90 research outputs found
Deuteron-Proton Elastic Scattering at Intermediate Energies
The deuteron-proton elastic scattering has been studied in the multiple
scattering expansion formalism. The essential attention has been given to such
relativistic problem as a deuteron wave function in a moving frame and
transformation of spin states due to Wigner rotation. Parameterization of the
nucleon-nucleon -matrix has been used to take the off-energy shell effects
into account. The vector, and tensor, , analyzing powers of the
deuteron have been calculated at two deuteron kinetic energies: 395 MeV and
1200 MeV. The obtained results are compared with the experimental data
Measurement of the tensor Ayy and vector Ay analyzing powers of the deuteron inelastic scattering off berillium at 5.0 GeV/c and 178 mr
Tensor Ayy and vector Ay analyzing powers in the inelastic scattering of
deuterons with the momentum of 5.0 GeV/c on beryllium at an angle of 178 mr in
the vicinity of the excitation of baryonic resonances with masses up to
1.8 GeV/c^2 have been measured. The Ayy data are in a good agreement with the
previous data obtained at 4.5 and 5.5 GeV/c. The results of the experiment are
compared with the predictions of the plane wave impulse approximation and
\omega-meson exchange models.Comment: 18 pages, 9 figure
Harmonisation of Pharmacopoeial Requirements for Identification of Closely Related Species in Herbal Medicinal Products
Global interest in herbal medicinal products is growing, thus increasing the demand for medicinal plant raw materials. However, the growth in sales of raw materials entails the risk of a wider spread of counterfeit and substandard medicinal products. The use of such products can lead to serious complications and even death. This brings to the forefront the studies aiming at identification and quality control of herbal drugs. In addition, the relevance of these studies stems from the need for harmonisation of test methods for identification of related plant species as acceptable foreign elements in herbal medicinal products. The aim of the study was to determine the most widely used methods for identification of closely related plant species and to analyse the possibility of aligning the requirements of Russian standards and foreign pharmacopoeial monographs. According to the analysis of identification requirements, the main test method for identification of related plant species is thin-layer chromatography; morphological and anatomical characteristics of plants are also used. Methodological approaches of the European Pharmacopoeia to identification of closely related species in herbal medicinal products have found application in updating compendial standards of the Russian Pharmacopoeia. Russian standards are harmonised with the requirements described in monographs of leading pharmacopoeias and provide for the detection of unacceptable impurities in herbal medicinal products by morphological, anatomical and chromatographic characteristics
Tensor Ayy and vector Ay analyzing powers in the H(d,d')X and ^{12}C(d,d')X reactons at initial deuteron momenta of 9 GeV/c in the region of baryonic resonances excitation
The angular dependence of the tensor Ayy and vector Ay analyzing powers in
the inelastic scattering of deuterons with a momentum of 9.0 GeV/c on hydrogen
and carbon have been measured. The range of measurements corresponds to the
baryonic resonance excitation with masses 2.2--2.6 GeV/c^2. The Ayy data being
in good agreement with the previous results demonstrate an approximate
scaling up to -1.5 (GeV/c)^2. The large values of A_y show a significant role
of the spin-dependent part of the elementary amplitude of the NN->NN* reaction.
The results of the experiment are compared with model predictions of the
plane-wave impulse approximation.Comment: 7 pages, 7 figures. submitted to Yad.Fi
Modern methods for identification and quantification of cardiac glycosides
Scientific relevance. Cardiac glycosides have been used in medicine for over two centuries. Current studies suggest that biologically active substances from this group can be used to treat not only heart conditions but also viral infections, cancers, and other diseases. Therefore, quality control methods for cardiac glycosides are becoming increasingly relevant.Aim. Based on a review of Russian and international quality standards, as well as up-to-date scientific data, this study aimed to identify promising methods for the identification and quantification of cardiac glycosides in herbal drugs and herbal medicinal products, as well as to evaluate the possibility of substituting physicochemical methods for biological methods.Discussion. The methods that are currently used to standardise cardiac glycosides are either not selective or require laboratory animals (biological test systems). According to a study of pharmacopoeial methods for the identification of cardiac glycosides in herbal drugs and herbal medicinal products, chemical identification tests and thin-layer chromatography continue to be relevant. Quantitative testing of herbal drugs and extracts uses biological and non-selective (spectrophotometry) methods, whereas chromatography is described only in general and individual monographs for herbal drug preparations containing individual cardiac glycosides and medicinal products containing these preparations. Upon analysing quality standards and scientific publications, the authors identified potentially promising methods for the quantification of cardiac glycosides in herbal drugs, herbal drug preparations, and herbal medicinal products, namely chromatographic methods.Conclusions. Reverse-phase high-performance liquid cjromatography (HPLC) with spectrophotometric detection is the most suitable method for pharmacopoeial analysis. The development of an HPLC-based analytical procedure to determine the cardiac glycoside content will provide an opportunity to advance from biological or non-selective methods to more ethical and selective up-to-date techniques
Differential Cross Section of DP-Elastic Scattering at Intermediate Energies
The deuteron-proton elastic scattering is studied in the multiple scattering
expansion formalism. The contributions of the one-nucleon-exchange, single- and
double scattering are taken into account. The Love and Franey parameterization
of the nucleon-nucleon -matrix is used, that gives an opportunity to include
the off-energy-shell effects into calculations. Differential cross sections are
considered at four energies, MeV. The obtained
results are compared with the experimental data
Polarization of Lambda^0 hyperons in nucleus-nucleus collisions at high energies
The measurement of Lambda^0 hyperons polarization in nucleus-nucleus
collisions is considered as one of possible tools to study the phase
transition. Fixed target and collider experiments are discussed for the case of
Lambda^0's production from Au-Au central collisions at \sqrt{s_{NN}} of several
GeV.Comment: 15 pages, 6 figure
Гармонизация фармакопейных требований при определении близкородственных видов в лекарственных средствах растительного происхождения
Global interest in herbal medicinal products is growing, thus increasing the demand for medicinal plant raw materials. However, the growth in sales of raw materials entails the risk of a wider spread of counterfeit and substandard medicinal products. The use of such products can lead to serious complications and even death. This brings to the forefront the studies aiming at identification and quality control of herbal drugs. In addition, the relevance of these studies stems from the need for harmonisation of test methods for identification of related plant species as acceptable foreign elements in herbal medicinal products. The aim of the study was to determine the most widely used methods for identification of closely related plant species and to analyse the possibility of aligning the requirements of Russian standards and foreign pharmacopoeial monographs. According to the analysis of identification requirements, the main test method for identification of related plant species is thin-layer chromatography; morphological and anatomical characteristics of plants are also used. Methodological approaches of the European Pharmacopoeia to identification of closely related species in herbal medicinal products have found application in updating compendial standards of the Russian Pharmacopoeia. Russian standards are harmonised with the requirements described in monographs of leading pharmacopoeias and provide for the detection of unacceptable impurities in herbal medicinal products by morphological, anatomical and chromatographic characteristics.Во всем мире растет интерес к лекарственным средствам растительного происхождения (ЛСРП), что вызывает увеличение спроса на лекарственное растительное сырье. Оборотной стороной роста объемов продаж лекарственного растительного сырья являются риски увеличения масштабов распространения фальсифицированных и недоброкачественных ЛСРП. Применение подобных средств может повлечь за собой развитие серьезных осложнений и даже летальный исход. Таким образом, увеличивается актуальность исследований с целью идентификации и контроля качества лекарственного растительного сырья. Актуальность проводимых исследований обусловлена также необходимостью гармонизации методов идентификации близкородственных видов как допустимых примесей в лекарственных средствах растительного происхождения. Цель работы — выявить наиболее часто используемые методы идентификации близкородственных видов растений и оценить возможность гармонизации национальных стандартов качества с требованиями монографий зарубежных фармакопей. В результате проведенного анализа показателей подлинности установлено, что основным методом идентификации примесей близкородственных видов является метод хроматографии в тонком слое сорбента. При оценке подлинности также используются морфолого-анатомические характеристики растений. Методические подходы идентификации близкородственных видов в лекарственных средствах растительного происхождения, используемые в Европейской фармакопее, нашли применение при актуализации фармакопейных стандартов Государственной фармакопеи Российской Федерации. Они гармонизированы с требованиями монографий ведущих зарубежных фармакопей и предусматривают обнаружение недопустимых примесей в лекарственных средствах растительного происхождения по морфолого-анатомическим и хроматографическим характеристикам
Variation in Tropical Reef Symbiont Metagenomes Defined by Secondary Metabolism
The complex evolution of secondary metabolism is important in biology, drug development, and synthetic biology. To examine this problem at a fine scale, we compared the genomes and chemistry of 24 strains of uncultivated cyanobacteria, Prochloron didemni, that live symbiotically with tropical ascidians and that produce natural products isolated from the animals. Although several animal species were obtained along a >5500 km transect of the Pacific Ocean, P. didemni strains are >97% identical across much of their genomes, with only a few exceptions concentrated in secondary metabolism. Secondary metabolic gene clusters were sporadically present or absent in identical genomic locations with no consistent pattern of co-occurrence. Discrete mutations were observed, leading to new chemicals that we isolated from animals. Functional cassettes encoding diverse chemicals are exchanged among a single population of symbiotic P. didemni that spans the tropical Pacific, providing the host animals with a varying arsenal of secondary metabolites
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