Universality of finite-size corrections to the number of critical percolation clusters

Monte-Carlo simulations on a variety of 2d percolating systems at criticality suggest that the excess number of clusters in finite systems over the bulk value of nc is a universal quantity, dependent upon the system shape but independent of the lattice and percolation type. Values of nc are found to high accuracy, and for bond percolation confirm the theoretical predictions of Temperley and Lieb, and Baxter, Temperley, and Ashley, which we have evaluated explicitly in terms of simple algebraic numbers. Predictions for the fluctuations are also verified for the first time.Comment: 13 pages, 2 figs., Latex, submitted to Phys. Rev. Let

Clinical Justification for Preliminary Thermal Exposure to Composite in the Treatment of Caries: Randomized Clinical Trial

Background. Polymer composites have good aesthetic characteristics and pronounced physicochemical properties, as compared to traditional restorative materials such as amalgam. However, the polymerization reaction of composite material containing bismethacrylate group commonly used in clinical practice is always accompanied by a different degree of volumetric shrinkage (2.7%~7.1%). The resulting stress can lead to adhesion failure and some other unfavorable clinical consequences, such as enamel destruction, microcracking of composite material and formation of microleakage between composite and tooth cavity wall, which can result in recurrent caries and postoperative sensitivity, thereby affecting the long-term effect of restoration. Therefore, studying the effect of preheating on composite restoration is important for its clinical application. Objective. To improve the effectiveness of treatment of patients with dental caries by improving the physicochemical properties of composite restorations.Methods. A randomized clinical trial enrolled 180 patients aged 18 to 45 years, diagnosed with dentin caries class I, according to Black (K02.1 in ICD). The study was conducted in the Dental Clinic of Kuban State Medical University, Russia. 180 composite restorations were performed in the treatment of dentin caries of molars. Patients were randomized into 2 groups): the control group — 90 patients and the main group — 90 patients. The control and main groups, in turn, were divided into three subgroups, depending on the composite used — Estelite Sigma Quick (Tokuyama Dental, Japan), Filtek Bulk Fill Posterior Restorative (3M Espe, USA) and DentLight (VladMiVa, Russia). Each subgroup consisted of 30 patients. In the control group, the classical method of filling with a composite material at “room temperature” was applied. In the main group, a composite heating conditioner “Ena Heat” (Micerium, Italy) was used to heat the composite to 55 °C before adapting the material in the formed cavity with subsequent photopolymerization. The quality of composite restorations within the clinical study was evaluated using the modified Ryge criterion immediately after treatment and after 6, 12, 18, 24 months. Statistical processing of the obtained data was carried out by means of one-factor analysis of variance using the GraphPadPrism 9 program (GraphPad Software, USA).Results. The duration of the clinical study comprised 24 months. The study revealed a statistically significant decrease in the quality of marginal fit of composite restorations (according to the Ryge score) by 20.1% (p = 0.0001) in the control group and by 5.7% (p = 0.0328) in the main group.  At the same time, no statistically significant changes in Ryge scores were reported in the subgroups of composite materials of the main group (pF = 0.9480, pE = 0.1837, pD = 0.2529). As a result of the study, an optimal time algorithm (7 seconds) for using a special furnace for preheating the composite before sealing with subsequent photopolymerization was obtained.Conclusion. The study revealed a statistically significant positive effect of the proposed algorithm for working with a heated composite on the quality of marginal fit in the long term after treatment in comparison with the classical method of working with a composite at “room temperature”

A Gauge-Gravity Relation in the One-loop Effective Action

We identify an unusual new gauge-gravity relation: the one-loop effective action for a massive spinor in 2n dimensional AdS space is expressed in terms of precisely the same function [a certain multiple gamma function] as the one-loop effective action for a massive charged scalar in 4n dimensions in a maximally symmetric background electromagnetic field [one for which the eigenvalues of F_{\mu\nu} are maximally degenerate, corresponding in 4 dimensions to a self-dual field, equivalently to a field of definite helicity], subject to the identification F^2 \Lambda, where \Lambda is the gravitational curvature. Since these effective actions generate the low energy limit of all one-loop multi-leg graviton or gauge amplitudes, this implies a nontrivial gauge-gravity relation at the non-perturbative level and at the amplitude level.Comment: 6 page

Matrix model eigenvalue integrals and twist fields in the su(2)-WZW model

We propose a formula for the eigenvalue integral of the hermitian one matrix model with infinite well potential in terms of dressed twist fields of the su(2) level one WZW model. The expression holds for arbitrary matrix size n, and provides a suggestive interpretation for the monodromy properties of the matrix model correlators at finite n, as well as in the 1/n-expansion.Comment: 27 pages, 4 figures; v2: typos corrected, reference added, version to be published in JHE

Структура и функции ароматазы и ее нестероидные ингибиторы

The analysis of the structure and function of aromatase (SYP19) - enzyme from the family of cytochrome P-450 that catalyzes the aromatization of six-membered ring A of the steroidal skeleton, namely transformation of androgens into estrogens peripheral and tumor tissues in the body, has been performed, and data in its non-steroidal inhibitors have been summarized.Проведен анализ структуры и функции ароматазы (СYP19) - фермента семейства цитохромов Р-450, кодируемого расположенным на коротком плече 15-й хромосомы (локус 15q21) геном CYP19A1, катализирующего ароматизацию шестичленного цикла А стероидного скелета и обуславливающего метаболизм стероидных гормонов, а именно трансформацию андрогенов в эстрогены периферическими и опухолевыми тканями организма. Обобщены данные по ее нестероидным ингибиторам. Обсуждены особенности первичной и пространственной структуры СYP19, обуславливающие взаимодействие с мембраной клетки и субстратом, обеспечивающие транспорт последнего между липидным бислоем мембраны и активным центром фермента. Показано, что наиболее эффективными ингибиторами СYP19 в настоящее время являются соединения, содержащие в составе молекулы азольные и азиновые гетероциклические фрагменты

Получение и анти-ВИЧ активность β-галактозилсфингозина

Β-Galactosylsphingosine a potential anti-HIV agent, has been prepared from pig brain cerebrosides and tested for antiviral activity. HIV-inhibitory properties of this compound, predicted previously by molecular modeling, have been confirmed. Consequently, the glycolipid obtained is considered as a promising basic structure for designing its more efficient derivatives.На основе цереброзидов, выделенных из мозга свиньи, получен гликолипид β-галактозилсфингозин - потенциальный анти-ВИЧ-агент - и проведено его тестирование на противовирусную активность, которое подтвердило ВИЧ-ингибирующие свойства соединения, предсказанные ранее методами молекулярного моделирования. В связи с этим полученный гликолипид рассматривается как перспективная базовая структура для создания его более эффективных модифицированных форм

Dexmedetomidine is neuroprotective in an in vitro model for traumatic brain injury

<p>Abstract</p> <p>Background</p> <p>The α₂-adrenoreceptor agonist dexmedetomidine is known to provide neuroprotection under ischemic conditions. In this study we investigated whether dexmedetomidine has a protective effect in an <it>in vitro </it>model for traumatic brain injury.</p> <p>Methods</p> <p>Organotypic hippocampal slice cultures were subjected to a focal mechanical trauma and then exposed to varying concentrations of dexmedetomidine. After 72 h cell injury was assessed using propidium iodide. In addition, the effects of delayed dexmedetomidine application, of hypothermia and canonical signalling pathway inhibitors were examined.</p> <p>Results</p> <p>Dexmedetomidine showed a protective effect on traumatically injured hippocampal cells with a maximum effect at a dosage of 1 μM. This effect was partially reversed by the simultaneous administration of the ERK inhibitor PD98059.</p> <p>Conclusion</p> <p>In this TBI model dexmedetomidine had a significant neuroprotective effect. Our results indicate that activation of ERK might be involved in mediating this effect.</p