Light-emitting diodes with Ge(Si) nanoislands embedded in photonic crystals.

Room temperature lateral p+-i-n+light-emitting diodes (LEDs) with photonic crystals embedded in the i-region were fabricated on structures with Ge(Si) self-assembled islands and their optical properties were investigated. The use of preliminary amorphization and solid phase epitaxy of the implanted p+and n+contact regions made it possible to reduce the impurity activation temperature from 800 °Ð¡-1100 °Ð¡ to 600 °Ð¡, which corresponds to the growth temperature of Ge(Si) islands. This resulted in a significant reduction of the detrimental effect of the high-temperature annealing used for diode formation on the intensity and spectral position of the luminescence signal from the islands. It was shown that significant enhancement (more than an order of magnitude) of room temperature electroluminescence of Ge(Si) islands in the spectral range of 1.3-1.55µm can be achieved due to their interaction with different modes of the photonic crystals. The measured radiation power of the obtained diodes in the spectral range of 1.3-1.55µm exceeds 50 pW at a pump current of 8 mA, which is an order of magnitude higher than the previously achieved values for micro-LEDs with Ge(Si) nanoislands. The obtained results open up new possibilities for the realization of silicon-based light emitting devices operating at telecommunication wavelengths.

[Intraosseous metastasis of K27-mutant glioma]. / Vnutrikostnoe metastazirovanie K27-mutantnoi gliomy.

Glioma metastasis outside the central nervous system is a quite rare phenomenon. The disease in a young woman manifested itself as back pain and loss of vision in the left eye. Magnetic resonance imaging (MRI) revealed a tumor of the optic nerve; positron emission tomography showed multiple secondary bone changes. At the same time, MRI detected no signs of neoplasm in the midline brain structures (the brain stem and subcortical nuclei) and spinal cord. Two biopsies (superior iliac spine trephine biopsy and optic nerve tumor biopsy) were performed. There were similar histological tumors; the optic nerve tumor was found to have K27M mutation in the H3F3A gene, whereas the metastatic tumor lacked this mutation (possibly due to the quality and quantity of DNA isolated from the tumor cells). The interesting features of this case are the simultaneous detection of primary and metastatic tumors before receiving any treatment and the absence of the K27M mutation in the H3F3A gene in the metastasis.

[Multiple skull base defects: features of pathogenesis, diagnosis and treatment]. / Mnozhestvennye defekty osnovaniya cherepa: osobennosti patogeneza, diagnostiki i lecheniya.

OBJECTIVE: To determine the risk factors of multiple skull base defects, as well as features of diagnosis and treatment of this pathology. MATERIAL AND METHODS: A retrospective analysis included 39 patients who underwent surgery for nasal CSF leakage at the Burdenko Neurosurgical Center in 2000-2019. The study recruited patients with multiple simultant skull base defects. RESULTS: Traumatic defects were observed in 23 (59%) patients, spontaneous defects - in 16 (41%) cases. All patients underwent endoscopic endonasal closure of skull base defects with autografts. CONCLUSION: Multiple defects are more common in severe traumatic brain injury. The main risk factors of multiple spontaneous defects are female sex and overweight. Adequate diagnosis implies high-resolution CT (slice width 0.5-1 mm), as well as intraoperative control of all suspicious and «weak¼ areas. Endoscopic endonasal technique is effective and safe for multiple skull base defects (efficiency 97%).

Diagnostics possibilities of erythrocytes analysis by the method of laser interference microscopy.

The morphofunctional state of erythrocytes significantly changes by the onset and progression of various diseases, as well as in critical conditions, injuries, accompanied by severe tissue damage. This leads to a violation of microcirculation and has an effect on hemorheology in general. In connection with this, there is a need for the development of adequate methods for assessing the functional activity of erythrocytes. The aim of the work was to study the possibilities of laser interference microscopy in the analysis of the functional state of erythrocytes. The results allowed us to quantify the state of the phase height and phase diameter of erythrocytes. Analysis of the surface nanostructure gave a qualitative assessment of the functional activity of cells. The following patterns were revealed: the action of adrenaline causes the appearance of echinocytes with an increase in phase height and decrease phase diameter and the appearance of spicules on the surface of cells. The action of cortisol leads to a decrease in the phase height and the phase diameter with the appearance of numerous loosening of the structure of the cell surface. Moreover, the traditional method of analyzing the distribution of erythrocytes in a population by morphology (discocytes, stomatocytes, and degeneratively altered cell forms) did not reveal statistically significant differences. Thus, the results indicate that the interference microscopy method allows a qualitative assessment of the morphofunctional activity of native cells. This increases the information content of the analysis and leads to the objectification of data on the functional capabilities of erythrocytes.

The non-adiabatic exciton transfer in tetrathiafulvalene chains: a theoretical study of signal transmission in a molecular logic system.

Using an exciton as a carrier was examined as a possible solution to the problem of signal transmission between molecular logic gates. A tetrathiafulvalene chain was chosen as a model for a molecular logic system and its distinct logic states were described as excitons located at certain tetrathiafulvalene units. The parameters of the exciton transfer between the units of the chain were studied. The transfer rate between the two adjacent units was calculated using the Plotnikov-Bixon-Jortner theory basing on molecular parameters calculated using TD-DFT. The order of electronic states was studied at the MCQDPT and TD-DFT levels of theory. It was found that certain functional groups in the chain can make exciton transfer faster than its recombination. The exciton can effectively carry a signal through the chain, which in turn can be enlarged and modified.

[Transcranial microsurgical decompression of the optic canal in surgical treatment of meningiomas of the sellar region]. / Transkranial'naya mikrokhirurgicheskaya dekompressiya kanala zritel'nogo nerva v khirurgii meningiom khiazmal'no-sellyarnoi oblasti.

RATIONALE: When removing the meningiomas of the sellar region, there is always a risk of visual impairment for various reasons, in particular, as a result of traction damage to the optic nerve. Decompression of the optic canal increases nerve mobility during tumor manipulation. In cases of meningioma growing into the canal, its decompression often seems necessary. AIM: Evaluation of the effectiveness and risks of performing decompression of the optic canal. MATERIALS AND METHODS: The study included patients with meningiomas of the parasellar location, who underwent surgical treatment at the Burdenko Neurosurgical Center for the period from 2001 to 2017. They were divided into two groups - main and control. The main group consisted of 129 patients who underwent decompression of the optic nerve canals when the tumor was removed. The tumor matrix in this group was most often located in the region of the tuberum sellae, supradiaphragmally, in the region of the anterior clinoid process and the optic canal. In 31 cases, decompression was bilateral - during one operation and using one access in 27 patients; in 4 cases, the decompression of the second canal was delayed for 1.5-3 months after the first operation. 160 decompressions were performed by the intradural and 7 - by extradural methods. During intradural decompression, the roof of the optic canal was resected, and during extradural decompression, the lateral wall of the canal was trephined. The control group consisted of 308 patients who did not undergo canal decompression when the tumor was removed. It included meningiomas with a predominant location of the matrix in the area of the tuberclum and diaphragm of the sella. Tumors in both groups were removed according to the same principles (matrix coagulation, mainly the gradual removal of the tumor, the use of ultrasonic aspirator, a situational decision on the radicality of the operation, etc.). The main difference between operations in these two groups was only canal related algorithms (with or without its trepanation), as well as the probable prevalence of significant lateral tumor growth in cases with canal trepanation. Visual functions in the «primary¼ group were evaluated before and after operations with trepanation of the canal depending on various factors - the initial state of vision and the radicality of the tumor excision, including removal from the canal. The differences in the postoperative dynamics of vision in the main and control groups were studied. The primary data processing was carried out using the program MSExcel. Secondary statistical processing was carried out using the program Statistica. To assess the statistical significance of differences in the results obtained in the compared patient groups, the Chi-square test was used, and in the case of small groups - the exact Fisher test was applied. RESULTS: In the main group postoperative vision improvement of varying degrees on the side of trepanation was registered in 36.9% (59 out of 160) cases, no vision changes were found in 36.9% (59 out of 160), and in 26,2% (42 out of 160) the eyesight deteriorated. If preserving vision is attributed to a satisfactory result, then in general the results of these operations should be considered good. A comparative study of the results of removal of meningiomas with trepanation of the canals (main group) or without it (control group) was carried out among patients with the most critical vision situation (visual acuity 0.1 and below, up to only light perception). These groups are comparable in the number of observations - 62 and 73 respectively. The predominance of cases with improved vision in the main group compared with the control group (50.0% versus 38.36%) and a lower incidence of vision impairment (22.58% versus 34.25%) were found. However, the revealed differences are statistically unreliable and make it possible for us to talk only about the trend. The complications associated with trepanation of the canal include mechanical damage to the nerve by the drill. In our series of observations, there was only 1 case of abrasion of the nerve surface with the burr, which did not lead to a significant visual impairment. With the intradural method of trepanation in the area of the medial wall of the canal, the sphenoid sinus may open (in our series, in 34 cases out of 160 trepanations). Immediately closure of these defects was performed by various auto- and allomaterials in various combinations (pericranium, fascia, muscle fragment, hemostatic materials, and fibrin-thrombin glue). A true complication - CSF rhinorrhea liquorrhea developed in only one case, which required transnasal plastic surgery of the CSF fistula using a mucoperiostal flap. CONCLUSIONS: 1. Trepanation of the optic canal in cases of meningiomas of parasellar localization is a relatively safe procedure in the hands of a trained neurosurgeon and does not worsen the results of operations compared with the excision of the same tumors without trepanation of the canal. 2. The literature data and the results of our study make it possible to consider the decompression of the optic canal as an optional, but in many cases, useful option that facilitates the transcranial removal of some meningiomas of the sellar region.

[The evaluation of genotoxic effects in buccal epithelium under disorders of adaption status of organism.]

The cyto-morphologic analysis of buccal epithelium is one of technique of evaluation of adaptation status of organism and xenogeneic intoxication. The analysis of reactivity of cells of buccal epithelium is used to obtain information concerning genetic alterations in human cells that is extremely important for proper decision making related to issues of population health protection. The smoking results in manifestation of tension of adaptation mechanisms and significant increasing of risk of development cytogenetic disorders in cells of buccal epithelium of oral cavity. The study was carried out concerning morphology of buccal epithelial cells of smoking youths. The cytogram demonstrated a reliable decreasing of number of normal cells and increasing of percentage of cells with various cytogenetic alterations. The cells with micro-nuclei are observed twice more often that can be considered as an integral indicator of genetic disorders in inter phase. In smokers, among cells with signs of completion of nucleus destruction the cells with karyorrhexis are registered reliably more often. The results of micro-nucleus test are an unfavorable prognostic indication testifying high degree of genotoxicity of tobacco smoke and meaning a disorder of cytogenetic homeostasis and decreasing of adaptation reserve of organism.

[Epidemiology and prophylaxis of varicella in military units].

Epidemiology and prophylaxis of varicella in military units. Topical issues in military units varicella epidemiology and prevention, as one of the most important infections, potentially controlled by means of immunization. As a result of the retrospective epidemiological analysis of the incidence of varicella personnel- in one of the military districts found that the risk category for the disease are conscripts from the young recruits. The main riskfactors for introduction and spread of the infection: violation of statutory requirements to placement and life conditions of young recruits, delays in army of observation in epidemic outbreaks of varicella. The connection of the skid in a military collective agents of varicella with disabilities in the diagnostic work of the medical service and the organization of sanitary and anti-epidemic regime in. infectious wards of military hospitals. The possibilities of improving the selective immunization against varicella soldiers of the young recruits.

[Ways of improvement of military epidemiology as a diagnosis and prophylaxis branch of military medicine].

Ways of improvement of military epidemiology as a diagnosis and prophylaxis branch of military medicine. The prospects of development of epidemiological science, training systems and improvement of practice in preventive medicine based on the integration process are considered. The authors emphasize a final recognition of epidemiology as a single diagnostic and preventive discipline the subjects of which are manifestations of epidemic diseases regardless aetiology. An integration of specialists in prophylaxis requires correction of the system of military-medical education and improvement of preventive medical support subsystem of (naval forces). The prospects of inclusion in the educational and scientific processes of the epidemiology of non-communicable diseases, improve the interaction of different structures of military medical services in the field of infectious disease prevention personnel.

[Orbitozygomatic approaches to skull base tumors spreading into the orbit, paranasal sinuses, nasal cavity, and pterygopalatine and infratemporal fossae].

The paper analyzes application of orbitozygomatic approaches at the Department of Skull Base and Craniofacial Surgery of the Burdenko Neurosurgical Institute for a 14-year period. During this time, 723 patients were operated on using the orbitozygomatic approach, which has become the workhorse of surgery for skull base tumors spreading into the orbit, paranasal sinuses, and pterygopalatine and infratemporal fossae. The authors describe seven major modifications of the orbitozygomatic approach that they have used in their practice.

[Orbitozygomatic approaches to the skull base].

The paper is written in the lecture format and dedicated to one of the main basal approaches, the orbitozygomatic approach, that has been widely used by neurosurgeons for several decades. The authors describe the historical background of the approach development and the surgical technique features and also analyze the published data about application of the orbitozygomatic approach in surgery for skull base tumors and cerebral aneurysms.

[Life quality of patients with benign tumors of the anterior and middle part of the skull base after surgery and during follow-up].

The results of surgical and combination therapy of 302 patients with benign tumors of the anterior and middle regions of the skull base with allowance for the functional outcomes (immediately after surgery and during the catamnestic follow-up) are reported. The Karnofsky and Rankin scales and the Anterior Skull Base Questionnaire (ASBQ) were used for the analysis. Radical tumor resection, as compared to partial resection, reduces the quality of life in the early postoperative period but increases it in future; the use of radiation therapy in combination treatment for patients with radically inoperable tumors does not worsen their quality of life in the late postoperative period.

X-ray absorption near-edge structure anomalous behaviour in structures with buried layers containing silicon nanocrystals.

Substructure and phase composition of silicon suboxide films containing silicon nanocrystals and implanted with carbon have been investigated by means of the X-ray absorption near-edge structure technique with the use of synchrotron radiation. It is shown that formation of silicon nanocrystals in the films' depth (more than 60 nm) and their following transformation into silicon carbide nanocrystals leads to abnormal behaviour of the X-ray absorption spectra in the elementary silicon absorption-edge energy region (100-104 eV) or in the silicon oxide absorption-edge energy region (104-110 eV). This abnormal behaviour is connected to X-ray elastic backscattering on silicon or silicon carbide nanocrystals located in the silicon oxide films depth.

Search for solar axions by the CERN axion solar telescope with 3He buffer gas: closing the hot dark matter gap.

The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the search range 0.64 eV ≲ ma ≲ 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of gaγ ≲ 3.3 × 10(-10) GeV(-1) at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of gaγ, for example by the currently discussed next generation helioscope International AXion Observatory.

[Optic nerve decompression in treatment of neoplasms involving optic canal].

Neoplasms extending to the optic canal is a diverse group of more than 15 histological types. Elimination of the optic nerve compression is crucial for favorable visual outcome. Material and method. We perform a prospective analysis of 97 patients with different neoplasms with involvement of the optic canal in whom surgery was performed in neurooncological department of Burdenko Neurosurgical Institute during the period from 2010 to 2012. Extent of resection and recurrence rates were determined by pre- and postoperative CT and MRI studies. Results. 97 patients (78 women and 19 men) were involved in the study. Mean age was 49,4 years. Patients were followed for mean of 15.9 months (1-36 month). Total resection was achieved in 54 (55.6%) patients, gross-total resection in 40 (41,2%), partial resection in 3 (3.2%). Underwent postoperative stereotactic radiation therapy 30 patients. There was no recurrence in a series of observations. 4 patients showed extension into both optic canals. Visual disturbances were the main presenting symptoms in 50 (51.5%) patients. 10 (10.3%) patients had normal visual status initially. Visual improvement after surgery was seen in (37%) of 87 patients with visual disturbances. Visual deterioration occurred in 17 (19%) patients. Transient visual deterioration occurred in 1 patient with recovery to the base level over time. The visual outcome was affected by the duration of the symptoms before surgery and the stage of visual disturbances according to the eyeground changes. Conclusions. Involvement of the optic canal is a common phenomenon in craniofacial tumors. Neoplasms extending to the optic canal is a diverse group of both the localization and histology. Decompression of the optic nerves is a crucial step in the surgical management of this neoplasms to optimize visual recovery and prevent tumor recurrence.

[Surgery of skull base tumors extending into the orbit, paranasal sinuses, nasal cavity, pterygopalatine and infratemporal fossas: treatment principles in certain types of tumors].

Following the paper focused on surgery of skull base tumors invading the orbit, paranasal sinuses, nasal cavities, pterygopalatine and infratemporal fossae, the authors discuss particular issues of surgical treatment of the most common craniofacial mass lesions, including meningiomas, juvenile angiofibromas, trigeminal nerve tumors, chondroid tumors, and others.

[Diphtheria in the military forces: lessons and current status of prophylaxis, prospects of epidemiological control process].

We analyzed the epidemiological situation of diphtheria in the world and in Russia and experience of mass vaccination of military personnel and civil population with diphtheria toxoid for the last 50 years. Early diagnosis of diphtheria in military personnel has a prognostic value. Authors described the peculiarities of epidemiological process of diphtheria in military personnel in 80-90 years of 20th century and organizational aspects of mass vaccination with diphtheria toxoid. Authors analyzed current problems of epidemiology and prophylaxis of diphtheria in military personnel and civil population and possible developments. According to long-term prognosis authors mentioned the increase of morbidity and came to conclusion that it is necessary enhance the epidemiological surveillance. Authors presented prospect ways of improvement of vaccination and rational approaches to immunization of military personnel under positive long-term epidemiological situation.

Using non-adiabatic excitation transfer for signal transmission between molecular logic gates.

Molecular logic gates (MLGs) are molecules which perform logic operations. They can potentially be used as building blocks for nano-sized computational devices. However, their physical and functional integration is a difficult task which remains to be solved. The problem lies in the field of signal exchange between the gates within the system. We propose using non-adiabatic excitation transfer between the gates to address this problem while absorption and fluorescence are left to communicate with external devices. Excitation transfer was studied using the modified Bixon-Jortner-Plotnikov theory with the example of the 3H-thioxanthene-TTF-dibenzo-BODIPY covalently linked triad. Several designs of the molecule were studied in a vacuum and cyclohexane. It was found that the molecular logic system has to be planar and rigid to isolate radiative interfaces from other gates. Functioning of these gates is based on dark πσ*-states in contrast to bright ππ*-states of radiative interfaces. There are no fundamental differences between ππ* → πσ* and ππ* → ππ* transitions for cases when an exciton hops from one gate to another. The rates of such transitions depend only on an energy gap between states and the distance between gates. The circuit is highly sensitive to the choice of solvent which could rearrange its state structure thereby altering its behavior. According to the obtained results, non-adiabatic transfer can be considered as one of the possible ways for transmitting a signal between MLGs.

[Tumors of the skull base, extending into the orbit, paranasal sinuses, nasal cavity, pterygopalatine and infratemporal fossa].

The first of two papers focusing on surgery of skull base tumors invading orbit, sinonasal cavities, pterygopalatine and infratemporal fossae the authors described foundation and development of craniofacial oncology as a new discipline in skull base surgery, modern approaches to diagnostic evaluation of craniofacial mass lesions and basic principles of surgical management.

[Modern combined technologies for the rehabilitation of the patients presenting with arterial hypertension and its prevention].

The present review describes the modern methods for the combined treatment and rehabilitation of the patients presenting with arterial hypertension and their influence on the key pathogenetic components of this condition in accordance with the currently accepted theories of its origin and evolution. The discovery of specific molecular and cellular mechanisms of the therapeutic action of certain factors that reflect peculiar and unique character of their inherent physical energy provided a basis for the development of highly effective methods for the treatment and prevention of arterial hypertension and rehabilitation of the patients suffering this disease. The most comprehensive clinical effect is produced by the application of scientifically sound therapeutic systems; exclusion of certain therapeutic physical factors from these modalities results in s significant reduction of their curative effectiveness.