[Application of narrow-band optical radiation with a wavelength of 650 nm in complex treatment of children with developmental speech delay]. / Primenenie uzkopolosnogo opticheskogo izlucheniya s dlinoi volny 650 nm v kompleksnom lechenii detei s zaderzhkoi rechevogo razvitiya.

OBJECTIVE: To substantiate the use of photochromotherapy (narrow-band optical radiation with an average wavelength of 650 nm) in the complex treatment of children with developmental speech delay on the type of general speech underdevelopment (GSU) of I and II degree. MATERIAL AND METHODS: A number of children equal 70 aged from 4 to 6 years with developmental speech delay were examined. All patients were randomized into 2 clinically comparable groups: the 1st (study) group included 35 patients who received medical treatment in accordance with clinical recommendations in combination with the use of narrow-band optical radiation with an average wavelength of 650nm for 10 days; the 2nd (comparison) group consisted of 35 subjects who received standard drug therapy according to the established clinical recommendations. All patients underwent a comprehensive clinical examination and a special neurological investigation, including electroencephalography and electromyography, as well as an assessment of the development of speech functions and dynamic coordination of gesture, the level of social and communication skills development and neuropsychological processes. RESULTS: The following data were obtained during the complex treatment with the inclusion of narrow-band optical radiation with an average wavelength of 650 nm (red radiation): statistically significant improvement of speech development (p<0.05); improvement of values of social adaptation skills of medium (71%) (Z=2.769; p=006) and low level (29%) (Z=2.691; p=0.007); significant positive dynamics of speech status (Z=3.911; p=0.000); spontaneous activity relief at rest, indicating normalization of muscle tone. CONCLUSION: The inclusion of photochromotherapy in standard therapeutic regimens for children with developmental speech delay on the GSU type of I, II degrees contributes to a significantly confirmed pronounced clinical improvement and can be recommended for practical health care.

[Results of surgical treatment of children with Chiari I malformation using differentiated intraoperative tactics of choosing the volume of intervention]. / Rezul'taty khirurgicheskogo lecheniya detei s mal'formatsiei Kiari I tipa pri primenenii differentsirovannoi intraoperatsionnoi taktiki vybora ob"ema vmeshatel'stva.

BACKGROUND: Despite the presence of numerous publications and analytical reviews in the foreign literature, there is no universally accepted algorithm for the surgical treatment of Chiari I malformation (MC I) in children. Moreover, in the domestic literature, the number of publications devoted to the problems of surgical treatment of MC I in children is significantly limited, which, in our opinion, this is the reason for the relevance of this work. OBJECTIVE: To study the results of surgical treatment of children with MC I when applying differentiated tactics of intraoperative choice of intervention volume. MATERIAL AND METHODS: The results of neurological examination and surgical treatment of 43 patients aged from 1 to 17 years (mean age 8.48 years) were analyzed. The decision on the need for duraplasty was made intraoperatively when signs of persisting compression of subarachnoid spaces after extradural decompression were detected. Clinical manifestations were assessed according to neurological data before discharge, as well as in long-term period with a follow-up from 6 months to 5 years via survey. RESULTS: Duraplasty was required in 28% of cases. Respiratory disorders disappeared in all patients immediately after surgery and were absent thereafter. Positive dynamics was noted in terms of restoration of the rate of speech development. Headache persisted in 7 (21%) patients, movement, sensation disorders and cerebellar symptoms - in 4 (12%), vomiting and bulbar symptoms - in 2 (6%) patients. There was no difference in the efficacy of surgery with and without duraplasty. None of the parameters evaluated preoperatively had a significant association with the intraoperative decision on the need for duraplasty. CONCLUSION: In our opinion, final decision on surgical strategy in children with Chiari malformation type I should be made considering intraoperative assessment of extradural decompression. The last one is probably associated with individual characteristics of patients.

All-fiber high-power erbium-doped laser system generating optical pulses with a duration of 200 µs to 5 ms for fractional photo-rejuvenation.

An all-fiber high-power erbium-doped fiber laser (EDFL) source generating optical pulses from 200 µs to 5 ms with a stable rectangular envelope for fractional photo-rejuvenation is proposed and experimentally demonstrated. A master oscillator power amplifier (MOPA) configuration composed of a master oscillator, an acousto-optic modulator (AOM), and a one-stage amplifier is designed and employed in the EDFL to serve as an efficient laser system with excellent output performance. To avoid multistage amplifiers, the master oscillator generates 1.5 W, and a Yb-free Er-doped large-mode-area (LMA) active fiber is used for a one-stage power amplifier. There are two benefits to this approach: first, modulation of both pump and seed pulses is used to achieve clear rectangular shaped pulses without amplified spontaneous emission (ASE) growth; and second, there are no power limitations in the amplifier and undesirable 1 µm ASE compared to Er/Yb systems. We have reached 28.6 W of peak power with 26% slope efficiency limited only by available pump power, so the system can be easily scaled for achieving a higher peak power.

Vacuum breakdown in magnetic dipole wave by 10-PW class lasers.

The vacuum breakdown by 10-PW-class lasers is studied in the optimal configuration of laser beams in the form of an m-dipole wave, which maximizes the magnetic field. Using 3D PIC simulations we calculated the threshold of vacuum breakdown, which is about 10 PW. We examined in detail the dynamics of particles and identified particle trajectories which contribute the most to vacuum breakdown in such highly inhomogeneous fields. We analyzed the dynamics of the electron-positron plasma distribution on the avalanche stage. It is shown that the forming plasma structures represent concentric toroidal layers and the interplay between particle ensembles from different spatial regions favors vacuum breakdown. Based on the angular distribution of charged particles and gamma photons a way to experimentally identify the process of vacuum breakdown is proposed.

Particle trajectories, gamma-ray emission, and anomalous radiative trapping effects in magnetic dipole wave.

In studies of interaction of matter with laser fields of extreme intensity there are two limiting cases of a multibeam setup maximizing either the electric field or the magnetic field. In this work attention is paid to the optimal configuration of laser beams in the form of an m-dipole wave, which maximizes the magnetic field. We consider in such highly inhomogeneous fields the advantages and specific features of laser-matter interaction, which stem from individual particle trajectories that are strongly affected by gamma photon emission. It is shown that in this field mode qualitatively different scenarios of particle dynamics take place in comparison with the mode that maximizes the electric field. A detailed map of possible regimes of particle motion (ponderomotive trapping, normal radiative trapping, radial, and axial anomalous radiative trapping), as well as angular and energy distributions of particles and gamma photons, is obtained in a wide range of laser powers up to 300 PW, and it reveals signatures of radiation losses experimentally detectable even with subpetawatt lasers.

[3D modeling for planning of minimally invasive approach to the orbit]. / Ispol'zovanie 3D-modelirovaniya dlya planirovaniya minimal'no invazivnogo dostupa k oblasti orbity. Sluchai iz praktiki i obzor literatury.

OBJECTIVE: To demonstrate own experience in 3D modeling for planning of minimally invasive approach to the orbit and anterior skull base. MATERIAL AND METHODS: A 17-year-old patient admitted to the Department of Pediatric Neurosurgery with complaints of decreased visual acuity of the left eye, lacrimation and exophthalmos. MRI revealed a tumor of the left orbit. We have preoperatively modeled frontoorbital region, anterior skull, as well as eyeball and tumor within the same model. Considering young age and potentially favorable prognosis of disease, we preferred a minimally invasive intervention (microsurgical resection of tumor through minimally invasive frontoorbital access). RESULTS: Total resection of tumor was followed by examination of anterior skull base. There was postoperative regression of visual disturbances, lacrimation and exophthalmos. Sutures were removed after 5 days, and the patient was discharged. CONCLUSION: Minimally invasive frontoorbital access is adequate for approach to the orbit, anterior and middle cranial fossa, adequate resection of orbital tumor and examination of anterior skull base. 3D modeling is an additional preoperative tool to improve the quality of preoperative planning and facilitate intraoperative navigation.

Broadband gain performance in the mid-IR using supercontinuum: 2.7 µm gain in high-purity Er3+doped tungsten tellurite glass fibers.

This paper presents an experimental study of broadband mid-IR amplification that is carried out, for the first time, to the best of our knowledge, in an erbium-doped tungsten tellurite fiber. A simple, robust supercontinuum source based on a tapered germanate fiber is developed as a seed input in the region of 1.5-3 µm. We show that gain by a factor of 5 on one pass can be achieved in the 2.7 µm range by pumping a low-cost, high-efficiency diode laser at 976 nm using high-purity tellurite glass fibers.

Mechanism of the enhancing effect of glycyrrhizin on nifedipine penetration through a lipid membrane.

The saponin glycyrrhizin from liquorice root shows the ability to enhance the therapeutic activity of other drugs when used as a drug delivery system. Due to its amphiphilic properties, glycyrrhizin can form self-associates (dimers, micelles) and supramolecular complexes with a wide range of hydrophobic drugs, which leads to an increase in their solubility, stability and bioavailability. That is why the mechanism of the biological activity of glycyrrhizin is of considerable interest and has been the subject of intensive physical and chemical research in the last decade. Two mechanisms have been proposed to explain the effect of glycyrrhizin on drug bioavailability, namely, the increase in drug solubility in water and enhancement of the membrane permeability. Interest in the membrane-modifying ability of glycyrrhizic acid (GA) is also growing at present due to its recently discovered antiviral activity against SARS-CoV-2 Bailly and Vergoten (2020) [1]. In the present study, the passive permeability of the DOPC lipid membrane for the calcium channel blocker nifedipine was elucidated by parallel artificial membrane permeability assay (PAMPA) and full atomistic molecular dynamics (MD) simulation with free energy calculations. PAMPA experiments show a remarkable increase in the amount of nifedipine (NF) permeated with glycyrrhizin compared to free NF. In previous studies, we have shown using MD techniques that glycyrrhizin molecules can integrate into the lipid bilayer. In this study, MD simulation demonstrates a significant decrease in the energy barrier of NF penetration through the lipid bilayer in the presence of glycyrrhizin both in the pure DOPC membrane and in the membrane with cholesterol. This effect can be explained by the formation of hydrogen bonds between NF and GA in the middle of the bilayer.

[Combination of tumors of different histogenesis in pediatric neurosurgery]. / Sochetanie opukholei razlichnogo gistogeneza v detskoi neirokhirurgii.

Multiple gliomas are determined by synchronous two or more tumors located in different brain regions. It is important to distinguish multiple primary tumors and metastatic brain lesion. In the first case, tumor spread can`t be explained by dissemination along the cerebrospinal fluid pathways, commissural fibers or local metastases. Multiple primary tumors with different histological structures are called bidermal neoplasms. Surgery is preferred in these patients with severe symptoms. The purpose of surgery is maximum resection of tumor. Follow-up may be advisable for small tumors without clinical manifestations. Treatment of multiple gliomas includes surgery, radiotherapy and chemotherapy. Multiple tumor process in children is much more severe compared to a single neoplasia that requires neurological and neuroimaging control and determines treatment strategy. The authors report 3 children with multicentric gliomas, discuss the various aspects of diagnosis and treatment of multiple gliomas and formulate the recommendations for the treatment based on own clinical experience and literature data.

Modeling of Interspecific Interaction of Yersinia pseudotuberculosis and Listeria monocytogenes in a Mixed-Species Biofilms with Microorganisms Isolated from Coastal Waters of the Sea of Japan.

We studied the possibility of formation of mixed-species biofilms by Yersinia pseudotuberculosis and Listeria monocytogenes with marine saprotrophic bacteria Flavobacterium sp. and Micrococcus luteus isolated from the coastal waters of the Sea of Japan in summer. Model experiments showed that Flavobacterium sp. and Micrococcus luteus can form both single- and mixed-species biofilms with the specified pathogenic bacteria thus stimulating their growth. This can contribute to the preservation of the pathogens in the marine environment.

[Skull defect repair in children using a 3D-printing technology]. / Kranioplastika defektov cherepa u detei s ispol'zovaniem tekhnologii 3D-pechati.

Currently, 3D-printing technologies are increasingly used in neurosurgery. Active development of this approach is valuable to improve preoperative planning, intraoperative navigation, and manufacturing of realistic training models. In this manuscript, the authors report an experience of the pediatric neurosurgical department of the Almazov National Medical Research Center regarding 3D-printing technologies in manufacturing of individual implants for skull defect closure. The main aspects of this technology, advantages and disadvantages are considered. Moreover, the authors describe several cases of creating individual implants for children with skull defects of various origins, dimensions and complexity.

Laser-driven plasma pinching in e

The cascaded production and dynamics of electron-positron plasma in ultimately focused laser fields of extreme intensity are studied by three-dimensional particle-in-cell simulations with the account of the relevant processes of quantum electrodynamics (QED). We show that, if the laser facility provides a total power above 20 PW, it is possible to trigger not only a QED cascade but also pinching in the produced electron-positron plasma. The plasma self-compression in this case leads to an abrupt rise of the peak density and magnetic (electric) field up to at least 10^{28}cm^{-3} and 1/20 (1/40) of the Schwinger field, respectively. Determining the actual limits and physics of this process might require quantum treatment beyond the used standard semiclassical approach. The proposed setup can thus provide extreme conditions for probing and exploring fundamental physics of the matter and vacuum.

High-energy femtosecond pulse shaping, compression, and contrast enhancement using multicore fiber.

Nonlinear spatiotemporal dynamics of femtosecond pulses in a hexagonal seven-core silica fiber pumped by a sub-µJ 370 fs Er:fiber chirped pulse amplification (CPA) system were studied. Nonlinear pulse shaping and compression in the central core and pedestal coupling to the outer cores were directly measured by frequency-resolved optical gating. Further compression of the pulses spectrally broadened in the multicore fiber down to 53 fs was demonstrated. Two orders of magnitude contrast enhancement of the pulses after compression was observed.

Dual-band Tm3+-doped tellurite fiber amplifier and laser at 1.9 µm and 2.3 µm.

Ultrabroadband amplification and two-color CW lasing simultaneously near 1.9 µm and 2.3 µm in a Tm3+-doped tellurite fiber were demonstrated experimentally, for the first time to the best of our knowledge. A low-loss Tm3+-doped core fiber from TeO2-ZnO-La2O3-Na2O glasses stable against crystallization was produced by a special technique, providing a low concentration of hydroxyl groups. Supercontinuum from a highly GeO2 doped silica fiber pumped by an Er fiber laser system was used as a seed for an amplifier. A maximum gain of 30 dB and 7 dB was measured at 1.9 µm and 2.3 µm, respectively. We report detailed experimental and theoretical studies, which are in a very good agreement, of laser amplification and generation in the manufactured fiber with carefully measured and calculated parameters. A quantitatively verified numerical model was used to predict power scalability at 2.3 µm in schemes with optimized parameters at increased pump power. The presented results show that a high-quality tellurite fiber is a promising candidate for developing lasers in the 2.3 µm atmospheric window which are particularly relevant for applications in gas sensing, eye-safe laser radars, breath analysis, remote sensing and stand-off trace gas detection.

[Intraoperative fluorescence diagnosis using 5-aminolevulinic acid in surgical treatment of children with recurrent neuroepithelial tumors]. / Rezul'taty intraoperatsionnoi fluorestsentnoi diagnostiki s ispol'zovaniem 5-aminolevulinovoi kisloty pri khirurgicheskom lechenii detei s retsidivami neiroepitelial'nykh opukholei.

AIM: To analyze the efficacy and safety of 5-aminolevulinic acid for intraoperative fluorescence diagnosis (FD) during repeated surgery for recurrent neuroepithelial tumors (NETs) in children. MATERIAL AND METHODS: We performed a retrospective analysis of the results of recurrent NET resection in 13 children aged from 3 to 17 years in the period between December 2013 and May 2015. The source of 5-ALA was a drug "Alasens" that was administered at a dose of 20 mg/kg of body weight 4 h before the beginning of tumor resection. A visual scale was used to evaluate the fluorescence intensity. The drug was used with the informed consent of the child's parents and approval of the Polenov Neurosurgical Institute ethics committee. All patients underwent complex clinical and introscopic examination in the pre- and postoperative periods and a repeated histological tumor examination. RESULTS: There was no fluorescence in 4 cases (Gr I in 2 cases; Gr II in 2 cases). Grade 1 fluorescence (Gr II) was observed in one case, and grade 2-3 fluorescence was observed in the remaining 8 patients. Total and subtotal tumor resection was achieved in 11 (84.6%) of 13 patients. There were no clinically significant adverse effects. A transient increase in transaminases was observed in 2 patients. Two girls had an elevated photosensitivity to light for two days. CONCLUSION: FD is a safe technique in childhood and can improve intraoperative detection of NET during its repeated growth as well as differentiate the tumor from pathological tissues of non-tumorous nature, which increases completeness of blastomatous tissue removal. However, the character and intensity of fluorescence may change in recurrent NETs. Further research is required to investigate the FD effectiveness in various age patients with tumors of a different histological structure and malignancy in the case of both primary and recurrent lesions.

Spectroscopic and molecular dynamics characterization of glycyrrhizin membrane-modifying activity.

Glycyrrhizic acid (GA) is a triterpene glycoside extracted from licorice root. Due to its amphiphilicity GA is capable of forming complexes with a variety of hydrophobic molecules, substantially increasing their solubility. GA can enhance the therapeutic effects of various drugs. It was hypothesized that the increased bioavailability of the drug by GA is not only due to increased solubility, but also to enhancement of drug permeability through cell membranes. In this study the interaction of GA with POPC liposomes and model DOPC, POPC and DPPC bilayers was investigated by NMR with addition of shift reagents and MD simulations. This work helps to better understand the mechanism of enhanced drug bioavailability in the presence of GA. NMR and MD reveal that GA does penetrate into the lipid bilayer. NMR shows that GA changes the mobility of lipids. GA is predominantly located in the outer "half-layer" of the liposome and that the middle of the hydrophobic tails is the preferred location. GA freely passes through the bilayer surface to the inner part bringing a few water molecules. Also both approaches indicate pore formation in the presence of GA. The GA interaction with membranes is an additional aspect of the biological activity of GA-based drug delivery systems.

Toward a mid-infrared femtosecond laser system with suspended-core tungstate-tellurite glass fibers.

A simple design of a fiber laser system for generating high-quality pulses with a duration of order 100 fs with ultrabroad wavelength tunability in the 2-5 µm range is discussed. This design incorporates conventional fs near-IR lasers and specially developed tungstate-tellurite fibers with two zero-dispersion wavelengths (ZDW) and relies on nonlinear wavelength conversion via either soliton self-frequency shift (SSFS) or red-shifted dispersive wave (DW) generation. The fiber parameters needed for such optical conversion have been scanned numerically and showed a possibility of SSFS beyond 4 µm and of DW generation beyond 5 µm. We have also studied and prepared tungstate-tellurite glasses and preforms that are highly stable against crystallization, exhibit extremely low level of hydroxyl groups absorption, and from which the suspended-core two-ZDW fibers can be manufactured.

[Hygienic assessment of living conditions and morbidity of the population in the port cities of the Sakhalin region].

The aim of this study was to perform a comprehensive hygienic assessment of environmental conditions in the port cities of the Sakhalin region to identify priority risk factors affecting on population health and management decisions for the optimization of living conditions. As a result of the assessment of risk and damages for public health from the effects of air pollution on the dose-response, effects were found to excess of impact on the target organs by 10 times. The main ecotoxicant was determined to be manganese oxide, which is associated with a priority manganese content in soil samples ofport cities. The positive dynamics of the gain in the accumulation of soil heavy metals according to the total index indicates to the existence of problems for soil contamination. Analysis of demographic variables shows that the population of the Sakhalin region in general and the port cities in particular relates to a regressive type. The main causes of the population decline are mortality and migration outflow of able-bodied population in other regions of Russia. However, in the port cities there is an increase in the number of work places, contributing to an increase in the labor force. The primary and general morbidity of the population ofport cities is characterized by higher levels compared with the average for the Sakhalin Region and the Far Eastern Federal District. Among all the classes of diseases as priority ones there are marked "neoplasm", "diseases of the nervous system", "respiratory diseases", "diseases of the skin and subcutaneous tissue". Port cities occupy the top ranking places on the incidence of malignant tumors among the cities of the Sakhalin region.

Impact of quantum effects on relativistic electron motion in a chaotic regime.

The impact of quantum effects on electron dynamics in a plane linearly polarized standing wave with relativistic amplitudes is considered. Using spectral analysis of Lyapunov characteristic exponents with and without radiation losses we show that the contraction effect of phase space due to the radiation reaction force in the classical form does not occur in the quantum case when the discreteness of photon emission is taken into account. It is also demonstrated that electron bunch kinetics has a diffusion solution rather than the d'Alambert type solution as in the classical description. For this case, we applied the Markov chain formalism and showed that this method gives exact characteristics of electron bunch evolution, such as motion of the center of mass and electron bunch dimensions.

[Granulomatous inflammation in the bed of resected cerebral cavernoma in a child, caused by a hemostatic agent].

OBJECTIVE: The study presents a clinical observation of foreign body granuloma, which is rare productive inflammation, developed on treatment with a hemostatic material upon removal of cerebral cavernoma. MATERIAL AND METHODS: A 4-year-old boy operated on for left parietal lobe cavernoma was diagnosed with a mass lesion during a follow-up MRI examination 4 months after surgery. The patient was re-operated in connection with suspected abscess formation. The pathological tissue was subjected to the histological and immunohistochemical examination. RESULTS: Inflammation was accompanied by the formation of foreign body granulomas, and, in some areas, had immune nature with signs of focal destructive vasculitis, delayed maturation of the granulation tissue, and disturbance of the current organization and encapsulation processes. It is worth noting that granulomatous inflammation around a hemostatic material in the brain has no specific features during introscopy and mimics an abscess or tumor recurrence. CONCLUSION: The use of hemostatic materials upon resection of cerebral cavernous malformations may cause formation of granuloma mimicking disease relapse or abscess in the long term period. To prevent granulomatous inflammation, removal of a hemostatic material, if possible, from the surgical field is recommended when reliable hemostasis is achieved.