Distribution Patterns Research Articles

Age-dependent distribution of IgA and IgG antibody-secreting cells in the pharyngeal tonsil of the Bactrian camel

The pharyngeal tonsil, located in the nasopharynx, can effectively defend against pathogens invading the body from the upper respiratory tract and play a crucial role in mucosal immunity of the respiratory tract. Immunoglobulin A (IgA) and Immunoglobulin G (IgG) serve as key effector molecules in mucosal immunity, exhibiting multiple immune functions. This study aimed to investigate the distribution patterns and age-related alterations of IgA and IgG antibody-secreting cells (ASCs) in the pharyngeal tonsils of Bactrian camels. Twelve Alashan Bactrian camels were categorized into four age groups: young (1-2 years, n=3), pubertal (3-5 years, n=3), middle-aged (6-16 years, n=3) and old (17–20 years, n=3). The distribution patterns of IgA and IgG ASCs in the pharyngeal tonsils of Bactrian camels of different ages were meticulously observed, analyzed and compared using immunohistochemical and statistical methods. The results revealed that IgA ASCs in the pharyngeal tonsils of all age groups were primarily clustered or diffusely distributed in the reticular epithelium and its subepithelial regions (region A) and around the glands (region C), scattered in the subepithelial regions of non-reticular epithelium (region B), and sporadically distributed in the interfollicular regions (region D). Interestingly, the distribution pattern of IgG ASCs in the pharyngeal tonsils closely mirrored that of IgA ASCs. The distribution densities of IgA and IgG ASCs in these four regions were significantly decreased in turn (P<0.05). However, IgA ASCs exhibited significantly higher densities than IgG ASCs in the same region (P<0.05). Age-related alterations indicated that the distribution densities of IgA and IgG ASCs in each region of the pharyngeal tonsils exhibited a trend of initially increasing and subsequently decreasing from young to old camels, reaching a peak in the pubertal group. As camels age, there was a significant decrease in the densities of IgA and IgG ASCs in all regions of the pharyngeal tonsils (P<0.05). The results demonstrate that the reticular epithelium and its subepithelial regions in the pharyngeal tonsils of Bactrian camels are the primary regions where IgA and IgG ASCs colonize and exert their immune functions. These regions play a pivotal role in inducing immune responses and defending against pathogen invasions in the pharyngeal tonsils. IgA ASCs may be the principal effector cells of the mucosal immune response in the pharyngeal tonsils of Bactrian camels. Aging significantly reduces the densities of IgA and IgG ASCs, while leaving their distribution patterns unaffected. These findings will provide valuable insights for further investigations into the immunomorphology, immunosenescence, and response mechanisms of the pharyngeal tonsils in Bactrian camels.

Distribution patterns, risk assessment and potential sources of heavy metals in sediment in the Qiongzhou Strait, China

Risk assessment and pollutant source analysis are crucial tools for the management and protection of coastal ecosystems. The distribution patterns, risk assessment, and potential sources of heavy metals (Cd, Cr, Fe, Ni, Cu, Zn, As, Hg, and Pb) in surface sediment were analyzed in the Qiongzhou Strait, China, in summer and autumn of 2022. Heavy metals in autumn showed higher ecological risk than that in summer. Seasonal shifts in ocean currents may result in variations in heavy metal accumulation and dispersion. Cd and Hg were the priority heavy metals found, and according to the Positive Matrix Factorization results, the study area contains five sources of pollution, with natural sources, shipping-related activities, and industrial activities being the primary contributors. This study indicated that pollutants from adjacent areas should be considered for managing the environmental quality of Qiongzhou Strait.

Distribution patterns and origins of organophosphate esters in soils from different climate systems on the Tibetan Plateau

Organophosphate esters (OPEs) are extensively applied in various materials as flame retardants and plasticizers, and have high biological toxicity. OPEs are detected worldwide, even in distant polar regions and the Tibetan Plateau (TP). However, few studies have been performed to evaluate the distribution patterns and origins of OPEs in different climate systems on the TP. This study investigated the distribution characteristics, possible sources, and ecological risks of OPEs in soils from the different climate systems on the TP and its surroundings. The total concentrations of OPEs in soil varied from 468 to 17,451 pg g-1 dry weight, with greater concentrations in southeast Tibet (monsoon zone), followed by Qinghai (transition zone) and, finally, southern Xingjiang (westerly zone). OPE composition profiles also differed among the three areas with tri-n-butyl phosphate dominant in the westerly zone and tris(2-butoxyethyl) phosphate dominant in the Indian monsoon zone. Correlations between different compounds and altitude, soil organic carbon, or longitude varied in different climate zones, indicating that OPE distribution originates from both long-range atmospheric transport and local emissions. Ecological risk assessment showed that tris(2-chloroethyl) phosphate and tri-phenyl phosphate exhibited medium risks in soil at several sites in southeast Tibet. Considering the sensitivity and vulnerability of TP ecosystems to anthropogenic pollutants, the ecological risks potentially caused by OPEs in this region should be further assessed.

Environmental heterogeneity caused by large-scale cultivation of Pyropia haitanensis shapes multi-group biodiversity distribution in coastal areas

The response of marine biodiversity to mariculture has long been a research focus in marine ecology. However, the effects of seaweed cultivation on biological community assembly are poorly understood, especially in diverse communities with distinct ecological characteristics. In this study, we used environmental DNA metabarcoding to investigate the spatial distribution patterns of bacterial, protistan, and metazoan diversity, aiming to reveal the mechanisms of community assembly in the Pyropia haitanensis cultivation zone along the Fujian coast, China. We found that, compared with the biological communities in control zones, those in P. haitanensis cultivation zones exhibited stronger geographic distance-decay patterns and displayed more complex and stable network structures. Deterministic processes (environmental selection) played a more important role in the assembly of bacterial, protistan, and metazoan communities in P. haitanensis cultivation zones, especially metazoan communities. Variance partitioning analysis showed that environmental variables made greater contributions to the diversity of the three types of communities within the P. haitanensis cultivation zones than in the control zones. Partial least squares path modeling analysis identified nitrate‑nitrogen (NO3-N), pH, particulate organic carbon (POC), and dissolved organic carbon (DOC) as the key environmental variables affecting biodiversity. Overall, the environmental heterogeneity caused by the large-scale cultivation of P. haitanensis could be the crucial factor influencing the composition and structure of various biological communities. Our results highlight the importance of the responses of multi-group organisms to the cultivation of seaweed, and provide insights into the coexistence patterns of biodiversity at the spatial scale.

Composition, diel dynamic and biotic-abiotic interaction of marine neustonic zooplankton in the oligotrophic South China Sea

Neuston, situated at the air-sea interface, stands as a crucial frontier in the realm of the global warming. Despite its unique habitat, there remains a need to substantiate the composition, diel dynamic and biotic-abiotic interaction of neustonic zooplankton in the tropical seas. In this study, we present rare observational data on neustonic zooplankton (0–20 cm) in the oligotrophic tropical South China Sea (SCS) during the summer of 2022. A total of eighteen samples were collected and analyzed, revealing the presence of fourteen taxa from eight phyla. The most prevalent group was Cypridina, accounting for 33.7% of the total abundance, followed by copepods (29.0%) and jellyfish (10.9%). Within copepods, the genus Pontella exhibited the highest relative abundance (38.0%). Additionally, each neuston taxon displayed unique diel distribution patterns. Cypridina was the most abundant taxon during the night (40.4%), while it shifted to copepod dominance during the day (50.4%). Among copepods, genus Pontella and larvae were dominant groups at night (44.7%) and during the day (30.0%), respectively. Moreover, a multivariate biota-environment analysis demonstrated that temperature, pH, dissolved oxygen and Si(OH)4 significantly impacted neuston composition. Notably, both jellyfish and sea snails showed a significant positive correlation with temperature, suggesting their potential dominance in the neuston community in response to future global warming in the oligotrophic tropical seas. This study lays a robust foundation for recognizing the neuston community in the oceanic SCS, and helps evaluate the long-term risks to neuston habitats under climate changes.

Simulation Study of Sand Casting by Using Runner &amp; Gates Modification in Gating System

Abstract: Sand casting remains a prevalent method for manufacturing complex metal components due to its costeffectiveness and versatility. However, optimizing the gating system, particularly through runner riser modification, is crucial for enhancing casting quality and minimizing defects. This study employs computer simulation techniques to investigate the effects of various modifications in the gating system on the solidification behavior and quality of castings. Through numerical simulations using advanced software tools, different configurations of the gating system are analyzed and compared, focusing on parameters such as flow rate, velocity distribution, and solidification patterns. The results reveal insights into the effectiveness of runner riser modification strategies in reducing defects like shrinkage and porosity, thereby improving the overall casting quality. Additionally, the study explores the trade-offs between different modification approaches in terms of cost, complexity, and performance. These findings contribute to the optimization of sand-casting processes, offering practical guidance for engineers and manufacturers aiming to enhance product quality and efficiency.

Active targeted delivery of theranostic thermo/pH dual-responsive magnetic Janus nanoparticles functionalized with folic acid/fluorescein ligands for enhanced DOX combination therapy of rat glioblastoma.

Doxorubicin (DOX), a chemotherapy drug, has demonstrated limited efficacy against glioblastoma, an aggressive brain tumor with resistance attributed to the blood-brain barrier (BBB). This study aims to overcome this challenge by proposing the targeted delivery of magnetic Janus nanoparticles (MJNPs) functionalized with folic acid ligands, fluorescent dye, and doxorubicin (DOX/MJNPs-FLA). The properties of these nanoparticles were comprehensively evaluated using bio-physiochemical techniques such as Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), zeta potential analysis, high-resolution transmission electron microscopy (HR-TEM), vibrating sample magnetometry (VSM), fluorescence microscopy, MTT assay, hemolysis assay, and liver enzyme level evaluation. Dual-controlled DOX release was investigated under different pH and temperature conditions. Additionally, the impact of DOX/MJNPs-FLA on apoptosis induction in tumor cells, body weight, and survival time of cancerous animals was assessed. The targeted delivery system was assessed using C6 and OLN-93 cell lines as representatives of cancerous and healthy cell lines, respectively, alongside Wistar rat tumor-bearing models. Results from Prussian blue staining and confocal microscopy tests demonstrated the effective targeted internalization of MJNPs-FLA by glioblastoma cells. Additionally, we investigated the biodistribution of the nanoparticles utilizing fluorescence imaging techniques. This enabled us to track the distribution pattern of MJNPs-FLA in vivo, shedding light on their movement and accumulation within the biological system. Furthermore, the combination of chemotherapy and magnetic hyperthermia exhibited enhanced efficacy in inducing apoptosis, as evidenced by the increase of the pro-apoptotic Bax gene and a decrease in the anti-apoptotic Bcl-2 gene. Remarkably, this combination treatment did not cause any hepatotoxicity. This study highlights the potential of DOX/MJNPs-FLA as carriers for therapeutic and diagnostic agents in the context of theranostic applications for the treatment of brain malignancies. Additionally, it demonstrates the promising performance of DOX/MJNPs-FLA in combination treatment through passive and active targeting.

An integrated taxonomic revision of Ctonoxylon (Coleoptera, Curculionidae, Scolytinae) reveals new Malagasy species originating from multiple recent colonisations of the island

Ctonoxylon is a strictly Afrotropical genus of bark beetles breeding under bark of rainforest trees and lianas. A taxonomic revision of the genus included a molecular phylogenetic analysis of ten species based on three gene fragments and was compared to a morphology-based tree topology for all 24 currently recognised species. Four species are described as new to science: Ctonoxylon torquatum, sp. nov., Ctonoxylon tuberculatum, sp. nov., Ctonoxylon quadrispinum, sp. nov., all from Madagascar, and Ctonoxylon pilosum, sp. nov. from Cameroon. Ctonoxylon hirsutum Hagedorn, 1910, stat. rev. is resurrected from synonymy with C. flavescens Hagedorn, 1910, and C. atrum Browne, 1965 stat. rev. from its synonymy with C. methneri Eggers, 1922 (as C. hamatum Schedl, 1941). The following species have new synonymies suggested: Ctonoxylon festivum Schedl, 1941 (= C. dentigerum Schedl, 1941, syn. nov.), C. methneri Eggers, 1922 (= C. hamatum Schedl, 1941, syn. nov., = C. griseum Schedl, 1941, syn. nov.), C. montanum Eggers, 1922 (= C. longipilum Eggers, 1935, syn. nov., = C. nodosum Eggers, 1940, syn. nov.), C. camerunum Hagedorn, 1910 (= C. conradti Schedl, 1939, syn. nov.), and C. spinifer Eggers, 1920 (= C. setifer Eggers, 1920, syn. nov.). New country records are noted for C. festivum (Tanzania), C. flavescens (Uganda), C. camerunum (Liberia), C. crenatum Hagedorn, 1910 (Democratic Republic of the Congo), C. spathifer Schedl, 1941 (Ghana), C. atrum (Cameroon), and C. spinifer (Madagascar), with patterns in distribution and colonisation of Madagascar discussed. An identification key with pictures of all species is provided.

Phenotypic and Genotypic Antibiotic Resistance Patterns of Clinical Shigella Isolates from Tehran, Iran

Background: The emergence of multidrug-resistant (MDR) Shigella is a health concern in both developed and developing countries. The indiscriminate use of antibiotics without considering resistance patterns has led to the emergence of resistant strains. Objectives: This study aimed to investigate the phenotypic and genotypic patterns of antibiotic resistance and virulence gene distribution in Shigella isolates from patients in Tehran, Iran. Methods: In this cross-sectional study, 60 Shigella isolates were collected from patients referred to Milad Hospital and Pasargad Laboratory in Tehran. The isolates were gathered over four months, from February 2023 to June 2023. After biochemical and genetic confirmation of the isolates, the disk diffusion method was employed to determine antibiotic resistance patterns. The distribution of beta-lactamase genes (blaCTX-M1, blaCTX-M2, blaCTX-M8, blaSHV, blaTEM, and blaOXA) and virulence genes (ial, virF, invE, sigA, and pic) was investigated in Shigella isolates using the multiplex PCR method. SPSS statistical software version 22 was used for data analysis. Results: Thirty-six percent of isolates were found to be MDR. The highest rate of resistance was against tetracycline (90%) and ampicillin (80%). The lowest resistance rate was against azithromycin (1.9%) and amikacin (7.1%). The blaCTX-M1 and blaCTX-M8 genes were more prevalent, detected in 38.3% and 50% of the isolates, respectively. However, the blaSHV and blaCTX-M2 genes were not detected in any of the isolates. Additionally, 32% of the MDR isolates harbored both the blaCTX-M1 and blaCTX-M8 genes simultaneously. The distribution of virulence genes ial, virF, invE, sigA, and pic in the studied isolates was 28.3%, 85%, 68.3%, 81.7%, and 15%, respectively. Conclusions: The present study emphasizes the increasing trend of MDR Shigella isolates. Therefore, serious measures are needed to prevent the spread of resistant genes. Furthermore, the detection of virulence factors could help in controlling shigellosis, which is a significant global health issue.

Monitoring Land Use Changes in the Yellow River Delta Using Multi-Temporal Remote Sensing Data and Machine Learning from 2000 to 2020

The Yellow River Delta (YRD), known for its vast and diverse wetland ecosystem, is the largest estuarine delta in China. However, human activities and climate change have significantly degraded the wetland ecosystem in recent decades in the YRD. Therefore, an understanding of the land use modifications is essential for the efficient management and preservation of ecosystems in this region. This study utilized time series of remote sensing data and the extreme gradient boosting method to generate land use maps of the YRD from 2000 to 2020. Several methods, including transition matrix, land use dynamic degree, and standard deviation ellipse, were employed to explore the characteristics of land use transitions. The results underscore significant spatial variations in land use over the past two decades. The most rapid increase was observed in built-up area, followed by terrestrial water and tidal flats, while unutilized land experienced the fastest decrease, followed by forest–grassland. The spatial distribution patterns of agricultural land, built-up area, terrestrial water, and forest–grassland demonstrated stronger directionality compared to other land use types. The wetlands have expanded in size and improved in structure. Unutilized land has been converted into artificial wetlands comprising ponds, reservoirs, salt ponds, shrimp and crab ponds, and natural wetlands featuring mudflats and forest–grassland. The wetland conservation efforts after 2008 have proven very effective, playing a positive role in ecological and environmental preservation, as well as in regional sustainable development.

The Thermoelastic Dynamic Response of a Rod Due to a Moving Heat Source under the Fractional-Order Thermoelasticity Theory

In this paper, the thermoelastic behavior of a rod made of an isotropic material under the action of a moving heat source was investigated using a new theory of thermoelasticity related to fractional-order time with two relaxation times. A mathematical model of the one-dimensional thermoelasticity problem was established based on the new thermoelasticity theory. We considered the symmetry of the material, and the fractional-order thermoelasticity control equation was given. Subsequently, the control equations were solved and analyzed using the Laplace transform and its inverse transform. This study examined the effects of fractional-order parameters, time, two thermal relaxation times, and the speed of movement of the heat source on the displacement, temperature, and stress distribution patterns in the rod.

Three-Dimensional Hepatocyte Spheroids: Model for Assessing Chemotherapy in Hepatocellular Carcinoma

BACKGROUND: Three-dimensional cellular models provide a more comprehensive representation of in vivo cell properties, encompassing physiological characteristics and drug susceptibility. METHODS: Primary hepatocytes were seeded in ultra-low attachment plates to form spheroids, with or without tumoral cells. Spheroid structure, cell proliferation, and apoptosis were analyzed using histological staining techniques. In addition, extracellular vesicles were isolated from conditioned media by differential ultracentrifugation. Spheroids were exposed to cytotoxic drugs, and both spheroid growth and cell death were measured by microscopic imaging and flow cytometry with vital staining, respectively. RESULTS: Concerning spheroid structure, an active outer layer forms a boundary with the media, while the inner core comprises a mass of cell debris. Hepatocyte-formed spheroids release vesicles into the extracellular media, and a decrease in the concentration of vesicles in the culture media can be observed over time. When co-cultured with tumoral cells, a distinct distribution pattern emerges over the primary hepatocytes, resulting in different spheroid conformations. Tumoral cell growth was compromised upon antitumoral drug challenges. CONCLUSION: Treatment of mixed spheroids with different cytotoxic drugs enables the characterization of drug effects on both hepatocytes and tumoral cells, determining drug specificity effects on these cell types.

Observations on Gender Variance in Chinese Community Children Measured by the Gender Identity Questionnaire for Children.

Few studies have examined how gender variance (GV), broadly defined as gender identity and behaviors (e.g., activities and preferences) that do not correspond with culturally defined gender norms, manifests in community samples, particularly in children and outside Western contexts. We present data based on the Gender Identity Questionnaire for Children (GIQC; Johnson et al., 2004) among 461 Chinese community children (4-12years old) to gauge how well the GIQC serves as a measure of GV and the prevalence of GV. We examined the descriptive scores of GV, its relationship to a gender-typing measure that has been validated in Chinese children (the Child Play Behavior and Activity Questionnaire, CPBAQ), the scores on the GIQC of children whose gender is incongruent with birth-assigned sex, and the binned category distributions (from gender-variant to gender-conforming) in comparison to a Canadian community sample (van der Miesen et al., 2018). The Chinese children on average scored toward the gender-conforming end and children assigned female at birth showed more GV than children assigned male at birth. More importantly, the GIQC appears to be a reliable and sensitive measure of GV in the Chinese sample. GIQC scores correlated significantly with CPBAQ scores and showed a very similar reliability coefficient, gender difference effect size, and bin distribution pattern as the Canadian reference sample. Also, children reported as gender/sex incongruent had the most gender-variant GIQC scores. Although clinically gender-referred Chinese children are required to establish culturally specific cutoff points, these findings provide initial evidence for the characteristics of GV, the applicability of the GIQC as a measure of GV in Chinese community children, and the comparisons of GIQC categories between Chinese and Canadian community samples.

Iron deposition in subcortical nuclei of Parkinson's disease: A meta-analysis of quantitative iron-sensitive magnetic resonance imaging studies.

Iron deposition plays a crucial role in the pathophysiology of Parkinson's disease (PD), yet the distribution pattern of iron deposition in the subcortical nuclei has been inconsistent across previous studies. We aimed to assess the difference patterns of iron deposition detected by quantitative iron-sensitive magnetic resonance imaging (MRI) between patients with PD and patients with atypical parkinsonian syndromes (APSs), and between patients with PD and healthy controls (HCs). A systematic literature search was conducted on PubMed, Embase, and Web of Science databases to identify studies investigating the iron content in PD patients using the iron-sensitive MRI techniques (R2* and quantitative susceptibility mapping [QSM]), up until May 1, 2023. The quality assessment of case-control and cohort studies was performed using the Newcastle-Ottawa Scale, whereas diagnostic studies were assessed using the Quality Assessment of Diagnostic Accuracy Studies-2. Standardized mean differences and summary estimates of sensitivity, specificity, and area under the curve (AUC) were calculated for iron content, using a random effects model. We also conducted the subgroup-analysis based on the MRI sequence and meta-regression. Seventy-seven studies with 3192 PD, 209 multiple system atrophy (MSA), 174 progressive supranuclear palsy (PSP), and 2447 HCs were included. Elevated iron content in substantia nigra (SN) pars reticulata (P <0.001) and compacta (P <0.001), SN (P <0.001), red nucleus (RN, P <0.001), globus pallidus (P <0.001), putamen (PUT, P=0.009), and thalamus (P=0.046) were found in PD patients compared with HCs. PD patients showed lower iron content in PUT (P <0.001), RN (P=0.003), SN (P=0.017), and caudate nucleus (P=0.027) than MSA patients, and lower iron content in RN (P=0.001), PUT (P <0.001), globus pallidus (P=0.004), SN (P=0.015), and caudate nucleus (P=0.001) than PSP patients. The highest diagnostic accuracy distinguishing PD from HCs was observed in SN (AUC: 0.85), and that distinguishing PD from MSA was found in PUT (AUC: 0.90). In addition, the best diagnostic performance was achieved in the RN for distinguishing PD from PSP (AUC: 0.84). Quantitative iron-sensitive MRI could quantitatively detect the iron content of subcortical nuclei in PD and APSs, while it may be insufficient to accurately diagnose PD. Future studies are needed to explore the role of multimodal MRI in the diagnosis of PD. PROSPERO; CRD42022344413.

Numerical Study on Electromagnetic Thermal Performance of Non-Metallic Armoured Optoelectronic Cable Winch System

Non-metallic armoured optoelectronic cable winch systems (NAOCWSs) play critical roles in facilitating signal transmission and powering subsea equipment. Due to the varying depths in these applications, deploying the entire cable length is unnecessary. However, the portion of the cable that remains coiled around the winch can generate an electromagnetic field, which may interfere with signal transmission and induce electromagnetic heating. This can lead to elevated temperatures within the system, affecting the cable’s lifespan. Consequently, this study examines the distributions of magnetic and temperature fields within the NAOCWS with different currents (10–30 A) and numbers of winding layers (1–10). Findings indicate that the magnetic flux density (MFD) changes periodically, and the period is closely related to the distance between the cables. At the centre of the cable, the flux density is minimum. Temperature distribution correlates with both current amplitude and the number of winding layers, where an increase in either parameter amplifies the temperature variance between the edge and intermediate cables within the same layer. The current does not affect the internal temperature distribution pattern. With the number of winding layers determined, the layer where the highest temperature of the system is located is well defined and does not vary with current.

Reduced-dimensional prediction method for the axial aerodynamic forces in the off-design operation of near-critical CO2 centrifugal compressors

In the high-load centrifugal compressor of near-critical CO2 (NcCO2) power-generation cycle, the overload of axial aerodynamic force causes significant harms to the structural safety and operational stability of turbomachinery components. Based on a transcritical CO2 compressor of a MWt-class simple recuperated cycle, we numerically studied the aero-thermodynamic characteristics of back-cavity leakage, and discussed the physical model of the axial aerodynamic forces in off-design operation of NcCO2 compressors. Finally, reduced-dimensional prediction method for the axial aerodynamic forces in the near-critical CO2 compressor was developed. Wherein, the Japikse's method was used to estimate the primary aerodynamic loads of centrifugal impeller, and a 1-D radial equilibrium equation with angular velocity ratio was derived to predict the thrust force acting on the impeller back disk. Furtherly, based on the near-wall distribution pattern of angular velocities and physical property of Rankine vortex, a semi-empirical model of angular velocity ratio was introduced and completed the model of back-disk force. In validation, the reduced-dimensional prediction method exhibited satisfactory accuracy with perfectly acceptable errors compared to the refined CFD simulations. Thereby, a reduced-dimensional prediction method for the axial aerodynamic forces was developed for the economical and agile analysis of NcCO2 compressors in engineering practices.

Which contributes more to the relict flora distribution pattern in East Asia, geographical processes or climate change? New evidence from the phylogeography of Rehderodendron kwangtungense

BackgroundRelict species are important for enhancing the understanding of modern biogeographic distribution patterns. Although both geological and climatic changes since the Cenozoic have affected the relict flora in East Asia, the contributions of geographical processes remain unclear. In this study, we employed restriction-site associated DNA sequencing (RAD-seq) and shallow genome sequencing data, in conjunction with ecological niche modeling (ENM), to investigate the spatial genetic patterns and population differentiation history of the relict species Rehderodendron kwangtungense Chun.ResultsA total of 138 individuals from 16 populations were collected, largely covering the natural distribution of R. kwangtungense. The genetic diversity within the R. kwangtungense populations was extremely low (HO = 0.048 ± 0.019; HE = 0.033 ± 0.011). Mantel tests revealed isolation-by-distance pattern (R2 = 0.38, P < 0.001), and AMOVA analysis showed that the genetic variation of R. kwangtungense occurs mainly between populations (86.88%, K = 7). Between 23 and 21 Ma, R. kwangtungense underwent a period of rapid differentiation that coincided with the rise of the Himalayas and the establishment of the East Asian monsoon. According to ENM and population demographic history, the suitable area and effective population size of R. kwangtungense decreased sharply during the glacial period and expanded after the last glacial maximum (LGM).ConclusionOur study shows that the distribution pattern of southern China mountain relict flora may have developed during the panplain stage between the middle Oligocene and the early Miocene. Then, the flora later fragmented under the force of orogenesis, including intermittent uplift during the Cenozoic Himalayan orogeny and the formation of abundant rainfall associated with the East Asian monsoon. The findings emphasized the predominant role of geographical processes in shaping relict plant distribution patterns.

Assessing trends and burden of occupational exposure to asbestos in the United States: a comprehensive analysis from 1990 to 2019.

This study aimed to analyze the trends and burden of occupational exposure to asbestos in the United States (U.S.) from 1990 to 2019, focusing on mortality rates, geographic distribution, age and sex patterns, and causes of death. Data on the number of deaths attributable to occupational exposure to asbestos were collected from 1990 to 2019 in the U.S. Joinpoint analysis was conducted to assess trends over time, and regression models were applied to calculate annual percentage changes (APC) and annual average percentage changes (AAPC). Geographic distribution was examined using mapping techniques. Age and sex patterns were analyzed, and causes of death were identified based on available data. From 1990 to 2019, the overall number of deaths due to occupational exposure to asbestos in the U.S. increased by 20.2%. However, age-standardized mortality rates (ASMR) and age-standardized disability-adjusted life years (DALYs) rates (ASDR) exhibited a decline over the same period. Geographic analysis revealed differences in the number of deaths across states in 2019, with California reporting the highest number of fatalities. Age-specific mortality and DALYs showed an increase with age, peaking in older age groups. Tracheal, bronchus, and lung cancer were the leading causes of death attributed to asbestos exposure, with increasing trends observed over the past five years. The study highlights significant trends and burden in occupational exposure to asbestos in the U.S., including overall increases in mortality rates, declining ASMR and ASDR, geographic disparities, age and sex patterns, and shifts in causes of death. These findings underscore the importance of continued monitoring and preventive measures to mitigate the burden of asbestos-related diseases.

Multi-scale population analysis unit construction method considering scene feature variability and long/short-term patterns in spatiotemporal population activities

ABSTRACT Differences in the spatial scale and component elements of urban scenes affect the analysis of spatiotemporal changes in population distribution (PD) patterns. Fixed scales and geometric forms constrained previous analyses of PD and spatiotemporal changes, which neglected the realistic characteristics of urban scenarios. These limitations hinder the ability to capture the diversity and spatiotemporal representation of PD patterns across multiple spatial scales. This study developed a multi-spatial scale population analysis unit (PAU) construction method considering the scenario heterogeneity and long/short-term patterns of spatiotemporal population changes (PC). Initially, we decompose the multi-scale changes in population time series patterns and their relationships with scene features along the temporal dimension to analyze the primary and secondary factors. Starting from the temporal characteristics of the PD and PC, we established a validation and correction method for the factors. Finally, combined with a multi-feature clustering method, a multi-scale PAU construction method driven by scene feature factors is proposed. Experiments were conducted at different spatial scales in both routine and emergent scenarios. The results indicated that this method can help to obtain more homogeneous analysis regions and enhance the stability and phase pattern representations of changes in PDs, thereby improving the interpretability of analytical results.

Qualea grandiflora Mart. (Vochysiaceae) seed reserves and aluminum: Usage and mobilization during germination and seedling development

AbstractQualea grandiflora Mart. is an aluminum (Al)‐accumulating Cerrado species with a metabolic dependency on Al. This study aimed to determine the presence and concentration of Al and other reserve components in Q. grandiflora seeds, as well as their respective distribution patterns, mobilization, and usage during germination and seedling growth. Thus, the concentration of Al and other minerals in seeds, seedlings, and soils was measured. Also, histochemical and energy‐dispersive X‐ray spectroscopy (EDS) analyses were performed to observe the distribution of Al, proteins, and lipids in Q. grandiflora seeds and seedlings. Additionally, the concentration of proteins and lipids was assessed as well. Hence, even in soils with low exchangeable Al3+, Q. grandiflora seeds accumulated about 6.43 g of Al/kg of dry matter (DM) together with considerable concentrations of N, P, K, Ca, and Mg. Exogenous Al had no effect on the germination properties of Q. grandiflora seeds. Furthermore, approximately 60% of the seed Al was translocated to seedling leaves. Proteins and lipids were the main organic reserves in Q. grandiflora seeds. The histochemical analysis revealed that the bulk of Al in seeds was in the cotyledons, which were also the location sites of proteins and lipids. Proteins and lipids were the primary source of energy and carbon for seedling growth. Therefore, fatty acids, proteins, and Al could play a central role during seed germination and seedling establishment, which could help to explain why this species is one of the most widespread plants in the Cerrado.