Rate Of Change In Concentration Research Articles

The decomposition rate and bleaching efficacy of in-office bleaching gels with different pHs: a randomized controlled trial.

To evaluate the decomposition rate of active hydrogen peroxide (HP) and bleaching efficacy during in-office bleaching using high-concentration HP gels with different pHs. A randomized, parallel, double-blind controlled trial was conducted with 40 volunteers randomized into four groups (pH 5.4; pH 7.0; pH 7.7, and pH 8.0). During the first session in-office bleaching, approximately 0.01g of the gel was collected and titrated with potassium permanganate to obtain the concentration of active HP and pH values were measured using an electrode. Bleaching efficacy was assessed using a spectrophotometer [∆Eab, ∆E00, and WID], Vita Classical and Vita Bleachedguide scales [∆SGU]. The decomposition rate of HP concentration and pH values change were calculated using ANOVA one-way. The bleaching efficacy was assessed using two-way repeated measures ANOVA. Tukey's test was applied as a post-hoc test (p < 0.05). All gels experienced decreasing HP concentration over time. pH 5.4 gel showed greatest reduction after 50min (p < 0.001). pH 8.0 and 7.7 gels remained stable; pH 5.4 remained acidic, while pH 7.0 turned acidic (p < 0.001). No significant difference in bleaching degree was observed among gels. They all showed a similar and clinically important color change after two clinical sessions, remained stable 1-month post-treatment (p > 0.05). All bleaching gels kept at least 70% of their HP content after 50min, suggesting that there is a surplus of HP. They provided similar whitening efficacy 1-month after bleaching. It is possible that lower HP concentrations may be equally effective in achieving desired results while reducing the potential for side effects. RBR-35q7s3v.

A high-throughput flowless microfluidic single and multi-solute concentration gradient generator: Design and parametric study.

Microfluidic concentration gradient generators (μ-CGGs) are critical in various biochemical assays, including cell migration, drug screening, and antimicrobial susceptibility testing. However, current μ-CGGs rely on integration with flow systems, limiting their scalability and widespread adoption owing to limited infrastructure and technical expertise. Hence, there is a need for flowless diffusional gradient generators capable of standalone operation, thereby improving throughput and usability. In this study, we model such a diffusional μ-CGG as an infinite source-sink system to capture two characteristic timescales: (i) gradient generation dictated by the diffusion timescale and (ii) stability determined by the rate of change in reservoir concentrations. Through finite-element simulations, we explored the influence of various geometric parameters such as the channel length, cross-sectional area, node and reservoir volumes, and the solute diffusivity on these timescales, along with experimental confirmation using fluorescent tracer diffusion. Our results show that while the gradient stability strongly depends on the reservoir volumes, diffusion length, and solute diffusion coefficient, they are independent of the node shape or the shape of the channel cross section. However, gradient profiles were found to be the strong functions of the diffusion length, solute diffusivity, and the geometric pattern of the microfluidic grid. Additionally, we showcased the versatility of the design by generating discrete gradient profiles and combinatorial gradients of two and three solutes, thus improving throughput in a wide range of on-chip biological assays. These findings underscore the potential of our microfluidic device as an easy-to-use, inexpensive, efficient, and high-throughput platform for various on-chip biological assays.

Development of a Compartment Model to Study the Pharmacokinetics of Medical THC after Oral Administration

The therapeutic potential of delta9-tetrahydrocannabinol (THC), a primary cannabinoid in the cannabis plant, has led to its development into oral medical products for treating various conditions. However, THC, being a psychoactive substance, can lead to addiction if taken in inappropriate amounts. Thus, studying the pharmacokinetics of THC is crucial for understanding how the drug behaves in the body after administration. This study aims to develop a multi-compartmental model to investigate the pharmacokinetics of medical THC and its metabolites after oral administration. Using the law of mass action, the model was converted into ordinary differential equations (ODEs) to describe the rate of concentration changes of THC and its metabolites in each compartment. The nonstandard finite difference (NSFD) method was then applied to construct numerical solution schemes, which were implemented in MATLAB along with estimated pharmacokinetic rate constants. The results demonstrate that the simulation curves depicting the plasma concentration–time profiles of THC and 11-hydroxy-THC (THC-OH) closely resemble actual data samples, indicating the model’s accuracy. Moreover, the model predicts the pharmacokinetics of THC and its metabolites in various tissues. Consequently, this model serves as a valuable tool for enhancing our understanding of the pharmacokinetics of THC and its metabolites, guiding dosage adjustments, and determining administration durations for oral medical THC.

Enhancing thermal performance of energy storage concrete through MPCM integration: An experimental study

Phase change materials melt and solidify at different temperature ranges called Phase change hysteresis. This phenomenon should be understood and evaluated in order to adequately design energy storage concretes for applications. Although many studies have analyzed the phase change process in pure - phase change materials such as paraffin. However, there is not enough information about the Phase change hysteresis of energy storage concrete. In order to realistically reproduce the working condition of concrete. This study explores phase change hysteresis in energy storage concrete slabs, focusing on the impact of microcapsule concentration and temperature change rate on thermal efficiency. Experiments were conducted to analyze the thermophysical properties, particularly observing the variations in specific heat capacity and phase transition temperatures. Results showed that increasing the microcapsule concentration enhances the specific heat capacity and latent heat of phase change, while faster temperature changes intensify hysteresis effects. Compared with the results of previous studies. Phase change hysteresis is more significant due to the pore and complex structure of energy storage concrete that impedes heat transfer. The experimental latent heat values were approximately 75 % of theoretical predictions, likely due to microcapsule damage and microstructural impacts on heat transfer. The study's findings are crucial for optimizing the thermal performance of energy storage concrete.

Assessment of exercise-induced stress via automated measurement of salivary cortisol concentrations and the testosterone-to-cortisol ratio: a preliminary study

In this study, our aim was to validate whether the automated measurement of salivary testosterone and cortisol concentrations and the testosterone-to-cortisol (T/C) ratio, considering their individual circadian rhythms can be used to assess the stress response of male athletes to different exercise intensities accurately and effectively. We measured the salivary testosterone and cortisol concentrations and their respective serum concentrations that were collected from 20 male long-distance runners via passive drooling in the morning and evening for two consecutive days involving different exercise intensities. An electrochemiluminescence immunoassay was performed to evaluate the salivary testosterone and cortisol concentrations. The results showed a positive correlation between the salivary testosterone and cortisol concentrations and their respective serum concentrations. The participants were divided into two groups: with and without interval training. The interval training group showed a significantly higher rate of change in the salivary cortisol concentration and a significantly lower rate of change in the T/C ratio in the evening interval training on day 1 than lower-intensity running on day 2. Our results indicated that the salivary cortisol concentrations and the T/C ratio could distinguish between exercises at different intensities, which may be beneficial for detecting differences in stress responses among athletes.

Experimental and Simulation Investigation of Total Dissolved Gas Prediction in Supersaturated Water Treatment: Focusing on Source Calibration and Combining with Bubble Coalescence

Supersaturation of total dissolved gas (TDG) is a common occurrence in high dams during the spill process, which can lead to fish bubble disease and threaten aquatic organisms. As a result, many scholars have taken a keen interest in this issue. Research into the gas-liquid mass transfer mechanism has improved the accuracy of TDG prediction models. This article investigates the factors affecting TDG dissipation through laboratory experiments. Especially, the mass transfer coefficient across the bubble interface based on the slip penetration model was calibrated, and the coaxial bubble coalescence added to the coefficient was studied. The results show that the aeration rate has the most significant impact, followed by water depth, and then the aeration aperture. The TDG dissipation rate increases with the parameter β, and the parameter of 0.35 shows the highest correlation with the experimental data. Furthermore, the concentration change rate after coalescence is lower than before, suggesting that aggregation negatively impacts mass transfer. This study improves TDG concentration prediction accuracy and proposes measures for mitigating supersaturation to avoid fish bubble disease.

Mercury concentrations decline with age in the fur of females of an insectivorous terrestrial mammal (Myotis lucifugus)

Methylmercury (MeHg) is a toxic form of mercury that bioaccumulates in organisms and biomagnifies through food webs. MeHg concentrations can be high in aquatic environments, and this puts high trophic-level predators who derive energy originating from aquatic environments at risk of toxic effects. Due to the potential for bioaccumulation of MeHg over an individual's life, the risk of MeHg toxicity may increase as animals age, and this risk may be especially high in species with relatively high metabolic rates. Total mercury (THg) concentrations were measured from the fur of adult female little brown bats (Myotis lucifugus) collected between 2012 and 2017 in Salmonier Nature Park, Newfoundland and Labrador. Using linear mixed-effects models, the effects of age, year, and day of capture on THg concentrations were evaluated and interpreted with AICc and multi-model inference. We expected that THg concentrations would increase with age, and that due to annual summer moulting, individuals captured earlier in the season would have lower THg concentrations than individuals captured later in the season. Contrary to expectations, THg concentrations decreased with age and date of capture did not explain any variation in concentration. Among individuals, there was a negative relationship between the initial THg concentration of an individual and the rate of change in THg concentrations with age. Using a regression analysis, we found evidence of a population-level decline in THg concentrations in fur over the 6-year study period. Overall, the results indicate that adult female bats eliminate enough MeHg from their tissues to affect a decrease in THg concentrations in their fur over time, and that young adults are potentially at the greatest risk of experiencing toxic effects from high MeHg concentrations; this could result in reduced reproductive output, and warrants further research.

Optimized fluegas denitrification control strategy to enhance SCR performance during load-cycling transient processes in coal-fired power plants

Selective catalytic reduction (SCR) is a common method for controlling NOx emission via NH3 injection. Coal-fired power plants are taking load-cycling processes with increasing frequency. During load-cycling processes, NOx emissions fluctuate and NH3 escape aggravates, which increases environmental pollution and degrades equipment safety. Therefore, the NH3 injection control strategy must be optimized to enhance denitrification performance during transient processes. In this study, an integrated NOx emission model of coal-fired units is developed and verified. The model includes the thermal system simulation, NOx production, and SCR system models. On the basis of the model, load-cycling processes are simulated under the traditional denitrification control strategy, wherein excessive NH3 injection and increased NOx and NH3 emissions are observed. The typical transient processes of the SCR system and boiler are simulated with various initial operating conditions and input parameter disturbances to explore the main factors affecting denitrification performance during load-cycling processes. The analysis of dynamic characteristics reveals that the inertia of NH3 storage is an important factor of unstable denitrification performance, and the temperature and fluegas flow rate influence the delay caused by this inertia, therefore the denitrification performance shows significant difference in various load-cycling processes. Consequently, an optimized NH3 control strategy is proposed. In this strategy, the change rate of NOx concentration is predicted according to the boiler load command, and the fluegas temperature and flow rate are also taken to adjust the additional NH3 injection. The simulation of typical load-cycling processes demonstrates that the optimized control strategy comprehensively enhances denitrification performance, where the NH3 injection, NOx emission and NH3 emission are all reduced. In particular, for the low- and medium-load range, the total amount of NH3 emission can be reduced by 5.69%, and the maximum values of NOx and NH3 emissions are reduced by 7.46% and 19.26%, respectively, which benefits both air pollutants emission reduction and equipment safety.

Retention effect and mode of capillary zone on the migration process of LNAPL pollutants based on experimental exploration

Two-dimensional sand tank experiments were designed to investigate the retention process of the capillary zone during the migration of light non-aqueous phase liquid (LNAPL) pollutants. The fine sand and silt media experiments simulated the LNAPL migration process given a shallow point source leakage scenario. The results indicate that the LNAPL was retained in the capillary zone. A retention factor, based on the ratio of the change in the vertical migration velocity of the LNAPL front with time, was proposed to quantitatively characterize the retention effect. The retention factor and time satisfied the function of σ=A×exp(−kt). And the retention factor increased gradually with time, indicating the enhanced retention effect of capillary zone on the vertical migration of LNAPL. The concentration change rate was then used to investigate the LANPL redistribution process, which had a relationship with time of νc=B×ln(t)+C. The capillary zone could be divided from top to bottom into a weak retention zone (B > 0, vc < 0), a strong retention zone (B < 0), and a barrier zone (B > 0, vc > 0). The retention effect of capillary zone on LNAPL migration gradually strengthened during the vertical migration of LNAPL. In addition, the coefficient B had a relationship with the environmental factors (i.e., EC, pH, and ORP) of B=a×sin(b×α×β×γ)c and the fitting coefficient R2 of the function was above 0.913 for both media, indicating a strong correlation between the LNAPL redistribution process and the key environmental factors.

A Total Transmitted Light Intensity Method for Detecting Concentration of Glucose Aqueous Solution Directly Irradiated by Near Infrared LED

Glucose plays an important role in biological fermentation and biosensing. Therefore, it is very important to detect the concentration of glucose aqueous solution quickly and accurately. A novel method for detecting the concentration of glucose solution is introduced in this article. Based on the spectral characteristics of the near-infrared light-emitting diode (NIR LED), the total transmitted light intensity (TTLI)-concentration model of glucose solution directly irradiated by NIR LED was established to detect the concentration of glucose solution. In this model, firstly, the TTLI of glucose solution and TTLI of deionized water were defined. Secondly, the definition formula of the change ratio of TTLI was provided. Finally, the linear relationship between the change ratio of TTLI and the concentration of glucose solution was derived. In order to verify the effectiveness of the TTLI method, NIR LED Glucose Solution Concentration Detection System (NIR LED-GSCDS) was designed. In this system, an alternating measurement method is designed to reduce the influence of the radiation fluctuation of the NIR LED light source on the accuracy of detection results, and the thermostatic circulation subsystem is designed to reduce the influence of the change of solution temperature on the infrared light absorption rate of glucose solution. The experimental results show that the linear correlation coefficient between the change rate of TTLI and glucose solution concentration is 0.998 and the relative uncertainty is 8.2% in the concentration range of 1000–5000 mg/dL. Therefore, the TTLI method can determine the concentration of glucose solution under the direct irradiation of the NIR LED light source without a complex spectroscopic system.

Longitudinal Changes in Blood Biomarkers of Clinical Alzheimer Disease in a Biracial Population Sample.

Recent studies suggest the utility of blood biomarkers in detecting changes in neurodegenerative disorders. The objective of our research was to test the hypothesis that the longitudinal changes in total tau (t-tau), neurofilament light chain (Nf-L), and glial fibrillary acidic protein (GFAP) are associated with structural MRI and the development of clinical Alzheimer disease (AD) and cognitive decline. Data came from a population-based sample with serum concentrations of t-tau, Nf-L, and GFAP and cognitive characteristics measured over 17 years. The inclusion criteria for this investigation were based on participants with blood samples, cognitive function testing, and clinical diagnosis for AD. The longitudinal changes in the serum biomarkers were examined using linear mixed models for log10-transformed concentrations. In 1,327 participants (60% Black participants and 60% women, the concentration of t-tau increased annually by 4.8% (95% CI = 4.0-5.6) and Nf-L by 5.9% (95% CI = 5.4-6.4). The longitudinal change in GFAP was higher among Black participants than among White participants (4.4% vs 3.5% per year, p = 0.028). Baseline MRI characteristics were associated with the longitudinal changes in serum biomarkers of clinical AD. Specifically, a higher baseline third ventricular volume was associated with a higher rate of increase in the concentration of t-tau, and white matter hyperintensities predicted a higher rate of increase in Nf-L. The rate of change in concentrations of t-tau, Nf-L, and GFAP was significantly higher among those who developed clinical AD than in those with no cognitive impairment. For each standard deviation unit decline in global cognition, longitudinal change in t-tau increased by 81% (95% CI = 76-86), Nf-L by 113% (95% CI = 105-120), and GFAP by 66% (95% CI = 62-70). Blood biomarkers showed significant longitudinal changes corresponding to cognitive decline, clinical AD, and structural MRI characteristics. Our findings show that longitudinal changes in serum biomarkers were associated with several cognitive endophenotypes. The study found Class II evidence that longitudinal changes in serum t-tau, Nf-L, and GFAP were associated with cognitive decline and the development of clinical AD in people older than 65 years.

Comparing the Rise in Glucose Concentration in Blood, Aqueous and Interstitial Fluid During a Glucose Tolerance Test.

The purpose of the study was to determine if aqueous glucose levels rise in a comparable time frame to interstitial fluid and could therefore be suitable for a continuous glucose monitoring (CGM) site. An intravenous glucose tolerance test was performed on five New Zealand white rabbits. Aqueous humor from the posterior and anterior chamber of the eye and venous blood were sampled for glucose concentration measurement. Glucose concentrations in the interstitial fluids were monitored using a CGM system. A compartment model was created to map the glucose response curves in each compartment. The delay in rising glucose concentrations between blood and interstitial fluid and aqueous humor in the posterior chamber and anterior chamber of the eye were analyzed. The results showed a statistically similar time lag and rate of change in glucose concentrations between blood and interstitial fluids or aqueous humor in either the posterior or anterior chamber. The results of this study add further support to the aqueous humor being used as an alternative CGM site. The study provides the basis for developing an intraocular continuous glucose sensor that can overcome limitations of current CGM systems.

Analysis of apoB Concentrations Across Early Adulthood and Predictors for Rates of Change Using CARDIA Study Data

The cumulative exposure to apolipoprotein B (apoB)-containing lipoproteins in the blood during early adult life is a central determinant of atherosclerotic cardiovascular disease risk. To date, the patterns and rates of change in apoB through early adult life have not been described. Here, we used NMR to measure apoB concentrations in up to 3055 Coronary Artery Risk Development in Young Adults (CARDIA) Study participants who attended the years 2 (Y2), 7 (Y7), 15 (Y15), 20 (Y20), and 30 (Y30) exams. We examined individual-level spaghetti plots of apoB change, and we calculated average annualized rate of apoB concentration change during follow-up. We used multivariable linear regression models to assess the associations between CARDIA participant characteristics and annualized rates of apoB change. Male sex, higher measures of adiposity, lower HDL-C, lower Healthy Eating Index, and higher blood pressures were observed more commonly in individuals with higher apoB level at Y2 and Y20. Inter- and intra-individual variation in apoB concentration over time was substantial—while the mean (SD) rate of change was 0.52 (1.0) mg/dl/year, the range of annualized rates of change was −6.26 to +9.21 mg/dl/year. At baseline, lower first apoB measurement, female sex, White race, lower BMI, and current tobacco use were associated with apoB increase. We conclude that the significant variance in apoB level over time and the modest association between baseline measures and rates of apoB change suggest that the ability to predict an individual’s future apoB serum concentrations, and thus their cumulative apoB exposure, after a one-time assessment in young adulthood is low.

Экспериментально-аналитические исследования формирования пожаровзрывоопасных паровоздушных облаков в атмосфере при утечках и проливах жидкого водорода

Experimental and numerical studies of the process of formation of fire-explosive steam-air clouds in the atmosphere during leaks and spills of liquid hydrogen were carried out. Within their framework, the tasks were performed to determine the size and lifetime of a hydrogen-air cloud with a hazardous concentration of hydrogen from the point of view of explosion and fire hazard (including at the boundary of a visible cloud), and the relationship between the temperature and concentration of combustible gas in a gas-air cloud; studying the effect of cloud temperature on its parameters, the role of atmosphere involvement in the convective hydrogen jet; establishing the influence of moisture content in the atmospheric cloud and the mobility of the environment (wind exposure) on the dynamics of changes in the level of its fire and explosion hazard. It is shown that the humidity of the environment affects the concentration of hydrogen at the boundary of the visible cloud, and, consequently, its fire and explosion hazard. The assessment of the influence of humidity on the parameters of the studied turbulent convective jet indicates that the rate of change in the mass concentration of hydrogen on the axis of the low-temperature jet from the height of ascent depends on the humidity of the medium. The higher the humidity, the sharper the decrease in the mass concentration of hydrogen along the height of the convective jet becomes. In accordance with the calculations, the time for dissipation of a cloud to a fireproof hydrogen concentration in the presence of moisture condensate is reduced by 30 %, and the dissipation time to an explosive concentration of hydrogen is reduced by about 20 %. The coefficient of air involvement α in convective jets of hydrogen-air mixtures with positive buoyancy is 0.12 considering the real enthalpy and absolute humidity of the surrounding air of 15 g/m3 (90 % humidity at 20 °C). This coefficient can be used in the calculations of turbulent convective jets formed during stationary hydrogen evaporation. Wind at low speeds leads to an increase in the maximum transverse dimensions of the cloud, regardless of the concentration in the hydrogen jet, and at high speeds, to their decrease. For emergency hydrogen spills, the most dangerous case when a hydrogen-air cloud of large volumes is formed in the atmosphere, is the case with zero humidity and no wind (in a wide range of values of the initial mass flow of hydrogen: 0.1–100 kg/s).

Dramatic changes in aerosol composition during the 2016–2020 heating seasons in Beijing–Tianjin–Hebei region and its surrounding areas: The role of primary pollutants and secondary aerosol formation

With the implementation of a series of air pollution mitigation strategies during the past decade, great air quality improvements have been observed in the BTH region. Despite of significant decreases in gaseous pollutants, such as SO2 and NO2, the enhancement of secondary aerosol formation was observed. NO3− has surpassed SO42− and OM to become the dominant PM2.5 component. We find that the reduction of POC mainly dominated the decreasing trend of OC. As for secondary inorganic components, the key processes or factors controlling the spatial-temporal variation characteristics were different. The areas with large SO42− concentrations corresponded well to those with high SO2 concentrations, while the synchronized NO3− better followed spatial patterns in O3 than NO2. From 2016 to 2020, the response of SO42− to SO2 was close to a linear function, while the reaction of NO3− to the decrease of NO2 displayed nonlinear behavior. Such different relationships indicated that SO42− was predominantly controlled by SO2, while NO3− was not only related to NO2 but also determined by the secondary conversion process. The ratios of SO42−, NO3−, NH4+, and OC to EC between 2016 and 2020 were generally higher than 1 in typical BTH cities, and the ratio of NO3− to EC was exceptionally high, with a range reaching up to 200 %. Besides, this ratio coincided well with the enhancement of Ox, indicating the potential role of Ox to secondary NO3− formation. The diurnal cycle of NO3−, O3, and NO2 concentration change rate indicated that the relative increase of O3 during nighttime may offset the effectiveness of NOX emission reduction. This study provided observational evidence of enhanced secondary NO3− formation with the rising trend of atmospheric oxidation and emphasized the importance of nighttime chemistry for NO3− formation in the BTH region.

Differences in stress response between two altitudes assessed by salivary cortisol levels within circadian rhythms in long-distance runners

There are conflicting reports regarding the efficacy of cortisol as a stress marker in altitude training due to the influence of the circadian rhythm. This study aimed to verify whether the automated measurement of salivary cortisol concentration via sequential sampling could detect the differences in exercise stress between two altitudes. We enrolled 12 elite female long-distance runners living near sea level. For the first higher-altitude camp, the runners lived at 1800 m and trained at 1700 m for 7 days. For the second lower-altitude camp, they lived at 1550 m and trained at 1300 m for 7 days. Their saliva was sequentially collected on the last 2 days during each camp which involved different intensity exercises in the morning and afternoon. The salivary cortisol concentrations were measured using electrochemiluminescence immunoassay. Before dinner, the basal salivary cortisol concentrations were significantly higher in the higher-altitude camp. The rate of change in the salivary cortisol concentration during the morning exercise was significantly higher in the higher-altitude camp than in lower-altitude camp (p = 0.028) despite the same exercise programs and intensities. Salivary cortisol level measurements during the athletes' circadian rhythms could detect the differences in acclimatization and exercise stress between two altitudes.

Smart control of HVAC based on measurements of indoor radon concentration

Sufficient ventilation is important for creating a healthy indoor environment in both households and larger buildings (schools, offices, shops, warehouses). As the cost of heating and ventilation in large buildings is very large, modern ventilation systems apply smart control for optimizing the energy consumption. The control is typically based on temperature and/or CO2 levels, whereas other pollutants such as particulate microparticles and radon are not accounted for. Exposure to indoor radon is the second most important reason for lung cancer, with more than 200 000 casesestimated worldwide every year. The indoor radon concentration depends on many factors, from local geological conditions and weather, to building materials and natural and mechanical ventilation. Together with the Norwegian company OBEO AS, NORCE has completed a study of the indoor radon concentration at a Norwegian primary school prone to high radon levels. The study includes continuous measurements of radon, CO2 and temperature for multiple rooms for different use as well as data for the ventilation system. The aim for the project was to build knowledge for a larger research project, where the goal is to develop a control algorithm for HVAC systems which also takes radon levels into account. An important challenge is to make accurate sensors for measuring radon continuously at an affordable price for implementation in complex buildings. Generally, sensors that can measure at high frequency with good accuracy is very expensive. Thus, developing algorithms and mathematical models to treat the data from low-cost sensors can be an adequate tool for large systems/buildings. One must also account for the positioning of the sensor. For instance, it is known that the radon concentration is better distributed in a room with mechanical ventilation than in a room without, making the position of the sensor important for better interpretation of measurement data. In the pre-project we have studied how the radon levels show large variations that are related to the ventilation operation and daily/weekly variations. The large variations show the need for a high sampling rate (minutes to hours) to capture the peaks in the concentration. We have also studied the rate of change in radon concentrations over time and have amongst discovered a noticeable delay from the start of ventilation until radon is effectively removed from the air. The rate of change is an important parameter for planning ahead and securing fresh air during the full period of presence whilst optimizing the energy cost.

Quantitative Assessment of Temporal Changes in Subaqueous Hydrothermal Activity in Active Crater Lakes During Unrest Based on a Time-Series of Lake Water Chemistry

Regular sampling of lake water has been performed at many volcanoes to assess the state of volcanic activity. However, it is not clear whether the absolute concentrations or, instead, rate of changes in concentrations are more suitable for such assessments. In this study, we show that temporal changes in concentrations of an element in lake water are described by a simple differential equation, assuming changes in lake volume and chemical processes are negligible. The time constants (63% response time for changes in the chemical concentration in lake water) have a wide range varying between 20 and 1,000 days for the studied volcanoes in Japan, meaning it takes a long time to assess volcanic activity based on the absolute concentration of an element. In order to assess the volcanic activity in a shorter time period, based on a time-series of lake element concentration data, we developed a numerical model to calculate temporal changes in the steady-state concentration, which is proportional to the elemental concentrations of the bulk hydrothermal fluid injected from subaqueous fumaroles and hot springs. We applied our method to Yugama crater lake at Kusatsu–Shirane volcano, Japan, and quantitatively evaluated temporal changes in the hydrothermal input from 1964 to 2020. As a result, we detected changes in the Cl concentrations of the bulk hydrothermal input that were associated with unrest including the phreatic eruption in 1976 and earthquake swarms in 1989–1992 and 2014–2020. The future concentration in the lake water can be predicted from the most recent steady-state concentrations. Comparing the predicted concentration curve with the concentration obtained from lake water samples, it is possible to quickly assess whether the concentration of the bulk hydrothermal input has increased/decreased or remained constant.

Measured analysis of indoor pollutant concentration and air change rate in winter in the postgraduate dormitory of a university in Shenyang

In this paper, taking 17 graduate male dormitories of a university in Shenyang as the research object, the relationship between the characteristics of internal personnel and pollutants, the relationship between pollutant concentration and air change rate in the winter dormitory is analyzed by means of questionnaire survey and measurement. Through test analysis, it was found that the number of students in the dormitory whose actual weight exceeded 10% of the normal weight was greater than or equal to 2 people, which would cause the indoor CO2 concentration to be significantly higher than that of the normal weight dormitory, and the smoking of students in the dormitory would cause an increase in indoor PM2.5 concentration; For indoor CO2 concentrations of more than 2000ppm in dormitories that are sealed all night, reasonable window ventilation is required to effectively reduce the concentration of gas pollutants; According to the questionnaire survey, it is known that students do not use doors and windows for ventilation, so that indoor air does not circulate, causing students to have drowsiness, lack of concentration, chest tightness and other symptoms. The results of the study provide a reference for improving air quality and ventilation strategies in university dormitories.

Increased Plasma Soluble PD-1 Concentration Correlates with Disease Progression in Patients with Cancer Treated with Anti-PD-1 Antibodies.

Immune checkpoint inhibitors (ICIs) confer remarkable therapeutic benefits to patients with various cancers. However, many patients are non-responders or develop resistance following an initial response to ICIs. There are no reliable biomarkers to predict the therapeutic effect of ICIs. Therefore, this study investigated the clinical implications of plasma levels of soluble anti-programmed death-1 (sPD-1) in patients with cancer treated with ICIs. In total, 22 patients (13 with non-small-cell lung carcinoma, 8 with gastric cancer, and 1 with bladder cancer) were evaluated for sPD-1 concentration using enzyme-linked immunosorbent assays for diagnostic and anti-PD-1 antibody analyses. sPD-1 levels were low before the administration of anti-PD-1 antibodies. After two and four cycles of anti-PD-1 antibody therapy, sPD-1 levels significantly increased compared with pretreatment levels (p = 0.0348 vs. 0.0232). We observed an increased rate of change in plasma sPD-1 concentrations after two and four cycles of anti-PD-1 antibody therapy that significantly correlated with tumor size progression (p = 0.024). sPD-1 may be involved in resistance to anti-PD-1 antibody therapy, suggesting that changes in sPD-1 levels can identify primary ICI non-responders early in treatment. Detailed analysis of each cancer type revealed the potential of sPD-1 as a predictive biomarker of response to ICI treatment in patients with cancer.