51 research outputs found
A FENCING KINEMATIC ANALYSIS BASED ON COACHâS CRITERIA
The purpose of this study was to identify, based on coach's criteria, upper body and center of mass kinematic variables that lead to a good performance in epee fencing. We used an Optitrack motion capture system to evaluate one skilled amateur fencing athlete performing a lunge in the presence or not of a static opponent. In the presence of a static opponent (target), the individual developed a lower centre of mass forward velocity, a higher epeeâs tip forward velocity and improved synchronization between the upper and the lower limbs. The best-performed trials according to coach criteria showed differences in the elbow movement in both the armed and unarmed arm compared to the other trials. Our results highlights the importance of the unarmed arm to lunge performance and corroborate the idea that training with and without the use of a target improve different motor abilities
Quantitative-spatial assessment of soil contamination in S. Francisco de Assis due to mining activity of the Panasqueira mine (Portugal)
Through the years, mining and beneficiation processes produces large amounts of As-rich mine wastes laid up in huge tailings and open-air impoundments
(Barroca Grande and Rio tailings) that are the main source of pollution in the surrounding area once they are exposed to the weathering conditions leading to
the formation of AMD and consequently to the contamination of the surrounding environments, in particularly soils. In order to investigate the environmental
contamination impact on S. Francisco de Assis (village located between the two major impoundments and tailings) agricultural soils, a geochemical survey was
undertaken to assess toxic metals associations, related levels and their spatial distribution, and to identify the possible contamination sources. According to
the calculated contamination factor, As and Zn have a very high contamination factor giving rise to 65.4 % of samples with a moderate to high pollution
degree; 34.6 % have been classified as nil to very low pollution degree. The contamination factor spatial distribution put in evidence the fact that As, Cd, Cu,
Pb, and Zn soils contents, downstream Barroca Grande tailing, are increased when compared with the local Bk soils. The mechanical dispersion, due to
erosion, is the main contamination source. The chemical extraction demonstrates that the trace metals distribution and accumulation in S. Francisco de Assis
soils is related to sulfides, but also to amorphous or poorly crystalline iron oxide phases. The partitioning study allowed understanding the local chemical
elements mobility and precipitation processes, giving rise to the contamination dispersion model of the study area. The wind and hydrological factors are
responsible for the chemical elements transport mechanisms, the water being the main transporter medium and soils as one of the possible retention media
Collagen-based silver nanoparticles for biological applications: synthesis and characterization
Abstract\ud
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Background\ud
Type I collagen is an abundant natural polymer with several applications in medicine as matrix to regenerate tissues. Silver nanoparticles is an important nanotechnology material with many utilities in some areas such as medicine, biology and chemistry. The present study focused on the synthesis of silver nanoparticles (AgNPs) stabilized with type I collagen (AgNPcol) to build a nanomaterial with biological utility. Three formulations of AgNPcol were physicochemical characterized, antibacterial activity in vitro and cell viability assays were analyzed. AgNPcol was characterized by means of the following: ultravioletâvisible spectroscopy, dynamic light scattering analysis, Fourier transform infrared spectroscopy, atomic absorption analysis, transmission electron microscopy and of X-ray diffraction analysis.\ud
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Results\ud
All AgNPcol showed spherical and positive zeta potential. The AgNPcol at a molar ratio of 1:6 showed better characteristics, smaller hydrodynamic diameter (64.34â±â16.05) and polydispersity index (0.40â±â0.05), and higher absorbance and silver reduction efficiency (0.645 mM), when compared with the particles prepared in other mixing ratios. Furthermore, these particles showed antimicrobial activity against both Staphylococcus aureus and Escherichia coli and no toxicity to the cells at the examined concentrations.\ud
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Conclusions\ud
The resulted particles exhibited favorable characteristics, including the spherical shape, diameter between 64.34Â nm and 81.76Â nm, positive zeta potential, antibacterial activity, and non-toxicity to the tested cells (OSCC).FAPESP (14/02282-6)CAPES (AUX-PERM-705/2009)
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