Refinar búsqueda
Resultados 941-950 de 7,292
Arsenic accumulation in Pteris vittata: Time course, distribution, and arsenic-related gene expression in fronds and whole plantlets Texto completo
2022
Antenozio, Maria Luisa | Capobianco, Giuseppe | Costantino, Paolo | Vamerali, Teofilo | Bonifazi, Giuseppe | Serranti, Silvia | Brunetti, Patrizia | Cardarelli, Maura
In this work, arsenic (As) accumulation and distribution over time in Pteris vittata young fronds from adult plants and in whole plantlets, grown on a highly contaminated As-soil, was determined by μ-XRF. A linear increase in As content up to 60 days was found in young fronds at different times, and a progressive distribution from the apex to the base of the fronds was observed. In whole plantlets, As signal was detectable from 9 to 20 days in the apex of a few fronds and fiddleheads. Later, up to 60 days, As was localized in all fronds, in the rhizome and in basal part of the roots. The dynamics of expression of As-related genes revealed a good correlation between As content and the level of the As (III)-antiporter PvACR3 transcript in plantlets roots and fronds and in young fronds. Moreover, the transcription of As (V)-related gametophytic genes PvGAPC1, PvOCT4 increases over time during As accumulation while PvGSTF1 is expressed only in roots. Here, we demonstrate the suitability of the μ-XRF technique to monitor As accumulation, which allowed us to propose that As is initially directly transported to fiddleheads and apex of fronds, is later distributed to the whole fronds and simultaneously accumulated in the rhizome and roots. We also provide indications on the expression of candidate genes possibly involved in As (hyper)accumulation.
Mostrar más [+] Menos [-]Glycine ameliorates MBP-induced meiotic abnormalities and apoptosis by regulating mitochondrial-endoplasmic reticulum interactions in porcine oocytes Texto completo
2022
Gao, Lepeng | Zhang, Chang | Yu, Sicong | Liu, Shuang | Wang, Guoxia | Lan, Hainan | Zheng, Xin | Li, Suo
Monobutyl phthalate (MBP) is the main metabolite of dibutyl phthalate (DBP) in vivo. MBP has a stable structure, can continuously accumulate in living organisms, and has the potentially to harm animal and human reproductive function. In the ovarian follicle microenvironment, MBP may lead to defects in follicular development and steroid production, abnormal meiotic maturation, impaired ovarian function and other reproductive deficits. In this study, SMART-seq was used to investigate the effects of MBP exposure on the in vitro maturation (IVM) and development of porcine oocytes. The results showed that differentially expressed genes after MBP exposure were enriched in the biological processes cytoskeleton, cell apoptosis, endoplasmic reticulum (ER) and mitochondria. Glycine (Gly) improved the developmental potential of porcine oocytes by regulating mitochondrial and ER function. The effect of Gly in protecting oocytes against MBP-induced damage was studied. The results showed that the addition of Gly significantly decreased the rate of MBP-induced spindle abnormalities, decreased the frequency of MBP-induced mitochondria-associated ER membrane (MAM) interactions, and downregulated the protein and gene expression of the linkage molecules Mitofusin 1 (MFN1) and Mitofusin 2 (MFN2) in the MAM. Additionally, treatment with Gly restored the distribution of the 1,4,5-triphosphate receptor 1 (IP₃R1) and voltage-dependent anion channel 1 (VDAC1), further decreasing the intracellular free calcium concentration ([Ca²⁺]ᵢ) levels and mitochondrial Ca²⁺ ([Ca²⁺]ₘ) , increasing the ER Ca²⁺ ([Ca²⁺]ER) levels, and thus significantly increasing the ER levels and mitochondrial membrane potential (ΔΨ m). Gly also decreased the levels of reactive oxygen species (ROS) and increased the levels of Glutathione (GSH), oocyte apoptosis-related indicators (Caspase-3 activity and Annexin V) and oocyte apoptosis-related genes (BAX, Caspase 3 and AIFM1). Our results suggest that Gly can ameliorate microtubule cytoskeleton abnormalities and improve oocyte maturation by reducing the defective mitochondrial–ER interactions caused by MBP exposure in vitro.
Mostrar más [+] Menos [-]The inhibition effect of bank credits on PM2.5 concentrations: Spatial evidence from high-polluting firms in China Texto completo
2022
Yang, Fuyong | Xu, Qingsong | Li, Kunming | Yuen, Kum Fai | Shi, Wenming
Particulate Matter (PM₂.₅) pollution in China has been a primary concern for public health in recent years, which requires banks to appropriately control their credit supply to industries with high pollution, high energy consumption, and surplus capacity. For this reason, this paper examines economic determinants of PM₂.₅ concentrations and incorporates the spatial spillover effect of bank credit by employing the spatial Durbin model (SDM) under the stochastic impacts by regression on population, affluence and technology framework. Using China's provincial dataset from 1998 to 2016, the main findings are as follows: First, there is evidence in support of spatial dependence of PM₂.₅ concentrations and their inverted U-shaped relationship with economic growth in China. Second, PM₂.₅ concentrations in a province tend to increase as the level of its own urbanization increases, but they decrease as its own human capital and bank credit increase. Meanwhile, the level of neighboring urbanization positively influences a province's PM₂.₅ concentrations, whereas neighboring population size, industrialization, trade openness, and bank credit present negative impacts. Third, indirect effects of the SDM indicate significant and negative spatial spillover effect of bank credit on PM₂.₅ concentrations. These findings implicate policies on reforming economic growth, urbanization, human capital and bank credit to tackle PM₂.₅ pollution in China from a cross-provincial collaboration perspective.
Mostrar más [+] Menos [-]Characterization of the vertical variation in indoor PM2.5 in an urban apartment in China Texto completo
2022
Ainiwaer, Subinuer | Chen, Yilin | Shen, Guofeng | Shen, Huizhong | Ma, Jianmin | Cheng, Hefa | Tao, Shu
Indoor air pollution has aroused increasing concerns due to its significant adverse health impacts. Indoor PM₂.₅ exposure assessments often rely on PM₂.₅ concentration measured at a single height, which overlooks the vertical variation of PM₂.₅ concentrations accompanied by various indoor activities. In this study, we characterize the vertical profile of PM₂.₅ concentration by monitoring PM₂.₅ concentration at eight different heights in the kitchen and the bedroom, respectively, using low-cost sensors with high temporal resolution. The localized enhancement of PM₂.₅ concentration in elevated heights in the kitchen during cooking was observed on clean and polluted days, showing dominating contribution from cooking activities. The source contribution from cooking and outdoor penetration was semi-quantified using regression models. Stratified source contribution from cooking activities was evident in the kitchen during the cooking period. The contribution in elevated heights (above 170 cm) almost tripled the contrition in bottom layers (below 140 cm). In contrast, little vertical variation was observed during other times of the day in the kitchen or the bedroom. The exposure level calculated using the multi-height measurement in this study is consistently higher than the exposure level estimated from the single-height (at 110 cm) measurement. A more significant discrepancy existed for the cookers (17.8%) than the non-cookers (13.5%). By profiling the vertical gradient of PM₂.₅ concentration, we show the necessity to conduct multi-height measurements or proper breathing-height measurements to obtain unbiased concentration information for source apportionment and exposure assessment. In particular, the multi-height measuring scheme will be crucial to inform household cooking emission regulations.
Mostrar más [+] Menos [-]Long-term trends in particulate matter from wood burning in the United Kingdom: Dependence on weather and social factors Texto completo
2022
Font, A. | Ciupek, K. | Butterfield, D. | Fuller, G.W.
Particulate matter from wood burning emissions (Cwₒₒd) was quantified at five locations in the United Kingdom (UK), comprising three rural and two urban sites between 2009 and 2021. The aethalometer method was used. Mean winter Cwₒₒd concentrations ranged from 0.26 μg m⁻³ (in rural Scotland) to 1.30 μg m⁻³ (London), which represented on average 4% (in rural environments) and 5% (urban) of PM₁₀ concentrations; and 8% of PM₂.₅. Concentrations were greatest in the evenings in winter months, with larger evening concentrations in the weekends at the urban sites. Random-forest (RF) machine learning regression models were used to reconstruct Cwₒₒd concentrations using both meteorological and temporal explanatory variables at each site. The partial dependency plots indicated that temperature and wind speed were the meteorological variables explaining the greatest variability in Cwₒₒd, with larger concentrations during cold and calm conditions. Peaks of Cwₒₒd concentrations took place during and after events that are celebrated with bonfires. These were Guy Fawkes events in the urban areas and on New Year's Day at the rural sites; the later probably related to long-range transport. Time series were built using the RF. Having removed weather influences, long-term trends of Cwₒₒd were estimated using the Theil Sen method. Trends for 2015–2021 were downward at three of the locations (London, Glasgow and rural Scotland), with rates ranging from −5.5% year⁻¹ to −2.5% year⁻¹. The replacement of old fireplaces with lower emission wood stoves might explain the decrease in Cwₒₒd especially at the urban sites The two rural sites in England observed positive trends for the same period but this was not statistically significant.
Mostrar más [+] Menos [-]Microplastics as vectors of radioiodine in the marine environment: A study on sorption and interaction mechanism Texto completo
2022
Rout, Sabyasachi | Yadav, Sonali | Joshi, Vikram | Karpe, Rupali | Pulhani, Vandana | Kumar, A.V.
Radioiodine is one of the long-lived fission products and also an important radionuclide released during nuclear accidents, which generates interest in its environmental fate. Its sorption has been studied in a wide range of materials, but no equivalent study exists for microplastics, an emerging environmental vector. Weathering and biofilm formation on microplastics can enhance radioiodine sorption. For the first time, we're reporting how radioiodine interacts with different types of polyethylene derived microplastics (pristine, irradiated, and biofilm developed microplastics). This study revealed that exposure to radiation and the marine environment significantly alters the physico-chemical properties of microplastics. In particular, in marine-exposed samples, a signature of biofilm development was detected. Speciation study indicates that iodine exists in the iodide form in the studied marine environment. The study revealed that, iodide ions attach to biofilm-developed microplastics via electrostatic, ion-dipole, pore filling, and van der Waals interactions. Pore filling, ion-dipole, and van der Waals interactions may cause iodide binding to irradiated microplastics, whereas pore-filling and van der Waals interactions cause iodide binding to pristine microplastics. The distribution coefficient (Kd) of iodine on microplastics is positively correlated with biofilm biomass, which signifies the role of biofilm in radioiodine uptake. The Kd indicates microplastics are potential iodide accumulators and could be a possible vector in the marine system.
Mostrar más [+] Menos [-]Development and validation of a new scale to assess air quality knowledge (AQIQ) Texto completo
2022
Del Ponte, Alessandro | Ang, Lina | Li, Lianjun | Lim, Noah | Tam, Wilson Wai San | Seow, Wei Jie
Air pollution is a leading public health concern around the world. Assessing the public's knowledge about air quality is critical to calibrate public health interventions. However, previous efforts to measure knowledge about air quality (AQIQ) have not relied on consistent and validated measures, thus precluding cross-country comparisons. We aimed to develop a robust scale to assess AQIQ and tested it in multiple countries. To evaluate the psychometric properties and select the best performing items out of 10 AQIQ questions, we used methods from classical test theory and item response theory. We evaluated the scales using several scalability measures, including the Kuder-Richardson Formula 20 (KR-20), Loevinger's H, as well as trace lines. Volunteers from the United States (US, n = 400), India (n = 403), and China (n = 443) were recruited to validate the scale. Multiple linear regression was used to estimate the association between demographic factors and AQIQ. We found that participants from India had the highest AQIQ. In addition, not all questions performed well in each country. The scale was pruned and shorter subscales were validated. In the US, we obtained a 4-item scale (KR20 = 0.53, Loevinger's H = 0.34). In India, we obtained a 6-item scale (KR20 = 0.56; Loevinger's H = 0.48 for just 2 items). In China, we obtained a 5-item scale (KR20 = 0.39; Loevinger's H = 0.41 for just 2 items). Compared to the 10-item scale, the pruned scales showed stronger associations between measures of socioeconomic status and AQIQ. The results were robust to the scale used. Overall, general knowledge questions measured AQIQ more effectively in the US and India whereas knowledge of the air quality index better measured AQIQ in China. The findings suggest that careful measurement and validation are essential to develop knowledge scales for use in public health and environmental research.
Mostrar más [+] Menos [-]Mercury may reduce the protective effect of sea fish consumption on serum triglycerides levels in Chinese adults: Evidence from China National Human Biomonitoring Texto completo
2022
Wu, Bing | Qu, Yingli | Lu, Yifu | Ji, Saisai | Ding, Liang | Li, Zheng | Zhang, Miao | Gu, Heng | Sun, Qi | Ying, Bo | Zhao, Feng | Zheng, Xulin | Qiu, Yidan | Zhang, Zheng | Zhu, Ying | Cao, Zhaojin | Lv, Yuebin | Shi, Xiaoming
Sea fish contain omega-3 polyunsaturated fatty acids (omega-3 PUFAs) which have been found to reduce triglyceride (TG) levels. However, sea fish may contain pollutants such as mercury which cause oxidative stress and increase TG levels. Therefore, the relationship between sea fish and TG remains unclear. We aimed to explore whether blood mercury (BHg) can affect the effect of sea fish consumption frequency on TG level among Chinese adults. A total of 10,780 participants were included in this study. BHg levels were measured using inductively coupled plasma mass spectrometry (ICP-MS). The associations of sea fish consumption frequency with BHg and TG levels as well as the association of BHg with TG levels were evaluated using multiple linear regression. Causal mediation analysis was used to evaluate the mediation effect of BHg levels on the association of sea fish consumption frequency with TG levels. The frequency of sea fish consumption showed a negative association with TG level. Compared with the participants who never ate sea fish, the TG level decreased by 0.193 mmol/L in those who ate sea fish once a week or more [β (95%CI): −0.193 (−0.370, −0.015)]. Significant positive associations were observed of BHg with TG levels. With one unit increase of log2-transformed BHg, the change of TG level was 0.030 mmol/L [0.030 (0.009, 0.051)]. The association between sea fish consumption and TG was mediated by log2-transformed BHg [total effect = −0.037 (−0.074, −0.001); indirect effect = 0.009 (0.004, 0.015)], and the proportion mediated by log2-transformed BHg was 24.25%. BHg may reduce the beneficial effect of sea fish consumption frequency on TG levels among Chinese adults. Overall, sea fish consumption has more benefits than harms to TG.
Mostrar más [+] Menos [-]Geostationary satellite-derived ground-level particulate matter concentrations using real-time machine learning in Northeast Asia Texto completo
2022
Park, Seohui | Im, Jungho | Kim, Jhoon | Kim, Sang-min
Rapid economic growth, industrialization, and urbanization have caused frequent air pollution events in East Asia over the last few decades. Recently, aerosol data from geostationary satellite sensors have been used to monitor ground-level particulate matter (PM) concentrations hourly. However, many studies have focused on using historical datasets to develop PM estimation models, often decreasing their predictability for unseen data in new days. To mitigate this problem, this study proposes a novel real-time learning (RTL) approach to estimate PM with aerodynamic diameters of <10 μm (PM₁₀) and <2.5 μm (PM₂.₅) using hourly aerosol data from the Geostationary Ocean Color Imager (GOCI) and numerical model outputs for daytime conditions over Northeast Asia. Three schemes with different weighting strategies were evaluated using 10-fold cross-validation (CV). The RTL models, which considered both concentration and time as weighting factors (i.e., Scheme 3) yielded consistent improvement for 10-fold CV performance on both hourly and monthly scales. The real-time calibration results for PM₁₀ and PM₂.₅ were R² = 0.97 and 0.96, and relative root mean square error (rRMSE) = 12.1% and 12.0%, respectively, and the 10-fold CV results for PM₁₀ and PM₂.₅ were R² = 0.73 and 0.69 and rRMSE = 41.8% and 39.6%, respectively. These results were superior to results from the offline models in previous studies, which were based on historical data on an hourly scale. Moreover, we estimated PM concentrations in the ocean without using land-based variables, and clearly demonstrated the PM transport over time. Because the proposed models are based on the RTL approach, the density of in-situ monitoring sites could be a major uncertainty factor. This study identified that a high error occurred in low-density areas, whereas a low error occurred in high-density areas. The proposed approach can be operated to monitor ground-level PM concentrations in real-time with uncertainty analysis to ensure optimal results.
Mostrar más [+] Menos [-]Toxicity of historically metal(loid)-contaminated soils to Folsomia candida under the influence of climate change alterations Texto completo
2022
Silva, Ana Rita R. | Malheiro, Catarina | Loureiro, Susana | González-Alcaraz, M Nazaret
Global warming is drastically altering the climate conditions of our planet. Soils will be among the most affected components of terrestrial ecosystems, especially in contaminated areas. In this study we investigated if changes in climate conditions (air temperature and soil moisture) affect the toxicity of historically metal(loid)-contaminated soils to the invertebrate Folsomia candida, followed by an assessment of its recovery capacity. Ecotoxicity tests (assessing survival, reproduction) were performed in field soils affected by metal(loid)s under different climate scenarios, simulated by individually changing air temperature or soil moisture conditions. The scenarios tested were: standard conditions (20°C + 50% soil water holding capacity-WHC); increased air temperature (daily fluctuation of 20–30°C + 50% WHC); soil drought (20°C + 25% WHC); soil flood (20°C + 75% WHC). Recovery potential was assessed under standard conditions in clean soil. Increased temperature was the major climate condition negatively affecting collembolans performance (decreased survival and reproduction), regardless of metal(loid) contamination. Drought and flood conditions presented less pronounced effects. When it was possible to move to the recovery phase (enough juveniles in exposure phase), F. candida was apparently able to recover from the exposure to metal(loid) contamination and/or climate alterations. The present study showed that forecasted climate alterations in areas already affected by contamination should be considered to improve environmental risk assessment.
Mostrar más [+] Menos [-]