The influence of hydration on anaerobic performance: a review

This review examines the influence of dehydration on muscular strength and endurance and on single and repeated anaerobic sprint bouts. Describing hydration effects on anaerobic performance is difficult because various exercise modes are dominated by anaerobic energy pathways, but still contain inherent physiological differences. The critical level of water deficit (approximately 3-4%; mode dependent) affecting anaerobic performance is larger than the deficit (approximately 2%) impairing endurance performance. A critical performance-duration component (> 30 s) may also exist. Moderate dehydration (approximately 3% body weight; precise threshold depends on work/recovery ratio) impairs repeated anaerobic bouts, which place an increased demand on aerobic metabolism. Interactions between dehydration level, dehydration mode, testing mode, performance duration, and work/recovery ratio during repeated bouts make the dehydration threshold influencing anaerobic performance mode dependent.     

The programmers’ collective: fostering participatory culture by making music videos in a high school Scratch coding workshop

We highlight ways to support interest-driven creation of digital media in Scratch, a visual-based programming language and community, within a high school programming workshop. We describe a collaborative approach, the programmers’ collective, that builds on social models found in do-it-yourself and open source communities, but with scaffolding structures that support students’ learning. We analyze the work of a class of high school student collectives engaged in programming music videos as part of a collaborative challenge in the online Scratch community. Our multi-level analysis focused on students’ learning specific programming concepts, effects of collaborative and task design on learning, and their personal reflections on collaboration and media creation. We address how these overlapping collaborative experiences point to the value of “nested collectives,” or multiple levels of designed-for collaboration. We also highlight a needed shift from a focus on computation to computational participation, highlighting the innately social aspects of media creation.     

Effect of Resveratrol and Nicotine on PON1 Gene Expression: In Vitro Study

Dietary and lifestyle factors have been shown to have a profound effect on paraoxonase-1 (PON1) activity. Cigarette smoke has been shown to inhibit its mass and activity where as resveratrol has been shown to enhance it. We exposed hepatoma derived cell line (HepG2) to resveratrol and nicotine in varying doses and measured PON1 enzymatic activity and PON1 gene expression. In addition, total protein content of HepG2 cells was also measured. Resveratrol in a dose of 15 μmol/l or above significantly increased the PON1 enzyme activity (p > 0.001) where as nicotine in a dose of 1 μmol/l or higher significantly reduced it (p < 0.05). The resveratrol in this dose also enhanced the PON1 gene expression whereas nicotine decreased it as compared to controls. However, the protein conent of cells was not changed suggesting that they were not cytotoxic in the doses used. Till date the antioxidant vitamins have shown disappointing results against LDL oxidation and cardiovascular protection. However, the effect of resveratrol on PON1 gene expression and activity was significant, suggesting increase in PON1 activity and enhanced gene expression may be its alternative mechanism for offering protection against cardiovascular disease and may be an potential pharmacological agent which can be used for this.     

Classroom as Real World: Propositions for a pedagogy of difference

The article develops a proposal for learning from the differences that can be present in the milieu of postgraduate programmes that are based on a participative design. Drawing on illustrations of students' and tutors' experience of difference, the idea of 'classroom as real world' is offered as the basis of understanding differences and responses to them which could be applied in the wider, and arguably more significant, social context. The authors also explore tensions which tutors are likely to have to engage with if incorporating a pedagogy of difference into their practice. These tensions are between tendencies to conformity or fragmentation, and between participative ideals and incipient hierarchy, not least as implicated in their role.     

Effect of methionine and vitamin C supplementation on pulmonary glutathione-s-transferase and glutathione levels in ageing rats

Glutathione-5-transferase (GST) and glutathione (GSH) levels were estimated in the lungs of 3 and 30 months old rats. GST activity was found to be significantly reduced in the old rats (30 months age) compared to the young rats (3 months age). In old rats, with methionine supplementation GST activity was increased whereas with vitamin C supplementation GSH levels were increased. The data show that the supplementation of methionine as well as of vitamin C have beneficial effect on the scavenging system and protect lungs against the free radical damage during ageing.     

Variations in cadmium and nitrate co-accumulation among water spinach genotypes and implications for screening safe genotypes for human consumption

Vegetables are important constituents of the human diet. Heavy metals and nitrate are among the major contaminants of vegetables. Consumption of vegetables and fruits with accumulated heavy metals and nitrate has the potential to damage different body organs leading to unwanted effects. Breeding vegetables with low heavy metal and nitrate contaminants is a cost-effective approach. We investigated 38 water spinach genotypes for low Cd and nitrate co-accumulation. Four genotypes, i.e. JXDY, GZQL, XGDB, and B888, were found to have low co-accumulation of Cd (<0.71 mg/kg dry weight) and nitrate (<3100 mg/kg fresh weight) in the edible parts when grown in soils with moderate contamination of both Cd (1.10 mg/kg) and nitrate (235.2 mg/kg). These genotypes should be appropriate with minimized risk to humans who consume them. The Cd levels in the edible parts of water spinach were positively correlated with the concentration of Pb or Zn, but Cd, Pb, or Zn was negatively correlated with P concentration. These results indicate that these three heavy metals may be absorbed into the plant in similar proportions or in combination, minimizing the influx to aerial parts. Increasing P fertilizer application rates appears to prevent heavy metal and nitrate translocation to shoot tissues and the edible parts of water spinach on co-contaminated soils.     

Glial Cells: The other cells of the nervous system

Theodor Schwann, the German physiologist who first propounded the cell theory with M Schieiden, had diverse interests. He was not only the first to isolate the enzyme pepsin, but also investigated muscle contraction and nerve structure. In the mid nineteenth century Schwann discovered that a sheath made up of myelin covered the axons of neurons in the peripheral nervous system (PNS). The cells that form the myelin are today called Schwann cells after him. Today, we know that the Schwann cells not only form the myelin sheath around neurons, but also regulate several neuronal functions and are an indispensable part of the PNS.