Search Results (177)

In regions where transportation and the economy are closely integrated, optimizing network structure and enhancing synergy are vital for regional integration. This paper constructs a dual-factor linkage network using enterprise investment and liner shipping data to analyze linkage strength and synergy effects among cities in the Greater Bay Area. The findings reveal that (1) a core-periphery structure exists, with core cities dominating resource flows while secondary cities remain weak. The logistics network is led by Hong Kong and Shenzhen, while the capital flow network showcases the dominance of Hong Kong, Shenzhen, and Guangzhou. (2) From 2016 to 2021, interactions between transportation and the economy deepened, showing strong correlations in logistics and capital flows among core cities and between core and edge cities, but weaker correlations with sub-core and edge cities. Core cities stabilize regional transportation and economy, fostering agglomeration, while sub-core cities are more reliant on them, indicating a need for better resource balance. (3) The spatio-temporal coupling analysis reveals significant heterogeneity in flows among cities, with many exhibiting antagonistic couplings outside core areas. This study enhances understanding of synergy mechanisms in transportation and economic networks, offering insights for optimizing layouts and improving capital flow efficiency. Full article

Green Stormwater Infrastructure (GSI), as a nature-based solution, has gained widespread recognition for its role in mitigating urban flood risks and enhancing resilience. Equitable spatial distribution of GSI remains a pressing challenge, critical to harmonizing urban hydrological systems and maintaining ecological balance. However, the complexity of matching GSI supply with urban demand has limited comprehensive spatial assessments. This study introduces a quantitative framework to identify priority zones for GSI deployment and to evaluate supply–demand dynamics in the Guangdong–Hong Kong–Macao Greater Bay Area (GBA) using a coupled coordination simulation model. Clustering and proximity matrix analysis were applied to map spatial relationships across districts and to reveal underlying mismatches. Findings demonstrate significant spatial heterogeneity: over 90% of districts show imbalanced supply–demand coupling. Four spatial clusters were identified based on levels of GSI disparity. Economically advanced urban areas such as Guangzhou and Shenzhen showed high demand, while peripheral regions like Zhaoqing and Huizhou were characterized by oversupply and misaligned allocation. These results provide a systematic understanding of GSI distribution patterns, highlight priority intervention areas, and offer practical guidance for large-scale, equitable GSI planning. Full article

As a flagship city of China’s reform and opening-up policy and the core engine of the Guangdong–Hong Kong–Macao Greater Bay Area, Shenzhen faces dual challenges of economic development and ecological conservation during its rapid urbanization. This study systematically investigates the relationship between urbanization and ecological quality in this high-density megacity over the past three decades (1990–2020) using multi-temporal Landsat imagery, incorporating an enhanced Remote Sensing Ecological Index (RSEI), impervious surface extraction techniques, and a Coupling Coordination Degree (CCD) model. Key findings include: (1) Impervious surfaces expanded from 458.15 km² to 709.23 km², showing a tri-phase pattern of rapid expansion, steady infill, and slight contraction, with an annual growth rate of 1.47%; (2) Ecological quality exhibited a “decline-recovery” trajectory, with RSEI values decreasing from 0.477 (1990) to 0.429 (2000) before rebounding to 0.491 (2020), demonstrating phased ecological fluctuations and restoration; (3) The CCD between urbanization and ecological environment improved significantly from “marginal coordination” (0.548) to “primary coordination” (0.636), forming a distinct “west-high-east-low” spatial pattern with significant clustering effects. This study reveals a novel three-dimensional synergistic pathway (“industrial upgrading-spatial optimization-ecological restoration”) for sustainable development in megacities, establishing the “Shenzhen Paradigm” for ecological governance in rapidly urbanizing regions worldwide. Full article

Understanding the historical peak situation and the rules for CO₂ emissions from buildings helps to formulate reasonable building mitigation strategies, accelerating the achievement of the Chinese government’s carbon peak goal. As developed regions, cities in the Guangdong–Hong Kong–Macao Great Bay Area (GBA) provide valuable reference cases. This study quantified the historical building CO₂ emissions of GBA cities and analyzed the contribution of driving factors using the Kaya identity and logarithmic mean Divisia index. Furthermore, we assessed the historical peak situation using the MK trend test method and discussed the reasons behind the inter-city difference in the peak situation shown by the environmental Kuznets curve. The results indicate that the building-related CO₂ emissions of the GBA will slowly increase to 96.90 Mt CO₂ by 2020 and that P&C buildings accounted for a larger proportion of emissions. Emission factors and population made the largest positive and negative contributions, respectively, to this total. At the city level, Guangzhou, Shenzhen, and Hong Kong ranked as the top three sources of building CO₂ emissions. Hong Kong peaked, Dongguan and Macao plateaued, and other cities maintained either slow or quick growth. CO₂ emissions unit area, per capita building CO₂ emissions, and building CO₂ emissions reached a peak in that order. This study provides a valuable reference for formulating a city-level path showing building CO₂ emissions peaks. Full article

As an economically active region, the Guangdong–Hong Kong–Macao Greater Bay Area (GBA) faces dual challenges of carbon and air pollution reduction. Existing studies predominantly focus on single pollutants or engineering pathways, lacking systematic analyses of multi-scale synergistic effects. This study investigates the spatiotemporal distributions, driving factors, and synergistic effects of CO₂ and volatile organic compounds (VOCs) at the multi-scale of urban agglomerations, cities, and industries, using global Moran’s index, standard deviational ellipse, logarithmic mean divisa index decomposition model, and Tapio decoupling model. The results show that the average annual growth rate of CO₂ (7.4%) was significantly higher than that of VOCs (4.5%) from 2000 to 2020, and the industrial sector contributed more than 70% of CO₂ and VOC emissions, with the center of gravity of emissions migrating to Dongguan. Industrial energy intensity improvement emerged as the primary mitigation driver, with Guangzhou and Shenzhen demonstrating the highest contribution rates. Additionally, CO₂ and VOC reduction show two-way positive synergy, and the path of “energy intensity enhancement–carbon and pollution reduction” in the industrial sector is effective. Notably, the number of strong decouplings of the economy from CO₂ (11 times) is much higher than the number of strong decouplings of VOCs (3 times), suggesting that the synergy between VOC management and economic transformation needs to be strengthened. This study provides scientific foundations for phased co-reduction targets and energy–industrial structure optimization, proposing regional joint prevention and control policy frameworks. Full article

Background: Breast milk confers essential passive immunity to infants, particularly during viral pandemics. This study investigates dynamic changes in SARS-CoV-2-specific antibodies and proteome in the breast milk of mothers infected with either the wild-type or Omicron variants, addressing gaps in longitudinal dynamics and conserved or variant-specific immune responses. Methods: A prospective cohort of 22 lactating mothers infected with Omicron variant (December 2022–January 2023) was analyzed alongside a published dataset of wild-type-infected mothers (January–May 2020). Breast milk samples were collected at eight time points (1, 4, 7, 14, 21, 28, 35, 42 days post-infection) from the Omicron cohort for ELISA quantification of SARS-CoV-2-specific IgA, IgG, and IgM. Proteomic analysis was conducted for both cohorts. Results: Macronutrient composition remained stable throughout the post-infection period. SARS-CoV-2-specific IgA and IgG demonstrated biphasic kinetics, rapidly rising by day 14 (IgA: 0.03 to 0.13 ng/mL; IgG: 0.91 to 37.00 ng/mL) and plateauing through day 42. In contrast, IgM levels remained unchanged. Proteomic profiling identified 135 proteins associated with IgA/IgG dynamics, including variant-specific and conserved proteins. Conclusions: Breast milk maintains nutritional integrity while mounting robust immune responses during SARS-CoV-2 infection. These findings underscore breastfeeding as a safe and protective practice during COVID-19. Full article

Background: COVID-19, caused by SARS-CoV-2, poses a significant threat to human health. Vaccines designed for T-cell epitopes play an important role in eliminating the virus. However, T cell epitope screening often requires the use of a large number of peripheral blood mononuclear cells (PBMCs) from infected or convalescent patients, and if MHC humanized mice can be used for epitope screening, they will not have to wait for enough PBMCs to be available to screen for epitopes, thus buying time for epitope confirmation and vaccine design. Methods: In this study, we used SARS-CoV-2 BA.5 to infect HLA-A11/DR1, C57BL/6, hACE2 mice, and detected body weight changes, viral load, and pathological changes after infection. Fourteen days after the HLA-A11/DR1 and C57BL/6 mice were immunized against inactivated viruses, IgG antibodies were detected in mouse serum using ELISA, and IFN-γ produced by peptide stimulation of splenocytes was detected by ELISpot. Results: There is no obvious pathogenic phenotype of SARS-CoV-2 infection in HLA-A11/DR1 mice. Specific IgG antibodies were detected in serum after immunization of inactivated virus in both HLA-A11/DR1 and C57BL/6 mice, but specific IFN-γ was detected in splenocytes of HLA-A11/DR1 mice. Conclusions: Although HLA-A11/DR1 mice are unable to replicate the virus effectively in vivo, they are able to generate cellular immune responses after immunization inactivated viruses. Therefore, it can be used as a tool to substitute for human PBMCs in epitope screening, thus shortening the timeliness of T cell epitope screening and obtaining the immunogenicity information of new epitopes in a timely manner. Full article

P450 enzymes are integral to insect physiology, metabolism, hormone regulation, and adaptation to environmental challenges. By leveraging transcriptomic and genomic data, this study characterized the expression of 68 unique P450 genes across developmental stages and castes in the red imported fire ant (Solenopsis invicta), uncovering stage- and caste-specific differential expression patterns. Genes from the CYP4, CYP6, and CYP9 families, known for metabolizing exogenous and endogenous compounds, were highly expressed in early larval stages and minim workers, underscoring their roles in supporting rapid growth, hormone metabolism, colony maintenance, and brood care. The overexpression of CYP4AA1—linked to pheromone production—in queens, female alates, and female alate pupae highlights its critical functions in reproductive dominance, social structure maintenance, and colony dynamics. Here, juvenile hormone biosynthesis genes, including CYP305A1 and CYP315A1, exhibited significant overexpression in later instar larvae and larger workers, emphasizing their roles in development and in fulfilling colony-wide physiological demands. The “Halloween genes” (CYP302A1, CYP306A1, CYP315A1, CYP307A1, and CYP314A1) and CYP18A1 demonstrated dynamic regulation across developmental stages and castes, reflecting their essential contributions to hormonal production and balance throughout S. invicta’s lifecycle. These findings offer valuable insights into the molecular and biological mechanisms driving S. invicta’s social organization, developmental transitions, physiological adaptations, and evolutionary success. They also provide a foundation for future research into the regulatory pathways governing P450 gene expression and function. Full article

Background: Epstein-Barr virus (EBV) infects approximately 95% of the global population, causing numerous malignancy-related cases annually and some autoimmune diseases. EBV-encoded gp350, gH, gL, gp42 and gB glycoproteins are identified as antigen candidates for their key role in viral entry, and nanoparticle vaccines displaying them were developed for the advantage of inducing cross-reactive B cell responses. Methods: To develop liposomes displaying nanoparticle vaccine, we synthesized liposomes to present the well-identified EBV-encoded gp350D₁₂₃ glycoprotein on their surface to imitate the viral structure, through the conjugation between N-hydroxysuccinimide (NHS) groups on the liposomes and primary amine of antigens to form stable amide bond. Then we assessed the immunogenicity of the biomimetic Lipo-gp350D₁₂₃ nanoparticle vaccine in Balb/c mice immunized experiments. Results: The results showed that the sera samples from Lipo-gp350D₁₂₃ nanoparticle vaccine immunized mice collected at weeks 8, 10 and 12 had higher titers of gp350D₁₂₃ protein-specific antibodies, compared to monomer gp350D₁₂₃ protein control, and higher titers of neutralizing antibodies to block EBV-GFP infection in AKATA cells. Meanwhile, the Lipo-gp350D₁₂₃ nanoparticle vaccine also induced higher percentage of CD8+ IFN-γ+ T cells in the spleen, but without significance in CD4+ IFN-γ+ T cells, and these isolated splenocytes showed a higher level of secreted IFN-γ. Moreover, no significant histopathological changes were observed in all vaccinated mice. Conclusions: Altogether these data demonstrated that the liposome displaying promoted the immunogenicity of antigens, and the Lipo-gp350D₁₂₃ nanoparticle vaccine candidate had potential application in blocking EBV infection. The liposome nanoparticle was a useful vector for antigen displaying to elicit effective immunity. Full article

This study investigates the competitive and cooperative relationships within urban agglomerations, specifically focusing on the Guangdong–Hong Kong–Macao Greater Bay Area (GBA). Using the Lotka–Volterra model from ecology, the research aims to analyse and predict the dynamic relationships among cities in this area. The purpose is to understand how competition and cooperation influence regional integration, and their complex economic connections. This paper employs both qualitative and quantitative methods, including time-series analysis and the application of the Lotka–Volterra model, to evaluate economic interactions and the roles of various cities or regions within the GBA. The study reveals that mutualistic, competitive, predatory, commensal, and parasitic relationships coexist among them, with core cities such as Shenzhen, Guangzhou, Hong Kong, and Macao assuming pivotal roles in shaping the overall dynamics. The findings highlight the importance of functional division, regional cooperation, and innovative collaboration to enhance sustainable development. Policy recommendations are provided to foster a balanced and integrated growth model, emphasizing inter-city cooperation, resource sharing, and avoidance of industrial homogeneity. Full article

Nitrification is the key process linking the oxidized and reduced forms of reactive nitrogen, playing an important role in the nitrogen biogeochemical cycle. Quantifying the nitrification rate and evaluating its environmental regulators in different aquatic environments at both regional and global scales has received increasing attention. However, the spatiotemporal variations in nitrification rates in coastal waters, particularly with different trophic states, remain unclear. By using the ¹⁵N-labeling technique, here, we quantified the nitrification rates under dark and light conditions in the surface waters of Shenzhen Bay and Dapeng Bay, representing eutrophic and oligotrophic environments, respectively. The nitrification rates were 2–3 orders of magnitude higher in Shenzhen Bay (eutrophic) than those in Dapeng Bay (oligotrophic). The concentrations of ammonium and total suspended matter play key roles in regulating the spatiotemporal distribution and difference in nitrification in these two coastal bays. The nitrification rate under the dark condition (0.13–49.37 nmol N L⁻¹ h⁻¹) was greater than that under light incubation (0–10.15 nmol N L⁻¹ h⁻¹), indicating light inhibition of 33–100% in the surface water. Such results imply that daily integrated nitrification based on the rates under dark incubation may have been overestimated. An environment with high turbidity is preferable for nitrification, as it reduces the damage caused by light to ammonia-oxidizing microbes. Collectively, the differences in nitrification rates further result in a distinct composition of dissolved inorganic nitrogen, with Shenzhen Bay dominated by nitrate and Dapeng Bay dominated by ammonium. Our results provide scientific references for the mitigation of nitrogen pollution in different trophic coastal bays. Full article

Intercity railways are key transportation infrastructures in the interconnection of urban agglomerations. Their stations are usually distributed based on densely populated and economically active areas, and they also play roles as regional network nodes, intra-city nodes, and functional areas. However, the academic research on the spatial development of station areas is still very limited. In particular, there is no sufficient in-depth discussion about the coordinated development mechanism of the “regional node-place” and “urban node-place” of intercity railways. Based on the case study of Guangdong–Hong Kong–Macao Greater Bay Area in China (GBA), this paper provides an in-depth analysis of the regional node development level, urban node development level, station area development level, comprehensive station area development level, and coordinated development of “regional node-place” and “urban node-place” in the GBA in 2012, 2016, 2020, and 2023 by constructing a node-place model, development index of regional nodes, development level index, and coupling coordination degree model. Findings: (1) From 2012 to 2023, the development of regional nodes, urban nodes, and places of the GBA intercity railway saw a significant improvement, with the proportion of high-value stations increasing by 13.3%, 7%, and 8.8%, respectively. Despite some improvement on the whole, the three still exhibited an unbalanced spatial distribution of “high in the middle-low in the periphery”; (2) The relative gap in development levels between “regional node-place” and “urban node-place” of intercity railways decreased by 0.159 and 0.168, respectively, showing an overall upward trend, but still showing an unbalanced spatial distribution of “high in the middle-low in the periphery”; (3) The development level of regional nodes and urban nodes is lower than that of areas and is dominated by the unbalance place and dependence types, while the unbalance node and balance types account for less; (4) The coordination of the “regional node-place” and “urban node-place” of intercity railways is gradually improved, and the stations with high coordination and high coordination levels accounts for an increased proportion from 4% to 7% and 8%, respectively. However, the coordination remains at a low level on the whole, with most sites still in the low-level coupling and lower-level coupling stages. Some stations in Guangzhou, Shenzhen, Foshan, and Dongguan have witnessed a level leap and are showing a transition towards a medium to high level of coordinated development, with the surrounding areas moving away from low-level coupling and coordination. Full article

The coastal regions of major bay areas—including San Francisco, Tokyo, New York, Guangdong–Hong Kong–Macao, and Hangzhou—are important centers of economic and social growth due to their strategic location, resources, and dynamic economies. However, the significant development disparities between the central cities and surrounding areas, as well as the challenges of climate change, highlight the need for a comprehensive assessment of their development potential. The aim of this study is to find out which cities have the strongest development potential and what the main factors influencing the results are. To address this research question, we use a combination of the Analytic Hierarchy Process (AHP) and the Entropy Weight Method (EWM) to systematically assess the development potential of 63 cities in five bay area regions and explore the mechanisms that influence it. The principal component analysis (PCA) also examines the global networking and sustainability mechanisms. The results show that Shenzhen and Shanghai lead in development potential due to strong institutional frameworks and global connectivity, but significant imbalances remain in the bay areas. Key contributors to sustainability and connectivity include air passenger traffic, public libraries, and port handling, while traditional economic metrics such as GDP growth show limited impact. These findings underscore the importance of prioritizing urban livability, resource circulation, and infrastructure over traditional economic indicators for sustainability and provide actionable insights for policy makers to promote balanced and sustainable development in bay area cities. Full article

Under the influence of factors such as extreme weather and accelerated urbanization, China has witnessed a sharp escalation in conflicts between various land-use functions, leading to a significant rise in tensions between people and land. The coordination of production, living, and ecological functions is particularly important for strengthening ecological civilization and achieving regional high-quality development. The concept of “Production–Living–Ecological” (PLE) Spaces, proposed as part of China’s ecological civilization initiative, refers to a spatial framework that integrates production spaces (land for agriculture, industry, and commerce), living spaces (land for housing, consumption, and public services), and ecological spaces (land supporting ecosystem regulation and biodiversity). Based on this perspective, this paper investigates the current situation and potential of land-use function conflicts in the Guangdong–Hong Kong–Macao Greater Bay Area in 2020. Utilizing the multi-criteria evaluation analysis method, the study develops a land-use function-evaluation model. Furthermore, the paper establishes a diagnostic model for the intensity of land-use function conflicts based on the different permutations and combinations of land unit function intensities. The land-use function conflicts are categorized into ten types and four stages. The main findings are as follows: (1) In 2020, the overall production, living, and ecological functions of Guangdong, Hong Kong, and Macao Greater Bay Area were at high, medium-high, and low levels, respectively. The land in the stable and controllable stage, the largely controllable stage, the largely out-of-control stage, and the severely out-of-control stage accounted for 39.22%, 28.73%, 25.41%, and 6.64%. The focal points of the intensity of land-use function conflicts were mainly located in Guangzhou, Foshan, Shenzhen, and Dongguan. (2) The study area was exposed to varying degrees of risk from land-use function conflicts, and the area proportion of low conflict potential area, with the proportions of low, general, higher, and high-conflict-potential areas being 47.88%, 23.43%, 22.14%, and 6.54%, respectively. (3) The primary hotspots of conflict potential were concentrated in Dongguan City and the administrative border areas of “Foshan–Zhaoqing”, “Foshan–Jiangmen”, and “Guangzhou–Zhongshan”. Full article

Background: Fluorocitrate (FC) ranging from 5 μM to 5 mM is often used as a specific metabolic inhibitor of the astrocytes to study astrocytic functions. Whether FC at such concentrations may affect neuronal metabolism and function in vivo remains unclear. Methods: We examined the effects of FC on the ATP levels and Ca²⁺ activity of the astrocytes and neurons in the motor cortices of living mice using two-photon microscopy. Results: We found that 25 μM and 250 μM of FC decreased the intracellular ATP levels and Ca²⁺ activity in the astrocytes in the motor cortex. Equally, 250 μM of FC, but not 25 μM of FC, reduced the intracellular ATP levels in the dendritic processes of the layer 5 pyramidal neurons. However, 25 μM of FC increased the neuronal Ca²⁺ activity, whereas ≥250 μM of FC decreased it. To test whether the differential effects of FC on neuronal Ca²⁺ activity reflect the direct effect of FC on the neurons or its indirect effect on the astrocytes, we used the CNO-hM3Dq chemogenetic approach to block astrocytic Ca²⁺ activity and examined the effect of FC. In the absence of astrocytic Ca²⁺ activity, 25 μM of FC still increased and ≥250 μM of FC reduced the dendritic Ca²⁺ activity of the neurons, respectively, suggesting a direct effect of 250 μM of FC on inhibiting neuronal Ca²⁺ activity. Further, 250 μM, but not 25 μM, of FC increased the size of the dendritic spines over 2 h. Conclusions: Our findings suggest that FC at high concentrations (≥250 μM) is not a specific inhibitor of astrocytic functions, as it directly affects neuronal metabolism and synaptic plasticity in vivo. Full article