Effect of Graphene Oxide Nanosheets on Physical Properties of Ultra-High-Performance Concrete with High Volume Supplementary Cementitious Materials.

Nanomaterials have been increasingly employed for improving the mechanical properties and durability of ultra-high-performance concrete (UHPC) with high volume supplementary cementitious materials (SCMs). Recently, graphene oxide (GO) nanosheets have appeared as one of the most promising nanomaterials for enhancing the properties of cementitious composites. To date, a majority of studies have concentrated on cement pastes and mortars with fewer investigations on normal concrete, ultra-high strength concrete, and ultra-high-performance cement-based composites with a high volume of cement content. The studies of UHPC with high volume SCMs have not yet been widely investigated. This paper presents an experimental investigation into the mini slump flow and physical properties of such a UHPC containing GO nanosheets at additions from 0.00 to 0.05% by weight of cement and a water-cement ratio of 0.16. The study demonstrates that the mini slump flow gradually decreases with increasing GO nanosheet content. The results also confirm that the optimal content of GO nanosheets under standard curing and under steam curing is 0.02% and 0.04%, respectively, and the corresponding compressive and flexural strengths are significantly improved, establishing a fundamental step toward developing a cost-effective and environmentally friendly UHPC for more sustainable infrastructure.

Night time resistance exercise alters muscular IL-6-related protein signaling, but not muscle growth after 10 weeks of resistance training in male rats.

The present study investigated the time-of-day effects on acute response and chronic adaptations to resistance exercise (RE) in rat skeletal muscle. Male rats were divided into Early and Late training groups and performed climbing RE during the first or last hour of the active (dark) period, respectively. The first experiment measured muscle mass and strength after a 10-week climbing training program. The second experiment examined inflammatory signaling response and satellite cell (SC) numbers following an acute bout of RE. The results showed no significant differences between rats training at early and late active periods in relative muscle weight (muscle-to-weight ratio), cross sectional area (CSA) and strength. The acute study observed increased STAT1 phosphorylation, oxidative stress (2-thiobarbituric acid reacting substances, TBARS), SCs (Pax7+), neutrophils (His48+) and macrophages (CD68+), and decreased interleukin 6 (IL-6) protein expression of skeletal muscle relative to non-exercise control after an acute bout of RE. Interestingly, higher plasma IL-6 and STAT3 phosphorylation response was observed in the late training group when compared to the early training group after an acute bout of RE. The results of this study suggest that animals can adapt to resistance training at different time-of-day, by modulating inflammatory signaling of skeletal muscle.

Physical Properties of Concrete Containing Graphene Oxide Nanosheets.

Concrete made from ordinary Portland cement is one of the most widely used construction materials due to its excellent compressive strength. However, concrete lacks ductility resulting in low tensile strength and flexural strength, and poor resistance to crack formation. Studies have demonstrated that the addition of graphene oxide (GO) nanosheet can effectively enhance the compressive and flexural properties of ordinary Portland cement paste, confirming GO nanosheet as an excellent candidate for using as nano-reinforcement in cement-based composites. To date, the majority of studies have focused on cement pastes and mortars. Only limited investigations into concretes incorporating GO nanosheets have been reported. This paper presents an experimental investigation on the slump and physical properties of concrete reinforced with GO nanosheets at additions from 0.00% to 0.08% by weight of cement and a water-cement ratio of 0.5. The study demonstrates that the addition of GO nanosheets improves the compressive strength, flexural strength, and split tensile strength of concrete, whereas the slump of concrete decreases with increasing GO nanosheet content. The results also demonstrate that 0.03% by weight of cement is the optimum value of GO nanosheet dosage for improving the split tensile strength of concrete.

Protein supplementation enhances cerebral oxygenation during exercise in elite basketball players.

OBJECTIVE: The aim of the present study was to examine cerebral oxygenation during high-intensity exercise in elite basketball players who consumed supplements with different whey protein contents after a short postexercise recovery to determine whether changing whey protein content in carbohydrate-based supplementation influences cerebral hemodynamic response when the supplement was consumed during a 2-h recovery after a 1-h exercise challenge. METHODS: This was a randomized, counterbalanced crossover study. Fifteen Division 1 collegiate basketball players (18-20 y) consumed 6.25 kcal/kg of either high-protein (36% protein in total calorie) or an isocaloric low-protein (12% protein in total calorie) control supplement in a carbohydrate-based drink immediately after a 1-h cycling (70% of maximal oxygen consumption [VO2max]). After a 2-h rest, the athletes were challenged on a cycloergometer at 80% VO2max. Blood perfusion (total hemoglobin) and oxygen saturation of frontal brain were continuously measured by near-infrared spectroscopy during the cycling. RESULTS: Before the cycloergometer test, high-protein supplementation increased peak insulin response and lowered glucose increases during the recovery compared with the low-protein trial. High-protein supplementation enhanced increases in cerebral oxygen saturation (P < 0.01) and attenuated increases in cerebral blood perfusion (total hemoglobin; P < 0.01) during the cycloergometer exercise; and resulted in a 16% longer cycling time (from 474 ± 49 s to 553 ± 78 s, P < 0.05), compared with the low-protein trial. CONCLUSION: Enhanced fatigue recovery after consumption of a high-protein supplement is associated with enhanced cerebral oxygenation against exercise challenge, which spares brain blood demand for periphery.

Mammalian Metallothionein-2A and Oxidative Stress.

Mammalian metallothionein-2A (MT2A) has received considerable attention in recent years due to its crucial pathophysiological role in anti-oxidant, anti-apoptosis, detoxification and anti-inflammation. For many years, most studies evaluating the effects of MT2A have focused on reactive oxygen species (ROS), as second messengers that lead to oxidative stress injury of cells and tissues. Recent studies have highlighted that oxidative stress could activate mitogen-activated protein kinases (MAPKs), and MT2A, as a mediator of MAPKs, to regulate the pathogenesis of various diseases. However, the molecule mechanism of MT2A remains elusive. A deeper understanding of the functional, biochemical and molecular characteristics of MT2A would be identified, in order to bring new opportunities for oxidative stress therapy.