Changes In Oxygen Concentration Research Articles

A multilayer microfluidic system for studies of the dynamic responses of cellular proteins to oxygen switches at the single-cell level.

Oxygen levels vary in the environment. Oxygen availability has a major effect on almost all organisms, and oxygen is far more than a substrate for energy production. However, less is known about related biological processes under hypoxic conditions and about the adaptations to changing oxygen concentrations. The yeast Saccharomyces cerevisiae can adapt its metabolism for growth under different oxygen concentrations and can grow even under anaerobic conditions. Therefore, we developed a microfluidic device that can generate serial, accurately controlled oxygen concentrations for single-cell studies of multiple yeast strains. This device can construct a broad range of oxygen concentrations, [O2] through on-chip gas-mixing channels from two gases fed to the inlets. Gas diffusion through thin polydimethylsiloxane (PDMS) can lead to the equilibration of [O2] in the medium in the cell culture layer under gas cover regions within 2min. Here, we established six different and stable [O2] varying between ~0.1 and 20.9% in the corresponding layers of the device designed for multiple parallel single-cell culture of four different yeast strains. Using this device, the dynamic responses of different yeast transcription factors and metabolism-related proteins were studied when the [O2] decreased from 20.9% to serial hypoxic concentrations. We showed that different hypoxic conditions induced varying degrees of transcription factor responses and changes in respiratory metabolism levels. This device can also be used in studies of the aging and physiology of yeast under different oxygen conditions and can provide new insights into the relationship between oxygen and organisms. Integration, innovation and insight: Most living cells are sensitive to the oxygen concentration because they depend on oxygen for survival and proper cellular functions. Here, a composite microfluidic device was designed for yeast single-cell studies at a series of accurately controlled oxygen concentrations. Using this device, we studied the dynamic responses of various transcription factors and proteins to changes in the oxygen concentration. This study is the first to examine protein dynamics and temporal behaviors under different hypoxic conditions at the single yeast cell level, which may provide insights into the processes involved in yeast and even mammalian cells. This device also provides a base model that can be extended to oxygen-related biology and can acquire more information about the complex networks of organisms.

Effects of refining slag basicity and vacuum treatment on the cleanliness of bearing steel

The effect of vacuum treatment on the cleanliness of low Ti steel treated with low basicity refining slag was studied by analyzing the change of oxygen content and inclusions characteristics in the steel after the interaction between different basicity slags and GCr15 bearing steels and after vacuum treatment. The results show that the oxide inclusions in the steel are mainly MgO·Al2O3 after slag-steel interaction. The low basicity slag refining is beneficial for decreasing the harm of TiN inclusions due to the better low Ti content control. However, the oxygen content and the number of inclusions in the steel increase with the decrease of slag basicity (CaO/SiO2 mass ratio), which means that the decrease in the basicity is disadvantageous to the cleanliness of steel. Typical inclusions in the steel transform into smaller MgO inclusions and MgS–MgO-(MnS) composite inclusions after vacuum treatment, and the oxygen content of steel is decreased to the same level. Furthermore, the size and number density of inclusions are significantly decreased after the vacuum treatment. It indicates that the combined process of low basicity slag refining and vacuum carbon deoxidation can realize the TiN inclusion control and cleanliness improvement of GCr15 bearing steel.

Tracking and recording of intracellular oxygen concentration changes in cell organelles: preparation and function of azide-modified fluorescent probes.

Tracking hypoxic environments and changes in oxygen levels contribute to the elucidation of pathological mechanisms. In this study, we attempted to design molecular probes that can be activated to show fluorescence under hypoxic conditions and that can move to specific cell organelles. Considering that azide groups were selectively reduced to primary amines by reductases under hypoxic conditions, we prepared Hoechst and fluorophore Cy-5 derivatives with azide groups (Hoechst-N3 and Cy-N3) as hypoxia probes. Hoechst-N3 and Cy-N3 showed weak fluorescence, but once activated in the cytosol of hypoxic cells, they exhibited robust fluorescence and then moved to their target organelles, the cell nucleus and mitochondria. In addition, when these probes were administered to the cells in the proper sequence, each probe was activated in response to the intracellular oxygen concentration at that point and exhibited oxygen concentration-dependent fluorescence at the target organelle. By measuring the fluorescence intensity of the cell nucleus and mitochondria, we successfully traced the history of changes in intracellular oxygen levels. Thus, we achieved tracking and recording of oxygen status in the cells.

Analysis of mixed rhythm and its dynamics in closed-loop respiratory control system driven by electromagnetic induction

The pre-Bötzinger complex is a crucial region for generating respiratory rhythms in mammals. Peripheral chemoreceptors have a significant influence on respiratory rhythm by monitoring changes in blood oxygen concentration and carbon dioxide concentration. This study introduces a closed-loop respiratory control model, which is driven by electromagnetic induction and based on the activation of pre-Bötzinger complex neurons. The model incorporates various factors including the motor pool, lung volume, lung oxygen, blood oxygen, and chemoreceptors. The response of the system subjected to the same hypoxic perturbation under different electromagnetic induction is studied, and the control effect of magnetic flux feedback coefficient on the recovery of mixed rhythms is investigated. Using bifurcation analysis and numerical simulations, it is found that the magnetic flux feedback coefficient has a significant influence on the ability to recover respiratory rhythm. The dynamic mechanism of the magnetic flux feedback coefficient on different hypoxic responses in closed-loop systems are revealed. Dynamic analysis indicates that under certain electromagnetic induction, the mixed bursting rhythm in the closed-loop system can autoresuscitate if the bifurcation structure before and after applying hypoxia perturbation are completely identical. However, when the bifurcation structure before and after applying hypoxia perturbation are different, the mixed bursting rhythm in the system cannot autoresuscitate. In addition, for the cases where automatic recovery is not achieved under mild electromagnetic induction, increasing the magnetic flux feedback coefficient appropriately can lead the system to autoresuscitate, which is closely related to the Hopf bifurcation and fold bifurcation of limit cycle. This study contributes to understanding the influence of the interaction between the central respiratory and peripheral chemoreceptive feedback on respiratory rhythm, as well as the control effect of external induction on the hypoxic response.

Geochemical insights into secular changes in the depositional environment of ferromanganese nodules in the western North Pacific

Understanding Earth's surface dynamics and biological evolution requires deciphering past marine environmental changes. Hydrogenetic ferromanganese nodules formed by the direct precipitation of Fe–Mn oxide/hydroxide from seawater could record the marine environment at the time of deposition, as in the case of ferromanganese crusts. In this study, petrological and geochemical analyses were conducted on ferromanganese nodules collected from the Japanese Exclusive Economic Zone around Minamitorishima Island in the western North Pacific Ocean. Additionally, the results were compared with those of ferromanganese crusts distributed in the same area to elucidate the secular changes in the depositional environment. The mineralogical features (consisting solely of Fe-vernadite with an absence of 10 Å Mn oxide) and the geochemical characteristics (including positive Ce-anomaly and negative Y-anomaly in rare-earth element patterns, high Co contents, and low Cu and Ni contents) of the nodules suggest that the studied nodules are of a hydrogenetic origin. From the inside to the outside of the nodule, the Mn/Fe and Y/Ho ratios decrease while the Th/U ratio increases, indicating a changing depositional environment over time. A similar trend was observed in ferromanganese crusts from the nearby Takuyo-Daigo Seamount. Furthermore, similar compositional changes were observed on the surfaces of the crust samples (uppermost 1–3 mm), which correlated with depth-related changes in seawater oxygen concentrations. Therefore, the observed cross-sectional changes in the chemical compositions of the nodules and crusts may reflect changes in seawater-dissolved oxygen concentrations over time. The Mn/Fe and Y/Ho trends indicate a shift towards a less oxic environment with increasing age while maintaining the current depth profile, implying an expansion of the oxygen minimum zone (OMZ). Moreover, the observed Ni and Cu enrichment, together with the changes in the Mn/Fe and Y/Ho ratios, suggest that the expansion of the OMZ was caused by increased surface ocean productivity.

Neural mechanisms of intertemporal and risky decision-making in individuals with internet use disorder: A perspective from directed functional connectivity.

The intertemporal and risk decision-making impairments are vital cognitive mechanisms in internet use disorder (IUD). However, the underlying neural mechanisms for these two decision-making dysfunctions in individuals with IUD remain unclear. This study employed Functional Near-Infrared Spectroscopy (fNIRS) to record changes in blood oxygen concentration in the prefrontal cortex of individuals with IUD during intertemporal and risk decision-making tasks. The findings revealed that the intertemporal decision-making deficits in IUD group were primarily associated with reduced activation in the left dorsolateral prefrontal cortex (dlPFC) and orbitofrontal cortex (OFC) and FC from the left dlPFC to the right dlPFC. On the other hand, risk decision-making impairments were linked to decreased OFC activation and weakened functional connectivity from the left dlPFC to the right dlPFC and OFC. These results suggested that while there were common neural mechanisms underlying intertemporal and risk decision-making impairments in individuals with IUD, specific neural foundations existed for each type of dysfunction.

Experimental study on the fragmentation behavior of coal particles during gasification process in drop-tube furnace

Studying the fragmentation characteristics of coal particles is important for enhancing furnace gasification efficiency. Based on the processing method of visualization imaging technology, this study investigated the proportion of particle fragmentation, fragmentation mode, surface temperature, and other characteristics of the Fuhua Indonesian Coal (FIC) gasification process at different temperatures and oxygen concentrations in a drop-tube furnace. The results show that the proportion of fragmentation at the center was higher than the proportion of fragmentation at the outer zone under experimental conditions. The most significant difference between the two phenomena was the length of the fragmentation period and the overall structural changes. The proportion of fragmentation at the center positively correlated with an increase in temperature and negatively correlated with an increase in oxygen concentration. Under high-temperature and low-oxygen concentration conditions, FIC tends to be in the high fragmentation mode. The temperature at the time of FIC fragmentation increased with increasing particle size. Compared with the temperature, the change in oxygen concentration had a more remarkable effect on the fragmentation temperature, specifically in the outer zone. Elevating the oxygen concentration and temperature both promoted particle fragmentation. Temperature had a greater effect on fragmentation in the outer zone, while fragmentation at the center was more sensitive to changes in oxygen concentration.

Effect of low pH on embryonic and larval traits in the estuarine semi-terrestrial crab Neohelice granulata

The decrease in the pH of the oceans is one of the consequences of the release of CO2 (carbon dioxide) into the atmosphere by human activities. In estuaries, the magnitude to which pH will change and how the organisms that inhabit these environments would be affected is today relatively poorly known. We evaluated, by two laboratory experiments, whether the low pH affects early stages of the semi-terrestrial crab Neohelice granulata, an estuarine and ecosystem engineer species. Firstly, embryos and the spawning larvae were exposed to acidified seawater (ambient pH: 7.9 and 8, respectively; 7.5 and 6.9); secondly, ovigerous females were collected from the field and freshly hatched larvae were cultured under these pHs. We found a slight delay in the development time of embryos exposed to pH 6.9 but no difference in those reared under intermedial pH (7.5) with respect to the control and 6.9. We also found a reduction in egg volume and eye size exposed at pH 7.5 but with a recovery to normal size later in development. Heartbeats did not vary with pH. A delay in the duration of the intermolt period was observed for both larvae zoea I (ZI) and II (ZII) exposed to pH 6.9 in the first experiment, and only in ZI under this pH in the second one. Differences in body morphometry were found in the zoeas analyzed in the first experiment but not for the second. Measurements of changes in oxygen concentration conducted in the second experiment showed a reduction in the consumption of all zoeae stages when exposed to both low pHs. Mortality of larvae remained constant across treatments. Although it was found that the early stages of this species would be slightly/moderately affected by potential future scenarios of pH decrease, we cannot rule out major impacts at the population level, which requires further experiments to be carried out.

Revisiting the relationship between the pore water carbon isotope gradient and bottom water oxygen concentrations

Reconstructing the oxygen content at the ocean floor provides insight into ocean circulation, ventilation, and carbon storage in the deep sea. The microbial breakdown of organic carbon within marine sediment through aerobic respiration consumes oxygen in the pore fluid and releases dissolved inorganic carbon. The offset in the carbon isotopic composition, δ13C, of epifaunal and infaunal foraminifera, Δδ13C, is considered to reflect the aerobic respiration of organic carbon and can be used to reconstruct the oxygen content of the bottom water. Previous work provided an empirical calibration that was suggested to be valid for oxygen reconstructions between 55 and 235 μmol kg−1. In this study, we apply a biogeochemical reactive transport model (RTM) to extend and update this calibration, allowing for the reconstruction of oxygen concentrations ([O2]) up to ∼300 μmol kg−1. Using the RTM and new bottom water [O2] and pore fluid measurements from Iberian Margin sediment cores, we also demonstrate that the calibration between the Δδ13C and bottom water [O2] must account for the coupled changes in the carbon system due to the respiration of organic carbon in the overlying ocean including the concentration and carbon isotopic composition of the dissolved inorganic carbon, and the δ13C of the organic carbon within the sediment column. We apply the improved calibration to reconstruct the changes in oxygen content at International Ocean Discovery Program (IODP) Site U1385 in the deep North Atlantic over the past 1.5 Myr.

Research on measurement error calibration method of TDLAS oxygen concentration detection based on CFD and SVR

Tunable Diode Laser Absorption Spectroscopy (TDLAS) enables rapid online detection of gas concentrations through the absorption of spectral lines by gas molecules in the infrared spectral region. In order to solve the problem of hysteresis and large errors of the measured values relative to the true values when TDLAS detects gases with simultaneous changes in oxygen concentration and flow rate in real-time, the CFD simulation model of the absorption cell is established by Fluent. The relationship between the measured value of TDLAS and the actual concentration change under different flow conditions is analyzed by simulation data, and the support vector machine regression calibration model is established to reduce the measurement error. It successfully reduces the average error from 5.844% to 2.899%, which is a reduction of 50.7%. The average error is further reduced to 1.308% after a secondary calibration based on different starting concentrations. The method is suitable for concentration detection in the presence of rapid changes in oxygen concentration.

Oxygen-driven divergence of marine group II archaea reflected by transitions of superoxide dismutases.

Reactive oxygen species (ROS), including superoxide anion, is a series of substances that cause oxidative stress for all organisms. Marine group II (MGII) archaea are mainly live in the surface seawater and exposed to considerable ROS. Therefore, it is important to understand the antioxidant capacity of MGII. Our research found that Fe/Mn- superoxide dismutase (Fe/MnSOD) may be more suitable for MGII to resist oxidative damage, and the changes in oxygen concentrations and SOD metallic cofactors play an important role in the selection of SOD by the 17 clades of MGII, which in turn affects the species differentiation of MGII. Overall, this study provides insight into the co-evolutionary history of these uncultivated marine archaea with the earth system.

Surface morphology and oxidation evolution of glow discharge polymer capsules during tumble polishing

Glow discharge polymer (GDP) capsules are often used as the ablation layer in laser inertial confinement fusion (ICF) research, because of its excellent properties in low X-ray opacity, high tensile strength, and high thermal conductivity. The isolated surface defects and distribution of oxygen content on the surface of GDP capsules can lead to the increase of hydrodynamic instability and the decrease of compression efficiency. In this work, by using media spheres and silica nanoparticles, a tumble polishing device for GDP capsule polishing is built to improve the surface morphology. The effects of polishing parameters on the surface roughness and oxygen content of GDP were investigated. The test results show that tumble polishing can effectively remove convex defects, only 24 identified defects with a height below 231 nm were found after 144 h polishing, reduce the surface roughness (∼10 nm) and improve the surface quality of GDP capsules. Moreover, the oxygen content distribution on the surface of GDP is uniform after tumble polishing. And the depth analysis results show that the tumble polishing has no obvious effect on the change of oxygen content in GDP shell under the surface layer.

From hydroxyl group to carbonyl group: Tuning the supercapacitive performance of holey graphene

Both hydroxyl group and carbonyl group are the inborn active sites on graphene for energy storage. However, it is difficult to distinguish the definite influence of these functional groups on the supercapacitive performance of graphene due to the considerable changes of total oxygen content (TOC) when adjusting the content of hydroxyl group and carbonyl group on graphene. In this paper, holey graphene was prepared by reoxidation method with ammonium persulfate as oxidant. During the reducing process, four kinds of reductant (formaldehyde, sodium borohydride, vitamin C and glucose) were used to optimize the TOC of graphene. Then, the directional tuning of the content of hydroxyl group and carbonyl group on graphene under a stable TOC was achieved by controlling the addition amount of specific reductant. Results from morphological and electrochemical analysis suggest that high carbonyl content leads to a fluffier graphene structure, bigger specific surface area, higher specific capacitance and lower ion diffusion resistance while high hydroxyl group content results in wider operating potential window and better electrical conductivity. After balancing the content of hydroxyl and carbonyl group in the holey graphene, the assembled supercapacitor owns the high energy density of 22 Wh·Kg−1 and excellent cycling performance (no capacity loss after 10 000 charge-discharge cycles).

Экспериментально-аналитические исследования токсичности продуктов горения, обнаружения и тушения пожаров в гермобарокамерах в средах, обогащенных кислородом и при повышенном давлении

Experimental and analytical studies were carried out related to the detection and extinguishing of fires, the toxicity of products in equipment with oxygen-enriched media and at elevated pressure. Toxicity of combustion products in the pressurized pressure chambers is due to the release of aerosol particles and gaseous products of thermal-oxidative destruction of materials, for which empirical dependences are presented over a wide temperature range allowing calculations to determine the integral relative yields of reaction products. Analysis of the experimental results shows that the increase in the mass yield of aerosol particles occurs more intensely than that of toxic gases, and a noticeable release of gases begins at a temperature of about 523 K, while the release of dispersed particles occurs already at a temperature of approximately 473 K. At the early stage of thermal destruction in the temperature range 473–623 K, the yield of aerosols is 5 times higher than the yield of gases by mass. When the temperature rises close to the ignition temperature, the combustion source can be detected using gaseous products, in particular CO and CO2. Justification for the methodology for assessing the main parameters of fire extinguishing in the pressurized chambers is given. The most important elements of the main components, elements and installation as a whole are: inertia, intensity of supply of fire extinguishing agent. Dependence obtained analytically, which was confirmed in experiments, between the extinguishing time and the intensity of the supply of fire extinguishing agent is presented, which considers the characteristics of the environmental parameters in the chamber and the thermophysical properties of the flame. Dependences were obtained related to the extinguishing time on the intensity of the supply of sprayed water, on the size of the sample, and on the oxygen content in the chamber atmosphere. Results of the experimental studies indicate that changes in oxygen concentration in the atmosphere have a more noticeable effect on extinguishing parameters than changes in gas pressure.

Research on Emotion Recognition Method of Cerebral Blood Oxygen Signal Based on CNN-Transformer Network.

In recent years, research on emotion recognition has become more and more popular, but there are few studies on emotion recognition based on cerebral blood oxygen signals. Since the electroencephalogram (EEG) is easily disturbed by eye movement and the portability is not high, this study uses a more comfortable and convenient functional near-infrared spectroscopy (fNIRS) system to record brain signals from participants while watching three different types of video clips. During the experiment, the changes in cerebral blood oxygen concentration in the 8 channels of the prefrontal cortex of the brain were collected and analyzed. We processed and divided the collected cerebral blood oxygen data, and used multiple classifiers to realize the identification of the three emotional states of joy, neutrality, and sadness. Since the classification accuracy of the convolutional neural network (CNN) in this research is not significantly superior to that of the XGBoost algorithm, this paper proposes a CNN-Transformer network based on the characteristics of time series data to improve the classification accuracy of ternary emotions. The network first uses convolution operations to extract channel features from multi-channel time series, then the features and the output information of the fully connected layer are input to the Transformer netork structure, and its multi-head attention mechanism is used to focus on different channel domain information, which has better spatiality. The experimental results show that the CNN-Transformer network can achieve 86.7% classification accuracy for ternary emotions, which is about 5% higher than the accuracy of CNN, and this provides some help for other research in the field of emotion recognition based on time series data such as fNIRS.

Research on the impact of rotor wear on the effectiveness of the aluminium refining process

Physical modelling is successfully used to understand mechanisms involved in the aluminium refining process by injecting inert gas into the liquid metal through rotors. Two types of industrial impellers, which are extremely different in construction, were tested in the research. The aim of the research was to determine the effectiveness of their operation depending on their degree of wear. This type of research has not been tested on water models so far. During the process, the parameters were changed, such as the gas flow rate from 13 to 19 L/min, the rotor speed from 325 to 400 rpm and the height of the rotor from the bottom of the refining reactor. Tests were carried out for new and worn rotors. Oxygen removal rate curves were prepared on the basis of tests determining changes in oxygen content in the model liquid as a function of time for changing rotor speed values. It was found that the efficiency of hydrogen removal from the model liquid was higher when worn impellers were used in the model. In order to verify results of model tests, a metallographic analysis of samples obtained in industrial conditions and using the analysed process parameters was carried out.

Structural and electrical properties of Bi3GaSb2O11 at high temperatures

We have investigated the crystal structure and electrical properties of Bi3GaSb2O11 at high temperatures. Neither phase transitions nor change in oxygen content were observed at 26–800 °C in air. The crystal structure was successfully refined using neutron diffraction data taken at 26–600 °C. The average thermal expansion coefficient between 26 and 600 °C was 10.4614(7) × 10‒6 °C‒1. There are three different (Ga/Sb)–O bonds of (Ga/Sb)–O3b, (Ga/Sb)–O2, and (Ga/Sb)–O3a. It was found that the thermal expansion coefficient of the (Ga/Sb)–O3b bond is lower than those of other bonds. At 916 °C the total DC electrical conductivity in N2 (1.4 × 10‒3 S cm‒1) was higher than that in air (7.1 × 10‒4 S cm‒1), due to electron conduction in N2. In air, oxide-ion conduction was suggested by electrical-conductivity and polarization measurements. Bond-valence-based-energy calculations suggested oxide-ion migration along the O–O edges and on O–O–O faces of (Ga/Sb)O6 octahedra.

Evaluating the Efficacy and Underlying Mechanisms of Acupuncture for Chronic Subjective Tinnitus Using Functional Near-Infrared Spectroscopy: Study Protocol for a Randomized Controlled Trial.

This study aims to evaluate the efficacy and safety of acupuncture for chronic subjective tinnitus and explore the central mechanism underlying acupuncture for chronic subjective tinnitus using functional near-infrared spectroscopy (fNIRS). We will randomly assign 60 tinnitus patients to either an acupuncture group or a waiting-list control group. The acupuncture group will undergo 12 treatment sessions over 4 weeks, whereas the waiting-list control group will receive no intervention concurrently. Clinical outcome measures include the Tinnitus Handicap Inventory (THI) score, tinnitus loudness assessed by 11-point NRS, average pure-tone threshold, and Hamilton Anxiety Scale (HAM-A) score. Neuroimaging outcomes assessed by fNIRS included blood oxygen concentration and resting-state functional connectivity (RSFC). All outcome measurements will be assessed at the baseline, after 4-week treatment, and at 3-month follow-ups. Our investigation will determine if significant differences exist between the two groups regarding THI, NRS, average pure-tone threshold, and HAM-A scores. Moreover, the analysis will reveal whether the acupuncture group demonstrates significant change in blood oxygen concentration and RSFC between specific brain regions compared to the waiting-list control group. With the novel technique of fNIRS, in addition to efficacy evaluation of acupuncture, this study's findings are anticipated to partly elucidate the neural mechanisms underlying acupuncture treatment for subjective tinnitus and offer an objective assessment method for its therapeutic impact, thereby contributing to filling the research gap. Clinicaltrials registry (identification code NCT05829278).

Evaluation of Usefulness of Yeast-Based Biological Phantom and Preliminary Study for Verification of Hypoxic Effect of Flash Radiotherapy

As a basic hypothesis for the effectiveness of flash radiation therapy, the effect of preserving normal tissue during flash radiation is due to the instantaneous chemical depletion of oxygen. A yeast-based biological phantom was created to verify the hypoxic effect of flash radiation therapy. A study to upgrade the previously developed X-Band LINAC to a flash irradiation mode is in progress, and a preceding study is conducted to evaluate the usefulness of a yeast-based biological phantom manufactured by analyzing the change in oxygen by irradiating a high dose in a general radiation therapy device. Freeze-dried yeast sample (Saccharomyces cerevisiae, S288C) is activated and sub-cultured. For mass production of yeast samples, yeast culture medium is prepared by adding yeast colonies to the ypd medium. This study was conducted to verify the hypoxic effect among the biological mechanisms that occur during flash radiation therapy at the basic stage, and the oxygen concentration change during general radiation irradiation was measured in real time using a DO (Dissolved oxygen) meter and fiber optic sensor designed to do that. To prevent scatter, which is a concern during flash irradiation, the fiber form was used, and precise experiments are possible as a non-invasive oxygen concentration measurement method. Based on 10MV of general radiation therapy device, high-dose radiation of 500-10,000 cGy is irradiated to measure real-time oxygen concentration change. As a result of irradiation with high-dose (500-10,000 cGy) radiation of general LINAC, it was confirmed that the oxygen concentration of the yeast culture medium decreased by 5.7-63.2%, and the usefulness of the biological phantom fabricated based on the yeast culture medium was evaluated. Prior to the analysis of oxygen concentration change in yeast cells during X-Band LINAC flash irradiation, a preliminary study was conducted at a high dose in a general LINAC to obtain a significant result of oxygen concentration change and confirm the usefulness of the yeast-based biological phantom. Prior research was conducted and verified as a general irradiation experiment using a yeast-based biological phantom manufactured based on a DO meter and a fiber optic oxygen sensor. After irradiation with high-dose radiation, the oxygen concentration of the yeast culture medium was measured 5 times, and it was confirmed that there was a change in oxygen concentration of 5.7-63.2%, verifying the usefulness and stability of the biological phantom. The usefulness of the yeast-based biological phantom for high doses was confirmed, and it is expected that the usefulness of the biological phantom for flash radiation can be verified by additionally measuring the change in oxygen concentration of the biological phantom according to the high dose rate in the future.

Calcium dynamics during the growth of Agaricus bisporus: implications for mushroom development and nutrition

BackgroundAgaricus bisporus (A. bisporus) is highly valued for its nutritional benefits and delicious taste, making it one of the most widely cultivated, highest yielding, and most consumed edible mushrooms worldwide. The yield and quality of A. bisporus were affected by its culture medium and environment. Among the culture base, the precise impact of calcium on A. bisporus cultivation and the dynamic changes in calcium concentration and chemical environment during the cultivation process remain unclear. This study aims to investigate the changes in calcium content and forms during the growth of A. bisporus and their implications for mushroom growth and nutrition.ResultsThrough the analysis of samples collected during the composting phase, mycelial development phase, and A. bisporus harvesting phase, the role of calcium in the growth process of button mushrooms is revealed. During the composting phase, the calcium content remains relatively stable, suggesting a consistent calcium source in the compost. The fermentation process shows a significant decrease in carbon content and an increase in oxygen content, indicating the degradation and oxidation of organic matter. In the mycelial development phase, both the cover soil and compost experience a decrease in calcium content, with a more pronounced reduction observed in the covering soil, indicating its primary role as an energy source for enzymatic activity and metabolic processes of the mycelium. During the A. bisporus harvesting phase, the changes in calcium, carbon, and oxygen content become less prominent, indicating a stable state of fruiting bodies growth that no longer requires a significant supply of organic matter.ConclusionsAnalysis of calcium forms reveals the presence of different calcium compounds, likely influenced by soil calcium sources, microbial activities, and mushroom metabolic byproducts. Calcium plays a crucial regulatory role in the growth and quality of A. bisporus. This study provides valuable insights into the significance of calcium in A. bisporus growth and offers theoretical guidance for optimizing mushroom production and quality improvement.Graphical