Switching dynamics of surface stabilized ferroelectric liquid crystal cells: effects of anchoring energy asymmetry

We study both theoretically and experimentally switching dynamics in surface stabilized ferroelectric liquid crystal cells with asymmetric boundary conditions. In these cells the bounding surfaces are treated differently to produce asymmetry in their anchoring properties. Our electro-optic measurements of the switching voltage thresholds that are determined by the peaks of the reversal polarization current reveal the frequency dependent shift of the hysteresis loop. We examine the predictions of the uniform dynamical model with the anchoring energy taken into account. It is found that the asymmetry effects are dominated by the polar contribution to the anchoring energy. Frequency dependence of the voltage thresholds is studied by analyzing the properties of time-periodic solutions to the dynamical equation (cycles). For this purpose, we apply the method that uses the parameterized half-period mappings for the approximate model and relate the cycles to the fixed points of the composition of two half-period mappings. The cycles are found to be unstable and can only be formed when the driving frequency is lower than its critical value. The polar anchoring parameter is estimated by making a comparison between the results of modelling and the experimental data for the shift vs frequency curve. For a double-well potential considered as a deformation of the Rapini-Papoular potential, the branch of stable cycles emerges in the low frequency region separated by the gap from the high frequency interval for unstable cycles.Comment: 35 pages, 15 figure

Ferroelectric C* phase induced in a nematic liquid crystal matrix by a chiral non-mesogenic dopant

We report on a ferroelectric chiral smectic C (C*) phase obtained in a mixture of a nematic liquid crystal (NLC) and a chiral nonmesogenic dopant. The existence of C* phase was proven by calorimetric, dielectric and optical measurements, and also by X-rays analysis. The smectic C* which is obtained in such a way can flow, allowing to restore the ferroelectric liquid crystal layer structure in the electro-optical cells after action of the mechanical stress, as it happens with the cells filled with NLC. The proposed method of obtaining smectic C* material allows us to create innovative electro-optical cell combining the advantages of NLC (mechanical resilience) and smectic C* (high switching speed

\delta-derivations of n-ary algebras

We defined \delta-derivations of n-ary algebras. We described \delta-derivations of (n+1)-dimensional n-ary Filippov algebras and simple finite-dimensional Filippov algebras over algebraically closed field zero characteristic, and simple ternary Malcev algebra M_8. We constructed new examples of non-trivial \delta-derivations of Filippov algebras and new examples of non-trivial antiderivations of simple Filippov algebras.Comment: 12 page

In-plane switching deformed helix ferroelectric liquid crystal display cell

As it is well known the principal advantages of in-plane switching (IPS) liquid crystal display cells is the colot accuracy due to the small gamma and color shifts, and since the director lies in the substrates plane, the viewing angle is large and symmetric. Together with this, the production of IPS-displays based on nematic liquid crystals is associated with the solution of rather complex technological problems caused by the need to form a grid of interdigitated electrodes.In this message, we draw attention for the first time to the fact that the IPS electro-optical switching is a natural and inherent feature of a conventional planar-oriented display cell based on the deformed helix ferroelectric liquid crystal effect (DHFLC-effect). In such a cell with continuous (and not interdigital) electrodes, the main optical axis is deflected in the plane of the substrates under the electric field E action. Measured dependence of light transmittance T(E) and calculations results can be argued that in DHFLC cell there is the IPS electro-optical mode. IPS switching operates in kilohertz frequency range providing contrast ratio more than 200:1 in monochromatic light.The paper will consider possible applications of the effect under consideration in display and photonic devices

Comparative Characteristics of the Metabolic Syndrome Prevalence in Patients With Schizophrenia in Three Western Siberia Psychiatric Hospitals

Objective: The purpose of this study was to compare the prevalence of MetS and the associated sociodemographic, clinical, and pharmacotherapeutic characteristics of patients with schizophrenia in three psychiatric hospitals in the West Siberian region. Methods: Patients with a clinical diagnosis of schizophrenia (ICD-10: F20) and an age between 18 and 60 years were included in the study after giving informed consent. Metabolic syndrome was diagnosed according to the International Diabetes Federation criteria. This research was carried out at three Western Siberian psychiatric hospitals in Kemerovo, Tomsk, and Omsk. The study population included respectively 94, 131, and 91 inpatients with schizophrenia. We carried out schizophrenia symptoms assessment by PANSS, antipsychotic therapy evaluation, anthropometry, and biochemical analysis. Statistical Analysis included the Shapiro–Wilk test, non-parametric Kruskal–Wallis H-test for independent samples, Mann–Whitney U-test for independent samples, the chi-square test, stepwise multiple regression analyses. The level of significance was p < 0.05. Results: The metabolic syndrome prevalence was higher among patients in Tomsk (36.6%), compared with Kemerovo (20.2%, p = 0.008) or Omsk (18.7%, p = 0.004), mainly due to the high prevalence of abdominal obesity, while men from Tomsk were more susceptible to this condition than men from other regions (p < 0.05). Patients from Omsk had the highest severity schizophrenia symptoms according to PANSS, and patients from Tomsk had the lowest severity of positive symptoms according to PANSS. Patients from Tomsk had the minimum duration of antipsychotic therapy compared with the patient from Kemerovo (p = 0.017) and from Omsk (p = 0.000019), but most patients from Tomsk received second-generation atypical antipsychotics, while patients from Omsk received mainly conventional antipsychotics (p = 0.0001). Multiple regression analysis showed that metabolic syndrome associated with schizophrenia duration and body mass index, although the association was not so strong (adjusted R(2) = 0.2435, p < 0.0001). Discussion: The study illustrates that in different psychiatric hospitals within the same region, the prevalence of metabolic syndrome in patients with schizophrenia can vary significantly, which dictates the need to look for opportunities to minimize the risk of its occurrence, taking into account the experience of each hospital

Electro-optical switching of the main optical axis of a ferroelectric liquid crystal spiral nanostructure in a planar-oriented display cell

В известной дисплейной ячейке с нематическим жидким кристаллом (НЖК) и встречно- штыревыми электродами на одной из стеклянных подложек реализуется режим переключения «In-Plane Switching» (IPS), при котором главная оптическая ось НЖК переориентируется в параллельной подложкам плоскости, обеспечивая наиболее корректную цветопередачу при разных углах обзора, вплоть до 178 ° пo горизонтали и вертикали. К сожалению, создание гребенки металлических электродов усложняет и удорожает технологический процесс и вызывает ухудшение контрастности изображения. В то же время экспериментальные результаты и расчеты, основанные на классической электрооптике кристаллов, свидетельствуют, что электрооптическое переключение в режиме IPS является естественной и неотъемлемой особенностью обычной (со сплошными электродами) дисплейной ячейки с планарно-ориентированным слоем сегнетоэлектрического жидкого кристалла (СЖК), в котором реализуется эффект деформированной электрическим полем спиральной наноструктуры СЖК (DHF-эффект). В такой ячейке переориентация главной оптической оси под воздействием слабого электрического поля тоже происходит в плоскости подложек, если СЖК имеет малый шаг (около 100 нм и менее) и большой угол наклона молекул в слое (около 38 ° и более). Измеренные в данной работе зависимости коэффициента пропускания света СЖК-ячейкой подтвердили достижение электрооптического режима IPS в ячейке DHF СЖК, причем частота модуляции света составила 1 кГц. Таким образом, при сохранении всех достоинств IPS-режима, известных в НЖК, реализация его в СЖК позволяет дополнительно получить технологические преимущества и многократный выигрыш в частоте модуляции

ЭЛЕКТРООПТИЧЕСКОЕ ПЕРЕКЛЮЧЕНИЕ ГЛАВНОЙ ОПТИЧЕСКОЙ ОСИ СПИРАЛЬНОЙ НАНОСТРУКТУРЫ СЕГНЕТОЭЛЕКТРИЧЕСКОГО ЖИДКОГО КРИСТАЛЛА В ПЛАНАРНО- ОРИЕНТИРОВАННОЙ ДИСПЛЕЙНОЙ ЯЧЕЙКЕ

In a known display cell with the nematic liquid crystal (NLC) and interdigital electrodes on one of the glass substrates, the “In-Plane Switching” (IPS) mode is implemented, in which the NLC main optical axis reorients in a plane parallel to substrates, providing the most correct color reproduction at different angles view, up to 178 ° horizontally and vertically. Unfortunately, the creation of interdigital metal electrodes complicates and increases the technological process cost and causes a decrease in image contrast. At the same time, experimental results and calculations based on classical electro-optics of crystals indicate that electrooptical switching in the IPS mode is a natural and intrinsic feature of a conventional (with continuous electrodes) display cell with a planar-oriented layer of the ferroelectric liquid crystal (FLC), in which the effect of the deformed (by the electric field) helix FLC nanostructure is realized (DHF effect). In such a cell, the reorientation of the main optical axis under the influence of a weak electric field also occurs in the substrate plane if the FLC has a small pitch (about 100 nm or less) and a large tilt angle of molecules in the layer (about 38 ° or more). The dependences of the FLC cell light transmittance measured in this work, confirmed the achievement of the IPS electro-optical mode in the DHF FLC cell; moreover, the light modulation frequency was 1 kHz. Thus, while maintaining all the advantages of the IPS mode known in NLC, its implementation in FLC allows additionally obtaining technological advantages and multiple increase in modulation frequency.В известной дисплейной ячейке с нематическим жидким кристаллом (НЖК) и встречно- штыревыми электродами на одной из стеклянных подложек реализуется режим переключения «In-Plane Switching» (IPS), при котором главная оптическая ось НЖК переориентируется в параллельной подложкам плоскости, обеспечивая наиболее корректную цветопередачу при разных углах обзора, вплоть до 178 ° пo горизонтали и вертикали. К сожалению, создание гребенки металлических электродов усложняет и удорожает технологический процесс и вызывает ухудшение контрастности изображения. В то же время экспериментальные результаты и расчеты, основанные на классической электрооптике кристаллов, свидетельствуют, что электрооптическое переключение в режиме IPS является естественной и неотъемлемой особенностью обычной (со сплошными электродами) дисплейной ячейки с планарно-ориентированным слоем сегнетоэлектрического жидкого кристалла (СЖК), в котором реализуется эффект деформированной электрическим полем спиральной наноструктуры СЖК (DHF-эффект). В такой ячейке переориентация главной оптической оси под воздействием слабого электрического поля тоже происходит в плоскости подложек, если СЖК имеет малый шаг (около 100 нм и менее) и большой угол наклона молекул в слое (около 38 ° и более). Измеренные в данной работе зависимости коэффициента пропускания света СЖК-ячейкой подтвердили достижение электрооптического режима IPS в ячейке DHF СЖК, причем частота модуляции света составила 1 кГц. Таким образом, при сохранении всех достоинств IPS-режима, известных в НЖК, реализация его в СЖК позволяет дополнительно получить технологические преимущества и многократный выигрыш в частоте модуляции

Association of COMT gene polymorphisms with Parkinson's disease

Parkinson’s disease (PD) is one of the most serious and widespread neurodegenerative disorders. Genetic susceptibility plays a significant role in the development of PD.The aim of our study was to investigate associations between single nucleotide polymorphisms (SNPs) of the COMT gene coding dopamine catabolism enzyme and Parkinson’s disease.Materials and methods. In this study seven SNPs (rs4680, rs6269, rs4633, rs4818, rs769224, rs165774, rs174696) of COMT were genotyped. 232 patients with PD and 127 healthy individuals in the Siberian region of Russia were examined. Venous blood samples were drawn as a marker of PD. Statistical differences in the prevalence of alleles and genotypes between groups of patients were assessed using IBM SPSS Statistics 23.1 software.Results. A significant association between the rs165774 polymorphism and PD was observed. Our study demonstrates that polymorphisms in the COMT gene may play an important role in the pathophysiology of Parkinson’s disease

Study of Spin and Decay-Plane Correlations of W Bosons in the e+e- -> W+W- Process at LEP

Data collected at LEP at centre-of-mass energies \sqrt(s) = 189 - 209 GeV are used to study correlations of the spin of W bosons using e+e- -> W+W- -> lnqq~ events. Spin correlations are favoured by data, and found to agree with the Standard Model predictions. In addition, correlations between the W-boson decay planes are studied in e+e- -> W+W- -> lnqq~ and e+e- -> W+W- -> qq~qq~ events. Decay-plane correlations, consistent with zero and with the Standard Model predictions, are measured