Impurity breakdown and terahertz luminescence in n-GaN epilayers under external electric field

We report on the observation and experimental studies of impurity breakdown and terahertz luminescence in n-GaN epilayers under external electric field. The terahertz electroluminescence is observed in a wide range of doping levels (at noncompensated donor density from 4.5×10[sup 16] to 3.4×10[sup 18] cm[sup −3]). Spectra of terahertz luminescence and photoconductivity are studied by means of Fourier transform spectrometry. Distinctive features of the spectra can be assigned to intracenter electron transitions between excited and ground states of silicon and oxygen donors and to hot electron transitions to the donor states.Peer reviewe

Исследование сорбции лекарственных веществ перфтораном

Objective: to estimate the perfluorane adsorption capacity of the drugs belonging to different pharmacological groups. Materials and methods. The binding of perfluorane to 50 drugs at concentrations of 12.5 to 100 ^M was studied in vitro using equilibrium dialysis. Results. Interactions of ligands with the particles of perfluorane emulsion were found to be of three types. Type 1 substances were characterized by negative affinity to perfluorane; type 2 ligands acted indifferently with the emulsion; type 3 compounds were reversibly adsorbed with the particles of the blood substitute by the affinity constants ( Kaff) of 104 M-1. Conclusion. The perfluorane adsorption capacity is ambiguous and seems to depend on the properties of ligands. Type 3 interactions, which may lead to an increase in blood adsorption capacity and change in the pharmacokinet-ics of drugs used in combination with perfluorane, appear to be the most important. Key words: perfluorane, binding, drugs, drug interactions.Цель исследования — оценка сорбционной способности перфторана в отношении лекарственных веществ, принадлежащих к различным фармакологическим группам. Материалы и методы. В экспериментах in vitro с помощью метода равновесного диализа исследована степень связывания с перфтораном 50 лекарственных веществ, взятых в концентрациях от 12,5 до 100 мкМ. Результаты. Выявлены три типа взаимодействия лигандов с частицами эмульсии перфторана. Вещества первого типа характеризовались негативной тропностью к перфторану; ли-ганды второго типа вели себя индифферентно по отношению к эмульсии; соединения третьего типа обратимо сорбировались частицами кровезаменителя с константами взаимодействия Kag порядка 104 М-1. Заключение. Сорбционная активность перфторана в отношении лекарственных веществ проявляется неоднозначно и, по-видимому, зависит от свойств лигандов. Наиболее значимыми представляются взаимодействия третьего типа, результатом которых может стать увеличение сорбционной емкости крови и изменение фармакокинетики лекарств, используемых совместно с перфтораном. Ключевые слова: перфторан, связывание, лекарственные вещества, лекарственные взаимодействия

The content of chromium, manganese, copper and zinc in plasma and red blood cells in mothers and their newborns with a threatened pregnancy in the anamnesis

Objective. To study the changes in concentration of transition metals — chrome, manganese, copper and zinc — in peripheral blood serum and erythrocytes of women in labor and their newborns with the history of threatened pregnancy. To study the cell-membrane permeability indices.Characteristics of children and research methods. The authors selected 97 couples of the full-term newborns and their mothers. The test group (Group 1) included 57 couples with threatened pregnancy. The control group (Group 2) included 40 conditionally healthy couples of mother and child. The concentrations of chemical elements were determined in plasma and red blood cells by inductively coupled plasma mass spectrometry (ICP-MS). There were two stages of statistical processing. Initially, there were determined the parameters with a reliable change in the concentration of elements in women with threatened pregnancy. Then, the scientists calculated the relation values between all parameters for each element.Results. We observed the increase in concentration of chrome, manganese and zinc in the women in labor with the threatened pregnancy as compared to healthy women in labor. At the same time, zinc and chrome take the most active part in compensatory mechanisms of preservation of pregnancy. We observed the increase in intracellular manganese against the background of its reduction in plasma in the newborns born from mothers with threatened pregnancy. At the same time, the authors found the difference in the functioning of the erythrocyte membrane in relation to copper in mothers and newborns

Productivity of non-traditional horticultural crops in Kirov region

Results of perennial study of 31 varieties of honeysuckle, 19 varieties of sea buckthorn, 13 elite plantlets of filbert, and 6 forms of quince on productivity and stability of fructification under conditions of Kirov region are presented in the article. The researches were shown sharp variations of productivity levels of non-traditional crops in dependence of weather conditions of year . Moreover, fructification of sea buckthorn suffered significant influence of damages with seabuckthorn fruit fly. As a result of investigation high-productive (1.43-2.82 kg/bush) honeysuckle varieties were selected: Slavyanka, Bogdana, Amphora, Viola, Nizhegorodskaya rannyaya, Morena, and Suvenir. Three varieties had high and stable productivity level: Suvenir, Viola, and Nizhegorodskaya rannyaya. Form 988-11 had good level of stable productivity. Study of productivity in 19 samples of sea buckthorn had shown its significant variability by years of researches from 0.39 (2007) up to 7.0 (2008) kg/plant. Grouping of investigated varieties on level of fructification allowed to select high productive (17/91, Kudrina, Dyujmovochka, Nizhegorodskij souvenir, 7-70-13-91) and productive (Zarevo, 24/91) samples. Four buckthorn varieties had stable fructification - Kudrina, Zarevo, 17/91, and 24/91. Perennial study of elite forms of filbert selected on earliness had shown possibility of obtaining of every-year yield of this crop under condition of northern border of its natural area. Forms 1-3-27, 3-12-27 were selected having high and stable productivity level as well as sample 1-2-21 with stable good level of fructification. Study of influence of level of quince plants' subfreezing on its productivity had shown an existence of middle negative relation between these two parameters (r = -0.66). Form 3-99 was selected on productivity. Sample 6-99 had middle stable productivity level

Analysis of ontogenetic spectra of populations of plants and lichens via ordinal regression

Ontogenetic spectra of plants and lichens tend to vary across the populations. This means that if several subsamples within a sample (or a population) were collected, then the subsamples would not be homogeneous. Consequently, the statistical analysis of the aggregated data would not be correct, which could potentially lead to false biological conclusions. In order to take into account the heterogeneity of the subsamples, we propose to use ordinal regression, which is a type of generalized linear regression. In this paper, we study the populations of cowberry Vaccinium vitis-idaea L. and epiphytic lichens Hypogymnia physodes (L.) Nyl. and Pseudevernia furfuracea (L.) Zopf. We obtain estimates for the proportions of between-sample variability in the total variability of the ontogenetic spectra of the populations.10 page(s

Application of principal component analysis for study of ontogenetic spectrums of populations

6 page(s

Correlation structure of bilateral traits

4 page(s