589 research outputs found

    Do the effects of vitamin d supplementation on muscle strength differ according to age?

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    Introduction: Vitamin D plays an important role in musculoskeletal health and its use improves muscle strength. However, the effect of vitamin D use on muscle strength in women of different ages is yet to be investigated. Therefore, in this study, we aimed to evaluate the effect of vitamin D use on muscle strength in women of different age groups and determine the differences of muscle strength gain between age groups. Materials and Method: Sixty-three women with calcidiol levels<30 ng/mL were randomly assigned and stratified by their age group as follows: Group I (aged 40–49 years), Group II (aged 50–59 years) and Group III (aged 60–69 years). Calcidiol levels, body mass index, fat free mass, percent fat, grip strength, arm curl, chair stand and isokinetic concentric flexor and extensor peak torque and power at 60°•s−1 and 180°•s−1 were assessed at baseline and six months after oral cholecalciferol supplementation. Results: Vitamin D supplementation caused significant improvement in body mass index, arm curl, grip strength and knee flexor and extensor peak torque and power at 60°•s−1 and 180°•s−1 in all groups (p<0.05). Knee flexor power at 60°•s−1 and extensor power at 180°•s−1 were significantly higher in group I than in group III (p<0.025). Conclusion: Muscle strength in response to vitamin D supplementation increased in all age groups, and isokinetic muscle power was the highest in the youngest age group studied. © 2018, Geriatrics Society. All rights reserved

    INVESTIGATING HOW PARENTS, WHO GUIDE THEIR PRESCHOOL CHILDREN TOWARDS SPORTS, PERCEIVE SPORTS ACTIVITIES

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    Objectives: The aim of this study was to investigate parents’ expectations about general sport activities for their pre-school children. It is well documented that the awareness of sports knowledge of the parents are essential for the development of healthy life and acquiring a social dimension with a growth of healthy generations. Method: We administrated the ‘’Parents' Expectations of Their Children Questionnaire’’ developed by Keskin (2006). The questionnaire was a Likert type scale from ‘’totally agree’’ to ‘’totally disagree’’ and validity and reliability studies were reported by Keskin as Cronbach’s alpha was 0,86. A total of 125 participants (male; N = 39, Mage=35, 24 ± 5,48 , female; N = 86 and Mage=37,92 ± 6,65) were voluntarily participated from 10 different kinder gardens in Bursa province. The evaluation of the data was analysed with the Chi Square Test. Result: Our results revealed a statistical differences (p &lt; .05) according to the sex groups of parents ‘’I believe my child will gain good eating habits by getting involved with sports activities’’ and age groups of parents; ‘’I believe by getting involved with sport activities, my child will stay away from psychological stress’’. Conclusion: According to parents’ belief and their expectations, attending sports activities for children provides physical, cognitive and social development for them. Developing countries (as well as developed ones) that are aware of the role of the parents on development of human being via sport and exercise activities should take into account their expectations especially in terms of sports policies.  Article visualizations

    Thermal stability of electron traps in GaN grown by metalorganic chemical vapor deposition

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    Deep level transient spectroscopy was used to investigate the thermal stability of electron traps in n-type GaN grown by metalorganic chemical vapor deposition. The concentration of traps at 160 and at 500K increased more than fivefold over the course of several 700Kanneal cycles, while a peak at 320K increased by a factor of only 1.19. The increase in the trap concentration with repeated annealing might be due to a mobile trap or loss of passivant. Hydrogen is very likely present in high concentration in the epilayer, and its passivating effects may be lost with annealing

    Prognostic factors of perioperative FLOT regimen in operable gastric and gastroesophageal junction tumors: real-life data (Turkish Oncology Group)

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    Background/aim: Perioperative FLOT regimen is a standard of care in locally advanced operable gastric and GEJ adenocarcinoma. We aimed to determine the efficacy, prognostic factors of perioperative FLOT chemotherapy in real-life gastric and GEJ tumors. Materials and methods: The data of patients who were treated with perioperative FLOT chemotherapy were retrospectively analyzed from 34 different oncology centers in Turkey. Baseline clinical and demographic characteristics, pretreatment laboratory values, histological and molecular characteristics were recorded. Results: A total of 441 patients were included in the study. The median of age our study population was 60 years. The majority of patients with radiological staging were cT3-4N(+) (89.9%, n = 338). After median 13.5 months (IQR: 8.5–20.5) follow-up, the median overall survival was NR (95% CI, NR to NR), and median disease free survival was 22.9 (95% CI, 18.6 to 27.3) months. The estimated overall survival at 24 months was 62%. Complete pathological response (pCR) and near pCR was achieved in 23.8% of all patients. Patients with lower NLR or PLR have significantly longer median OS (p = 0.007 and p = 0.033, respectively), and patients with lower NLR have significantly longer median DFS (p = 0.039), but PLR level did not affect DFS (p = 0.062). The OS and DFS of patients with better ECOG performance scores and those who could receive FLOT as adjuvant chemotherapy instead of other regimens were found to be better. NLR was found to be independent prognostic factor for OS in the multivariant analysis. At least one adverse event reported in 57.6% of the patients and grade 3–4 toxicity was seen in 23.6% patients. Conclusion: Real-life perioperative FLOT regimen in operable gastric and GEJ tumors showed similar oncologic outcomes compared to clinical trials. Better performance status, receiving adjuvant chemotherapy as same regimen, low grade and low NLR and PLR improved outcomes in real-life. However, in multivariate analysis, only NLR affected OS. © TÜBİTAK

    Seismic constraints on the radial dependence of the internal rotation profiles of six Kepler subgiants and young red giants

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    Context : We still do not know which mechanisms are responsible for the transport of angular momentum inside stars. The recent detection of mixed modes that contain the signature of rotation in the spectra of Kepler subgiants and red giants gives us the opportunity to make progress on this issue. Aims: Our aim is to probe the radial dependance of the rotation profiles for a sample of Kepler targets. For this purpose, subgiants and early red giants are particularly interesting targets because their rotational splittings are more sensitive to the rotation outside the deeper core than is the case for their more evolved counterparts. Methods: We first extract the rotational splittings and frequencies of the modes for six young Kepler red giants. We then perform a seismic modeling of these stars using the evolutionary codes CESAM2k and ASTEC. By using the observed splittings and the rotational kernels of the optimal models, we perform inversions of the internal rotation profiles of the six stars. Results: We obtain estimates of the mean rotation rate in the core and in the convective envelope of these stars. We show that the rotation contrast between the core and the envelope increases during the subgiant branch. Our results also suggest that the core of subgiants spins up with time, contrary to the RGB stars whose core has been shown to spin down. For two of the stars, we show that a discontinuous rotation profile with a deep discontinuity reproduces the observed splittings significantly better than a smooth rotation profile. Interestingly, the depths that are found most probable for the discontinuities roughly coincide with the location of the H-burning shell, which separates the layers that contract from those that expand. These results will bring observational constraints to the scenarios of angular momentum transport in stars.Comment: Accepted in A&A, 27 pages, 18 figure

    Stellar ages and convective cores in field main-sequence stars: first asteroseismic application to two Kepler targets

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    Using asteroseismic data and stellar evolution models we make the first detection of a convective core in a Kepler field main-sequence star, putting a stringent constraint on the total size of the mixed zone and showing that extra mixing beyond the formal convective boundary exists. In a slightly less massive target the presence of a convective core cannot be conclusively discarded, and thus its remaining main-sequence life time is uncertain. Our results reveal that best-fit models found solely by matching individual frequencies of oscillations corrected for surface effects do not always properly reproduce frequency combinations. Moreover, slightly different criteria to define what the best-fit model is can lead to solutions with similar global properties but very different interior structures. We argue that the use of frequency ratios is a more reliable way to obtain accurate stellar parameters, and show that our analysis in field main-sequence stars can yield an overall precision of 1.5%, 4%, and 10% in radius, mass and age, respectively. We compare our results with those obtained from global oscillation properties, and discuss the possible sources of uncertainties in asteroseismic stellar modeling where further studies are still needed.Comment: 46 pages, 10 figures, ApJ accepte

    Observation of Magnetic Moments in the Superconducting State of YBa2_2Cu3_3O6.6_{6.6}

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    Neutron Scattering measurements for YBa2_2Cu3_3O6.6_{6.6} have identified small magnetic moments that increase in strength as the temperature is reduced below T∗T^\ast and further increase below TcT_c. An analysis of the data shows the moments are antiferromagnetic between the Cu-O planes with a correlation length of longer than 195 \AA in the aa-bb plane and about 35 \AA along the c-axis. The origin of the moments is unknown, and their properties are discusssed both in terms of Cu spin magnetism and orbital bond currents.Comment: 9 pages, and 4 figure

    Effectiveness of TiN porous templates on the reduction of threading dislocations in GaN overgrowth by organometallic vapor-phase epitaxy

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    We report on the reduction of threading dislocations in GaN overlayers grown by organometallic vapor phase epitaxy on micro-porous TiN networks. These networks were obtained by in situannealing of thin Ti layers deposited in a metalization chamber, on the (0001) face of GaN templates. Observations by transmission electron microscopy indicate dislocation reduction by factors of up to 10 in GaN layers grown on TiN networks compared with the control GaN.X-ray diffraction shows that GaNgrown on the TiN network has a smaller (102) plane peak width (4.6 arcmin) than the control GaN (7.8 arcmin). In low temperature photoluminescence spectra, a narrow excitonic full-width-at-half-maximum of 2.4 meV was obtained, as compared to 3.0 meV for the control GaN, confirming the improved crystalline quality of the overgrown GaN layers

    Effect of n+-GaN subcontact layer on 4H–SiC high-power photoconductive switch

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    High-power photoconductive semiconductor switching devices were fabricated on 4H–SiC. In order to prevent current crowding, reduce the contact resistance, and avoid contact degradation, a highly n-doped GaN subcontact layer was inserted between the contact metal and the high resistivity SiC bulk. This method led to a two orders of magnitude reduction in the on-state resistance and, similarly, the photocurrent efficiency was increased by two orders of magnitude with the GaN subcontact layer following the initial high current operation. Both dry etching and wet etching were used to remove the GaN subcontact layer in the channel area. Wet etching was found to be more suitable than dry etching
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