Search Results (1,002)

Closed-loop geothermal systems (CLGSs) avoid groundwater production and offer stable deep heat supply, but their long-term performance hinges on reliable coupling between the wellbore, the near-well interface and the surrounding formation. Using the D22 well in the Xiongan New Area (deep carbonate reservoir), we built a three-domain thermo-hydraulic framework that updates CO₂ properties with temperature and pressure and explicitly accounts for wellbore-formation thermal resistance. Two geometries (U-tube and single-well coaxial) and two working fluids (CO₂ and water) were compared and optimized under field constraints. With the coaxial configuration, CO₂ delivers an average thermal power of 186.3 kW, exceeding that of water by 44.9%, while the fraction of wellbore heat loss drops by 3–5%. Under field-matched conditions, the predicted outlet temperature (76.8 °C) agrees with the measured value (77.2 °C) within 0.52%, confirming the value of field calibration for parameter transferability. Long-term simulations indicate that after 30 years of continuous operation the outlet temperature decline remains <8 °C for CO₂, outperforming water and implying better reservoir utilization and supply stability. Sensitivity and Pareto analyses identify a practical operating window, i.e., flow velocity of 0.9–1.1 m s⁻¹ and depth of 3000–3500 m, favoring the single-well coaxial + CO₂ scheme. These results show how field-calibrated modeling narrows uncertainty and yields implementable guidance on geometry, operating conditions, and wellbore insulation strategy. This study provides quantitative evidence that CO₂-CLGSs in deep carbonate formations can simultaneously increase thermal output and limit long-term decline, supporting near-term engineering deployment. Full article

Background/Objectives: Antimicrobial resistance (AMR) in Klebsiella pneumoniae poses a serious threat to healthcare, especially in sub-Saharan Africa (SSA). To complement AMR infection control in Kenya, here, clinical and environmental genomes were investigated to determine the potential roles prophages play in K. pneumoniae pathogenicity. Methods: Prophages were extracted from 89 Kenyan K. pneumoniae genomes. The intact prophages were examined for virulence genes carriage, and their phylogenetic relationships were established. Results: Eighty-eight (~99%) of the genomes encode at least a single prophage, and there is an average of four prophages and 2.8% contributory genomes per bacterial strain. From the 364 prophages identified, 250 (68.7%) were intact, while 58 (15.9%) and 57 (15.7%) were questionable and incomplete, respectively. Approximately, 30% of the intact prophages encode 38 virulence genes that are linked to iron uptake (8), regulation (6), adherence (5), secretion system (4), antiphagocytosis (4), autotransporter (4), immune modulation (3), invasion (2), toxin (1) and cell surface/capsule (1). Phylogenetic analyses revealed three distinct clades of the intact prophages irrespective of their hosts, sources and locations, which support the plasticity of the genomes and potential to mediate horizontal gene transfer. Conclusions: This study provides first evidence showing the diverse prophages that are encoded in K. pneumoniae from SSA with particular focus on Kenyan strains. This also shows the potential roles these prophages play in the pathogenicity and success of K. pneumoniae and could improve knowledge and complement control strategies in the region and across the globe. Further work is needed to show the expression of these genes through lysogenisation. Full article

A two-year field study was performed to evaluate the cadmium (Cd) phytoremediation potential of two hyperaccumulators, Sedum alfredii (S.A.) and Sedum plumbizincicola (S.P.), in contaminated farmland. Biomass and Cd uptake in both species followed logistic growth models. S.A. reached maturity about 20 days earlier than S.P., with optimal harvest timing at the early late-flowering stage (early–mid May), compared to the full late-flowering stage (early June) for S.P. The primary Cd-accumulating organs were stems and flowers in S.A. and leaves and stems in S.P. Under identical conditions, S.P. exhibited higher theoretical biomass, Cd content, bioconcentration factor (BCF), and Cd uptake, supported by transcriptomic data showing upregulation of metal transporter and stress-related genes under Cd exposure. However, S.P. demonstrated greater environmental sensitivity and lower stress resistance, resulting in more variable real-world remediation efficiency than S.A. It is recommended to harvest at flowering stages, enhance biomass in key Cd-accumulating tissues, and select species based on local conditions. Future work should aim to breed Sedum varieties with greater biomass, Cd accumulation capacity, and stress tolerance. This study provides actionable insights for optimizing the timing and species selection in Cd phytoremediation. Full article

With the widespread deployment of high-voltage and ultra-high-voltage transmission lines, composite insulators play a vital role in modern power systems. However, prolonged service leads to material aging, and the current lack of standardized, quantitative methods for evaluating silicone rubber degradation poses significant challenges for condition-based maintenance. To address this measurement gap, we propose a novel aging assessment framework that integrates Fourier Transform Infrared (FTIR) spectroscopy with a measurement-oriented ensemble learning model. FTIR is utilized to extract absorbance peak areas from multiple aging-sensitive functional groups, forming the basis for quantitative evaluation. This work establishes a measurement-driven framework for aging assessment, supported by information-theoretic feature selection to enhance spectral relevance. The dataset is augmented to 4847 samples using linear interpolation to improve generalization. The proposed model employs k-nearest neighbor (KNN), Support Vector Machine (SVM), Random Forest (RF), and Gradient-Boosting Decision Tree (GBDT) within a two-tier ensemble architecture featuring dynamic weight allocation and a class-balanced weighted cross-entropy loss. The model achieves 96.17% accuracy and demonstrates strong robustness under noise and anomaly disturbances. SHAP analysis confirms the resistance to overfitting. This work provides a scalable and reliable method for assessing silicone rubber aging, contributing to the development of intelligent, data-driven diagnostic tools for electrical insulation systems. Full article

As diversity, equity, and inclusion (DEI) efforts in higher education face increasing scrutiny and political backlash, institutions across the United States are reexamining, reframing, and in many cases, dismantling long-standing commitments to equity work. This collaborative autoethnographic study explores the lived experiences of four Black educators, three actively pursuing doctoral degrees while serving as student affairs administrators and one faculty member who holds administrative responsibilities. Drawing on role theory, we introduce the concept Dual Combat Strain, a compounded and inseparable form of role strain that emerges when both academic and professional identities are simultaneously contested, surveilled, and constrained. The findings highlight the tensions, strategies, and forms of resistance that these educators employ to persist, advocate, mentor, and build coalitions within an increasingly volatile higher education landscape. By naming and framing Dual Combat Strain, this study extends role strain theory and applies it to the interconnected academic and professional realities of educators and offers actionable insights to support educators committed to equity based work. Full article

Deep soft rock roadways at about 1 km depth experience significant deformation due to concentrated stress ahead of the working face and dynamic loads from the hard roof layer. We propose an integrated control method that couples directional roof cutting, which interrupts stress transfer with constant resistance, and large deformation cable reinforcement to accommodate residual movement. The calibrated FLAC3D model indicates a lower front of face stress and a diminished cyclic build up of elastic strain energy in the roof, which reduces roadway convergence. Field data from Face 13403 corroborate the method’s effectiveness: the average hydraulic support load on the roof cutting side was 20.3 MPa, which is 30.1% lower than on the non-cutting side; deformation stabilized about 320 m behind the face; the final roof to floor and rib to rib closures were 1.10 m and 1.47 m; and the entry remained fit for the next panel. These results indicate that coupling roof cutting with constant resistance cable reinforcement reduces mining-induced loads while increasing deformation tolerance, providing a practical solution for stabilizing kilometer-deep soft rock roadways. Full article

This work, conducted within the framework of the international network CRESTE (Coastal Resilience Using Satellites), examines the role of resilience in monitoring coastal evolution across diverse environments in Europe (France, The Netherlands), America (Mexico), Asia (China), and Oceania (Australia). High-resolution morphological datasets, derived from in situ measurements and video monitoring systems, were analyzed for wave- and tide-dominated beaches influenced by both climatic drivers and anthropogenic pressures. Findings indicate that beach resilience is strongly linked to system resistance, which depends on the intensity of climate drivers, including storm frequency, and site-specific conditions related to the type of sediment and its availability, and the presence of anthropogenic activities including coastal structures (e.g., Normandy, Yucatán) and shoreface nourishments (Netherlands). In Batemans Bay (Australia) and Hangzhou Bay (China), assessing the resilience is particularly challenging due to the combined influence of multiple drivers, fluvial inputs, and urban development. Accurate monitoring of coastal resilience across timescales requires accounting for long-term morphological, ecological, and socio-economic processes. This can be enhanced through satellite observations, which, when integrated with in situ measurements, numerical modeling, and artificial intelligence, support a more comprehensive assessment of resilience and refine projections under future climate change and sea-level rise; representing a key focus for further works. Full article

Safeguarding data confidentiality and enforcing precise access regulation in cloud platforms continue to be major research concerns. Attribute-based encryption (ABE) offers a versatile framework for policy-driven control, whereas public key encryption with keyword search (PEKS) supports efficient querying of encrypted datasets. However, ABE lacks keyword search support, and PEKS offers limited control over access policies. To overcome these limitations, attribute-based keyword search (ABKS) schemes have been proposed, with recent advances such as ciphertext-policy decryptable ABKS (CP-DABKS) enabling secure channel-free keyword search. Nevertheless, the existing CP-DABKS schemes still face important challenges: the master public key grows linearly with the attribute universe, secure channels are often required to deliver trapdoors, and many designs remain vulnerable to keyword guessing attacks. This work introduces an efficient CP-DABKS scheme built upon a Type-3 pairing framework to directly overcome these limitations. The proposed design employs a commit-to-point mechanism that prevents linear key growth, eliminates the need for secure trapdoor transmission, and resists keyword guessing attacks. We implement and evaluate the proposed scheme using real-world data from the Enron Email dataset and demonstrate its practicality for secure and searchable cloud-based storage. We also discuss implementation considerations and outline directions for future enhancement of privacy-preserving searchable encryption systems. Full article

Background: Insulin resistance (IR) is a key pathophysiological mechanism linking obesity, type 2 diabetes, and cardiovascular disease. Office workers, due to prolonged sedentary behavior and suboptimal lifestyle patterns, may be particularly susceptible to IR. However, large-scale studies in this occupational group remain scarce. Objective: To evaluate the prevalence of elevated IR risk using non–insulin-based indices—TyG, METS-IR, and SPISE—and their associations with sociodemographic and lifestyle factors in a large sample of Spanish office workers. Methods: This cross-sectional study included 82,020 office workers from Spain (2021–2022). IR risk was assessed using the TyG index, METS-IR, and SPISE, all derived from fasting biochemical and anthropometric data. Sociodemographic and lifestyle variables were self-reported using validated questionnaires. Sex-stratified analyses and multivariate logistic regression models were performed. Results: Men showed significantly higher odds of elevated IR risk compared to women across all indices: TyG (OR = 2.48, 95% CI: 2.37–2.60), METS-IR (OR = 1.47, 95% CI: 1.38–1.57), and SPISE (OR = 1.88, 95% CI: 1.78–1.99). Smoking, physical inactivity, and low adherence to the Mediterranean diet were independently associated with elevated IR scores, regardless of sex or age. Conclusions: A substantial proportion of office workers exhibit elevated insulin resistance risk, particularly among men and those with unhealthy lifestyles. TyG, METS-IR, and SPISE are valuable, low-cost tools for early IR detection in occupational health settings. These findings support the implementation of preventive strategies targeting modifiable behaviors in sedentary working populations. Full article

Accurate assessment of aerodynamic resistance in mine ventilation networks is essential for ensuring operational safety and energy efficiency, yet traditional measurement approaches remain time-consuming and prone to uncertainty. This study presents a novel methodology for constructing digital ventilation models of underground mine workings using markerless LiDAR scanning combined with automated data processing. The proposed procedure includes segmentation of point clouds into sections, calculation of geometric parameters, and direct determination of resistance coefficients, which are subsequently exported to VentSim software. The approach was validated through a case study conducted in a Polish coal mine, where a 369 m ventilation siding was scanned and analyzed. The comparison between numerical simulations and in situ measurements demonstrated strong agreement, with differences not exceeding ±5% for airflow velocity, pressure drop, and total flow rate, while larger deviations were observed for cross-sectional area (+5.1%). The method is limited by potential inaccuracies in determining excavation geometry, which can lead to errors in calculating resistance coefficients, particularly at excavation intersections and at the beginning and end of scanning sections. Point cloud analysis, determination of resistance coefficients for individual sections (segments), spatial transformation, and point cloud reduction, along with integration with VentSim, are based on Python scripts. Calculation results can be easily exported to other computational programs. The proposed approach enables integration with various sensors and allows for assigning this value directly to a given section (segment of the excavation). The method can support the construction of digital twins for mines or underground tunnels. The implementation codes of the developed algorithms have also been made available for educational and scientific purposes under the Modified GNU General Public License v3 (GPLv3). Full article

This study presents an analytical investigation of the thermomechanical stability of hyperbolic doubly curved shells reinforced with graphene origami auxetic metamaterials (GOAMs) and resting on a Pasternak elastic foundation. The proposed model integrates shell geometry, thermal–mechanical loading, and architected auxetic reinforcement to capture their coupled influence on buckling behavior. Stability equations are derived using the First-Order Shear Deformation Theory (FSDT) and the principle of virtual work, while the effective thermoelastic properties of the GOAM phase are obtained through micromechanical homogenization as functions of folding angle, mass fraction, and spatial distribution. Closed-form eigenvalue solutions are achieved with Navier’s method for simply supported boundaries. The results reveal that GOAM reinforcement enhances the critical buckling load at low folding angles, whereas higher folding induces compliance that diminishes stability. The Pasternak shear layer significantly improves buckling resistance up to about 46% with pronounced effects in asymmetrically graded configurations. Compared with conventional composite shells, the proposed GOAM-reinforced shells exhibit tunable, folding-dependent stability responses. These findings highlight the potential of origami-inspired graphene metamaterials for designing lightweight, thermally stable thin-walled structures in aerospace morphing skins and multifunctional mechanical systems. Full article

Effective management of multidrug-resistant cancers depends on effective, localized drug release and accumulation within the tumor microenvironment. In our work, Pluronic P105 and F127 mixed nanogels (PM) were fabricated through self-assembly to combat multidrug-resistant cancer. The approximate diameter of our prepared PM is 115.7 nm, an optimal size for tumor accumulation through the enhanced permeability and retention (EPR) effect. An in vitro drug release assay indicated that ultrasound could accelerate the drug release rate in doxorubicin-loaded Pluronic nanogels (PM/D). Additionally, the resistance reversion index (RRI) in the ultrasound-treated PM/D group was 4.55 and was two times higher than that in the free PM/D group, which represented better MDR reverse performance. Cell experiments demonstrated that, after 3 min of ultrasound, a greater amount of chemo-drug was released and absorbed by the MDR human breast cell line (MCF-7/ADR), resulting in significant cytotoxicity. Such enhanced therapeutic efficiency could be attributed to the combined effects of the two independent mechanisms: (i) ultrasound-controllable drug release realized effective release within resistant tumors with spatial and temporal precision and (ii) the contained Pluronic in the PM/D inhibited P-gp-mediated efflux activity to overcome MDR in tumors. Collectively, our findings support the feasibility of ultrasound-responsive PM as a drug-delivery platform for resistant cancers. Full article

Cancer continues to pose a major global health burden, with conventional therapeutic modalities such as surgical resection, chemotherapy, radiotherapy, and immunotherapy often hindered by limited tumor specificity, substantial systemic toxicity, and the emergence of multidrug resistance. The rapid advancement of nanotechnology has introduced functionalized nanomaterials as innovative tools in the realm of precision oncology. These nanoplatforms possess desirable physicochemical properties, including tunable particle size, favorable biocompatibility, and programmable surface chemistry, which collectively enable enhanced tumor targeting and reduced off-target effects. This review systematically examines recent developments in the application of nanomaterials for cancer therapy, with a focus on several representative nanocarrier systems. These include lipid-based formulations, synthetic polymeric nanoparticles, inorganic nanostructures composed of metallic or non-metallic elements, and carbon-based nanomaterials. In addition, the article outlines key strategies for functionalization, such as ligand-mediated targeting, stimulus-responsive drug release mechanisms, and biomimetic surface engineering to improve in vivo stability and immune evasion. These multifunctional nanocarriers have demonstrated significant potential across a range of therapeutic applications, including targeted drug delivery, photothermal therapy, photodynamic therapy, and cancer immunotherapy. When integrated into combinatorial treatment regimens, they have exhibited synergistic therapeutic effects, contributing to improved efficacy by overcoming tumor heterogeneity and resistance mechanisms. A growing body of preclinical evidence supports their ability to suppress tumor progression, minimize systemic toxicity, and enhance antitumor immune responses. This review further explores the design principles of multifunctional nanoplatforms and their comprehensive application in combination therapies, highlighting their preclinical efficacy. In addition, it critically examines major challenges impeding the clinical translation of nanomedicine. By identifying these obstacles, the review provides a valuable roadmap to guide future research and development. Overall, this work serves as an important reference for researchers, clinicians, and regulatory bodies aiming to advance the safe, effective, and personalized application of nanotechnology in cancer treatment. Full article

This study presents results on developing new copper alloys for electrode caps used in resistance spot welding (RSW) of galvanized steel sheets. Two copper alloys—CuCr0.7Zr0.05 and CuCr0.3Ni0.1Zr0.05—were modified with scandium (Sc) additions of 0.01 and 0.05 wt. %. Within this article, the influence of scandium content on Vickers hardness (HV) and electrical conductivity during alloy aging was investigated. In addition, the electrode life of the produced electrodes was subjected to detailed analysis. The results demonstrated that Sc modification enables an increase in hardness with only a minimal decrease in electrical conductivity. Moreover, Sc-modified electrodes exhibited a significantly reduced diffusion layer thickness in the electrode material, which led to lower degradation of the working face geometry and reduced material loss compared with commercial Cu–Cr–Zr electrodes. Mechanical testing showed that spot joints produced with the new electrodes exceed the minimum shear–tension strength requirements even after 500 welds. These results confirm that the proposed alloying approach extends electrode cap life and improves spot weld quality, supporting its application in industrial RSW. Full article

The present work investigates the electrochemical behavior of the Zr2.5Nb alloy in a biomedical context, emphasizing the influence of electrochemical oxidation treatment on its stability in simulated physiological environments. The alloy samples were oxidized in 1 M H₂SO₄ under controlled voltages (200–275 V) and times (1 min), identifying 200 V–1 min as the optimal condition for obtaining a uniform porous oxide layer with an average pore diameter of ~90 nm. The corrosion resistance was evaluated using open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) in Ringer’s solution and Ringer’s solution containing 40 g/L H₂O₂ to simulate physiological and inflammatory conditions. Electrochemical tests revealed that electrochemically oxidized samples exhibited a polarization resistance up to 14.78 MΩ·cm², about 26 times higher than that of the untreated alloy (0.56 MΩ·cm²). After 77 h of immersion, the oxidized alloy maintained a high resistance (17.54 MΩ·cm²), confirming long-term stability. Scanning Electron Microscopy (SEM–EDX) and X-Ray Diffraction (XRD) analyses highlighted significant increases in oxygen content and the transformation from the monoclinic baddeleyite to the cubic arkelite phase of ZrO₂, contributing to enhanced corrosion resistance. These findings demonstrate that controlled electrochemical oxidation significantly improves the durability of Zr2.5Nb alloy in oxidative environments, supporting its potential for long-term biomedical implant applications. Full article