1,475 research outputs found

    Low-intensity resistance exercise training increases lower limb force in healthy retirees

    Get PDF
    INTRODUCTION: Aging is associated with decreasing muscle strength. Older people who have never done resistance work in a gym require gradual training programs to help them increasing confidence on this type of training. The use of low intensity resistance exercise with slow movements and tonic force improvement has been proposed as an effective method to increase muscular strength. There is little literature on the effect of intensity training on 30% of one repetition maximum (RM). PURPOSE: To establish the changes in the strength of upper and lower limb force after participating in a 10 week low-intensity resistance exercise for a group of healthy retirees aged between 50 and 70 years. METHODS: Quasi-experimental design, with two measurements. Fifty-eight participants were separated into two groups according to their available schedule. The experimental group received low-intensity resistance training for ten weeks, three times a week, with an intensity of 30 to 60% RM. The control group received no training. Physical tests applied to both groups were: handgrip strength with digital dynamometer, Short Physical Performance Battery (SPPB) and 8-Foot up and go test (FUGT).RESULTS: Forty nine participants completed the study (total dropout rate was 16%) from which 57% were women. Participants in the experimental group (n = 31) had improvements in SPPB and FUGT tests (p \u3c.05). Without changes in handgrip strength. On the other hand, any changes were observed in the control group. CONCLUSION: The results indicate that a low-intensity resistance training (30% 1RM) is a useful method to increase muscle strength of lower limbs in healthy older adults. Due to the interference effect of training, more time is required to observe changes in the dynamic strength of the upper limbs. This type of training program is useful for promoting functionality in older adults reluctant to resistance training

    Effect of the Reduction Temperature of PdAg Nanoparticles during the Polyol Process in the Ethanol Electrooxidation Reaction

    Get PDF
    This work reports the effect of reduction temperature during the synthesis of PdAg catalysts through the polyol process and their evaluation in the ethanol electrooxidation reaction (EOR). The characterization was performed using Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD). The electrochemical evaluation for the ethanol electrooxidation reaction was implemented in alkaline medium using chronoamperometry (CA) and cyclic voltammetry (CV). An important effect of the reduction temperature on electroactivity and catalytic stability was observed: both the maximum current density and the catalytic stability were higher in the catalyst synthesized at the highest temperature (135°C). This performance was associated with the extent of the interaction between Pd and Ag which was measured in terms of the structural expansion of Pd

    Rotation curve bifurcations as indicators of close recent galaxy encounters

    Get PDF
    Rotation curves of interacting galaxies often show that velocities are either rising or falling in the direction of the companion galaxy. We seek to reproduce and analyse these features in the rotation curves of simulated equal-mass galaxies suffering a one-to-one encounter, as possible indicators of close encounters. Using simulations of major mergers in 3D, we study the time evolution of these asymmetries in a pair of galaxies, during the first passage. Our main results are: (a) the rotation curve asymmetries appear right at pericentre of the first passage, (b) the significant disturbed rotation velocities occur within a small time interval, of ~ 0.5 Gyr h^-1, and therefore the presence of bifurcation in the velocity curve could be used as an indicator of the pericentre occurrence. These results are in qualitative agreement with previous findings for minor mergers and fly-byes.Comment: 4 pages, 7 figure

    Implementation of a 10.24 GS/s 12-bit Optoelectronics Analog-to-Digital Converter Based on a Polyphase Demultiplexing Architecture

    Get PDF
    AbstractIn this paper we present the practical implementation of a high-speed polyphase sampling and demultiplexing architecture for optoelectronics analog-to-digital converters (OADCs). The architecture consists of a one-stage divide-by-eight decimator circuit where optically-triggered samplers are cascaded to sample an analog input signal, and demultiplex different phases of the sampled signal to yield low data rate for electronic quantization. Electrical-in to electrical-out data format is maintained through the sampling, demultiplexing and quantization processes of the architecture thereby avoiding the need for electrical-to-optical and optical-to-electrical signal conversions. We experimentally demonstrate a 10.24 giga samples per second (GS/s), 12-bit resolution OADC system comprising the optically-triggered sampling circuits integrated with commercial electronic quantizers. Measurements performed on the OADC yielded an effective bit resolution (ENOB) of 10.3 bits, spurious free dynamic range (SFDR) of -32 dB and signal-to-noise and distortion ratio (SNDR) of 63.7 dB

    Use of time-of-flight mass spectrometry for large screening of organic pollutants in surface waters and soils from a rice production area in Colombia

    Get PDF
    The irrigate district of Usosaldaña, an important agricultural area in Colombia mainly devoted to rice crop production, is subjected to an intensive use of pesticides. Monitoring these compounds is necessary to know the impact of phytosanitary products in the different environmental compartments. In this work, surface water and soil samples from different sites of this area have been analyzed by applying an analytical methodology for large screening based on the use of time-of-flight mass spectrometry (TOF MS) hyphenated to liquid chromatography (LC) and gas chromatography (GC). Several pesticides were detected and unequivocally identified, such as the herbicides atrazine, diuron or clomazone. Some of their main metabolites and/or transformation products (TPs) like deethylatrazine (DEA), deisopropylatrazine (DIA) and 3,4-dichloroaniline were also identified in the samples. Among fungicides, carbendazim, azoxystrobin, propiconazole and epoxiconazole were the most frequently detected. Insecticides such as thiacloprid, or p,p′-DDT metabolites (p,p′-DDD and p,p′-DDE) were also found. Thanks to the accurate-mass full-spectrum acquisition in TOF MS it was feasible to widen the number of compounds to be investigated to other families of contaminants. This allowed the detection of emerging contaminants, such as the antioxidant 3,5-di-tertbutyl-4-hydroxy-toluene (BHT), its metabolite 3,5-di-tert-butyl-4-hydroxy-benzaldehyde (BHT-CHO), or the solar filter benzophenone, among other

    An Event-driven SOA-based Platform for Energy-efficiency Applications in Buildings

    Get PDF
    The topic of optimization of building operation is attracting significant interest in the community: monitoring of relevant Key Performance Indicators can help enhance state awareness and understanding; fault detection and identification can help identify irregular and ineffective operational modes; and, advanced control design techniques can yield effective/optimized operation with regards to energy performance and thermal comfort. Despite significant effort on development of algorithmic and methodological approaches to address these problems, the inherent complexity associated with practical demonstrations, has precluded testing and implementation of such approaches in realistic contexts. Within this paper, an event-driven Service-Oriented Architecture platform, is developed to address this gap and help facilitate the provision of advanced energyefficiency and energy-management services in buildings. The use of the Industry Foundation Classes provides a standardized data-model for describing the building and its components, while the use of Model View definitions is employed to define the exchange requirements for proper software component interoperability. Data collection and homogenization from the building is addressed through an abstraction layer, capable of hiding many of the intricacies and providing a clean interface for the development of building services. An exemplary application of the proposed architecture in a real office building in Greece is presented

    The Role of Redox Dysregulation in the Inflammatory Response to Acute Myocardial Ischaemia-reperfusion Injury - Adding Fuel to the Fire

    Get PDF
    Background: The inflammatory response to acute myocardial ischaemia/ reperfusion injury (IRI) plays a critical role in determining myocardial infarct (MI) size, and subsequent post-MI left ventricular (LV) remodelling, making it a potential therapeutic target for improving clinical outcomes in patients presenting with an acute myocardial infarction (AMI). Recent experimental studies using advanced imaging and molecular techniques, have yielded new insights into the mechanisms through which reactive oxygen species (ROS) contribute to the inflammatory response induced by acute myocardial IRI - “adding fuel to the fire”. The infiltration of inflammatory cells into the MI zone, leads to elevated myocardial concentrations of ROS, cytokine release, and activation of apoptotic and necrotic death pathways. Anti-oxidant and anti-inflammatory therapies have failed to protect the heart against acute myocardial IRI. This may be, in part, due to a lack of understanding of the time course, nature and mechanisms of the inflammation and redox dysregulation, which occur in the setting of acute myocardial IRI. Conclusion: In this article, we examine the inflammatory response and redox dysregulation induced by acute myocardial IRI, and highlight potential therapeutic options for targeting redox dysregulation, in order to attenuate the detrimental effects of the inflammatory response following an AMI, so as to reduce MI size and prevent heart failure

    Occurrence of antibiotics and bacterial resistance in wastewater and sea water from the Antarctic

    Get PDF
    The potential presence of introduced antibiotics in the aquatic environment is a hot topic of concern, particularly in the Antarctic, a highly vulnerable area protected under the Madrid protocol. The increasing presence of human population, especially during summer, might led to the appearance of pharmaceuticals in wastewater. The previous discovery of Escherichia coli strains resistant to antibiotics in sea water and wastewater collected in King George Island motivated our investigation on antibiotics occurrence in these samples. The application of a multi-residue LCMS/MS method for 20 antibiotics, revealed the presence of 8 compounds in treated wastewater, mainly the quinolones ciprofloxacin and norfloxacin (92% and 54% of the samples analyzed, average concentrations 0.89 μg/L and 0.75 μg/L, respectively) and the macrolides azithromycin and clarithromycin (15% positive samples, and average concentrations near 0.4 μg/L), and erythromycin (38% positive samples, average concentration 0.003 μg/L). Metronidazole and clindamycin were found in one sample, at 0.17 and 0.1 μg/L, respectively; and trimethoprim in two samples, at 0.001 μg/L. Analysis of sea water collected near the outfall of the wastewater discharges also showed the sporadic presence of 3 antibiotics (ciprofloxacin, clindamycin, trimethoprim) at low ng/L level, illustrating the impact of pharmaceuticals consumption and the poor removal of these compounds in conventional WWTPs. The most widespread antibiotic in sea water was ciprofloxacin, which was found in 15 out of 34 sea water samples analyzed, at concentrations ranging from 4 to 218 ng/L. Bacteria resistance was observed for some antibiotics identified in the samples (e.g. trimetropim and nalidixic acid –a first generation quinolone). However, resistance to some groups of antibiotics could not be correlated to their presence in the water samples due to analytical limitations (penicillins, tetraciclines). On the contrary, for some groups of antibiotics detected in samples (macrolides), the antibacterial activity against E. Coli was not investigated because these antibiotics do not include this bacterial species in their spectrum of activity. Our preliminary data demonstrate that antibiotics occurrence in the Antarctic aquatic environment is an issue that needs to be properly addressed. Periodical monitoring of water samples and the implementation of additional treatments in the WWTPs are recommended as a first step to prevent potential problems related to the presence of antibiotics and other emerging contaminants in the near future in Antarctica
    corecore