Hexafluorosilicates with heterocyclic cations: physicochemical properties and pharmacological activity

Обсуждаются результаты изучения некоторых свойств и потенциальной биологической активности гексафторосиликатов с шести- и пятичленными гетероциклическими катионами с целью оценки возможности их использования в качестве кариеспротекторных агентов. Полученные значения рН для 0,001 М водных растворов гексафторосиликатов относительно консервативны к изменению природы катиона и находятся в области 2,95–3,35, что предполагает реализацию в растворах равновесий гидролиза с образованием фторид (гидродифторид) ионов и свободных гетероциклических оснований. Анализ потенциальной биологической активности последних с использованием программы PASS 11 Professional показал высокую вероятность стимуляции слюноотделения и иммуностимулирующей активности для большинства из изученных структур.Following the results of this study, hexafluorosilicates with heterocyclic cations could be used as potential caries-preventive agents. The most promising targets for further study may be salts with cations, that have a pronounced antibacterial activity

Evaluation of the biological activity of functionalized pyridines and dipyridines as caries-preventive agents potential components

Проведен компьютерный поиск структур производных пиридина и дипиридина с высокой вероятностью существования противовоспалительной активности, представляющих интерес в качестве компонентов «ониевых» гексафторосиликатов — перспективных кариеспротекторных агентов. Поиск структур осуществляли путем подбора азотсодержащего гетероциклического основания и функциональной группы, которая обусловливает проявление биологической активности. В качестве основания использовали пиридин, 2,2’-, 4,4’-дипиридин, 2,2’-, 4,4’-дипиридинкетон. Оценку потенциальной биологической активности полученных структур проводили с исполь- зованием программы PASS 11 Professional. Результаты компьютерного анализа показали, что среди структур, содержащих остаток уксусной кислоты, наибольшая вероятность наличия противовоспалительной активности у производных 2,2’-, 4,4’-дипиридинкетонов. Наличие остатка α-пропионовой кислоты в структуре молекулы в значительной степени повышает вероятность существования противовоспалительной активности, особенно среди производных пиридина и 2,2’-, 4,4’-дипиридинкетонов.The results of computer analysis showed that among the structures containing the residue of acetic acid greatest probability of having anti-inflammatory activity in derivatives 2,2’-, 4,4’- dipyridineketones. The presence of a residue α-propionic acid in the structure of the molecules greatly increases the probability of the existence of anti-inflammatory activity, especially among the pyridine derivatives and 2,2’-, 4,4’-dipyridineketones. Conclusions. Our data indicate a high probability of the existence of anti-inflammatory activity of pyridine derivatives and isomeric 2,2’-, 4,4’-dipyridine and 2,2’-, 4,4’-dipyridineketones. It is shown that the introduction of the second residue of acetic acid in the structure of the molecule and the location of propionic acid residue in the γ-position relative to the pyridine nitrogen atom greatly increases the likelihood of anti-inflammatory activity. The work opens up a promising direction in purposeful synthesis of new anti-inflammatory drugs and the ability to get on their basis hexafluorosilicates for use as a caries-preventive agents in dental practice

Charging Ultrasmall Tunnel Junctions in Electromagnetic Environment

We have investigated the quantum admittance of an ultrasmall tunnel junction with arbitrary tunneling strength under an electromagnetic environment. Using the functional integral approach a close analytical expression of the quantum admittance is derived for a general electromagnetic environment. We then consider a specific controllable environment where a resistance is connected in series with the tunneling junction, for which we derived the dc quantum conductance from the zero frequency limit of the imaginary part of the quantum admittance. For such electromagnetic environment the dc conductance has been investigated in recent experiments, and our numerical results agree quantitatively very well with the measurements. Our complete numerical results for the entire range of junction conductance and electromagnetic environmental conductance confirmed the few existing theoretical conclusions.Comment: 7 pages, 3 ps-figure

Study of the Power Beam Pattern of RATAN-600 During the Deep RZF Survey (1998-2003)

This paper proposes a method for constructing an experimental power beam pattern (PB) of RATAN-600 based on the sample of NVSS sources observed in the process of a deep sky survey near local zenith. The data obtained from observations of radio sources at wave 7.6 cm in nine bands of the survey (the 2002 and 2003 sets) are used to construct vertical PB of the telescope at rather large offsets from the central horizontal section of the PB (+/-36'). The experimental PBs obtained using different methods are compared and the root-mean-square deviations of the experimental PB from the corresponding computed PB are determined. The stability of the power beam pattern in its central part (+/-6') during the RATAN-600 Zenith Field (RZF) survey (1998-2003) and the accuracies of the fluxes of the sources observed within the framework of this survey and included into the RZF catalog are estimated.Comment: 15 pages, 17 figure

Induced pseudoscalar coupling of the proton weak interaction

The induced pseudoscalar coupling $g_p$ is the least well known of the weak coupling constants of the proton's charged--current interaction. Its size is dictated by chiral symmetry arguments, and its measurement represents an important test of quantum chromodynamics at low energies. During the past decade a large body of new data relevant to the coupling $g_p$ has been accumulated. This data includes measurements of radiative and non radiative muon capture on targets ranging from hydrogen and few--nucleon systems to complex nuclei. Herein the authors review the theoretical underpinnings of $g_p$, the experimental studies of $g_p$, and the procedures and uncertainties in extracting the coupling from data. Current puzzles are highlighted and future opportunities are discussed.Comment: 58 pages, Latex, Revtex4, prepared for Reviews of Modern Physic