1,442 research outputs found

    THE EVOLUTION ACROSS AGES OF EFFICIENCY AND ECONOMY OF (ASSISTED) HUMAN LOCOMOTION AND EXERCISE

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    Human evolution and ingenuity both collaborated in providing biological/technological tools to move faster, despite of the same actuator, and to better adapt our locomotion to very different environments. While evolution resulted in a versatile musculo-skeletal system featuring optimization and energy-saving mechanisms to produce force and work more effectively, humans also invented passive tools, particularly in the last 4-5 millennia, allowing to moving faster and more economically on land, on/under water and in the air. Among the most featured examples: bone skating on ice, ancient cross-country skiing, bicycling, rowing. But also hand-held masses (Minetti & Ardigo, 2002) enhanced standing long jump and bows/crossbows made us throwing objects at longer distances (a hand-thrown arrow barely reach 25 m, while with a modern bow the distance exceeds 1.3 km). In the past few years we reviewed the historic evolution of passive tools devoted to enhance human locomotion (Minetti, 2004; Ardigo et al., 2005). Sometimes we built replicas of ancient tools (as in cycling - Minetti et al., 2001, cross-country skiing - Formenti et al., 2005 and ice skating - Formenti & Minetti, 2006), in other cases we used modern tools (as fins - Zamparo et al., 2002) in order to study, through biomechanical and metabolic experiments, the progressive adaptation of (the same) muscle to the different machines and environments. The focus of my presentation will be on how limitations of the musculo-skeletal system have been attenuated both inside (gear ratio, tendons) and outside (crank, gears, poles, skis, fins) the body. The relevance into the necessary mechanical work, the economy of transport and the related efficiency of motion/locomotion will be discussed

    Nanosized patterns as reference structures for macroscopic transport properties and vortex phases in YBCO films

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    This paper studies the striking correlation between nanosized structural patterns in YBCO films and macroscopic transport current. A nanosized network of parallel Josephson junctions laced by insulating dislocations is almost mimicking the grain boundary structural network. It contributes to the macroscopic properties and accounts for the strong intergranular pinning across the film in the intermediate temperature range. The correlation between the two networks enables to find out an outstanding scaling law in the (Jc,B) plane and to determine meaningful parameters concerning the matching between the vortex lattice and the intergranular defect lattice. Two asymptotic behaviors of the pinning force below the flux flow regime are checked: the corresponding vortex phases are clearly individuated.Comment: 4 pages, 4 figure

    Acute and long-term effects of ACE inhibition on renal haemodynamics in glomerular and interstitial nephropathies

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    Background Angiotensin-converting enzyme (ACE) inhibitors are the drugs of choice for the treatment of hypertension in patients with non-diabetic nephropathies. However, not every trial has reported better results with ACE inhibitors (ACE-I) than with other drugs. This study investigates whether the acute and chronic effects of ACE inhibition on renal and glomerular haemodynamics are similar in glomerular and interstitial nephropathies. Methods We studied 20 hypertensive patients, on their usual diet, with mild-to-moderate chronic renal failure secondary to non-diabetic nephropathy. After a three-week wash out period, we determined plasma clearances of para-amino-hippurate and inulin before, and after acute oral administration of either enalapril or ramipril. This same test was carried out after one and two years of treatment with the same drug. Results Acute ACE inhibition causes a decrease of renal perfusion, glomerular filtration and pressure with an increase of afferent resistances. Long-term ACE inhibition is associated only with a decrease in renal perfusion, with a non-significant tendency to higher filtration fraction and lower afferent resistances. All the renal haemodynamic modifications mentioned above are present only in patients with glomerular diseases. Conclusions Renal and glomerular haemodynamic responses are not similar after acute and chronic ACE inhibition. Only patients with glomerular diseases show acute or long-term responses to ACE inhibition

    Optimization of SPME/GC-MS analytical method using Response Surface Methodology for pesticides monitoring in aqueous matrices

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    Emerging pollutants are a type of contaminants that can occur in water sources. They can be defined as any synthetic or naturally occurring chemical or microorganism that is not usually monitored or regulated in the environment and have the potential to cause detrimental ecological and human health impacts. These compounds can be found in the environment in very low concentrations, at scales ranging from nanograms to micrograms per liter. Pesticides are an important group of emerging pollutants due to the continuous increase in their use in agricultural production process to control diseases, pests and weedsThe authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020).info:eu-repo/semantics/publishedVersio

    Health-related quality of life and functional changes in DMD:A 12-month longitudinal cohort study

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    Family caregivers of people with amyotrophic lateral sclerosis (ALS) live stressful lives in which they spend most of their time caring for their loved ones and managing difficult situations, thereby reducing the time spent in taking care of themselves. This situation may last several years. Previous literature has widely highlighted that this situation reduces caregivers' quality of life and increases their psychological distress and risk of health problems, but there is a lack of studies that focus on psychological interventions for these situations. This qualitative study examined a pilot experience of two mutual support groups for family caregivers of people with ALS. The aim was to identify caregivers' needs, the prominent aspects of their experience, and to understand whether and how this intervention strategy might help them. Six partners (four men and two women) and six adult children (five women and one man) participated in the groups, which were conducted in northern Italy. After the support groups finished, participants underwent semi-structured interviews. The authors conducted a content analysis of the transcripts of the interviews and the 20 group sessions. The thematic areas identified were "caregiving," "being the son/daughter of a person with ALS," "being the partner of a person with ALS," "group experience" and "group evaluation." The caregiving experience was profoundly different depending on whether the caregiver was a son/daughter or a partner of a patient with ALS. Moreover, comparison with peers and mutual support helped participants to better cope with ALS and its consequences, to improve their care for their relatives and to overcome typical caregiver isolation. These results suggest the usefulness of involving communities in caregiver support in order to create new networks and activate personal and social resources for well-being

    Dynamic contrast-enhanced magnetic resonance imaging of the wrist in early arthritis

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    Objectives: MRI has been proposed as the imaging method of choice to evaluate the long-term outcome in patients with early arthritis. The role of dynamic MRI, performed at presentation, in predicting the outcome of patients with early arthritis has been addressed in the present study. Methods: 39 patients with early arthritis, involving at least one wrist, were studied with clinical visits and laboratory investigations, every 3 months. Dynamic MRI was performed with a low-field (0.2T), extremity-dedicated machine (Artoscan, Esaote, Genova, Italy) equipped with a permanent magnet and with a dedicated hand and wrist coil. During the intravenous injection of Gd-DTPA, twenty consecutive fast images of 3 slices of the wrist were acquired. The synovial contrast enhancement ratio was calculated both as rate of early enhancement (REE) per second during the first 55" and as relative enhancement (RE) at t seconds. Results: In our cohort of patients, REE and RE were significantly lower than those observed in a historical cohort of 36 patients with active rheumatoid arthritis. In univariate analysis, low RE predicted complete remission of arthritis. In multivariate analysis, fulfillment of RA criteria during follow-up was predicted by high RE. The need for immunosuppressive treatment at the end of follow-up was predicted by both low RE and high REE. Conclusions: Dynamic MRI may be used to predict several outcomes of early arthritis involving the wris

    A new apparatus for deep patterning of beam sensitive targets by means of high-energy ion beam

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    The paper reports on a high precision equipment designed to modify over 3-dimensions (3D) by means of high-energy gold ions the local properties of thin and thick films. A target-moving system aimed at creating patterns across the volume is driven by an x-y writing protocol that allows one to modify beam sensitive samples over micrometer-size regions of whatever shape. The apparatus has a mechanical resolution of 15 nm. The issue of the local fluence measurement has been particularly addressed. The setup has been checked by means of different geometries patterned on beam sensitive sheets as well as on superconducting materials. In the last case the 3D modification consists of amorphous nanostructures. The nanostructures create zones with different dissipative properties with respect to the virgin regions. The main analysis method consists of magneto-optical imaging that provides local information on the electrodynamics of the modified zones. Features typical of non-linear current flow hint at which pattern geometry is more functional to applications in the framework of nanostructures across superconducting films.Comment: 7 page
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