We report an electron transport study of lithographically fabricated graphene nanoribbons (GNRs) of various widths and lengths. At the charge neutrality point, a length-independent transport gap forms whose size is inversely proportional to the GNR width. In this gap, electrons are localized, and charge transport exhibits a transition between thermally activated behavior at higher temperatures ...

Glutamate in unusual places lutamate has a critical physiological function unrelated to its job as a neurotransmitter, according to results from M.M. Reddy and Paul Quinton (University of California, San Diego, CA). The duo find that glutamate activates an epithelial ion channel that is mutated in patients with cystic fibrosis. Cystic fibrosis is caused by mutations in the CFTR anion channel, w...

Glutamate in unusual places lutamate has a critical physiological function unrelated to its job as a neurotransmitter, according to results from M.M. Reddy and Paul Quinton (University of California, San Diego, CA). The duo find that glutamate activates an epithelial ion channel that is mutated in patients with cystic fibrosis. Cystic fibrosis is caused by mutations in the CFTR anion channel, w...

Mitochondrial ion transport, oxidative phosphorylation, redox balance, and physical integrity are key factors in tissue survival following potentially damaging conditions such as ischemia/reperfusion. Recent research has demonstrated that pharmacologically activated inner mitochondrial membrane ATP-sensitive K+ channels (mitoK(ATP)) are strongly cardioprotective under these conditions. Furtherm...

Glutamate in unusual places lutamate has a critical physiological function unrelated to its job as a neurotransmitter, according to results from M.M. Reddy and Paul Quinton (University of California, San Diego, CA). The duo find that glutamate activates an epithelial ion channel that is mutated in patients with cystic fibrosis. Cystic fibrosis is caused by mutations in the CFTR anion channel, w...

Synaptic plasma membranes isolated from rat brain contain a calmodulin-activated Ca2+ pump. It has been purified 80- to 160-fold by solubilization with Triton X-100 and affinity chromatography on a calmodulin-Sepharose 4B column. After reconstitution into phospholipid vesicles, the affinity-purified pump efficiently catalyzed ATP dependent Ca2+ transport, which was activated 7- to 9-fold by cal...

Passive K+ transport in human erythrocytes (defined as ouabain-insensitive transport) was inhibited 70% by replacement of Cl- by several permeant monovalent anions. The Vmax of Cl--dependent K+ influx was 1.14 mmol . liter-1, hr-1; its apparent Km for K+ was 4.7 mM. There was a much smaller component of Na+ influx dependent on Cl- (Vmax, 0.23 mmol . liter-1 . hr-1). Furosemide and other inhibit...

Frog sympathetic ganglion neurons exhibit a novel Ca2+ uptake mechanism, release-activated calcium transport or RACT, which is manifest in both cytosolic and store [Ca2+] signals as greatly accelerated Ca2+ uptake after Ca2+ release from internal stores. RACT is activated by Ca2+ release but not by Ca2+ entry and serves to selectively refill Ca2+ stores after release. RACT lowers cytosolic [Ca2...

Numerical calculations of anisotropic hopping transport based on the resistor network model are presented. Conductivity is shown to follow the stretched exponential dependence on temperature with exponents increasing from 14 to 1 as the wave functions become anisotropic and their localization length in the direction of charge transport decreases. For sufficiently strong anisotropy, this results...

The AMP-activated protein kinase (AMPK) is an energy-sensing enzyme that is activated by acute increases in the cellular [AMP]/[ATP] ratio. In skeletal and/or cardiac muscle, AMPK activity is increased by stimuli such as exercise, hypoxia, ischemia, and osmotic stress. There are many lines of evidence that increasing AMPK activity in skeletal muscle results in increased rates of glucose transpo...