Search Results (19,435)

This study investigates the influence of synthesis methods and electrode geometry on the physico-chemical properties of 5%Gd-doped SnO₂. Two distinct synthesis routes, co-precipitation and hydrothermal growth, were employed, resulting in powders denoted as SnO₂: Gd 5%-CP and SnO₂: Gd 5%-HT. Morpho-structural and textural analyses reveal a uniform morphology consisting of quasi-spherical nanoparticles with dimensions of ~6 nm and mesoporosity for CP and a non-uniform morphology with larger nanoparticles of ~42 nm, with irregular shapes and macroporosity for the HT sample, respectively. The powders were deposited onto alumina substrates equipped with platinum interdigital electrodes with alternative gaps of 200 μm and 100 μm. The back-side heater allows for variation in the temperature of the layer. Sensing properties assessed under in-field-like atmospheres simulated by a computer-controlled Gas Mixing System reveal higher sensitivity to methane compared to carbon dioxide. Although the sensor signals did not differ quantitatively, they exhibited distinct saturation tendencies with an increasing methane concentration, attributed to the morpho-structure and porosity induced by the synthesis method. Differentiation was achieved by varying the interdigital gap of the electrodes, highlighting different sensor signals and conduction mechanisms, determined by the specific size of the crystallites. Full article

In this investigation, our primary objective is to explore the structural, morphological, and electrical characteristics of Bi_0.75Ba_0.25(FeMn)_0.5O₃ ceramic material synthesized by the sol-gel method. The prepared sample underwent synthesis through the conventional sol-gel technique. Examination through X-ray diffraction (XRD) unveiled a well-defined rhombohedral structure within the R$\acute{3}$C space group. Moreover, to evaluate the purity and nano-grain morphology, we utilized energy dispersive spectroscopy (EDX) and scanning electron microscopy (SEM). Electrical assessments were carried out over a frequency span of 100 Hz to 1 MHz and temperatures ranging from 200 to 340 K. Employing the correlated barrier hopping (CBH) model, we analyzed the AC conductivity of our specimen. The activation energy, determined from both DC conductivity and impedance spectra, demonstrated close correspondence, suggesting that both conductivity and r laxation processes are influenced by similar factors. Notably, the dielectric properties hold significant importance, potentially rendering our sample suitable for electronic applications. Furthermore, we calculated thermodynamic parameters, such as enthalpy (ΔH), entropy change (ΔS), and free energy of activation (ΔF), offering deeper insights into the material’s behavior and conductivity mechanisms. Full article

Demand-responsive transport (DRT) could be an alternative for extending the accessibility of high-speed rail (HSR) servicing cities in rural environments, where fixed public transport does not provide efficient services. This paper proposes a method to analyse the factors that influence the implementation of DRT systems for inter-urban mobility, connecting and integrating towns in rural areas. Methodologically, a vehicle routing problem analysis in a GIS-based environment is applied to a theoretical case study to evaluate the factors that influence DRT efficiency in different scenarios, considering the specific singularities of this kind of inter-urban long-distance mobility. The results suggest the optimal DRT solutions in these rural contexts to be those that, after adjusting the fleet to specific demands, use low-capacity vehicles, which are much better adapted to the geography of sparsely populated areas. Moreover, in adapting DRT systems to HSR travellers’ needs, windows catering to these needs should incorporate the option of setting the pickup or arrival times. This paper demonstrates that DRT systems could reach significant levels of service in rural areas compared with fixed lines and even private vehicles, especially when evaluating key aspects of the system’s efficiency for its implementation. Full article

As a consequence of human activity, waste generation is unavoidable, and its volume and complexity escalate with urbanization, economic progress, and the elevation of living standards in cities. Annually, the world produces about 2.01 billion tons of municipal solid waste, which often lacks environmentally safe management. The importance of solid waste management lies in its role in sustainable development, aimed at reducing the environmental harms from waste creation and disposal. With the expansion of urban populations, waste management systems grow increasingly complex, necessitating more sophisticated optimization strategies. This analysis thoroughly examines the optimization techniques used in solid waste management, assessing their application, benefits, and limitations by using PRISMA 2020. This study, reviewing the literature from 2010 to 2023, divides these techniques into three key areas: waste collection and transportation, waste treatment and disposal, and resource recovery, using tools like mathematical modeling, simulation, and artificial intelligence. It evaluates these strategies against criteria such as cost-efficiency, environmental footprint, energy usage, and social acceptability. Significant progress has been noted in optimizing waste collection and transportation through innovations in routing, bin placement, and the scheduling of vehicles. The paper also explores advancements in waste treatment and disposal, like selecting landfill sites and converting waste to energy, alongside newer methods for resource recovery, including sorting and recycling materials. In conclusion, this review identifies research gaps and suggests directions for future optimization efforts in solid waste management, emphasizing the need for cross-disciplinary collaboration, leveraging new technologies, and adopting tailored approaches to tackle the intricate challenges of managing waste. These insights offer valuable guidance for policymakers, waste management professionals, and researchers involved in crafting sustainable waste strategies. Full article

To date, not many studies have presented evidence of SARS-CoV-2 infecting the female reproductive system. Furthermore, so far, no effect of the administration of anti-COVID 19 vaccines has been reported to affect the quality of oocytes retrieved from women who resorted to assisted reproduction technology (ART). The FF metabolic profiles of women who had been infected by SARS-CoV-2 before IVF treatments or after COVID-19 vaccination were examined by ¹H NMR. Immunochemical characterization of proteins and cytokines involved in the redox and inflammatory pathways was performed. The increased expression of SOD2 and NQO1, the lack of alteration of IL-6 and CXCL10 levels, as well as the increased expression of CD39, suggested that, both sharing similar molecular mechanisms or proceeding along different routes, the redox balance is controlled in the FF of both vaccinated and recovered women compared to controls. The lower amount of metabolites known to have proinflammatory activity, i.e., TMAO and lipids, further supported the biochemical results, suggesting that the FF microenvironment is controlled so as to guarantee oocyte quality and does not compromise the outcome of ART. In terms of the number of blastocysts obtained after ICSI and the pregnancy rate, the results are also comforting. Full article

Numerous factors influence the magnitude and effector phenotype of vaccine-induced CD8⁺ T cells, thereby potentially impacting treatment efficacy. Here, we investigate the effect of vaccination dose, route of immunization, presence of a target antigen-expressing tumor, and heterologous prime-boost with peptide vaccine partner following vaccination with antigen-armed VSV-GP. Our results indicate that a higher vaccine dose increases antigen-specific CD8⁺ T cell proportions while altering the phenotype. The intravenous route induces the highest proportion of antigen-specific CD8⁺ T cells together with the lowest anti-viral response followed by the intraperitoneal, intramuscular, and subcutaneous routes. Moreover, the presence of a B16-OVA tumor serves as pre-prime, thereby increasing OVA-specific CD8⁺ T cells upon vaccination and thus altering the ratio of anti-tumor versus anti-viral CD8⁺ T cells. Interestingly, tumor-specific CD8⁺ T cells exhibit a different phenotype compared to bystander anti-viral CD8⁺ T cells. Finally, the heterologous combination of peptide and viral vaccine elicits the highest proportion of antigen-specific CD8⁺ T cells in the tumor and tumor-draining lymph nodes. In summary, we provide a basic immune characterization of various factors that affect anti-viral and vaccine target-specific CD8⁺ T cell proportions and phenotypes, thereby enhancing our vaccinology knowledge for future vaccine regimen designs. Full article

This paper focuses on the design and implementation of a versatile delivery robot which integrates a secure locking system, GPS navigation, customer authentication, and a camera system for real-time monitoring. The advanced locking system ensures the protection of delivered goods during transit, addressing security concerns. GPS navigation optimizes routes for efficient last-mile deliveries, reducing overall delivery times. Customer authentication adds an extra layer of security, allowing only the designated customer, equipped with a unique authentication method, to unlock and retrieve their parcel. The integrated camera system provides continuous monitoring throughout the delivery process. The combination of these features showcases technological innovation and also addresses critical aspects of security and customer trust in autonomous deliveries. The successful integration of these features positions the delivery robot as a reliable and customer-friendly solution for the evolving landscape of last-mile logistics. Full article

The transition metal cadmium (Cd) is toxic to humans and can induce cellular redox stress and inflammation. Cd is a recognized carcinogen, but the molecular mechanisms associated with its genotoxicity and carcinogenicity are not defined. Therefore, a systematic review was undertaken to examine the scientific literature that has covered the molecular mechanism of Cd genotoxicity and its relationship to cellular redox stress and inflammation. An electronic database search of PubMed, Scopus, and the Web of Science Core Collection was conducted to retrieve the studies that had investigated if Cd genotoxicity was directly linked to the induction of redox stress and inflammation. Studies included exposure to Cd via in vitro and in vivo routes of administration. Of 214 publications retrieved, 10 met the inclusion criteria for this review. Preclinical studies indicate that Cd exposure causes the induction of reactive oxygen species (ROS) and, via concomitant activity of the transcription factor NF-κβ, induces the production of pro-inflammatory cytokines and a cytokine profile consistent with the induction of an allergic response. There is limited information regarding the impact of Cd on cellular signal transduction pathways, and the relationship of this to genotoxicity is still inconclusive. Nevertheless, pre-incubation with the antioxidants, N-acetylcysteine or sulforaphane, or the necroptosis inhibitor, necrostatin-1, reduces Cd toxicity; indicative that these agents may be a beneficial treatment adjunct in cases of Cd poisoning. Collectively, this review highlights that Cd-induced toxicity and associated tissue pathology, and ultimately the carcinogenic potential of Cd, may be driven by redox stress and inflammatory mechanisms. Full article

The identification of spray-drying processing parameters capable of producing particles suitable for pulmonary inhalation with retained bioactivity underpins the development of inhalable biotherapeutics. Effective delivery of biopharmaceuticals via pulmonary delivery routes such as dry powder inhalation (DPI) requires developing techniques that engineer particles to well-defined target profiles while simultaneously minimising protein denaturation. This study examines the simultaneous effects of atomisation gas flow rate on particle properties and retained bioactivity for the model biopharmaceutical lysozyme. The results show that optimising the interplay between atomisation gas flow rate and excipient concentration enables the production of free-flowing powder with retained bioactivity approaching 100%, moisture content below 4%, and D₅₀ < 4 µm, at yields exceeding 50%. The developed methodologies inform the future design of protein-specific spray-drying parameters for inhalable biotherapeutics. Full article

In this study, we present a framework for optimizing pick-up and delivery operations in bike-sharing systems (BSSs), with particular emphasis on inventory rebalancing and vehicle routing to enhance operational efficiency. By employing a hybrid genetic algorithm (HGA), this study integrates sophisticated predictive models with multi-objective optimization techniques to strike a balance between operational efficiency and demand fulfillment in urban bike-share networks. For probabilistic demand forecasting, the DeepAR model is applied to a large number of bike stations clustered by geological proximity to enable stochastic inventory management. Our proposed HGA approach leverages both the genetic algorithm for generating feasible vehicle routes and mixed-integer programming for bike rebalancing to minimize travel distances while maintaining balanced inventory levels across all clustered stations. Through rigorous empirical evaluations, we demonstrate the effectiveness of our proposed methodology in improving service quality, thus making significant contributions to sustainable urban mobility. This study not only pushes the boundaries of theoretical knowledge in BSS logistics optimization but also offers managerial insights for practical implementation, particularly in densely populated urban settings. Full article

Compared with general images, objects in remote sensing (RS) images typically exhibit a conspicuous diversity due to their arbitrary orientations. However, many of the prevalent detectors generally apply an inflexible strategy in setting the angles of anchor, ignoring the fact that the number of possible orientations is predictable. Consequently, their processes integrate numerous superfluous angular considerations and hinder their efficiency. To deal with this situation, we propose a dynamic density-driven estimation network (DDE-Net). We design three core modules in DDE-Net: a density-map and mask generation module (DGM), mask routing prediction module (MRM), and spatial-balance calculation module (SCM). DGM is designed for the generation of a density map and mask, which can extract salient features. MRM is for the prediction of object orientation and corresponding weights, which are used to calculate feature maps. SCM is used to affine transform the convolution kernel, which applies an adaptive weighted compute mechanism to enhance the average feature, so as to balance the spatial difference to the rotation feature extraction. A broad array of experimental evaluations have conclusively shown that our methodology outperforms existing state-of-the-art detectors on common aerial object datasets (DOTA and HRSC2016). Full article

This paper introduces a novel stability metric specifically developed for IQRF wireless mesh sensor networks, emphasizing flooding routing and data collection methodologies, particularly IQRF’s Fast Response Command (FRC) technique. A key feature of this metric is its ability to ensure network resilience against disruptions by effectively utilizing redundant paths in the network. This makes the metric an indispensable tool for field engineers in both the design and deployment of wireless sensor networks. Our findings provide valuable insights, demonstrating the metric’s efficacy in achieving robust and reliable network operations, especially in data collection tasks. The inclusion of redundant paths as a factor in the stability metric significantly enhances its practicality and relevance. Furthermore, this research offers practical ideas for enhancing the design and management of wireless mesh sensor networks. The stability metric uniquely assesses the resilience of data collection activities within these networks, with a focus on the benefits of redundant paths, underscoring the significance of stability in network evaluation. Full article

High levels of vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF)-2 and angiopoietin (ANG)-2 are found in tissues from oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMDs). As might be expected, VEGF, FGF-2, and ANG-2 overexpression parallels the development of new blood and lymphatic vessels that nourish the growing OPMDs or OSCCs and provide the latter with metastatic routes. Notably, VEGF, FGF-2, and ANG-2 are also linked to the epithelial-to-mesenchymal transition (EMT), a trans-differentiation process that respectively promotes or exasperates the invasiveness of normal and neoplastic oral epithelial cells. Here, we have summarized published work regarding the impact that the interplay among VEGF, FGF-2, ANG-2, vessel generation, and EMT has on oral carcinogenesis. Results from the reviewed studies indicate that VEGF, FGF-2, and ANG-2 spark either protein kinase B (AKT) or mitogen-activated protein kinases (MAPK), two signaling pathways that can promote both EMT and new vessels’ formation in OPMDs and OSCCs. Since EMT and vessel generation are key to the onset and progression of OSCC, as well as to its radio- and chemo-resistance, these data encourage including AKT or MAPK inhibitors and/or antiangiogenic drugs in the treatment of this malignancy. Full article

In recent years, with the rapidly aging population, alleviating the pressure on medical staff has become a critical issue. To improve the work efficiency of medical staff and reduce the risk of infection, we consider the multi-trip autonomous mobile robot (AMR) routing problem in a stochastic environment. Our goal is to minimize the total expected operating cost and maximize the total service quality for patients, ensuring that each route violates the vehicle capacity and the time window with only a minimal probability. The travel time of AMRs is stochastically affected by the surrounding environment; the demand for each ward is unknown until the AMR reaches the ward, and the service time is linearly related to the actual demand. We developed a population-based tabu search algorithm (PTS) that combines the genetic algorithm with the tabu search algorithm to solve this problem. Extensive numerical experiments were conducted on the modified Solomon instances to demonstrate the efficiency of the PTS algorithm and reveal the impacts of the confidence level on the optimal solution, providing insights for decision-makers to devise delivery schemes that balance operating costs with patient satisfaction. Full article

Furfural is a well-recognized biomass platform. Hydrogenation and reductive amination of furfural are two principal routes in the valorization of this compound. In both reactions, the presence of reducible species (SMSI effect) and acid sites could favor the selectivity toward some interesting products. Both conditions could be obtained using metal particles supported on reducible mixed oxides. In this work, we investigate the use of Pt/Nb₂O₅-Al₂O₃ catalysts for the hydrogenation and reductive amination of furfural at distinct Nb₂O₅ contents. A decaniobate salt was used as a precursor of Nb₂O₅. The solids were reduced at 500 °C to assure the migration of reducible NbO_x species. The solids were characterized by XRD, Raman spectroscopy, HR-TEM, N₂-physisorption, NH₃-TPD and Pyr-DRIFTS. The results showed that higher Nb₂O₅ loadings led to a lower distribution of Al₂O₃ and Pt, favoring the catalysts’ acidity. This fact implies that large particle size and the presence of Nb₂O₅ islands favor the formation of furfuryl alcohol but have a detrimental effect on the amine formation in the reductive amination of furfural. Full article