Search Results (7,505)

Introduction: This study examined the relationship between Indigenous identity, perceived stress, and healthcare utilization for Indigenous students on-campus. Methods: Potential participants included undergraduate and graduate Indigenous students from Tribal Nations within the United States. Participants were recruited through community partnerships and in person communication. This survey included the Perceived Stress Scale (PSS-10), the Multiethnic Identity Measure (MEIM), and university Campus Health Service Health and Wellness Survey. Results: 153 Indigenous students from United States-based Tribal Nations participated in this survey. While there appears to be a relationship between Indigenous identity, perceived stress, and Campus Health utilization, the results were not significant for the second tertile (OR: 1.1 (0.4, 2.7)) or third tertile (1.4 (0.5, 3.3)). Students who reported “Yes” or “Unsure” to questions on if their insurance needed them to go outside of the university were far less likely to use Campus Health (Yes OR: 0.2 (0.08–0.5)); (Unsure OR: 0.09 (0.03–0.3)) and CAPS (Yes OR: 0.2 (0.09–0.6)); (Unsure OR: 0.2 (0.04–0.4)). Discussion: This study saw a complex relationship between Indigenous identity, perceived stress, and campus health utilization; however, the findings are not statistically significant. There are distinctions in on campus health care usage when adjusting for undergraduate or graduate student status and health insurance literacy. Conclusion: The research findings offer many promising avenues for future work around Indigenous identity, affordability of healthcare, and importance of health literacy. Full article

Condition assessment of reinforced concrete structures presents a significant challenge worldwide as structures built in the post-war construction period (1950s–1970s) reach end of service life. The alkali-silica reaction (ASR) is one of several damage mechanisms which commonly affect infrastructure in Canada. Frequent freeze-thaw cycles and heavy use of de-icing salts in winter as well as high heat and humidity in summer are expected to have intensified ASR-induced damage. This work investigates five segments of a pier cap—PC, which had undergone encapsulation repair, and four segments of a pier shaft—PS, which represented dry and semi-submerged conditions, removed from a highway bridge constructed starting in 1957. Preliminary evaluation through visual inspection (conventional, qualitative and quantitative using the cracking index—CI) and non-destructive techniques (rebound hammer—RBH, ultrasonic pulse velocity—UPV and surface resistivity) was conducted on both internal (i.e., cut during decommissioning) and external (i.e., exposed while in service) surfaces of five PC segments and four PS segments. Differences in geometry, exposure conditions and repair history from the two members were found to have limited impact on the results of quantitative tests (i.e., CI, RBH and UPV results with average values of 1.6 mm/m, 37 MPa and 2.4 Km/s, respectively) while still exhibiting qualitative differences in visual determination (i.e., crack patterns, surface appearance and crack widths). Full article

We report here on the synthesis and characterization of three novel isoindigo (II)-based organic semiconductors. The three dyes are based on an electron acceptor II core, symmetrically linked to two 3-octylthiophene donor rings; this common fragment, easily synthesizable, is end-capped with three different auxiliary electron acceptor groups, 1,1-Dicyanomethylene-3-Indanone (IDM) and two derivatives of it, bearing a bromine atom in position 5 or 6 of the IDM ring. The effect of the bromination and of the position of the bromine atom on the chemical–physical and electrical properties of the compounds were examined by means of thermal, optical, and electrochemical analysis; the electronic properties were investigated in more details at the DFT level. The novel compounds were used as active layers in organic field effect transistors: all the II derivatives were n-type unipolar semiconductors with electron mobilities ranging between 10⁻³ and 10⁻⁴ cm²/V∙s. Full article

The production of green nanomaterials has drawn considerable interest lately in the fields of tissue engineering and biomedicine. Thus, the environmentally friendly synthesis of ZnO and CuO nanoparticles (NPs) utilizing orange peel extract as a natural capping and reducing agent is the main focus of this study. Our comprehensive approach allows for a direct and systematic comparison of physicochemical attributes, biocompatibility, and antimicrobial activity under identical experimental circumstances, in contrast to other research that looked at individual nanoparticles under different conditions. The produced nanoparticles were characterized by techniques such as FTIR, XRD, SEM, TGA, and zeta potential assessment. MG-63 osteoblast-like cells, primary human dermal fibroblast BJ cells, and murine fibroblast L929 cells were used to evaluate biocompatibility using the MTT assay. The results showed dose-dependent cytotoxicity, especially above 25 µg/mL. Furthermore, both qualitative (growth inhibition zone diameter) and quantitative (minimum inhibitory concentration, MIC) techniques were used to assess the antimicrobial efficacy against Candida albicans and Gram-positive and Gram-negative bacteria. According to the obtained results, ZnO NPs showed broad-spectrum efficacy, whereas CuO NPs showed excellent antibacterial activity against Gram-positive bacteria (e.g., S. aureus, MIC = 0.313 μg/μL). The study highlights the potential of green-synthesized nanoparticles for utilization in biomedical applications, and it stresses the need for additional mechanistic research, including ROS measurement, to completely understand how they work. Full article

The influence of minor components on leaching molecular iodine (I₂) through polypropylene (PP)-based packaging from a povidone iodine-based (PVP-I) formulation, simulating an ophthalmic application, was evaluated. I₂ is a cheap, broad-spectrum, and multi-target antiseptic. Nevertheless, it is volatile, and the prolonged storage of I₂-based formulations is demanding in plastic packaging because of transmission through the material. Therefore, we explored the possibility of moderating the loss of I₂ from an iodophor formulation by introducing small amounts of molecular iodine into the polymer material commonly used in eyedropper caps, i.e., PP. Thus, PP was blended via an extrusion process with a polymeric complex containing iodine (such as PVP-I) or with a second polymeric component able to complex the I₂ released from an iodophor solution. The aim of this work was to introduce I₂ into PP-based polymer matrices without using organic solvents and indirectly, i.e., through the addition of components that could generate molecular iodine or complex it in the solid phase, as I₂ is heat-sensitive. To increase the miscibility between PP and PVP-I, poly(N-vinylpyrrolidone) (PVP) or a vinyl pyrrolidone vinyl acetate copolymer 55/45 (Sokalan) were added as compatibilizers. The PP-based binary and ternary blends, in granular or sheet form, were characterized thermally (Differential Scanning Calorimetry, DSC, and Thermogravimetric analysis, TGA), mechanically (tensile tests), morphologically (scanning electron microscopy (SEM)), and chemically (attenuated total reflectance Fourier transform infrared (ATR-FTIR)). Additionally, the variation in wettability induced by the introduction of the hydrophilic minority components was determined by static contact angle measurements (static contact angle (SCA)), and tests were carried out to determine the barrier properties against oxygen (oxygen transmission rate (OTR)) and molecular iodine. The I₂ leaching of the different blends was compared with that of PP by monitoring the I₂ retention in a buffered PVP-I solution via UV-vis spectroscopy. Overall, the experimental data showed the capability of the minority components in the blends to increase thermal stability as well as act as a barrier to oxygen. Additionally, the PP blend with PVP-I induced a reduction in molecular iodine leaching in comparison with PP. Full article

This paper presents a deep reinforcement learning-based demand response (DR) optimization framework for active distribution networks under uncertainty and user heterogeneity. The proposed model utilizes a Double Deep Q-Network (Double DQN) to learn adaptive, multi-period DR strategies across residential, commercial, and electric vehicle (EV) participants in a 24 h rolling horizon. By incorporating a structured state representation—including forecasted load, photovoltaic (PV) output, dynamic pricing, historical DR actions, and voltage states—the agent autonomously learns control policies that minimize total operational costs while maintaining grid feasibility and voltage stability. The physical system is modeled via detailed constraints, including power flow balance, voltage magnitude bounds, PV curtailment caps, deferrable load recovery windows, and user-specific availability envelopes. A case study based on a modified IEEE 33-bus distribution network with embedded PV and DR nodes demonstrates the framework’s effectiveness. Simulation results show that the proposed method achieves significant cost savings (up to 35% over baseline), enhances PV absorption, reduces load variance by 42%, and maintains voltage profiles within safe operational thresholds. Training curves confirm smooth Q-value convergence and stable policy performance, while spatiotemporal visualizations reveal interpretable DR behavior aligned with both economic and physical system constraints. This work contributes a scalable, model-free approach for intelligent DR coordination in smart grids, integrating learning-based control with physical grid realism. The modular design allows for future extension to multi-agent systems, storage coordination, and market-integrated DR scheduling. The results position Double DQN as a promising architecture for operational decision-making in AI-enabled distribution networks. Full article

Background: Dental offices and clinics utilize a variety of dental materials that are delivered in reusable containers and dispensers. However, many of these materials, including NeoPutty, BC Putty, Flowable, and Diapex, may be subject to bacterial contamination and microbial exposures from the surrounding dental office environment. Objectives: The aim of this study was to quantify and identify microbial contamination, specifically in regard to these reusable dental materials. Methods: Surfaces of new and used reusable and resealable tubes where the material dispenses and the interior surfaces of the cap were swabbed and cultured. DNA was isolated from each sample and quantitative polymerase chain reaction (qPCR) was performed to determine the presence or absence of microbial contamination, as well as the relative abundance. Results: Microbial contamination was observed among all of the “in use” samples from both the dispensing end and the interior surfaces of the cap and was strongly associated with the amount of usage. Conclusions: These data suggest that environmental contamination may be present in measurable and quantifiable amounts on reusable and resealable dental materials, which suggest the need to create protocols for sanitizing the surfaces of reusable materials to reduce the presence of microbial contamination identified in similar clinical settings. Full article

Aiming to address the seismic vulnerability of long-span continuous rigid-frame bridges in high-intensity seismic zones, this study proposes to use a novel annular steel wire rope damper spherical bearing (SWD-SB) to dissipate the input earthquake energy and reduce the seismic responses. Firstly, the structural configuration and mechanical model of the new isolation bearing are introduced. Then, based on the dynamic finite element formulation, the equation of motion of a continuous rigid-frame bridge with the new isolation bearings is established, where the soil-structure interaction is considered. In a practical engineering case, the dynamic responses of the Pingchuan Yellow river bridge with the SWD-SB bearings are calculated and analyzed under multi-level earthquakes including the E1 and E2 waves. The results show that, compared with the bidirectional movable pot bearings, the SWD-SB significantly reduces the internal forces and displacement responses at the critical locations of the bridge. Under the E2 earthquake, the peak bending moments at the basement of main piers and at the pile caps are reduced by up to 72.6% and 44.7%, respectively, while the maximum displacement at the top of the main piers decreases by about 34.6%. The overall structural performance remains elastic except the SWD-SB bearings, meeting the two-stage seismic design objective. This paper further analyzes the hysteretic energy dissipation characteristics of the SWD-SB, highlighting its advantages in energy dissipation, deformation coordination, and self-centering capability. The research results demonstrate that the steel wire rope isolation bearings can offer an efficient and durable seismic protection for long-span continuous rigid-frame bridges in high-intensity seismic regions. Full article

As one of the main sources of global greenhouse gas emissions, the low-carbon transformation and emission reduction in the construction industry are inevitable requirements for addressing climate change. Under cap-and-trade regulations, Carbon emission rights have become a key production factor. However, the price of carbon emission rights is highly random. Taking the EU carbon market in 2024 as an example, the carbon price fluctuated by more than 35%, soaring from 65 euros per ton to 80 euros per ton and then falling back. Such sharp fluctuations not only increase the cost uncertainty of enterprises but also complicate the investment decisions for emission reduction. Therefore, enterprises can enhance the flexibility of carbon emission rights trading decisions through option strategies, helping them hedge against the risks of carbon price fluctuations, and at the same time improve market liquidity and risk management capabilities. Against this background, based on the carbon cap-and-trade policy, this paper introduces the two-way option strategy into the construction supply chain game model composed of general contractors and subcontractors, and studies to obtain the optimal carbon reduction volume, carbon option purchase volume, maximum expected profit of general contractors, subcontractors and profit distribution ratio. This study shows that two-way options play a crucial role in optimizing supply decision-making and emission reduction strategies. Under the decentralized model, emission reduction responsibilities are often shifted to subcontractors by the general contractor, resulting in a decline in overall mitigation effectiveness. Furthermore, appropriately lowering the carbon emission benchmark can strengthen enterprises’ incentives for emission reduction and significantly enhance the profitability of the supply chain. The study further suggests that general contractors should enhance their competitiveness by developing environmentally friendly technologies and improving their ability to reduce emissions on their own. Meanwhile, subcontractors need to actively participate in the collaborative efforts through revenue-sharing contracts. This study reveals the strategic value of two-way carbon options in construction supply chain carbon trading and provides theoretical support for the formulation of carbon market policies, contributing to the low-carbon transition of the construction supply chain. Full article

The GaN-on-Si virtual substrate is now an indispensable platform for the application of GaN in the fields of power devices, radio frequency, light-emitting devices, etc. Such applications are still in need of more effective stress balancing techniques to achieve higher quality and stress balance in GaN-on-Si at a lower thickness. In this study, three promising practical prototypes of highly effective stress-balancing structures are proposed to realize the concept of an ideal AlN interlayer (AlN-IL) featuring a completely relaxed lower AlN/GaN interface and a fully strained upper GaN/AlN interface. The first is a single-layer AlN interlayer grown via precursor pulsed-injection (PI-AlN-IL). The second combines a low-temperature AlN (LT-AlN) underlayer with a PI-AlN-IL. The third integrates LT-AlN with a high-temperature AlN cap. Compared with optimal conventional single-layer AlN interlayer references, all these designs more effectively induced compressive stress and strain in overlying GaN layers. This study opens new technical paths to balancing stress in GaN-on-Si systems at a reduced thickness more efficiently. Full article

Silver nanoparticle (AgNP) biosynthesis using propolis extracts as capping and reducing agents presents multiple opportunities for solving many biological challenges. This study demonstrates a sustainable, low toxicity, and high production cost phytochemical synthesis of AgNPs using propolis extracts and microwaves. Biosynthesized with propolis, AgNPs are analyzed by various methods: phytochemical, physicochemical, and morphological, such as TEM. The determined antimicrobial and antioxidant activity of propolis extracts is compared with the activity of green synthesized AgNPs with propolis. The green synthesized AgNPs are spherically shaped with an average size ranging from 6 to 40 nm. The biosynthesized AgNPs demonstrate potential antibacterial activity on tested microorganism strains two folds higher than pure propolis extracts. Full article

Due to high sedimentation rate up to ~1 m/year, mud-capped dredge pits (MCDP) are often considered natural laboratories for studying sedimentary processes, slope stability and the impacts of dredging activities on marine environments. Although many studies have been performed on the Louisiana shelf, there is a lack of high spatial resolution research covering the eastern, central and western Louisiana shelf to comprehensively investigate sediment infilling. Eighteen vibracores were collected from the Peveto Channel dredge pit (PC), Raccoon Island dredge pit (RI) and Sandy Point dredge pit (SP), and more than 1300 samples were analyzed to study the spatial variation in surficial sediment using statistical analyses. Our results indicate that the inner Louisiana continental shelf is silt-dominated, and there was no consistent grain size variation when comparing the sediment within the pits with that outside the pits. Skewness emerged as a prominent factor in the RI and SP, while standard deviation was the most influential in the PC. Our analysis shows also that two principal components are confirmed and account for more than 95% of the total grain size variance. Full article

Rhizoctonia solani root rot (RSRR) is a major disease that significantly reduces soybean yields, causing substantial economic losses to global soybean production. To elucidate the genetic basis of RSRR resistance, 310 soybean germplasm accessions were evaluated using the disease severity index (DSI) following inoculation with R. solani. Among these accessions, 46.13% were susceptible, and only 2.26% exhibited high resistance. Utilizing resequencing data consisting of 738,561 Single Nucleotide Polymorphism (SNP) loci, a genome-wide association study (GWAS) was performed by integrating both general linear model (GLM) and mixed linear model (MLM) approaches, resulting in the identification of 21 SNPs significantly associated with resistance on chromosomes 3, 13, 15, 16, 17, and 18, and six candidate genes. RT-qPCR expression analysis revealed that four genes, including Glyma.03G166300, Glyma.03G168100, Glyma.13G212700, and Glyma.13G212300, were significantly upregulated in resistant genotypes after inoculation. Furthermore, Cleaved Amplified Polymorphic Sequences (CAPS) and Kompetitive Allele Specific PCR (KASP) molecular markers were successfully developed based on the RSRR-associated SNPs S3_38086892, S3_38247290, and S13_32595026, providing effective tools for marker-assisted selection (MAS). The findings strengthen our genetic knowledge concerning RSRR resistance and contribute to the molecular breeding of resistant soybean cultivars. Full article

Fine-grained intertidal sediments are typically characterized by low hydraulic conductivity and high nutrient loads, conditions that hinder biogeochemical recovery and exacerbate eutrophication. This study examined the feasibility of calcium-rich steel slag (SS) as a multifunctional capping material for improving both physical and chemical properties of cohesive sediments. Short-term (24 h) column experiments with two slag dosages (25 g and 50 g) revealed that the higher dosage (SS50) increased sediment hydraulic conductivity by 113.2%, likely through Ca²⁺-mediated flocculation and enhanced pore connectivity. Phosphate (PO₄-P) in pore water decreased by up to 64.1%, and effluent dissolved inorganic nitrogen (DIN) declined by 62.8%, indicating combined effects of Ca-driven precipitation, adsorption, and enhanced flushing. However, SS addition also raised pore water pH (to 11.8) and lowered redox potential, leading to transient phosphate release at the effluent boundary under reducing conditions. Cation analysis confirmed Ca²⁺ stability and Na⁺ reduction, suggesting improved sediment structural integrity. The results suggest that steel slag is a promising reactive capping material capable of enhancing permeability and controlling nutrient release in cohesive coastal sediments, yet further investigation into long-term ecological effects and dosage optimization is necessary. Full article

Electroencephalography (EEG) is a non-invasive biosensing platform with a spatial-frequency content that is of significant relevance for a multitude of aspects in the neurosciences, ranging from optimal spatial sampling of the EEG to the design of spatial filters and source reconstruction. In the past, simplified spherical head models had to be used for this analysis. We propose a method for spatial frequency analysis in EEG for realistically shaped volume conductors, and we exemplify our method with a five-compartment Boundary Element Method (BEM) model of the head. We employ the recently developed technique for spatial harmonic analysis (Sphara), which allows for spatial Fourier analysis on arbitrarily shaped surfaces in space. We first validate and compare Sphara with the established method for spatial Fourier analysis on spherical surfaces, discrete spherical harmonics, using a spherical volume conductor. We provide uncertainty limits for Sphara. We derive relationships between the signal-to-noise ratio (SNR) and the required spatial sampling of the EEG. Our results demonstrate that conventional 10–20 sampling might misestimate EEG power by up to 50%, and even 64 electrodes might misestimate EEG power by up to 15%. Our results also provide insights into the targeting problem of transcranial electric stimulation. Full article