We investigated the effect of mobile phone use on the auditory sensory memory in children. Auditory event-related potentials (ERPs), P1, N2, mismatch negativity (MMN), and P3a, were recorded from 17 children, aged 11–12 years, in the recently developed multi-feature paradigm. This paradigm allows one to determine the neural change-detection profile consisting of several different types of acoustic changes. During the recording, an ordinary GSM (Global System for Mobile Communications) mobile phone emitting 902 MHz (pulsed at 217 Hz) electromagnetic field (EMF) was placed on the ear, over the left or right temporal area (SAR1g = 1.14 W/kg, SAR10g = 0.82 W/kg, peak value = 1.21 W/kg). The EMF was either on or off in a single-blind manner. We found that a short exposure (two 6 min blocks for each side) to mobile phone EMF has no statistically significant effects on the neural change-detection profile measured with the MMN. Furthermore, the multi-feature paradigm was shown to be well suited for studies of perception accuracy and sensory memory in children. However, it should be noted that the present study only had sufficient statistical power to detect a large effect size.
В рамках линейной теории волн в сжимаемой атмосфере, находящейся в поле тяжести, найдено семейство профилей скорости звука, при котором волновое поле может быть представлено бегущей волной так, что отражение отсутствует. Вертикальный поток волновой энергии на таких безотражательных профилях сохраняется, что доказывает возможность переноса энергии на большие расстояния.
The atomic-scale diffusion of water in the presence of several lipid bilayers mimicking biomembranes is characterized via unconstrained molecular dynamics (MD) simulations. Although the overall water dynamics corresponds well to literature data – namely, the efficient braking near polar head groups of lipids - a number of interesting and biologically relevant details observed in this work have not been sufficiently discussed so far. For instance, the fact that waters “sense” the membrane unexpectedly early – before water density begins to decrease. In this “transitional zone” the velocity distributions of water and their H-bonding patterns deviate from those in the bulk solution. The boundaries of this zone are well preserved even despite the local (<1 nm size) perturbation of the lipid bilayer, thus indicating a decoupling of the surface and bulk dynamics of water. This is in excellent agreement with recent experimental data. Near the membrane surface, water movement becomes anisotropic – solvent molecules preferentially move outward the bilayer. Deep in the membrane interior, the velocities can even exceed those in the bulk solvent and undergo large-scale fluctuations. The analysis of MD trajectories of individual waters in the middle part of the acyl chain region of lipids reveals a number of interesting rare phenomena, such as the fast (c.a. 50 ps) breakthrough across the membrane or long-time (up to 750 ps) “roaming” between lipid leaflets. The analysis of these events was accomplished to delineate the mechanisms of spontaneous water permeation inside the hydrophobic membrane core. It was shown that such nontrivial dynamics of water in an “alien” environment is driven by the dynamic heterogeneities of the local bilayer structure and the formation of transient atomic-scale “defects” in it. The picture observed in lipid bilayers is drastically different from that in a primitive membrane mimic – a hydrated cyclohexane slab. The possible biological impact of such phenomena in equilibrated lipid bilayers is discussed.
Настоящее сообщение посвящено описанию и первичному анализу находки костей байбака в слоях первых веков нашей эры в греческом городе Пантикапей. Это первое сообщение о находке костей в самой восточной части Крымского полуострова (Керченский полуостров). Хотя животное могло быть привезено с северных берегов Аральского и Черного морей из-за ценного мяса и жира, сохраняется большая вероятность его обитания в этой области полуострова в начале нашей эры
On the investigation of human osseal remains, found in Savvatiev Monastery (Tver Region, Russia)