Search results for "Potentials"
showing 10 items of 1072 documents
Phoneme processing skills are reflected in children's MMN responses.
2017
Phonological awareness (PA), the core contributor in phoneme processing abilities, has a link to later reading skills in children. However, the associations between PA and neural auditory discrimination are not clear. We used event-related potential (ERP) methodology and neuropsychological testing to monitor the neurocognitive basis of phonological awareness in typically developing children. We measured 5–6-year-old children's (N=70) phoneme processing, word completion and perceptual reasoning skills and compared their test results to their brain responses to phonemic changes, separately for each test. We found that children performing better in Phoneme processing test showed larger mismatc…
Spiral wave induced numerically using electrical stimulation and comparison with experimental results.
2010
Experiments in vitro on a Microelectrode Array (MEA) platform show that electrical stimulation can provoke the generation of spiral waves in cardiac tissue. Nevertheless, the conditions leading to this artificial fibrillation state remain unclear. In order to have a better understanding of this phenomenon, a numerical simulation study has been conducted. The results obtained with a two-dimensional FitzHugh-Nagumo model proved that it is possible to create spiral waves by adding a stimulation current under certain conditions, which are made explicit.
Physical-mechanical effects of Nd:YAG laser on the surface of sound dental enamel.
1993
Human dental enamel samples were irradiated using a 5 kHz Q-Switched Nd:YAG laser. An increase in Knoop microhardness and modification of the membrane permselectivity were detached. These results and the changes observed by SEM, can be connected with the fusion of the enamel surface.
Effect of Organic Tin Compounds on Electric Properties of Model Membranes
2006
The objective of the present work was to investigate the effect of selected organic tin compounds and potassium chloride (used as a reference substance) on the trans-membrane electric voltage and electric resistance of model membranes, the latter being nitrocellulose filters impregnated with butylene ester of lauric acid. The increasing KCl concentration (in the measurement chambers) caused a rapid rise of the negative trans-membrane voltage, whose value stabilized afterwards. In the case of (C3H7)3SnCl an abrupt maximum of the negative voltage was observed followed by a monotonic drop to zero. In the case of highest concentrations of this compound the voltages, after having reached zero, c…
Ion conduction in the KcsA potassium channel analyzed with a minimal kinetic model.
2004
We use a model by Nelson to study the current-voltage and conductance-concentration curves of bacterial potassium channel KcsA without assuming rapid ion translocation. Ion association to the channel filter is rate controlling at low concentrations, but dissociation and transport in the filter can limit conduction at high concentration for ions other than ${\mathrm{K}}^{+}$. The absolute values of the effective rate constants are tentative but the relative changes in these constants needed to qualitatively explain the experiments should be of significance.
Simulation of Young’s moduli for hexagonal ZnO [0 0 0 1]-oriented nanowires: first principles and molecular mechanical calculations
2017
The authors thank A Gulans, B Polyakov and S Vlassov for stimulating discussions. This study has been supported by the ERA.Net RUS Plus project No. 237 Watersplit. AB, RE and SL acknowledge the financial support by the Russian Foundation for Basic Research (Grant No. 17-03-00130-a) and the assistance of the Saint Petersburg State University Computer Center in the accomplishment of high-performance computations.
Investigating the effects of musical training on functional brain development with a novel Melodic MMN paradigm.
2013
Sensitivity to changes in various musical features was investigated by recording the mismatch negativity (MMN) auditory event-related potential (ERP) in musically trained and nontrained children semi-longitudinally at the ages of 9, 11, and 13 years. The responses were recorded using a novel Melodic multi-feature paradigm which allows fast (<15 min) recording of an MMN profile for changes in melody, rhythm, musical key, timbre, tuning and timing. When compared to the nontrained children, the musically trained children displayed enlarged MMNs for the melody modulations by the age 13 and for the rhythm modulations, timbre deviants and slightly mistuned tones already at the age of 11. Also, a …
Auditory Profiles of Classical, Jazz, and Rock Musicians: Genre-Specific Sensitivity to Musical Sound Features
2016
When compared with individuals without explicit training in music, adult musicians have facilitated neural functions in several modalities. They also display structural changes in various brain areas, these changes corresponding to the intensity and duration of their musical training. Previous studies have focused on investigating musicians with training in Western classical music. However, musicians involved in different musical genres may display highly differentiated auditory profiles according to the demands set by their genre, i.e., varying importance of different musical sound features. This hypothesis was tested in a novel melody paradigm including deviants in tuning, timbre, rhythm,…
Regulation of Calcium Channel Activity by Lipid Domain Formation in Planar Lipid Bilayers
2003
The sarcoplasmic reticulum channel (ryanodine receptor) from cardiac myocytes was reconstituted into planar lipid bilayers consisting of 1-palmitoyl-2-oleoyl-phosphatidylethanolamine (POPE) and 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) in varying ratios. The channel activity parameters, i.e., open probability and average open time and its resolved short and long components, were determined as a function of POPE mole fraction (X(PE)) at 22.4 degrees C. Interestingly, all of these parameters exhibited a narrow and pronounced peak at X(PE) approximately 0.80. Differential scanning calorimetric measurements on POPE/POPC liposomes with increasing X(PE) indicated that the lipid bilayer ente…
Membrane potential-dependent binding of polysialic acid to lipid monolayers and bilayers
2013
AbstractPolysialic acids are linear polysaccharides composed of sialic acid monomers. These polyanionic chains are usually membrane-bound, and are expressed on the surfaces of neural, tumor and neuroinvasive bacterial cells. We used toluidine blue spectroscopy, the Langmuir monolayer technique and fluorescence spectroscopy to study the effects of membrane surface potential and transmembrane potential on the binding of polysialic acids to lipid bilayers and monolayers. Polysialic acid free in solution was added to the bathing solution to assess the metachromatic shift in the absorption spectra of toluidine blue, the temperature dependence of the fluorescence anisotropy of DPH in liposomes, t…