536 research outputs found

    EUTELSAT: Europe\u27s Satellite Telecommunications

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    In the 1950s long distance telephone communication by wire or Herz circuit was extremely limited and usually very expensive. In 1956, the installation of the first transatlantic telephone cable, TAT 1, signaled the beginning of the present era in intercontinental telecommunications. However, it soon became apparent that underwater cables would not meet the ever-increasing demand for communications created by expanding global economic activity. At the same time, radio communications also experienced growing demand, and suffered from overcrowded frequencies. It was therefore natural that the first application of telecommunications technology in space focused on the improvement of intercontinental circuits

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    Visceral fat mass determination in rodent: validation of dual-energy x-ray absorptiometry and anthropometric techniques in fat and lean rats

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    <p>Abstract</p> <p>Background</p> <p>Because abdominal obesity is predisposed to various metabolic disorders, it is of major importance to assess and track the changes with time of this specific fat mass. The main issue for clinicians or researchers is to use techniques for assessing abdominal fat deposition and its accumulation or changes over time, without sacrificing of experimental subjects. In the rat, techniques to investigate in-vivo visceral fat mass are lacking. The purpose of the study was to validate indirect Dual-energy X-ray Absorptiometry technique and abdominal circumference measurement as tools to predict visceral adipose tissue in rats.</p> <p>Forty-three Wistar male rats from different body weight, fat mass and ages were included in the study. Visceral fat mass was assessed by weighing the total perirenal and peri-epididymal adipose tissues after dissection. Statistical methods were used to discriminate the best region of interest allowing the in-vivo measure of Central Fat Mass by DXA. Abdominal circumference was measured at the same time as the DXA scan.</p> <p>Results</p> <p>A region of interest including Central Fat Mass from the whole body DXA scan (extending from L2 to L5 vertebrae), correlated strongly with <it>ex-vivo </it>Fat Mass (r = 0.94, p < 0.001). Abdominal circumference correlated significantly with <it>ex-vivo </it>Fat Mass (r = 0.82, p < 0.001) and Central Fat Mass (0.90, p < 0.001) in the whole group of rats. When dividing the whole group into lean and fat rats, correlations remained significant between Central Fat Mass and <it>ex-vivo </it>Fat Mass but disappeared for the lean group between abdominal circumference and <it>ex-vivo </it>Fat Mass.</p> <p>Conclusions</p> <p>This study validates the Central Fat Mass determined by DXA as a non-sacrificial technique to assess visceral fat for in-vivo investigations in rats. The abdominal circumference measure appears useful in studying overweight or obese rats. These two techniques could be convenient tools in follow-up and longitudinal studies.</p

    Blood lipids and adipokines concentrations during a 6-month nutritional and physical activity intervention for metabolic syndrome treatment

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    <p>Abstract</p> <p>Background</p> <p>To report changes in body weight, total and central fat mass, metabolic, hormonal and inflammatory parameters in overweight people who participated in a six months weight loss intervention associating diet management and exercise.</p> <p>Subjects and Methods</p> <p>Fourteen subjects (10 M, 4 F, mean age 62.9 ± 6.9 years, BMI 30.4+/- 3.8 kg/m<sup>2</sup>) presenting the characteristics of the Metabolic Syndrome (MS) were included in the survey. They followed a three weeks (D0 to D20) cure in a medical establishment and a six months (D20 to M3 and M6) follow up at home. During the cure, they receive a balanced diet corresponding to 500 Kcal deficit vs their dayly energy expenditure (DEE) and they exercised 2 to 3 hours per day.</p> <p>At D0, D20, M3 and M6, body composition (lean mass, total and central fat mass) was analyzed with DEXA, blood pressure was taken and blood was collected to evaluate glycaemia, triglycerides, total, LDL and HDL cholesterol, insulin, leptin and adiponectin levels, CRP and pro-inflammatory interleukines IL1, IL.6 and TNFalpha.</p> <p>Results</p> <p>All parameters listed above except the cytokine were improved at D20, so that 4 subjects among 14 still presented the MS. After returning to home, these parameters remained stable.</p> <p>Conclusion</p> <p>The efficacy of therapeutic lifestyle modifications with education and exercise and diet was demonstrated, but the compliance to the new healthy lifestyle initiated during the cure was not optimal.</p

    Heart rate variability as a possible predictor of sport performance in junior rhythmic gymnastics

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    BACKGROUND: Heart rate variability may reveal sensitive information about the athletes’ physiological adaptation when exercising for sport performance. OBJECTIVE: The aim of this study was to demonstrate whether heart rate variability (HRV) measurements were able to predict sport results and determine which type of measurements, at rest or during routines, were relevant in anticipating the performance. METHOD: Ten female gymnasts, aged 11–14 years old, and 16 age-matched non-active adolescents participated in this study. HRV was measured at rest for 10 minutes and throughout the training routines one week prior to competition. Correlations and multivariate analysis determined the parameters predicting performance. Significance was set at p⩽ 0.05. Results: At rest, the gymnasts displayed higher HRV values than controls. At rest, sympathetic parameters correlated with sport results whereas no correlation was observed during routines. The magnitude of the predictive factors highlighted the importance of Ln SD2 (coefficient =−117, 95CI −130 to −106), Ln RMSSD (coefficient =−24.5, 95CI −29.2 to −19.8), Ln pNN50 (coefficient =−10.7, 95CI −11.5 to −9.9), and Ln Total power (coefficient =−2.5, 95CI −13.4 to −11.5). CONCLUSIONS: HRV at rest may predict results in competition, being a complementary tool for coaches

    Efficacy-based perspective to overcome reduced opioid analgesia of advanced painful diabetic neuropathy in rats

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    Reduction of the opioid analgesia in diabetic neuropathic pain (DNP) results from mu-opioid receptor (MOR) reserve reduction. Herein, we examined the antinociceptive and antiallodynic actions of a novel opioid agonist 14-O-methymorphine-6-O-sulfate (14-O-MeM6SU), fentanyl and morphine in rats with streptozocin-evoked DNP of 9-12 weeks following their systemic administration. The antinociceptive dose-response curve of morphine but not of 14-O-MeM6SU or fentanyl showed a significant right-shift in diabetic compared to non-diabetic rats. Only 14-O-MeM6SU produced antiallodynic effects in doses matching antinociceptive doses obtained in non-diabetic rats. Co-administered naloxone methiodide (NAL-M), a peripherally acting opioid receptor antagonist failed to alter the antiallodynic effect of test compounds, indicating the contribution of central opioid receptors. Reduction in spinal MOR binding sites and loss in MOR immunoreactivity of nerve terminals in the spinal cord and dorsal root ganglia in diabetic rats were observed. G-protein coupling assay revealed low efficacy character for morphine and high efficacy character for 14-O-MeM6SU or fentanyl at spinal or supraspinal levels (E-max values). Furthermore, at the spinal level only 14-O-MeM6SU showed equal efficacy in G-protein activation in tissues of diabetic- and non-diabetic animals. Altogether, the reduction of spinal opioid receptors concomitant with reduced analgesic effect of morphine may be circumvented by using high efficacy opioids, which provide superior analgesia over morphine. In conclusion, the reduction in the analgesic action of opioids in DNP might be a consequence of MOR reduction, particularly in the spinal cord. Therefore, developing opioids of high efficacy might provide analgesia exceeding that of currently available opioids

    Impact of an obesogenic diet program on bone densitometry, micro architecture and metabolism in male rat.

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    International audienceABSTRACT: Background The relationships between fat mass and bone tissue are complex and not fully elucidated. A high-fat/high-sucrose diet has been shown to induce harmful effects on bone micro architecture and bone biomechanics of rat. When such diet leads to obesity, it may induce an improvement of biomechanical bone parameters in rodent. Here, we examined the impact of a high-fat/high-sucrose diet on the body composition and its resulting effects on bone density and structure in male rats. Forty three Wistar rats aged 7 months were split into 3 groups: 1 sacrificed before diet (BD, n=14); 1 subjected to 16 weeks of high-fat/high-sucrose diet (HF/HS, n=14); 1 subjected to standard diet (Control, n=15). Abdominal circumference and insulin sensitivity were measured and visceral fat mass was weighed. The bone mineral density (BMD) was analyzed at the whole body and tibia by densitometry. Microcomputed tomography and histomorphometric analysis were performed at L2 vertebrae and tibiae to study the trabecular and cortical bone structures and the bone cell activities. Osteocalcin and CTX levels were performed to assess the relative balance of the bone formation and resorption. Differences between groups have been tested with an ANOVA with subsequent Scheffe post-hoc test. An ANCOVA with global mass and global fat as covariates was used to determine the potential implication of the resulting mechanical loading on bone. RESULTS: The HF/HS group had higher body mass, fat masses and abdominal circumference and developed an impaired glucose tolerance compared to Control group (p<0.001). Whole body bone mass (p<0.001) and BMD (p<0.05) were higher in HF/HS group vs. Control group. The trabecular thickness at vertebrae and the cortical porosity of tibia were improved (p<0.05) in HF/HS group. Bone formation was predominant in HF/HS group while an unbalance bone favoring bone resorption was observed in the controls. The HF/HS and Control groups had higher total and abdominal fat masses and altered bone parameters vs. BD group. Conclusions The HF/HS diet had induced obesity and impaired glucose tolerance. These changes resulted in an improvement of quantitative, qualitative and metabolic bone parameters. The fat mass increase partly explained these observations

    Prática de artes marciais e densidade mineral óssea em adolescentes de ambos os sexos

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    The purpose of this study was to analyze the relationship between martial arts practice (judo, karate and kung-fu) and bone mineral density in adolescents.METHODS: The study was composed of 138 (48 martial arts practitioners and 90 non-practitioners) adolescents of both sexes, with an average age of 12.6 years. Bone mineral density was measured using Dual-Energy X-ray Absorptiometry in arms, legs, spine, trunk, pelvis and total. Weekly training load and previous time of engagement in the sport modality were reported by the coach. Partial correlation tested the association between weekly training load and bone mineral density, controlled by sex, chronological age, previous practice and somatic maturation. Analysis of covariance was used to compare bone mineral density values according to control and martial arts groups, controlled by sex, chronological age, previous practice and somatic maturation. Significant relationships between bone mineral density and muscle mass were inserted into a multivariate model and the slopes of the models were compared using the Student t test (control versus martial art).RESULTS: Adolescents engaged in judo practice presented higher values of bone mineral density than the control individuals (p-value=0.042; Medium Effect size [Eta-squared=0.063]), while the relationship between quantity of weekly training and bone mineral density was significant among adolescents engaged in judo (arms [r=0.308] and legs [r=0.223]) and kung-fu (arms [r=0.248] and spine [r=0.228]).CONCLUSIONS: Different modalities of martial arts are related to higher bone mineral density in different body regions among adolescents.O objetivo desse estudo foi analisar a relac¸ão entre a prática de artes marciais (judô, karatê e kung-fu) e a densidade mineral óssea em adolescentes. Métodos: O estudo foi composto por 138 adolescentes (48 praticantes de artes marciais e 90 não praticantes) de ambos os sexos, com idade média de 12,6 anos. A densidade mineral óssea foi medida usando absortometria radiológica de dupla energia em brac¸os, pernas, coluna, tronco, pelve e total. A carga de treinamento semanal e o tempo anterior de envolvimento na modalidade esportiva foram relatados pelo treinador. A correlac¸ão parcial testou a associac¸ão entre a carga semanal de treinamento e a densidade mineral óssea, controlada para sexo, idade cronológica, prática anterior e maturac¸ão somática. A análise de covariância foi utilizada para comparar os valores de densidade mineral óssea de acordo com os grupos controle e de artes marciais, controlados para sexo, idade cronológica, prática anterior e maturac¸ão somática. Associac¸ões significativas entre a densidade mineral óssea e a massa muscular foram inseridas em um modelo multivariado e as inclinac¸ões dos modelos foram comparadas usando o teste t de Student (controle versus arte marcial). Resultados: Os adolescentes envolvidos na prática de judô apresentaram valores maiores de densidade mineral óssea do que os indivíduos do grupo controle (p=0,042; tamanho de efeito médio [eta-quadrado=0,063]), enquanto a relac¸ão entre a quantidade de treinos semanais e a densidade mineral óssea foi significativa entre os adolescentes praticantes de judô (brac¸os [r=0,308] e pernas [r=0,223]) e kung-fu (brac¸os [r=0,248] e coluna [r=0,228]). Conclusões: Diferentes modalidades de artes marciais estão relacionadas com maior densidade mineral óssea em diferentes regiões do corpo em adolescentes

    Leptin levels were negatively associated with lumbar spine bone mineral content in children with overweight or obesity

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    Aim: Adipokines seem to play a role in bone morphogenesis, although this also depends on the mechanical forces applied to the skeleton. The aim was to assess the relationships of resting leptin and adiponectin with bone parameters and whether high muscular fitness levels affect these relationships in children with overweight or obesity. Methods: This cross-sectional study took part from 2014 to 2016 in Granada, Spain. Participants were recruited from University Hospitals, and we also used advertisements in local media and school contacts in the city. Adipokines were analysed in plasma. Muscular fitness was assessed by one repetition maximum in bench and leg press tests. Dual-energy X-ray absorptiometry was used to measure bone parameters. Results: We included 84 children (10.0 ± 1.2y; 63% boys) in this analysis. Leptin was negatively associated with lumbar spine bone mineral content (β = −0.162, p = 0.053)

    Concurrent agreement between an anthropometric model to predict thigh volume and dual-energy X-Ray absorptiometry assessment in female volleyball players aged 14-18 years

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    A variety of performance outputs are strongly determined by lower limbs volume and composition in children and adolescents. The current study aimed to examine the validity of thigh volume (TV) estimated by anthropometry in late adolescent female volleyball players. Dual-energy X-ray absorptiometry (DXA) measures were used as the reference method. Total and regional body composition was assessed with a Lunar DPX NT/Pro/MD+/Duo/Bravo scanner in a cross-sectional sample of 42 Portuguese female volleyball players aged 14-18 years (165.2 ± 0.9 cm; 61.1 ± 1.4 kg). TV was estimated with the reference method (TV-DXA) and with the anthropometric method (TV-ANTH). Agreement between procedures was assessed with Deming regression. The analysis also considered a calibration of the anthropometric approach. The equation that best predicted TV-DXA was: -0.899 + 0.876 × log10 (body mass) + 0.113 × log10 (TV-ANTH). This new model (NM) was validated using the predicted residual sum of squares (PRESS) method (R2PRESS = 0.838). Correlation between the reference method and the NM was 0.934 (95%CI: 0.880-0.964, Sy∙x = 0.325 L). A new and accurate anthropometric method to estimate TV in adolescent female volleyball players was obtained from the equation of Jones and Pearson alongside with adjustments for body mass.info:eu-repo/semantics/publishedVersio
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