Search Results (200)

Urban mangroves are increasingly recognized for their important blue-carbon functions, yet their long-term aboveground carbon dynamics under climate extremes and human disturbances remain poorly understood. Here, we developed an integrated framework that combines multi-source satellite observations, field survey and LiDAR-constrained modeling to reconstruct annual species composition, canopy structure, and aboveground carbon dynamics from 1990 to 2022 in Shenzhen Bay, which is the only mangrove ecosystem within a megacity in China. Total aboveground carbon increased from 1820 (95% CI: 1386–2199) Mg C in 1990 to 6006 (95% CI: 5280–6618) Mg C in 2022, with habitat expansion accounting for most of the increase. Aboveground carbon accumulation was affected by coastal reclamation, estuarine engineering, and management-driven removal of introduced stands. Species composition emerged as a key determinant of ecosystem response to disturbance and long-term carbon dynamics. Native mangroves remained dominant and exhibited relatively stable canopy greenness during the 2008 extreme cold event. But the introduced Sonneratia apetala experienced a 42.9% drop in greenness and then took about five years to return to the level before the disturbance. By linking long-term changes in species composition, canopy structure, and aboveground carbon storage, this study provides a transferable foundation for monitoring urban blue-carbon ecosystems and evaluating the long-term consequences of disturbance, restoration, and management under accelerating urbanization and climate change. Full article

Dual-motor electric drive axles (e-axles) can realize basic torque vectoring through motor-torque allocation. However, without an inter-wheel power-transfer path, they still face structural limitations under motor torque–speed envelopes and severe left–right adhesion asymmetry. To address this issue, this paper proposes a reconfigurable dual-motor e-axle based on fixed-carrier compound planetary gear trains and two cross-axle clutches. By switching between controlled-slip and lock-coupled states, the proposed topology creates a switchable inter-wheel power-transfer path. As a result, it enhances yaw-rate regulation capability under high-adhesion conditions and improves escape capability under severe adhesion asymmetry. A unified kinematic–static analytical framework is established to derive closed-form capability boundaries and compact structural indices for parameter matching. Vehicle-level co-simulation on a representative rear-wheel-drive platform is then carried out for validation. Under severe split-$\mu$ conditions, the peak high-adhesion wheel torque increases from 241.72 to 695.57 N·m, and the escape time decreases from 0.43 to 0.19 s. In a representative high-adhesion step-steer case, the mean yaw-rate tracking error is reduced from 6.75 to 0.20 deg/s, while the mean differential wheel torque reaches 1.83 times that of the baseline mode. The other high-adhesion cases show the same trend. These results verify the vehicle-dynamics significance and engineering feasibility of the proposed architecture. Full article

With the continuous expansion of building scale and increasingly complex functions, pedestrian congestion within buildings has become increasingly prominent. To identify high-utilization spaces during the architectural design stage, so as to optimize the design at the source and effectively alleviate the risk of oversaturated spatial flow in super high-rise buildings, transportation hubs and other complex buildings, this paper investigates spatial flow estimation methods in the architectural design phase. First, based on detailed data from microscopic pedestrian simulation in buildings, this study conducts an in-depth analysis of the factors influencing spatial flow from the perspectives of spatial structure and pedestrian demand. Then, by incorporating the visual integration degree from space syntax and the proposed Origin-Destination (OD) influence range definition method that accounts for obstacle detours, a spatial utilization intensity index integrating both factors is developed. Furthermore, regression analysis is employed to achieve spatial flow estimation based on the constructed spatial utilization intensity index. Finally, taking the basement 1 floor of the Shenzhen Bay Super Headquarters Base C Tower connected with the metro as an example, the effectiveness of the proposed method is verified. The results show that the MAPE is 26%. This study provides an effective estimation method for the prediction of spatial flow in the architectural design stage. Full article

Substituted p-phenylenediamines (PPDs) and their quinone derivatives (PPD-Qs) are emerging contaminants associated with tire-related antioxidants and antiozonants and have raised increasing concern because of their potential environmental effects. However, information on their occurrence in estuarine systems, particularly their combined distribution in water and sediment, remains limited in the Pearl River Estuary. In this study, 30 water samples and five sediment samples collected from the Pearl River Estuary were analyzed for selected PPDs and PPD-Qs. Four target compounds were detected in water, whereas nine were found in sediments, indicating broader occurrence in the sediment phase. The total concentration of PPDs ranged from below the detection limit to 17.6 ng/L in water and from 0.140 to 1.37 ng/g in sediments. In water, 6PPD and 6PPD-Q showed relatively high detection frequencies, while elevated IPPD concentrations were observed at several sites near urbanized coastal areas. In sediments, the highest ΣPPDs level was recorded in Shenzhen Bay. The observed spatial patterns suggest that mixed anthropogenic inputs may influence the occurrence of these compounds in the estuary, although direct source attribution requires further investigation. Overall, this study provides preliminary baseline information on the occurrence and phase-specific distribution of PPDs and PPD-Qs in the Pearl River Estuary and supports future investigations into their environmental fate and ecological relevance. Full article

To elucidate the sources and spatial variations in organic matter in surface sediments from Lingdingyang of the Pearl River Estuary, 18 surface sediment samples were collected and analyzed for obtaining total organic carbon (TOC), total nitrogen (TN), atomic TOC/TN ratio (C/N_atom), stable carbon and nitrogen isotopes (δ¹³C, δ¹⁵N), and glycerol dialkyl glycerol tetraethers (GDGTs). A three-endmember framework was constructed using the BIT and δ¹³C to constrain the sources of the organic matter. The results showed a significant positive correlation between TOC and TN, with relatively higher values in Jiaoyi Bay and western Lingdingyang, lower values in eastern Lingdingyang, and intermediate values in Shenzhen Bay. The C/N_atom, δ¹³C, and δ¹⁵N results revealed that the sedimentary organic matter in the study area exhibits mixed-source characteristics, influenced by soil, C₃ plants, and marine autochthonous organic matter. Among the subregions, Jiaoyi Bay is more strongly influenced by terrestrial inputs, while Shenzhen Bay receives relatively higher contributions from marine autochthonous organic matter. The GDGTs results showed that Jiaoyi Bay is characterized by elevated abundances of both brGDGTs and isoGDGTs, whereas isoGDGTs were also relatively enriched in Shenzhen Bay. brGDGTs exhibited a significant negative correlation with δ¹³C, whereas BIT showed no significant correlation with either brGDGTs or δ¹³C, indicating that BIT cannot be simply regarded as a unique proxy for soil input, but rather reflects the combined effects of in situ production, changes in archaeal lipids, and sedimentary preservation. The three-endmember model further revealed significant spatial variations in the sources of organic matter in surface sediments from Lingdingyang. Overall, the combined use of multiple proxies is more effective than any single proxy in revealing the sources and spatial differentiation of sedimentary organic matter in this subtropical, complex estuarine environment. Full article

The hERG potassium channel is critical for cardiac ventricular repolarization and a core target in pre-clinical drug safety screening. A robust, stable cell line with uniform, high hERG expression is essential for high-throughput assessments. In this study, we established a functional stable HEK293T cell line with high hERG expression. The hERG gene was subcloned into Lenti-HA-hERG-P2A-EGFP plasmid, in which GFP serves as a selection marker via a P2A self-cleaving peptide. GFP-positive monoclonal cells were isolated by fluorescence-activated cell sorting (FACS). Confocal imaging confirmed that hERG localized predominantly to the cell membrane, consistent with its physiological role. Manual patch-clamp revealed canonical hERG current properties: a small, stable current during depolarization to 20 mV, followed by a large outward tail current upon repolarization to −40 mV-a hallmark of hERG channel gating. Automated patch-clamp (APC)-based current profiling showed 93.5% of stable hERG cells exhibited peak tail currents > 50 pA (87% > 100 pA, with 49.5% > 400 pA), whereas 100% of blank HEK293T cells showed peak tail currents < 50 pA. Pharmacological validation with E-4031 demonstrated concentration-dependent inhibition of hERG currents, with an IC₅₀ of 29.8 nM, which is consistent with literature-reported values. The stable hERG-expressing HEK293T cell line developed here exhibits consistent hERG expression, canonical channel function, and physiological sensitivity to hERG blockers. When paired with high-throughput APC systems, this cell model provides a robust, standardized platform for pre-clinical drug-induced hERG inhibition evaluation, aiding early detection of long QT syndrome risks and safer drug development. Full article

Pertussis toxin (PTx) is a major virulence factor of Bordetella pertussis and an AB5-type exotoxin that disrupts host signaling. Its enzymatic A subunit ADP-ribosylates the α-subunit of inhibitory G proteins (Gα_i), preventing them from mediating receptor-induced inhibition of adenylyl cyclase (AC). This leads to unrestrained cAMP accumulation in host cells, a canonical mechanism underlying many pertussis disease manifestations. PTx works in concert with the bacterium’s adenylate cyclase toxin (ACT) to subvert immune defenses and establish infection. Interestingly, PTx exerts both cAMP-dependent and cAMP-independent effects. In addition to the well-known cAMP-mediated pathway, PTx’s B oligomer can engage host cell surface receptors to trigger signaling cascades independent of the A subunit’s catalytic activity. Such B oligomer-mediated pathways modulate cellular responses in the absence of ADP-ribosylation. This review provides a comprehensive analysis of PTx’s dual functionality, distinguishing its G_i protein-dependent elevation of cAMP from the noncanonical activities of the B oligomer. It also highlights how disruption of constitutive G_i signaling and the interplay between PTx and ACT shape host–pathogen interaction in pertussis pathogenesis. Full article

Respiratory syncytial virus (RSV) poses a significant global health challenge, particularly affecting infants, the elderly, and immunocompromised individuals. Despite recent progress in the development of vaccines and monoclonal antibodies, effective antiviral therapies remain limited. To advance the discovery of antiviral drugs, we have developed a dual-reporter RSV minigenome system, providing a safe and robust platform for antiviral evaluation. This system incorporates NanoLuc luciferase and superfolder GFP (sfGFP) linked by a self-cleaving P2A peptide, allowing for the simultaneous detection of orthogonal signals. Validation with L polymerase inhibitors confirmed the system’s reliability for screening small-molecule inhibitors. The linear correlation observed between the reporter signals enhances the assay’s reliability for antiviral assessment. This dual-reporter minigenome system advances targeted therapeutic strategies against RSV. Full article

Despite the aesthetic potential of free-form envelopes in large-scale public buildings, geometric interlacing complexity, ambiguous façade boundaries, and constructability translation gaps persist as systemic barriers. This study addresses these challenges through a Design Science Research (DSR) approach, developing a rule-based digital twin methodology that maintains parametric intelligence across the building life cycle. Implemented via a five-layer integrated framework, i.e., geometric, parametric, BIM, coordination, and fabrication, the methodology was validated through a revelatory case study of the Shenzhen Bay Culture Plaza. Results demonstrate 91.2% clash resolution prior to construction, 20.3 million RMB in cost savings (10.8% reduction), and 35.4% schedule compression, while preserving rule-based relationships into operational facility management. The study advances BIM theory by operationalizing life-cycle digital twins for non-standard geometries, offering a replicable framework for future special-shaped construction projects. Full article

Rapid urbanisation in coastal megacities intensifies coupled climate and water-related challenges, including heat stress, ventilation deficits, and increasing sensitivity to hydro-climatic extremes. Urban morphology plays a critical role in regulating these climate–water interactions by shaping airflow, surface heat exchange, and the spatial organisation of green–blue infrastructures. This study develops a Local Climate Zone (LCZ)-conditioned generative modelling framework based on a Conditional Pix2Pix Generative Adversarial Network, using paired LCZ classification maps and urban morphology data derived from six representative cities in the Guangdong–Hong Kong–Macao Greater Bay Area: Guangzhou, Shenzhen, Hong Kong, Macao, Zhuhai, and Dongguan. By integrating remote sensing–derived LCZ classifications with urban morphology data, the proposed framework learns spatial patterns associated with key morphology-related predictors, including building density and compactness, height-related structural intensity, open-space distribution, and the continuity of green–blue and ventilation corridors. The model demonstrates robust performance (SSIM = 0.74, R² = 0.81, PSNR = 15.3 dB) and strong cross-city transferability, accurately reproducing density transitions, ventilation corridors, and green–blue spatial structures relevant to coastal climate and water adaptation. The results highlight the potential of LCZ-informed generative modelling as a scalable decision-support tool for climate–water adaptive urban planning, enabling rapid exploration of morphology configurations that support heat mitigation, ventilation enhancement, and resilient coastal transformation. Full article

The endolysosomal system plays a pivotal role in cellular function. Before reaching lysosomes for degradation, the endocytosed cargoes are sorted at various stages of endosomal trafficking for recycling and/or rerouting. The proper execution of these processes depends on tightly regulated ion fluxes across endolysosomal membranes. Recent studies have demonstrated the importance of two-pore channels (TPCs), including TPC1 and TPC2, in endolysosomal trafficking. These channels are expressed in the membranes of distinct populations of endosomes and lysosomes, where they respond to nicotinic acid adenine dinucleotide phosphate (NAADP) and phosphatidylinositol 3,5-bisphosphate [PI(3,5)P₂] to conduct Ca²⁺ and Na⁺ release from these acidic organelles. Here, we discuss the potential implications of Ca²⁺ and Na⁺ fluxes mediated by TPCs across endolysosomal membranes in the physiological and pathophysiological functions of these organellar channels. Full article

The Shenzhen–Zhongshan Link is a key cross-sea corridor in the Guangdong–Hong Kong–Macao Greater Bay Area. As a representative ultra-wide cross-section undersea tunnel, it exhibits smoke spread behaviors that differ fundamentally from those of traditional road tunnels. In particular, the radial flow region of fire smoke is more pronounced, resulting in substantial lateral variations in smoke dynamics parameters. These characteristics render classical one-dimensional ceiling jet temperature rise theories insufficient for capturing the multidimensional thermal behavior in such geometries. In this study, the immersed-tunnel section of the Shenzhen–Zhongshan Link was investigated through a combination of full-scale fire experiments and Fire Dynamics Simulator (FDS) simulations. The longitudinal attenuation and lateral distribution characteristics of hot smoke temperature rise during spread in an ultra-wide tunnel were systematically obtained. Based on a simplified one-dimensional ceiling jet concept, differences in hot smoke diffusion distance were employed to characterize the lateral temperature rise ratio at any longitudinal location, from which a lateral distribution model was developed. The classical one-dimensional average temperature rise decay model was further reformulated to derive a modified longitudinal decay model applicable to the tunnel centerline of ultra-wide cross-sections. By integrating these characteristic models, a two-dimensional longitudinal prediction framework for hot smoke temperature rise in ultra-wide tunnels was established. Validation against full-scale fire experiments demonstrates that the proposed model can predict the two-dimensional thermal field with an accuracy within 25%. The findings of this study provide a theoretical basis for fire scenario reconstruction in the Shenzhen–Zhongshan undersea tunnel and offer a technical foundation for optimizing emergency ventilation strategies during fire incidents. Full article

Chlorophyll-a (Chl-a) concentration serves as a crucial indicator for assessing phytoplankton biomass and marine ecological health. This study investigated the spatiotemporal characteristics and influencing factors of Chl-a in Shenzhen’s coastal waters using high-frequency monitoring data from 13 buoys deployed from January 2023 to January 2024. The research methodology incorporated comprehensive statistical analyses, including correlation analysis to identify relationships between Chl-a and environmental parameters and a linear mixed model, as well as stepwise regression analysis to determine the dominant factors controlling Chl-a variability across different sea areas. Results revealed distinct spatiotemporal patterns: seasonal Chl-a concentrations ranked as summer > autumn > winter > spring. Spatially, western waters (Pearl River Estuary and Shenzhen Bay) exhibited elevated levels from winter to summer, whereas the eastern Daya Bay peaked in autumn. Mechanistically, regional drivers diverged significantly. River runoff dominated Chl-a variability in the Pearl River Estuary. Temperature and runoff co-regulated dynamics in Shenzhen Bay. Wind-driven mixing and nutrients were the primary controls in Daya Bay, while oligotrophic conditions maintained low levels in Mirs Bay. Salinity and temperature were universal regulators, but nutrient limitations were region-specific, with phosphorus limitation in Shenzhen Bay and nitrogen limitation in Mirs Bay. The high-frequency buoy data effectively captured complex spatiotemporal variability, providing valuable insights for developing targeted management strategies to mitigate red tide risks and improve water quality in these coastal ecosystems. Full article

3,4-dihydroquinolone and its derivatives are structural motifs found in diverse pharmacologically active compounds. Direct oxidation of tetrahydroquinolines represents the most efficient synthetic route to 3,4-dihydroquinolone. However, the reaction conditions reported in previous studies were either relatively harsh or complex. We also attempted previously reported photocatalytic oxidation methods for the α-carbonylation of amines, but these approaches failed to efficiently produce 3,4-dihydroquinolone. Herein, we present an efficient photocatalytic oxidation methodology facilitated by our in-house high-throughput microfluidic system, which can be carried out under mild conditions with a short reaction time. Moreover, a new reaction mechanism, in which the organic base DBU serves a dual role as both an electron donor and a hydrogen atom transfer (HAT) mediator, is proposed and supported by DFT calculations. Full article

Understanding how long-term local climate zone (LCZ) dynamics interact with rapid urbanization and land surface temperature (LST) changes is essential for sustainable planning in megaregion-scale urban clusters. In this paper, we propose a multi-feature local sample transfer method to obtain LCZ maps from 2000 to 2020 in the Guangdong–Hong Kong–Macao Greater Bay Area (GBA) and then analyze spatiotemporal changes in LCZs and their impacts on surface thermal environments. Results show the following: (1) The proposed multi-feature local sample transfer approach significantly improves the efficiency of long-term LCZ mapping by greatly reducing the effort required for sample acquisition. (2) The built types (LCZ1–10) increased by 1.34% overall, with large low-rise (LCZ8) showing the greatest expansion (4.72%). The compact low-rise (LCZ3) was the only built type to decline, decreasing by 2.02%. (3) Urbanization has produced a contiguous warming core that expands outward from the central metropolitan zones, thereby promoting the UHI coalescence. (4) Dense trees (LCZA) and large low-rise (LCZ8) exerted the strongest influence on LST. Large low-rise (LCZ8) consistently exhibited the highest warming contribution in Foshan, Zhongshan, and Dongguan. In coastal cities including Shenzhen, Hong Kong, and Macao, the largest LST increases occurred when water (LCZG) areas were converted to bare rock or paved (LCZE) or cs (LCZ1–10). Overall, the results highlight the strong coupling between urbanization and surface heating, providing critical insights for urban climate adaptation and integrated land-use planning in rapidly urbanizing megaregions. Full article