Typical Site Research Articles

The assembly process and co-occurrence patterns of soil microbial communities at a lead smelting site

The potential toxic elements of the site are diverse and complex, seriously threatening the land utilization potential and soil ecological function. Microbial community is critical to maintaining ecosystem function, their assembly processes and diversity play an essential role in predicting changes in soil ecological function. However, our understanding of the mechanisms that shape community composition and successional direction in complex polluted environments is very limited. In this study, to explore the mechanisms driving community assembly and symbiosis in different contaminated regional environments, the biological characteristics of bacterial and fungal communities in four different polluted areas of a typical lead smelting site were studied. Contamination by PTEs appears to increase microbial networks, as well as altering microbial community composition, with relative abundance of dominant phyla such as Actinomycetes and Acidobacteria decreasing, whilst Proteobacteria and Ascomycota increased, this indicated that communities may shift from K-strategy to r-strategy and become opportunistic. Dispersal limitation (DL, 42 %–86 %), drift (Dr, 8 %–37 %) and homogeneous selection (HoS, 1 %–31 %) proved to be the important community assembly process. The top ten bins controlling the contribution of different biological processes were identified, and the relative abundance of these bacterial and fungal taxa varied with CPI. Collectively, our results suggest that CPI and nutrient availability regulate soil bacterial and fungal community assembly processes. The results of this study provide potential guidance for community regulation in the process of ecological restoration and mitigating degraded soils at smelting sites.

Microtremor Recording Surveys to Study the Effects of Seasonally Frozen Soil on Site Response

Microtremor recording tests using an accelerometer were carried out in this paper with the aim of characterizing the effects of seasonally frozen soil on the seismic site response, including the two-direction microtremor spectrum, site predominant frequency, and site amplification factor. The study selected eight typical seasonal permafrost sites in China for site microtremor measurements during both summer and winter seasons. Based on the recorded data, the horizontal and vertical components of the microtremor spectrum, HVSR curves, site predominant frequency, and site amplification factor were calculated. The results showed that seasonally frozen soil increased the predominant frequency of the horizontal component of the microtremor spectrum, while the effect on the vertical component was less noticeable. It indicates that the frozen soil layer has a significant impact on the propagation path and energy dissipation of seismic waves in the horizontal direction. Furthermore, the peak values of the horizontal and vertical components of the microtremor spectrum decreased by 30% and 23%, respectively, due to the presence of seasonally frozen soil. The predominant frequency of the site increased by a maximum of 35% and a minimum of 2.8%, while the amplification factor decreased by a maximum of 38% and a minimum of 11%. Additionally, a relationship between the increased site predominant frequency and the cover thickness was proposed.

#2880 ASSESSMENT OF FLUID STATUS BY COMBINATION OF LUNG ULTRASOUND, BIOIMPEDANCE, AND INFERIOR VENA CAVA MEASUREMENT IN HEMODIALYSIS PATIENTS

Abstract Background and Aims Assessment of fluid status in hemodialysis patients (HD) remains a major challenge for nephrologists. Fluid overload is one of the most common modifiable risk factors directly associated with hypertension. The purpose of our study was to investigate whether the combination of three bedside methods-lung ultrasound comets (LUC), multifrequency bioimpedance (MBIS), and inferior vena cava diameter (IVCD) measurement-could provide complementary information to guide the management of HD patients. Method We assessed MBIS, LUC at 28 typical sites, and IVCD in 18 HD patients enrolled in the HD maintenance program. LUC and IVCD measurements were performed three times-before, during, and after HD, MBIS only before and after HD. For MBIS measurement, we used the Body Composition Monitor (Fresenius Medical Care, Bad Homburg, Germany), and for LUC and IVCD, we used an ultrasound machine (Esaote MyLabOmega, Genoa, Italy). Ultrafiltration during HD was not adjusted for LUC, IVCD, and MBIS. Overhydration (OH) was defined as > 2L with MBIS, > 15 LUC, and < 40% collapsibility index (CI) on IVCD. Results The mean age of participants was 61 (IQR, 47-74) years, and thirteen (72.2%) were male. The average dialysis vintage of our patients was 105 months (IQR, 30-155). According to the OH criteria before, during, and after HD, 13 (72%), 2 (11%) patients were overhydrated according to MBIS, 10 (56%), 7 (39%), 3 (17%) patients according to LUC, and 13 (72%), 12 (67%), and 11 (61%) patients according to CI. We found no correlation between systolic blood pressure (BP), diastolic BP, MBIS, LUC, and CI before, during, and after HD, except that systolic BP after HD correlated with MBIS (OH) after HD (r = 0.491; p = 0.039). Using the paired-samples T-test, we found a statistically significant difference between OH before and after HD (p < 0.001), between LUC before and during HD (p = 0.006), between LUC during and after HD (p = 0.002), and between LUC before and after HD (p < 0.001). Using the paired-samples T-test, no statistically significant difference was found between systolic, diastolic BP and CI before, during, and after HD. Conclusion Optimal assessment of fluid status in HD patients remains challenging and, according to our results, may require a combination of LUC and MBIS parameters.

Temporal dynamics and controlling factors of CO2 and CH4 variability in the urban atmosphere of Wroclaw, Poland

Temporal and spatial distribution of both biogenic and anthropogenic components of atmospheric carbon dioxide (CO2) and methane (CH4) is crucial for understanding the environmental impacts of climate change over urban areas. This research focuses on applying stable isotope source-partitioning studies to determine the interactions between biogenic and anthropogenic CO2 and CH4 emissions in an average-sized city environment. Study signifies the weight of instantaneous variability and diurnal averaging as compared with seasonal records of variations of the atmospheric CO2 and CH4 at a variety of typical urban sites in the city of Wroclaw, conducted during a one-year period from June 2017 to August 2018.The findings reveal distinct temporal variations in atmospheric CO2 and CH4 mole fractions and their isotopic composition. The average atmospheric CO2 and CH4 mole fractions during the study period were 416.4 ± 20.5 ppm, and 1.95 ± 0.09 ppm, respectively. The study highlights the high variability of driving forces, including current energy use patterns, natural carbon reservoirs, planetary boundary layer dynamics, and atmospheric transport. Additionally, the relationship between the evolution of the convective boundary layer depth and the CO2 budget was analyzed using the CLASS model with input parameters based on field observations, resulting in insights such as an increase in the range of 25–65 ppm of CO2 during stable nocturnal boundary layers.The observed changes in stable isotopic signatures of air samples allowed for the identification of two main source categories in the city area: fuel combustion and biogenic processes. The δ13C-CO2 values of collected samples suggest that biogenic emissions dominate (up to 60 % of CO2 excess mole fraction) during the growing season, but are reduced by plant photosynthesis during summer afternoons. In contrast, local fossil-fuel CO2 contribution (up to 90 % of excess CO2 mole fraction) from domestic heating, vehicle emissions, and heat and power plants predominantly influence the urban GHG budget during winter. The δ13C-CH4 values indicate anthropogenic sources related to fossil fuel combustion during winter, with values ranging from −44.2 ‰ to −51.4 ‰, while slightly more depleted values, between −47.1 ‰ and −54.2 ‰, reflect a larger input of biological processes in the methane urban budget during summer.Overall, instantaneous and hourly variability of the above-mentioned readings of gas mole fraction and isotopic composition, have shown higher variability than seasonal amplitudes. Hence, respecting this granularity is the key to alignment and understanding significance of such localized atmospheric pollution studies. Additionally, the changing overprint of the system's framework, such as variability of wind and atmospheric layering patterns, weather events, provides context of sampling and data analysis at different frequencies.

Optimization of residential urban-block morphology based on its synthetic effects on indoor and outdoor natural lighting environments

The qualities of indoor and outdoor natural lighting environments are important aspects of sustainable urban design, which are inseparable, especially in high-density cities. This study aimed to reveal the synthetic effects of mesoscale urban morphology on indoor and outdoor natural lighting environments and propose corresponding design strategies for the sustainability of cities. Through data mining, 1680 residential blocks in Hangzhou, China, were selected for simulation analysis; urban morphology indicators that have a significant influence on daylighting performance were extracted. A multi-objective optimization algorithm was adopted to explore the optimal morphological features of urban morphology within a typical site. The extracted features were verified by morphological modifications in real cases. 1) The floor area ratio had the most significant effect on indoor daylighting (p= -0.673), while density was the most influential indicator for outdoor environments (p= -0.406); 2) in a typical site, morphological optimization can effectively improve lighting quality, with the average daylighting factor and sky view factor increasing by 3.7 and 6.7%, respectively; 3) two design strategies can simultaneously improve the indoor and outdoor natural lighting: dispersing the overall building mass to the perimeter of the site and dispersing the slab buildings of large masses as much as possible.

Reconsideration of the Diagnostic Criteria for an Atypical Placental Site Nodule Comparing Typical Placental Site Nodule of the Uterus: A Report of Two Cases.

Placental site nodules (PSNs) are non-neoplastic remnants of chorionic-type intermediate trophoblastic cells from a previous gestation that form a well-defined single nodule or multiple nodules in the uterine and extrauterine sites. As the cases of PSNs transformed into gestational trophoblastic tumors were described in the literature, "atypical placental site nodules" (APSNs) have been considered as putative transitional lesions between PSNs and gestational trophoblastic tumors. Although histologic criteria and cutoff point of Ki-67 proliferation index for differentiating an APSN from a typical PSN have not been clearly defined, nodules larger than 5 mm with increased cellularity, a corded or nested appearance, marked nuclear atypia, increased mitotic activity, and an increased Ki-67 proliferation index (>5% or >8%) of intermediate trophoblastic cells seem to be accepted as diagnostic criteria for APSNs. However, some of the criteria, including lesion size and histologic features of the trophoblastic cells in the nodule are not only subjective but have features inherent of the intermediate trophoblastic cells of the fetal membrane and a typical PSN. We thought that it is not reasonable to consider them as diagnostic features of APSNs, if not associated with cellular proliferation. We present 2 cases of incidentally identified PSNs that were larger than 10 mm in size with a corded or nested arrangement of trophoblastic cells, which could have been categorized as APSNs according to the currently proposed criteria to discuss whether the currently proposed diagnostic criteria for APSNs are appropriate.

Investigating CT head diagnostic reference levels based on indication-based protocols – a single site study

IntroductionThis study aimed to provide clinically-relevant insights into establishing CT DRLs based on indication-based protocols in Ireland, focusing on CT head examinations performed at a neurology centre of excellence hospital. MethodsDose data were collected retrospectively. Typical values for six CT head indication-based protocols were established using a sample size of 50 patients for each protocol. Typical values for each protocol were set as the median of the distribution curve. Dose distributions for each protocol were calculated and compared using non-parametric median test (k-samples) to ascertain significant dose differences between the typical values. ResultsMost typical values pairings showed significant differences (p < 0.001) except between stroke/non-vascular brain, stroke/acute brain, and acute brain/non-vascular brain pairings. This was expected due to similar scan parameters. The typical value for stroke (3-phases angiogram) was 52% lower than the typical value for stroke. Dose levels of the male populations recorded were higher than female populations for all protocols. Statistical comparison showed significant differences for dose quantities and/or scan length between both genders in five protocols. ConclusionProposed values for DLP were up to 63% and 69% lower than the EU and Irish national DRLs respectively. Establishment of CT stroke DRLs should be based on the scan performed instead of number of scan acquisitions. Lastly, gender-based CT DRLs for specific protocols within the head region require further investigation. Implications for practiceWith increasing CT examinations worldwide, radiation dose optimisation is key. The value of indication based DRLs is to enhance the required patient protection so image quality can be maintained, however with relevant DRLs for varying protocols. Establishment of CT typical values and site specific DRLs for procedures beyond the national DRLs can drive dose optimisation locally.

Types and Source Apportionment of Polycyclic Aromatic Hydrocarbons (PAHs) in Soil-Groundwater of a Closed Coking Plant in Shanxi Province, China

To clarify the impact of coking industry activities on the soil-groundwater Polycyclic aromatic hydrocarbon (PAH) occurrence, a typical coking site in Shanxi Province was taken as the study area, and soil and groundwater samples were collected to analyze the pollution level, composition, and distribution of PAHs in soil-groundwater. The sources of PAHs in the study area were identified based on the positive matrix decomposition model (PMF); the health risks of PAHs were calculated based on the carcinogenic and non-carcinogenic health risk model from the Technical Guidelines for Risk Assessment of Soil Pollution for Construction Land (HJ 25.3-2019) and toxicity equivalent quantity (TEQ). The results showed that ∑PAHs of soil ranged from 0 to 6077.7 mg/kg, with an average value of 198.02 mg/kg; ∑PAHs of groundwater ranged from 0 to 18.30 mg/L, with an average value of 9.39 mg/L. In horizontal distribution, ∑PAH content and types in the tar processing area were much higher than those in the surrounding area, and PAHs might migrate to the southwest through infiltration; in vertical distribution, ∑PAH content reached a peak at 5 m underground. According to the PMF model results, four primary sources of ∑PAHs were identified, which were the coking production source (55.0%), coal and petroleum combustion source (22.6%), atmospheric deposition source (13.1%) and residents living source (9.3%). The total average ∑PAH carcinogenic and non-carcinogenic health risks of soil in the study area were 7.05 × 10−6 and 0.695; the average TEQBaP−∑PAHs was 1.650 mg·TEQ/g; as for groundwater, they were 3.08 × 10−6 and 32.04; the average TEQBaP−∑PAHs was 9.390 μg·TEQ/L, indicating that PAHs both in soil and groundwater had potential health risks. This study provides a basis for the same coking site type for pollution control, secondary utilization, and data support for future site restoration.

Feature fusion improves performance and interpretability of machine learning models in identifying soil pollution of potentially contaminated sites

Owing to the rapid development of big data technology, use of machine learning methods to identify soil pollution of potentially contaminated sites (PCS) at regional scales and in different industries has become a research hot spot. However, due to the difficulty in obtaining key indexes of site pollution sources and pathways, current methods have problems such as low accuracy of model predictions and insufficient scientific basis. In this study, we collected the environmental data of 199 PCS in 6 typical industries involving heavy metal and organic pollution. Then, 21 indexes based on basic information, potential for pollution from product and raw material, pollution control level, and migration capacity of soil pollutants were used to established the soil pollution identification index system. We fused the original indexes into the new feature subset with 11 indexes through the method of consolidation calculation. The new feature subset was then used to train machine learning models of random forest (RF), support vector machine (SVM), and multilayer perceptron (MLP), and tested to determine whether it improved the accuracy and precision of soil pollination identification models. The results of correlation analysis showed that the four new indexes created by feature fusion have the correlation with soil pollution is similar to the original indexes. The accuracies and precisions of three machine learning models trained on the new feature subset were 67.4%− 72.9% and 72.0%− 74.7%, which were 2.1%− 2.5% and 0.3%− 5.7% higher than these of the models trained on original indexes, respectively. When the PCS were divided into typical heavy metal and organic pollution sites according to the enterprise industries, the accuracy of the model trained on the two datasets for identifying soil heavy metal and organic pollution were significantly improve to approximately 80%. Owing to the imbalance in positive and negative samples in the prediction of soil organic pollution, the precisions of soil organic pollution identification models were 58%− 72.5%, which were significantly lower than their accuracies. According to the factors analysis based on the model interpretability of SHAP, most of the indexes of basic information, potential for pollution from product and raw material, and pollution control level had different degrees of impact on soil pollution. However, the indexes of migration capacity of soil pollutants had the least effect in the classification task of soil pollution identification of PCS. Among the indexes, traces of soil pollution, industrial utilization years/start-up time, pollution control risk scores and enterprise scale having the greatest effects on soil pollution with the mean SHAP values of 0.17–0.36, which reflected their contribution rate on soil pollution and could help to optimize the current index scoring of the technical regulation for identifying site soil pollution. This study provides a new technical method to identify soil pollution based on big data and machine learning methods, in addition to providing a reference and scientific basis for environmental management and soil pollution control of PCS.

Thermal or photovoltaic rear sides? A parametric comparison between photovoltaic thermal and bifacial technology

The photovoltaic generation has experienced high growth in recent years. However, more effort is needed to get on track with the net-zero scenario. The use of the photovoltaic modules' rear part can increase their electricity generation by controlling their temperature (hybrid photovoltaic/thermal solutions) or by adding conversion capability to the backside (bifacial modules). However, which solution is more effective in increasing energy yield, and under what conditions? To answer these questions, the authors conducted a worldwide comparative parametric study considering a wide range of site conditions and photovoltaic module specifications. Two relevant results came from the study. The first is a global technical competitive analysis to determine favorable site and module specifications for each rear-side utilization alternative. The second is the mathematical expression of a new parameter named “critical bifaciality,” which expresses the minimum bifaciality rate required to obtain a performance superior to similar monofacial photovoltaic-thermal modules. This parameter serves as a design rule for the selection specification of the bifacial system, which depends on both the location’s climate and site conditions. It also permits determining the feasible locations for adopting either technology based on electricity production. The study concludes that using bifacial modules is the most effective way to increase electricity generation. For typical site conditions (albedo = 0.3), module specifications (cell efficiency = 20%, and Temperature coefficient (-0.3%/°C), the energy benefit can range from 1 to 5% near the equator and more than 25% near the poles.

Absence of secondary osteons in femora of aged rats: Implications of lifespan on Haversian remodeling in mammals.

Bone is a dynamic tissue capable of adapting to its loading environment, allowing the skeleton to remain structurally sound throughout life. One way adaptation occurs in mammals is via Haversian remodeling: the site-specific, coupled resorption and formation of cortical bone that results in secondary osteons. Remodeling occurs at a baseline rate in most mammals, but it also occurs in relation to strain by repairing deleterious microdamage. Yet, not all animals with bony skeletons remodel. Among mammals, there is inconsistent or absent evidence for Haversian remodeling among monotremes, insectivores, chiropterans, cingulates, and rodents. Three possible explanations for this disparity are discussed: the capacity for Haversian remodeling, body size as a constraint, and age and lifespan as constraints. It is generally accepted, although not thoroughly documented, that rats (a common model used in bone research) do not typically exhibit Haversian remodeling. The present aim is to more specifically test the hypothesis that rats of advanced age do remodel intracortically because of the longer lifespan over which baseline remodeling could occur. Most published histological descriptions of rat bone only include young (3-6 months) rats. Excluding aged rats possibly overlooks a transition from modeling (i.e., bone growth) to Haversian remodeling as the primary mode of bone adaptation. Here, midshaft and distal femora (typical sites for remodeling in other mammals) of 24-month-old rats were examined for presence of secondary osteons. None were found, suggesting that Haversian remodeling does not occur in rats under normal physiological conditions at any age. A likely explanation is that modeling of cortical bone continues throughout most of the short rat lifespan, negating the stimulus for Haversian remodeling. Thorough sampling of key rodent taxa of varying body sizes and lifespans is key to elucidating the reasons why (i.e., body size, age/lifespan, phylogenetic factors) Haversian remodeling might not occur in all mammals.

Ecological Health Assessment of an Urban River: The Case Study of Zhengzhou City, China

Urban river ecological health assessment is an effective means to manage urban rivers, and combining principles of landscape ecology can provide new help for the ecological restoration of urban rivers and improving their ecosystem service value. From the perspective of important functions of ecosystems, based on typical sample site investigations of different river sections, questionnaire surveys, and remote sensing technology, a fuzzy comprehensive evaluation model based on the factor analysis method was used to construct an indicator system that can quantitatively reflect the ecological health of urban rivers. This comprehensive evaluation index system includes five major functions: social function, habitat and corridor function, water ecological function, water landscape function, and spatial enclosure function. The study identified key areas, key rivers, key river sections, and main indicator projects for the ecological restoration of the urban river landscape corridors in Zhengzhou. The study results also showed that the urban river landscape corridors in Zhengzhou have prominent problems in social function, water ecological function, and habitat and corridor function, and 62.1% of the river sections are currently in a sub-healthy state. The flood control function, eutrophication of water body, naturalization rate of revetment, and five other indicators in the old city district are significantly lower than those in the new city district, and the old city district should be the focus of the ecological restoration of urban river corridors. From the evaluation of the ecological health status of typical river sections, the Jinshui River and Xionger River have a larger number of river sections that urgently need restoration. This study provides a reference for the ecological restoration of urban rivers in Zhengzhou, a rapidly urbanizing region, and has reference significance for the construction of water landscapes in small and medium-sized cities with low levels of urbanization.

Coupled analysis of monopile offshore wind turbine under modified three-dimensional seafloor ground motions

The safe operation of offshore wind turbines (OWTs) is significantly influenced by the combined effect of wind, waves, and offshore earthquakes. However, limited seafloor ground motion data have been used to determine the dynamic characteristics and responses of OWTs subjected to offshore earthquakes. Hence, synthetic seafloor ground motions are particularly important for seismic analysis of OWTs. This paper proposes a new method to simulate seafloor ground motions. In the study, the dynamic shear modulus of the water-bearing soil layer and the damping effect of the soil–seawater layers were introduced to modify the simple Crouse and Quilter (C-Q) model in seawater and P-SV and SH transfer function models at offshore sites. Further, three-dimensional seismic waves were synthesized based on the modified transfer function models at a typical offshore site with bedrock–soil–seawater layers, and a fully coupled numerical analysis model of OWTs, including the rotor nacelle assembly, tower structure, and substructure with pile–soil interaction (PSI) under wind, wave, and seafloor ground motion, was established by incorporating the earthquake module and PSI module into the updated FAST v8 software. Moreover, based on the established coupled OWT model, the measured seafloor ground motion records and the seafloor ground motions synthesized using the proposed method were compared, and a coupled analysis of the OWT under wind, wave, and offshore earthquake loadings was carried out. Furthermore, the coupled mechanisms of the OWT under synthesized and recorded seafloor ground motions were determined.

Raising the Resilience of Industrial Manufacturers through Implementing Natural Gas-Fired Distributed Energy Resource Systems with Demand Response

The use of relatively small-scale distributed electric power generation sources is one of the key focus areas in the development of global industry and regional power generation. By integrating distributed generation sources into their on-site energy infrastructure, industrial consumers gain new characteristics and possibilities as entities of the power system that do not only consume power, but in fact can flexibly generate and deliver electricity to local and even centralized grids. This type of entity is called a distributed energy resource system with demand response (Russian: ‘active energy complex’). The purpose of this study is to lay the methodological foundation for the use of distributed energy resource systems with demand response in industrial sites under existing gas and power market conditions and for ensuring the synchronization of parameters that is necessary for managing complex energy consumption. This article provides an empirical study of the principles of the natural gas pricing under the demand volatility of regional markets and the Russian Mercantile Exchange. The article outlines the key drivers, as identified by the authors, that impact gas consumption by a distributed energy resource system, including demand characteristics, limitations and capacity of the gas network and the mode of gas consumption by an industrial enterprise and its generator. Accounting for all of these factors is essential for effective management and proper operational adjustment of a distributed energy resource system with demand response. The result of the study is a proprietary model and a tool for the management of distributed energy resource systems in integration with the gas demand management, which analyze the internal and external parameters of the industrial entity’s operations and its distributed energy resource system, as well as factors existing in the integrated distributed energy system where the consumer is able to buy natural gas in various market segments. The proprietary tool of distributed energy resource system management is based on the centralized control system, which combines performance analytics, operational scheduling of production and the distributed energy resource system, price planning for the wholesale and retail power markets, regional gas markets and exchange, monitoring all elements of the system, and assessment of different active energy management scenarios under various external and internal conditions impacting production and energy demand. Our proprietary tool has been successfully tested in a typical industrial site and was reported to deliver a significant electricity and gas cost-saving effect, which amounted to an 18 percent reduction in the total energy costs of the company, or more than USD 2.6 million per year. The resulting saving effect can recoup the costs of investing in a distributed energy resource system, including construction and installation of the local grid and automation infrastructure, and can be obtained in any country of the world.

Hydrogen-promoted in-void diffusion of helium in a 3C-SiC(310) twin boundary: a first-principles study

The role of H atoms in the formation of irradiation-induced He bubbles in SiC grain boundaries (GBs) is unclear. The effects of H on the formation energies (Ef s) and diffusion behaviour of He in the 3C-SiC twin boundary (TB) were studied using the density functional theory. We observed that a He atom stabilises at three typical sites in the 3C-SiC (310) TB with Ef s = 1.95, 2.05, and 1.67 eV, which are significantly lower than those in the SiC grains. The addition of the H atom shifts the stable sites of He in the TB and increases Ef s to 4.66, 3.96, and 5.13 eV. The minimum energy pathways for He diffusion in TB were changed by the addition of H atom. Moreover, the H atom reduces the barrier from 3.69 to 1.04 eV for the He diffusion in one TB void and increases it from 1.30 to 4.08 eV for the He diffusion between adjacent TB voids. We interpreted the above results through the Bader charge, density of states, and atomic force analysis. The results indicate that H promotes the in-void diffusion but suppresses the inter-void diffusion of He atoms in SiC GBs, which favours the aggregation and nucleation of He in SiC GBs.

Oral manifestations of COVID-19: A review

An important indicator of general health, well-being, and quality of life is oral health. The SARS-CoV-2 virus, which has been discovered to have a number of adverse effects. One of the earliest tissue areas to become infected by the virus and undergo alterations is the oral cavity. Oral manifestations included ulcer, erosion, bulla, vesicle, pustule, fissured or depapillated tongue, macule, papule, plaque, pigmentation, halitosis, white patches, haemorrhagic crust, necrosis, petechiae, swelling, erythema, and spontaneous bleeding. The tongue (38%), labial mucosa (26%), and palate (22%) were the three most typical sites of involvement. Aphthous stomatitis, herpetiform lesions, candidiasis, vasculitis, mucositis, drug eruption, necrotizing periodontal disease, angina bullosa-like, angular cheilitis, atypical sweet syndrome, and Melkerson-Rosenthal syndrome were suggested diagnoses for the lesions. In 68% of instances, oral lesions were symptomatic. There were almost equally as many oral lesions in both sexes (49% female and 51% male). More extensive and severe oral lesions were present in patients who were older and who had COVID-19 diseases that were more severe. The most significant risk factors for the development of oral lesions in COVID-19 patients include poor oral hygiene, opportunistic infections, stress, immunosuppression, vasculitis, and hyper-inflammatory response. It is crucial to identify any changes in the mucosa in COVID-19 patients and administer assertive treatment to prevent complications. Patients should also try to maintain adequate oral hygiene throughout the course of the illness to prevent the colonisation of opportunistic microorganisms and to prevent complications both orally and systemically.

Longitudinal seismic response of shield tunnel: A multi-scale numerical analysis

Developing a rational and efficient numerical model to analyze the longitudinal earthquake response of shield tunnel has become a hot topic in the field of underground structure seismic research in recent years. Based on the idea of scale coupling, this study proposed a multi-scale numerical model that can capture the dynamic response of ring joint in the vulnerable part of shield tunnel precisely. In this multi-scale model, the non-focused part of structure is described by the Timoshenko beam & nonlinear spring, while the focused part is described by the three-dimensional “refined ring joint”. The multi-scale model is subsequently utilized to calculate the longitudinal seismic response of the shield tunnel through a typical site with a soft-hard stratum junction. In addition, the influence of earthquake wave parameters on the seismic response of the tunnel structure is also discussed in this study. Some inspiring conclusions are as follows. The dynamic response of the shield tunnel rises dramatically near the soft-hard stratum interface because of the non-uniform deformation of the soil in that area. Strong earthquake waves (with high PGA or PGV) may cause nonlinear increase in the opening deformation of a ring joint and the yielding of several joint bolts. Under high intensity seismic load, the service state of joint bolts varies widely, and the damage is concentrated in one region of the ring joint.

The Spatial Distribution and Potential Risk Assessment of POPs in Farmland around a Typical E-Waste Dismantling Site.

Pollution from electronic-waste (E-waste) dismantling is of great concern. This study investigated the concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs) in 253 cropland soil samples around an abandoned E-waste dismantling site in Taizhou city, Zhejiang province in China, using an analytical method which simultaneously extracted, purified and determined the identity and quantity of the three types of persistent organic pollutants. Meanwhile, their spatial distributions, pollution characteristics, and risk assessments were further analyzed. Total PCBs in the test soils ranged from below method detection limits (ND) to 2985.25μgkg-1 on a dry weight basis (d.w.), and the spatial distribution indicated a "hot spot" of PCBs pollution in the study area. The PAHs were detected in all samples with total concentrations ranging from 4.99 to 2723.06μgkg-1d.w. The distribution of PBDEs showed the pollution characteristics of "family-run workshops", with a total content range of ND ~ 899.34μgkg-1d.w., of which BDE209 was typically the dominant congener, accounting for 74.05% of the total PBDEs content in the test soils, with the highest content reaching 857.72μgkg-1d.w. Results showed that the ecological and lifetime carcinogenic risks of PCBs and PAHs were low in the study area, but the health risk caused by oral ingestion and dermal contact accounted for the highest proportion of the total exposure risks, while inhalation could be ignored. PBDEs in soils of the study area were a potential chronic non-carcinogenic risk, particularly for children. Therefore, in order to protect human health and environment, it is necessary to regulate the management of E-waste dismantling sites and pollution control.

Main Emission Sources and Health Risks of Polycyclic Aromatic Hydrocarbons and Nitro-Polycyclic Aromatic Hydrocarbons at Three Typical Sites in Hanoi

Particulate matter-bound polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs (NPAHs) were first systematically studied in downtown (XT), suburban (GL) and rural (DA) sites in winter and summer in Hanoi, Vietnam, from 2019 to 2022. The mean concentrations of PAHs and NPAHs ranged from 0.76 ng m−3 to 50.2 ng m−3 and 6.07 pg m−3 to 1.95 ng m−3, respectively. The concentrations of PAHs and NPAHs in winter were higher than in summer, except for NPAHs in XT. We found the benzo[a]pyrene (BaP)/benzo[ghi]perylene (BgPe) ratio could effectively identify biomass burning in this study, in which a higher [BaP]/[BgPe] value indicates a greater effect of biomass burning on PAHs and NPAHs. The results indicated that atmospheric PAHs and NPAHs were mainly affected by motor vehicles (especially the unique motorcycles in Southeast Asia) in the summer in Hanoi. In winter, all sites were affected by the burning of rice straw to varying degrees, especially DA. The incremental lifetime cancer risk (ILCR) in Hanoi was first determined through ingestion, inhalation and dermal absorption. The results showed that residents in Hanoi faced high health risks, while females experienced higher health risks than males. The ingestion and dermal pathways indicated higher exposure risks than the usually considered inhalation pathway.

Assessing the viability of CO[formula omitted] storage in offshore formations of the Gulf of Mexico at a scale relevant for climate-change mitigation

We investigate the feasibility of industrial-scale geological carbon sequestration as an effective climate change mitigation technology. We do so by performing numerical simulations of coupled multiphase flow and geomechanics on a representative field-scale geological model in the Gulf of Mexico that could become a typical CO2 storage site. We use our representative model to investigate two potential hazards associated with large-scale CO2 storage: (1) The potential that CO2 might migrate to shallower formations and (2) The potential that CO2 injection might induce seismicity due to destabilization of pre-existing faults. At our study location, we find that extensive distribution of clay minerals in fault zones in combination with large fault throws result in widespread occurrence of low-permeability faults that prevent migration of CO2 outside of the injection interval. Low-permeability faults act as flow barriers and can result in reservoir compartmentalization and pore pressure build-up. For our field-scale geological model, we find that the risk of induced seismicity is controlled by the choice of the injection location with respect to pre-existing low-permeability faults. Our model results indicate that industrial-scale CO2 storage in the Gulf of Mexico is feasible, but that a priori reservoir characterization and the choice of injection location are crucial to mitigate the potential occurrence of induced seismicity and CO2 migration to shallower formations.