Firing rate analysis using decompostion-enhanced spike triggered averaging in the quadriceps femoris

Electromyographic signals detected from the quadriceps femoris during various constant force contractions were decomposed to identify individual motor unit discharges and mean firing rates (FRs). Subject and group mean FRs were calculated for each force level. Mean FR values and FR variability increased with force. Individual, subject, and group mean FRs showed slight increases until 30% of maximum voluntary contraction and larger increases thereafter. Findings are discussed in relation to motor unit recruitment, frequency modulation, and fatigue.     

Relationship between ApoE, MRI findings, and cognitive function in the Cardiovascular Health Study

BACKGROUND AND PURPOSE: We determined the relationship between apolipoprotein (Apo)E, MRI, and low cognitive scores. METHODS: The relationship between age, education, ApoE genotype, MRI examination of the brain, subclinical and clinical cardiovascular disease, and low (<80) score on the Modified Mini-Mental State Examination (3MSE, as modified by Teng and Chui) was evaluated for 3469 black and white participants in the Cardiovascular Health Study (CHS) in years 5 and 6 of the study. The participants were followed for up to 3 years. RESULTS: The prevalence of scores <80 in years 5 and 6 of the CHS was 8.2% for participants without and 20.4% for those with prior history of stroke. Age, race, and education were important determinants of low 3MSE scores. The prevalence of ApoE-4 (odds ratio [OR], 1.6 [1.1 to 2.1]) was directly related to scores <80, as was high ventricular volume (OR, 1.6 [1.2 to 2.3]), high white matter grade (OR, 1.4 [1.1 to 1.9]), and infarctlike lesions (OR, 1.6 [1.2 to 2.1]) on the MRI in the multivariate analysis. A five-point or greater decline in scores over up to 3 years was more often observed for participants with low 3MSE scores at year 5, at older ages, with lower education, and experiencing incident stroke (OR, 3.6 [1.2 to 10.6]), ApoE-4 genotype (OR, 1.8 [1.4 to 2.3]), and with MRI findings of high ventricular volume (OR, 2.0 [1.5 to 2.7]), and infarctlike lesions (OR, 1.2 [0.9 to 1.5]). CONCLUSIONS: These results demonstrate that vascular changes on MRI, measures of brain atrophy, ApoE-4, and age, education, and race are associated with low cognitive scores among older individuals. The MRI of the brain provides valuable information related to cognitive tests and decline over time. The potential exists for using MRI measurements to identify high-risk individuals for dementia and to test potential interventions to reduce the risk of dementia.     

Category effects in temporal visual search.

When subjects identify a target during rapid serial visual presentation (RSVP), they show a reduced ability to detect a subsequent probe stimulus relative to when they ignore the target. The present study demonstrated an effect of target/probe categorical relation upon this probe detection deficit (attentional blink). Experiment 1 used letters for both target and probe, replicating the general methods and results of Raymond, Shapiro, and Arnell (1992). Experiment 2 varied target/probe categorical relation via instructional set: The target was referred to as the letter 'oh', whereas for other subjects it was referred to as the number 'zero.' Treating O as a number attenuated the probe detection deficit. This different-category attenuation was confirmed in Experiment 3 where the target was a letter and the probe was a number. The observed category effect suggests that the probe detection deficit in RSVP may map a time course from spreading intra-category inhibition following temporal target selection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A survey of energy drink consumption patterns among college students

Background  

Energy drink consumption has continued to gain in popularity since the 1997 debut of Red Bull, the current leader in the energy drink market. Although energy drinks are targeted to young adult consumers, there has been little research regarding energy drink consumption patterns among college students in the United States. The purpose of this study was to determine energy drink consumption patterns among college students, prevalence and frequency of energy drink use for six situations, namely for insufficient sleep, to increase energy (in general), while studying, driving long periods of time, drinking with alcohol while partying, and to treat a hangover, and prevalence of adverse side effects and energy drink use dose effects among college energy drink users.     

16-Year creep of polyethylene and PVC

Creep tests at constant values of tensile stress, temperature, and relative humidity for two thermoplastics were conducted for approximately 132,000 hr. The strains, ?, for the first 2000 hr of time, t, were described by an equation of the form ? = ?^o + ?⁺tⁿ where all other symbols are constants. This equation was found to predict the creep of poly(vinyl chloride) for approximately 132,000 hr with reasonable accuracy. The predicted strains for polyethylene (density 0.924) were somewhat low. Strains during unloading and reloading after 90,000 hr of creep were predicted reasonably well by the Boltzmann superposition principle.     

Inhibition of monoamineoxidase and day-night-rhythm: correlation of physiological and biochemical parameters (author's transl)

The motor activity of rats following medication with monoamine-oxidase inhibitors was registered continuously over a period of nine days. At the same time the enzyme activity of monoamineoxidase (MAO) form A and B and the concentration of serotonin, tryptophan, 5-hydroxyindolacetic acid and norepinephrine were measured in brain stem and hippocampi. We draw the following conclusions: 1. The rhythmic changes in the levels of serotonin and norepinephrine play a minor role in the circadian rhythm. 2. MAO-inhibitors influence the timing mechanism. A relationship between this finding and the therapeutic effect on depressed patients is discussed. 3 Dopaminergic neurons antagonize the activation by adrenergic neurons during the dark-period.     

Investigation of leakage characteristics of PbSnTes̵bndPbTe inverted heterostructure diodes

The results of a study of the overall electrical characteristics of PbSnTe diodes are presented and interpreted on the basis of a simple p-n junction model. These diodes are made from a PbSnTe epilayer grown by a liquid-phase epitaxy technique on a PbTe wafer substrate. The diodes have a 50% spectral cutoff at 11.5 μm when operated at 85K, which shifts to 14.5 μm at T = 15K. Major contributions to the bulk current are diffusion current at T > 80K, and generation-recombination current for 80 >T ? 30K. Surface related leakage is predominant at T < 30 K for small area diodes (A < 1 × 10^?4 cm²) at low bias voltage. Bulk defect related leakage contributes heavily the large area diodes (A > 1 × 10^?3 cm²) at T ? 60K.