Holographic interferometry under phase distortions

An impact of non-stationary phase distortions in transfer section of a holographic interferometer on the quality of formed interference fringes in an interferogram was under investigation. A mathematical model to analyze this influence was proposed. The conclusions based on the model were made about the possibility to observe interference fringes under phase noise in the broad ranges. Theoretical estimations were involved to analyze the experimental data. For that purpose, a modified holographic interferometer scheme with regular bundle of multimode lightguiding fibers in the transfer section was used. Investigated here was the possibility to use the scheme under possible deformations of the bundle between the two interferometric exposures. Experimentally proved was the capability of the holographic interferometer with flexible lightguiding bundle to operate under reasonable deformations of the bundle and even under non-rigid fixation of bundle body

Targeting Mll1 H3K4 methyltransferase activity to guide cardiac lineage specific reprogramming of fibroblasts

Generation of induced cardiomyocytes (iCMs) directly from fibroblasts offers a great opportunity for cardiac disease modeling and cardiac regeneration. A major challenge of iCM generation is the low conversion rate. To address this issue, we attempted to identify small molecules that could potentiate the reprogramming ability towards cardiac fate by removing inhibitory roadblocks. Using mouse embryonic fibroblasts as the starting cell source, we first screened 47 cardiac development related epigenetic and transcription factors, and identified an unexpected role of H3K4 methyltransferase Mll1 and related factor Men1 in inhibiting iCM reprogramming. We then applied small molecules (MM408 and MI503) of Mll1 pathway inhibitors and observed an improved efficiency in converting embryonic fibroblasts and cardiac fibroblasts into functional cardiomyocyte-like cells. We further observed that these inhibitors directly suppressed the expression of Mll1 target gene Ebf1 involved in adipocyte differentiation. Consequently, Mll1 inhibition significantly decreased the formation of adipocytes during iCM induction. Therefore, Mll1 inhibitors likely increased iCM efficiency by suppressing alternative lineage gene expression. Our studies show that targeting Mll1 dependent H3K4 methyltransferase activity provides specificity in the process of cardiac reprogramming. These findings shed new light on the molecular mechanisms underlying cardiac conversion of fibroblasts and provide novel targets and small molecules to improve iCM reprogramming for clinical applications

Some peculiarities of the associative holographic image formation and quality: the comparative analysis

The peculiarities of associative holographic image formation at the initial image saving stage in different registration media have been studied. It is shown that the recovered associative holographic image quality can be theoretically predicted and is defined by the recovering beam area. The experiment and simulation results on the associative holographic image quality with the different reconstruction beam area are shown.Исследованы особенности формирования ассоциативного голографического изображения в процессе начальной записи информации в различных регистрирующих средах. Показано, что качество восстановленного ассоциативного изображения может быть теоретически предсказано и определяется площадью восстанавливающего пучка. Представлены результаты экспериментальных исследований и моделирования качества ассоциативного голографического изображения при различных значениях площади восстанавливающего пучка.Досліджено особливості формування асоціативного голографічного зображення у ході початкового запису інформації в різних реєструючих середовищах. Показано, що якість відновленого асоціативного голографічного зображення може бути теоретично передбачена й визначається площею відновлювального пучка. Наведено результати експериментальних досліджень та моделювання якості асоціативного голографічного зображення за різних значень площі відновлювального пучка

Holographic Interferometer as a Correlator of Phase Distortions with Response in the Form of Interference Pattern

Considered in the work are known properties of holographic interferometer as according to the correlator with output signal in the form of interference fringes. It is known that a space correlation has various ratios of intensity between central correlation peak and background part for objects with different phase microrelief of a surface. Correspondingly an interference pattern must have different space distribution of contrast. A magnitude of contrast depends on changes in distribution of microrelief of investigated object, whereas the interference pattern depends on macroscopic modification of a form of the object. Used here is a scheme of Fourier holography with a random phase modulator in signal beam, reference beam is a point source, and restoring beam is the random phase modulator with random phase shift against initial random phase modulator. Also investigated is a recording of holographic interferogram with these random phase modulators. As the results of original theoretical consideration there was obtained an expression for fringe contrast and intensity of correlation peak. This model was tested by simulating of forming of holographic interferogram and reconstruction of the cross-correlation peak with phase distortions of various statistical distributions. Compared here are theoretical results, simulation results, and results obtained in real experiment

Holographic Interferometer as a Correlator of Phase Distortions with Response in the Form of Interference Pattern

Considered in the work are known properties of holographic interferometer as according to the correlator with output signal in the form of interference fringes. It is known that a space correlation has various ratios of intensity between central correlation peak and background part for objects with different phase microrelief of a surface. Correspondingly an interference pattern must have different space distribution of contrast. A magnitude of contrast depends on changes in distribution of microrelief of investigated object, whereas the interference pattern depends on macroscopic modification of a form of the object. Used here is a scheme of Fourier holography with a random phase modulator in signal beam, reference beam is a point source, and restoring beam is the random phase modulator with random phase shift against initial random phase modulator. Also investigated is a recording of holographic interferogram with these random phase modulators. As the results of original theoretical consideration there was obtained an expression for fringe contrast and intensity of correlation peak. This model was tested by simulating of forming of holographic interferogram and reconstruction of the cross-correlation peak with phase distortions of various statistical distributions. Compared here are theoretical results, simulation results, and results obtained in real experiment

BAF250a Protein Regulates Nucleosome Occupancy and Histone Modifications in Priming Embryonic Stem Cell Differentiation

plan (drawing), palace of the upper citade