Morphometric Analysis of Hippocampal Pyramidal Neurons in situ and in Grafts Developing in the Anterior Eye Chambers of Young and Aged Wistar Rats

We performed a morphometric analysis of the somatic and nuclear areas in the pyramidal neurons of the hippocampal fields CA1 and CA3 in situ and in grafts developing for six weeks in the anterior eye chambers of young (3-to-9 wk.) and of aged (18-to-19.5 mos.) Wistar rats. The mean areas of the CA1 pyramidal somata and nuclei were significantly decreased in the aged animals in situ. The mean parameters of the CA3 pyramidal neurons were not changed, although their distribution was different (bimodal versus unimodal in the young animals). In both groups of recipients, the areas of CA1 neurons and of their nuclei were significantly larger in the grafted tissue than those found in situ. The areas of CA3 neurons did not show any difference in aged recipients and demonstrated only slight hypertrophy in young recipients. We concluded that the area sizes of the pyramidal cell bodies and nuclei in CA1 neurons are more sensitive than those of CA3 neurons to both aging and transplantation. The age of recipients did not significantly influence the growth and development of grafted pyramidal cells

Моделирование вольт-амперной характеристики мемристора TiN/HfO2/Pt при различной толщине токопроводящего канала

The operation of the TiN/HfO2/Pt bipolar memristor has been simulated by the finite elements method using the Maxwell steady state equations as a mathematical basis. The simulation provided knowledge of the effect of conductive filament thickness on the shape of the I-V curve. The conductive filament has been considered as the highly conductive Hf ion enriched HfOx phase (x < 2) whose structure is similar to a Magneli phase. In this work a mechanism has been developed describing the formation, growth and dissolution of the HfOx phase in bipolar mode of memristor operation which provides for oxygen vacancy flux control. The conductive filament has a cylindrical shape with the radius varying within 5–10 nm. An increase in the thickness of the conductive filament leads to an increase in the area of the hysteresis loop of the I-V curve due to an increase in the energy output during memristor operation. A model has been developed which allows quantitative calculations and hence can be used for the design of bipolar memristors and assessment of memristor heat loss during operation.Методом конечных элементов и с использованием в качестве математического базиса уравнений Максвелла в стационарном состоянии проведено моделирование работы биполярного мемристора TiN/HfO2/Pt, что позволило изучить влияние толщины токопроводящего канала на форму вольт-амперной характеристики. За токопроводящий канал принималась обогащенная ионами Hf фаза HfOx (x < 2), имеющая структуру фазы Магнели, и, соответственно, обладающая повышенной электропроводностью. Разработан механизм образования, роста и растворения фазы HfOx в условиях биполярного режима работы мемристора, который позволяет управлять потоками кислородных вакансий. Токопроводящий канал имел форму цилиндра с радиусом, варьируемым в пределах 5—10 нм. Показано, что с увеличением толщины канала увеличивается и площадь гистерезисных петель вольт-амперной характеристики, что связано с возрастающей энергетической нагрузкой при работе мемристора. Разработана модель, которая позволяет проводить количественные расчеты и, следовательно,  может быть использована при конструировании биполярных мемристоров для оценки тепловых потерь во время их работы.

Contradiction and change in state socialism

No abstract available

THERMAL MODELLING OF TERAHERTZ QUANTUM-CASCADE LASER BASED ON NANOHETEROSTRUCTURES GaAs/AlGaAs

This work presents the result of a simulation of thermal processes in a terahertz quantum cascade laser (THz QCL) based on GaAs/AlGaAs nanoheterostructure with a bimetal waveguide. A simplified model of THz QCL was built. Model simplifications of THz QCL were justified. The temperature distribution and maximum temperature values in the active region were obtained for different duty cycles and for various active region sizes with proportional heat generation change. Different types of bonding of the active region and substrate were simulated. According to the results a conclusion about the optimal duty cycle and frequency for the pulse mode were formulated. The time-to-stationary mode for different pulse width was calculated. The maximum temperature gradient in THz QCL was calculated

North Caucasian Federal District: Conditions and Strategic Reference Points of Development

The authors have carried out the analysis of the North Caucasian Federal District economy in a number of the directions: a general economic situation in the region, investment activity and investment appeal, the diagnostics of the budget stability and budget independence has been performed. They draw the conclusion that the economy of the district has a pronounced non-productive nature, its developed structure and disproportions interfere with forming the stable results and growth of the citizens’ welfare. There are no institutional conditions for the development, a lot of problems with uncoordinated migration flows and logistic disproportions in the region. In order to solve the mentioned problems the concept and the district’s development strategic reference points are offered in the article. One of them is the organization and enhancement of regional clusters. Besides, the forward monotowns dynamics, forming the cross-industry balance, increase in the capacity of the macroregion as a transport (transit) corridor and solving the problems of logistic disproportions through updating and creating the mainstream infrastructure, as well as implementation of a funding mechanism for infrastructure projects are important