Spin excitations of the correlated semiconductor FeSi probed by THz radiation

By direct measurements of the complex optical conductivity $\sigma(\nu)$ of FeSi we have discovered a broad absorption peak centered at frequency $\nu_{0}(4.2 K) \approx 32 cm^{-1}$ that develops at temperatures below 20 K. This feature is caused by spin-polaronic states formed in the middle of the gap in the electronic density of states. We observe the spin excitations between the electronic levels split by the exchange field of $H_{e}=34\pm 6 T$. Spin fluctuations are identified as the main factor determining the formation of the spin polarons and the rich magnetic phase diagram of FeSi.Comment: 5 pages, 4 figure

Formation of groundwater levels of drained lands in the natural and climatic conditions of the Novgorod region

Studies on the formation of groundwater levels have been carried out on open and closed drainage systems in the natural and climatic conditions of the Novgorod region for more than 30 years at 2 pilot production sites. On the first site there are 4 structures of closed drainage: shallow with a depth of 70 cm; medium-deep drainage (drainage depth 110 cm) with various options for filling the drainage trench-wood chips and sand-gravel mixture; two-tier drainage (drainage depth 110 and 60 cm). On the second site there are four open drainage structures: channels; hollows – without hydro-reclamation structures; with drainage along the bottom-tubular and strip-free. The average long-term data on groundwater regimes on experimental structures were obtained and conclusions were drawn that the average seasonal groundwater level formed by closed drainage systems is 18 cm lower compared to open drainage systems; the most favorable groundwater regime is formed by drainage systems of two-tier drainage. The dependences of groundwater levels formed during the most intense periods of operation of drainage systems (May – 1st decade of June) on the amount of precipitation for previous periods are analyzed. It was revealed that the closeness of the relationship between groundwater levels and the amount of precipitation in the open drainage variants is less close (r2 = 0.01-0.30) compared with the closed drainage variants (r2 = 0.02-0.54). The closest relationship on closed drainage systems is observed between the groundwater level of the third decade of May and precipitation for May: during this period, with an increase in precipitation by 1 mm, groundwater rises by 0.3 cm – in the variant with chip filling and by 0.6 cm – in the variants of shallow and two-tier drainage

EXPRESSION DENSITY OF RECEPTORS FOR IMMUNOREGULATORY MEDIATORS AS A MODULATORY COMPONENT OF BIOLOGICAL EFFECTS OF MEDIATORS UPON CELLS (PART 2)

The present review article summarizes the latest world scientific data on the role of receptors for immune mediators in regulating biological effects on the cells. For the main classes of immune regulators (interleukins, interferons, growth factors and tumor necrosis factors), the variants are presented for participation of receptors as components of cytokine/cell interaction, as proven by in vitro and in vivo studies. Ability of the receptors expression to modify characteristics and type of these interactions is shown. The data on participation of receptors for regulatory molecules in development of immune-mediated diseases of various genesis have been analyzed. It was demonstrated that the changes in the receptor expression are of great importance when evaluating functional response of the cells to the mediators and in development of pathological conditions. Current studies confirmed the data suggesting effects of receptor density upon the processes of proliferation and apoptosis, as well as metabolic processes that trigger development of autoimmune, oncological and dystrophic diseases. For all the considered classes of regulatory molecules, the change in the density of receptor expression is one of the key aspects in regulating functional activity of the cells. Thus, studying expression levels of receptors on the cell membrane is important in understanding pathogenesis, whereas changing expression level may be considered as a therapeutic target in the treatment of various diseases

Конвективный теплообмен и аэродинамическое сопротивление двух расположенных бок о бок труб в узком канале при различных числах Рейнольдса

We studied numerically and experimentally convective heat transfer and drag of two side-by-side tubes in different arrangements in the narrow channel at the Reynolds number ranging from 8000 to 40000 in comparison with circular tubes. The visualization results of the flow structure in the wake behind the arrangements of the investigated tubes are presented. It is shown that the thermal and hydraulic performance of side-by-side drop-shaped tubes is by a factor of 1.2–2 higher than that of circular tubes due to a lower drag of drop-shaped tubes.Проведено численное и экспериментальное исследование конвективного теплообмена и аэродинамического сопротивления двух расположенных бок о бок каплеобразных труб в различной компоновке, размещенных в узком канале в диапазоне чисел Рейнольдса от 8000 до 40000, в сравнении с трубами круглого сечения. Представлены результаты визуализации структуры течения в следе за компоновками исследуемых труб. Показано, что теплоаэродинамическая эффективность расположенных бок о бок капельных труб в 1,2–2 раза выше, чем у труб круглого сечения за счет более низкого аэродинамического сопротивления каплеобразных труб

Impaired Choroidal Blood Flow in Adolescents with Essential Arterial Hypertension

Arterial hypertension is a problem not only for adults, but also for children, but there are very few data on changes in the organ of vision under the influence of an elevated level of blood pressure in children.The aim of the work is to identify disturbances of the choroidal blood flow in children and adolescents with essential arterial hypertension.Methods. Fifty patients with essential arterial hypertension were examined. The age of patients ranged from 10 to 17 years, the duration of the disease ranged from 2 months to 8 years. All patients underwent color Doppler mapping of the orbital vessels, registration of the oscillatory potentials of the ERG.Results. It was revealed that increased arterial pressure causes retinal and choroidal ischemia, which is accompanied primarily by impaired blood flow in the orbital vessels and is reflected in a decrease in the amplitude and deformation of the peaks of the ERG oscillatory potentials.Conclusion. Hypertension causes and supports retinal and choroidal ischemia, which is accompanied primarily by impaired blood flow in the orbital vessels, functional depression of photoreceptors, ganglion cells and neuroglia of the retina, aggravating the identified changes as the experience of essential hypertension increases. A marker of chorioretinal ischemia is amplitude depression, a change in the shape of the teeth of the oscillatory potentials of the ERG, which indicates a decrease in the functional activity of the retinal ganglion complex.That is, these changes can be considered as a predictor of hypertensive angioretinopathy in children and adolescents with essential arterial hypertension

CLINICAL AND IMMUNOLOGICAL EFFECTIVENESS OF TREATMENT OF RAGWEED POLLINOSIS IN THE SAMARA REGION

Allergic rhinitis and bronchial asthma are widespread respiratory allergic diseases. In some territories of the Russian Federation, the dominant cause of pollinosis is ragweed. The aim of the study was to evaluate the clinical and immunological efficacy of ASIT with the allergen Ambrosia artemisiifolia in patients sensitized to Ambrosia trifida in the Samara region. Patients with proven sensitization to Ambrosia trifida was held immunotherapy with Ambrosia artemisiifolia allergoid preseason. After treatment, patients had a decrease in the severity of symptoms of allergic rhinitis according to VAS (p = 0.00001), a decrease in the need for medications (p = 0.0003), as well as the need for corticosteroids against the background of therapy from 34.6% to 0% (p = 0.00001). In 8% of cases, the result of treatment was good, in 69% satisfactory, in 23% unsatisfactory. In the control group, there were no changes in the severity of symptoms (p = 0.858). Also, in the control group, the need for medications remained unchanged and 14.3% of patients continued to use corticosteroids.After ASIT, there was a decrease in the level of IL-4 (p = 0.002), and a decrease in the ratio of IL-4/ IL-10 (p = 0.0063); at the same time, changes in the level of other cytokines (IL-10; IFNγ) were statistically insignificant (p > 0.05). Before treatment, the levels of IL-4/ IL-10 in both groups were comparable, and after treatment, the differences became statistically significant (p = 0.031). We did not get a statistically significant change in the level of IgG4 Amb a 1 or IgG4 Amb trifida. There was no correlation between the level of individual cytokines and the results of treatment. As a result of the conducted ASIT, positive clinical and immunological results were obtained. In most patients, the disease has acquired a controlled course. At the same time, the lack of excellent and low number of good results of ASIT is probably due to the intraspecific allergenic properties of ragweed