9 research outputs found

    Parametric Oscillations of a Thermal Field During Explosive Crystallization of Amorphous Films

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    Изучены тепловые процессы, происходящие при взрывной кристаллизации аморфных пленок, напыленных на подложку. Представлены результаты численного моделирования параметрических колебаний теплового поля в системе «фазовая граница – подложка». Рассмотрены стационарный и волновой режимы возбуждения горячих центров кристаллизации в аморфной фазе. Расчеты выполнены для аморфной пленки германия. Установлены основные физические факторы, определяющие амплитудно-частотные свойства данного процесса: толщина пленки, температура подложки и скорость фазовой границы кристаллизации. Указаны примеры возникновения резонансных ситуаций. Рассмотрены колебания параметрической системы, которая испытывает внешнее воздействие в режиме биений. Для этой системы по-строен трехмерный фазовый портрет, демонстрирующий ее динамические свойства. При наличии спектра частот структура фазовых траекторий в основном аналогична варианту колебаний на одной частоте.The thermal processes occurring during explosive crystallization of amorphous films deposited on a substrate are studied. The results of numerical modeling of parametric oscillations of a thermal field in the “phase boundary – substrate” system are presented. The stationary and wave modes of hot crystallization centers in the amorphous phase are considered. The calculations are performed for an amorphous germanium film. The main physical factors determining the amplitude and frequency properties of this process are established: film thickness, substrate temperature, and crystallization phase boundary rate. Examples of the resonant situation occurrence are indicated. The parametric system oscillations, which has external influence in the beating mode, are considered. A three-dimensional phase portrait is constructed for this system, demonstrating its dynamic properties. In the presence of a frequency spectrum, the structure of phase trace is basically similar to the variant of oscillations at one frequency

    BDNF DNA methylation changes as a biomarker of psychiatric disorders : literature review and open access database analysis

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    Brain-derived neurotrophic factor (BDNF) plays an important role in nervous system development and function and it is well established that BDNF is involved in the pathogenesis of a wide range of psychiatric disorders. Recently, numerous studies have associated the DNA methylation level of BDNF promoters with certain psychiatric phenotypes. In this review, we summarize data from current literature as well as from our own analysis with respect to the correlation of BDNF methylation changes with psychiatric disorders and address questions about whether DNA methylation related to the BDNF can be useful as biomarker for specific neuropsychiatric disorders

    Genome-wide analysis shows association of epigenetic changes in regulators of Rab and Rho GTPases with spinal muscular atrophy severity

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    Spinal muscular atrophy (SMA) is a monogenic disorder that is subdivided into four different types and caused by survival motor neuron gene 1 (SMN1) deletion. Discordant cases of SMA suggest that there exist additional severity modifying factors, apart from the SMN2 gene copy number. Here we performed the first genome-wide methylation profiling of SMA patients and healthy individuals to study the association of DNA methylation status with the severity of the SMA phenotype. We identified strong significant differences in methylation level between SMA patients and healthy controls in CpG sites close to the genes CHML, ARHGAP22, CYTSB, CDK2AP1 and SLC23A2. Interestingly, the CHML and ARHGAP22 genes are associated with the activity of Rab and Rho GTPases, which are important regulators of vesicle formation, actin dynamics, axonogenesis, processes that could be critical for SMA development. We suggest that epigenetic modifications may influence the severity of SMA and that these novel genetic positions could prove to be valuable biomarkers for the understanding of SMA pathogenesis
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