficult. Learning a new alphabet is not always easy, especially when it is a sign language alphabet, which requires both hand skills and practice. This paper presents the GyGSLA system, standing as a completely portable setup created to help inexperienced people in the process of learning a new sign language alphabet. To achieve it, a computer/mobile game-interface and an hardware device, a wearable glove, were developed. When interacting with the computer or mobile device, using the wearable glove, the user is asked to represent alphabet letters and digits, by replicating the hand and fingers positions shown in a screen. The glove then sends the hand and fingers positions to the computer/mobile device using a wireless interface, which interprets the letter or digit that is being done by the user, and gives it a corresponding score. The system was tested with three completely inexperience sign language subjects, achieving a 76% average recognition ratio for the Portuguese sign language alphabet.info:eu-repo/semantics/publishedVersio

    Ageing perception in seniors’ formal caregivers

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    This paper explores the ageing perception of a group of seniors’ caregiver workers, particularly those who have direct contact with the elderly while performing their tasks. Therefore, we analyze the variables that influence this perception and the ones that can be good predictors. One hundred and forty-eight individuals took part in this study (a hundred and thirty- five females and twelve males) with ages between twentyone and sixty-five years old. It was applied the Portuguese versions of the tests Ageing Perception Questionnaire, the Self-Concept Scale (TSCS:2) and a sociodemographic questionnaire. The results showed that the ageing perception is more negative as age advances. On the other hand, individuals with higher education, training in the health field or with a stronger self-concept have a more positive ageing perception. The studied variables that best predict the emotional representation for ageing are the academic qualifications and the academic self-concept.info:eu-repo/semantics/publishedVersio

    Shape acquisition of rotating objects based on Laser Line Scanning

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    The present work proposes a methodology for 3D shape acquisition of objects through rotation-based Laser Line Scanning. This enables the acquisition of an object's 3D shape from multiple views, which leads to a more complete and accurate model

    Role of malnutrition and parasite infections in the spatial variation in children’s anaemia risk in Northern Angola

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    Anaemia has a significant impact on child development and mortality and is a severe public health problem in most countries in sub-Saharan Africa. Nutritional and infectious causes of anaemia are geographically variable and anaemia maps based on information on the major aetiologies of anaemia are important for identifying communities most in need and the relative contribution of major causes. We investigated the consistency between ecological and individual-level approaches to anaemia mapping, by building spatial anaemia models for children aged ≤15 years using different modeling approaches. We aimed to a) quantify the role of malnutrition, malaria, Schistosoma haematobium and soil-transmitted helminths (STH) for anaemia endemicity in children aged ≤15 years and b) develop a high resolution predictive risk map of anaemia for the municipality of Dande in Northern Angola. We used parasitological survey data on children aged ≤15 years to build Bayesian geostatistical models of malaria (PfPR≤15), S. haematobium, Ascaris lumbricoides and Trichuris trichiura and predict small-scale spatial variation in these infections. The predictions and their associated uncertainty were used as inputs for a model of anemia prevalence to predict small-scale spatial variation of anaemia. Stunting, PfPR≤15, and S. haematobium infections were significantly associated with anaemia risk. An estimated 12.5%, 15.6%, and 9.8%, of anaemia cases could be averted by treating malnutrition, malaria, S. haematobium, respectively. Spatial clusters of high risk of anaemia (>86%) were identified. Using an individual-level approach to anaemia mapping at a small spatial scale, we found that anaemia in children aged ≤15 years is highly heterogeneous and that malnutrition and parasitic infections are important contributors to the spatial variation in anemia risk. The results presented in this study can help inform the integration of the current provincial malaria control program with ancillary micronutrient supplementation and control of neglected tropical diseases, such as urogenital schistosomiasis and STH infection

    A novel control strategy based on predictive control for a bidirectional interleaved three-phase converter

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    An experimental confirmation of predictive control applied to a bidirectional interleaved three-phase (BIT) converter is presented. The BIT converter is a powerful solution for numerous applications, mainly, renewables interface, motor drivers, active rectifiers, and active power filters. However, a precise and robust digital control strategy is required, maintaining a low computational effort. In this paper, a predictive control based on continuous control set is proposed as a new control scheme for the BIT converter, permitting the control of the ac side current with fixed switching frequency and with a faster response. The predictive control scheme applied to the BIT converter is defined along the paper, evidencing in detail the digital employment aspects according to the discrete-time model of the BIT converter. An explicit experimental validation under realistic operating conditions is presented using a developed laboratorial prototype, highlighting the convenience of the control applied to the BIT converter.This work has been supported by FCT – Fundação para a Ciência e Tecnologia in the scope of the project: PEstUID/CEC/00319/2013. This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013. This work is financed by the ERDF – European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation < COMPETE 2020 Programme, and by National Funds through the Portuguese funding agency, FCT < Fundação para a Ciência e a Tecnologia, within project SAICTPAC/0004/2015< POCI< 01<0145<FEDER<016434. Mr. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by the Portuguese FCT agency.info:eu-repo/semantics/publishedVersio

    Translucent beads, shinier worlds: a preliminary approach to fluorite beads from the Iberian Peninsula

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    Prehistoric ornaments are considered as aesthetic categories that show, emphasize and materialize codes, metaphors and narratives socially shared (Bar-Yosef Mayer and Porat 2008; DeMarrais et al. 1996; Hodder 1982; Tilley 1999; Wright and Garrard, 2003). Some values and properties as colour (Jones and MacGregor, 2002; Sahlins, 1976), but also brightness (Gaydarska y Chapman, 2008), have been highlighted as determinant of cultural/symbolic and technological choices in Prehistoric materiality, conditionating the raw material selection. Transparent and translucent minerals are considered for the Neolithic onwards as rare and highly symbolic elements. This paper shows that translucent beads accounts for an ample variety of raw material (i.e., calcite, muscovite, quartz varieties…). Fluorite (CaF2) occurs worldwide, and it´s relatively frequent in western Europe, and the Iberian Peninsula. Its properties (4 hardness in Mohs´ Scale) made it easy to worked out and cleavage for making ornaments. Some Belgium´s Upper Palaeolithic sites gave important evidences of its use (Goemaere et al., 2013; Jungels and Goemaere, 2007) and French and Belgian Neolithic and Copper Age communities used fluorite as a rare raw material for personal ornaments.N/

    Detection of Escherichia coli O157 by Peptide Nucleic Acid Fluorescence In Situ Hybridization (PNA-FISH) and Comparison to a Standard Culture Method

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    Despite the emergence of non-O157 shiga toxin-producing Escherichia coli (STEC) infections, E. coli O157 serotype is still the most commonly identified STEC in world. It causes high morbidity and mortality, and has been responsible for a number of outbreaks in many parts of the world. Various methods have been developed to detect this particular serotype, but standard bacteriological methods remain as the gold standard.In here, we propose a new peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) method for the rapid detection of E. coli O157.Testing on 54 representative strains showed that the PNA probe is highly sensitive and specific to E. coli O157. Then, the method was optimized for the detection in food samples. Ground beef and unpasteurized milk samples were artificially contaminated with E. coli O157 concentrations ranging from 1×10-2 to 1×102 CFU per 25g or ml of food. Samples were then pre-enriched and analyzed by both the traditional bacteriological method (ISO 16654:2001) and PNA-FISH. The PNA-FISH method performed well in both types of food matrixes with a detection limit of 1 CFU/25 g or ml of food samples. Tests on 60 food samples have shown a specificity value of 100% (95% CI 82.83 - 100), a sensitivity of 97.22% (95% CI, 83.79 - 99.85) and an accuracy of 98,33% (CI 95%, 83.41 - 99.91). Results indicate that PNA-FISH performed as well as the traditional culture methods and can reduce the diagnosis time to 1 day.This work was supported by the Portuguese Institute Fundacao para a Ciencia e Tecnologia (FCT), project PIC/IC/82815/2007. C.A. acknowledges FCT for individual postdoctoral fellowship SFRH/BPD/74480/2010. We also acknowledge Biomode S.A. for providing some supplies for this project

    Benzo[a]phenoxazinium chlorides functionalized with chloride atoms and/or ester groups

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    Proceedings of the 19th Int. Electron. Conf. Synth. Org. Chem.With the aim of contributing to the development of fluorescent near-infrared (NIR) probes with applications in biomedicine, our research group is committed to the development of new water-soluble benzo[a]phenoxazine derivatives and the evaluation of their photophysical and biological potential. Herein we report the photophysical behaviour in anhydrous ethanol of four synthesised benzo[a]phenoxazinium chlorides, possessing the (3-chloropropyl)amino and/or (4-ethoxy-4- oxobutyl)amino groups at 5- and 9-positions of the polycyclic system.Thanks are due to the Fundação para a Ciência e Tecnologia (FCT, Portugal) for financial support to the NMR portuguese network (PTNMR, Bruker Avance III 400-Univ. Minho), FCT and FEDER (European Fund for Regional Development)-COMPETE-QREN-EU for financial support to the Research Centres CFUM [PEst-C/FIS/UI0607/2011 (F-COMP-01-0124-FEDER-022711)] and CQ/UM [PEstC/QUI/UI0686/2013(FCOMP-01-0124-FEDER-022716)]. A post-doctoral grant to B. R. Raju (SFRH/BPD/62881/2009) is also acknowledged to FCT, POPH-QREN, FSE.info:eu-repo/semantics/publishedVersio

    Sliding mode control of an innovative single-switch three-level active rectifier

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    This paper presents the sliding mode control (SMC) applied to an innovative active rectifier. This proposed active rectifier is constituted by a single-switch, and operates with three voltage levels, evidencing a set of advantages when compared with conventional approaches of power factor correction topologies. Taking into account the diversity of applications for this type of power converter, the SMC is used in order to obtain a robust current tracking. Since the active rectifier is controlled according to the ac grid-side current, the error between such current and its reference is determined, and by employing the SMC, this error is minimized during each sampling period with the objective of selecting the state of the single-switch. A comprehensive description about the SMC implementation, supported by the overall operation of the active rectifier, is presented throughout the paper. The obtained computational results for a set of different operating conditions, comprising significant power ranges and sudden variations, confirm the accurate application of the SMC when applied to the proposed single-switch three-level active rectifier. A comparison is also established with other current control, allowing to confirm the precise application of the SMC strategy.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019. This work has been supported by FCT Project newERA4GRIDs PTDC/EEI-EEE/30283/2017, and by the FCT Project DAIPESEV PTDC/EEI-EEE/30382/2017. Tiago Sousa is supported by the doctoral scholarship SFRH/BD/134353/2017 granted by FCT
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