Landau Level Collapse in Gated Graphene Structures

We describe a new regime of magnetotransport in two dimensional electron systems in the presence of a narrow potential barrier imposed by external gates. In such systems, the Landau level states, confined to the barrier region in strong magnetic fields, undergo a deconfinement transition as the field is lowered. We present transport measurements showing Shubnikov-de Haas (SdH) oscillations which, in the unipolar regime, abruptly disappear when the strength of the magnetic field is reduced below a certain critical value. This behavior is explained by a semiclassical analysis of the transformation of closed cyclotron orbits into open, deconfined trajectories. Comparison to SdH-type resonances in the local density of states is presented.Comment: 4 pages, 2 figure

The Acute and Chronic Effect of Korea Ginseng Supplement on Exercise Performance, Cognitive Function, and Fatigue Recovery

The purpose of this study was to determine the acute and chronic effects of Korean ginseng supplements on exercise performance, cognitive function, and fatigue recovery. The study used double-blind, placebo-controlled, crossover design. Twelve healthy adult males (age = 31 ± 6.86 yrs) were randomly assigned to either KGD or placebo trials. All subjects conducted the exercise consisted with 30 minutes cycling at 70-75% of VO2 max followed by 16 km time trial with 30 minutes resting periods. All subjects were tested for muscular power, strength, endurance, cognitive function, and fatigue. The subjects took KGD (280 ml containing 5.88 mg of ginsenosides) or placebo 90 mins before exercise trials and following 7 days. The blood sample was drawn for IL-6, myoglobin, and total antioxidant capacity immediately after time trial, as well as 2, 24, 48, and 72 hours. After 2 weeks of wash-out period, the subjects were crossed over into the opposite trial and performed the same test. Repeated measures ANOVAs were used to examine the effect of acute and chronic intake of ginseng on exercise performance and blood variables. An alpha of .05 was used, and the Greenhouse-Geisser (G-G) adjusted F and degrees of freedom were reported. In a placebo trial, peak power and mean power levels were significantly decreased across time, F (1.47, 13.24) = 4.63, G-G p = .039, h2p = .340 and F (1.46, 13.13) = 5.31, G-G p = .028, h2p = .371 while no differences were found in a ginseng trial. In a placebo trial, average reaction time (ART) was significantly increased across time, F (1.29, 11.63) = 10.81, G-G p = .005, h2p = .546, but in a ginseng trial, no difference in ART was found across time, F (1.54, 13.86) = 4.02, G-G p = .051, h2p = .309. There was a significant increase in TAC across time in a ginseng trial, F (1.42, 11.37) = 5.07, G-G p = .035, h2p = .388 while no difference was found in a placebo trial. No significant differences were found in other variables from placebo and ginseng trails. The 7 days of KRG supplementation significantly reduced the serum myoglobin concentration across time in the KGD trial, F (1.88, 13.17) = 5.18, G-G p = .023, while no difference was found in the placebo trial, F (2.21, 17.66) = .88, G-G p = .443. No significant differences were observed in serum total antioxidant activity and IL-6 between KGD and placebo trials. The study shows that Korean ginseng supplement before stating the exercise improve anaerobic capacity, cognitive function in particular psychomotor vigilance task, and fatigue recovery during cycling exercise. And 7 days of Korean ginseng supplement reduces muscle damage and fatigue after cycling exercise

GLP-1 receptor agonists in diabetic kidney disease: current evidence and future directions

With the emergence of various classes of blood glucose-lowering agents, choosing the appropriate drug for each patient is emphasized in diabetes management. Among incretin-based drugs, glucagon-like peptide 1 (GLP-1) receptor agonists are a promising therapeutic option for patients with diabetic kidney disease (DKD). Several cardiovascular outcome trials have demonstrated that GLP-1 receptor agonists have beneficial effects on cardiorenal outcomes beyond their blood glucose-lowering effects in patients with type 2 diabetes mellitus (T2DM). The renal protective effects of GLP-1 receptor agonists likely result from their direct actions on the kidney, in addition to their indirect actions that improve conventional risk factors for DKD, such as reducing blood glucose levels, blood pressure, and body weight. Inhibition of oxidative stress and inflammation and induction of natriuresis are major renoprotective mechanisms of GLP-1 analogues. Early evidence from the development of dual and triple combination agents suggests that GLP-1 receptor agonists will probably become popular treatment options for patients with T2DM

Tetraarsenic Hexoxide Induces Beclin-1-Induced Autophagic Cell Death as well as Caspase-Dependent Apoptosis in U937 Human Leukemic Cells

Tetraarsenic hexaoxide (As4O6) has been used in Korean folk remedy for the treatment of cancer since the late 1980s, and arsenic trioxide (As2O3) is currently used as a chemotherapeutic agent. However, evidence suggests that As4O6-induced cell death pathway was different from that of As2O3. Besides, the anticancer effects and mechanisms of As4O6 are not fully understood. Therefore, we investigated the anticancer activities of As4O6 on apoptosis and autophagy in U937 human leukemic cells. The growth of U937 cells was inhibited by As4O6 treatment in a dose- and a time-dependent manner, and IC50 for As4O6 was less than 2 μM. As4O6 induced caspase-dependent apoptosis and Beclin-1-induced autophagy, both of which were significantly attenuated by Bcl-2 augmentation and N-acetylcysteine (NAC) treatment. This study suggests that As4O6 should induce Beclin-1-induced autophagic cell death as well as caspase-dependent apoptosis and that it might be a promising agent for the treatment of leukemia

Association of circulating omentin-1 level with arterial stiffness and carotid plaque in type 2 diabetes

<p>Abstract</p> <p>Background</p> <p>Adipokines contribute directly to the atherosclerotic process, connecting metabolic disorders such as obesity and diabetes to cardiovascular disease. Omentin-1 is a recently discovered novel adipokine, so data about the relationship of this adipokine to vascular health in type 2 diabetes is limited.</p> <p>Methods</p> <p>We enrolled 60 people with type 2 diabetes, with or without carotid plaque, and 30 participants with normal glucose tolerance. We measured serum omentin-1, high-sensitivity C-reactive protein (hsCRP) levels, and the homeostasis model assessment of insulin resistance (HOMA-IR), as well as other cardiovascular risk factors. Vascular health was assessed by brachial ankle pulse wave velocity (baPWV) and carotid intima-media thickness (IMT).</p> <p>Results</p> <p>Serum omentin-1 levels were significantly decreased in type 2 diabetes patients compared to normal glucose controls and was further reduced in type 2 diabetes patients with carotid plaque compared to those without carotid plaque. Multiple stepwise regression analysis showed that age, systolic blood pressure, history of use of statins, angiotensin receptor blockers or angiotensin-converting enzyme inhibitors, and serum omentin-1 level were independent factors determining baPWV in people with type 2 diabetes (<it>r</it>²= 0.637). Furthermore, in multivariate logistic regression analysis, circulating omentin-1 level was an independent decisive factor for the presence of carotid plaque in type 2 diabetes patients, even after adjusting for age, gender, body mass index, systolic blood pressure, fasting blood glucose, low density lipoprotein cholesterol, and history of smoking and medication (odds ratio, 0.621; 95% confidence interval, 0.420-0.919; <it>P </it>= 0.017).</p> <p>Conclusions</p> <p>Circulating omentin-1 level was independently correlated with arterial stiffness and carotid plaque in type 2 diabetes, even after adjusting for other cardiovascular risk factors and detailed medication history.</p