Long-term Exposure Research Articles

Effect of Phase Composition Variation of Oxy–Nitride Composite Ceramics on Heat Resistance and Preservation of Strength Parameters

The aim of this study is to determine the effect of changes in the phase composition of Al2O3–Si3N4 ceramics that were obtained using the method of mechanochemical solid-phase grinding on their resistance to the process of long-term thermal exposure, accompanied by the processes of oxidation and softening. The relevance of this research consists of determining the influence of the phase composition of ceramics on the change in their strength and thermophysical parameters, on the basis of which, we can draw a conclusion about the optimal composition of composite ceramics that have great prospects in the field of fire-resistant, heat-resistant, or radiation-resistant structural materials. During this study, the dynamics of the changes in the phase transformations of the xAl2O3–(1−x)Si3N4 ceramics, with variations in the ratio of the components, initiated by the thermal annealing of the samples, was established. According to the assessment of the phase transformations with variations in the ratio of the components, it was found that thermal annealing in an air environment at an Al2O3 concentration in the order of 0.3–0.5 M leads to the formation of an orthorhombic Al2(SiO4)O phase and an elevation in its contribution at concentrations above 0.5 M, which causes a rise in the thermophysical parameters and resistance to high-temperature degradation. During the heat resistance tests, it was found that the formation of the composite ceramics with the Si3N4(SiO2)/Al2(SiO4)O/Al2O3 phase composition results in an increase in the stability of their strength properties when exposed to thermally induced oxidation, which has a negative impact on their resistance to softening and a decrease in hardness. Moreover, the presence of the Al2(SiO4)O phase in the composition of the ceramics causes a slowdown in the processes of thermal oxidation of the Si3N4 phase under prolonged temperature exposure, alongside an increase in the degradation resistance of strength properties by more than 4–7 times, in comparison with the softening data established for single-component ceramics.

Glucocorticoid sparing effect of Janus Kinase inhibitors compared to biological Disease Modifying Anti-Rheumatic Drugs in rheumatoid arthritis, a single-center retrospective analysis.

Glucocorticoid sparing in rheumatoid arthritis (RA) treatment is crucial to minimizing adverse effects associated with long-term use. Janus kinase inhibitors (JAKi) could potentially offer a more potent glucocorticoid-sparing effect than biological Disease-Modifying Antirheumatic Drugs (bDMARDs). This is a single-center retrospective analysis of RA patients treated with JAKi or bDMARDs. Glucocorticoid tapering, rescue therapy and discontinuation were analyzed through mixed-effects models, Poisson regression, and multivariable logistic regression, respectively, adjusting for baseline disease activity, demographic factors, and treatment line. A total of 716 RA patients treated with JAKi (n = 156) or bDMARDs (n = 560) were evaluated. JAKi treatment was associated with a more rapid reduction in glucocorticoid dose within the first 6 months and 60% higher odds of discontinuation compared with bDMARDs (adjusted odds ratio 1.63, 95% CI 1.02-2.60, p 0.039). Despite a higher baseline glucocorticoid dose, over 50% of JAKi-treated patients discontinued glucocorticoids after 12 months, vs ∼40% for bDMARDs. The need for glucocorticoid rescue therapy was significantly higher in the bDMARD group (rate ratio 2.66 (95% CI, 1.88-3.74)). Our findings indicate that JAK inhibitors facilitate more rapid glucocorticoid tapering compared with bDMARDs in RA patients. These results underscore the potential of JAK inhibitors to reduce long-term glucocorticoid exposure, highlighting their value in RA management strategies, including minimizing glucocorticoid-related adverse effects.

Exposure effects of benzalkonium chloride (BAC) on gonadal physiology and fertility suppression in medaka (Oryzias latipes)

Benzalkonium chloride (BAC), a commonly used quaternary ammonium compound in various products like antiseptics, cosmetics, and disinfectants, has raised concerns due to its potential to contaminate aquatic environments and subsequently affect the reproductive performance of the organisms within those ecosystems. The article underscores a critical concern regarding the impact of BAC on aquatic ecosystems, particularly its effect on fish reproductive quality, using medaka (Oryzias latipes) as a model organism. Firstly, while measuring lethal dose of BAC in adult medaka, we observed a dose dependent mortality in BAC treated fish (100 and 200 ppm: 100%; 60 ppm: 51.7%; 30 ppm or less: no mortality at 24 h post treatment (hpt)) and calculated the LD50 at 96 hpt as 39.291 ppm (95% confidence interval: 28.817–53.570 ppm). Further, we assessed the molecular, cellular and histological changes through long-term exposure. Enlarged sperm pockets and reduced spermatocyte were seen in BAC exposed testis while no significant structural changes were observed in the ovaries. Following BAC exposure, drastic alterations in the gene expression and cellular localization related to sex, estrogen signaling, and autophagy were also noted from gonads and liver. Subsequently, using a short-term exposure analysis, we confirmed the sex and time responsive transcriptional kinetics and found that BAC sequentially affected the gonadal somatic cells followed by germ cell differentiation. Finally, using reproductively competent male and female medaka, we conducted progeny production and performance analysis and depicted a drastic reduction in fecundity, and fertilization and hatching rate, indicating adverse effects of BAC on reproductive success. Cumulatively, these findings emphasize the consequences of widespread use of BAC on reproductive security of aquatic animals and highlights the need for further research to comprehend the potential harm posed by such compounds to aquatic animal health and ecosystem integrity.

Destructive effect of UV-C light radiation on lettuce growth: risk assessment of long time exposure

Ultraviolet C (UV-C) light technology employs a particular wavelength within the ultraviolet spectrum to deactivate microorganisms, utilizing radiation as its method. UV-C light possesses germicidal properties, effectively disrupting the DNA of microorganisms such as bacteria, viruses and various pathogens, thereby impeding their ability to replicate and induce illness. Additionally, UV-C could enhance the production of phytochemicals and prevent contamination in agricultural applications. However, overexposure to UV-C can cause safety issues, especially for operators handling its utilization in germicidal or sterilization applications. This study investigated the destructive effects of UV-C light on the morphology and chlorophyll content of lettuces exposed to various durations, aiming to assess the risks associated with prolonged exposure. The results showed that prolonged UV-C exposure affects morphological and chlorophyll content changes. The most damaging effect on lettuce morphology and chlorophyll content was found in the 2 h of UV-C exposure treatment. In the 2 h of UV-C exposure treatment, lettuce length was reduced from 6.01 ± 0.80 cm on day 2 to 5.55 ± 0.78 cm on day 3. The lowest fresh weight of lettuce was also found at 2 h of UV-C exposure treatment (4.32 ± 0.94 gr). In addition, the lowest total lettuce stomata aperture was found in 2 h of UV-C treatment (41 units). Furthermore, on day 4, after 2 h of UV-C exposure treatments, the chlorophyll a, chlorophyll b and total chlorophyll content in lettuces were found to be 1.59 ± 0.02 mg g−1 FW, 0.93 ± 0.02 mg g−1 FW and 2.52 ± 0.04 mg g−1 FW, respectively. Therefore, the most destructive effect of UV-C was found during 2 h of UV-C exposure treatment. These findings indicate the dangers of long-term UV-C exposure to lettuce. Practically, this could also have a negative impact on humans. The knowledge gleaned from these findings is useful for safety issues in the industrial application of UV-C.

Association Between Long-Term Exposure to Environmental Fine Particulate Matter and the Prevalence of Thyroid Disorders: A National Cross-Sectional Study in China.

Background: Exposure to particles with an aerodynamic diameter of ≤2.5 μm (PM2.5) is associated with the occurrence of thyroid dysfunction among pregnant women and neonates, but it is not known if this association occurs in the general population. We aimed to determine the association of prolonged exposure to PM2.5 with the prevalence of thyroid disorders among adults in China. Methods: A nationally representative cross-sectional study of thyroid disorders, iodine status, and diabetes status was carried out in all 31 provinces across China from 2015 to 2017. In total, 73,900 adults aged 18 years and older were included. Serum concentrations of thyroid hormones, thyrotropin, and thyroid antibodies and the urine iodine concentration were measured. The environmental concentration of PM2.5 for each participant's residential address at a spatial resolution of 1 × 1 km was estimated. Results: The average long-term exposure to PM2.5 at residential addresses was 66.41 μg/m3, ranging from 17.58 μg/m3 to 120.40 μg/m3. Compared with that of individuals with lower exposure levels, the prevalence of thyroid diseases such as autoimmune thyroiditis and subclinical hypothyroidism was greater in those with PM2.5 concentrations within the third quartile range (60.18 to 73.78 μg/m3). Compared with those in the first quartile (17.58 to 46.38 μg/m3), participants in the highest PM2.5 quartile (73.78 to 120.40 μg/m3) presented an increased risk of overt hypothyroidism (OR 1.23 [CI 0.94-1.61]), subclinical hypothyroidism (1.10 [1.01-1.21]), autoimmune thyroiditis (1.09 [1.00-1.18]), and thyroglobulin antibody positivity (1.17 [1.07-1.29]). However, there was no association between PM2.5 exposure and overt hyperthyroidism, subclinical hyperthyroidism, Graves' disease, or thyroid peroxidase antibody positivity (p > 0.05). Each 10 μg/m³ increase in the PM2.5 concentration was associated with an increased risk of overt hypothyroidism (OR 1.05 [1.00-1.11]), subclinical hypothyroidism (1.02 [1.00-1.03]), and thyroglobulin antibody positivity (1.02 [1.00-1.04]). Furthermore, a nearly linear exposure-response relationship was observed between long-term PM2.5 exposure and thyroglobulin antibody positivity. Conclusions: PM2.5 exposure was associated with thyroid disorders among Chinese adults. A dose-response relationship between PM2.5 exposure and autoimmune thyroiditis, as well as thyroglobulin antibody positivity, was also observed.

Exposure modes determined the effects of nanomaterials on antibiotic resistance genes: The different roles of oxidative stress and quorum sensing

The effects of co-occurrent pollutants on antibiotic resistance genes (ARGs) in wastewater treatment plants (WWTPs) have raised attentions. However, how the different realistic exposure scenarios determining the effects of nanomaterials (NMs) on ARGs, was still unknown. Herein, the effects of NMs on ARGs under two realistic scenarios was investigated by short-term and long-term exposure modes. The presence of NMs with two different exposure modes could both promote the dissemination of ARGs, and the results were dose-, type- and duration-dependent. Compared to short-term exposure, the long-term exposure increased the abundances of ARGs with a greater extent except nano-ZnO. The long-term exposure increased the overall abundances of target ARGs by 2.9%–20.4%, while shot-term exposure caused the 3.4%–10.5% increment. The mechanisms of ARGs fates driven by NMs exposure were further investigated from the levels of microbial community shift, intracellular oxidative stress, and gene abundance. The variations of several potential bacterial hosts did not contribute to the difference in the ARGs transmission with different exposure modes because NMs types played more vital roles in the shift of microbial community compared to the exposure modes. For the short-term exposure, NMs were capable of triggering the QS by upregulating relevant genes, and further activated the production of surfactin and increased membrane permeability, resulting in the facilitation of ARGs transfer. However, NMs under long-term exposure scenario preferentially stimulated oxidative stress by generating more ROS, which then enhanced ARGs dissemination. Therefore, the exposure mode of NMs was one of the pivotal factors determining the ARGs fates by different triggering mechanisms. This study highlighted the importance of exposure scenario of co-occurrent pollutants on ARGs spread, which will benefit the comprehensive understanding of the actual environmental fates of ARGs.

Vicarious trauma and the COVID-19 pandemic: The role of organisations.

Vicarious trauma (VT) is an occupational challenge incurred through hearing about traumatic experiences of others such as child maltreatment, mass casualties, and others while serving in helping professions. Without sufficient resources and support, long-term exposure can lead to symptoms such as intrusion, avoidance, arousal, emotional numbing, anxiety, and decline in one's ability to work. Organisations can mitigate VT's impact by addressing the needs of staff through 5 evidence-informed areas of occupational health. This project explored the impact of VT-informed practices on organisational responses to the COVID-19 pandemic. We compared responses from 50 organisations on strengths and weaknesses in core areas of being VT-informed to how those organisations responded to the COVID-19 pandemic. Subscales of the VT Organizational Readiness Guide (VT-ORG) were utilized as the exposure variables and 4 new COVID-19 questions served as the outcome. We ran a series of multilevel linear regression models with clustering controlled for at the organisational level. Staff ratings on 4 of the 5 pillars of the VT-ORG were positively associated with the organisation's responsiveness to the pandemic. Various demographic factors of the employees were negatively associated with organisations' responsiveness to the pandemic. While this study contributes to the growing research on VT, it also provides justification for helping organisations to become VT-informed; it provides evidence that being prepared for VT can also be useful to support workers and their communities during emergencies such as the COVID-19 pandemic.

Visual detection of aldehyde gases using a silver-loaded paper-based colorimetric sensor array

The small molecule aldehydes are volatile organic compounds (VOCs), possessing cytotoxicity and carcinogenicity. Long-term exposure can pose a serious threat to human health. Based on an in-situ reduction colorimetric method to generate silver nanoparticles and induce colorimetric response, we proposed a silver-loaded paper-based colorimetric sensor array for visually detecting and differentiating five relatively common trace small molecule aldehyde gases. The silver ions are immobilized onto a porous filter paper and stabilized by complexing agents of branched polyethyleneimine, ethylenediamine, and 1,6-diaminohexane, respectively. The as-fabricated sensor array expresses remarkable stability and capacity to resist humidity. The qualitative analysis reveals that the sensor array has excellent selectivity for aldehyde gases and displays remarkable anti-interference ability. The quantitative analysis indicates that the sensor array exhibits superior sensitivity for five aldehyde gases, with limits of detection (LODs) of 9.0 ppb for formaldehyde (FA), 3.1 ppm for acetaldehyde (AA), 3.5 ppm for propionaldehyde (PA), 23.8 ppb for glutaric dialdehyde (GD), and 71.5 ppb for hydroxy formaldehyde (HF), respectively. Importantly, these LODs are all comfortably below their respective permissible exposure limits. A unique colorimetric response fingerprint is observed for each analyte. Standard chemometric methods illustrate that the sensor array has excellent clustering capability for these aldehyde gases. Additionally, the sensor array's response is irreversible and possesses outstanding performance for cumulative monitoring. This colorimetric sensor array based on silver ions reduced to silver nanoparticles offers a novel detection method for the continuous, ultrasensitive, and visual detection of trace airborne pollutants.

Triazine herbicide prometryn alters epoxide hydrolase activity and increases cytochrome P450 metabolites in murine livers via lipidomic profiling

Oxylipins are a group of bioactive fatty acid metabolites generated via enzymatic oxygenation. They are notably involved in inflammation, pain, vascular tone, hemostasis, thrombosis, immunity, and coagulation. Oxylipins have become the focus of therapeutic intervention since they are implicated in many conditions, such as nonalcoholic fatty liver disease, cardiovascular disease, and aging. The liver plays a crucial role in lipid metabolism and distribution throughout the organism. Long-term exposure to pesticides is suspected to contribute to hepatic carcinogenesis via notable disruption of lipid metabolism. Prometryn is a methylthio-s-triazine herbicide used to control the growth of annual broadleaf and grass weeds in many cultivated plants. The amounts of prometryn documented in the environment, mainly waters, soil and plants used for human and domestic consumption are significantly high. Previous research revealed that prometryn decreased liver development during zebrafish embryogenesis. To understand the mechanisms by which prometryn could induce hepatotoxicity, the effect of prometryn (185 mg/kg every 48 h for seven days) was investigated on hepatic and plasma oxylipin levels in mice. Using an unbiased LC–MS/MS-based lipidomics approach, prometryn was found to alter oxylipins metabolites that are mainly derived from cytochrome P450 (CYP) and lipoxygenase (LOX) in both mice liver and plasma. Lipidomic analysis revealed that the hepatotoxic effects of prometryn are associated with increased epoxide hydrolase (EH) products, increased sEH and mEH enzymatic activities, and induction of oxidative stress. Furthermore, 9-HODE and 13-HODE levels were significantly increased in prometryn treated mice liver, suggesting increased levels of oxidation products. Together, these results support that sEH may be an important component of pesticide-induced liver toxicity.

Evaluating the Effects of Long-Term Exposure to Fine Particulate Matter (PM2.5) on Depressive Mood among Korean Older Adults Using Multilevel Analysis.

The harmful effects of particulate matter (PM) are amplified in older adults, who experience a decline in physiological function, reducing their ability to expel and detoxify inhaled PM. Moreover, older adults may be more vulnerable to fine particulate toxicity due to underlying medical conditions. We assessed the effects of long-term exposure to fine particulate matter (PM2.5) on depressive mood (DM) in adults aged > 65 yr using community-based data. In the 2017, Korean Community Health Survey (KCHS) data, data of PM2.5 and community factors were constructed based on participants who responded to DM in a sample of 67,802 individuals. To evaluate the effect of PM2.5 on DM among older adults, a multilevel regression model was constructed using individual-(KCHS) and community-level data (PM2.5, green area per capita, urban area, social welfare budget, health, and social business). For PM2.5, an independent variable, quartiles were used to classify regions according to concentration. A positive correlation was found between PM2.5 and DM of older adults. Compared to Q1, the odds ratio increased to 1.15 (95% CI 0.76-1.74) in Q2, 1.55 (95% CI 1.02-2.35) in Q3, and 1.60 (95% CI 1.16-2.20) in Q4. DM may increase in older individuals living in areas with high PM2.5. Systematic mental health management is required for older individuals residing in such areas.

Long-term exposure to air pollution and the risks of venous thromboembolism: a nationwide population-based retrospective cohort study.

To delineate the effects of exposure to air pollution on the risk of venous thromboembolism (VTE). The association between air pollution and arterial occlusive diseases has been well reported in the literature. VTE is the third most common acute cardiovascular syndrome; however, its relationship with exposure to air pollution has been controversial. This study linked data from the Taiwan National Health Insurance Research Database with that from the Taiwan Environmental Protection Administration. Patients who were first admitted for VTE between January 1, 2001, and December 31, 2013, were analyzed. A time-stratified, case-crossover design was employed. Three different exposure periods were defined: exposure for 1month, one quarter, and 1year. Four control periods were designated for each exposure period. The association between exposure to air pollutants and the risk of VTE was tested using logistic regression analysis. Subgroup analyses were also performed, stratified by age, sex, type of VTE, the use of hormone therapy, and level of urbanization at the site of residence. Exposures to particulate matter (PM) smaller than 2.5µm (PM2.5) and those smaller than 10µm (PM10) were associated with higher risks of VTE, with longer exposures associated with higher risk. The concentration of PM2.5 exposure for 1month was linearly associated with a greater risk of VTE up to 28.0µg/m3, beyond which there was no association. PM2.5 exposure for one quarter or 1year remained significantly associated with higher risks of VTE at higher concentrations. The increased risk in VTE associated with exposure to PM2.5 was more prominent in older patients and in patients not under hormone therapy. Similar results were observed for PM10 exposures. Exposure to PM, particularly PM2.5, leads to an increased risk of VTE, with possible accumulative effects. With increased PM production in industrializing countries, the effects of PM on VTE occurrence warrant further attention.

Long-term Compressive Strength Properties of Concrete Incorporating Admixtures: Outdoor Exposure Testing in a Coastal Environment

In this study, concrete specimens were fabricated based on domestically manufactured materials, and long-term exposure tests were conducted in a domestic coastal environment. This study analyzes the long-term compressive strength characteristics of concrete mixed with admixtures. The mixed materials used were divided into blast furnace slag and fly ash. The blast furnace slag and fly ash were, respectively, produced by replacing ~ 30% and ~ 15% of the cement. The compressive strength was measured at 28 day, 1 year, and 10 years of age and compared with that of ordinary concrete. In addition, the long-term compressive strength results obtained in this study were compared with those of concrete mixed with admixtures reported in the literature. The strengths of the ordinary specimen at 1 year and 10 years of age increased by ~ 10 MPa and ~ 22 MPa compared with those at 28 day of age. However, concrete mixed with admixtures yielded compressive strength increases of ~ 5 MPa and ~ 26 MPa at 1 year and 10 years of age, respectively, compared with those at 28 day of age. A comparison of the compressive strengths of concrete mixed with admixtures reported in the literature (based on age) and those obtained in this study showed that there was an initial strength difference in the range of 10–25%. However, the compressive strength at 10 years of age was almost similar to those reported in the literature with differences of less than 5%. These findings confirmed that when using pozzolanic admixtures, the development rate of the initial strength may vary owing to various factors; however, the long-term strength converges within a certain range.

Long-term ambient ozone exposure and childhood asthma, rhinitis, eczema, and conjunctivitis: A multi-city study in China

Evidence on the link of long-term exposure to ozone (O3) with childhood asthma, rhinitis, conjunctivitis and eczema is inconclusive. We did a population-based cross-sectional survey, including 177,888 children from 173 primary and middle schools in 14 Chinese cities. A satellite-based spatiotemporal model was employed to assess four-year average O3 exposure at both residential and school locations. Information on asthma, allergic rhinitis, eczema and conjunctivitis was collected by a standard questionnaire developed by the American Thoracic Society. We used generalized non-linear and linear mixed models to test the associations. We observed linear exposure-response associations between O3 and all outcomes. The odds ratios of doctor-diagnosed asthma, rhinitis, eczema, and conjunctivitis associated with per interquartile increment in home-school O3 concentration were 1.31 (95 % confidence interval [CI]: 1.28, 1.34), 1.25 (95 %CI: 1.23, 1.28), 1.19 (95 %CI: 1.16, 1.21), and 1.28 (95 %CI: 1.21, 1.34), respectively. Similar associations were observed for asthma-related outcomes including current asthma, wheeze, current wheeze, persistent phlegm, and persistent cough. Moreover, stronger associations were observed among children who were aged > 12 years, physically inactive, and exposed to higher temperature. In conclusion, long-term O3 exposure was associated with higher risks of asthma, allergic rhinitis, conjunctivitis and eczema in children.

L1CAM mediates neuroendocrine phenotype acquisition in prostate cancer cells.

A specific type of prostate cancer (PC) that exhibits neuroendocrine (NE) differentiation is known as NEPC. NEPC has little to no response to androgen deprivation therapy and is associated with the development of metastatic castration-resistant PC (CRPC), which has an extremely poor prognosis. Our understanding of genetic drivers and activated pathways in NEPC is limited, which hinders precision medicine approaches. L1 cell adhesion molecule (L1CAM) is known to play an oncogenic role in metastatic cancers, including CRPC. However, the impact of L1CAM on NEPC progression remains elusive. L1CAM expression level was investigated using public gene expression databases of PC cohorts and patient-derived xenograft models. L1CAM knockdown was performed in different PC cells to study in vitro cell functions. A subline of CRPC cell line CWR22Rv1 was established after long-term exposure to abiraterone to induce NE differentiation. The androgen receptor-negative cell line PC3 was cultured under the tumor sphere-forming condition to enrich cancer stemness features. Several oxidative stress inducers were tested on PC cells to observe L1CAM-mediated gene expression and cell death. L1CAM expression was remarkably high in NEPC compared to CRPC or adenocarcinoma tumors. L1CAM was also correlated with NE marker expressions and associated with the adenocarcinoma-to-NEPC progression in gene expression databases and CRPC cells with NE differentiation. L1CAM also promoted cancer stemness and NE phenotypes in PC3 cells under cancer stemness enrichment. L1CAM was also identified as a reactive oxygen species-induced gene, by which L1CAM counteracted CRPC cell death triggered by ionizing radiation. Our results unveiled a new role of L1CAM in the acquisition of the NE phenotype in PC, contributing to the NE differentiation-related therapeutic resistance of CRPC.

Evaluation of Deep Learning Models for Predicting the Concentration of Air Pollutants in Urban Environments

Air pollution is an issue of great concern globally due to the risks to the health of humanity, animals, and ecosystems. On the one hand, air quality monitoring systems allow for determining the concentration level of air pollutants and health risks through an air quality index (AQI). On the other hand, accurate future predictions of air pollutant concentration levels can provide valuable information for data-driven decision-making to reduce health risks from short- and long-term exposure when indicators exceed permissible limits. In this paper, five deep learning architectures are evaluated to predict the concentration of particulate matter pollutants (in their fractions PM2.5 and PM10) and carbon monoxide (CO) in consecutive hours. The proposed prediction models are based on recurrent neural networks (RNNs), long short-term memory (LSTM), vanilla LSTM, Stacked LSTM, Bi-LSTM, and encoder–decoder LSTM networks. Moreover, a methodology is presented to guide the construction of the prediction model, encompassing raw data processing, model design and optimization, and neural network training, testing, and evaluation. The results underscore the precision and reliability of the Stacked LSTM model in predicting the hourly concentration level for PM2.5, with an RMSE of 3.4538 μg/m3. Similarly, the encoder–decoder LSTM model accurately predicts the concentration level for PM10 and CO, with an RMSE of 3.2606 μg/m3 and 2.1510 ppm, respectively. These evaluations, with their minimal differences in error metrics and coefficient of determination, validate the effectiveness and superiority of the deep learning models over other reference models, instilling confidence in their potential.

Dew points for hydrogen-rich (hydrogen + propane) and (hydrogen + n-butane) mixtures determined with a microwave re-entrant cavity resonator

Dew-point measurements were performed for hydrogen-rich binary mixtures with hydrocarbon mole fractions of 0.09995 C3H8, 0.1499 C3H8, 0.0513 n-C4H10, and 0.09888 n-C4H10 using a modified microwave re-entrant cavity apparatus. Isochoric measurements were conducted in the temperature range of (256 to 286) K with pressures up to 6.8 MPa and 2.0 MPa for mixtures containing propane and n-butane, respectively. The combined expanded uncertainties (k = 2) in dew-point temperature and pressure were estimated to be between (0.35 and 2.0) K and (0.0011 and 0.030) MPa. The agreement with predictions of the GERG-2008 equation of state is within 5.5%. However, better agreement with predicted values was achieved using a cubic equation recently developed in-house. Moreover, experiments with short- and long-term exposure of pressure sensors to hydrogen have shown that pressure measurement, and thus the uncertainty, can be affected; further investigation on this matter is therefore inevitable to improve hydrogen thermophysical property data.

Effect of anteroposterior vibration frequency on the risk of lumbar injury in seated individuals

Few studies investigate the impact of anterior-posterior excitation frequency on the time-domain vibrational response and injury risk of the lumbar spine in seated individuals. Firstly, this study utilised a previously developed finite element model of an upright seated human body on a rigid chair without a backrest to investigate the modes that affect the anterior-posterior vibrations of the seated body. Subsequently, transient dynamic analysis was employed to calculate the lumbar spine’s time-domain responses (displacement, stress, and pressure) and risk factors under anteroposterior sinusoidal excitation at varying frequencies (1–8 Hz). Modal analysis suggested the frequencies significantly affecting the lumbar spine’s vibration were notably at 4.7 Hz and 5.5 Hz. The transient analysis results and risk factor assessment indicated that the lumbar responses were most pronounced at 5 Hz. In addition, risk factor assessment showed that long-term exposure to 8 Hz vibration was associated with a greater risk of lumbar injury.

Estimating the Exposure-Response Function between Long-term Ozone Exposure and Under-five Child Mortality in Low- and Middle-Income Countries

Estimating the Exposure-Response Function between Long-term Ozone Exposure and Under-five Child Mortality in Low- and Middle-Income Countries

Long-term mercury exposure and visual field constriction in Grassy Narrows First Nation

Long-term mercury exposure and visual field constriction in Grassy Narrows First Nation

Long-term postnatal exposure to air pollution and routine vaccine antibody levels in children

Long-term postnatal exposure to air pollution and routine vaccine antibody levels in children