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

Long term trends in the sea surface temperature of the Black Sea

There is growing understanding that recent deterioration of the Black Sea ecosystem was partly due to changes in the marine physical environment. This study uses high resolution 0.25° climatology to analyze sea surface temperature variability over the 20th century in two contrasting regions of the sea. Results show that the deep Black Sea was cooling during the first three quarters of the century and was warming in the last 15–20 years; on aggregate there was a statistically significant cooling trend. The SST variability over the Western shelf was more volatile and it does not show statistically significant trends. The cooling of the deep Black Sea is at variance with the general trend in the North Atlantic and may be related to the decrease of westerly winds over the Black Sea, and a greater influence of the Siberian anticyclone. The timing of the changeover from cooling to warming coincides with the regime shift in the Black Sea ecosystem

Glider observations of enhanced deep water upwelling at a shelf break canyon: a mechanism for cross-slope carbon and nutrient exchange

Using underwater gliders we have identified canyon driven upwelling across the Celtic Sea shelf-break, in the vicinity of Whittard Canyon. The presence of this upwelling appears to be tied to the direction and strength of the local slope current, which is in itself highly variable. During typical summer time equatorward flow, an unbalanced pressure gradient force and the resulting disruption of geostrophic flow can lead to upwelling along the main axis of two small shelf break canyons. As the slope current reverts to poleward flow, the upwelling stops and the remnants of the upwelled features are mixed into the local shelf water or advected away from the region. The upwelled features are identified by the presence of sub-pycnocline high salinity water on the shelf, and are upwelled from a depth of 300 m on the slope, thus providing a mechanism for the transport of nutrients across the shelf break onto the shelf

Auditory impairment from acoustic seal deterrents predicted for harbour porpoises in a marine protected area

Management interventions to reduce human–wildlife conflict can have unintended consequences for non-target species. Acoustic deterrent devices (ADDs) are used globally by the aquaculture sector. However, the potential for these sound emissions to impact non-target species, such as cetaceans, has not yet been quantified at population relevant spatial scales. To better understand the extent of potential impacts on cetaceans, such as harbour porpoises, we used acoustic modelling to investigate levels of ADD noise throughout the west coast of Scotland and across a Special Area of Conservation (SAC) for this species. Using an energy-flux acoustic propagation model and data on aquaculture sites known to be using ADDs, we predicted the spatial extent of ADD noise on the Scottish west coast from 1 February 2017 to 31 January 2018. Noise maps were produced to determine the risk of auditory impairment for harbour porpoises under a range of scenarios which assumed single or multiple ADDs and simultaneous use across all sites. The acoustic propagation model performed well when tested against field measurements up to 5 km, with 98% of sound exposure level (SEL) predictions within ±10% of the measurements. Predictions of SELs over a 24-hr period suggested extensive temporary hearing loss zones (median radius: ~28 km) for harbour porpoises around aquaculture sites. Assuming a single device at each site, 23% of the harbour porpoise SAC was predicted to be exposed to ADD noise sufficient to induce a temporary threshold shift, and under the worst-case scenario (multiple, continuously running devices per site with an aggregate duty cycle of 100%), levels exceeding permanent threshold shift could reach 0.9% of the SAC. Policy implications. This study highlights the potential for ‘collateral damage’ from interventions such as acoustic deterrent devices (ADDs) which are intended to reduce human–wildlife conflicts with pinnipeds but may affect the long-term health and habitat use of non-target species. This is especially true for harbour porpoises which are protected under the EU and UK Habitats Regulations. The aquaculture industry, policymakers and regulators in countries where ADDs are used should consider these findings when attempting to mitigate pinniped depredation

EVALUATION METHOD FOR PARASITIC EFFECTS OF THE ELECTRO-OPTICAL MODULATOR IN A FIBER OPTIC GYROSCOPE

Subject of Research.The paper proposes an original method for studying the parasitic effects in the electro-optic modulator of the fiber optic gyroscope. Proposed method is based on the usage of a special waveform phase modulation signal. Method. The essence of the proposed method lies in modification of serrodyne modulation signal, thereby providing a periodic displacement of the phase difference signal to the maximum of the interference curve. In this case, the intensity level reflects the influence of parasitic effects with the degree of manifestation being determined by the sequence of voltage control signals applied to the modulator. Enumeration of combinations of control signals and the corresponding intensity levels gives the possibility to observe an empirical dependence of the parasitic effects and use it later for compensation. Main Results. The efficiency of the proposed method is demonstrated by the program model of the fiber optic gyroscope. The results of the method application on a production sample of the device were obtained. Comparison with the results of direct estimate of the parasitic intensity modulation effect testifies to the effectiveness of the proposed method. Practical Relevance. The method can be used as a diagnostic tool to quantify the influence of parasitic effects in the electro-optic modulator of the fiber optic gyroscope as well as for their subsequent compensation

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

HABreports: Online Early Warning of Harmful Algal and Biotoxin Risk for the Scottish Shellfish and Finfish Aquaculture Industries

We present an on-line early warning system that is operational in Scottish coastal waters to minimize the risk to humans and aquaculture businesses in terms of the human health and economic impacts of harmful algal blooms (HABs) and their associated biotoxins. The system includes both map and time-series based visualization tools. A “traffic light” index approach is used to highlight locations at elevated HAB/biotoxin risk. High resolution mathematical modelling of cell advection, in combination with satellite remote sensing, provides early warning of HABs that advect from offshore waters to the coast. Expert interpretation of HAB, biotoxin and environmental data in light of recent and historical trends is used to provide, on a weekly basis, a forecast of the risk from HABs and their biotoxins to allow mitigation measures to be put in place by aquaculture businesses, should a HAB event be imminent

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)

Восстановление ограниченных дефектов суставного хряща с помощью клеточно-инженерных конструкций

Aim: to develop a three-dimensional composite cell-engineered constructs (CEC) for restoration of limited defects of the cartilage in experiment.Materials and methods. To create a cell-engineered constructs (CEC), were used collagenic carriers: «Chondro Gide» impermeable bilayer membrane and «Osteoplast» permeable matrix. A comparative study of their cytotoxic and adhesion properties was made in vitro. Chondroplastic potential of prepared CECs based on collagenous matrices with allogeneic mesenchymal stem cells (MSC) of the rabbit bone marrow grown on their surface was assessed in vivo. A cylindrical defect of the cartilage of the medial femoral condyle 3.3 mm in diameter at a depth of 1.5 mm was formed on both rabbit feet. Laboratory animals were divided into 3 groups: control group; Experiment 1 group with Chondro Gide used as the MSC carrier within CEC; Experiment 2 group using Osteoplast matrix. Upon experiment completion, a morphometric and histomorphologic research of tissue specimens was made. For statistical evaluation of the results a defect region recovery factor (RF) was offered and used. Results. After a 6-month observation period the control group showed partial recovery of the defect region with the recovery factor (RF) of 0.62 ± 0.06. The RF in Experiment 1 group equalled to 0.79 ± 0.07, Experiment 2 group revealed RF at the level of 0.88 ± 0.02. Statistical analysis of the research results shows that the use of CEC used in Experiment 2 group reduces a relative risk of therapeutic failures by 92.9%, and absolute risk – by 43.3% as compared to Experiment 1 group. Histomorphologic research data are indicative of a hyaline cartilage formation in the central defect zone, which is partially close to the intact cartilage to the maximum with zonality marked.Conclusion. Results of the research of the developed three-dimension cell-engineered constructs consisting of mesenchymal stem cells of the bone marrow grown on the Osteoplast permeable collagenic matrix show the formation of a cartilaginous hyaline tissue with a high level of structural organization in the area of its implantation. The thickness of a newly formed cartilage is insignifi cantly less than that of the preceding cartilaginous tissue, thus facilitating a dynamic distribution of the axial load on the articular surface, and as a whole this holds out hope for good long-term results. Therefore, based on the data obtained, we consider it reasonable to perform next investigation phases of the offered cell-engineered constructs for chondroplasty of limited cartilage defects. Цель. Разработать трехмерную комбинированную клеточно-инженерную конструкцию (КИК) для восстановления ограниченных повреждений суставного хряща в эксперименте. Материалы и методы. Для создания клеточно-инженерной конструкции (КИК) использованы коллагеновые носители: двухслойная непроницаемая мембрана «Chondro Gide» и проницаемая матрица «Остеопласт», проводилось сравнительное исследование их цитотоксических, адгезивных свойств in vitro. Хондропластический потенциал подготовленных КИК на основе коллагеновых матриц с выращенными на их поверхности аллогенными мезенхимальными стволовыми клетки (МСК) костного мозга кролика оценивался in vivo. Кроликам на обеих лапах был сформирован цилиндрический дефект суставного хряща внутреннего мыщелка бедренной кости диаметром 3,3 мм на глубину 1,5 мм. При этом лабораторные животные были разделены на 3 группы: контрольная; группа «Опыт 1», в которой в качестве носителя для МСК в составе КИК использовался «Chondro Gide»; группа «Опыт 2», где была применена матрица «Остеопласт». По завершении эксперимента проводились морфометрическое и гистоморфологическое исследование образцов тканей. Для статистической оценки результатов был предложен и использован коэффициент восстановления области дефекта (КВ).Результаты. Через 6 месяцев наблюдений в контрольной группе отмечено частичное восстановление области дефекта, коэффициент восстановления (КВ) составил 0,62 ± 0,06. В группе «Опыт 1» КВ был равным 0,79 ± 0,07, в группе «Опыт 2» КВ находился на уровне 0,88 ± 0,02. Статистическая оценка результатов исследования показывает, что применение КИК, используемой в группе «Опыт 2», позволяет снизить относительный риск наступления неблагоприятных исходов лечения на 92,9%, абсолютный риск – на 43,3% по сравнению с группой «Опыт 1». Данные гистоморфологического исследования свидетельствуют о формировании в центральной зоне дефекта гиалинового хряща, местами максимально приближенного к интактному хрящу с обозначением зональности.Заключение. Результаты исследования разработанной трехмерной клеточно-инженерной конструкции, состоящей из мезенхимальных стволовых клеток костного мозга, выращенных на проницаемой коллагеновой матрице «Остеопласт», демонстрируют формирование в области ее имплантации хрящевой гиалиновой ткани с высокой степенью структурной организации. Вновь образованный хрящ лишь незначительно уступает по толщине предсуществующей хрящевой ткани, что способствует динамическому распределению осевой нагрузки по суставной поверхности и в совокупности позволяет надеяться на хорошие долгосрочные результаты. Таким образом, на основании полученных данных считаем обоснованным проведение следующих этапов исследования предложенной клеточно-инженерной конструкции для хондропластики ограниченных дефектов суставного хряща.