The impact of sleeping with reduced glycogen stores on immunity and sleep in triathletes.

PURPOSE: We investigated the effects of a 3-week dietary periodization on immunity and sleep in triathletes. METHODS: 21 triathletes were divided into two groups with different nutritional guidelines during a 3-week endurance training program including nine twice a day sessions with lowered (SL group) or maintained (CON group) glycogen availability during the overnight recovery period. In addition to performance tests, sleep was monitored every night. Systemic and mucosal immune parameters as well as the incidence of URTI were monitored every week of the training/nutrition protocol. Two-ways ANOVA and effect sizes were used to examine differences in dependent variables between groups at each time point. RESULTS: The SL group significantly improved 10 km running performance (-1 min 13 s, P < 0.01, d = 0.38), whereas no improvement was recorded in the CON group (-2 s, NS). No significant changes in white blood cells counts, plasma cortisol and IL-6 were recorded over the protocol in both groups. The vitamin D status decreased in similar proportions between groups, whereas salivary IgA decreased in the SL group only (P < 0.05, d = 0.23). The incidence of URTI was not altered in both groups. All participants in both groups went to bed earlier during the training program (SL -20 min, CON -27 min, P < 0.05, d = 0.28). In the SL group, only sleep efficiency slightly decreased by 1.1 % (P < 0.05, d = 0.25) and the fragmentation index tended to increase at the end of the protocol (P = 0.06). CONCLUSION: Sleeping and training the next morning regularly with reduced glycogen availability has minimal effects on selected markers of immunity, the incidence of URTI and sleeping patterns in trained athletes

Kondo Effect in Electromigrated Gold Break Junctions

We present gate-dependent transport measurements of Kondo impurities in bare gold break junctions, generated with high yield using an electromigration process that is actively controlled. Thirty percent of measured devices show zero-bias conductance peaks. Temperature dependence suggests Kondo temperatures \~7K. The peak splitting in magnetic field is consistent with theoretical predictions for g=2, though in many devices the splitting is offset from 2guB by a fixed energy. The Kondo resonances observed here may be due to atomic-scale metallic grains formed during electromigration.Comment: 5 pages, 3 figure

Theory of the Fano Resonance in the STM Tunneling Density of States due to a Single Kondo Impurity

The conduction electron density of states nearby single magnetic impurities, as measured recently by scanning tunneling microscopy (STM), is calculated, taking into account tunneling into conduction electron states only. The Kondo effect induces a narrow Fano resonance in the conduction electron density of states, while scattering off the d-level generates a weakly energy dependent Friedel oscillation. The line shape varies with the distance between STM tip and impurity, in qualitative agreement with experiments, but is very sensitive to details of the band structure. For a Co impurity the experimentally observed width and shift of the Kondo resonance are in accordance with those obtained from a combination of band structure and strongly correlated calculations.Comment: 4 pages, ReVTeX + 4 figures (Encapsulated Postscript), submitted to PR

Crossover from Kondo assisted suppression to co-tunneling enhancement of tunneling magnetoresistance via ferromagnetic nanodots in MgO tunnel barriers

Recently, it has been shown that magnetic tunnel junctions with thin MgO tunnel barriers exhibit extraordinarily high tunneling magnetoresistance (TMR) values at room temperature1, 2. However, the physics of spin dependent tunneling through MgO barriers is only beginning to be unravelled. Using planar magnetic tunnel junctions in which ultra-thin layers of magnetic metals are deposited in the middle of a MgO tunnel barrier here we demonstrate that the TMR is strongly modified when these layers are discontinuous and composed of small pancake shaped nanodots. At low temperatures, in the Coulomb blockade regime, for layers less than ~1 nm thick, the conductance of the junction is increased at low bias consistent with Kondo assisted tunneling. In the same regime we observe a suppression of the TMR. For slightly thicker layers, and correspondingly larger nanodots, the TMR is enhanced at low bias, consistent with co-tunneling.Comment: Nano Letters (in press

Nonequilibrium Transport through a Kondo Dot in a Magnetic Field: Perturbation Theory

Using nonequilibrium perturbation theory, we investigate the nonlinear transport through a quantum dot in the Kondo regime in the presence of a magnetic field. We calculate the leading logarithmic corrections to the local magnetization and the differential conductance, which are characteristic of the Kondo effect out of equilibrium. By solving a quantum Boltzmann equation, we determine the nonequilibrium magnetization on the dot and show that the application of both a finite bias voltage and a magnetic field induces a novel structure of logarithmic corrections not present in equilibrium. These corrections lead to more pronounced features in the conductance, and their form calls for a modification of the perturbative renormalization group.Comment: 16 pages, 7 figure

Consensus Statement Immunonutrition and Exercise.

In this consensus statement on immunonutrition and exercise, a panel of knowledgeable contributors from across the globe provides a consensus of updated science, including the background, the aspects for which a consensus actually exists, the controversies and, when possible, suggested directions for future research

The Kondo Effect in Non-Equilibrium Quantum Dots: Perturbative Renormalization Group

While the properties of the Kondo model in equilibrium are very well understood, much less is known for Kondo systems out of equilibrium. We study the properties of a quantum dot in the Kondo regime, when a large bias voltage V and/or a large magnetic field B is applied. Using the perturbative renormalization group generalized to stationary nonequilibrium situations, we calculate renormalized couplings, keeping their important energy dependence. We show that in a magnetic field the spin occupation of the quantum dot is non-thermal, being controlled by V and B in a complex way to be calculated by solving a quantum Boltzmann equation. We find that the well-known suppression of the Kondo effect at finite V>>T_K (Kondo temperature) is caused by inelastic dephasing processes induced by the current through the dot. We calculate the corresponding decoherence rate, which serves to cut off the RG flow usually well inside the perturbative regime (with possible exceptions). As a consequence, the differential conductance, the local magnetization, the spin relaxation rates and the local spectral function may be calculated for large V,B >> T_K in a controlled way.Comment: 9 pages, invited paper for a special edition of JPSJ "Kondo Effect -- 40 Years after the Discovery", some typos correcte

A new method for the PP-PR hysteresis phenomenon enhancement under exercise conditions

A non-linear relation between PR and PP intervals has been established in a previous work [1] under maximal and graded exercise test as well as under pyramidal ex-ercise where the effort is not released abruptly. This study presents a new method whose aim is to exhibit more clearly the hysteresis behavior of this non-linear relation under graded exercise. After the description of the initial ap-proach, we propose a second one which can provide a bet-ter estimation of the PR intervals. Moreover pooling the results of these two methods leads to an improvement of the estimation accuracy of PR intervals and then the hys-teresis. It is well known that a hysteresis behavior exists at AV node’s level, between the refractory period and the repo-larization period. Besides, the autonomic neural system also acts upon the cardiac activity during an intense ef-fort. Therefore, hysteresis which links the “PR interval vs PP interval ” seems not be explained only at the cellular level; the heart must be viewed in his global context con-sidering the nervous system. 1

Influence of a montmorency cherry juice blend on indices of exercise-induced stress and upper respiratory tract symptoms following marathon running—a pilot investigation

Background: Prolonged exercise, such as marathon running, has been associated with an increase in respiratory mucosal inflammation. The aim of this pilot study was to examine the effects of Montmorency cherry juice on markers of stress, immunity and inflammation following a Marathon. Methods: Twenty recreational Marathon runners consumed either cherry juice (CJ) or placebo (PL) before and after a Marathon race. Markers of mucosal immunity secretory immunoglobulin A (sIgA), immunoglobulin G (IgG), salivary cortisol, inflammation (CRP) and self-reported incidence and severity of upper respiratory tract symptoms (URTS) were measured before and following the race. Results: All variables except secretory IgA and IgG concentrations in saliva showed a significant time effect (P < 0.01). Serum CRP showed a significant interaction and treatment effect (P < 0.01). The CRP increase at 24 and 48 h post-Marathon was lower (P < 0.01) in the CJ group compared to PL group. Mucosal immunity and salivary cortisol showed no interaction effect or treatment effect. The incidence and severity of URTS was significantly greater than baseline at 24 h and 48 h following the race in the PL group and was also greater than the CJ group (P < 0.05). No URTS were reported in the CJ group whereas 50 % of runners in the PL group reported URTS at 24 h and 48 h post-Marathon. Conclusions: This is the first study that provides encouraging evidence of the potential role of Montmorency cherries in reducing the development of URTS post-Marathon possibly caused by exercise-induced hyperventilation trauma, and/or other infectious and non-infectious factors