Optically induced resonant tunneling of electrons in nanostructures.

We developed the theory of elastic electron tunneling through a potential barrier driven by a strong high-frequency electromagnetic field. It is demonstrated that the driven barrier can be considered as a stationary two-barrier potential which contains the quasi-stationary electron states confined between these two barriers. When the energy of an incident electron coincides with the energy of the quasi-stationary state, the driven barrier becomes fully transparent for the electron (the resonant tunneling). The developed theory is applied to describe electron transport through a quantum point contact irradiated by an electromagnetic wave.

All-optical control of excitons in semiconductor quantum wells.

Applying the Floquet theory, we developed the method to control excitonic properties of semiconductor quantum wells (QWs) by a high-frequency electromagnetic field. It is demonstrated, particularly, that the field induces the blue shift of exciton emission from the QWs and narrows width of the corresponding spectral line. As a consequence, the field strongly modifies optical properties of the QWs and, therefore, can be used to tune characteristics of the optoelectronic devices based on them.

Optically induced hybrid Bose-Fermi system in quantum wells with different charge carriers.

It is demonstrated theoretically that the circularly polarized irradiation of two-dimensional conducting systems can produce composite bosons consisting of two electrons with different effective masses (different charge carriers), which are stable due to the Fermi sea of conduction electrons. As a result, an optically induced mixture of paired electrons and normal conduction electrons (the hybrid Bose-Fermi system) appears. Elementary excitations in such a hybrid system are analyzed, and possible manifestations of the light-induced electron pairing are discussed for semiconductor quantum wells.

[COMPLEX ASSESSMENT OF ENVIRONMENTAL FACTORS AND POSTVACCINAL IMMUNE STATE].

This article was written on the base of the analysis of data of protocols of annual serological sturdies of the post-vaccination immunity status in indicator groups of populations, the analysis of samples of drinking water air and soil with the assessment of the socio-economic development of mono-towns and rural settlements. In the article there is reflected the comprehensive assessment of environmental factors and specific features of the formation of socio-economic conditions of rural communities and mono towns. There was performed a comparative assessment of the status of post-vaccination immunity to infections controlled by specific means of prevention, in different age groups in mono towns and rural settlements. There was established a dependence of the formation of post-vaccination immunity on the state of environmental factors.

[Effect of environmental factors on the formation of postvaccinal immunity].

In the present article there are considered the features of the formation of post-vaccination immunity in dependence on the level of anthropogenic load. The level of anthropogenic load on urban and rural areas on the base of the database of the Regional Foundation for Socio-hygienic monitoring of the Orenburg region has been determined. The assessment of the state of post-vaccination immunity was performed on average long-term indices in the indicator groups of children and adults. The distribution of the population throughout the strength of immunity to measles in dependence on area of residence has been determined. The relationship between the formation of post-vaccination immunity area of the residence has been established. In the population residing in urban areas the number of post- vaccination antibodies was significantly lower than that of the population in rural settlements.

[Features of formation of postvaccinal immunity in the population of one-company towns and rural settlements 1].

When assessing the risk of developing non carcinogenic effects, the authors calculated the summary danger indices for the Orenburg Region's population living in the urbanized and rural areas. The risk of developing harmful effects for children from monotowns and rural settlements was also determined. The findings lead to the conclusion that monotowns are the most unfavorable in terms of their risk of non carcinogenic effects. The next stage of the investigation was to study the strength of postvaccinal measles immunity, which revealed a close relation between the ecological state of a dwelling area and the formation of postvaccinal immunity.

[Surgical treatment of giant spinal neuromas].

Several cases of successful surgical treatment of giant spinal neuromas are reported in this paper. Benign nature of these tumors promotes radical resection. Localization of giant extravertebral tumor nodes in eloquent areas produces difficulties for total removal. In certain cases single approach is not sufficient for radical resection.

[Hygienic evaluation of transboundary pollution of the Ural River basin].

The anthropogenic pollution of the Ural River and its tributaries is the most important problem of the Ural-Caspian basin. Transboundary inflow from Kazakhstan to Russian is 30.9 km3/year. The border Ilek river pollution was hygienically evaluated and the contribution of pollution sources was ascertained, with the seasonal variations and hydrochemical background being kept in mind, from 2002 to 2007. The monitoring data on the content of priority pollutants of the surface waters of the basin of the Ilek River, a tributary of the Ural River, which come from the Republic of Kazakhstan, are given. Semiquantitative spectral estimation and the atomic absorption method were used to study the chemical composition of bottom sediments in the Ilek River and its tributaries. The magnitude and sources of influence of man-caused pollution on the quality of the river water were established.

[Hygienic evaluation of soil pollution in a South Ural agroindustrial region].

The results of soil monitoring the Orenburg Region (from 2003 to 2007) were comparatively analyzed. The structure of soil pollution with gross (vanadium, lead, nickel, chromium, cobalt, manganese, copper, zinc, tin, titanium, boron, molybdenum) and mobile (cobalt, manganese, copper, zinc, chromium, nickel) compounds was revealed. The Orenburg Region's soils experience an anthropogenic load, as evidenced by a two-fold soil clarke excess as described by A. P. Vinogradov. The highest soil pollution has been established in the eastern region that is most industrially developed. The presumable associations with possible pollution sources are outlined. Correlation analysis has revealed the inter-environmental distribution of trace elements in foodstuffs and the population's biological media.

[Comparative hygienic evaluation of the interenvironmental distribution of trace elements in the environment].

The paper presents the results of long-term monitoring of the content and interenvironmental distribution of the chemical elements Ni, Cd, Pb, Cr, Cu, Zn, Fe, and Mn over 1993-2007 in the environmental objects. The studies were made in the urbanized and rural areas of the Orenburg and Orsk-Troitsk industrial centers. General regularities were found in the quantitative distribution and priority relationships of the elements in the drinking water, in the atmosphere of residential areas (snow cover), in soil, foodstuffs, and children's biomedia.

[The specific features of clinical manifestations and surgical treatment of spastic and pain syndromes after injury to the vertebral column and spinal cord].

The purpose of the investigation was to study the clinical manifestations of spastic syndrome after injury to the vertebral column and spinal cord and to devise its surgical treatment policy. The investigation included 21 patients with significant spasticity or pain syndrome after severe injury to the vertebral column and spinal cord without any potential of motor recovery. All the patients were observed to have severe inferior paraplegia, cacesthesia following the radicular and conduction with total hypo- or anesthesia. Pain was rated, by using the visual analogue scale and the McGill questionnaire, spasticity was estimated by the Ashworth scale. The patients' motor activity was also evaluated. Bilateral rhizomyeolotomy of the dorsal root entry zone (DREZ) was performed in 10 patients with pain syndrome; posterior partial rhizidiotomy was made in 8 patients with spastic syndrome; 3 patients underwent epidural spinal cord stimulation. Groups with a preponderance of pain (47%) and spastic (53%) syndromes were identified. A clinically equal combination of spastic and pain components occurred rarely. Pain was maximally pronounced, neuropathic, metamerically radicular, in dermatomes from the level of injury. Leg spasticity was more marked and concurrent with contracture. The efficiency of lateral rhizomyelotomy of DREZ in the treatment of pain was 89% in the early period and 63% in the late (as long as 4 years) one. That of bilateral posterior partial rhizodiotomy in the treatment of spasticity was 75 and 75% in the early and late (as long as 2.5 years), respectively. Rhizomyelotomy of DREZ is a pathogenetically grounded and effective procedure when there is a preponderance of neuropathic metamerically radicular pain from the level of injury. Bilateral posterior partial rhizidiotomy is the method of choice in treating significant spasticity.

[Free radical oxidation in the assessment of health risk].

Aliovalent metals (d-metals, such as manganese, nickel, iron, copper, chromium, etc.) which are able to change the degree of oxidation, to activate free radical oxidative processes, and to initiate the development of the condition that is currently defined as oxidative stress soundly and which are diagnostic criteria in the prenosological assessment of health risks are prominent among other priority ambient air pollutants. The findings suggest that there is a direct relationship between the calculated indices characterizing the carcinogenic and noncarcinogenic effects, the risk of oxidative stress, the environmental availability of prooxidants, mainly d-elements (manganese, nickel, copper, zinc) and the actual values of an increase in the rate of lipid peroxidation, of a decrease in antioxidative activity, and of an elevation in the level of methemoglobin formation.

[Asymptomatic osteoma of the frontal sinus with intracranial invasion as a cause of post-traumatic pneumocephalus]. / Nemaia osteoma lobnoi pazukhi s vnutricherepnym rasprostraneniem kak prichina posttravmaticheskoi pnevmotsefalii.

A rare case of frontal sinus osteoma growing intracranially in a female of 38 is reported. The disease ran without any otorhinolaryngological or neurological symptoms until the sinus blunt injury followed by headaches resistant to analgetics and other neurological signs. Computed tomography discovered osteoma involving the cerebral cranium and pneumocephalus in the right cranial fossa. Management of patients with paranasal sinuses should account for possible intracranial complications and CT control of the tumor growth is very much desired.