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Alves M.M.,Piaget Institute
Clinical hemorheology and microcirculation | Year: 2013

The aim of this work was to investigate the rheological behaviour of human blood, in a controlled stress rheometer, using different cone-plate and parallel plate geometries. Steady-shear (flow curves and kinetics) and oscillatory (strain, frequency and time sweeps) tests were performed at 37°C. The results demonstrated that rheological data are significantly influenced by the measuring geometry and the rheological parameters obtained from rheological models must be analysed with great caution. The Cross model provided a better fit of the flow curves and the Power Law model gave a better concordance between the rheological parameters obtained with the different measuring systems. The oscillatory measurements demonstrated a linear viscoelastic behaviour below a critical frequency and the Friedrich-Braun model described well the frequency sweeps experimental data in that region. The correlation between steady-shear and oscillatory properties (Cox-Merz rule) suggests that the two methods can be complementary and may give important information on red blood cells aggregation and deformability. Results from oscillatory time sweeps confirm a blood aggregation process in two steps.


Martins R.B.,Piaget Institute | Martins R.B.,Piaget Alimentar Unipessoal Lda | Hogg T.,Catholic University of Portugal | Otero J.G.,University of Santiago de Compostela
Food Control | Year: 2012

The aim of this study was to assess the food hygiene knowledge of professional food handlers from an institutional catering company which manufactures and distributes meals to the canteens of schools, kindergartens and nursing homes in Portugal. A total of 101 food handlers from 18 geographically distributed business units were assessed. Data collection employed a previously used, multiple-choice questionnaire, aimed at exploring the food safety knowledge and practices of individual respondents. The average score of questions answered correctly was 13 out of 23 (56.5%) with a standard deviation (SD) of 3.22. However, the percentage of correct answers varies with the issues questioned, being significantly lower on issues such as temperature control (p < 0.001) and sources of contamination/high-risk foods (p < 0.001). The level of knowledge was influenced by the level of formal education (p = 0.025) of respondents. The results reinforce the importance of conducting a preliminary assessment of training needs and evaluating the effectiveness of training. © 2011 Elsevier Ltd.


Rocha-Santos T.A.P.,University of Aveiro | Rocha-Santos T.A.P.,Piaget Institute
TrAC - Trends in Analytical Chemistry | Year: 2014

Magnetic nanoparticles (MNPs) have attracted a growing interest in the development and fabrication of sensors and biosensors for several applications. MNPs can be integrated into the transducer materials and/or be dispersed in the sample followed by their attraction by an external magnetic field onto the active detection surface of the (bio)sensor. This review describes and discusses the recent applications of MNPs in sensors and biosensors, taking into consideration their analytical figures of merit. This work also addresses the future trends and perspectives of sensors and biosensors based on MNPs. © 2014 Elsevier B.V.


Chagas D.,Piaget Institute
Occupational Safety and Hygiene III - Selected Extended and Revised Contributions from the International Symposium on Safety and Hygiene | Year: 2015

The aim of this research is to identify the association between Work-related MusculoskeletalDisorders with the home carers activity in providing care for the elderly arising from the risks to whichthey are exposed. For the development of this study a questionnaire was addressed to 90 workers fromthe domiciliary care services. It was found according to the studied dimensions that upper limbs, dorsaland lumbar areas prevailed, allowing to confirm that the direct action helpers have a high risk of acquiringWork-related Musculoskeletal Disorders (WRMSDs), considering that these are preponderant to thetasks performed such as: using excessive strength, inadequate postures and the repetition of movements. © 2015 Taylor & Francis Group, London.


Rocha-Santos T.,University of Aveiro | Rocha-Santos T.,Piaget Institute | Duarte A.C.,University of Aveiro
TrAC - Trends in Analytical Chemistry | Year: 2015

Plastics can be found in food packaging, shopping bags, and household items, such as toothbrushes and pens, and facial cleansers. Due to the high disposability and low recovery of discharged materials, plastics materials have become debris accumulating in the environment. Microplastics have a dimension <5 mm and possess physico-chemical properties (e.g., size, density, color and chemical composition) that are key contributors to their bioavailability to organisms. This review addresses the analytical approaches to characterization and quantification of microplastics in the environment and discusses recent studies on their occurrence, fate, and behavior. This critical overview includes a general assessment of sampling and sample handling, and compares methods for morphological and physical classification, and methodologies for chemical characterization and quantification of the microplastics. Finally, this review addresses the advantages and the disadvantages of these techniques, and comments on future applications and potential research interest within this field. © 2014 Elsevier B.V.


Justino C.I.L.,University of Aveiro | Rocha-Santos T.A.,University of Aveiro | Duarte A.C.,University of Aveiro | Rocha-Santos T.A.,Piaget Institute
TrAC - Trends in Analytical Chemistry | Year: 2010

Although the development of clinical sensors and biosensors has increased in recent years, improvements in sensitivity, selectivity, limits of detection, fast response and miniaturization are yet to be attained. Health care appears to provide the best opportunity for sensor development. Among the wide range of different sensors and biosensors, electrochemical biosensors are the most common in the clinical field, due to their high sensitivity and selectivity, portability, rapid response time and low cost. This article provides an up-to-date overview of the analytical performance of sensors and biosensors in clinical applications by discussing recent improvements, particularly due to the impact of nanotechnology. © 2010 Elsevier Ltd.


Justino C.I.L.,University of Aveiro | Rocha-Santos T.A.P.,University of Aveiro | Cardoso S.,University of Aveiro | Duarte A.C.,University of Aveiro | And 2 more authors.
TrAC - Trends in Analytical Chemistry | Year: 2013

We provide a state-of-the-art review of the main strategies for the enhancement of analytical performance of sensors using nanomaterials, particularly nanowires and carbon-based materials. We emphasize the way to overcome the problem of device-to-device variation. We discuss the study of the influence of nanomaterial characteristics, sensor dimensions and operational conditions on sensing performance, and the application of appropriate calibration models. © 2013 Elsevier Ltd.


Justino C.I.L.,University of Aveiro | Rocha-Santos T.A.P.,University of Aveiro | Rocha-Santos T.A.P.,Piaget Institute | Duarte A.C.,University of Aveiro
TrAC - Trends in Analytical Chemistry | Year: 2013

Healthcare is the combination of diagnosis, treatment, and prevention of any disease in humans, which is being constantly improved with efficient, rapid, useful point-of-care (POC) technologies as molecular diagnostic devices. In this way, biosensors based on carbon nanotubes (CNTs) have been developed and used in recent years, due to their high sensitivity, specificity, rapidity in analysis, low cost, and ease of use. This review provides an up-to-date overview of the analytical performance of emerging technologies in the form of POC biosensors based on CNTs, which can be implemented in the clinical area, mainly for the detection of cancer biomarkers and glucose (analytes associated with two of the most common diseases in developed world, cancer and diabetes).This review also addresses the synthesis, the properties and the areas of application of CNTs and the characteristics and the clinical importance of POC testing. © 2013 Elsevier Ltd.


Justino C.I.L.,University of Aveiro | Rocha-Santos T.A.,University of Aveiro | Rocha-Santos T.A.,Piaget Institute | Duarte A.C.,University of Aveiro
TrAC - Trends in Analytical Chemistry | Year: 2011

Efficient sampling and characterization of nanoparticles have been challenging tasks in environmental research due to the limitations of regular analytical techniques (e.g., dynamic light scattering, and nuclear magnetic resonance and UV-Vis spectroscopies) - especially the difficulties in their application to in situ and real-time monitoring, which are intrinsically related to the nanometer-size range.This critical overview aims at characterizing recent instrumental techniques (e.g., hygroscopic tandem-differential mobility analysis, thermal desorption-gas chromatography-mass spectrometry, and time-of-flight secondary ion mass spectrometry) for sampling and characterization of individual nanoaerosols in terms of their general operation principles, analytical parameters, advantages and limitations. We also discuss classification of this instrumentation based on off-line and/or in situ methods, and on physical and chemical characterization of nanoaerosols. Further, we summarize recent air-quality studies aimed at understanding the physical and chemical behavior of aerosols in different environments. © 2011 Elsevier Ltd.


Correia P.R.,Polytechnic Institute of Viseu | Nunes M.C.,Piaget Institute | Nunes M.C.,University of Lisbon | Beirao-da-Costa M.L.,University of Lisbon
Food Hydrocolloids | Year: 2012

The functionality of starch from chestnut (Castanea sativa Mill.) fruits isolated by alkaline and enzymatic methods were assessed. The studied properties included: solubility, swelling power, pasting properties, synaeresis, turbidity, and thermal and rheological behaviours. In addition amylose and resistant starch content were also evaluated. Results showed that the starch isolation method induced changes in most of those properties. Extracted starches (with high contents of amylose and resistant starch) showed low and similar swelling solubility values for all of the samples. Gelatinisation temperatures were also similar (61.5-63.0°C), but the enzymatic method induced lower consistencies at 95°C and after holding at this temperature. High values of setback were found, which were clearly affected by the isolation method. This parameter presented lower values for starches isolated by alkaline method (160 BU and 235 BU, respectively for Martainha and Longal). Starches did not present a peak consistency during pasting. Turbidity and synaeresis values were low at room temperature. Synaeresis increased when pastes were stored at low temperatures. This effect was more evident for the material isolated by enzymatic method. All of the isolation starches presented low enthalpy values (3.0-3.5. J/g), but the activation energy was higher for Martainha starches and for starches isolated by A3S method. Pastes showed viscoelastic behaviour, with a predominance of elastic property, forming strong gels after cooling. Longal variety seems to be less resistant to the effect of isolation method. In general starches isolated by the alkali method present the best functional properties as a food ingredient. © 2011 Elsevier Ltd.

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