196,854 research outputs found
Nanopore formation induced by ion-implantation in Ge: optical properties
No full textSelf-ion implantation on bulk Ge induces the formation of nanopores,
and their growth, structure and transport properties have been recently reported
[1]. Semiconductors containing nanopores have gained a renewed interest as
they are able to adsorb and interact with atoms and molecules and can thus be
used in several interesting and emerging applications. In this contribution we
report on the influence of ion implantation and subsequent nanopore formation
on optoelectronic properties of Ge samples. The analyses are carried out by
Surface Photovoltage (SPV) Spectroscopy, a powerful technique to get detailed
information on material optical properties [2]. Different nanoporous (np)
structures have been investigated: crystalline and amorphous np-Ge obtained
by implantation of bulk Ge, as well as crystalline and amorphous np-Ge obtained
by ion implantation of Ge film grown on Si substrates by molecular beam
epitaxy and sputtering. Changes in the SPV spectra as a function of ion
implantation fluence and annealing treatments are discussed on the basis of the
structural properties of the samples. Quantum confinement effects in
nanoporous Ge film have been demonstrated, while a significant SPV
enhancement in np-Ge samples decorated with Au nanoparticles has been
shown. These results can be of major interest for future photovoltaic
applications of thin film solar cells. G Impellizzeri et al Nanotechn 23, 395604
(2012) L Kronik and Y. Shapira, Surf Sci Rep. 37,1 (1999
Effects of One Versus Two Games a Week on Physical and Subjective Scores of Sub-Elite Soccer Players
No full textThe physical-performance profiles of subelite male footballers were monitored during 6 wk of a competitive season. The same squad of players played either 1 (1G, n = 15) or 2 (2G, n = 15) competitive matches per week. On weeks 0, 3, and 6, 48 h postmatch, players completed countermovement jump (CMJ), 10- and 20-m sprints, the Yo-Yo Intermittent Recovery Test (YYIRT), and the Recovery-Stress Questionnaire. Both groups undertook 2 weekly training sessions. The 2G showed after 6 wk lower YYIRT (-11% to 3%, 90% CI -15.8% to -6.8%; P < .001) and CMJ performances (-18.7%, -21.6 to -15.9%; P = .007) and higher 10-m (4.4%, 1.8-6.9%; P = .007) and 20-m sprints values (4.7%, 2.9% to 6.4%; P < .001). No differences were found at 3 wk (.06 < P < .99). No changes over time (.169 < P < .611) and no differences time × group interactions (.370 < P < .550) were found for stress, recovery, and the Stress Recovery Index. In conclusion players' ability to sprint, jump, and perform repeated intense exercise was impaired when playing 2 competitive matches a week over 6 wk
The neuroprotective effects of micronized PEA (PEA-m) formulation on diabetic peripheral neuropathy in mice
No full textDiabetic peripheral neuropathy (DPN) is a complication of diabetes connected with morbidity and mortality. DPN presents deterioration of peripheral nerves with pain, feebleness, and loss of sensation. Particular medications might display their remedial potential by controlling neuroinflammation. Palmitoylethanolamide (PEA) is an autacoid local injury antagonist distinguished for its neuroprotective, analgesic, and anti-inflammatory properties in numerous experimental models of neuroinflammation. Based on these findings, the goal of this work was to better test the neuroprotective effects of a formulation of micronized PEA (PEA-m) and the probable mechanism of action in a mouse model of DPN induced by streptozotocin (STZ) injection. Diabetic and control animals received PEA-m (10 mg/kg) by oral gavage daily starting 2 wk from STZ injection. After 16 wk, the animals were euthanized, and blood, urine, spinal cord, and sciatic nerve tissues were collected. Our results demonstrated that after diabetes induction, PEA-m was able to reduce mechanical, thermal hyperalgesia, and motor alterations as well as reduce mast cell activation and nerve growth factor expression. In addition, PEA-m decreased neural histologic damage, oxidative and nitrosative stress, cytokine release, angiogenesis, and apoptosis. Moreover, spinal microglia activation (IBA-1), phospho-P38 MAPK, and nuclear factor NF-κB inflammatory pathways were also inhibited. The protective effects of PEA-m could be correlated at least in part to peroxisome proliferator-activated receptor-α activation. In summary, we demonstrated that PEA-m represents a new therapeutic strategy for neuroinflammation pain associated with mixed neuropathies.—Impellizzeri, D., Peritore, A. F., Cordaro, M., Gugliandolo, E., Siracusa, R., Crupi, R., D'Amico, R., Fusco, R., Evangelista, M., Cuzzocrea, S., Di Paola, R. The neuroprotective effects of micronized PEA (PEA-m) formulation on diabetic peripheral neuropathy in mice. FASEB J. 33, 11364–11380 (2019). www.fasebj.org
Effects of recreational football performed once a week (1 hour per 12 weeks) on cardiovascular risk factors in middle-aged sedentary men
No full textObjectives: It is well established that there is a strong relationship between physical activity, cardiovascular diseases and mortality. Regular recreational football training can lower blood pressure, heart rate at rest, fat percentage, LDL cholesterol and increase maximal aerobic power (VO2max). This study analyzed the effect of one recreational football training per week on middle-aged men. Design: Randomized controlled trial. Methods: Twenty-four participants (mean ± SDs; age 44.5 ± 4.7 years, weight 81.9 ± 10.4 kg, height 175.0 ± 7.3 cm) were randomized in a football group (FG = 10) and control group (CG = 14). FG performed supervised recreational football training (five-a-side futsal match) on 36 × 18.5 m synthetic indoor and outdoor field, 60 min per week over 12 weeks. Results: After training, VO2max and maximal aerobic speed improved in FG respectively of 4.4% (+1.89 mL O2⋅ kg−1.min−1 , P = 0.002) and 5.9% (P = 0.01). Systolic and mean blood pressure decreased respectively of 2.5% (−3.18 mmHg, P = 0.04) and 2.2% (−2.28 mmHg, P = 0.04) in FG, while diastolic blood pressure did not change (−1.84 mmHg, P = 0.09). Conclusions: Recreational football activity produces health benefits by improving VO2 max and lowering blood pressure parameters in middle-aged men
Effects of low vs moderate dose of recreational football on cardiovascular risk factors
No full textThis study aimed to compare the effectiveness of recreational football performed once (LOW) vs. twice (MOD) a week on cardiovascular risk factors in healthy, sedentary men. Body composition, resting blood pressure, blood lipid profile and maximal oxygen consumption (VO2max) were measured at baseline, after a 12-week control and training period, using an interrupted time series study (study 1, n=18: n=8, LOW and n=10, MOD) nested in a randomised parallel trial (study 2, n=34: n=18 LOW and n=16 MOD). After the intervention in the study 1, LDL-Cholesterol (-12.3 mg•dL-1 [-22.7 to -2.0]) and VO2max (4.5 ml•kg-1•min-1 [1.2 to 7.8 ]) changed in LOW whereas differences were found in weight (-2.1 kg [-3.7 to -0.4]), BMI (-0.7 kg•m-2 [-1.2 to -0.1]), total cholesterol (-22.2 mg•dL-1 [-36.0 to -8.4]), no-HDL-cholesterol (-17.5 mg•dL-1 [-30.5 to -4.5]), LDL-cholesterol (-14.9 mg•dL-1 [-23.6 to -6.2]) and VO2max (5.7 ml•kg-1•min-1 [2.8 to 8.6]) in MOD. Study 2 showed no evidence of differences between groups. Our results therefore, suggest positive health effects of recreational football even when performed at low frequency as it can happen in real context
Quantification of energy expenditure of recreational football
No full textThere is a strong relationship between low physical activity level and cardiovascular diseases (CVD). The popularity of football may be used to promote physical activity and previous evidence has shown it is effective to decrease the risk of CVD. However, the energy expenditure (EE) of recreational football is not well known but it is crucial to develop preventive health programmes.Fifteen sedentary middle-aged male participants were involved (mean +/- SDs; age 43.9 +/- 3.1years, weight 83.0 +/- 13.6kg, height 174.9 +/- 6.8cm). EE was estimated from the heart rate (HR)-VO2 relation during 1-h 5-a-side matches (futsal). Participants covered 3412 +/- 381m in 52 +/- 2min, at an average HR of 85 +/- 2% of maximum HR. Estimated EE during a recreational futsal match was 634 +/- 92 kcal. One futsal recreational match corresponds to about 50% of American College of Sport Medicine recommended physical activity quantity per week. Based on this estimation: once, twice and 3 sessions per week are equivalent to 50% (634 kcal), 100% (1268 kcal) and 150% (1902 kcal), respectively, of EE suggested in international guidelines. This EE estimation may have important implications for designing recreational football training protocols in health programmes and dose response studies
Internal and external training load: 15 years on
No full textExercise is a stressor that induces various psychophysiological responses, which mediate cellular adaptations in many organ systems. To maximize this adaptive response, coaches and scientists need to control the stress applied to the athlete at the individual level. To achieve this, precise control and manipulation of the training load are required. In 2003, the authors introduced a theoretical framework to define and conceptualize the measurable constructs of the training process. They described training load as having 2 measurable components: internal and external load. The aim of this commentary is to extend, clarify, and refine both the theoretical framework and the definitions of internal and external training load to avoid misinterpretation of this concept
Applicability of a change of direction ability field test in soccer assistant referees.
No full textThe aim of this study was to examine the applicability of a test for change of direction ability (10-8-8-10 test, involving line and sideward sprinting, 36 m) in elite-level soccer assistant referees (ARs). One hundred AR of the first-second and third Italian Championships (ARA-B and ARC, n = 50, respectively) performed the 10-8-8-10 on 3 separate occasions. Twenty AR authorities scored test relevance (1-5 scale, from trivial to very large) for logical validity using a questionnaire. Construct validity was examined comparing ARA-B and ARC for the 10-8-8-10 performance. Short-term reliability was assessed testing a random selection of ARs (n = 64) over 3 separate occasions every other day. Performance in the 10-8-8-10 test was assumed as total coverage time using telemetric photocells. Results showed that the 10-8-8-10 test was perceived as possessing from large (n = 4/20) to very-large (n = 16/20) relevance to AR physical match performance. No significant performance difference was found between competitive levels (p = 0.57). Area under the curve (= 0.49; p = 0.87) showed no significant sensitivity of 10-8-8-10 in detecting competitive-level difference. The intraclass correlation coefficient (n = 64) and typical error of measurement (test 2 vs. 3) values were 0.90 (p < 0.0001) and 0.18 seconds, respectively. This study showed that the 10-8-8-10 test possesses logical validity, good reliability, and it is independent of the competitive level. As such, this original investigation represents the first step in the identification and assessment of a valid and reliable AR change of direction test. Given the strength of our findings, governing bodies should look to integrate the 10-8-8-10 test into the fitness test protocols devised for ARs, with scores ≥ 9.67 being considered as a starting point for the empirical validation of minimum selection criteria for elite-level ARs
Oxygen behavior in germanium during melting laser thermal annealing
No full textThe diffusion of oxygen and its interactions with dopants during laser thermal annealing (LTA) in the melting regime is investigated. O is shown to penetrate from the surface and to diffuse during LTA both into germanium un- and also implanted with arsenic or boron. In the latter cases, the diffusion is unaffected by As, whereas it is significantly reduced by B. Accordingly, the electrical activation of As and B are respectively un-and anti-correlated with O. Therefore, it is concluded that O does not interact with As nor in the melt, nor in the solid phase during the cooling transient. On the other hand, the B-O clustering reported in literature to explain the B deactivation during LTA [Impellizzeri et al., J. Appl. Phys. 113(2013) 113505] occurs already in the liquid phase during the regrowth. Thence, the present data provide noteworthy results for the LTA implementation in future complementary metal-oxide devices
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