Exploring the diversity of dissolved organic matter (DOM) properties and sources in different functional areas of a typical macrophyte - derived lake combined with optical spectroscopy and FT-ICR MS analysis.

Lake Baiyangdian is one of China's largest macrophyte - derived lakes, facing severe challenges related to water quality maintenance and eutrophication prevention. Dissolved organic matter (DOM) was a huge carbon pool and its abundance, property, and transformation played important roles in the biogeochemical cycle and energy flow in lake ecosystems. In this study, Lake Baiyangdian was divided into four distinct areas: Unartificial Area (UA), Village Area (VA), Tourism Area (TA), and Breeding Area (BA). We examined the diversity of DOM properties and sources across these functional areas. Our findings reveal that DOM in this lake is predominantly composed of protein - like substances, as determined by excitation - emission matrix and parallel factor analysis (EEM - PARAFAC). Notably, the exogenous tyrosine-like component C1 showed a stronger presence in VA and BA compared to UA and TA. Ultrahigh - resolution mass spectrometry (FT - ICR MS) unveiled a similar DOM molecular composition pattern across different functional areas due to the high relative abundances of lignan compounds, suggesting that macrophytes significantly influence the material structure of DOM. DOM properties exhibited specific associations with water quality indicators in various functional areas, as indicated by the Mantel test. The connections between DOM properties and NO3N and NH3N were more pronounced in VA and BA than in UA and TA. Our results underscore the viability of using DOM as an indicator for more precise and scientific water quality management.

Development of a coupled model to simulate and assess arsenic contamination and impact factors in the Jinsha River Basin, China.

With the increasing severity of arsenic (As) pollution, quantifying the environmental behavior of pollutant based on numerical model has become an important approach to determine the potential impacts and finalize the precise control strategies. Taking the industrial-intensive Jinsha River Basin as typical area, a two-dimensional hydrodynamic water quality model coupled with Soil and Water Assessment Tool (SWAT) model was developed to accurately simulate the watershed-scale distribution and transport of As in the terrestrial and aquatic environment at high spatial and temporal resolution. The effects of hydro-climate change, hydropower station construction and non-point source emissions on As were quantified based on the coupled model. The result indicated that higher As concentration areas mainly centralized in urban districts and concentration slowly decreased from upstream to downstream. Due to the enhanced rainfall, the As concentration was significantly higher during the rainy season than the dry season. Hydro-climate change and the construction of hydropower station not only affected the dissolved As concentration, but also affected the adsorption and desorption of As in sediment. Furthermore, As concentration increased with the input of non-point source pollution, with the maximum increase about 30%, resulting that non-point sources contributed important pollutant impacts to waterways. The coupled model used in pollutant behavior analysis is general with high potential application to predict and mitigate water pollution.

Abiotic aerobic oxidation pathways of stibnite revealed by oxygen and sulfur isotope systematics of sulfate.

The environmental threat posed by stibnite is an important geoenvironmental issue of current concern. To better understand stibnite oxidation pathways, aerobic abiotic batch experiments were conducted in aqueous solution with varying δ18OH2O value at initial neutral pH for different lengths of time (15-300 days). The sulfate oxygen and sulfur isotope compositions as well as concentrations of sulfur and antimony species were determined. The sulfur isotope fractionation factor (Δ34SSO4-stibnite) values decreased from 0.8‰ to -2.1‰ during the first 90 days, and increased to 2.6‰ at the 180 days, indicating the dominated intermediate sulfur species such as S2O32-, S0, and H2S (g) involved in Sb2S3 oxidation processes. The incorporation of O into sulfate derived from O2 (∼100%) indicated that the dissociated O2 was only directly adsorbed on the stibnite-S sites in the initial stage (0-90 days). The proportion of O incorporation into sulfate from water (27%-52%) increased in the late stage (90-300 days), which suggested the oxidation mechanism changed to hydroxyl attack on stibnite-S sites promoted by nearby adsorbed O2 on stibnite-Sb sites. The exchange of oxygen between sulfite and water may also contributed to the increase of water derived O into SO42-. The new insight of stibnite oxidation pathway contributes to the understanding of sulfide oxidation mechanism and helps to interpret field data.

Perspectives on label-free microscopy of heterogeneous and dynamic biological systems.

Significance: Advancements in label-free microscopy could provide real-time, non-invasive imaging with unique sources of contrast and automated standardized analysis to characterize heterogeneous and dynamic biological processes. These tools would overcome challenges with widely used methods that are destructive (e.g., histology, flow cytometry) or lack cellular resolution (e.g., plate-based assays, whole animal bioluminescence imaging). Aim: This perspective aims to (1) justify the need for label-free microscopy to track heterogeneous cellular functions over time and space within unperturbed systems and (2) recommend improvements regarding instrumentation, image analysis, and image interpretation to address these needs. Approach: Three key research areas (cancer research, autoimmune disease, and tissue and cell engineering) are considered to support the need for label-free microscopy to characterize heterogeneity and dynamics within biological systems. Based on the strengths (e.g., multiple sources of molecular contrast, non-invasive monitoring) and weaknesses (e.g., imaging depth, image interpretation) of several label-free microscopy modalities, improvements for future imaging systems are recommended. Conclusion: Improvements in instrumentation including strategies that increase resolution and imaging speed, standardization and centralization of image analysis tools, and robust data validation and interpretation will expand the applications of label-free microscopy to study heterogeneous and dynamic biological systems.

Contributions of fossil and non-fossil fractions to total carbon in urban aerosols in Bratislava (Slovakia).

Radiocarbon measurements of total carbon (TC) fraction of aerosol samples collected at the campus of the Comenius University in Bratislava (Slovakia) during 2022-2023 were carried out. Based on radiocarbon activity of these samples and a source apportionment model we have determined the relative proportion of fossil and non-fossil carbon in collected atmospheric aerosols. The carbon from non-fossil sources (biomass burning and biogenic emissions) was dominant in this time period, on average it formed 72% of carbon present in the aerosols from the atmosphere of Bratislava. The whole range of determined non-fossil fraction was relatively small as it varied only from 0.67 (August-September) to 0.82 (December-January). These changes do not exhibit any significant seasonal variation as was previously observed in Bratislava during 2017-2018 in the elemental carbon (EC) aerosol fraction.

Efficacy of powered air purifying respirators (PAPRs) for source control of simulated respiratory aerosols.

BACKGROUND: Loose-fitting powered air purifying respirators (PAPRs) are a popular alternative to the use of filtering facepiece respirators for healthcare workers. Although PAPRs protect the wearer from aerosol particles, their ability to block infectious aerosol particles exhaled by the wearer from being released into the environment (called source control) is unclear. METHODS: The source control performance of four PAPRs with loose-fitting facepieces were tested using a manikin that exhales aerosol particles. The PAPRs were tested by themselves and in combination with a face-worn product intended to provide source control (either a surgical mask or an N95® filtering facepiece respirator.) RESULTS: Two PAPR facepieces with filtration panels significantly reduced the release of exhaled aerosols into the environment, while three facepieces without such panels did not. Wearing a surgical mask or respirator under the facepiece significantly improved the source control performance. CONCLUSIONS: Most PAPR facepieces do not block aerosols exhaled by the wearer. Facepieces designed to filter exhaled particles can prevent aerosols from being released into the environment. Wearing a surgical mask or a filtering facepiece respirator under the facepiece can also provide source control, but PAPRs are not typically certified for use with masks and respirators.

Protein adequacy, plant protein proportion and main plant protein sources consumed across vegan, vegetarian, pesco-vegetarian and semi-vegetarian diets: A systematic review.

BACKGROUND: There are several types of plant-based diets, with unknown differences across diets on total/plant protein intake and variety of plant protein sources consumed. OBJECTIVE: This systematic review compares total protein intake, proportion of plant proteins and main plant-protein sources consumed across four primarily plant-based diets: vegan, vegetarian, pesco-vegetarian and semi-vegetarian. METHODS: We included observational studies reporting on protein intake and/or protein sources in generally healthy adults that were published between 2002 and 2023. We determined (i) % energy from total and plant protein, (ii) the proportion of plant protein relative to total protein intake and (iii) main plant protein sources (median % contribution of each source to total plant protein intake; interquartile range) consumed across the four diets. The plant protein sources were broadly classified into United States Department of Agriculture (USDA) food-groups: "grains", "nuts and seeds", "soy-products" and "beans, peas, lentils". RESULTS: We included 13 studies reporting on protein intake/sources that were conducted in the US, Europe, and South Korea. Of these, 7 reported on vegan, 11 on vegetarian, 7 on pesco-vegetarian and 7 on semi-vegetarian diets with total protein intake ranging from 10-17.4%. Vegan diets had the highest plant protein proportion (ranging from 77-98%) and semi-vegetarian diets the lowest (ranging from 37-83%). Plant protein source contribution was highest from grains (ranging from 60-78%). Nuts and seeds were most consumed in vegetarian diets (7.9%;2.9-10.3%) and least in semi-vegetarian diets (3.7%;2-14.8%). Soy products, beans, peas, and lentils were most consumed in vegan diets (17.3%;16.3-19.9 and 19.6%;14.6-21.3, respectively) and least in semi-vegetarian (3.7%;1.3-13.9 and 8.5%;5.2-10.2) diets. CONCLUSIONS: Vegan diets had the highest plant protein proportion and a variety of plant protein sources, while semi-vegetarian diets had the lowest plant protein proportion and mainly relied on grains as a plant protein source.

Investigating the impact of climate variables on the organic honey yield in Turkey using XGBoost machine learning.

BACKGROUND: The Turkish organic honey industry, a major player in the global market, faces challenges due to climate fluctuations. Understanding the influence of climate factors on honey production is vital for sustainable farming and economic stability. METHOD: This study uses a machine learning approach with the XGBoost algorithm to analyze temperature, wind, humidity, precipitation and surface pressure over a 20-year period from 2004 to 2023. RESULTS: The results show that these factors significantly impact organic honey production, with temperature, wind, humidity, precipitation and surface pressure having effects of 41.20%, 26.50%, 12.47%, 11.42% and 8.41%, respectively. Sensitivity analysis reveals the model's sensitivity to even minor fluctuations in these variables. CONCLUSION: The results of this research underscore the necessity of integrating climate change mitigation and adaptation measures into agricultural policies and beekeeping practices. This study showcases the practical application of machine learning in deciphering the intricate relationship between climate change and the production of crops, emphasizing the importance of data-driven decision-making to guarantee long-term sustainability and financial stability in the sector. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of artificial sugar supplement on the lifespan and learning memory ability of honey bee (Apis cerana) worker bee offspring.

Honeybees maintain their growth and reproduction mainly by collecting nutrients from nectar-source plants. Apis cerana, a unique species of honeybee in China, is capable of sporadically collecting nectar. In traditional beekeeping, sugar syrup or a honey-water solution must be artificially fed to bees to supplement their diet during rainy weather or nectar-deficient periods. In this study, 2 groups of honeybee colonies were each fed sugar syrup or a honey-water solution, and a third group consisting of colonies that were allowed to naturally forage without any dietary supplement was used as the control. The effects of the 2 sugar sources on A. cerana worker bee offspring were compared. The results showed that the sugar source affected the lifespan and learning memory of the worker bee offspring. The lifespan, learning memory ability, and expression of related genes in the sugar syrup group were significantly lower than those in the honey-water solution and natural nectar foraging groups (P < 0.05). A honey-water solution supplement was more beneficial to the healthy development of worker bee offspring than a sugar syrup supplement when the colonies lacked dietary resources. These findings provide a theoretical basis that can guide beekeepers in choosing the appropriate dietary supplements for honeybees.

Sweet Immunity in Action: Unlocking Stem Reserves to Improve Yield and Quality. A Potential Key Role for Jasmonic Acid.

Common agronomic practices such as stem topping, side branch removal, and girdling can induce wound priming, mediated by jasmonic acid (JA). Low light conditions during greenhouse tomato production make the leaves more sensitive to the application of exogenous sugar, which is perceived as a "danger" in accordance with the concept of "Sweet Immunity". Consequently, source-sink balances are altered, leading to the remobilization of stem starch reserves and enabling the redirection of more carbon toward developing fruits, thereby increasing tomato yield and fruit quality. Similarities are drawn with the mobilization of fructans following defoliation of fodder grasses (wounding) and the remobilization of fructan and starch reserves under terminal drought and heat stress in wheat and rice (microwounding, cellular leakage). A central role for JA signaling is evident in all of these processes, closely intertwining with sugar signaling pathways. Therefore, JA signaling, associated with wounding and sugar priming events, offers numerous opportunities to alter source-sink balances across a broader spectrum of agricultural and horticultural crops, for instance, through the exogenous application of JA and fructans or a combination. This may entail reconfiguring and reversing phloem connections, potentially leading to an enhanced yield and product quality. Such processes may also disengage the growth-defense trade-off in plants.

Spatio-temporal characteristics and multi-scale risk identification of pollution load based on sensitivity analysis in small watersheds located in Tuojiang River Basin, China.

High-quality development of water resources supports high-quality socio-economic development. High-quality development connects high-quality life, and clarifying the key management contents of small watersheds plays an important role in building ecologically clean small watersheds and promoting regional production and life. Previous research on pollution loads has focused on examining the impact of various external drivers on pollution loads but still lacks research on the impact of changes in pollution sources themselves on pollution loads. In this study, sensitivity analysis was used to determine the impact of changes from different sources on the total pollution loads, which can recognize the critical pollution sources. We first employed the pollutant discharge coefficient method to quantify non-point source pollution loads in the small watershed in the upstream Tuojiang River basin from 2010 to 2021. Then, combination sensitivity analysis with Getis-Ord Gi* was used to identify the critical sources and their crucial areas at the global, districts (counties), and towns (streets) scales, respectively. The results indicate: (1) The pollution loads of COD, NH3-N, TN, and TP all show a decreasing trend, reducing by 18.3%, 16.2%, 18.6%, and 28.1% from 2010 to 2021, respectively; (2) Livestock and poultry breeding pollution source is the most critical source for majority areas across watershed; (3) High-risk areas are mainly concentrated in Jingyang district and its subordinate towns (streets). There is a trend of low-pollution risk areas transitioning to high-pollution risk areas, with high-risk areas predominantly concentrated in the southeast and exhibiting a noticeable phenomenon of pollution load spilling around. This study can promote other similar small watersheds, holding significant importance for non-point source pollution control in small watersheds.

Polycyclic aromatic hydrocarbons (PAHs) in blood serum of adults living in high and low-traffic volume areas in Malaysia: A comparative cross-sectional study.

Ambient polycyclic aromatic hydrocarbons (PAHs) originate predominantly from fuel combustion of motor vehicles and have the potential to affect human health. However, there is insufficient knowledge regarding serum PAHs health risks among the Malaysian population. This study aims to compare PAH concentrations, distributions, correlations, and health risks in 202 blood serum samples drawn from residents living in high-traffic volume areas (Kuala Lumpur) and low-traffic volume areas (Hulu Langat) in Malaysia. Solid phase extraction and gas chromatography-mass spectrometry (GC-MS) were employed to extract and analyze blood serum samples. Questionnaires were distributed to obtain sociodemographic and contributing factors of serum PAHs. The mean total PAHs concentration in serum of the Kuala Lumpur group was 54.44 ng g-1 lipids, double the Hulu Langat group's concentration (25.7 ng g-1 lipids). Indeno(1,2,3-cd)pyrene (IcP) and acenaphthene (ACP) feature the most and least abundant compounds in both study groups. The mean concentrations of IcP and ACP in the Kuala Lumpur and Hulu Langat groups were 26.8 vs 12.68 and 0.27 vs 0.14 ng g-1 lipids, respectively. High-molecular-weight PAHs (HMW-PAHs) composed 85% of serum total PAHs in both groups. Significant correlations were found (i) between the individual serum PAH congeners (p < 0.01) and (ii) between serum PAHs and total lipids (p < 0.01). According to the questionnaire data, high traffic volume and outdoor hobbies were the only contributory factors that confirmed significant relationships with serum PAHs (p < 0.001). Health risk assessment was computed using benzo(a)pyrene (BaP) equivalent (BaPeq) and demonstrated that the Kuala Lumpur group has twofold greater carcinogenic risk than the Hulu Langat group (16.11 vs 7.76 ng g-1 lipids). Our study reveals that traffic volumes notably impact serum PAH levels and general health among the Malaysian population.

Influence of grain type and fat source on performance, nutrient utilization, and gut properties in broilers fed pelleted diets.

The influence of grain type and fat source on the performance, coefficient of apparent ileal digestibility (CAID), and intestinal characteristics in broiler starters fed pelleted diets were studied. The experiment included 8 treatments arranged as a 2 × 4 factorial with 2 grains (wheat and corn) and 4 fat sources (soybean oil, fish oil, tallow, and palm oil). In all fat sources, corn-fed birds had a higher weight gain than those fed wheat-based diets. However, improvement in the weight gain of birds fed wheat-based diets supplemented with tallow resulted in a significant (P < 0.001) interaction between grain type and fat source. Inclusion of wheat and tallow increased feed intake compared to corn and other fat sources, respectively. Pellets made from wheat were harder (P < 0.01) than those based on corn. Broilers fed corn-based diets, had higher CAID of fat, Ca, and phosphorus (P < 0.01) than those fed wheat-based diets. Soybean oil inclusion, also increased (P < 0.01) fat digestibility compared to other fat sources. An interaction occurred between grain type and fat source where pellets made from corn and soybean oil had higher protein digestibility compared to the other treatments (P < 0.01). Feeding wheat-based diets increased pH of gizzard and proventriculus compared to corn-based diets (P < 0.01). Highest viscosity value was observed in wheat-diets supplemented with fish oil, and palm oil (P < 0.01). The pancrease, gizzard and cecum were heavier in corn-based fed birds compared to those fed wheat-based diets (P < 0.01). A significant interaction between grain type and fat source was noted for Lactobacillus spp. and the total anaerobic bacteria population in the cecum. Overall, the effect of grain type on weight gain, CIAD of protein and cecal microbiota differed depending on the fat sources. Feeding corn and soybean oil resulted in better gut development and growth performance in broilers fed pelleted diets.

Nova-ST: Nano-patterned ultra-dense platform for spatial transcriptomics.

Spatial transcriptomics workflows using barcoded capture arrays are commonly used for resolving gene expression in tissues. However, existing techniques are either limited by capture array density or are cost prohibitive for large-scale atlasing. We present Nova-ST, a dense nano-patterned spatial transcriptomics technique derived from randomly barcoded Illumina sequencing flow cells. Nova-ST enables customized, low-cost, flexible, and high-resolution spatial profiling of large tissue sections. Benchmarking on mouse brain sections demonstrates significantly higher sensitivity compared to existing methods at a reduced cost.

Open-source hardware and software for the measurement, characterization, reporting, and correction of geometric distortion in MRI.

BACKGROUND: Geometric distortion is a serious problem in MRI, particularly in MRI guided therapy. A lack of affordable and adaptable tools in this area limits research progress and harmonized quality assurance. PURPOSE: To develop and test a suite of open-source hardware and software tools for the measurement, characterization, reporting, and correction of geometric distortion in MRI. METHODS: An open-source python library was developed, comprising modules for parametric phantom design, data processing, spherical harmonics, distortion correction, and interactive reporting. The code was used to design and manufacture a distortion phantom consisting of 618 oil filled markers covering a sphere of radius 150 mm. This phantom was imaged on a CT scanner and a novel split-bore 1.0 T MRI magnet. The CT images provide distortion-free dataset. These data were used to test all modules of the open-source software. RESULTS: All markers were successfully extracted from all images. The distorted MRI markers were mapped to undistorted CT data using an iterative search approach. Spherical harmonics reconstructed the fitted gradient data to 1.0 ± 0.6% of the input data. High resolution data were reconstructed via spherical harmonics and used to generate an interactive report. Finally, distortion correction on an independent data set reduced distortion inside the DSV from 5.5 ± 3.1 to 1.6 ± 0.8 mm. CONCLUSION: Open-source hardware and software for the measurement, characterization, reporting, and correction of geometric distortion in MRI have been developed. The utility of these tools has been demonstrated via their application on a novel 1.0 T split bore magnet.

The use of sedimentary metals to assess anthropogenic change, ecological risk, model past and future impacts and identify contaminant sources in the eleven estuaries of Greater Sydney (Australia): A review and critical assessment.

The Greater Sydney (Australia) region is dissected by eleven major estuaries comprising a wide range of sizes, sediment and contaminant types, while the catchments also vary in size, land use type, populations size and geology/soils. The magnitude and breadth of the current study are rare and offered an unusual opportunity to provide new information on interactions between source, fate and effect relationships of a highly diverse estuarine-catchment environment using sedimentary metals (Co, Cr, Cu, Ni, Pb and Zn). Advanced methodologies used in this study revealed that although metal concentrations were generally high, ecological risk was surprisingly reduced due to the presence of metal-poor coarse sediment. Stormwater was identified as the dominant source of metals to estuaries of Greater Sydney and relates to development of high-density road networks. Industrial sources, frequently identified as a major contributor to estuarine contamination, was significantly reduced due to the decline of industry through decentralisation and gentrification and because waste is discharged to the sewer system, which is released offshore, or tertiary-treated to the Hawkesbury. Groundwater leachate associated with shoreline reclamation and wetland infilling and metals related to boating activities were important sources of metals impacting local bays and coastal lagoons. Temporal monitoring and unique modelling approaches indicated that the concentration of sedimentary metals is generally declining in these estuaries, (especially for Pb), except for areas with rapidly increasing urban populations. Multivariate statistical modelling was able to differentiate the 11 estuaries on a chemical basis by aligning Cu, Pb, Zn vectors with metal-rich estuaries and also identified catchment attributes (percent area, total yield, anthropogenic yield and population density) normalised to catchment areas as having a major influence on estuarine condition. The new knowledge derived from this study should be used to assess the environmental status of estuaries and to prioritise management actions in future investigations.

Evaluating three-dimensional lung reconstructions for thoracoscopic lung resections using open-source software: a pilot study.

Background: Preoperative three-dimensional (3D) lung reconstructions can reduce intraoperative blood loss, conversion rate, and operation duration. These 3D reconstructions are predominantly provided by commercial expensive products, hence we aimed to assess the usability and performance of preoperative 3D lung reconstructions created with open-source software. Methods: Patients were invited to participate in this prospective pilot study if they were planned for uniportal video-assisted thoracoscopic surgery (VATS) lobectomy or segmentectomy between January and February 2023. Participants were excluded if a two-dimensional (2D) late-arterial-phase computed tomography (CT) scan contained motion artifacts, another surgical procedure was performed, or the surgery was canceled. After informed consent was obtained, 3D lung reconstructions were constructed using open-source 3D Slicer software. The system usability score (SUS) questionnaire assessed the usability of these reconstructions, whilst performance was evaluated based on anatomical validity compared to prior 2D CT assessment as well as operative findings. Descriptive statistics were reported. Results: Thirteen patients were included, of whom one underwent a segmentectomy. Eighty-three percent of the 3D lung reconstructions scored above average (SUS >68). Compared to 2D CT scans, 38% of lung nodule segmental locations were detected more accurately through 3D lung reconstructions. Furthermore, 3D lung reconstructions revealed anatomical variations in 62%, which were not recognized on 2D CT scans, and provided surgeons with insights that would change the procedure and/or transection planes in 62%. One 3D lung reconstruction failed to demonstrate an intraoperative recognized segmental pulmonary artery (A6) branch. Conclusions: Three-dimensional lung reconstructions created with open-source software were usable and effective for uniportal VATS anatomical resections. Trial Registration: ClinicalTrials.gov/NCT06132607.

Deciphering the pollution risks, sources and their links of heavy metals in soils.

Heavy metals in soils pose serious ecological and health risks. To make efficient strategies for mitigating the underlying hazards, it is critical to reveal the pollution sources and their links with the risks. Researchers have investigated source identification and risk evaluation of heavy metals in soils, yet few have systematically deciphered the source-sink relationship of soil metals and the links between source apportionment and risk assessment. In the study, an integrated technological framework has been proposed to address the gaps, and applied to characterize the pollution risks, sources and their links of soil metals in a typical coal resource city in China. The assessment using geochemical tool and ecological risk index shows the soils in study area are polluted by Cd, Hg, Cr, As and Pb in varied degrees, and particularly, Cd and Hg present significant ecological risk. Two advanced receptor models (multivariate curve resolution-weighted alternating least-squares and multilinear engine 2) are comparatively applied for apportioning the potential sources of soil metals, and the results suggest the two models have identified similar sources (r2 > 0.90), including agricultural activities, atmospheric depositions and industrial discharges with contributions of 35.5 %-38.3 %, 30.3 %-35.1 %, and 26.6 %-34.1 %, respectively. Then, apportionment results of the two models are jointly employed for evaluating the source-specific health risks of metals in the environment using a probabilistic risk assessment model. The risk levels within the area are overall acceptable or tolerable, and relatively, the industrial discharges present higher contribution on the non-carcinogenic and carcinogenic risks of soil metals to public. Findings will help the managers to design targeted policies for reducing the risks of soil metals, and the framework proposed provides a useful guideline to better understand the source-risk relationship of soil metals in other environments worldwide.

Quantum Prism-Nano Source of Light with Dispersive Spectrum and Optical Upconversion.

A quantum prism, a new structure, consisting of many quantum wires with a diameter that gradually decreases from the base to the top, is the focus of our research. This distribution of quantum wires leads to a dispersive emitted spectrum. The red edge of the spectrum is determined by the band gap width of the bulk semiconductor, and the blue edge is determined by the quantum size of the excitons at the top of the prism. The PL spectrum of the silicon prismatic sample was excited by weak and strong light absorption. At weak absorption (hνex = 1.2 eV), the PL spectrum is located in the visible part of the spectrum, from 1.4 eV to 1.9 eV, with an energy higher than the band gap of the Si crystal. Such a "blue shift" of PL spectra by 0.7 eV is characteristic of the quantum confinement effect. It is a rainbow spectrum with an optical upconversion. The quantum prism is a new type of nano light source, as it replaces two elements in a conventional spectrometer: a light source and a dispersive element. These features enable to create a nano-spectrometer for measuring the absorption spectrum of individual molecules or viruses.

Improvement of model simulation for summer PM2.5 and O3 through coupling with two new potential HONO sources in the North China Plain.

A large fraction of fine particulate matter (PM2.5) and ozone (O3) in the troposphere originates from secondary formation through photochemical processes, which remarkably contributes to the deterioration of regional air quality in China. The photochemical reactions initiated by hydroxyl radicals (OH) play vital roles in secondary PM2.5 and O3 formation. In contrast, the OH levels in polluted areas are underestimated by current chemical transport models (CTMs) because of the strongly unknown daytime sources of tropospheric nitric acid (HONO), which has been recognized as the dominant source of primary OH in polluted areas of China. In this study, the atmospheric HONO levels at two urban sites were found to be significantly underestimated by the WRF-Chem model based on available information on HONO sources. The HONO levels could be well reproduced by the WRF-Chem model after incorporating two new potential HONO sources from the photochemical reactions of NOx, as proposed in our previous study based on chamber experiment results. Comparing the simulations with available information of HONO sources, the simulated levels of atmospheric OH, secondary inorganic and organic aerosols (SIA and SOA), PM2.5 and daily maximum 8-h average (MDA8) O3 were evidently elevated or were closer to the observations over the North China Plain (NCP), with elevation percentages of 0.48-20.1 %, and a decrement percentage of -5.79 % for pNO3-. Additionally, the compensating errors in modeling PM2.5 and the gap in MDA8 O3 levels between observation and simulation in 2 + 26 cities became evidently smaller. The results of this study indicated that the empirical parameterization of two new potential HONO sources through photochemical reactions of NOx improved the model performance in modeling PM2.5 and O3 by narrowing the gap in daytime HONO levels between simulation and observation, although their detailed chemical mechanisms are still unknown and should be further investigated and explicitly parameterized.