Access Of Oxygen Research Articles

The influence of heating on the carbon isotope composition, organic geochemistry and petrology of coal from the Upper Silesian Coal Basin (Poland): An experimental and field study

The impact of natural intra-deposit heating on the δ13C signature, organic geochemistry, and petrology of coal and coal-bearing rocks characterised by various degrees of coalification and palaeoenvironments in the Upper Silesian Coal Basin, Poland, is elaborated. Reconstruction of palaeofire performed by heating experiments up to 400 °C in open and semi-closed systems with different heating regimes confirms the crucial significance of temperature and oxygen access. In open-system heating, released 13C-depleted gases enrich residue coke in 13C compared to raw coal. Petrological examinations did not show the impact of palaeofires on the maceral properties of coal. However, the carried-out experiment caused the formation of devolatilisation pores, rounded edges, cracks, pale rims, as well as higher reflectance and paler colour that was what was expected. Extractable compounds become highly depleted, and low-weight organic compounds nearly absent. Relatively high contents of combustion-formed PAHs are an indicator of open-system heating. In semi-closed systems, the final total isotopic composition was almost unchanged as no components are carried away though changes in petrography and geochemistry occur. Increased extract yields reflect the release of bitumen from closed pores and partial pyrolysis of organic matter. Depletion of lighter n-alkane compounds, total carbon TC and volatiles decrease, and variable values of various alkyl aromatic hydrocarbon ratios are also indicative of semi-closed heating. Coal seams suspected of intra-deposit heating show geochemical and isotopic features similar to semi-closed- rather than open-system heating, and their δ13C signatures and organic geochemistry did not respond strongly during laboratory re-heating.

Palladium-based oxygen scavenger for food packaging: Choosing optimal hydrogen partial pressure

Several packaging solutions for the food industry have to consider the harmful effects of oxygen within a pack for packaging of oxygen sensitive foods. This issue can be addressed by using oxygen scavengers. However, in adverse cases, conventional oxygen scavengers react too slowly to reduce the access of oxygen to sensible foods. Therefore, several alternative approaches for oxygen scavengers are in focus right now. In this work, an oxygen scavenger system based on vacuum-deposited palladium (Pd) on PET films was tested. Pd catalyzes the reaction of headspace oxygen, remaining in food packages, with hydrogen. The hydrogen can be provided by modified atmosphere packaging. To improve the substrate surface, an additional silicon oxide (SiOx) layer was applied to the films before Pd deposition. To determine the oxygen-scavenging activity, the Pd-metalized films were placed into airtight cells. These cells were flushed with a gas mixture containing 95 vol.-% nitrogen and 5 vol.-% hydrogen. Defined amounts of oxygen were injected into the cells. The kinetic parameters of Pd-metalized films were determined as a function of hydrogen and oxygen partial pressures and area of Pd-coated film. The effect of different cover films on Pd on the reaction rate was analyzed, too. By the results was shown that the oxygen-scavenging rate is strongly dependent on the proportion of hydrogen to oxygen. The oxygen-scavenging rate increases with a decreasing ratio of hydrogen to oxygen (with ratio 2.5:1 as the fastest tested condition). However, there has to be a sufficient hydrogen excess inside the headspace to reach overall highest oxygen-scavenging capacity (ratio up to 10.6:1 tested). For practical application in food packaging, it is important to adjust the hydrogen concentration in modified atmosphere packaging to residual oxygen present in packaging, to choose a sufficient area of Pd-metalized film as well as suitable cover film with high oxygen permeance. This publication provides recommendations for this purpose.

Extinguishing Petroleum Vapor Intrusion and Methane Risks for Slab‐on‐ground Buildings: A Simple Guide

AbstractThe occurrence of aerobic biodegradation in the vadose zone between a subsurface source and a building foundation can all‐but eliminate the risks from methane and petroleum vapor intrusion (PVI). Understanding oxygen availability and the factors that affect it (e.g., building sizes and their distribution) are therefore critical. Uncovered ground surfaces allow oxygen access to the subsurface to actively biodegrade hydrocarbons (inclusive of methane). Buildings can reduce the net flux of oxygen into the subsurface and so reduce degradation rates. Here we determine when PVI and methane risk is negligible and/or extinguished; defined by when oxygen is present across the entire sub‐slab region of existing or planned slab‐on‐ground buildings. We consider all building slab sizes, all depths to vapor sources and the effect of spacings between buildings on the availability of oxygen in the subsurface. The latter becomes critical where buildings are in close proximity or when increased building density is planned. Conservative assumptions enable simple, rapid and confident screening should sites and building designs comply to model assumptions. We do not model the aboveground “building” processes (e.g., air exchange), and assume the slab‐on‐ground seals the ground surface so that biodegradation of hydrocarbons is minimized under the built structure (i.e., the assessment remains conservative). Two graphs represent the entirety of the outcomes that allow simple screening of hydrocarbon vapors based only on the depth to the source of vapors below ground, the concentration of vapors within the source, the width of the slab‐on‐ground building, and the gap between buildings; all independent of soil type. Rectangular, square, and circular buildings are considered. Comparison with field sites and example applications are provided, along with a simple 8‐step screening guide set in the context of existing guidance on PVI assessment.

Differences in the properties of porcine cortical and nuclear fiber cell plasma membranes revealed by saturation recovery EPR spin labeling measurements

Eye lens membranes are complex biological samples. They consist of a variety of lipids that form the lipid bilayer matrix, integral proteins embedded into the lipid bilayer, and peripheral proteins. This molecular diversity in membrane composition induces formation of lipid domains with particular physical properties that are responsible for the maintenance of proper membrane functions. These domains can be, and have been, effectively described in terms of the rotational diffusion of lipid spin labels and oxygen collision with spin labels using the saturation recovery (SR) electron paramagnetic resonance method and, now, using stretched exponential function for the analysis of SR signals. Here, we report the application of the stretched exponential function analysis of SR electron paramagnetic resonance signals coming from cholesterol analog, androstane spin label (ASL) in the lipid bilayer portion of intact fiber cell plasma membranes (IMs) isolated from the cortex and nucleus of porcine eye lenses. Further, we compare the properties of these IMs with model lens lipid membranes (LLMs) derived from the total lipids extracted from cortical and nuclear IMs. With this approach, the IM can be characterized by the continuous probability density distribution of the spin-lattice relaxation rates associated with the rotational diffusion of a spin label, and by the distribution of the oxygen transport parameter within the IM (i.e., the collision rate of molecular oxygen with the spin label). We found that the cortical and nuclear LLMs possess very different, albeit homogenous, spin lattice relaxation rates due to the rotational diffusion of ASL, indicating that the local rigidity around the spin label in nuclear LLMs is considerably greater than that in cortical LLMs. However, the oxygen transport parameter around the spin label is very similar and slightly heterogenous for LLMs from both sources. This heterogeneity was previously missed when distinct exponential analysis was used. The spin lattice relaxation rates due to either the rotational diffusion of ASL or the oxygen collision with the spin label in nuclear IMs have slower values and wider distributions compared with those of cortical IMs. From this evidence, we conclude that lipids in nuclear IMs are less fluid and more heterogeneous than those in cortical membranes. Additionally, a comparison of properties of IMs with corresponding LLMs, and lipid and protein composition analysis, allow us to conclude that the decreased lipid-to-protein ratio not only induces greater rigidity of nuclear IMs, but also creates domains with the considerably decreased and variable oxygen accessibility. The advantages and disadvantages of this method, as well as its use for the cluster analysis, are discussed.

Performance evaluation of venturi aeration system

The venturi aeration is an effective practice to increase the dissolved oxygen accessibility in the water bodies. This study aims to optimize the various geometrical parameters of the venturi aeration system. A non-dimensional technique was applied to find the optimum performance of various geometric parameters i.e. throat lengths (tl), number of air holes (N), and converging and diverging angles (α and β). These experiments have been carried out using 1124 L capacity of tank having dimensions of 105 cm long, 105 cm wide and 102 cm deep. The experiments were conducted at a constant flow velocity of water (1.096 m/s) with varying throat length (tl = 20–100 mm keeping 20 mm as interval between two consecutive length), number of air holes (N = 1–17 at an equal hole to hole distance of 5 mm between them), and converging and diverging angles (α and β = 10°, 15°, 20° and 25°). Multiple non-linear regression equations were also developed from the linear relation with the dependent variable (Non-dimensional form of standard aeration efficiency, NDSAE) and independent variables (tl and N). With the geometrically optimized venturi aerator the optimum performance was found for tl =100 mm, N = 17, and α and β = 15°. The maximum value of standard oxygen transfer rate (SOTR) and standard aeration efficiency (SAE) obtained was 0.0216 kgO2/h and 0.611 kgO2/kWh respectively. From the non-dimensional study, it was found that the NDSAE is the function Reynolds number (Re) and Froude number (Fr). The simulation equations were developed on the basis of Re and Fr for NDSAE, and subjected to 7.378 × 10−6 <Re < 3.689 × 10-5 and 0.163 <Fr < 0.817, respectively.

The effect of hypoxia-mimicking responses on improving the regeneration of artificial vascular grafts

Cellular transition to hypoxia following tissue injury, has been shown to improve angiogenesis and regeneration in multiple tissues. To take advantage of this, many hypoxia-mimicking scaffolds have been prepared, yet the oxygen access state of implanted artificial small-diameter vascular grafts (SDVGs) has not been investigated. Therefore, the oxygen access state of electrospun PCL grafts implanted into rat abdominal arteries was assessed. The regions proximal to the lumen and abluminal surfaces of the graft walls were normoxic and only the interior of the graft walls was hypoxic. In light of this differential oxygen access state of the implanted grafts and the critical role of vascular regeneration on SDVG implantation success, we investigated whether modification of SDVGs with HIF-1α stabilizer dimethyloxalylglycine (DMOG) could achieve hypoxia-mimicking responses resulting in improving vascular regeneration throughout the entirety of the graft wall. Therefore, DMOG-loaded PCL grafts were fabricated by electrospinning, to support the sustained release of DMOG over two weeks. In vitro experiments indicated that DMOG-loaded PCL mats had significant biological advantages, including: promotion of human umbilical vein endothelial cells (HUVECs) proliferation, migration and production of pro-angiogenic factors; and the stimulation of M2 macrophage polarization, which in-turn promoted macrophage regulation of HUVECs migration and smooth muscle cells (SMCs) contractile phenotype. These beneficial effects were downstream of HIF-1α stabilization in HUVECs and macrophages in normoxic conditions. Our results indicated that DMOG-loaded PCL grafts improved endothelialization, contractile SMCs regeneration, vascularization and modulated the inflammatory reaction of grafts in abdominal artery replacement models, thus promoting vascular regeneration.

Assembly and Disassembly of the Micropatterned Collagen Sheets Containing Cells for Location-Based Cellular Function Analysis

The liver has complex microenvironments, where parenchymal hepatocytes and non-parenchymal cells coexist. Hepatocytes exhibit different metabolic functions depending on their location by the oxygen gradient and the transcriptional changes of genes, which is called liver zonation. Three-dimensional (3D) liver tissue engineering has reproduced the complex microenvironments, but there is a limitation in analyzing them by location. In this study, a novel 3D tissue-level hepatic cell culture platform is developed via stacking the manipulable collagen sheets to spatially analyze the reconstructed metabolic zonation. The controlled assembly of the sheets containing hepatocytes and endothelial cells, respectively, creates a 3D co-culture environment that improves hepatic function. In addition, the sheet micropatterning can be used to control the accessibility of oxygen and nutrients in the stacked sheets. The disassembly of the stacked sheets enables a layer-by-layer analysis and allows us to confirm the metabolic zonation qualitatively. A demonstration of acetaminophen-induced liver injury using the stacked sheets shows the improved drug sensitivity by co-culture and chemical induction and presents the quantitative results of the different cellular responses to the drug by layers according to metabolic zonation. Therefore, this platform is expected to be used for an in-depth analysis of drug toxicity in complex tissues via spatial analysis.

ТЕХНИКО-ТЕХНОЛОГИЧЕСКОЕ ИЗУЧЕНИЕ КЕРАМИКИ 1-Й ПОЛОВИНЫ XX В. С ТЕРРИТОРИИ ТАБУНСКОГО РАЙОНА АЛТАЙСКОГО КРАЯ

The article is devoted to the publication ofmaterials of a technical and technological analysis of ceramics discovered on four nowadays non-existent settlements, founded during the Stolypin reforms, on the territory of the modern Tabunsky district of the Altai region. As a result of the study, it was found that ceramic products from clays of medium and strong ferrous content, of various plasticity prevailed there. Three recipes for molding materials have been founded. Most of the products were fired at high temperatures with oxygen access. Most of the crockery were not subjected to additional surface treatment; glazed items are also found, one vessel was ornamented. The data obtained agree with the available written and ethnographic sources. Further work on the technical and technological analysis of “Russian” ceramics, as well as conducting archaeological and ethnographic research, can provide more complete information about the level of development of pottery production in Altai, as well as reveal the specifics and local features of different districts. Keywords: pottery, ceramics, first half of the 20th century, altai, technical and technological analysis

Структура популяции Gluconacetobacter hansenii GH 1/2008 в статической культуре на различных источниках углерода

Структура популяции Gluconacetobacter hansenii GH 1/2008 в статической культуре на различных источниках углерода

Influence of abiotic factors on seed quality of maize hybrids in the process of its storage

The research results of influence of various abiotic factors on seed quality of maize hybrids during long storage are given. The most effective of them are: temperature regime, seed moisture content and oxygen access. The storage methods (dry and cold, and controlled atmosphere storage) that have the greatest impact on the seed quality were established. It was found that the optimal moisture content of seed depends on the storage duration, if for 1–2 years – 10–11 %, 3 years and more – 7–8 %. In order to stabilize the moisture content, it is recommended to store the seeds in airtight containers, limiting the humidity access from the outside. During the long-term seed storage, particularly for the breeding purposes, the temperature range should advisably maintain within 8–10 °C in seed storage place. With that the laboratory germination of seeds increased by 3–5 %, field germination – by 6–8 %, growth rate by number of sprouts– by 5–9 % and by the weight of sprouts – by 2–5 g compared to the 18–20 °C temperature in a typical storage. Methods of pre-sowing improvement of seed quality were established – it is separation and chemical treatment (seed dressing). Separation is the sifting of the seed mass through sieves with round holes in order to divide from the smallest fraction, the content of which was 15–23 % depending on the seed uniformity of maize hybrids. It was found that in order to assess objectively the effectiveness of different chemicals and establish their suitability for presowing seed treatment, it is necessary to determine laboratory germination, especially the growth rate by the number of sprouts and weight of 100 sprouts. Premature chemical treatment of seed should be avoided. Key words: maize hybrids, storage methods, abiotic factors, seed quality, presowing treatment.

Дослідження зв’язку між кінетикою окиснення та погіршенням сенсорних характеристик рослинних олій

The article investigates the possibility of predicting the appearance of a feeling of rancidity by the main indicators of oil oxidation – peroxide and anisidine numbers. As a result of oxidation at 28 ° C and the access of air oxygen, significant amounts of hydroperoxides (up to 160-180 mmol 1/2O/kg) accumulated, but the feeling of rancidity did not appear. It is proved that according to the kinetics of oils oxidation according to the data of anisidine numbers, it is possible to predict the moment of deterioration of the organoleptic characteristics of oils. Key words: oxidation, rancidity, vegetable oils, anisidine number, aldehydes, peroxide number, hydroperoxides.

Structure and strength characteristics of rutile ceramics obtained with the approach of oxidative constructing

As a result of applying the oxidative constructing approach, compact samples of rutile ceramics were obtained at 875°C for 160 days. An analysis of the distribution of microhardness over the thickness of a rutile sample obtained at 875°C at different times of synthesis indicates an inhomogeneous structure of rutile ceramics, which indicates that the material is defective due to its porosity. The regularities of changes in the nature of the layering of the structure of ceramics are established depending on the portion of the kinetic curve of the direct oxidation of titanium. It is shown that the presence of a defect in the form of a gap between the layers formed during the oxidation of titanium blanks at the stage of completion of the exponential growth of the kinetic curve is due to a natural barrier – a massive rutile ceramic layer, which limits the free access of oxygen to the TiO2/Ti interface.

Моделювання процесів фазоутворення на поверхні сталі при її контакті з водним середовищем за умов глибинного геологічного сховища

The experimental modeling of the corrosive phase formation processes was performed under conditions approaching the initial and transitional stages of evolution of the deep geological repository (the hydrogen index of the medium lied in the range of 9–12 and a temperature was 50–70 °C). The specificity of the system of rotating disk electrode made it possible to determine the phase composition of corrosion products formed under oxidative conditions (the near surface layer, NSL) and, conditionally, reductive — on the steel surface (SL) covered by NSL, that significantly complicated the access of oxygen into the reaction area. It was determined that phase composition of the corrosion products at the pH0 values 9–11 was identical and it is regulated by the compensative action of cathodic half-reaction of oxygen reducing on the steel surface. Green Rust and magnetite or non-stoichiometric spinel ferrite characterized by coagulative type of the structure and spherical particle shape were determined as the main phases of SL. Iron oxyhydroxides — goethite and lepidocrocite were presented as the phases of NSL. Increase in the pH0 to 12 changes the chemical mechanism of the corrosion process and it leads to the formation of weak crystallized iron oxyhydroxide phases. It was proved the main phase formed under corrosion of steel at 50–70 °C was spinel ferrite. Its morphology is presented as the cubic shaped particles that evidences about condensingcrystallizing mechanism of their formation. Generally, the presence of Co2+ and Mn2+ cations does not influence on the phase formation process and the phase composition as well, whereas the iron oxyhydroxides with admixture of Mn2+ and Mn3+ oxygen compounds are dominant in the sediment compositions when they are formed in the presence of Mn7+.

Експериментальне дослідження розвитку пожежі в будівлі

Experimental studies on the occurrence of fire in a residential building depending on the conditions of its development. A model of the house was used for research, which allowed to clearly demonstrate the development of fire with a demonstration of its phenomena. It is determined that the development of a fire with limited access to oxygen occurs with the occurrence of fire phenomena such as rollover, flashover and backdraft, and with sufficient access to oxygen occurs normally. It is established that during the development of a fire first there is a phenomenon of rollover, due to the ignition of a layer of heated gases, then there is a flashover, characterized by a flash, and for backdraft, this phenomenon occurs due to a flash of unburned heated gases with a subsequent explosion. The temperature was measured using a FLIR K33 thermal imager during a fire. The obtained results show that the development of a fire with sufficient access of oxygen occurs before the maximum temperature in the room with its subsequent reduction due to fire extinguishing or supply of fire extinguishing agents to the fire. When a fire with limited access to oxygen develops, such phenomena as rollover, flashover and backdraft occur. The obtained measurement results during the research of fire development depending on its conditions are presented as photoregistration of images from the thermal imager and graphically. It is established that when the phenomenon of a flashover occurs, the flash point is 234 C, and when the backdraft phenomenon, the flash point of unburned heated gases with a subsequent explosion is 569 C. It has been experimentally determined that timely cooling of heated gases prevents fire. The obtained results of the conducted experimental researches allow to increase the level of professional skill of the personnel of fire and rescue divisions during carrying out operative actions on fire extinguishing in residential buildings.

Abdominal adhesions: Surgical treatment and prevention (literature review)

The ongoing discussion on the diagnosis and tactics of surgical treatment of painful forms of adhesions of the abdominal cavity and adhesive intestinal obstruction testifies to the persistent urgency of this problem. The presence of a postoperative scar and recurrent abdominal pain are interpreted by surgeons and gastroenterologists as adhesive disease, with the appointment of the same type of treatment. At the same time, patients have a reduced critical attitude to their condition, which leads them to late seeking medical help. For the occurrence of the adhesion process, a long-term effect of a complex of factors is necessary, an important place among which is blood supply, oxygen access to tissues and peristalsis in the early postoperative period. The most effective methods of treatment and prevention of intestinal obstruction are low-traumatic surgical technologies. There was no statistically significant difference between open and laparoscopic adhesiolysis in the number of intraoperative intestinal injuries, wound infections and mortality. Laparoscopic operations have fewer general and pulmonary complications than open ones. Reducing fibroblast proliferation, minimizing hypoxia and inflammation are a new preventive solution to the problem of adhesion formation.

PROCESSING OF WASTE COAL FINES WITHOUT ACCESS TO OXYGEN

The subject of research in this work is the processing of waste coal fines using a pyrolysis plant. The aim of the study is to obtain semi-coke and pyrolysis gas in the process of processing waste coal fines without oxygen. The process of thermochemical processing of coal fines is carried out by the principle of embedding a pyrolysis unit in a pyrolysis unit, or a second pyrolysis unit of a reduced size is installed inside the improved design of the pyrolysis unit using a specially withdrawn hole. To obtain the result of the study, the main pyrolysis unit, first, we will load the main pyrolysis unit with coal and then install the built-in (new) pyrolysis unit by preloading it with coal fines, and then we will make connections with the outlet pipe and fully load the main pyrolysis unit. We attach a distributor tee, a waste material container and a receiver for collecting pyrolysis gas to the outlet pipe. Experimental research is carried out on the coals of the Abshyr-ata and Kozho-kelen deposits, and for the reliability of the obtained research result, we will measure the main parameters of the studied coals until the final product is obtained. To obtain the result of the study, the main pyrolysis unit, first, we will load the main pyrolysis unit with coal and then install the built-in (new) pyrolysis unit by reloading it with coal fines, and then we will make connections with the outlet pipe and fully load the main pyrolysis unit. We attach a distributor tee, a waste material container and a receiver for collecting technical gas to the outlet pipe. Experimental research is carried out with coals of the Abshyr-ata and Kozho-kelen brands, and for the reliability of the obtained research result, we will measure the main parameters of the studied coal grades until the final product is obtained. With the help of this unit, the process of upgrading waste of coal fines and low-grade coals of Kyrgyzstan is carried out. The developed installation can be used in the heat and power industry of the Republic and research institutions.

ЕКОЛОГО-ГІГІЄНІЧНІ АСПЕКТИ ФУНКЦІОНУВАННЯ ПІДПРИЄМСТВ-СУБ’ЄКТІВ ГОСПОДАРЮВАННЯ В СФЕРІ ПОВОДЖЕННЯ З ВІДХОДАМИ ІЗ ЗАСТОСУВАННЯМ ТЕРМІЧНИХ МЕТОДІВ

Objective. Sanitary and hygienic assessment of the conditions of safe operation of enterprises using equipment for thermal disposal / waste disposal. Materials and methods. The objects of research were enterprises where waste is subjected to thermal disposal/utilization (location of production facilities – Odessa and Dnipropetrovsk regions). To conduct a sanitary and hygienic assessment of the levels of impact created at the border of the sanitary protection zone (SPZ) of production, the results of instrumental studies of air samples, acoustic measurements, and the results of calculating the scattering of gross pollutant emissions from their emission sources were analyzed. form the total gross emission at the industrial site (research protocols were provided by certified laboratories), as well as regulatory and technical documentation, according to which the company operates. Results. The main processes that determine the hazard class of enterprises are thermal, namely: disposal of hazardous waste at the installation for thermal disposal (utilizer) type UT3000D and processing (utilization) of rubber products by pyrolysis at the unit UE GTV MTD-5/24. The utilizer includes a combustion chamber of exhaust gases at a temperature up to 1300˚C and is equipped with a two-stage system for their purification. Shredded rubber-containing waste is pyrolyzed at a temperature of 450°C without access of oxygen with the formation of secondary waste (carbon residue, metal cord residues, gas fraction, which is burned in the main chamber, furnace fuel), which are transferred to consumers on contractual terms. As in the classification of productions [2] such enterprises are absent, SPZ for the enterprise with the utilizer UT3000D is defined in the size of 500 m by analogy with garbage incineration, for the enterprise where pyrolysis is applied - SPZ is established at the size of 110 m (on the border of the nearest inhabited building). According to the results of field research, no exceedances of the normative indicators were detected for any pollutant at the border of the SPZ. Conclusions. The conditions for the operation of enterprises are not exceeding the hygienic regulations of the permissible content of chemicals in the air of settlements [3] and ensuring the regulatory level of acoustic impact at the SPZ in accordance with the requirements [2,4], compliance with technological regulations on waste management, safety rules and use of overalls, footwear and personal protective equipment when working with hazardous waste, as well as determining the hazard class of secondary waste generated in the process of thermal disposal / utilization.

Selection of Effective Therapies Using Three-Dimensional in vitro Modeling of Chondrosarcoma.

Purpose: Chondrosarcomas are a group of cartilaginous malignant neoplasms characterized by the deposition of chondrogenic extracellular matrix. Surgical resection is currently the only curative treatment option, due to their high resistance to conventional chemotherapy and radiotherapy. Novel therapeutic treatment options may improve outcome. Predominantly used cell line monolayer in vitro models lack in vivo complexity, such as the presence of extracellular matrix, and differing oxygen access. Hence, we aimed to improve pre-clinical chondrosarcoma research by developing an alginate-based 3D cell culture model.Method: An alginate scaffold was applied to generate spheroids of three chondrosarcoma cell lines (CH2879, JJ012, SW1353). Morphological, histological and immunohistochemical assessment of the spheroids were used to characterize the chondrosarcoma model. Presto blue assay, morphological and immunohistochemical assessment were applied to assess spheroid response to a panel of chemotherapeutics and targeted therapies, which was compared to conventional 2D monolayer models. Synergistic effect of doxorubicin and ABT-737 (Bcl-2 inhibitor) was compared between monolayer and spheroid models using excess over Bliss. A 3D colony formation assay was developed for assessment of radiotherapy response.Results: Chondrosarcoma spheroids produced chondrogenic matrix and remained proliferative after 2 weeks of culture. When treated with chemotherapeutics, the spheroids were more resistant than their monolayer counterparts, in line with animal models and clinical data. Moreover, for sapanisertib (mTOR inhibitor) treatment, a recovery in chondrosarcoma growth, previously observed in mice models, was also observed using long-term treatment. Morphological assessment was useful in the case of YM-155 (survivin inhibitor) treatment where a fraction of the spheroids underwent cell death, however a large fraction remained proliferative and unaffected. Synergy was less pronounced in 3D compared to 2D. A 3D clonogenic assay confirmed increased resistance to radiotherapy in 3D chondrosarcoma spheroids.Conclusion: We demonstrate that the chondrosarcoma alginate spheroid model is more representative of chondrosarcoma in vivo and should be used instead of the monolayer model for therapy testing. Improved selection at in vitro stage of therapeutic testing will increase the amount of information available for experimental design of in vivo animal testing and later, clinical stages. This can potentially lead to increased likelihood of approval and success at clinical trials.

Generation and long-term culture of advanced cerebral organoids for studying later stages of neural development.

Cerebral organoids, or brain organoids, can be generated from a wide array of emerging technologies for modeling brain development and disease. The fact that they are cultured in vitro makes them easily accessible both genetically and for live assays such as fluorescence imaging. In this Protocol Extension, we describe a modified version of our original protocol (published in 2014) that can be used to reliably generate cerebral organoids of a telencephalic identity and maintain long-term viability for later stages of neural development, including axon outgrowth and neuronal maturation. The method builds upon earlier cerebral organoid methodology, with modifications of embryoid body size and shape to increase surface area and slice culture to maintain nutrient and oxygen access to the interior regions of the organoid, enabling long-term culture. We also describe approaches for introducing exogenous plasmid constructs and for sparse cell labeling to image neuronal axon outgrowth and maturation over time. Together, these methods allow for modeling of later events in cortical development, which are important for neurodevelopmental disease modeling. The protocols described can be easily performed by an experimenter with stem cell culture experience and take 2-3 months to complete, with long-term maturation occurring over several months.

Fire safety in tanks of oil and oil products storage

Formulation of the problem. The design of tank farms, providing them with fire protection and actions of fire and rescue units during fires or emergencies at such facilities are regulated by a number of regulations, despite the strict fire safety measures at these facilities, the number of fires in the parks storage of oil and oil products has remained unchanged for the last decades. Purpose of the article – is to develop on the basis of modernization of the existing system of fire protection of tank farms a methodology of automated water supply system for cooling tanks and formation of a fire-resistant self-tightening film for fire extinguishing with the help of a foam generator. Conclusion. The proposed sublayer fire extinguishing system provides rapid fire extinguishing by forming a fire-resistant self-tightening film on the surface of the oil product by floating in the upper part of small bubbles of low-density foam, blocking the access of oxygen to the combustion zone. The use of permanently installed in the upper belt of the tank pipelines for intensive water cooling of its walls in the event of a fire allows you to automatically perform water cooling of the tank walls without the use of gun barrels. The application of the proposed measures for fire localization makes it possible to reduce the damage from the fire by about 30… 36% compared to the generally accepted approach. The system of fire safety of facilities with the presence of petroleum products must contain a set of measures that exclude the possibility of not exceeding the values of the permissible fire risk and aimed at preventing the danger of fire and creating conditions for its successful extinguishing.