846 research outputs found
Exploring Low Internal Reorganization Energies for Silicene Nanoclusters
High-performance materials rely on small reorganization energies to
facilitate both charge separation and charge transport. Here, we performed DFT
calculations to predict small reorganization energies of rectangular silicene
nanoclusters with hydrogen-passivated edges denoted by H-SiNC. We observe that
across all geometries, H-SiNCs feature large electron affinities and highly
stabilized anionic states, indicating their potential as n-type materials. Our
findings suggest that fine-tuning the size of H-SiNCs along the zigzag and
armchair directions may permit the design of novel n-type electronic materials
and spinctronics devices that incorporate both high electron affinities and
very low internal reorganization energies.Comment: 25 pages, 6 figure
Proprietary Milk Protein Concentrate Reduces Joint Discomfort While Improving Exercise Performance in Non-Osteoarthritic Individuals
Milk and dairy products are known to contain various bioactives with potential anti-inflammatory and immune modulating effects. Previous research has indicated that milk produced from hyperimmunized cows provided meaningful health benefits to individuals suffering from varying degrees of osteoarthritis and rheumatoid arthritis. PURPOSE: To examine the impact of a proprietary milk protein concentrate on joint discomfort and physical function, exercise performance, quality of life and various measures of affect. METHODS: Non-osteoarthritic men (42.5 ± 8.9 years, 176.7 ± 6.7 cm, 89.9 ± 11.5 kg, 28.8 ± 3.5 kg/m2, n = 30) and women (46.4 ± 9.6 years, 163.1 ± 8.2 cm, 72.2 ± 13.1 kg, 27.2 ± 5.3 kg/m2, n = 28) with mild to moderate knee pain during physical activity were randomized in a double-blind, placebo-controlled fashion to consume daily either a placebo (PLA) or a proprietary milk protein concentrate (MP) for a period of 8 weeks. Participants completed a functional capacity test pre and post-supplementation and completed visual analog scales (VAS), a 6-min walking test, WOMAC and profile of mood states (POMS) to assess changes in joint health, discomfort, physical function, exercise performance and affect. Mixed factorial ANOVA was used for all statistical analysis and significance was set a priori at p ≤ 0.05. RESULTS: Distance covered in the 6-min walking significantly improved 9% in MP versus 2% in PLA (mean difference: 110 ± 43 m, p = 0.012) in addition to 11 WOMAC components and 5 VAS reflective of MP improving joint health, discomfort and joint stability (all p \u3c 0.05 vs. PLA). Additionally, MP also improved overall perceptions of neck and back health compared to PLA. Serum and whole blood indicators of clinical safety remained within normal ranges throughout the study. CONCLUSIONS: In comparison to placebo, daily doses of proprietary milk protein concentrate yielded improvements in several components of the WOMAC, multiple visual analog scales indicative of joint health and stability, discomfort and pain, as well as significant improvements in distance covered during a 6-min walking test. Supplementation was well tolerated with no significant changes in whole-blood or serum markers of clinical safety
Precipitation Process in Fe-Ni-Al-based Alloys
This chapter covers first the precipitation and coarsening processes in Fe-Ni-Al alloys aged artificially at high temperatures, as well as their effect on the mechanical properties. These results show the precipitation evolution, morphology of precipitates, coarsening kinetics and mechanical properties such as hardness. Additionally, the effect of alloying elements such as copper and chromium is also studied on the precipitation and coarsening processes. The main results of this section are concerning on the coarsening kinetics and its effect on hardness. Besides, the diffusion couple method is employed to study the precipitation and coarsening process in different Fe-Ni-Al alloy compositions, as well as its effect on the hardness. All the above aspects of precipitation and coarsening are also supported with Thermo-Calc calculations
Soldabilidad en aceros inoxidables y aceros disimiles
La necesidad de unir aceros disímiles mediante procesos de soldadura por arco eléctrico es una práctica muy poco común, pero que, en algunos casos, se hace necesario por la complejidad de algunos equipos y máquinas (como calderas recuperadoras de calor, turbinas, intercambiadores de calor, etc.) requeridos en la industria. Las uniones más usuales son entre aceros de baja aleación o no aleados, con aceros de alta aleación (como los aceros inoxidables austeníticos). Lo anterior requiere que se elijan cuidadosamente los procesos, los metales de aporte y los métodos de aplicación de las soldaduras para que esta quede lo más cercana posible a la naturaleza de los aceros a unir. Uno de los métodos que genera mejores resultados en este tipo de uniones, es la utilización del diagrama de Schaeffler [1]. Mediante el estudio y el manejo de este diagrama se puede predecir la estructura del metal de soldadura obtenido en la unión de aceros inoxidables disímiles, o de aceros inoxidables con aceros al carbono, con o sin aleación, partiendo del níquel equivalente tanto de los materiales base como de los materiales de aporte
Soldabilidad en aceros inoxidables y aceros disimiles
La necesidad de unir aceros disímiles mediante procesos de soldadura por arco eléctrico es una práctica muy poco común, pero que, en algunos casos, se hace necesario por la complejidad de algunos equipos y máquinas (como calderas recuperadoras de calor, turbinas, intercambiadores de calor, etc.) requeridos en la industria. Las uniones más usuales son entre aceros de baja aleación o no aleados, con aceros de alta aleación (como los aceros inoxidables austeníticos). Lo anterior requiere que se elijan cuidadosamente los procesos, los metales de aporte y los métodos de aplicación de las soldaduras para que esta quede lo más cercana posible a la naturaleza de los aceros a unir. Uno de los métodos que genera mejores resultados en este tipo de uniones, es la utilización del diagrama de Schaeffler [1]. Mediante el estudio y el manejo de este diagrama se puede predecir la estructura del metal de soldadura obtenido en la unión de aceros inoxidables disímiles, o de aceros inoxidables con aceros al carbono, con o sin aleación, partiendo del níquel equivalente tanto de los materiales base como de los materiales de aporte
Effects of an Aqueous Extract of Withania somnifera on Strength Training Adaptations and Recovery: The STAR Trial
Withania somnifera (Ashwagandha) is an Ayurvedic herb categorized as having “rasayana” (rejuvenator), longevity, and revitalizing properties. Sensoril® is a standardized aqueous extract of the roots and leaves of Withania somnifera. Purpose: To examine the impact of Sensoril® supplementation on strength training adaptations. Methods: Recreationally active men (26.5 ± 6.4 years, 181 ± 6.8 cm, 86.9 ± 12.5 kg, 24.5 ± 6.6% fat) were randomized in a double-blind fashion to placebo (PLA, n = 19) or 500 mg/d Sensoril® (S500, n = 19). Body composition (DEXA), muscular strength, power, and endurance, 7.5 km cycling time trial, and clinical blood chemistries were measured at baseline and after 12 weeks of supplementation and training. Subjects were required to maintain their normal dietary habits and to follow a specific, progressive overload resistance-training program (4-day/week, upper body/lower body split). 2 × 2 mixed factorial ANOVA was used for analysis and statistical significance was set a priori at p ≤ 0.05. Results: Gains in 1-RM squat (S500: +19.1 ± 13.0 kg vs. PLA +10.0 ± 6.2 kg, p = 0.009) and bench press (S500: +12.8 ± 8.2 kg vs. PLA: +8.0 ± 6.0 kg, p = 0.048) were significantly greater in S500. Changes in DEXA-derived android/gynoid ratio (S500: +0.0 ± 0.14 vs. PLA: +0.09 ± 0.1, p = 0.03) also favored S500. No other between-group differences were found for body composition, visual analog scales for recovery and affect, or systemic hemodynamics, however, only the S500 group experienced statistically significant improvements in average squat power, peak bench press power, 7.5 km time trial performance, and perceived recovery scores. Clinical chemistry analysis indicated a slight polycythemia effect in PLA, with no other statistical or clinically relevant changes being noted. Conclusions: A 500 mg dose of an aqueous extract of Ashwagandha improves upper and lower-body strength, supports a favorable distribution of body mass, and was well tolerated clinically in recreationally active men over a 12-week resistance training and supplementation period
Effects of a dietary supplement on golf drive distance and functional indices of golf performance
Background
Limited research exists examining the impact of nutrition on golfing performance. This study’s purpose was to determine the impact of daily supplementation with an over-the-counter dietary supplement on golf performance. Methods
Healthy men (30.3 ± 6.9 y, 183.1 ± 5.6 cm, 86.7 ± 11.9 kg), with a 5–15 handicap were assigned in a double-blind, placebo-controlled manner to ingest for 30 days either a placebo (PLA, n = 13) or a dietary supplement containing creatine monohydrate, coffea arabica fruit extract, calcium fructoborate and vitamin D (Strong Drive™, SD, n = 14). Subjects ingested two daily doses for the first two weeks and one daily dose for the remaining two weeks. Participants followed their normal dietary habits and did not change their physical activity patterns. Two identical testing sessions in a pre/post fashion were completed consisting of a fasting blood sample, anthropometric measurements, 1-RM bench press, upper body power and golf swing performance using their driver and 7-iron. Data were analyzed using two-way mixed factorial ANOVAs and ANCOVA when baseline differences were present. Statistical significance was established a priori at p ≤ 0.05. Results
ANCOVA revealed significantly greater (post-test) best drive distance (p = 0.04) for SD (+5.0% [+13.6 yards], ES = 0.75) as well as a tendency (p = 0.07) for average drive distance to increase (+8.4% [+19.6 yards], ES = 0.65), while no such changes were found with PLA (−0.5% [−1.2 yards], ES = 0.04 and +1.3% [+2.8 yards], ES = 0.08, respectively). Both groups experienced significant increases in body mass and 1-RM bench press (p \u3c 0.001). No other significant group × time interactions were found. For the SD group only, within-group analysis confirmed significant improvements in set 1 average (+8.9%, p = 0.001) and peak velocity (+6.8%, p \u3c =0.01). No changes were noted for reported adverse events, pain inventories, quality of life or any measured blood parameter. Conclusions
SD supplementation for 30 days significantly improved best drive distance more than placebo. Supplementation was well tolerated and did not result in any clinically significant changes in markers of health or adverse events/side effect profiles
Eight weeks of supplementation with a multi-ingredient weight loss product enhances body composition, reduces hip and waist girth, and increases energy levels in overweight men and women
Background: Numerous natural products are marketed and sold claiming to decrease body weight and fat, but few undergo finished product-specific research demonstrating their safety and efficacy.
Objective: To determine the safety and efficacy of a multi-ingredient supplement containing primarily raspberry ketone, caffeine, capsaicin, garlic, ginger and Citrus aurantium (Prograde Metabolism™ [METABO]) as an adjunct to an eight-week weight loss program.
Methods: Using a randomized, placebo-controlled, double-blind design, 70 obese but otherwise healthy subjects were randomly assigned to METABO or a placebo and underwent 8 weeks of daily supplementation, a calorie restricted diet, and exercise training. Subjects were tested for changes in body composition, serum adipocytokines (adiponectin, resistin, leptin, TNF-α, IL-6) and markers of health including heart rate and blood pressure.
Results: Of the 45 subjects who completed the study, significant differences were observed in: body weight (METABO -2.0% vs. placebo -0.5%, P < 0.01), fat mass (METABO -7.8 vs. placebo -2.8%, P < 0.001), lean mass (METABO +3.4% vs. placebo +0.8%, P < 0.03), waist girth (METABO -2.0% vs. placebo -0.2%, P < 0.0007), hip girth (METABO -1.7% vs. placebo -0.4%, P < 0.003), and energy levels per anchored visual analogue scale (VAS) (METABO +29.3% vs. placebo +5.1%, P < 0.04). During the first 4 weeks, effects/trends for maintaining elevated serum leptin (P < 0.03) and decreased serum resistin (P < 0.08) in the METABO group vs. placebo were also observed. No changes in systemic hemodynamics, clinical blood chemistries, adverse events, or dietary intake were noted between groups.
Conclusions: METABO administration is a safe and effective adjunct to an eight-week diet and exercise weight loss program by augmenting improvements in body composition, waist and hip girth. Adherence to the eight-week weight loss program also led to beneficial changes in body fat in placebo. Ongoing studies to confirm these results and clarify the mechanisms (i.e., biochemical and neuroendocrine mediators) by which METABO exerts the observed salutary effects are being conducted.
Keywords: Dietary supplement; Raspberry ketone; Adipokine; Body composition; Fat loss; Capsaici
Endurecimiento por precipitación en aleaciones al-4%cu-0.5%mg modificadas con ag
El estudio del endurecimiento por precipitación en la aleación Al-4%Cu- 0.5%Mg con adiciones de 0.5-4%Ag se realizó mediante microscopía electrónica de transmisión (MET) y microdureza Vickers. Las aleaciones fueron homogeneizadas a 525°C durante 7 días y templadas. Los tratamientos de precipitación se realizaron a 150, 200 y 250°C por diferentes tiempos. La adición de hasta 3%Ag promueve un aumento en dureza para todos los tratamientos de envejecido. Adicionalmente, los resultados muestran que la coexistencia de las fases θ’ y Ω son las responsables de promover el aumento en dureza. Por otra parte, los análisis de MET confirman que la fase Ω tiene una estructura fcc, es coherente con la matriz, y su morfología es hexagonal con intercaras alineadas en las direcciones [311]α, [022]α y [111]α. Finalmente, la disminución en la dureza de las aleaciones se atribuye a la desaparición de la fase θ’ y al engrosamiento de la fase Ω
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