Spatial Distribution Of Population Research Articles

The Spatiotemporal Correlation between Human Activity Intensity and the Evolution of Ecosystem Service Value in the Songnen Plain, China

For the main grain-producing areas worldwide that balance multi-tasks of grain production, ecological protection, and economic development, quantitatively revealing the correlation between human activity intensity (HAI) and ecosystem service value (ESV) is conducive to formulating adapted ecological protection policies and promoting the coordinated development of the regional economy, society, and ecosystem. In this paper, we took the Songnen Plain of China as an example, employed a modified Equivalent Factor Method (integrating socio-economic data, the normalized difference vegetation index (NDVI), and land use data), and the HAI Assessment Model (based on the data of land use, night-time light, and population spatial distribution) to measure the ESV and HAI in the Songnen Plain of China for the years 1990, 1995, 2000, 2005, 2010, 2015, and 2020. We further applied the standard deviational ellipse method, the coupled coordination degree model, and the bivariate spatial autocorrelation models to reveal the spatiotemporal dynamics and correlation characteristics of ESV and HAI. The results showed the following: (1) Temporally, the ESV declined from 950.96 billion yuan in 1990 to 836.31 billion yuan in 2015, and then increased to 864.60 billion yuan in 2020, with the total loss attributed to the significant decline in the ESV of the natural ecosystem. Spatially, the ESV in the western and northeastern regions was relatively high, with a significant increase in the northeast. (2) HAI showed an upward trend from 1990 to 2020, while the high HAI levels gradually shrank after reaching the peak in 2000. Low HAI levels were mainly distributed in the northeast and southwest, aligning with the ecological space, while high HAI levels were distributed in the middle and southeast. (3) The interaction between ESV and HAI was marked by a negative correlation, transitioning from conflict to coordination. The spatial pattern of HAI and ESV showed H (HAI)-L (ESV) and L-H clustering, with H-H and L-L scattered distributions. This study contributes to providing a framework, methods, and suggestions for the sustainable planning and utilization of land and ecological protection in order to offer scientific references for the Songnen Plain, other major grain-producing areas, and related studies.

TME-analyzer: a new interactive and dynamic image analysis tool that identified immune cell distances as predictors for survival of triple negative breast cancer patients

Spatial distribution of intra-tumoral immune cell populations is considered a critical determinant of tumor evolution and response to therapy. The accurate and systemic search for contexture-based predictors would be accelerated by methods that allow interactive visualization and interrogation of tumor micro-environments (TME), independent of image acquisition platforms. To this end, we have developed the TME-Analyzer, a new image analysis tool, which we have benchmarked against 2 software tools regarding densities and networks of immune effector cells using multiplexed immune-fluorescent images of triple negative breast cancer (TNBC). With the TME-Analyzer we have identified a 10-parameter classifier, predominantly featuring cellular distances, that significantly predicted overall survival, and which was validated using multiplexed ion beam time of flight images from an independent cohort. In conclusion, the TME-Analyzer enabled accurate interactive analysis of the spatial immune phenotype from different imaging platforms as well as enhanced utility and aided the discovery of contextual predictors towards the survival of TNBC patients.

Spatial distribution of tumour immune infiltrate predicts outcomes of patients with high-risk soft tissue sarcomas after neoadjuvant chemotherapy

BackgroundAnthracycline-based neoadjuvant chemotherapy (NAC) may modify tumour immune infiltrate. This study characterized immune infiltrate spatial distribution after NAC in primary high-risk soft tissue sarcomas (STS) and investigate association with prognosis. MethodsThe ISG-STS 1001 trial randomized STS patients to anthracycline plus ifosfamide (AI) or a histology-tailored (HT) NAC. Four areas of tumour specimens were sampled: the area showing the highest lymphocyte infiltrate (HI) at H&E; the area with lack of post-treatment changes (highest grade, HG); the area with post-treatment changes (lowest grade, LG); and the tumour edge (TE). CD3, CD8, PD-1, CD20, FOXP3, and CD163 were analyzed at immunohistochemistry and digital pathology. A machine learning method was used to generate sarcoma immune index scores (SIS) that predict patient disease-free and overall survival (DFS and OS). FindingsTumour infiltrating lymphocytes and PD-1+ cells together with CD163+ cells were more represented in STS histologies with complex compared to simple karyotype, while CD20+ B-cells were detected in both these histology groups. PD-1+ cells exerted a negative prognostic value irrespectively of their spatial distribution. Enrichment in CD20+ B-cells at HI and TE areas was associated with better patient outcomes. We generated a prognostic SIS for each tumour area, having the HI-SIS the best performance. Such prognostic value was driven by treatment with AI. InterpretationThe different spatial distribution of immune populations and their different association with prognosis support NAC as a modifier of tumour immune infiltrate in STS.Funding: Pharmamar; Italian Ministry of Health [RF-2019-12370923; GR-2016-02362609]; 5x1000 Funds—2016, Italian Ministry of Health; AIRC Grant [ID#28546].

P-276 Endometrial microbiome diversity and the local macrophages populations during the mid-secretory phase

Abstract Study question Are there any quantitative associations between endometrial macrophages populations and microorganisms’ diversity? Summary answer The quantities and spatial distribution of endometrial macrophages populations correlated significantly with several microbiome diversity indices. What is known already Numerous studies have linked the relative abundance of Lactobacilli with a receptive endometrium, while the presence of multiple other bacterial species has been implicated in implantation failure. Another determinant of endometrial receptivity is the local immune cell composition and its inflammatory status. Knowing that the microbiome affects the immune system, it is worth studying the potential interplay between bacterial composition and immune cell populations in the endometrium during its receptive state. The present study aimed to investigate associations between the quantity and distribution of endometrial macrophages populations and the local microbiome diversity during the mid-secretory phase of the menstrual cycle. Study design, size, duration This prospective observational study was conducted between April 2021 and January 2023. Endometrial biopsies were collected from 25 female patients of reproductive age on day 7 after luteinising hormone surge. Eligibility criteria included no endometrial pathologies, no history of recent or chronic inflammatory or infectious disease, no recent antibiotic treatment, and no endocrinological, autoimmune or oncological conditions. Participants/materials, setting, methods Half of each biopsy was used for immunohistochemistry with CD11c + (Proteintech) and CD163 + (Quartett) to reveal pro- and anti- inflammatory macrophages, respectively. Their quantities and spatial distribution were analysed by HALO® image analysis software. The remaining endometrial tissue underwent DNA isolation and subsequent 16S rRNA (v4-v5 region) gene sequencing to determine endometrial microbiota composition. Alpha diversity indices - Good’s coverage, Shannon and phylogenic diversity - were evaluated and tested for correlation with the macrophages metrics. Main results and the role of chance The observed median percentage and range of the studied macrophages populations in the endometrial stroma were: 1.16% (2.98) CD11c+ macrophages and 1.96% (4.48) CD163+ macrophages. The evaluated alpha diversity indices were: 0.99±0.01 Good’s coverage, 2.53±1.20 Shannon and 38.56±15.43 phylogenic diversity.The CD11c+ macrophages percentage was not related to the microbial diversity of the studied samples. The percentage of the CD163+ macrophages, however, showed significant correlation with the Good’s coverage alpha diversity index (R = 0.397, p = 0.04). The median distance between CD11c+ and CD163+ cells in the endometrial stroma was 63.7µm (108.36) and it was significantly related to the Shannon alpha diversity index (R=-0.347, p = 0.05) and phylogenic diversity whole tree index (R=-0.367, p = 0.05).In summary, the anti-inflammatory macrophages percentage in the mid-secretory endometrial stroma is positively related to the local microbial diversity. Moreover, the distances between the pro- and anti-inflammatory macrophages populations in the endometrium are negatively associated to Shannon and PD whole tree alpha diversity indices. Limitations, reasons for caution The results of this study should be confirmed in a larger study population. Wider implications of the findings This study’s findings indicate that there is a correlation of the endometrial macrophages quantity and stromal distribution with the endometrial microbiome diversity. The association between these determinants of endometrial receptivity could help in understanding the fine tuning of the endometrium for accepting the embryo. Trial registration number The current research was funded by the National Science Fund, Ministry of Education, Bulgaria, Contract № KP-06-N53/14/16.11.2021.

Shapes of dark matter haloes with discrete globular cluster dynamics: The example of NGC 5128 (Centaurus A)

Context. Within the Λ cold dark matter (ΛCDM) cosmology, dark matter haloes are expected to deviate from spherical symmetry. The particular shape of a galactic halo reflects the environment and mass assembly history of its host, as well as the nature of dark matter. Constraining halo shapes at large galactocentric distances is challenging because of the low density of luminous tracers. The well-studied massive early-type galaxy NGC 5128, also known as Centaurus A (Cen A), has a large number of radial velocity measurements for globular clusters (GCs) and planetary nebulae (PNe) extending over a vast area of its extended low-surface-brightness stellar halo. Aims. In this work, we aim to determine the deviation from spherical symmetry of the dark matter halo of Cen A at 5 Re using its GCs as kinematic tracers of the gravitational potential. Methods. We investigated the largest photometric catalogue of GC candidates in order to accurately characterise the spatial distribution of the relaxed population of GCs. To investigate the presence of non-relaxed structures in the kinematic catalogue of GCs, we used the relaxed point-symmetric velocity field as determined by the host’s PNe population. We used anisotropic Jeans modelling under axisymmetric assumptions together with the Gaussian likelihood and GCs as discrete tracers. The gravitational potential is generated by flattened stellar and dark matter distributions. We leveraged the different orbital properties of the blue and red GCs – such as rotation and velocity anisotropy – to model both populations separately. By minimising χ2, we iteratively find the best-fit parameters. Results. We find that the discrete kinematics of the GCs are consistent with being drawn from an underlying relaxed velocity field determined from PNe. The best-fit parameters of the gravitational potential recovered from the blue and red GCs separately agree well and we use them to compute the final results: M200 = 1.86−0.691.61 × 1012 M⊙, M⋆/LB = 2.98−0.78+0.96, and the flattening qDM = 1.45−0.53+0.78. Both GC populations show mild rotation, with red having a slightly stronger rotational signature and radially biased orbits, and blue GCs preferring negative velocity anisotropy. Conclusions. An oblate or a spherical dark matter halo of NGC 5128 is strongly disfavoured by our modelling.

Feasibility of anomalous event detection based on Mobile Spatial Statistics: A study of six cases in Japan

One of the primary goals of disaster risk management is to minimize the loss of life in the event of a disaster. To reduce the number of victims in disasters is important to know the amount of exposed population to a hazard. Similarly, population distribution in real-time is required to estimate post-disaster needs and resources for disaster relief. In this study, we explore the use of Mobile Spatial Statistics (MSS) as the basis to acquire offline and online population data and detect anomalies that may relate to a disaster. For instance, mobile spatial data could identify sudden changes in the number of people indicating an anomalous event or change in population dynamics. Here we use the Matrix Profile (MP) method in time-series analysis to test the feasibility of detecting anomalies in the MSS data. We selected mass gatherings and disaster events with rapid and slow onset and small and large scales. We discuss the applicability of this method for real-time anomaly detection of spatial population distribution within the context of disaster risk management. Our results show that the applicability of the MP method in anomaly detection is sensitive to the size of the areas used during monitoring and analysis, the subsequence length and the threshold applied.

Using random forests to uncover the predictive power of distance-varying cell interactions in tumor microenvironments.

Tumor microenvironments (TMEs) contain vast amounts of information on patient's cancer through their cellular composition and the spatial distribution of tumor cells and immune cell populations. Exploring variations in TMEs between patient groups, as well as determining the extent to which this information can predict outcomes such as patient survival or treatment success with emerging immunotherapies, is of great interest. Moreover, in the face of a large number of cell interactions to consider, we often wish to identify specific interactions that are useful in making such predictions. We present an approach to achieve these goals based on summarizing spatial relationships in the TME using spatial K functions, and then applying functional data analysis and random forest models to both predict outcomes of interest and identify important spatial relationships. This approach is shown to be effective in simulation experiments at both identifying important spatial interactions while also controlling the false discovery rate. We further used the proposed approach to interrogate two real data sets of Multiplexed Ion Beam Images of TMEs in triple negative breast cancer and lung cancer patients. The methods proposed are publicly available in a companion R package funkycells.

Middle to late Holocene human societies on the eastern margin of the Eurasian Steppe, and their adaptation to environmental changes

The impact of environmental changes on the development of human societies in the Eurasian Steppe is not well understood over the Holocene timescale. In this study, we have reported the phytoliths, grain size, and weight loss on ignition for an aeolian soil profile in the Liao River Basin at the eastern margin of the Eurasian Steppe. The profiles spanned the middle and late Holocene based on AMS 14C dating. By employing the summed radiocarbon probability distribution of archaeological sites and kernel density analysis, the spatial and temporal distributions of human populations and settlements were investigated in order to analyze the rise and fall of ancient cultures. Our findings indicated that the environment in the Liao River Basin underwent three stages of change. From 6700 to 5400 cal yr BP, the climate was warm and humid. The climate suddenly became cold and dry from 5400 to 4900 cal yr BP. The climate fluctuated, with a general tendency towards cold and dry conditions, from 4900 cal yr BP to 1700 cal yr BP. In addition, human societies in the region underwent significant changes, with rapid agricultural development and population growth in the warm and humid environment of the Middle Neolithic (6700–5000 yr BP). However, during the Late Neolithic (5000–4000 yr BP), the living environment suddenly became cold and dry, which limited the development of human society and drastically reduced its population. Nevertheless, the resilience of human societies continued to increase, and in the Bronze Age (4000–2000 yr BP), even in an overall cold and dry living environment, human societies still developed and their population increased sharply. Changes in the East Asia Summer Monsoon were an important driver of cultural change, and our study emphasizes the complex human-environment interactions that shaped societal development on the Eurasian Steppe.

The Spatial and Temporal Distribution, Flow Network and its Characteristics of Population in Henan Province

Based on the WorldPop center population data set and the dynamic monitoring data of China 's floating population, this paper analyzes the spatial and temporal changes of regional population and the characteristics of flow network and its influencing factors with the help of ArcGIS spatial analysis and mapping function and geographic detector model. It shows that: The regional difference of population spatial distribution in Henan Province is obvious and extremely uneven, and the population agglomeration speed of Zhengzhou metropolitan zone is obviously accelerated. The regional differentiation of population change in Henan Province is serious, and the population attraction of Zhengzhou is increasing, The population of Undertake industrial transfer zone such as Shangqiu and Zhoukou continued contraction. The population growth area and the population contraction area are more concentrated in space, showing the characteristics of spatial agglomeration. In addition, economic factors are still the main driving factors of population change in Henan Province. The influence of service industry on population change is increasing, and the explanatory power of traditional agriculture, forestry, animal husbandry and fishery and manufacturing industry on population change is decreasing. The integrated development of secondary and tertiary industries will further affect the future population distribution pattern of each region.

A global map of gullied hillslopes on Mars

The distribution of gullies on Mars has been used to support different modes of formation involving CO2, H2O or entirely dry processes. We mapped the extent of gullied hillslope using a global mosaic of ConTeXt camera (CTX) at 6 m/pixel and High Resolution Imaging Science Experiment (HiRISE) browse products at ∼3 m/pixel. Our new global catalog of gullied hillslopes allows for quantitative, area-based analysis of gullies both at global and regional scale, which was not possible with point-based or more localized previous datasets. We analyzed aspect and gradient information derived from MOLA topography for every mapped gullied hillslope. We have confirmed the trends identified in previous works, which are that the mean gradient of gullied hillslopes is lower than 30°, the angle of repose of dry material on Mars, and that the preferred aspect of gullied hillslopes is latitude-dependent, with a shift between pole-facing to equator-facing happening around 40° in both hemispheres. We established a hierarchy of factors that can explain the global distribution of gullied hillslopes: Latitude is the strictest control because gullies are constrained between 26°-83°S and 28°-76°N. The availability of steep slopes is a strong control over gully distribution, and we observed that gullied hillslopes aspect reflects the orientation of large regional reliefs, which implies that hillslope aspect is less of a factor than the hillslope gradient in explaining gully distribution. We analyzed the correlation of gully distribution with a subsurface water ice consistency map, and we found that gullies are preferentially distributed on areas with some ground ice rather than no ice at all. We identified for the first time a bias toward an east-facing trend for southern hemisphere gullies poleward of ∼40° of latitude. We also linked our gullied hillslopes dataset with a global crater morphometry dataset: 63% of the gullied area on Mars is found in craters, and we find that the area covered by gullies in a given crater is positively correlated with the depth and diameter ratio of this crater.Our observations point toward a complex interplay between local slope, insolation, and thermal properties of the substrate to explain the spatial distribution of the current population of gullies. Finally, we have assessed the very high resolution (sub-meter) imagery coverage of gullies to be 36% and that the repeated coverage reaches 21% of gullies, hence this would need expanding to better understand the spatial trends in active gullies.

Study on Spatialization and Spatial Pattern of Population Based on Multi-Source Data—A Case Study of the Urban Agglomeration on the North Slope of Tianshan Mountain in Xinjiang, China

Study on Spatialization and Spatial Pattern of Population Based on Multi-Source Data—A Case Study of the Urban Agglomeration on the North Slope of Tianshan Mountain in Xinjiang, China

Population analysis using GIS software tools A case study of Chengdu

Population analysis using GIS software tools A case study of Chengdu

Abstract PO2-25-05: Spatial multiplexing of protein biomarkers for immune cell profiling of the tumor microenvironment with ChipCytometry

Abstract Understanding the spatial distribution of key immune cell populations is critical in advancing our understanding of cancer and the development of novel therapeutics. Historically, the spatial analysis of the tumor microenvironment (TME) has been limited to relatively low-plex immunohistochemical (IHC) or immunofluorescent (IF) assays, which were inadequate for deep immune cell profiling of the TME. Here, we present the analysis of fresh-frozen human breast tissue using spatial multiplexing technology called ChipCytometry, which combines iterative immuno-fluorescent staining using open-source antibodies for quantitative measure of virtually unlimited protein biomarkers on the same sample and high dynamic range imaging to facilitate quantitative phenotyping with single-cell resolution. In addition to traditional pathology review of the high-plex dataset, subsequent image analysis can be done using open-source or commercial software for advanced spatial analyses, including cluster analysis, neighborhood analysis and advanced data visualization. The results show precise expression levels for each of the protein biomarkers in the assay for each individual cell within the sample while maintaining spatial information about each cell. Dozens of immune cell subtypes were identified and quantified based on protein expression profiles. Spatial analysis of the samples revealed quantifiable heterogeneity of immune cell infiltration within the tumor samples, demonstrating the utility of the ChipCytometry platform for in-depth immune profiling in clinical samples. The ChipCytometry platform enables simultaneous detection of multiple protein biomarkers on a single tissue section for deep immune cell profiling in the TME. Combined with the single-cell spatial information, such datasets provide an opportunity for the discovery of new complex multiplexed biomarker signatures to inform therapeutic development and personalized medicine. Citation Format: Benton Berigan. Spatial multiplexing of protein biomarkers for immune cell profiling of the tumor microenvironment with ChipCytometry [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-25-05.

‘Conga lines’ of Ediacaran fronds: insights into the reproductive biology of early metazoans

Late Ediacaran strata from Newfoundland, Canada (~574–560 Ma) document near-census palaeocommunities of some of the earliest metazoans. Such preservation enables reproductive strategies to be inferred from the spatial distribution of populations of fossilized benthic organisms, previously revealing the existence of both propagule and stoloniferous reproductive modes among Ediacaran frondose taxa. Here, we describe ‘conga lines’: linear arrangements of more than three closely spaced fossil specimens. We calculate probabilistic models of point maps of 13 fossil-bearing bedding surfaces and show that four surfaces contain conga lines that are not the result of chance alignments. We then test whether these features could result from passive pelagic propagules settling in the lee of an existing frond, using computational fluid dynamics and discrete phase modelling. Under Ediacaran palaeoenvironmental conditions, preferential leeside settlement at the spatial scale of the conga lines is unlikely. We therefore conclude that these features are novel and do not reflect previously described reproductive strategies employed by Ediacaran organisms, suggesting the use of mixed reproductive strategies in the earliest animals. Such strategies enabled Ediacaran frondose taxa to act as reproductive generalists and may be an important facet of early metazoan evolution.

Biogeographical and seasonal distribution of pteropod populations in the western and central Mediterranean Sea inferred from sediment traps

Pteropods are a group of cosmopolitan holoplanktic gastropods that produce an aragonite shell and play an important role in both marine ecosystems and geochemical cycles. In addition to being affected by anthropogenic impacts that include warming and changes in carbonate system parameters, the Mediterranean Sea is considered to be understudied concerning pteropods dynamics and abundances. This work aims to document the modern spatial and temporal distributions of pteropods populations in the Northwestern and Central Mediterranean Sea (Gulf of Lions and Strait of Sicily), respectively. We present data from two sediment-trap records that cover the timeframe between early 1996 and early 2004 for the Gulf of Lions and late 2013 to late 2014 for the Sicily Strait. A total of 843 pteropod shells and 18 different species were identified. Limacina inflata, Creseis virgula and Creseis clava were the most abundant species in the Gulf of Lions, while in the Sicily Strait, C. conica replaced C. clava as the most abundant species. These taxons represented around 70% of the total individuals identified in both sites. Overall, our results suggest a greater pteropod abundance in the Gulf of Lions than in the Sicily Strait, most likely due to enhanced food conditions. In the Gulf of Lions, maximum fluxes occurred in autumn (32.5% of the annual pteropod fluxes registered in October), while in the Sicily Strait peak fluxes occurred in winter (30.5% of the annual pteropod fluxes registered in January). Comparison of temporal changes pteropod fluxes with satellite sea surface temperature (SST), and chlorophyll-a concentration suggest a possible positive effect of high algal accumulation and cool water conditions in the Strait of Sicily on the main pteropod groups. In turn, no clear relationships between pteropod groups, SST and chlorophyll-a were identified in the Gulf of Lions, highlighting the effect of salinity and carbonate system parameters. Overall, and despite the limitations associated with the use of sediment traps for pteropod population monitoring, the consistency of our results with the literature supports the use of sediment traps as useful tools for documenting the diversity and temporal distribution of pteropods.

The impact of the spatial population distribution on economic growth: Evidence from the United States

AbstractWe introduce a new class of measures called spatial population concentration (SPC) designed to quantify how many people live on average within a given radius of every person within a geographic area. The distinguishing feature relative to existing measures is that ours are the first to satisfy scale invariance, replication invariance, sensitivity to transfers, aggregativity, sensitivity to neighborhoods, invariance to uninhabited regions, concurrently. We calculate the SPC measure at the US county level for various radii and identify that the strongest relationship with subsequent economic growth can be found for a 25‐km radius. Interacting SPC with diverse infrastructure metrics does not alter the optimal radius. This indicates that regional policies such as infrastructure projects which influence density should strategically target the 25‐km distance range to maximize the growth impact. We also show that the importance of SPC has declined over time.

Immunolabeling-compatible PEGASOS tissue clearing for high-resolution whole mouse brain imaging.

Novel brain clearing methods revolutionize imaging by increasing visualization throughout the brain at high resolution. However, combining the standard tool of immunostaining targets of interest with clearing methods has lagged behind. We integrate whole-mount immunostaining with PEGASOS tissue clearing, referred to as iPEGASOS (immunostaining-compatible PEGASOS), to address the challenge of signal quenching during clearing processes. iPEGASOS effectively enhances molecular-genetically targeted fluorescent signals that are otherwise compromised during conventional clearing procedures. Additionally, we demonstrate the utility of iPEGASOS for visualizing neurochemical markers or viral labels to augment visualization that transgenic mouse lines cannot provide. Our study encompasses three distinct applications, each showcasing the versatility and efficacy of this approach. We employ whole-mount immunostaining to enhance molecular signals in transgenic reporter mouse lines to visualize the whole-brain spatial distribution of specific cellular populations. We also significantly improve the visualization of neural circuit connections by enhancing signals from viral tracers injected into the brain. Last, we show immunostaining without genetic markers to selectively label beta-amyloid deposits in a mouse model of Alzheimer's disease, facilitating the comprehensive whole-brain study of pathological features.

Partition refinement of WorldPop population spatial distribution data method: A case study of Zhuhai, China.

Currently, the core idea of the refined method of population spatial distribution is to establish a correlation between the population and auxiliary data at the administrative-unit level and, then, refine it to the grid unit. However, this method ignores the advantages of public population spatial distribution data. Given these problems, this study proposed a partition strategy using the natural break method at the grid-unit level, which adopts the population density to constrain the land class weight and redistributes the population under the dual constraints of land class and area weights. Accordingly, we used the dasymetric method to refine the population distribution data. The study established a partition model for public population spatial distribution data and auxiliary data at the grid-unit level and, then, refined it to smaller grid units. This method effectively utilizes the public population spatial distribution data and solves the problem of the dataset being not sufficiently accurate to describe small-scale regions and low resolutions. Taking the public WorldPop population spatial distribution dataset as an example, the results indicate that the proposed method has higher accuracy than other public datasets and can also describe the actual spatial distribution characteristics of the population accurately and intuitively. Simultaneously, this provides a new concept for research on population spatial distribution refinement methods.

Abstract 5389: Development of T-cell exclusion in melanoma

Abstract Immune checkpoint inhibitors (ICIs), which prevent immune cell exhaustion and boost an antitumor response, have shown remarkable treatment efficacy in patients with advanced melanoma. However, its efficacy is limited by the emergence of resistance associated with an immunosuppressive tumor microenvironment (TME). The contribution of abnormal tumor vasculature to limited immune cell infiltration into the tumor core has been reported but the mechanisms of its development are still elusive. We analyzed how tumor angiogenesis affects the immune cell exclusion at different time points of primary melanoma using syngeneic murine melanomas. The spatial distribution of various immune cell populations and vascular integrity were analyzed in whole tumor cross-sections via multiplex immunofluorescence staining. We found that the exclusion pattern of CD8+ T cells was less evident with a balanced distribution across the whole tumor regions at the early stage. However, as the tumor grows, there is a pronounced accumulation of CD8+ T cells at the tumor periphery with a conspicuous absence in the core. Tumor blood vessels were structurally uniform and functionally stable in the early developmental tumor but became unstable and leaky as the tumor progressed, which was associated with the development of CD8+ T-cell exclusion. To understand the mechanism underlying vascular regulation of immune exclusion during tumor progression, we will investigate the expression of genes related to tumor angiogenesis using spatial transcriptomic analysis and RNA sequencing of endothelial cells (CD45+CD31-) sorted from the murine melanomas. These results highlight the contribution of spatial tumor vascular destabilization to the T-cell exclusion development, implying the potential of targeting tumor vasculature to enhance immune activation and the therapeutic efficacy of ICI in melanoma. Citation Format: Ha-Ram Park, Hee Won Yang, Minah Kim. Development of T-cell exclusion in melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5389.

Abstract 5497: Towards a drag and drop spatial biology workflow: Introducing sample reinterrogation as a conduit for the progressive development and on-line analysis of high parameter spatial biology data

Abstract The potential for spatial biology in cancer research is understood and edified. With it we can understand the tumor microenvironment, unravel responsiveness to drug treatments and cell therapies, and ultimately stratify patients for targeted treatment and clinical trial enrollment. Yet, researchers exploring spatial biology may be discouraged by what can be a resource intensive exercise, and most importantly, a commitment of high value patient samples. Furthermore, the design of reagent panels used to study samples is not trivial, and a specimen’s unique biomarker expression profile may require adjustments. Here we present a novel solution that permits sample re-interrogation and in-flight adjustments of reagent panels in our spatial biology workflow. The CellScape™ platform for Precise Spatial Multiplexing paired with VistaPlex™ Assay Kits provide a ready-to-use cyclic multiplex immunofluorescence (IF) solution to interrogate fresh frozen and FFPE tissue samples. Tissues are mounted in enclosed fluidic chambers, while staining and imaging are conducted on the CellScape instrument. The experiment requires no additional autostainer equipment and is divided into separate staining and imaging rounds. The end user may therefore pause between rounds and conduct inter-round analyses, which can then guide decisions of whether and how to continue the experiment. To illustrate the benefit of this approach, we present a use case in which we applied VistaPlex antibody panels to reveal the spatial distribution of major immune cell populations. Inter-round analysis and conclusions were then drawn from this preliminary phenotype map before successive rounds of rationally planned staining were conducted to further deepen the depth and breadth of spatial phenotyping. The CellScape sample reinterrogation feature is a pragmatic spatial biology solution that optimizes the use of precious resources, whilst allowing researchers to generate informed decisions about antibody panel designs almost in real time. This enhanced utility may reduce the resistance to spatial biology among researchers working with samples that are limited or irreplaceable. Citation Format: Matthew H. Ingalls, Xenia Meshik, Charles E. Jackson, Kayla E. Cashion, Arne Christians, Anke Brix, Marcus Boettcher, J Spencer Schwarz, Oliver Braubach. Towards a drag and drop spatial biology workflow: Introducing sample reinterrogation as a conduit for the progressive development and on-line analysis of high parameter spatial biology data [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5497.