Microscopic origin of Magnetic Ferroelectrics in Nonlinear Multiferroics

A simple but general microscopic mechanism to understand the interplay between the electric and magnetic degrees of freedom is developed. Within this mechanism, the magnetic structure generates an electric current which induce an counterbalance electric current from the spin orbital coupling. When the magnetic structure is described by a single order parameter, the electric polarization is determined by the single spin orbital coupling parameter, and the material is predicted to be a half insulator. This mechanism provides a simple estimation of the value of ferroelectricity and sets a physical limitation as well.Comment: 4 pages, 1 figur

Analytical Grounds for Modern Theory of Two- Dimensionally Periodic Gratings

36 page(s

Epitaxial checkerboard arrangement of nanorods in ZnMnGaO4 films studied by x-ray diffraction

The intriguing nano-structural properties of a ZnMnGaO4 film epitaxially grown on MgO (001) substrate have been investigated using synchrotron radiation-based x-ray diffraction. The ZnMnGaO4 film consisted of a self-assembled checkerboard (CB) structure with perfectly aligned and regularly spaced vertical nanorods. The lattice parameters of the orthorhombic and rotated tetragonal phases of the CB structure were analyzed using H-K, H-L, and K-L cross sections of the reciprocal space maps measured around various symmetric and asymmetric reflections of the spinel structure. We demonstrate that the symmetry of atomic displacements at the phases boundaries provides the means for coherent coexistence of two domains types within the volume of the film

Non-circular semiconductor nanorings of type I and II: Emission kinetics in the exciton Aharonov-Bohm effect

Transition energies and oscillator strengths of excitons in dependence on magnetic field are investigated in type I and II semiconductor nanorings. A slight deviation from circular (concentric) shape of the type II nanoring gives a better observability of the Aharonov-Bohm oscillations since the ground state is always optically active. Kinetic equations for the exciton occupation are solved with acoustic phonon scattering as the major relaxation process, and absorption and luminescence spectra are calculated showing deviations from equilibrium. The presence of a non-radiative exciton decay leads to a quenching of the integrated photoluminescence with magnetic field.Comment: The first version submitted to Phys. Rev. B on April 16, 2007. Revised (this) version on July 31, 200

\u3ci\u3eIn-Situ\u3c/i\u3e Raman Scattering Studies of Alkali-Doped Single Wall Carbon Nanotubes

Electrochemical doping and in-situ Raman scattering were used to study charge transfer in K- and Li-doped single wall carbon nanotubes (SWNT) as a function of alkali concentration. An 8 cm-1 downshift was observed for the tangential phonon mode of SWNT doped to stoichiometries of KC24 and Li1.25C6. The shift in both systems is reversible upon de-doping despite an irreversible loss of crystallinity. These results indicate that the tangential mode shifts result from electron transfer from alkali dopants to the SWNT, and that these modes are only weakly affected by long-range order within the ropes

The effect of wave-particle interactions on low energy cutoffs in solar flare electron spectra

Solar flare hard X-ray spectra from RHESSI are normally interpreted in terms of purely collisional electron beam propagation, ignoring spatial evolution and collective effects. In this paper we present self-consistent numerical simulations of the spatial and temporal evolution of an electron beam subject to collisional transport and beam-driven Langmuir wave turbulence. These wave-particle interactions represent the background plasma's response to the electron beam propagating from the corona to chromosphere and occur on a far faster timescale than coulomb collisions. From these simulations we derive the mean electron flux spectrum, comparable to such spectra recovered from high resolution hard X-rays observations of solar flares with RHESSI. We find that a negative spectral index (i.e. a spectrum that increases with energy), or local minima when including the expected thermal spectral component at low energies, occurs in the standard thick-target model, when coulomb collisions are only considered. The inclusion of wave-particle interactions does not produce a local minimum, maintaining a positive spectral index. These simulations are a step towards a more complete treatment of electron transport in solar flares and suggest that a flat spectrum (spectral index of 0 to 1) down to thermal energies maybe a better approximation instead of a sharp cut-off in the injected electron spectrum.Comment: 6 pages, 5 figures, accepted by ApJ

Coupling between magnon and ligand-field excitations in magnetoelectric Tb3Fe5O12 garnet

The spectra of far-infrared transmission in Tb3Fe5O12 magnetoelectric single crystals have been studied in the range between 15 and 100 cm-1, in magnetic fields up to 10 T, and for temperatures between 5 and 150 K. We attribute some of the observed infrared-active excitations to electric-dipole transitions between ligand-field split states of Tb3+ ions. Anticrossing between the magnetic exchange excitation and the ligand-field transition occurs at the temperature between 60 and 80 K. The corresponding coupling energy for this interaction is 6 cm-1. Temperature-induced softening of the hybrid IR excitation correlates with the increase of the static dielectric constant. We discuss the possibility for hybrid excitations of magnons and ligand-field states and their possible connection to the magnetoelectric effect in Tb3Fe5O12.Comment: submitted to Phys. Rev. B on May 15th, 201

Динаміка морфофункціональних зрушень підшлункової залози та рівень цитокинів у потомства щурів внаслідок дії хронічного стресу = The dynamics of the morphofunctional changes of the offspring-rats’ pancreases and level of cytokinins resulting from an action of the chronic stress

Nikolayeva O., Pavlova E., Sirenko V., Kovaltsova M., Sulhdost I. Динаміка морфофункціональних зрушень підшлункової залози та рівень цитокинів у потомства щурів внаслідок дії хронічного стресу = The dynamics of the morphofunctional changes of the offspring-rats’ pancreases and level of cytokinins resulting from an action of the chronic stress. Journal of Education, Health and Sport. 2016;6(6):279-290. eISSN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.55416http://ojs.ukw.edu.pl/index.php/johs/article/view/3578 The journal has had 7 points in Ministry of Science and Higher Education parametric evaluation. Part B item 755 (23.12.2015).755 Journal of Education, Health and Sport eISSN 2391-8306 7© The Author (s) 2016;This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, PolandOpen Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium,provided the original author(s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License(http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited.This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted, non commercialuse, distribution and reproduction in any medium, provided the work is properly cited.The authors declare that there is no conflict of interests regarding the publication of this paper.Received: 05.05.2016. Revised 25.05.2016. Accepted: 10.06.2016. УДК 616.37–091.8–092.9:613.24/.25:613.65:612.015.11 ДИНАМІКА МОРФОФУНКЦІОНАЛЬНИХ ЗРУШЕНЬ ПІДШЛУНКОВОЇ ЗАЛОЗИ ТА РІВЕНЬ ЦИТОКИНІВ У ПОТОМСТВА ЩУРІВ ВНАСЛІДОК ДІЇ ХРОНІЧНОГО СТРЕСУ О. В. Ніколаєва, О. О. Павлова, В. А. Сіренко, М. В. Ковальцова, І. О. Сулхдост Харківський національний медичний університет. Харків. Україна  The Dynamics Of The Morphofunctional Changes Of The Offspring-Rats’ Pancreases and Level Of Cytokinins Resulting From An Action Of The Chronic Stress O. Nikolayeva, E. Pavlova, V. Sirenko, M. Kovaltsova, I. Sulhdost Kharkiv National Medical University, Kharkov, Ukraine Introduction. The pathology of the pancreas caused by the stress is an actual problem of medicine. The purpose of the study was describe of characteristics morphofunctional state of the pancreas of babe-rats’ and to analyzed pro-inflammatory and anti-inflammatory cytokines balance. Materials and Methods. We studied morphological changes of pancreas of offspring-rats’ using histological, cytochemical, cytomorphometric and biochemical methods. We studied immunological status using biochemical methods. We studied the level of interleukin-12 and interleukin-4 in the blood. The core group of mother-rats was exposed to chronic stress immobilization. The comparison group consisted of animals that led ordinary life. For the rats, the experiment was stopped immediately after the birth of offspring in compliance with the ethical principles. Results. Stress during pregnancy in rats affects the morphology and function of the pancreas in the offspring. Symptoms of morphofunctional disorders are obvious even in the pancreas of newborn rats. There are reduced acini and islets of Langerhans, immaturity parenchymal area, edema, fibrosis, degenerative changes in the nuclei and cytoplasm exocrine and endocrine cells, decrease morphofunctional state of the same part of pancreas cell, violation of geodynamics. Most of them not only saves up until they are two months of age, but has a negative trend of growth severity: reducing the relative amount of parenchymal acini area, number and area of the islets of Langerhans, the number of endocrine cells in them, apiaries lipomatosis stroma. We also noticed simultaneous launch of compensatory-adaptive processes in the endocrine pancreas in the form of hypertrophy of single islets of Langerhans. The rats in all groups are diagnosed as having identical tendencies of cytokines change; significant buildup of pro-inflammatory interleukin-12 and reduction of anti-inflammatory interleukin-4 which indicates predominant involvement in pathogenesis of violation of pancreas cell component of immune system. Conclusions. The results suggest that chronic stress of pregnant rats is a significant risk factor for future chronic pathology of the pancreas rats-offspring.Keywords: chronic stress immobilization, pancreas, rats, interleukin, experiment. ДИНАМИКА МОРФОФУНКЦИОНАЛЬНЫХ НАРУШЕНИЙ ПОДЖЕЛУДОЧНОЙ ЖЕЛЕЗЫ И УРОВЕНЬ ЦИТОКИНОВ У ПОТОМСТВА КРЫС ВСЛЕДСТВИЕ ДЕЙСТВИЯ ХРОНИЧЕСКОГО СТРЕССА О. В. Николаева, Е. А. Павлова, В. А. Сиренко, М. В. Ковальцова, И. А. Сулхдост Харьковский национальный медицинский университет, Харьков, Украина Проведено морфологическое и биохимическое исследование влияния хронического стресса матери на морфофункциональные особенности поджелудочной железы новорожденного, одномесячного и двухмесячного потомства. Обнаружено, что пренатальный стресс приводит к морфофункциональной перестройке поджелудочной железы крысиного потомства, с развитием стойких и прогрессирующих в динамике деструктивных изменений в ациноцитах и эндокриноцитах, к снижению морфофункциональной активности части клеточных элементов, к развитию гемодинамических нарушений у части животных. Выяснено, что у разновозрастного крысиного потомства наблюдается системный гуморальный ответ в виде дисбаланса цитокинов с преобладанием  маркерного цитокина Th1-лимфоцитов (интерлейкина-12), что свидетельствует о вовлечении в патогенезе повреждения поджелудочной железы клеточной цепи иммунитета. Установлено, что цитокиновый дисбаланс негативно влияет на внутриклеточный метаболизм панкреацитов, их экзокринную и эндокринную секреторную активность, и, вероятно, может еще больше усиливать повреждения поджелудочной железы у экспериментальных животных.          Ключевые слова: ациноциты, эндокриноциты, иммобилизация, интерлейкины, крысята, эксперимент

Вивчення параметрів гострої та підгострої токсичності препарату “Рибохін” на моделі коропа

The goal of the work was to study of acute and subacute toxicity parameters of “Rybokhin” biological product (AI – chloroquine refer to derivatives 4-aminohinolines) on the model of carp. This drug is effective in the treatment of diseases caused by parasitic Protozoa and Monogenea. Carp scales of two years old were used in experiments. To determine acute toxicity, the fish were prescribed with chloroquine (by AI) in doses of 100; 200; 300; 400; 500; 600; 800; 1000 mg/kg of live weight. Two experimental and control fish groups of 30 individuals each were formed to determine subacute toxicity of “Rybokhin”. Experimental groups of fish were prescribed with “Rybokhin” in a dose (by AI) of 50 mg/kg and 10 mg/kg for two consecutive days. Blood samples were collected from six fish species from each group for clinical and biochemical indicators after 48 hours, 7, 14, 21 and 28 days. The hemoglobin content, number of red blood cells and leukocytes blood were determined. The intensity of peroxide oxidation of lipids (PОL), catalase activity, level of total antioxidant capacity (TAC), total proteins, albumin, globulins and glucose, circulating immune complexes (CІC) and seromucoids concentration, level of enzymatic activity: aspartate transaminase (АSТ), alanine transaminase (АLТ), ά-amylase blood plasma were determined. According to the research results, indicators of acute toxicity for carp were determined, namely LD50 of chloroquine is 528.66 ± 68.01 mg/kg; LD16 – 224.512 mg/kg; LD84 – 832.81 mg/kg; LD100 – 984.89 mg/kg, which indicate that the drug is low-toxic to fish (belongs to the fourth group of toxicity). When administrating of 50.0 mg/kg of “Rybokhin” (by AI) twice a day, the most expressed metabolic changes in fish body were observed on 21 day after its last administration. Thus, the drug’s toxic impact is in proteinogram alteration, transamination processes and in decreasing of fish immune reactivity. It points to the prevalence of catalytic processes over anabolic. Metabolic alterations are obviously directed to the activation of detoxication processes with increased energy use in fish body after getting of higher dosage of the product. So, on 28 day of experiment, the major part of studied parameters retrieved to control level. It was found that when the product was administrated twice a day in the dosage 10.0 mg/kg (by AI), which is used for treatment of parasitic diseases, no reliable changes of clinical and biochemical indices were detected in fish blood during the experiment.Метою досліджень було визначити параметри гострої та підгострої токсичності препарату “Рибохін” (ДР – хлорохін, якій є похідною 4-амінохінолінів) на моделі коропа лускатого. Даний препарат є ефективним при лікуванні захворювань, спричинених паразитичними найпростішими (Protozoa) та моногенетичними присиcнями (Monogenea). У експериментах використовували коропа лускатого дволітнього віку. При визначенні гострої токсичності рибам задавали хлорохін (ДР) у дозах 100; 200; 300; 400; 500; 600; 800; 1000 мг/кг маси тіла. Для визначення підгострої токсичності препарату “Рибохін” було сформовано дві дослідні та контрольна групи риб по 30 особин у кожній. Рибі дослідних груп дві доби поспіль задавали препарат “Рибохін” у добовій дозі 50 мг/кг та 10 мг/кг маси тіла (за ДР). Через 48 год, 7, 14, 21 та 28 діб з метою клініко-біохімічних досліджень проводили відбір крові у шести особин риб з кожної групи. У крові визначали вміст гемоглобіну, кількість еритроцитів і лейкоцитів. У плазмі крові визначали інтенсивність процесів пероксидного окиснення ліпідів (ПОЛ), каталазну активність, рівень загальної антиокиснювальної активності (загальна АОА); вміст загальних протеїнів, альбуміну і глюкози; концентрацію циркулюючих імунних комплексів (ЦІК) і серомукоїдів; рівень ензиматичної активності: аспартатамінотрансферази (АсАТ), аланінамінотрансферази (АлАТ) і ά-амілази. За результатами досліджень визначено показники гострої токсичності для коропа: LD50 хлорохіну становить 528,66 ± 68,01 мг/кг; LD16 – 224,512 мг/кг; LD84 – 832,81 мг/кг; LD100 – 984,89 мг/кг маси тіла, які вказують, що препарат є малотоксичним для риб (належить до четвертої групи токсичності). Максимальну вираженість метаболічних змін в організмі риб за дворазового застосування препарату “Рибохін” в добовій дозі 50,0 мг/кг маси тіла (за ДР) виявляли на 21-шу добу після останнього задавання. Так, механізми токсичної дії препарату полягають у перебудовах в протеїнограмі і процесах переамінування та гальмуванні імунної реактивності в організмі риб, що вказує на превалювання катаболічних процесів над анаболічними. Метаболічні перебудови, очевидно, спрямовані на активацію процесів детоксикації з підвищенням енергетичних затрат в організмі риби внаслідок потрапляння підвищених доз препарату. Отже, на 28-му добу експерименту левова частка досліджених показників за значенням відновлювалась до контрольного рівня. Встановлено, що за дворазового введення препарату в добовій дозі 10,0 мг/кг маси тіла (за ДР), яка є лікувальною при боротьбі із паразитарними хворобами, у динаміці експерименту не виявляли достовірних змін клініко-біохімічних показників крові дослідних риб

Acceptor binding energies in GaN and AlN

We employ effective mass theory for degenerate hole-bands to calculate the acceptor binding energies for Be, Mg, Zn, Ca, C and Si substitutional acceptors in GaN and AlN. The calculations are performed through the 6$\times$6 Rashba-Sheka-Pikus and the Luttinger-Kohn matrix Hamiltonians for wurtzite (WZ) and zincblende (ZB) crystal phases, respectively. An analytic representation for the acceptor pseudopotential is used to introduce the specific nature of the impurity atoms. The energy shift due to polaron effects is also considered in this approach. The ionization energy estimates are in very good agreement with those reported experimentally in WZ-GaN. The binding energies for ZB-GaN acceptors are all predicted to be shallower than the corresponding impurities in the WZ phase. The binding energy dependence upon the crystal field splitting in WZ-GaN is analyzed. Ionization levels in AlN are found to have similar `shallow' values to those in GaN, but with some important differences, which depend on the band structure parameterizations, especially the value of crystal field splitting used.Comment: REVTEX file - 1 figur