Dielectric model of point charge defects in insulating paraelectric perovskites

Some point defects (i.e., oxygen vacancies) create deep trapping levels in the bandgap of the paraelectric phase ferroelectric crystals. Under applied DC field the traps release electrons via the Poole-Frenkel mechanism and become charged. The electric field of a point charge polarizes the crystal locally reducing its permittivity. In this paper a simple theory is proposed for calculating the DC field dependent apparent (measureable) permittivity of a paraelectric crystal with point charge defects. It is shown that the apparent permittivity of a paraelectric crystal may be sufficiently lower as compared with the defectless crystal. This reduction is in addition to the possible reduction of the apparent permittivity associated with the interfacial "dead" layers and strain

Сells of buccal epithelium charge state in children with lesions of the oral mucosa at the background of acute lymphoblastic leukemia in the dynamics of the treatment

To study the charge state of buccal epithelial cells (BEC) in children with lesions of the mouth mucous membrane at the background of acute lymphoblastic leukemia in the dynamics of the treatment. The charge state of BEC in 126 children with lesions of the oral mucosa at the background of acute lymphoblastic leukemia (ALBL) in different periods of its course in the dynamics of treatment has been studied. All the children were divided into two groups – the basic one (n=91) and the one of comparison (n= 35). Depending on acute lymphoblastic leukemia clinical stage all the children under examination were divided into three subgroups (the acute phase, remission, relapse). At the first acute period and at the relapse of ALBL the treatment-and-prophylactic complex including kvertsetin and polyphenol containing mucosal gel applications, the treatment of oral cavity mucosa with antimycotic agents, antiseptic with a mixture of alkaloid bisulfate with sanguinarine with chelerythrine and keratoplastic agent, probi-otic preparation INSIDE were used. At the period of remission polyphenol containing gel, kera-toplastic remedy and probiotic were administered. For the individual hygiene of mouth cavity alcohol-free lysozyme dentifrice water with anti-inflammatory effect was used. The children under study had a reduced level of BEC functional activity in comparison with norm in both groups of the patients. During treatment, there was an increase in the number of BEC moving nuclei and nuclei and plasmolemma amplitudes in the main group of children

Influence of tricalcium silicate on course of traumatic pulpitis

The use of Tricalcium Silicate (TS) as an odontotropic preparation makes it possible to create a hermetic crown restoration with a high degree of adhesion. However, the use of TS silicate by direct pulp capping remains disputable. The aim of this study was to determine the effects of TS on course of traumatic pulpitis by detection of morpho-functional peculiarities of changes in pulp tissue. We performed experimental investigation (on rabbits, males, aging three-month) for study of the morphofunctional changes of the pulp tissues with modeling of traumatic pulpitis and direct pulp capping with TS preparation (8 animals, investigated group) and calcium hydroxide (Calasept, NORDISKA DENTAL) preparation (8 animals, comparison group). After 2nd and 6th weeks tissues of tooth were fixed in 10% formalin with performing routine proceeding after decalcification and making histological slides which were investigated. Manifestations of protective adaptive mechanisms have been revealed in the form of inflammatory process two weeks after the injury in the pulp tissue with its resolution six weeks after performing of direct pulp capping with TS with replacement of necrotic area by connective tissue with their delimitation from viable pulp tissue against a background of intensive formation of capillaries. Morphometric study proved dynamical changes of vascular number cross-sections per 1 mm2 from 69.31±4.76 (2 weeks) to 47.38±4.12 (6 weeks) with 49.2±3.47 vascular density in intact group. Cellular density of odontoblasts as changed from 3.92±1.03 x103 per 1 mm2 (2 weeks) to 7.49±1.51 x103 per 1 mm2 (6 weeks) with 8.3±1.02 x103 per 1 mm2 cellular density in intact group. Thus it can be argued that the use of TS as a material for direct pulp capping promotes more active regeneration processes. Целью исследования явилось определение влияния трикальцийсиликата на течение травматического пульпита. Поставлен эксперимент на 3-месячных кроликахсамцах для изучения морфофункциональных изменений ткани пульпы с моделированием травматического пульпита и прямым покрытием пульпы трикальцийсиликатом (8 животных, исследуемая группа) и гидроксидом кальция (Calasept, NORDISKA DENTAL) (8 животных, группа сравнения). Спустя 2 и 6 недели ткани зуба фиксировали в 10% формалине и после декальцификации и рутинной проводки исследовали гистологические препараты. Спустя 2 недели после нанесения травмы в ткани пульпы обнаружены проявления защитно-приспособительных механизмов в виде воспалительного процесса с его разрешением, при котором наблюдается замещение зоны некроза соединительной тканью на фоне интенсивного новообразования капилляров, что характеризуется изменением плотности сосудов микроциркуляторного русла. Морфометрическое исследование показало динамические изменения количества сосудистых сечений с 69,31±4,76/мм2 (2 недели) до 47,38±4,12/мм2 (6 недель) при 49,2±3,47/мм2 в интактной группе. Плотность одонтобластов изменилась с 3,92±1,03×103/мм2 (2 недели) до 7,49±1,51×103/мм2 (6 недель) при 8,3±1,02×103/мм2 клеточной плотности в интактной группе. Таким образом, следует предположить, что использование трикальцийсиликата в качестве материала для прямого покрытия пульпы способствует более активным процессам регенерации

Comparative analysis of the effect of tricalcium silicate cement and mineral trioxide aggregate on the cellular composition of the pulp after the vital amputation in experimental animals.

The purpose of the study was to determine the effect of tricalcium silicate cement on the protective process of pulp in the treatment of reversible pulpitis. There was carried out an experiment on 3-month-old male rabbits to study  morphofunctional changes in the pulp tissue with modeling of reversible pulpitis followed by vital amputation with coating of the pulp with tricalcium silicate (8 animals, study group) and mineral trioxide aggregate (MTA) (8 animals, comparison group). In 2 and 6 weeks dental tissues were fixed by 10% formalin solution and after decalcification and done routine procedures, histological sections were made, stained with hematoxylin and eosin. After the application of tricalcium silicate cement in 2 weeks, the odontoblast density changed to 3.92±1.03×103/mm2 from 8.3±1.02×103/mm2 of cell density in the intact group. The number of neutrophils also plays a big role in the regeneration of inflamed pulp. Thus, in 2 weeks the number of neutrophils made up 6.39±2.61x102 per 1 mm2, which is 3 times less than after mineral trioxide aggregate usage – 19.49±2.85x102per 1 mm2. It was established that the processes of rheological disorders with impaired lymph circulation are replaced by the restoration of the cellular component. In such a way the proposed vital amputation was examined for reversible pulpitis and it revealed similar clinical and pathological effectiveness with a positive regenerative process with formation of a sufficient number of odontoblasts (7.98±1.51×103/mm2) for the subsequent formation of a hard tissue bridge, which consists of collagen fibers in the form of a frame. The main goal of vital amputation procedure is regeneration (proliferation) of the pulp with a short-term signs of alteration and exudation, which is provided by the choice of material for the pulp covering. Thus, after the vital amputation of the pulp, followed by the use of tricalcium silicate cement 6 weeks after, the number of neutrophils was 1.39±0.72x102per 1 mm2, which is 5 times less than after using mineral trioxide aggregate

Results of epidemiological survey and structural analysis of dental morbidity in children with various types of chronic pathology of the gastrointestinal tract

The anatomical and functional relationship between the gastrointestinal tract and its initial department - the organs of the oral cavity, causes the manifestation of severe dental pathology, especially in a chronic process, accompanied by impaired microbiocenosis and absorption and transport of nutrients in the small intestine. This affects the formation of teeth as highly mineralized organs, disrupts their structure, chemical composition and the formation of periodontal tissues, which leads, in turn, to the development of dental caries and chronic catarrhal gingivitis [1, 2]. In the complex of disorders it can be difficult to identify the proportion of each link of this system. Involvement in the pathological process of the organs functionally related to the intestine is accompanied by a violation of the activity of the latter and the possible development of severe changes in the entire digestive system. Therefore, along with the study of clinical manifestations that develop as a result of intestinal damage, it is important to identify the relationship between the oral cavity and diseases of the digestive organs, which allows us to clarify not only the pathogenesis of a number of pathological processes, but also to improve diagnostics, the choice of treatment and prevention methods [3]. In recent years, new information has been obtained that changes in the oral cavity are often a reflection of the patterns of pathogenesis of a number of pathological conditions and, first of all, from the digestive tract [4, 5]. Especially increased interest in the study of early symptoms of comorbidities, because pathological changes in the oral cavity often complicate the course of the underlying disease [4, 5]. Aim. To conduct an epidemiological survey and structural analysis of dental morbidity in children with various types of chronic pathology of the gastrointestinal tract. Materials and methods. In order to assess the pathological state of dental hard tissues and periodontal tissues, 345 children aged 7-15 years, who lived from birth in Dnipropetrovsk region, were examined

Keratinocytes as Depository of Ammonium-Inducible Glutamine Synthetase: Age- and Anatomy-Dependent Distribution in Human and Rat Skin

In inner organs, glutamine contributes to proliferation, detoxification and establishment of a mechanical barrier, i.e., functions essential for skin, as well. However, the age-dependent and regional peculiarities of distribution of glutamine synthetase (GS), an enzyme responsible for generation of glutamine, and factors regulating its enzymatic activity in mammalian skin remain undisclosed. To explore this, GS localization was investigated using immunohistochemistry and double-labeling of young and adult human and rat skin sections as well as skin cells in culture. In human and rat skin GS was almost completely co-localized with astrocyte-specific proteins (e.g. GFAP). While GS staining was pronounced in all layers of the epidermis of young human skin, staining was reduced and more differentiated among different layers with age. In stratum basale and in stratum spinosum GS was co-localized with the adherens junction component ß-catenin. Inhibition of, glycogen synthase kinase 3β in cultured keratinocytes and HaCaT cells, however, did not support a direct role of ß-catenin in regulation of GS. Enzymatic and reverse transcriptase polymerase chain reaction studies revealed an unusual mode of regulation of this enzyme in keratinocytes, i.e., GS activity, but not expression, was enhanced about 8–10 fold when the cells were exposed to ammonium ions. Prominent posttranscriptional up-regulation of GS activity in keratinocytes by ammonium ions in conjunction with widespread distribution of GS immunoreactivity throughout the epidermis allows considering the skin as a large reservoir of latent GS. Such a depository of glutamine-generating enzyme seems essential for continuous renewal of epidermal permeability barrier and during pathological processes accompanied by hyperammonemia

Measurement of the Cross Section Asymmetry of the Reaction gp-->pi0p in the Resonance Energy Region Eg = 0.5 - 1.1 GeV

The cross section asymmetry Sigma has been measured for the photoproduction of pi0-mesons off protons, using polarized photons in the energy range Eg = 0.5 - 1.1 GeV. The CM angular coverage is Theta = 85 - 125 deg with energy and angle steps of 25 MeV and 5 deg, respectively. The obtained Sigma data, which cover the second and third resonance regions, are compared with existing experimental data and recent phenomenological analyses. The influence of these measurements on such analyses is also considered

TGF-beta(2)- and H2O2-Induced Biological Changes in Optic Nerve Head Astrocytes Are Reduced by the Antioxidant Alpha-Lipoic Acid

Background/Aims: The goal of the present study was to determine whether transforming growth factor-beta(2) (TGF-beta(2))- and oxidative stress-induced cellular changes in cultured human optic nerve head (ONH) astrocytes could be reduced by pretreatment with the antioxidant alpha-lipoic acid (LA). Methods: Cultured ONH astrocytes were treated with 1.0 ng/ml TGF-beta(2) for 24 h or 200 mu M hydrogen peroxide (H2O2) for 1 h. Lipid peroxidation was measured by a decrease in cis-pari-naric acid fluorescence. Additionally, cells were pretreated with different concentrations of LA before TGF-beta 2 or H2O2 exposure. Expressions of the heat shock protein (Hsp) alpha B-crystallin and Hsp27, the extracellular matrix (ECM) component fibronectin and the ECM-modulating protein connective tissue growth factor (CTGF) were examined with immunohistochemistry and real-time PCR analysis. Results: Both TGF-beta(2) and H2O2 increased lipid peroxidation. Treatment of astrocytes with TGF-beta(2) and H2O2 upregulated the expression of alpha B-crystallin, Hsp27, fibronectin and CTGF. Pretreatment with different concentrations of LA reduced the TGF-beta(2)- and H2O2-stimulated gene expressions. Conclusion: We showed that TGF-beta(2)- and H2O2-stimulated gene expressions could be prevented by pretreatment with the antioxidant LA in cultured human ONH astrocytes. Therefore, it is tempting to speculate that the use of antioxidants could have protective effects in glaucomatous optic neuropathy. Copyright (C) 2012 S. Karger AG, Base

Multiplicity Structure of the Hadronic Final State in Diffractive Deep-Inelastic Scattering at HERA

The multiplicity structure of the hadronic system X produced in deep-inelastic processes at HERA of the type ep -> eXY, where Y is a hadronic system with mass M_Y< 1.6 GeV and where the squared momentum transfer at the pY vertex, t, is limited to |t|<1 GeV^2, is studied as a function of the invariant mass M_X of the system X. Results are presented on multiplicity distributions and multiplicity moments, rapidity spectra and forward-backward correlations in the centre-of-mass system of X. The data are compared to results in e+e- annihilation, fixed-target lepton-nucleon collisions, hadro-produced diffractive final states and to non-diffractive hadron-hadron collisions. The comparison suggests a production mechanism of virtual photon dissociation which involves a mixture of partonic states and a significant gluon content. The data are well described by a model, based on a QCD-Regge analysis of the diffractive structure function, which assumes a large hard gluonic component of the colourless exchange at low Q^2. A model with soft colour interactions is also successful.Comment: 22 pages, 4 figures, submitted to Eur. Phys. J., error in first submission - omitted bibliograph

Low Q^2 Jet Production at HERA and Virtual Photon Structure

The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the transverse energy and the pseudorapidity of the jets in the virtual photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3 < y < 0.6. The interpretation of the results in terms of the structure of the virtual photon is discussed. The data are best described by QCD calculations which include a partonic structure of the virtual photon that evolves with Q2.Comment: 20 pages, 5 Figure