Scaling Analysis of Solving Algorithms for Canonical Problem of Dispatching in the Context of Dynamic Programming

The paper analyses computational model based on dynamic programming for platforms with multicore processors and heterogeneous architectures with FPGA. The models are applied for solving a canonical problem of dispatching where the computation time significantly depends on the problem scale factor. The parallel algorithms of NP-hard problem of dispatching are complicate and require intensive RAM data exchange. In order to reduce the computation time, it is suggested to use FPGA as a coprocessor providing massively parallel computation and increase the operational performance of the system in one order

Optical and X-ray scattering studies of the electric field-induced orientational order in colloidal suspensions of pigment nanorods

© 2018 Elsevier B.V. Under pulsed or a.c. electric fields, colloidal suspensions of nanorods can show strong electro-optic effects, such as the Kerr effect, with fast response times (a few ms), which makes them good candidates for some commercial applications. For this purpose, suspensions of Pigment red 176 nanorods in dodecane were recently developed and their physical properties have been studied. We report here on the investigation of the orientational order induced by electric fields in isotropic suspensions of pigment nanorods by three different techniques: transient electric birefringence, transient electric dichroism, and in-situ small-angle X-ray scattering under electric field (“Electro-SAXS”). We show that, in spite of the apolar character of the solvent, the Maxwell-Wagner-O'Konski mechanism (i.e. the polarization of the counter-ion cloud around each particle) is responsible for the field-induced alignment of the nanorods. Although the particles are only weakly charged and the dielectric constant of dodecane is low, the pigment nanorods effectively behave as metallic particles in an insulating matrix and reach strong values (S ~0.5) of the induced nematic order parameter at moderate field amplitudes (~1 V/μm). This study confirms the feasibility of using suspensions of Pigment red 176 nanorods in dodecane for electro-optic applications

Drag on particles in a nematic suspension by a moving nematic-isotropic interface

We report the first clear demonstration of drag on colloidal particles by a moving nematic-isotropic interface. The balance of forces explains our observation of periodic, strip-like structures that are produced by the movement of these particles

Etude de la dynamique et du désordre de surface des cristaux liquides nématiques

L'objectif de cette thèse est d'étudier la dynamique et le désordre spatial de l'orientation de l'axe facile, d'un cristal liquide nématique. La première partie du manuscrit est consacrée à l'étude de la dynamique de l'axe facile. Cette dynamique est généralement décrite au niveau moléculaire par deux procédés différents impliquant un mécanisme d'adsorption / désorption (AD) à la surface et la relaxation conformationelle d'un polymère. Nous avons élaboré une expérience et un modèle originaux capables de séparer l'influence de ces deux mécanismes microscopiques. Dans la deuxième partie, nous avons caractérisé statistiquement le désordre orientationnel de l'axe de facile pour différentes couches d'ancrage. Le désordre a des propriétés universelles, c'est à dire qu'il est le même sur toutes les surface analysées. Nous avons ensuite construit un modèle basé sur le quenching en surface des fluctuations nématique orientationnelles causé par le processus d'AD. Dans la dernière partie, nous avons mis en place une méthode avec une résolution spatiale et temporelle capable de capturer l'orientation moyenne de l'axe facile et sa distribution spatiale en fonction du temps. Nous montrons que le glissement de l'axe facile moyen se produit avec un changement relativement faible de son désordre spatial.The aim of this PhD is to investigate the dynamics and the spatial disorder of the easy axis orientation, in the case of a nematic liquid crystal. The first part of the manuscript is devoted to the study of the easy axis dynamics. This dynamics is usually described at molecular level by two different processes involving adsorption/desorption (AD) at the surface and polymer conformal relaxations. We devise an original experiment and we build a general model able to separate the influence of these two microscopic mechanisms. In the second part, we statistically characterize the orientational disorder of the easy axis in a whole set of different anchoring layers. This disorder is found to have universal properties, i.e. it is the same on all the analyzed layers. We then build up a model based on the surface quenching of the nematic orientational fluctuations due to the AD-process. In the final part, we set up a method with spatial and temporal resolution capturing the average easy axis orientation and its spatial distribution as function of time. We show that the drift of the average easy axis occurs with a relatively small change of its spatial disorder.MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Dynamics of Molecular Exchange between Aligning Adsorbed Film of Liquid Crystal and the Bulk

The liquid crystal(LC) originally filled in thin cells is replaced by a different LC having a drastically different pretilt angle. The mechanism of desorption/adsorption of LC molecules from/on the adsorbed LCfilm at the substrate changes the composition of the adsorbed layer and thus the pretilt angle. The time dependence of molecular pretilt angle at solid surfaces of homogeneously aligned LC cells is measured. The characteristic molecular exchange time depends on the coefficients of desorption of the first LC. The results presented here provide an important insight into the molecular exchange between solid surface and bulk fluid.</p

Quenched disorder of a nematic liquid crystal under a magnetic field

International audienceWe report measurements and theoretical predictions on the effect of an aligning magnetic field on the orientational disorder of a nematic liquid crystal in contact with isotropic solid substrates. Different types of substrates present a similar disorder and a similar dependency on the magnetic field amplitude, i.e. a decreasing of the angular distribution widths and spatial correlation lengths. Measurements are in qualitative agreement with a theory where the orientational disorder emerges from the competition between the aligning magnetic torque and the disorienting thermal fluctuations during the adsorption of the liquid crystal molecules on the substrate

ПРЕОДОЛЕНИЕ ФАРМАКОРЕЗИСТЕНТНОСТИ ПРИ ДЕПРЕССИИ НА ФОНЕ ВЫРАЖЕННОЙ ГИПЕРКОРТИЗОЛЕМИИ: ОБЗОР ЛИТЕРАТУРЫ И КЛИНИЧЕСКИЙ СЛУЧАЙ

In patients with major depression, there is well-known dysregulation of the HPA axis, including GR resistance, hypercortisolism, aberrant negative cortisol feedback, presenting itself as positive standard 1 mg dexamethasone suppression test, absence of nighttime cortisol suppression. Those HPA axis disturbances are more pronounced in cases with severe depression, and/or with melancholic features or psychosis, and in cases where treatment resistance is documented or suspected. Severe HPA axis disturbances may themselves predispose patients to treatment resistance or be the main reason for it. One method to overcome treatment resistance in such cases is using antiglucocorticoid therapy (for example, inhibitors of cortisol biosynthesis, like ketoconazole, or GR antagonist mifepristone, or a short course of high-dose synthetic glucocorticoid dexamethasone to suppress the HPA axis overactivity). In this article, we present a case in which the treatment resistance in a patient with severe psychotic major depression and severe hypercortisolemia was successfully overcomed by sequential use of high-dose dexamethasone (20 mg/day x 4 days) and high-dose mifepristone (600 mg/day for 14 days).У пациентов с депрессивными состояниями нередко отмечаются те или иные нарушения в работе оси ГГН (в частности, гиперкортизолемия, резистентность GR рецепторов, нарушение работы системы отрицательной обратной связи, проявляющееся в положительных результатах стандартного 1 мг дексаметазонового теста, отсутствие ночного снижения уровня кортизола или недостаточное его снижение). Особенно часто это наблюдается при тяжёлых депрессиях, при депрессиях, протекающих с психозом, с меланхолической симптоматикой или синдромом деперсонализации-дереализации. Это может служить одной из причин терапевтической резистентности. Одним из методов преодоления резистентности в подобных случаях является использование антиглюкокортикоидной терапии (например, блокатора биосинтеза кортизола – кетоконазола, или антагониста глюкокортикоидных рецепторов – мифепристона, или короткого курса высоких доз дексаметазона с целью супрессии собственной продукции кортизола). В данной статье мы представляем клинический случай, демонстрирующий успешное преодоление терапевтической резистентности у депрессивного пациента с гиперкортизолемией при помощи последовательного применения дексаметазона и мифепристона

Fast Birefringent Mode Stressed Liquid Crystal

We report a stressed liquid crystal (SLC) that produce a large shift in phase retardation at submillisecond speeds. The SLC consists of uniformly aligned micro-domains of a liquid crystal dispersed in a polymer structure. Mechanical stress produces uniform alignment, essentially eliminates light scattering, and substantially improves the electro-optic performance. A 22-μm-thick SLC film switches more than 2μm of phase retardation in less than 1ms. The system has a linear voltage response with essentially no hysteresis.</p

Enhanced two-beam coupling in colloids of ferroelectric nanoparticles in liquid crystals

We report on the first, to the best of our knowledge, studies of photorefraction in nematic liquid crystal (LC) doped with nanoferroelectric particles. We found the strong enhancement of two-beam coupling in the colloid of ferroelectric nanoparticles in LC. The effect originated from an increased birefringence of the colloid and a stronger LC reorientation torque. Our measurements allowed us to suggest that increased birefringence is caused by the contribution of polarizability anisotropy of the ferroelectric particles. Stronger reorientation torque is caused by the permanent dipole moment of the particles contributing to the dielectric anisotropy of the colloid a col. The enhancement of two-beam coupling in LCs by doping with ferroelectric nanoparticles at extremely small concentration shows the strong potential of ferroelectric nanoparticles for improving the optical response of LCs, especially for those materials where a method of chemical synthesis has reached its limit