Horizontal dispersion in shelf seas: High resolution modelling as an aid to sparse sampling

The ability of a hydrodynamic model to reproduce the results of a dye release experiment conducted in a wide shelf sea environment was investigated with the help of the Massachusetts Institute of Technology general circulation model (MITgcm). In the field experiment a fluorescent tracer, Rhodamine WT, was injected into the seasonal pycnocline, and its evolution was tracked for two days using a towed undulating vehicle equipped with a fluorometer and a CTD. With a 50. m horizontal resolution grid, and with three different forcings initialized in the model (viz: tides, stationary current, and wind stress on the free surface), it was possible to replicate the dye patch evolution quite accurately. The mechanisms responsible for the enhancement of horizontal dispersion were investigated on the basis of the model results. It was found that enhancement of the dye dispersion was controlled by vertically sheared currents that, in combination with vertical diapycnal mixing, led to a substantial increase in the "effective" horizontal mixing. The values of "effective" horizontal mixing found from the model runs were in good agreement with those obtained from in-situ data, and the probable degree to which the observational techniques undersampled the dye patch was revealed

Focusing of baroclinic tidal energy in a canyon

Strong three-dimensional focusing of internal tidal energy in the Petite Sole Canyon in the Celtic Sea is analyzed using observational data and numerical modeling. In a deep layer (500-800 m) in the center of the canyon, shear variance was elevated by an order of magnitude. Corresponding large vertical oscillations of deep isotherms and a local maximum of horizontal velocity were replicated numerically using the MITgcm. The elevated internal tidal activity in the deep part of the canyon is explained in terms of the downward propagation and focusing of multiple internal tidal beams generated at the shelf break. The near-circular shape of the canyon head and steep bottom topography throughout the canyon (steeper than the tidal beam) create favorable conditions for the lens-like focusing of tidal energy in the canyon\u27s center. Observations and modeling show that the energy focusing greatly intensifies local diapycnal mixing that leads to local formation of a baroclinic eddy

The problem of mismatches between CT scan and DXA results

Background. It is reported that radiodensity measured in Hounsfield units becomes more and more popular in bone property assessment, however also mismatch with DXA results is observed.Purpose. The aim of this study is to evaluate the relationships between the results of DXA and CT with a focus on explanations for observed discrepancies.Material and Methods. This is a cross-sectional study; forty patients were enrolled, all patients underwent DXA and CT. A bone mineral density BMD (g/cm2) was calculated for each vertebra of a lumbar spine (L1-L4 inclusive), neck, upper neck, shaft, Wards triangle and trochanter of hip. Bone radiodensity in HU was taken from each vertebral body in the sagittal, axial and coronal planes. A total vertebra body radiodensity including cortical bone and radiodensity of only cancellous bone were calculated. To assess a potential impact on DXA and CT data agreement a mean radiodensity and square of the right and left vertebral pedicles and facet joints were measured for each vertebra.Results. A strong correlation between BMD measured using DXA and CT data was estimated with a multiply r accounting for 0.84169, p < 0.0001, however the most contributing parameters were those calculated for facet joints. It has been detected that both radiodensity of only a cancellous bone and total have a weak correlation with matching BMD measurements of a proximal femur.Conclusion. The results of DXA could be strongly influenced by hypertrophic changes of facet joints. Both CT and DXA measurements taken from a lumbar spine may have a mismatch with figures taken from hip

CENTRAL WAVELENGTH ADJUSTMENT OF LIGHT EMITTING SOURCE IN INTERFEROMETRIC SENSORS BASED ON FIBER-OPTIC BRAGG GRATINGS

The paper is focused on the investigation of fiber-optic interferometric sensor based on the array of fiber Bragg gratings. Reflection spectra displacement mechanism of the fiber Bragg gratings under the external temperature effects and the static pressure is described. The experiment has shown that reflection spectra displacement of Bragg gratings reduces the visibility of the interference pattern. A method of center wavelength adjustment is proposed for the optical radiation source in accord ance with the current Bragg gratings reflection spectra based on the impulse relative modulation of control signal for the Peltier element controller. The semiconductor vertical-cavity surface-emitting laser controlled by a pump driver is used as a light source. The method is implemented by the Peltier element controller regulating and stabilizing the light source temperature, and a programmable logic-integrated circuit monitoring the Peltier element controller. The experiment has proved that the proposed method rendered possible to regulate the light source temperature at a pitch of 0.05 K and adjust the optical radiation source center wavelength at a pitch of 0.05 nm. Experimental results have revealed that the central wavelength of the radiation adjustment at a pitch of 0.005 nm gives the possibility for the capacity of the array consisting of four opticalfiber sensors based on the fiber Bragg gratings. They are formed in one optical fiber under the Bragg grating temperature change from 0° C to 300° C and by the optical fiber mechanical stretching by the force up to 2 N

Совместное использование разработанных коллагенсодержащих комплексов и культуры клеток для создания новых тканевых эквивалентов

The purpose of the study is to assess the possibility of applying the integrated module as the basis of a celltissue equivalent for treatment of wounds of skin and soft tissues. In the frame of the set task the following problems were being solved: research of the spatial structure and architectonics of the surface of the developed base collagen-containing materials and their biocompatibility with cell cultures.Materials and methods. The study of a material which is a two-layer complex film, consisting of collagen and polysaccharide components was carried out. The collagen was separated from the dermis and was then impregnated with particulate demineralized bone matrix (DCM) according to the original methodology. For the purposes of the study the dehydrated material was created in the form of a film. Electron microscopic examination of surfaces was performed on scanning electron microscope JEOL JSM-IT300LV in high vacuum and at low values of probe current (< 0,1 nА). Studies to assess the viability of the cells cultivated on films of collagen material (tested for cytotoxicity and the adhesive capacity) were performed in vitro using strains of diploid human fibroblasts 4–6 passage. The culture condition was visually assessed using an inverted Leica microscope DM IL (Carl Zeiss, Austria), equipped with a computerizes program of control of culture growth (Leica IM 1000).Results. The data obtained in the study of the surface structure of the developed complex module showed that it seems to be promising as a basic component of the cellular-tissue system with its large number of structural formations for fixation of the cells and a well-organized barrier layer capable of vapor - permeability. Experiments in vitro confirmed the absence of toxicity of the material being studied in relation to the culture of dermal human fibroblasts, suggesting the possibility of creation on its basis of cell-tissue complex and further experimental studies in vivo.Conclusion. Thus it was experimentally confirmed that the physical characteristics of the developed integrated module satisfy the requirements for the materials for cultivation of cells. The absence of cytotoxicity on the model of a culture of dermal human fibroblasts allows to make a conclusion about a possibility of its use as the basis of cell-tissue equivalent. Preliminary results indicate the advisability of further experiments in vivo aimed at improving complex collagen-containing materials, the development of different ways of their application and clinical evaluation of the effectiveness in the treatment of wounds of various genesis.Цель исследования – оценка возможности применения созданного комплексного модуля в качестве основы клеточно-тканевого эквивалента для лечения ран кожи и мягких тканей. В рамках поставленной цели решались задачи по изучению пространственной структуры и архитектоники поверхности разработанных базовых коллагенсодержащих материалов и их биосовместимости с клеточными культурами.Материал и методы. Проведено исследование материала, который представляет собой двухслойный пленочный комплекс, состоящий из коллагенового и полисахаридного компонентов. Коллаген выделялся из дермы и был импрегнирован мелкодисперсным деминерализованным костным матриксом (ДКМ) по оригинальной методике. Для исследования дегидратированный материал был выполнен в виде пленки. Электронно-микроскопическое исследование поверхности проведено на сканирующем электронном микроскопе JEOL JSM-IT300LV (Япония) в режиме высокого вакуума и при низких значениях тока зонда (< 0,1 нА). Исследования по оценке жизнеспособности клеток в условиях культивирования на пленках из коллагенсодержащего материала (тестирование на цитотоксичность и адгезивную способность) проводили in vitro с использованием штаммов диплоидных фибробластов человека 4–6-го пассажа. Состояние культуры оценивали визуально с помощью инвертированного микроскопа Leica DM (Carl Zeiss, Австрия), оснащенного компьютерной программой контроля роста культуры (Leica IM 1000).Результаты. Данные, полученные при изучении структуры поверхности разработанного комплексного модуля, показали, что он представляется перспективным в качестве базового компонента клеточно-тканевой системы: наличие большого количества структурных образований для фиксации клеток и хорошо организованного барьерного слоя, способного к паро- и водопроницаемости. Таким образом, экспериментально подтверждено соответствие физических характеристик разработанного базового комплекса требованиям, предъявляемым к материалам для культивирования клеток. Показано отсутствие цитотоксичности на модели культуры дермальных фибробластов человека, что позволяет сделать вывод о возможности его использования в качестве основы клеточно-тканевого эквивалента. Полученные предварительные результаты указывают на целесообразность дальнейшего проведения экспериментов in vivo, направленных на совершенствование комплексных коллагенсодержащих материалов, разработку различных способов их применения и клиническую оценку эффективности при лечении ран различного генеза

RESEARCH ON NEW BISMUTH-SUBSTITUTED APATITES

The work was carried out within the framework of the Strategic Academic Leadership Program “Priority 2030” (internal project number N-413-99_2023-2024)

Joint use of developed collagen-containing complexes and cell cultures in creating new tissue equivalents

The purpose of the study is to assess the possibility of applying the integrated module as the basis of a celltissue equivalent for treatment of wounds of skin and soft tissues. In the frame of the set task the following problems were being solved: research of the spatial structure and architectonics of the surface of the developed base collagen-containing materials and their biocompatibility with cell cultures.Materials and methods. The study of a material which is a two-layer complex film, consisting of collagen and polysaccharide components was carried out. The collagen was separated from the dermis and was then impregnated with particulate demineralized bone matrix (DCM) according to the original methodology. For the purposes of the study the dehydrated material was created in the form of a film. Electron microscopic examination of surfaces was performed on scanning electron microscope JEOL JSM-IT300LV in high vacuum and at low values of probe current (< 0,1 nА). Studies to assess the viability of the cells cultivated on films of collagen material (tested for cytotoxicity and the adhesive capacity) were performed in vitro using strains of diploid human fibroblasts 4–6 passage. The culture condition was visually assessed using an inverted Leica microscope DM IL (Carl Zeiss, Austria), equipped with a computerizes program of control of culture growth (Leica IM 1000).Results. The data obtained in the study of the surface structure of the developed complex module showed that it seems to be promising as a basic component of the cellular-tissue system with its large number of structural formations for fixation of the cells and a well-organized barrier layer capable of vapor - permeability. Experiments in vitro confirmed the absence of toxicity of the material being studied in relation to the culture of dermal human fibroblasts, suggesting the possibility of creation on its basis of cell-tissue complex and further experimental studies in vivo.Conclusion. Thus it was experimentally confirmed that the physical characteristics of the developed integrated module satisfy the requirements for the materials for cultivation of cells. The absence of cytotoxicity on the model of a culture of dermal human fibroblasts allows to make a conclusion about a possibility of its use as the basis of cell-tissue equivalent. Preliminary results indicate the advisability of further experiments in vivo aimed at improving complex collagen-containing materials, the development of different ways of their application and clinical evaluation of the effectiveness in the treatment of wounds of various genesis

In vitro dendritic cell maturation isolated from healthy people and patients with Staphylococcus aureuscaused chronic osteomyelitis

Here we present the data comparing maturation of peripheral blood mononuclear cell-derived dendritic cells (DCs) isolated from healthy volunteers and Staphylococcus aureus-positive patients with chronic osteomyelitis. Dendritic cells were cultured in a standard maturation cell medium (RPMI-1640,  supplemented with antibiotics, L-glutamine, 15% calf embryonic serum) added with interleukin-4 and granulocyte-macrophage colony-stimulating factor, followed by adding a stimulating factor cocktail containing interleukin-1β, tumor necrosis factor-α, interleukin-6, and prostaglandin E2. Dendritic cell maturation was analyzed by estimating visual characteristics under Zeiss ODSERVER.Z1 inverted microscope using Axiovision Rel.4.8 imaging software as well as light and phase-contrast microscopy at magnification of ×40, ×100, ×200, ×400, ×630. Dendritic cell immunophenotyping was carried out by using a panel of anti-human monoclonal antibodies: anti-CD80 FITC-conjugated, anti-CD86 (B7–2) PE-conjugated, anti-HLA-DR PC7-conjugated (all from Beckman Coulter, USA), anti-CD14 PerCP-Cy5.5-conjugated, anti-CD83 APC-conjugated, anti-CD40 PE-Cy7-conjugated (Becton Dickinson, USA) as well as isotype-matched control antibodies on the FACS Canto II f low cytometer (Becton Dickinson, USA). It was shown that while maturation dendritic cells derived both from patients or volunteers increased in size and underwent dendrite formation. Moreover, expression of CD86, CD83, CD80, and CD40 markers on dendritic cells derived from patients vs. volunteers was lowered. However, DC stimulation resulted in significantly increased percentage of DCs positive for CD83 DCs co-stimulation molecules CD86, CD80, CD40 chronic osteomyelitis. However, such differences found in immature DCs in both groups disappeared upon maturation, so that expression of the key markers on day 10 was maintained at close level. In particular, expression of CD83 differentiation marker and the CD80 co-stimulation molecule on DCs from patients vs. volunteers was increased stronger. Thus, a maturation potential in DCs isolated from patients with Staphylococcus aureus-caused chronic osteomyelitis was not impaired in vitro. The data obtained open up an opportunity to use dendritic cells as a natural adjuvant-substituting component for development of individualized vaccines in treatment and prevention of recurrent chronic osteomyelitis

SCALE FACTOR DETERMINATION METHOD OF ELECTRO-OPTICAL MODULATOR IN FIBER-OPTIC GYROSCOPE

Subject of Research. We propose a method for dynamic measurement of half-wave voltage of electro-optic modulator as part of a fiber optic gyroscope. Excluding the impact of the angular acceleration o​n measurement of the electro-optical coefficient is achieved through the use of homodyne demodulation method that allows a division of the Sagnac phase shift signal and an auxiliary signal for measuring the electro-optical coefficient in the frequency domain. Method. The method essence reduces to decomposition of step of digital serrodyne modulation in two parts with equal duration. The first part is used for quadrature modulation signals. The second part comprises samples of the auxiliary signal used to determine the value of the scale factor of the modulator. Modeling is done in standalone model, and as part of a general model of the gyroscope. The applicability of the proposed method is investigated as well as its qualitative and quantitative characteristics: absolute and relative accuracy of the electro-optic coefficient, the stability of the method to the effects of angular velocities and accelerations, method resistance to noise in actual devices. Main Results. The simulation has showed the ability to measure angular velocity changing under the influence of angular acceleration, acting on the device, and simultaneous measurement of electro-optical coefficient of the phase modulator without interference between these processes. Practical Relevance. Featured in the paper the ability to eliminate the influence of the angular acceleration on the measurement accuracy of the electro-optical coefficient of the phase modulator will allow implementing accurate measurement algorithms for fiber optic gyroscopes resistant to a significant acceleration in real devices