3,621 research outputs found
Six weeks of conditioning exercise increases total, but not free testosterone in lifelong sedentary aging men
Introduction: Advancing age is associated with a gradual decline in circulating androgens, and the putative role of exercise training on systemic androgens remains to be adequately defined.
Methods: The present investigation examined the impact of 6 weeks of supervised exercise training on resting levels of systemic hormones in a cohort of lifelong sedentary men [SED (n = 28), 62.5 ± 5.3 years], compared with a positive control group of age-matched lifelong exercisers [LE (n = 20), 60.4 ± 4.7 years, >30 years training history]. Blood hormones were sampled pre- and post-intervention from an antecubital forearm vein and analysed using electrochemiluminescent immunoassay. Cardiorespiratory fitness () was determined via indirect calorimetry during an incremental cycle test to volitional exhaustion.
Results: Analysis of variance (ANOVA) revealed a lack of significant change in any parameter amongst LE, whilst SED experienced a significant exercise-induced improvement in cardiorespiratory fitness and total testosterone (all p 0.05) amongst SED.
Conclusions: Although resting levels of systemic total testosterone increased in response to 6 weeks of exercise training, increases in SHBG negated any potential relationship between calculated-free or bioavailable testosterone. These findings indicate that increases in bioavailable testosterone fraction are not required for cardiorespiratory fitness improvements in aging men
Electrical Machine Topologies: Hottest Topics in the Electrical Machine Research Community
In this article, the state of the art in electrical machine design is outlined underlining the problems and challenges to be solved by engineers. As highlighted in this article, even if electrical machine design is often considered a mature issue from the technical and technological point of view, every year, new progresses and steps forward are made. New and more sophisticated design tools can be used worldwide, and innovative manufacturing processes, new insulation materials, and higher performance magnetic materials are available on the market. In addition, the evolution of the hardware used in digital control and new powerful power electronic devices represents a constant stimulus to improve the performance of electrical machines and reintroduce electrical machine structures that were not adopted in the past due to technological and technical constraints. As shown in this article, electrical machine design is an evergreen topic, and its importance is rising more each year under the push of more energy-saving requirements and higher-efficiency systems for electromechanical conversion. A green world will not be possible without electrical machines
Results from the CBC3 readout ASIC for CMS 2S-modules
The CBC3 is the latest version of the CMS Binary Chip for readout of the outer radial region of the upgraded CMS Tracker at the High Luminosity LHC. This 254-channel, 130 nm CMOS ASIC is designed to be bump-bonded to a substrate to which sensors will be wire-bonded. It will instrument double-layer 2S-modules, containing two overlaid silicon microstrip sensors, aligned with a parallel orientation. On-chip logic identifies Level-1 trigger primitives from high transverse-momentum tracks by selecting correlated clusters in the two sensors. The CBC3 was delivered in late 2016; wafer probing and performance tests have been carried out. Several prototype modules using the CBC3 have been produced and tested in the lab and in different beams. The results show that the CBC3 satisfies CMS requirements and only small corrections are needed for the final version of the chip for production
Dynamic Muscle Fatigue Evaluation in Virtual Working Environment
Musculoskeletal disorder (MSD) is one of the major health problems in
mechanical work especially in manual handling jobs. Muscle fatigue is believed
to be the main reason for MSD. Posture analysis techniques have been used to
expose MSD risks of the work, but most of the conventional methods are only
suitable for static posture analysis. Meanwhile the subjective influences from
the inspectors can result differences in the risk assessment. Another
disadvantage is that the evaluation has to be taken place in the workshop, so
it is impossible to avoid some design defects before data collection in the
field environment and it is time consuming. In order to enhance the efficiency
of ergonomic MSD risk evaluation and avoid subjective influences, we develop a
new muscle fatigue model and a new fatigue index to evaluate the human muscle
fatigue during manual handling jobs in this paper. Our new fatigue model is
closely related to the muscle load during working procedure so that it can be
used to evaluate the dynamic working process. This muscle fatigue model is
mathematically validated and it is to be further experimental validated and
integrated into a virtual working environment to evaluate the muscle fatigue
and predict the MSD risks quickly and objectively
Peripheral Sensory Neuropathy Associates With Micro- or Macroangiopathy: Results from a population-based study of type 2 diabetic patients in Sweden
OBJECTIVE—To assess associations between peripheral sensory neuropathy (PSN) and other diabetes-related complications
Core components for effective infection prevention and control programmes: new WHO evidence-based recommendations
Abstract
Health care-associated infections (HAI) are a major public health problem with a significant impact on morbidity, mortality and quality of life. They represent also an important economic burden to health systems worldwide. However, a large proportion of HAI are preventable through effective infection prevention and control (IPC) measures. Improvements in IPC at the national and facility level are critical for the successful containment of antimicrobial resistance and the prevention of HAI, including outbreaks of highly transmissible diseases through high quality care within the context of universal health coverage. Given the limited availability of IPC evidence-based guidance and standards, the World Health Organization (WHO) decided to prioritize the development of global recommendations on the core components of effective IPC programmes both at the national and acute health care facility level, based on systematic literature reviews and expert consensus. The aim of the guideline development process was to identify the evidence and evaluate its quality, consider patient values and preferences, resource implications, and the feasibility and acceptability of the recommendations. As a result, 11 recommendations and three good practice statements are presented here, including a summary of the supporting evidence, and form the substance of a new WHO IPC guideline
Exploring irrigation and water supply technologies for smallholder farmers in the Mediterranean region
Water security is a hot topic all over the world, due to global warming, climate change, natural calamities such as droughts and floods, overuse of water, and other factors. Water issues have been scientifically investigated from several perspectives, namely institutional, economic, social, environmental, managerial, and technological. However, the technological aspects of irrigation and water supply for smallholder farmers in the Mediterranean region have not been adequately addressed. This paper explores irrigation and water supply technologies for smallholder farmers in the selected Mediterranean countries (Egypt, Malta, Morocco, and Portugal). The methods of analysis are literature review, fieldwork, and observation. The literature survey reveals that Mediterranean countries share many common features in terms of climate, water and land resources, and development issues. Nevertheless, the selected countries in the Mediterranean region (Egypt, Malta, Morocco, and Portugal) differ in terms of type of crops, water management regulations, labor force availability, financial sustainability, and economic approaches. These remarks signal the need for applying a specific approach in selecting a technology for irrigation and water supply according to the regional context. Additionally, the financial and economic perspectives of the three key technologies (i.e., SLECI, desalination technology, and engineering constructed wetlands) require further analysis.This research carried out within the project MED-WET “Improving MEDiterranean irrigation and Water supply for smallholder farmers by providing Efficient, low-cost and nature-based
Technologies and practices” (Project ID 1646) funded by Partnership for Research and Innovation in
the Mediterranean Area (PRIMA) program.info:eu-repo/semantics/publishedVersio
Enhancing nano-scale computational fluid dynamics with molecular pre-simulations: unsteady problems and design optimisation
We demonstrate that a computational fluid dynamics (CFD) model enhanced with molecular-level information can accurately predict unsteady nano-scale flows in non-trivial geometries, while being efficient enough to be used for design optimisation. We first consider a converging–diverging nano-scale channel driven by a time-varying body force. The time-dependent mass flow rate predicted by our enhanced CFD agrees well with a full molecular dynamics (MD) simulation of the same configuration, and is achieved at a fraction of the computational cost. Conventional CFD predictions of the same case are wholly inadequate. We then demonstrate the application of enhanced CFD as a design optimisation tool on a bifurcating two-dimensional channel, with the target of maximising mass flow rate for a fixed total volume and applied pressure. At macro scales the optimised geometry agrees well with Murray’s Law for optimal branching of vascular networks; however, at nanoscales, the optimum result deviates from Murray’s Law, and a corrected equation is presented
The impact of remote ischemic preconditioning on cardiac biomarker and functional response to endurance exercise.
Remote ischemic preconditioning (RIPC; repeated short reversible periods of ischemia) protects the heart against subsequent ischemic injury. We explored whether RIPC can attenuate post-exercise changes in cardiac troponin T (cTnT) and cardiac function in healthy individuals. In a randomized, crossover design, 14 participants completed 1-h cycling time trials (TT) on two separate visits; preceded by RIPC (arms/legs, 4 × 5-min 220 mmHg), or SHAM-RIPC (20 mmHg). Venous blood was sampled before and 0-, 1-, and 3-h post-exercise to assess high sensitivity (hs-)cTnT and brain natriuretic peptide (NT-proBNP). Echocardiograms were performed at the same time points to assess left and right ventricular systolic (ejection fraction; EF and right ventricular fractional area change; RVFAC, respectively) and diastolic (early transmitral flow velocities; E) function. Baseline hs-cTnT was not different between RIPC and SHAM. Post-exercise hs-cTnT levels were consistently lower following RIPC (18 ± 3 vs 21 ± 3; 19 ± 3 vs 23 ± 3; and 20 ± 2 vs 25 ± 2 ng/L at 0, 1 and 3-h post-exercise, respectively; P < 0.05). There was no main effect of time, trial, or interaction for NT-proBNP and left ventricular EF or RVFAC (all P < 0.05). A main effect of time was evident for E which transiently declined immediately after exercise to a similar level in both trials (0.85 ± 0.04 vs 0.74 ± 0.04 m/s, respectively; P < 0.05). In summary, RIPC was associated with lower hs-cTnT levels after exercise but there was no independent effect of RIPC for NT-proBNP or LV systolic and diastolic function. The lower hs-cTnT levels after RIPC suggests that further research should evaluate the role of ischemia in exercise-induced elevation in hs-cTnT
Longevity in mice: is stress resistance a common factor?
A positive relationship between stress resistance and longevity has been reported in a multitude of studies in organisms ranging from yeast to mice. Several mouse lines have been discovered or developed that exhibit extended longevities when compared with normal, wild-type mice of the same genetic background. These long-living lines include the Ames dwarf, Snell dwarf, growth hormone receptor knockout (Laron dwarf), IGF-1 receptor heterozygote, Little, α-MUPA knockout, p66shc knockout, FIRKO, mClk-1 heterozygote, thioredoxin transgenic, and most recently the Klotho transgenic mouse. These mice are described in terms of the reported extended lifespans and studies involving resistance to stress. In addition, caloric restriction (CR) and stress resistance are briefly addressed for comparison with genetically altered mice. Although many of the long-living mice have GH/IGF-1/insulin signaling-related alterations and enhanced stress resistance, there are some that exhibit life extension without an obvious link to this hormone pathway. Resistance to oxidative stress is by far the most common system studied in long-living mice, but there is evidence of enhancement of resistance in other systems as well. The differences in stress resistance between long-living mutant and normal mice result from complex interrelationships among pathways that appear to coordinate signals of growth and metabolism, and subsequently result in differences in lifespan
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