Search Results (889)

Cell motility is a process central to life and is undoubtedly influenced by mechanical and chemical signals. Even so, other stimuli are also involved in controlling cell migration in vivo and in vitro. Among these, electric fields have been shown to provide a powerful and programmable cue to manipulate cell migration. There is now a clear consensus that the electromigration of membrane components represents the first response to an external electric field, which subsequently activates downstream signals responsible for controlling cell migration. Here, we focus on a specific mode of electrotaxis: frictionless, amoeboid-like migration. We used the Finite Element Method to solve an active gel model coupled with a mathematical model of the electromigration of aquaporins and investigate the effect of electric fields on ameboid migration. We demonstrate that an electric field can polarize aquaporins in a cell and, consequently, that the electromigration of aquaporins can be exploited to regulate water flux across the cell membrane. Our findings indicate that controlling these fluxes allows modulation of cell migration velocity, thereby reducing the cell’s migratory capacity. Our work provides a mechanistic framework to further study the impact of electrotaxis and to add new insights into specific modes by which electric fields modify cell motility. Full article

This study advances alkali-activated cementitious materials (AACMs) by developing a ground-granulated blast furnace slag/high-calcium fly ash (GGBS/HCFA) composite that incorporates Tuokexun desert sand and by establishing a clear linkage between activator chemistry, mix proportions, curing regimen, and microstructural mechanisms. The innovation lies in valorizing industrial by-products and desert sand while systematically optimizing the aqueous glass modulus, alkali equivalent, HCFA dosage, and curing temperature/time, and coupling mechanical testing with XRD/FTIR/SEM to reveal performance–structure relationships under thermal and chemical attacks. The optimized binder (aqueous glass modulus 1.2, alkali equivalent 6%, and HCFA 20%) achieved 28-day compressive and flexural strengths of 52.8 MPa and 9.5 MPa, respectively; increasing HCFA beyond 20% reduced compressive strength, while flexural strength peaked at 20%. The preferred curing condition was 70 °C for 12 h. Characterization showed C-(A)-S-H as the dominant gel; elevated temperature led to its decomposition, acid exposure produced abundant CaSO₄, and NaOH exposure formed N-A-S-H, each correlating with strength loss. Quantitatively, acid resistance was weaker than alkali resistance and both deteriorated with concentration: in H₂SO₄, 28-day mass loss rose from 1.22% to 4.16%, with compressive/flexural strength retention dropping to 75.2%, 71.2%, 63.4%, and 57.4% and 65.3%, 61.6%, 58.9%, and 49.5%, respectively; in NaOH (0.2/0.5/0.8/1.0 mol/L), 28-day mass change was +0.74%, +0.88%, −1.85%, and −2.06%, compressive strength declined in all cases (smallest drop 7.77% at 0.2 mol/L), and flexural strength increased at lower alkalinity, consistent with a pore-filling micro-densification effect before gel dissolution/cracking dominates. Practically, the recommended mix and curing window deliver structural-grade performance while improving high-temperature and acid/alkali resistance relative to non-optimized formulations, offering a scalable, lower-carbon route to utilize regional desert sand and industrial wastes in durable cementitious applications. Full article

Amyloid beta (Aβ) is believed to play a key role in Alzheimer’s disease (AD), whose causes, progression, diagnosis, and treatment nonetheless remain poorly understood despite decades of research. Recent studies suggest that Aβ in its various forms participates in multiple mutual feedback loops (“vicious cycles”) including tauopathy, oxidative stress, inflammation, calcium dysregulation, excitotoxicity, and probably many others, eventually leading to neurodegeneration and cognitive decline. Here, as an initial quantitative step toward modeling this vast complexity, we explore a simple kinetic model of a coupled feedback vicious cycle for Aβ buildup based on literature data for Tg2576 mice. The model is used to examine the efficacy of various hypothetical therapeutic approaches, either singly or in combination, to mitigate Aβ buildup. While our computational results support the possible efficacy of combination interventions, they also suggest caution, inasmuch as clear synergy is not found. This kinetic approach highlights the essential importance of the vicious cycle of positive feedback in a quantitative model. Full article

Background: Adeno-associated viral (AAV) vectors are the leading platform for gene therapy, but common delivery routes show limited spread to distal cortical structures, hence the utility of direct, intrathalamic infusions for broader transgene distribution. In this preliminary study, we recapitulate previous studies targeting the thalamus as a conduit to achieve cortical transgene spread and showcase novel data evaluating biodistribution of a green fluorescent protein (GFP) using cryo-fluorescence tomography (CFT). For the first time in nonhuman primates (NHPs) and coupled with magnetic resonance imaging (MRI)-guidance, we demonstrated the application of CFT as a powerful tool to map out vector distribution in the NHP brain. Methods: Briefly, a single thalamic infusion was performed in African green monkeys using ClearPoint’s navigational platform to deliver an AAV serotype 2 vector containing a GFP payload. Transgene biodistribution was assessed in the left and right hemispheres using CFT and histological analysis, respectively. Results: Infusions were successfully performed with sub-millimetric target accuracy and with minimal error, achieving ~86% thalamic coverage with the largest infusion volume. Histology confirmed the presence of the GFP transgene, with the strongest signal in the cerebral gray/white matter and internal capsule, while CFT allowed for the three-dimensional detection of the transgene starting at the site of infusion and spreading to multiple cortical regions. Conclusions: These findings suggest that by combining MRI-guided technology with CFT imaging, it is feasible to map whole-brain gene biodistribution in NHPs. This proof-of-concept study bridges the gap between cellular microscopy and MRI-guidance to provide a complete picture of disease and treatment with clinical applicability. Full article

As global urbanization accelerates in ecologically fragile regions, Nature-Based Solutions (NBS) have emerged as a critical paradigm for integrating environmental sustainability with urban resilience. Particularly in hyper-arid environments, the deployment of NBS must navigate unique climatic, hydrological, and socio-political complexities. This paper advances a conceptual framework that synthesizes the International Union for Conservation of Nature’s (IUCN) tripartite typology—protection, sustainable management, and restoration/creation—within a broader systems-oriented governance lens. By engaging with international precedents and context-specific urban dynamics, the study explores how adaptive, multiscale strategies can translate ecological principles into actionable urban design and planning practices. Through a comparative lens and grounded regional inquiry, the research identifies critical leverage points and institutional enablers necessary to operationalize NBS under desert constraints. While highlighting both the structural potential and the contextual limitations of existing initiatives in the Eastern Province of Saudi Arabia, the analysis underscores the necessity of coupling typological coherence with flexible regulatory and participatory mechanisms. Empirical findings from the Saudi case reveal persistent institutional fragmentation, heavy reliance on top-down implementation, and limited hydrological monitoring as key constraints, while also pointing to emerging governance mechanisms under Vision 2030—such as cross-sectoral coordination and pilot participatory frameworks—that can support the long-term viability of NBS in hyper-arid cities. Building on these insights, the study distills a set of strategic lessons that provide clear guidance on hydrological integration, adaptive governance, and socio-cultural legitimacy, offering a practical roadmap for operationalizing NBS in desert urban contexts. Full article

The intensified exposure to high temperature in urban areas, resulting from the combination of heat waves and the urban heat island (UHI) effect, necessitates a deeper understanding of the climate–health relationship. This knowledge directly influences the strategies employed by policy makers and urban planners in their efforts to regenerate cities and protect their population. Nature-based solutions and the widely accepted 15 min city model, characterized by a polycentric structure, should drive the implementation of effective adaptation policies, especially given the persistent delay in mitigation efforts. However, it is less clear whether current or future policies are adequately structured to broadly address the complex forms of social vulnerability. A prime example of this complexity is the demographic shift observed since the mid-20th century, characterized by a relative increase in the elderly population, and a shrinking youth demographic. While extensive literature addresses the physiological impacts of heat wave on human health, evidence regarding the neuro-psychological and cognitive implications for elderly individuals, who frequently suffer from chronic diseases, remains less comprehensive and more fragmented. The purpose of this concise review is to emphasize that crucial findings on the climate–health relationship, particularly concerning the elderly, have often been developed within disciplinary silos. The lack of comprehensive interdisciplinary integration coupled with an incomplete understanding of the full spectrum of vulnerabilities (encompassing both physiological and cognitive) may lead to urban policies that are egalitarian in principle but fail to achieve true equity in practice. This review aims to bridge this gap by highlighting the need for a more integrated approach to urban policy and regeneration. Full article

With the increasing intensity of resource development in alpine regions, numerous geotechnical engineering problems in cold regions have become increasingly prominent. In order to explore the damage and deterioration laws of rocks caused by freeze–thaw action, this paper takes the biotite granulite on the eastern slope of Yanshan Iron Mine as the research object. By analyzing the changes in mechanical and acoustic emission parameters of rock samples after freeze–thaw, and combining with existing freeze–thaw damage theories, the suitable freeze–thaw damage mechanism for this rock is further explored, and a freeze–thaw damage model for biotite granulite with low and high freeze–thaw cycles is established. The results of this study demonstrate that biotite granulite subjected to a lower number of freeze–thaw cycles exhibits significantly greater reductions in peak strength, elastic modulus, acoustic emission (AE) hit counts, cumulative ringing counts, and cumulative energy compared with specimens exposed to a higher number of cycles. As the freeze–thaw cycles increase, the formation of newly generated large-scale fractures during failure becomes progressively less pronounced, leading to a diminished resistance to deformation and a gradual increase in plastic deformation during loading. A coupled damage variable relationship was established for biotite granulite under both low and high freeze–thaw regimes based on cumulative AE ringing counts. In the early three stress stages, specimens subjected to fewer cycles exhibited fewer microcracks, with no clear spatial correlation between their distribution and the eventual fracture coalescence zones, whereas specimens exposed to a higher number of cycles showed a distinct sequential relationship between microcrack initiation sites and subsequent crack coalescence. Building upon existing freeze–thaw damage theories, the freeze–thaw damage mechanism specific to biotite granulite was further elucidated. Accordingly, a freeze–thaw damage model for low- and high-cycle conditions was developed and preliminarily validated. Full article

In southern China, the long-term irrational utilization of land resources has caused severe damage to the ecology and environment of the entire region. Serious issues such as soil degradation and water erosion have led to the decline of soil quality and productivity. In this study, the spatial distribution characteristics of soil carbon, nitrogen, and phosphorus in Zhuxi watershed, Changting County, southern China, were analyzed by coupling geostatistics with GIS. The analysis generated several important results: (1) The concentrations of soil organic matter (OM), alkali-hydrolyzable nitrogen (AN), and available phosphorus (AP) are at moderate levels, and AP exhibits local enrichment in the downstream farmland, while the concentrations of total nitrogen (TN) and total phosphorus (TP) remain at low levels. (2) The optimal theoretical model for AN is an exponential model, while other nutrients follow spherical models. Except for AP, which has a nugget effect exceeding 75%, the nugget effects of other nutrients range between 25% and 75%, indicating that their spatial distribution is moderately correlated. According to Kriging interpolation results, the distribution of OM, TN, and AN shows a clear trend of decreasing from northeast to southwest, followed by a gradual increase, which is generally consistent with the direction of rivers. The trends of TP and AP are more irregular, generally decreasing from downstream to upstream. (3) OM, TN, and AN exhibit a negative correlation with the degree of soil erosion, indicating that soil erosion is associated with the loss of carbon and nitrogen nutrients. However, the impact on phosphorus is relatively insignificant. Full article

Grassland aboveground biomass (AGB) serves as a critical indicator of ecosystem productivity and carbon cycling, playing a pivotal role in ecosystem functioning. The advances in hyperspectral and terrestrial Light Detection and Ranging (LiDAR) data have provided new opportunities for grassland AGB monitoring, but current research remains predominantly focused on data-driven machine learning models. The black-box nature of such approaches resulted in a lack of clear interpretation regarding the coupling relationships between these two data types in grassland AGB estimation. For grassland aboveground fresh biomass, the theoretical estimation can be decomposed into either the product of planar density (PD) and plot area or the product of stereoscopic density (SD) and grassland community volume. Based on this theory, our study developed a semi-mechanistic remote sensing model for grassland AGB estimation by integrating hyperspectral-derived biomass density with extracted structural parameters from terrestrial LiDAR. Initially, we built hyperspectral estimation models for both PD and SD of grassland fresh AGB using PLSR. Subsequently, by integrating the inversion results with grassland quadrat area and community volume measurements, respectively, we achieved quadrat-scale remote sensing estimation of grassland AGB. Finally, we conducted comparative accuracy assessments of both methods across different phenological stages to evaluate their performance differences. Our results demonstrated that SD, which incorporated structural features, could be more precisely estimated (R² = 0.90, nRMSE = 7.92%, Bias% = 0.01%) based on hyperspectral data compared to PD (R² = 0.79, nRMSE = 10.19%, Bias% = −7.25%), with significant differences observed in their respective responsive spectral bands. PD showed greater sensitivity to shortwave infrared regions, while SD exhibited stronger associations with visible, red-edge, and near-infrared bands. Although both methods achieved comparable overall AGB estimation accuracy (PD-based: R² = 0.79, nRMSE = 10.19%, Bias% = −7.25%; SD-based: R² = 0.82, nRMSE = 10.58%, Bias% = 1.86%), the SD-based approach effectively mitigated the underestimation of high biomass values caused by spectral saturation effects and also demonstrated superior and more stable performance across different growth periods (R² > 0.6). This work provided concrete physical meaning to the integration of hyperspectral and LiDAR data for grassland AGB monitoring and further suggested the potential of multi-source remote sensing data fusion in estimating grassland AGB. The findings offered theoretical foundations for developing large-scale grassland AGB monitoring models using airborne and spaceborne remote sensing platforms. Full article

The increasing demand for functional beverages sparked greater interest in health-promoting craft drinks, highlighting the need to optimize production parameters and assess their stability. This study aimed to develop, optimize, and characterize a grape juice-flavored naturally carbonated water kefir, evaluating its sensory qualities, physicochemical and microbiological stability. Fermentation conditions (F1) were optimized using Central Composite Rotational Design, leading to the selection of 24 h at 30 °C with (6.5% w/v) brown sugar, ensuring efficient pH reduction to safe levels. Sensory analysis selected grape juice as the flavoring agent, and a mixture design coupled with the desirability function determined the optimal formulation as 50% kefired water, 46.4% grape juice, and 3.6% water, resulting in high overall sensory desirability. During 42 days of refrigerated storage (4 °C), the beverage exhibited progressive sugar consumption from residual metabolic activity, a dynamic antioxidant profile characterized by increases in total phenolic compounds and FRAP activity, stability in ABTS activity, and decline in DPPH activity. Lactic acid bacteria counts remained stable during storage, while acetic acid bacteria and yeast populations decreased. Furthermore, pH (~3.30) and alcohol content (~1.86 °GL) remained stable, although the latter requires clear labeling in compliance with regulations for similar fermented beverages. Full article

The mutagenic potential of coffee by-products, including Coffea leaves, blossoms, cherries, and silverskin, was studied using thin-layer chromatography (TLC) coupled with the recent planar Ames bioassay via pH indicator endpoint. The 2LabsToGo-Eco allowed for the separation and detection of mutagens in complex samples. Hot water was the most effective extraction solvent in terms of yield and closely simulated the typical human consumption of coffee by-products. Separation was performed on TLC plates with a mixture of ethyl acetate, n-propanol, and water, followed by bioassay detection. The positive control 4-nitroquinoline 1-oxide exhibited clear mutagenic responses, confirming the proper bioassay performance. In the Ames bioautogram, none of the tested coffee by-products showed mutagenic zones, suggesting the absence of strongly acting, acute mutagens under the applied test conditions; however, given the only 5 h short incubation and the use of TA98 strain only, a longer incubation time and testing with additional Salmonella strains is recommended. The results provide new safety data for Coffea leaves and blossoms and are consistent with some previous studies demonstrating the safety of coffee by-products. However, further improvements in the sensitivity and selectivity of the planar Ames bioassay are demanded, and further in vivo and long-term safety studies are recommended. Considering natural variability, the different uses of pesticides and treatments, and the fluctuating supply chains, coffee by-products may differ highly. The planar bioassay technology using the affordable 2LabsToGo-Eco is a powerful toxicological screening option for the coffee industry, considering the increasing interest in utilizing coffee by-products. Full article

Accurate and robust runoff simulation is crucial for effective reservoir regulation. Although it is clear that enhancing runoff simulation or optimizing reservoir operation strategies can improve the management of hydropower resources, the specific impact of enhanced simulated runoff on reservoir operation under optimized regulation has not been thoroughly examined. To investigate how high-precision runoff simulation influences reservoir performance, this study proposed a unidirectional coupling framework of the distributed hydrological model CREST and the LSTM model, incorporating the seasonal characteristics of the satellite-based precipitation product CHIRPS. The influence of simulated runoff on hydropower generation was examined from two perspectives: metrics’ accuracy and process-based analysis. The results showed that, following the unidirectional coupling, the Coupling scheme achieved improvements in NSE and R² by 6% and 4%, respectively, while RMSE decreased by 24%. Additionally, it accurately captured the seasonal variations and amplitude of runoff at the annual scale, and was able to reliably detect the periodic signals within runoff across various scales. After reservoir optimization operation, the simulated runoff derived from the Coupling scheme produced hydropower and surplus water values close to those obtained from observed runoff, with errors of 1.09% and −21.64%, respectively. Moreover, the Coupling scheme corrected the prominent peaks in hydropower generation seen in the CREST model across multiple periods, demonstrating a stronger capability for temporal runoff simulation closely aligned with observed runoff in terms of temporal structure. Full article

In deep-sea mining operations, rigid risers operate in a complex and uncertain ocean environment where vessel–riser interactions present significant structural challenges. This study develops a coupled dynamic modeling framework that integrates vessel motions and environmental loads to evaluate the probabilistic risk of riser failure. Using frequency-domain RAOs derived from AQWA and time-domain simulations in OrcaFlex 11.0, we analyze the riser’s effective tension, bending moment, and von Mises stress under a range of wave heights, periods, and directions, as well as varying current and wind speeds. A Monte Carlo simulation framework based on Latin hypercube sampling is used to generate 10,000 sea state scenarios. The response distributions are approximated using probability density functions to assess structural reliability, and global sensitivity is evaluated using a Sobol-based approach. Results show that the wave height and period are the primary drivers of riser dynamic response, both with sensitivity indices exceeding 0.7. Transverse wave directions exert stronger dynamic excitation, and the current speed notably affects the bending moment (sensitivity index = 0.111). The proposed methodology unifies a coupled time-domain simulation, environmental uncertainty analysis, and reliability assessment, enabling clear identification of dominant factors and distribution patterns of extreme riser responses. Additionally, the workflow offers practical guidance on key monitoring targets, alarm thresholds, and safe operation to support design and real-time decision-making. Full article

With the rapid development of China’s economy, the number and scale of infrastructure projects in energy, water conservancy, and transportation have expanded significantly. Anchoring technology has been widely applied, resulting in the formation of numerous rock slope–anchoring systems. This study proposes a novel method for evaluating the stability of rock slope–anchoring systems by introducing catastrophe theory into the stability assessment framework. Based on the characteristics of the rock slope–anchoring system and its stability-influencing factors, a hierarchical analytic structure for catastrophe-level evaluation is constructed, and relevant indicator data are collected. Catastrophe models are selected according to the identified state and control variables, and catastrophe levels are computed to establish a sample dataset. The relationship between catastrophe levels and the stability coefficients of rock slope–anchoring systems is verified to define stability grade intervals. Stability evaluation is then performed by calculating the catastrophe level of each system. The results indicate that: (1) the proposed method effectively considers the influence of multiple factors on the stability of rock slope–anchoring systems, ensuring high accuracy in the evaluation. (2) The method allows for the automatic quantification of the relative importance of indicators within the same hierarchy, reducing subjectivity caused by manual weighting. (3) By standardizing state variables and computing catastrophe levels, the method couples qualitative descriptions with mechanical parameters, enhancing the objectivity of the assessment. (4) The stability evaluation method for rock slope–anchorage systems based on mathematical catastrophe theory determines system stability through catastrophe-order analysis, featuring a concise process and clear results. It enables rapid evaluation of the stability of similar rock slope–anchorage systems and offers high efficiency for cluster assessments. Full article

Global climate change has intensified urban heat exposure risks due to extreme heat events, posing significant health threats, particularly to socially vulnerable groups such as the elderly and children. However, the spatial allocation of urban public cooling resources exhibits heterogeneity, leading to insufficient or mismatched provision of cooling facilities in high heat exposure areas. Taking the central urban area of Guangzhou, China as an example, we employ the hazard–exposure–vulnerability (HEV) framework to evaluate a composite heat risk index (HRI). Using a coupling coordination degree and development coordination coefficient, we identify the matching status and temporal dynamic between heat risk and facility supply across 2010 and 2020. The results indicate that (1) HRI generally exhibits high-value clustering in the core areas of the old city, while peripheral areas show relatively lower levels; (2) the coupling coordination degree (CCD) exhibits clear spatial clustering characteristics, and highly coordinated streets are mostly concentrated in old city areas, whereas newly developed and peripheral districts generally show low coordination; and (3) from 2010 to 2020, cooling facility development in old city districts was generally proactive, while newly developed and peripheral areas exhibited slower progress relative to increasing heat risk. This study highlights the issue of adaptive imbalance in the allocation of cooling resources concerning vulnerable populations, providing guidance for future urban planning. Full article