Analysis Of Spatial Distribution Research Articles

Absorption and translocation of selected pharmaceuticals in Pistia stratiotes: Spatial distribution analysis using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Phytoremediation can eliminate pharmaceuticals from aquatic environments through absorption; however, understanding of absorption and transport processes in plants remains limited. In this study, a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry imaging (MALDI-MSI) method was developed to explore the absorption and translocation mechanisms of seven common pharmaceuticals in Pistia stratiotes. Results showed that 2,3-dicyanohydroquinone, an infrequently used matrix, exhibited outstanding performance in MALDI-MSI analysis, producing the highest signal intensity for four of the seven pharmaceuticals. Region of Interest (ROI) analysis revealed that charge speciation of pharmaceuticals significantly influenced their ability to enter vascular bundle. Neutral and positively charged pharmaceuticals easily entered vascular bundle, while negatively charged pharmaceuticals faced difficulty. ROI results for neutral and negatively charged pharmaceuticals exhibited positive correlation with their transfer factor values, indicating that their translocation ability from root to shoot was related to their capacity to enter vascular bundle. However, no correlation was observed for positively charged pharmaceuticals, suggesting that these compounds, upon entering vascular bundle, encountered difficulties in upward translocation through the xylem. This study introduces an innovative approach and offers novel insights into the retention and migration of pharmaceuticals in plant tissues, aiming to enhance the understanding of pharmaceutical accumulation in plants. Environmental implicationPharmaceuticals in aquatic environment can inflict detrimental effects on both human health and ecosystem. Phytoremediation can remove pharmaceuticals from aquatic environments through absorption. However, our understanding of absorption and transportation of pharmaceuticals in plants remains limited. This study developed a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry imaging (MALDI-MSI) method for pharmaceuticals in plant roots, and to explore the absorption and translocation mechanisms of pharmaceuticals. The study offers direct evidence of differences in accumulation behavior of pharmaceuticals in plants, providing valuable insights for targeted and effective strategies in using plants for remediating the aquatic ecosystem from pharmaceuticals.

Three‐dimensional Modeling of Ore‐forming Elements and Mineralization Prognosis for the Yechangping Mo Deposit, Henan Province, China

AbstractThree‐dimensional geochemical modeling of ore‐forming elements is crucial for predicting deep mineralization. This approach provides key information for the quantitative prediction of deep mineral localization, three‐dimensional fine interpolation, analysis of spatial distribution patterns, and extraction of quantitative mineral‐seeking markers. The Yechangping molybdenum (Mo) deposit is a significant and extensive porphyry‐skarn deposit in the East Qinling–Dabie Mo polymetallic metallogenic belt at the southern margin of the North China Block. Abundant borehole data on ore‐forming elements underpin deep geochemical predictions. The methodology includes the following steps: (1) Three‐dimensional geological modeling of the deposit was established. (2) Correlation, cluster, and factor analyses post delineation of mineralization stages and determination of mineral generation sequence to identify (Cu, Pb, Zn, Ag) and (Mo, W, mfe) assemblages. (3) A three‐dimensional geochemical block model was constructed for Mo, W, mfe, Cu, Zn, Pb, and Ag using the ordinary kriging method, and the variational function was developed. (4) Spatial distribution and enrichment characteristics analysis of ore‐forming elements are performed to extract geological information, employing the variogram and w(Cu + Pb + Zn + Ag)/w(Mo + W) as predictive indicators. (5) Identifying the western, northwestern, and southwestern areas of the mine with limited mineralization potential, contrasted by the northeastern and southeastern areas favorable for mineral exploration.

Molecular mapping of neuronal architecture using STORM microscopy and new fluorescent probes for SMLM imaging.

Imaging neuronal architecture has been a recurrent challenge over the years, and the localization of synaptic proteins is a frequent challenge in neuroscience. To quantitatively detect and analyze the structure of synapses, we recently developed free SODA software to detect the association of pre and postsynaptic proteins. To fully take advantage of spatial distribution analysis in complex cells, such as neurons, we also selected some new dyes for plasma membrane labeling. Using Icy SODA plugin, we could detect and analyze synaptic association in both conventional and single molecule localization microscopy, giving access to a molecular map at the nanoscale level. To replace those molecular distributions within the neuronal three-dimensional (3D) shape, we used MemBright probes and 3D STORM analysis to decipher the entire 3D shape of various dendritic spine types at the single-molecule resolution level. We report here the example of synaptic proteins within neuronal mask, but these tools have a broader spectrum of interest since they can be used whatever the proteins or the cellular type. Altogether with SODA plugin, MemBright probes thus provide the perfect toolkit to decipher a nanometric molecular map of proteins within a 3D cellular context.

A Phase II Open-Label Randomized Clinical Trial of Preoperative Durvalumab or Durvalumab plus Tremelimumab in Resectable Head and Neck Squamous Cell Carcinoma.

Clinical implications of neoadjuvant immunotherapy in patients with locally advanced but resectable head and neck squamous cell carcinoma (HNSCC) remain largely unexplored. Patients with resectable HNSCC were randomized to receive a single dose of preoperative durvalumab (D) with or without tremelimumab (T) before resection, followed by postoperative (chemo)radiotherapy based on multidisciplinary discretion and 1-year D treatment. Artificial intelligence (AI)-powered spatial distribution analysis of tumor-infiltrating lymphocytes and high-dimensional profiling of circulating immune cells tracked dynamic intratumoral and systemic immune responses. Of the 48 patients enrolled (D, 24 patients; D+T, 24 patients), 45 underwent surgical resection per protocol (D, 21 patients; D+T, 24 patients). D±T had a favorable safety profile and did not delay surgery. Distant recurrence-free survival (DRFS) was significantly better in patients treated with D+T than in those treated with D monotherapy. AI-powered whole-slide image analysis demonstrated that D+T significantly reshaped the tumor microenvironment toward immune-inflamed phenotypes, in contrast with the D monotherapy or cytotoxic chemotherapy. High-dimensional profiling of circulating immune cells revealed a significant expansion of T-cell subsets characterized by proliferation and activation in response to D+T therapy, which was rare following D monotherapy. Importantly, expansion of specific clusters in CD8+ T cells and non-regulatory CD4+ T cells with activation and exhaustion programs was associated with prolonged DRFS in patients treated with D+T. Preoperative D±T is feasible and may benefit patients with resectable HNSCC. Distinct changes in the tumor microenvironment and circulating immune cells were induced by each treatment regimen, warranting further investigation.

Mapping wing morphs of Tetrix subulata using citizen science data: Flightless groundhoppers are more prevalent in grasslands near water

Abstract The slender groundhopper (Orthoptera: Tetrigidae) Tetrix subulata (Linnaeus, 1758), like several other taxa of winged insects, has a long‐winged and a short‐winged form, the latter incapable of flight. The optimal habitat of T. subulata consists of wet meadows and flat shores, as they feed mostly on algae and mosses in damp, sun‐exposed, open patches. Contrasting hypotheses predict either short‐ or long‐winged morphs to be relatively more prevalent in optimal habitats. Previous investigations were limited in their spatial extent. To strongly increase the number of study locations, we obtained, through the Global Biodiversity Information Facility (GBIF), geo‐referenced observations made by citizen scientists in the Netherlands. We determined individuals' wing form based on photographs accompanying these observations and related wing‐form patterns to large‐ and medium‐scale landscape characteristics. Our analyses revealed that in grasslands near the major rivers, relatively more short‐winged individuals were found. In drier landscapes consisting of coniferous forests and heath on the higher sand areas, more long‐winged individuals were observed. Built‐up areas had no significant effect on the wing length. These patterns might be caused by the oogenesis‐flight syndrome or small‐scale spatial sorting, but the exact mechanism is yet unknown, as size‐dependency might also play a role. Although opportunistic observations are biased by where and when observers prefer to go, and by reporting probabilities varying between species groups, these biases are not likely to have affected our conclusions. Citizen science data appear to be suitable for analyses of spatial distribution and sorting of morphological types within species.

Spatial distribution and migration pattern analysis of Erythroculter erythropterus utilizing a telemetry approach in relation to water quality in the Nakdong River basin

The fish Erythroculter erythropterus has been introduced to the Nakdong River. It is a top carnivore (growing to up to 1.5 m long) but is inedible. The population of Erythroculter erythropterus tends to increase in areas where mainstream flow is slowed by weirs, likely due to the creation of more favorable habitat conditions. Erythroculter erythropterus dominates the fish community, reducing the number of endemic and commercial fish. The South Korean government sought to eliminate the species, but the spread was too rapid, resulting in top-down biological disturbance. The species distributions and movement patterns of Erythroculter erythropterus are not well known and no management strategy is available. Here, we determined the distribution and migration patterns of Erythroculter erythropterus in the tributaries and mainstream of the Nakdong River and analyzed how the water chemistry and physical habitat affected these variables. We used a submersible ultrasonic receiver to collect signals from transmitters attached to fish and analyzed the migration pattern. Massive aggregations of this species were evident at depth. Erythroculter erythropterus dominated all study sites but was significantly (p < 0.05) more common in the mainstream (relative abundance [RA] = 12.2%) than in tributaries (RA = 1.45%). Water quality parameters significantly regulated the population; total organic carbon was the highest one (R2 = 0.71). The transmitters revealed massive congregations in the deepest water (− 17 m) during winter hibernation, which sheds light on how the fish can best be removed.

Distribution of regional state aid in Slovakia: A focus on the least developed districts

AbstractThis paper examines the geographical distribution of regional state aid in Slovakia between 2004 and 2021, while focusing on projects realized in the least developed districts. The purpose is to answer the following research question: how much investment support is provided to areas with high rates of long-term unemployment to promote local economic activity? The investigation was conducted using a spatial distribution analysis and descriptive statistical methods. The findings demonstrate that the level of support in less developed districts is below the level of aid directed into more developed regions not only in terms of the number of supported projects, but also regarding the total amount of aid and the number of created jobs. Out of the 20 least developed districts we monitored, only the results for Košice-okolie significantly outperformed the results of the other districts. This article provides possible explanations for these findings and contributes to the literature by providing insights into the practical application of state aid in Slovakia.

Comprehensive distribution characteristics and factors affecting the migration of chromium in a typical chromium slag-contaminated site with a long history in China.

The contamination of abandoned chromium slag-contaminated sites poses serious threats to human health and the environment. Therefore, improving the understanding of their distribution characteristics and health risks by multiple information is necessary. This study explored the distribution, accumulation characteristic, and the role in the migration process of chromium. The results showed that the contents of total Cr and Cr (VI) ranged from 12.00 to 7400.00mg/kg, and 0.25 to 2160.00mg/kg, respectively. The average contents of both total Cr and Cr (VI) reached the highest value at the depth of 7-9m, where the silt layer retaining total Cr and Cr (VI) was. The spatial distribution analysis revealed that the total contamination area percentages of total Cr and Cr (VI) reached 7.87% and 90.02% in the mixed fill layer, and reduced to 1.21% and 34.53% in the silty layer, and the same heavily polluted areas were located in the open chromiumresidue storage. Soil pH and moisture content were the major factors controlling the migration of total Cr and Cr(VI) in soils. Results of probabilistic health risk assessment revealed that carcinogenic risk was negligible for adults and children, and the sensitive analysis implied that the content of Cr(VI) was the predominant contributor to carcinogenic risk. The combination of chemical reduction and microbial remediation could be the feasible remediation strategy for soil Cr(VI) pollution. Overall, this study provides scientific information into the chromium post-remediation and pollution management for various similar chromium-contaminated sites.

Identification of sources and analysis of spatial distribution of soil heavy metals in northern China coal mining areas.

The mining and utilization of coal resources has not only promoted rapid economic development but also poses a potential threat to the ecological environment. The purpose of this study is to clarify the effects both of mining and land use types on the spatial distribution and particular sources of heavy metals in soil, using inverse distance weighted (IDW) and the Positive Matrix Factorization (PMF) model. A total of 99 topsoil and profile soil samples across different land use types and mining conditions were collected. The contamination of soil with Cd, Pb, and Hg in the research area was most severe, with the coefficient of variation (CV) of Hg being the largest, while also being heavily influenced by human activities. Severely polluted regions were mainly distributed in the center of the coal mining area, as well as near the highway. The contents of heavy metals for various land use patterns were ranked as follows: forestland > farmland > bare land > grassland > building land. Hg, Cd, Pb, Cr, and Zn had showed migration in the 0-60cm depth range, and the enrichment factors (EFs) of Cd, Pb, Hg, and As in the soil profile were the most significant. The PMF demonstrated that the contributions of industrial activities and atmospheric deposition, transportation and mining activities, agricultural activities, and natural sources accounted for 31.25%, 28.13%, 22.24%, and 18.38%, respectively. The migration and deposition of atmospheric particulate matter from coal mining, transportation, and coal combustion under winds triggered heavy metal contamination in semi-arid areas of northern China. This phenomenon has important implications for the prevention and reduction of heavy metal pollution through various effective measures in coal-mining cities in northern China.

Influence of compacting pressure on the electrical properties of ZnO and ZnO:Mn ceramics

Undoped and Mn-doped ZnO ceramics were prepared from the powders compacted at different pressures and sintered in air at high temperature. Their structural, optical, light emitting and electrical characteristics as well as the distribution of chemical elements were studied. It was found that an increase in compacting pressure stimulates an increase in direct current conductivity in both undoped and doped samples. In the case of doped samples, this effect was accompanied by a decrease in the height of potential barriers at the grain boundaries. It is found that electron concentration in ceramic grains, estimated from the modelling of infrared reflection spectra, remained relatively constant. The analysis of luminescence spectra and spatial zinc distribution revealed that the increase in compacting pressure results in the accumulation of interstitial zinc at the grain boundaries forming channels with enhanced conductivity. These findings provide an explanation for the evolution of electrical properties of ceramic samples with compacting pressure.

In-situ mapping of iron and titanium with the visible and near-infrared image spectrometer (VNIS) along the Yutu-2 rover traverse on the farside of the moon

In January 2019, China's Chang'E-4 probe successfully landed in the Von Kármán crater of the Moon's farside's South Pole-Aitken basin. Till August 2021, the Yutu-2 rover had worked for >32 lunar days. The Visible and Near-infrared Image Spectrometer (VNIS) is one of scientific payloads on board the rover that can collect in-situ spectral data. This provides a unique perspective for investigating the composition of the lunar surface materials. In this work, a local-scale FeO and TiO2 abundance mapping approach based on the in-situ VNIS data was proposed to utilize the fine spectral-spatial hyperspectral information. Improved FeO and TiO2 abundance inversion models were performed on each unshaded pixel to generate abundance maps. Experimental results obtained on 115 VNIS observation data along the Yutu-2's routing path confirm the effectiveness of the proposed approach, especially in the complex observation scenarios. Comparing with the in-orbit data products and the in-situ abundance results obtained by the reference methods, the effectiveness of the proposed in-situ FeO and TiO2 abundance mapping approach is validated. Furthermore, the proposed approach allows a detailed analysis of chemical properties and spatial distribution of lunar surface materials, and helps to discover abnormal targets according to the serial spectral observations along the rover's routing path, which reveals the great potential in more precise lunar surface material identification and analysis applications.

Location matters: spatial dynamics of tumor-infiltrating T cell subsets is prognostic in colon cancer.

Colon cancer is a heterogeneous disease and consists of various molecular subtypes. Despite advances in high-throughput expression profiling, limitations remain in predicting clinical outcome and assigning specific treatment to individual cases. Tumor-immune interactions play a critical role, with tumors that activate the immune system having better outcome for the patient. The localization of T cells within tumor epithelium, to enable direct contact, is essential for antitumor function, but bulk DNA/RNA sequencing data lacks spatial distribution information. In this study, we provide spatial T cell tumor distribution and connect these data with previously determined genomic data in the AC-ICAM colon cancer patient cohort. Colon cancer patients (n=90) with transcriptome data available were selected. We used a custom multiplex immunofluorescence assay on colon tumor tissue sections for quantifying T cell subsets spatial distribution in the tumor microenvironment, in terms of cell number, location, mutual distance, and distance to tumor cells. Statistical analyses included the previously determined Immunologic Constant of Rejection (ICR) transcriptome correlation and patient survival, revealing potential prognostic value in T cell spatial distribution. T cell phenotypes were characterized and CD3+CD8-FoxP3- T cells were found to be the predominant tumor-infiltrating subtype while CD3+FoxP3+ T cells and CD3+CD8+ T cells showed similar densities. Spatial distribution analysis elucidated that proliferative T cells, characterized by Ki67 expression, and Granzyme B-expressing T cells were predominantly located within the tumor epithelium. We demonstrated an increase in immune cell density and a decrease in the distance of CD3+CD8+ T cells to the nearest tumor cell, in the immune active, ICR High, immune subtypes. Higher densities of stromal CD3+FoxP3+ T cells showed enhanced survival outcomes, and patients exhibited superior clinical benefits when greater spatial distances were observed between CD3+CD8-FoxP3- or CD3+CD8+ T cells and CD3+FoxP3+ T cells. Our study's in-depth analysis of the spatial distribution and densities of major T cell subtypes within the tumor microenvironment has provided valuable information that paves the way for further research into the intricate relationships between immune cells and colon cancer development.

Analysis of Spatial distribution of Peatland Depth in Keub Village

Peat is an ecosystem that is formed due to biomass production that exceeds the decomposition process. The area of peat land in Aceh Province reaches 338,164 ha. Improper use of peatlands results in peatland degradation so that the thickness and depth of the peat soil decreases. This research aims to determine the map of changes in the distribution of peat depth classes and determine changes in the peat ecosystem classification map in Keub Village by comparing the peat depth map published by the Ministry of Environment and Forestry in 2019 with interpolation results using the inverse distance weight method. The results of this research showed that there was a change in the peat depth class and the area of distribution of the peat depth class between the peat depth class map published by the Ministry of Environment and Forestry and the interpolation results in Keub Village. Based on a comparison of the KLHK peat depth map with the interpolated map, it was also found that there was a change in the area of protected functional areas in the form of an increase in the number of areas.

Spatial Distribution Analysis of Cannabis-Infused Food and Drink Establishments in Pathum Thani Province, Thailand Through Geographic Information Systems

Spatial Distribution Analysis of Cannabis-Infused Food and Drink Establishments in Pathum Thani Province, Thailand Through Geographic Information Systems

ECMWF Lightning Forecast in Mainland Portugal during Four Fire Seasons

The study evaluated the ECMWF model ability in forecasting lightning in Portugal during four fire seasons (019–2022). The evaluation was made based on lightning data from the national lightning detector network, which was aggregated into resolutions of 0.5° and 1° over 3 h periods and analyzed from statistical indices using two contingency tables. The results showed that the model overestimates the lightning occurrence, with a BIAS greater than 1, with a success rate of 57.7% (49%) for a horizontal resolution of 1° (0.5°). The objective analysis was complemented by the spatial lightning distribution analysis, which indicated a time lag between the two data, i.e., the model started predicting lightning before its occurrence and finished the prediction earlier. Furthermore, such analysis revealed the lightning distribution being consistent with some weather patterns. The findings of this study provide insights into the applicability of the ECMWF lightning forecast data in the context of forecasting natural forest fires in Portugal.

Polycyclic aromatic hydrocarbons in coastal rivers in Jiangsu Province, China: Spatial distribution, source apportionment and human impacts

The ocean is the ultimate sink for all pollutants, rivers are important channels for land-based pollutants to enter the oceans. Riverine transport of polycyclic aromatic hydrocarbons (PAHs) to coastal seas in China poses environmental threats. This study examined the spatial and temporal distribution of PAHs in coastal rivers in Yancheng City in Jiangsu Province of China, with the aim of identifying their likely sources, concentrations, and influencing factors. Surface sediments were taken from the Xinyanggang River (XYR) and the Sheyang River (SYR). The concentrations of Ʃ16PAHs in river sediments were measured on average 477.05 ng/g dry weight (dw), with values varying from 2.18 to 6351.42 ng/g, indicating a moderate pollution level, with a dominance of high molecular weight (HMW) PAHs. The XYR exhibited significantly higher PAHs concentrations compared to the SYR. The key sources of PAHs were vehicle emissions (47.87%), coal and natural gas combustion (35.07%). Geographically weighted regression and redundancy analysis linked PAHs pollution to distinct land use patterns and socioeconomic indicators, highlighting urban land as the major contributor, driven by high urbanization and industrialization (70.91%). In XYR, industrial activities and transport emissions were major contributors, while in SYR, agricultural activities predominantly influenced PAHs pollution. Urgent mitigation strategies are needed to reduce PAHs pollution in river sediments, mitigating ecological and human risks associated with these contaminants.

Hidden Markov model for spatial analysis of three-dimensional mineralization distribution: Insights into magma flow and mineral exploration targets in the Jinchuan Ni-Cu-(PGE) sulfide deposit, China

The spatial distribution of mineralization includes significant clues about the magma/fluid flow process for ore formation. However, given the complex nature of the ore-forming process and its weak signature in the mineralization data, revealing the magma/fluid flow process in their mineralization footprint presents a considerable challenge. In this paper, we present a hidden Markov model (HMM) for the analysis of three-dimensional (3D) spatial distribution of mineralization. The HMM assumes the magma flow is a Markov process that is “hidden” in the “observable” mineralization features. Under this setting, the HMM quantifies the states of magma flow and links them as a whole in a probabilistic manner. This allows for the comprehensive combination of mineralization information, facilitating holistic inference of magma flow hidden in the mineralization signal. Based on the maximum likelihood principle, the magma trajectories and the associated injection points are inferred from the HMM. The proposed model is applied to spatial analysis of the mineralization in the world-class Jinchuan Ni-Cu-(PGE) magmatic sulfide deposit in NW China. Based on the 3D mineralization data interpolated from drill assays, the HMM infers magma trajectories and the associated injection points at Jinchuan, which indicate the Jinchuan deposit was formed by a multiple magma conduit system that comprises four independent injection points of magma ingress. According to the identified magma trajectories and injection points, four sites beneath the injection points and along the extension of magma trajectories are considered promising for future mineral exploration. With the insights gained from this case study, the proposed HMM can serve as an effective tool in the exploration information system to unveil magma/fluid flow history and guide exploration efforts toward concealed, deep-seated mineralization.

Artificial intelligence-based analysis of tumor-infiltrating lymphocyte spatial distribution for colorectal cancer prognosis.

Artificial intelligence (AI) technology represented by deep learning has made remarkable achievements in digital pathology, enhancing the accuracy and reliability of diagnosis and prognosis evaluation. The spatial distribution of CD3 + and CD8 + T cells within the tumor microenvironment has been demonstrated to have a significant impact on the prognosis of colorectal cancer (CRC). This study aimed to investigate CD3 CT (CD3 + T cells density in the core of the tumor [CT]) prognostic ability in patients with CRC by using AI technology. The study involved the enrollment of 492 patients from two distinct medical centers, with 358 patients assigned to the training cohort and an additional 134 patients allocated to the validation cohort. To facilitate tissue segmentation and T-cells quantification in whole-slide images (WSIs), a fully automated workflow based on deep learning was devised. Upon the completion of tissue segmentation and subsequent cell segmentation, a comprehensive analysis was conducted. The evaluation of various positive T cell densities revealed comparable discriminatory ability between CD3 CT and CD3-CD8 (the combination of CD3 + and CD8 + T cells density within the CT and invasive margin) in predicting mortality (C-index in training cohort: 0.65 vs. 0.64; validation cohort: 0.69 vs. 0.69). The CD3 CT was confirmed as an independent prognostic factor, with high CD3 CT density associated with increased overall survival (OS) in the training cohort (hazard ratio [HR] = 0.22, 95% confidence interval [CI]: 0.12-0.38, P <0.001) and validation cohort (HR = 0.21, 95% CI: 0.05-0.92, P = 0.037). We quantify the spatial distribution of CD3 + and CD8 + T cells within tissue regions in WSIs using AI technology. The CD3 CT confirmed as a stage-independent predictor for OS in CRC patients. Moreover, CD3 CT shows promise in simplifying the CD3-CD8 system and facilitating its practical application in clinical settings.

Spatial Distribution and Accessibility Analysis of Primary School Facilities in Mega Cities: A Case Study of Chengdu

High-quality and equitable primary education services promote the building of a harmonious socialist society and are an important basis for improving people’s quality of life and promoting high-quality and sustainable regional development. Here, we take Chengdu City as a test area, integrate data from multiple sources, use the random forest model to simulate the distribution data of primary school-age children in Chengdu City in 2020, and use the kernel density estimation method and the multi-traffic mode two-stage floating catchment area method to measure the spatial distribution characteristics and accessibility of primary school educational facilities in Chengdu City and combine the imbalance index and spatial autocorrelation analysis, examination of the equalization of the distribution of primary school educational facilities, and the correlation between school-age population and accessibility. The results show that in the past decade, the population of Chengdu has grown rapidly, and the number of primary school-age children has also been increasing. The overall distribution of primary school-age children in Chengdu presents a decentralized pattern of “one point with multiple cores”, with the population decreasing from the center to the periphery, and the population distribution dominates the spatial distribution of primary school facilities, which also highlights the imbalance in the construction of primary school facilities to some extent (S = 0.257), which was mainly manifested by the fact that the central-eastern part of the city has more primary school facilities, while the western part has fewer. In addition, the results of both accessibility and autocorrelation analyses show that the overall accessibility of the central circle of Chengdu was high, while the accessibility of the second and third circles was at a lower level and below, with very obvious cross-regional and cross-circle differences. This study can not only provide more accurate recommendations for the allocation of educational facilities but also serve as a reference for evaluating the spatial equity of other public services in the city.

VOC absorption in supramolecular deep eutectic solvents: Experiment and molecular dynamic studies

The absorption of volatile organic compounds (VOCs) using supramolecular deep eutectic solvents (SUPRADES), composed of randomly methylated β-cyclodextrin (RAMEB) and conventional organic solvents, was systematically investigated from vapor-liquid experiments to molecular dynamic simulations. The obtained partition coefficients suggest that the combination of RAMEB and ethylene glycol (REG, mole ratio 1:40) significantly improves the absorption ability of ethylene glycol (EG), making REG even the most efficient absorbent for chloroform and limonene. By studying the key factors affecting the absorption process, we found that increasing the concentration of VOCs in the gas phase, lowering the absorption temperature or reducing the water content of the absorbent are effective in improving absorption. Regeneration test shows that the absorption ratio of chloroform using REG is maintained around 99% under six absorption–desorption cycles, highlighting its high absorption efficiency and stability. The absorption mechanism was then deeply explored by molecular dynamic simulation. It was found that the hydrogen bond between RAMEB and EG hinders the aggregation of neighboring RAMEB molecules, helping RAMEB to form stable and homogeneous solvent with EG. In addition, the interaction energy analysis demonstrates that van der Waals forces contribute the most to the absorption of chloroform by REG. Finally, the radical distribution function analysis was used to visualize the 2-dimensional molecule distribution of SUPRADES systems and the spatial distribution analysis verified the formation of RAMEB/chloroform inclusion complexes in the absorption process. The obtained results indicate that REG is a highly efficient and easy recyclable solvent for VOCs absorption.