Concentration Measurements Research Articles

Measurement of Radon Gas Concentration in Sources of Drinking Water in Makurdi, Benue State, Nigeria Using Radon Detector (RAD-7)

Study’s Excerpt Radon gas contamination across diverse drinking water sources within Makurdi, Nigeria, was investigated. The RAD-7 detector was used, and the results revealed elevated radon levels exceeding WHO limits in some specific locations. There is a need for targeted risk mitigation strategies and continuous monitoring of Radon gas contamination in the area. Full Abstract Concern over radon gas's potential health risks when used or ingested in homes is growing, as is the issue with its presence in sources of drinking water. In this study, water samples were collected from various locations in Makurdi, Benue State, Nigeria, and the amount of radon gas present was measured using the Radon Detector (RAD-7). The study used a methodical sampling strategy to gather water samples from wells, boreholes, and surface water bodies throughout various Makurdi locations. The gathered water samples were examined using the RAD-7 detector, a trustworthy and sensitive device for measuring radon gas. The radon levels ranged from trace levels (20.0 ) to higher quantities (122.0 ), raising worries about potential health implications for nearby people reliant on these water sources. Thirty (30) samples of water were gathered for this investigation. The samples' radon content ranged from 10.3 to 122.0 Bq L-1, which is within the World Health Organization's (WHO) allowable limit and other regulatory bodies (100 Bq L-1) except in the sample collected from Court 5 and Logo1, which was higher than the set limit. The results of the analysis demonstrated that there were large variations within the range of 0.61 0.39-11.80 1.85 and a mean of 57.36 in the amounts of radon gas in the water samples obtained from the different sources. More research and monitoring are advised to gain a complete understanding of radon distribution and to develop workable radon risk reduction plans for water sources.

Partial molar and microstructural properties of binary propane + o-toluidine system near the critical point of pure solvent based on the VLE measurements and modeling with CP-PC-SAFT and mg-SAFT equation of states

The isothermal VLE properties (PTxy relationship) of a binary supercritical (SC) C3H8 + o-toluidine mixture was measured by means of static-analytic method with fluid phase sampling at equilibrium conditions. The measurements were made at three temperatures of (393.15, 433.15, and 473.15) K and pressures up to 10.41 MPa. An experimental VLE apparatus, a high-temperature and high-pressure optical cell, has been used to measure the phase equilibrium properties (PTxy) of the binary SC C3H8 + o-toluidine mixture. The combined expanded absolute and relative uncertainties of the temperature, pressure, and the phase concentration measurements at 0.95 confidence level with a coverage factor of k = 2 is estimated at 0.15 K, 0.5 %, 4.2 % (for x) and 4.8 % (for y), respectively. The critical curve data, TC−x,PC-x, and PC− TC projections, have been derived based on the measured VLE data. The measured VLE and the derived critical curve data were used to estimate the theoretically important and physical meaning of Krichevskii parameter, ∂P∂xTCVC∞. Thermodynamic (partial molar properties, V¯2∞,H¯2∞,C¯P2∞, and distribution equilibrium constant KD), and microstructural (cluster’s size, Nexc∞) properties of infinite-dilute C3H8 + o-toluidine mixture near the critical point of pure solvent (C3H8) were calculated based on the derived Krichevskii parameter and pure solvent (SC C3H8) properties. CP-PC-SAFT and mg-SAFT equation of state (EoS), with zero interaction parameter, k12 = 0, for both models (pure prediction models, no adjustable parameters) were successfully applied to the present PTxy phase equilibria for the SC C3H8 + o-toluidine mixture. The present measured VLE data for C3H8 + o-toluidine system along with the reported pure compound properties of pure propane and o-toluidine have been used to examine the predictive capabilities of the theoretically based CP-PC-SAFT and mg-SAFT models of EoS. It was demonstrated that mg-SAFT is superior in predicting VLE of the C3H8 + o-toluidine system with k12 = 0.

Synergistic combinations of novel polymyxins and rifampicin with improved eradication of colistin-resistant Pseudomonas aeruginosa biofilms

BackgroundIncreased prevalence of antimicrobial resistance coupled with a lack of new antibiotics against Gram-negative bacteria emphasize the imperative for novel therapeutic strategies. Colistin-resistant Pseudomonas aeruginosa constitutes a challenge, where conventional treatment options lack efficacy, in particular for biofilm-associated infections. Previously, synergy of colistin with other antibiotics was explored as an avenue for the treatment of colistin-resistant infections, and recently we reported our efforts towards colistin analogs capable of combating planktonic colistin-resistant strains. AimsThe aim of the present study was to investigate whether analogs of polymyxin B with improved potency in wild-type and moderate resistant Gram-negative pathogens would retain similarly increased activity in highly colistin-resistant clinical P. aeruginosa isolates (in planktonic and biofilm growth) when applied alone and in combination with rifampicin. Materials and methodsIn this in vitro study, we tested three analogs of polymyxin B prepared by solid-phase peptide synthesis. Antimicrobial susceptibility testing was performed by measurement of minimum inhibitory concentrations via the broth microdilution method. Interactions between two antimicrobials was quantified in a checkerboard broth microdilution assay by calculating the fractional inhibitory concentration index for each combination. For testing of antibiofilm activity a previously described model with alginate beads encapsulating a biofilm culture was applied. The minimum biofilm eradication concentrations (MBECs) were evaluated, and the fractional biofilm eradication concentration indices were calculated. Three recently identified colistin analogs (CEP932, CEP936 and CEP938) were tested against three isogenic pairs of colistin-susceptible and colistin-resistant P. aeruginosa clinical isolates as well as the reference strain PAO1. ResultsFor bacteria in planktonic growth CEP938 retained almost full potency in all three resistant isolates, while exhibiting similar activity as colistin in susceptible isolates. Against biofilms CEP938 was slightly more potent against PAO1 as compared to colistin, while also retaining activity against a biofilm of the colistin-resistant strain 41,782/98. Next, synergy between CEP938 and the antibiotic rifampicin was explored. Interestingly, CEP938 did not exhibit synergy with rifampicin in planktonic cultures. Importantly, for colistin-resistant biofilms the CEP938-rifampicin combination demonstrated activity superior to that found for the colistin-rifampicin combination. ConclusionsThe present study showed in vitro efficacy of CEP938 against both colistin-susceptible and colistin-resistant P. aeruginosa biofilms as well as an ability of CEP938 to synergize with rifampicin in biofilm eradication.

Pharmacokinetics of a Natural Self-emulsifying Reversible Hybrid-Hydrogel (N'SERH) Formulation of Full-Spectrum Boswellia serrata Oleo-Gum Resin Extract: Randomised Double-Blinded Placebo-Controlled Crossover Study.

The oleo-gum-resin of Boswellia serrata, an Ayurvedic herb for the treatment of chronic inflammatory diseases, contains both volatile (terpenes) and nonvolatile (boswellic acids) molecules as responsible for its bioactivity. The present randomized, double-blinded, placebo-controlled, crossover study evaluated the human pharmacokinetics of a 'natural' hybrid-hydrogel formulation of a unique full-spectrum boswellia extract (BFQ-20) (standardized for both volatile and nonvolatile bioactives) in comparison with unformulated extract (U-BE), for the first time. Mass spectrometry coupled with LC (UPLC-MS/MS) and gas chromatography (GC-MS/MS) measurements of the plasma concentration of boswellic acids and α-thujene at different post-administration time points followed by a single dose (400 mg) of U-BE and BFQ-20, to healthy volunteers (n = 16), offered 4-fold enhancement in the overall bioavailability of boswellic acids from BFQ-20, [area under the curve (AUC) (BFQ-20) = 9484.17 ± 767.82 ng * h/mL vs. AUC (U-BE) = 2365.87 ± 346.89 ng * h/mL], with the absorption maximum (Tmax) at 6.3 h post-administration and elimination half-life (T1/2) of 15.5 h (p < 0.001). While plasma α-thujene was not detectable upon U-BE administration, BFQ-20 provided significant absorption, [AUC (BFQ-20): 298.60 ± 35.48 ng * h/mL; Cmax: 68.80 ± 18.60 ng/mL; Tmax: 4.12 ± 0.38 h; T1/2: 16.24 ± 1.12 h]. Further investigation of the anti-inflammatory effect revealed 70.5% inhibition of paw edema in rats compared to 38.0% for U-BE. In summary, the natural self-emulsifying reversible hybrid-hydrogel (N'SERH) formulation of boswellia extract using fenugreek mucilage (FenuMat®) significantly increased the solubility (58-fold), stability, and bioavailability of both the volatile and non-volatile bioactives which in turn improved the anti-inflammatory efficacy of Boswellia extract.

Continuous Biosensor Based on Particle Motion: How Does the Concentration Measurement Precision Depend on Time Scale?

Continuous biosensors measure concentration-time profiles of biomolecular substances in order to allow for comparisons of measurement data over long periods of time. To make meaningful comparisons of time-dependent data, it is essential to understand how measurement imprecision depends on the time interval between two evaluation points, as the applicable imprecision determines the significance of measured concentration differences. Here, we define a set of measurement imprecisions that relate to different sources of variation and different time scales, ranging from minutes to weeks, and study these using statistical analyses of measurement data. The methodology is exemplified for Biosensing by Particle Motion (BPM), a continuous, affinity-based sensing technology with single-particle and single-molecule resolution. The studied BPM sensor measures specific small molecules (glycoalkaloids) in an industrial food matrix (potato fruit juice). Measurements were performed over several months at two different locations, on nearly 50 sensor cartridges with in total more than 1000 fluid injections. Statistical analyses of the measured signals and concentrations show that the relative residuals are normally distributed, allowing extraction and comparisons of the proposed imprecision parameters. The results indicate that sensor noise is the most important source of variation followed by sample pretreatment. Variations caused by fluidic transport, changes of the sensor during use (drift), and variations due to different sensor cartridges and cartridge replacements appear to be small. The imprecision due to sensor noise is recorded over few-minute time scales and is attributed to stochastic fluctuations of the single-molecule measurement principle, false-positive signals in the signal processing, and nonspecific interactions. The developed methodology elucidates both time-dependent and time-independent factors in the measurement imprecision, providing essential knowledge for interpreting concentration-time profiles as well as for further development of continuous biosensing technologies.

Novel single-cell measurements suggest irreversibly sickled cells are neither dense nor dehydrated

In sickle cell anemia, deoxygenation causes erythrocytes to distort, while reoxygenation permits them to recover a normal biconcave disk shape. Irreversibly sickled cells (ISCs) remain distorted when reoxygenated and have been thought to have among the highest intracellular hemoglobin concentrations of the sickle red cell population and therefore the greatest vulnerability to vasoocclusion. Using a new optical method, which we describe, we have made precise measurements of the intracellular hemoglobin concentration, and intracellular O2 saturation, of ISCs, as well as oxygenated sickle cells with a normal biconcave disc shape, and cells with shapes distorted by the sickle fibers they contain. This method also provides good estimates of cell volumes, and hemoglobin per red cell. The concentration distribution of the ISCs is found to be similar to normal, discoid cells. Average ISC volumes exceed their discoid counterparts, with a much broader distribution, arguing against dehydration as their origin. The concentration distribution of the polymer-laden sickled cells is significantly higher in mean value, and their volume distributions indicate some dehydration. Previous assumptions about ISCs may have thus been colored by the presence of sickle cells that did contain polymer, and true ISCs may be much more benign than once thought, which underscores the importance of accurate measurement on individual cells. This method could be used to follow changes in individual cell properties under various specific perturbations, and where characterization by flow cytometry is infeasible.

Identification of factors associated with vancomycin-induced acute kidney injury: A retrospective analysis using the Common Data Model.

Previous findings on predictors of vancomycin-induced acute kidney injury (AKI) are inconsistent. We aimed to identify the predictors of vancomycin-induced AKI using the Observational Medical Outcome Partnership Common Data Model. We analyzed data from patients treated with vancomycin between January 1, 2012, and May 31, 2022, who were positive for Staphylococcus aureus and had undergone oxacillin susceptibility tests. After excluding patients without data for vancomycin or baseline serum creatinine levels, 116 patients were included in the final dataset. Data up to the third measured vancomycin concentration were collected for each patient. Logistic regression models were used to estimate the odds ratio and 95% confidence interval for each variable associated with vancomycin-induced AKI. High baseline serum creatinine levels, intensive care unit admission, and concurrent renal disorders were significantly associated with vancomycin-induced AKI. Although high trough levels or area under the curve values were not significantly associated with vancomycin-induced AKI, both were significantly higher in patients with AKI than in those without AKI at the second vancomycin concentration measurement. The proportion with trough levels >20mg/L was higher in patients with AKI than in those without AKI at the third measurement. Our findings revealed that underlying renal disease and intensive care unit admission are more significantly associated with vancomycin-induced AKI than vancomycin pharmacokinetic parameters or dosage, likely due to vancomycin concentration-based dosage adjustment in clinical settings. Our findings may help develop strategies for reducing the incidence of vancomycin-induced AKI; however, further prospective studies are essential.

Measurement of ethanol concentration for monitoring the solvent exchange during the alcogel preparation

A crucial and time-consuming stage in aerogel production is the solvent exchange process for alcogel formation. This process involves multiple steps, exposing the hydrogel to ethanol solutions with increasing concentration until the equilibrium in each step. Currently, the determination of contact time between phases (hydrogel and liquid solution) is either arbitrary or based on prior studies. However, considering the unique physicochemical characteristics of each system, as well as the solid-liquid interactions and the liquid diffusion within the matrix, the required time may vary. Monitoring this step can lead to a reduction in the time needed for alcogel production and the optimization of the entire process. The refractive index serves as a tool to assess ethanol concentration in the liquid solution over time, providing immediate information about the status of the solvent exchange. Alongside, differential scanning calorimetry can be employed to evaluate ethanol content in the alcogel (solid phase), confirming the attainment of equilibrium between phases.•This research introduces a technique for monitoring solvent exchange.•Refractive index measurement of the liquid solvent offers immediate concentration information into the status of the solvent exchange.•Differential scanning calorimetry is applicable for measuring the ethanol content within the alcogel and validating refractive index findings.

Virological History Predicts Non-sustained Viral Suppression With Long-Acting Cabotegravir and Rilpivirine Therapy, Independent of Pharmacokinetic Parameters

Abstract Background This study aimed to investigate factors contributing to non-sustained viral suppression, including intermittent viremia and persistent low-level viremia, during cabotegravir (CAB) plus rilpivirine (RPV) long-acting (LA) injectable therapy, with a focus on pharmacokinetics (PK). Methods A prospective cohort study was conducted on people with human immunodeficiency virus (HIV, PWH) transitioning from stable oral antiretroviral therapy (ART) to bimonthly CAB + RPV LA. Standardized follow-up included close monitoring through blood sampling for plasma human immunodeficiency virus type 1 (HIV-1) viral load (VL) and multiple plasma drug concentrations measurements to analyze the connection between PK parameters and virologic outcomes. Results Among 173 patients with a median (interquartile range [IQR]) follow-up of 11.1(7.1–13.2) months and 789 pre-dose measurements, 38.7% experienced VL ≥ 20 copies/mL, and 16.2% had levels ≥50 copies/mL. Intermittent viremia occurred in 34.7% of patients, and persistent low-level viremia in 4%. Virological failure developed in 2 cases. Predictors of non-sustained viral suppression included VL at HIV diagnosis (adjusted hazard ratio [AHR]: 1.49 per log10 VL, 95% confidence interval [CI]: 1.04–2.12, P = .027), detectable viremia on oral ART (AHR: 2.45, 95% CI: 1.29–4.65, P = .006), and the level of viral suppression at transition (AHR: 0.38, 95% CI: .19–.75, P = .004). We found a significant association between low trough concentrations of CAB and RPV and episodes of detectable viremia exceeding 50 copies/mL. However, none of the assessed PK covariates predicted non-sustained viral suppression in multivariable models. Conclusions Non-sustained viral suppression in PWH transitioning from stable oral ART to CAB + RPV LA was linked to preexisting factors before transition. Higher VL pre-ART and incomplete suppression on oral therapy increased the risk, independent of PK parameters.

Quantitative Analysis of the Li-Ion Solvation Structure in Li-Ion Battery Electrolytes Using ATR-FTIR Spectroscopy.

Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy is widely used to study condensed materials due to its convenient sample preparation and ability to avoid absorption saturation. Recently, it has been applied to in situ and in operando observations of chemical reactions within electrochemical devices, such as lithium-ion batteries. However, because ATR-FTIR spectroscopy relies on frequency-dependent attenuated reflectance, quantitative concentration measurements of chemical species using the Beer-Lambert law are challenging. Despite the availability of several correction methods, discrepancies remain in the solvation structures around Li+ ions when comparing transmission-type FTIR and ATR-FTIR spectroscopy results, which complicate the determination of solvation and desolvation energies. In this study, we investigate ATR-FTIR correction algorithms, elucidate the reasons for the discrepancies between ATR-FTIR and transmission FTIR spectroscopy results, and develop a method to correct the ATR-FTIR spectrum to accurately determine the solvation structures around Li+ ions.

Factors to consider before choosing EV labeling method for fluorescence-based techniques.

A well-designed fluorescence-based analysis of extracellular vesicles (EV) can provide insights into the size, morphology, and biological function of EVs, which can be used in medical applications. Fluorescent nanoparticle tracking analysis with appropriate controls can provide reliable data for size and concentration measurements, while nanoscale flow cytometry is the most appropriate tool for characterizing molecular cargoes. Label selection is a crucial element in all fluorescence methods. The most comprehensive data can be obtained if several labeling approaches for a given marker are used, as they would provide complementary information about EV populations and interactions with the cells. In all EV-related experiments, the influence of lipoproteins and protein corona on the results should be considered. By reviewing and considering all the factors affecting EV labeling methods used in fluorescence-based techniques, we can assert that the data will provide as accurate as possible information about true EV biology and offer precise, clinically applicable information for future EV-based diagnostic or therapeutic applications.

Radon Equilibrium Factor and the Assessment of the Annual Effective Dose at Underground Workplaces

The equilibrium factor F is one of the parameters that should be considered when assessing the effective dose based on radon activity concentration. Since the equilibrium factor in various environments ranges theoretically from a value close to 0 to 1, it is expected that dose assessment based on one recommended coefficient value may lead to an underestimation or overestimation of the dose. That is why it is essential to measure this quantity if the basis for dose assessment is the radon concentration and not the concentration of radon decay products. The equilibrium factors were determined based on measurements of radon activity concentration and potential alpha energy concentration and varied from 0.15 to 0.94, with an arithmetic mean of 0.55. The average effective dose calculated for the employee taking into account these values was 31 mSv, assuming an annual working time of 1800 h. In turn, the average effective dose calculated for the equilibrium factor of 0.2 as recommended by the International Commission on Radiological Protection (ICRP) was equal to 13 mSv.

A Sensor Probe with Active and Passive Humidity Management for In Situ Soil CO2 Monitoring.

Soil CO2 concentration and flux measurements are important in diverse fields, including geoscience, climate science, soil ecology, and agriculture. However, practitioners in these fields face difficulties with existing soil CO2 gas probes, which have had problems with high costs and frequent failures when deployed. Confronted with a recent research project's need for long-term in-soil CO2 monitoring at a large number of sites in harsh environmental conditions, we developed our own CO2 logging system to reduce expense and avoid the expected failures of commercial instruments. Our newly developed soil probes overcome the central challenge of soil gas probes-surviving continuous exposure to soil moisture while remaining open to soil gases-via three approaches: a 3D printed housing (economical for small-scale production) following design principles that correct the usual water permeability flaw of 3D printed materials; passive moisture protection via a hydrophobic, CO2-permeable PTFE membrane; and active moisture protection via a low-power micro-dehumidifier. Our CO2 instrumentation performed well and yielded a high-quality dataset that includes signals related to a prescribed fire as well as seasonal and diel cycles. We expect our technology to support underground CO2 monitoring in fields where it is already practiced and stimulate its expansion into diverse new fields.

COVID-19 and redemptions from Irish-resident bond funds

This paper examines net redemptions from bond funds domiciled in Ireland at the onset of the COVID-19 pandemic. We analyse various empirical specifications to determine whether factors such as fund leverage, measures of liquidity, portfolio risk and portfolio concentration, among others, explain outflows from Irish-domiciled bond funds in March 2020. The findings indicate that funds with a larger share of short-term securities and riskier bond portfolios experienced higher redemptions. Our analysis also suggests that fund size and age are significant factors affecting outflows. When examining various sub-samples, we find evidence of more reactive behaviour among investors in actively managed funds compared to passively managed funds. We also find that retail bond funds demonstrate greater sensitivity to risk and leverage, while professional funds show evidence of lower risk aversion. These results provide insights that can help inform policymakers’ view of regulatory tools for market-based finance, a key priority internationally.

Simultaneous measurement of temperature and C2H4 concentration in hydrocarbon flames using interference-immune differential absorption spectroscopy at 3.3 μm

In diagnostic applications based on tunable diode laser absorption spectroscopy, the measurement of target substances can be influenced by factors such as background thermal radiation in the combustion environment, extinction caused by solid or liquid particles, and other interfering absorptions. In this work, we developed a differential absorption diagnostic technique based on wavelength pairs, utilizing an interband cascade laser near 3.3 μm to simultaneously measure temperature and C2H4 concentration in hydrocarbon flames. Based on a detailed study of the C2H4 spectrum in this region and considering the optimal standard for spectral lines, two wavelength pairs were selected. The temperature is determined by the ratio of the absorption cross-sections of two wavelength pairs, and the C2H4 concentration is inferred based on the wavelength pair with higher differential absorption. In the initial stage, the system’s accuracy was verified in high-temperature static conditions (T = 300–800 K, P = 1 atm), and continuous time series measurements demonstrated the system’s stability. The limit of detection achieved by Allan-Werle variance analysis is 2.5 ppm at the optimal average time of 100 s. Subsequently, measurements were taken in a hydrocarbon flame. The obtained results indicate an average deviation of 1.021 % between the measured temperature in the flame and the reference value, with a standard deviation of 1.381 % for concentration measurement. All the measurements show that the system can be potentially applied to combustion diagnosis.

AI-based tree modeling for multi-point dioxin concentrations in municipal solid waste incineration

Numerous investigations have shown that the municipal solid waste incineration (MSWI) has become one of the major sources of dioxin (DXN) emissions. Currently, the primary issue that needs to be addressed for DXN emission reduction control is the online measurement of DXN. Data-driven AI algorithms enable real-time DXN concentration measurement, facilitating its control. However, researchers mainly focus on building models for DXN emissions at the stack. This approach does not allow for the construction of models that online measurement of DXN generation and absorption throughout the whole process. To achieve optimal pollution control, models that encompass the whole process are necessary, not just models focused on the stack. Therefore, this article focuses on modeling the whole process of DXN concentrations, including generation, adsorption, and emission. It uses machine learning techniques based on advanced tree-based data-driven deep and broad learning algorithms. The determination of data characteristics at different phases is grounded in the understanding of the DXN mechanism, offering a novel framework for DXN modeling. State-of-the-art tree-based models, including adaptive deep forest regression algorithm based on cross layer full connection, tree broad learning system, fuzzy forest regression, and aid modeling technologies, are applied to handle diverse data characteristics. These characteristics encompass high-dimensional small samples, low-dimensional ultra-small size samples, and medium-dimensional small samples across different phases related to DXN. The most interesting is the robust validation where the proposed a whole process tree-based model for DXN is validated using nearly one year of authentic data on DXN generation, adsorption, and emission phases in an MSWI plant of Beijing. The proposed modeling framework can be used to explore the mechanism characterization and support the pollution reduction optimal control.

Radiological monitoring and assessment of the radiation situation in the Kungur Ice Cave

This article presents the results of comprehensive radiological studies conducted in 2021 in order to assess the radiation situation in the Kungur Ice Cave (hereinafter referred to as the KIC). Since the cave is a fairly popular sightseeing object, therefore, the safety of both tourists and workers is a key task for scientific study. The radiation safety assessment was carried out taking into account the parameters of the radiation (gamma) background, measurements of radon and thoron concentrations, microclimatic indicators (air temperature, humidity), airflow rate, illumination and calculation of the indicator of a special assessment of working conditions (SAWC). Such comprehensive and detailed studies were conducted in the KIC for the first time, allowing some patterns to be identified and confirmed. For the indicators of gamma-activity and radon concentration, there is a clear dependence on the season of the year, which is directly related to microclimatic indicators, as well as to compliance with the ventilation regulations that have been established in the cave. The applied ventilation modes provide safe values of the radiation background and toron. In the summer months, the average radon content in the cave exceeds the maximum permissible concentrations by a factor of 7, which required calculation of the time of work in the cave. For the first time, special assessment of working conditions has been calculated for Kungur Ice Cave, but only for the winter period. The SAWC is defined for a working group consisting of engineers, workers and guides, taking into account such parameters as temperature, illumination, humidity, severity and intensity of labor and ionizing radiation (radiation background). According to preliminary data, the overall assessment of labor based on all parameters falls under the “harmful” class of conditions.

A novel electrochemical immunosensor based on AuNPs/PNR/CS@MWCNTs-COOH for rapid detecting warning markers-BNP of heart failure caused by myocardial infarction

Heart failure (HF) is an insidious and dangerous disease that significantly impairs a patient’s quality of life and safety. It is not easy to detect in mild cases, and once it progresses to severe stages, deterioration can be rapid and challenging to reverse. Currently, early warning and prognostic risk assessment technologies are lacking, and there is an urgent need for precise early warning, risk assessment and diagnosis and treatment of HF at the cellular or molecular level. In this study, an electrochemical immunosensor based on AuNPs/PNR/CS@MWCNTs-COOH was prepared to detect brain natriuretic peptide (BNP), a biomarker for early warning of HF caused by myocardial infarction. Among them, the CS@MWCNTs-COOH nanocomposites and the polymerized neutral red (PNR) films on the electrode surface effectively enhanced the conductivity of the modified electrodes and significantly increased the specific surface area through the formation of three-dimensional nanostructures. AuNPs loaded on PNR/CS@MWCNTs-COOH provided a stable gold-ammonia bond for the specific antibody loading of BNP, facilitating the development of an electrochemical immunosensor with high selectivity for BNP detection. Furthermore, this work used cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) to improve aspects that influence the immunosensor’s analytical performance. Under ideal conditions, the immunosensor was tested for immunological qualities using differential pulse voltammetry (DPV), resulting in sensitive measurement of BNP concentration in undiluted serum samples.The peak current Ip of the response signal is linearly proportional to the LgCBNP in the range of 1.95 × 10−3 ng mL−1 to 8.0 ng mL−1, with a detection limit of 0.80 × 10−3 ng mL−1 (S/N=3). It can achieve highly sensitive identification and detection of trace BNP in complex biological samples and provide a convenient and efficient method for HF-related marker detection. Furthermore, it also can serve as a scientific basis and a new method for the development of early warning technology for HF and related pathological mechanism research.

Simulating the Natural Seasonal Ventilation of a Classroom in Poland Based on Measurements of the CO2 Concentration

Simulating the Natural Seasonal Ventilation of a Classroom in Poland Based on Measurements of the CO2 Concentration

A new procedure to validate and optimize 210Po measurements in atmospheric aerosols

The exposure to air fine aerosols can cause health effects due to inhalations of alpha emitters such as 222Rn daughters. Lead-210 and 210Po are mainly associated to aerosols with median aerodynamic diameter lower than 1 μm. The 210Po is characterized by having a high radiotoxicity. The precise measurement of 210Po in surface air aerosols is usually quite complex due to the significant contribution of the 210Pb on their concentrations. Additionally, there is no possible means to manufacture a certified material to validate the measurements of 210Pb and 210Po concentrations in surface air aerosols. For these reasons, this study aims to develop a novel and comprehensive methodology to validate 210Po measurements in surface air aerosols by preparing in our laboratory “standard samples” with known activities of both 210Pb and 210Po. A detailed sensitivity analysis on the precision of 210Po concentration measurements has been carried out as a function of the involved variables such as sampling time, time elapsed between the sampling start and 210Po self-deposition and the 210Po/210Pb activity ratio in surface air aerosols. This study is necessary to find the optimum conditions for a precise measurement of 210Po in surface air aerosols. In addition, this methodology has been applied for the determination of 210Po concentrations in 30 samplings campaigns of atmospheric aerosols carried out at the El Carmen campus (Huelva province) from March 25th to July 15th, 2022. The results obtained for 210Pb and 210Po concentrations and atmospheric aerosol residence times (via 210Po/210Pb activity ratio) were consistent with other previous works.