Search Results (44,215)

Novel AB-Polybenzimidazole (AB-PBI)/TiO₂ nanocomposite membranes have been prepared using a synthetic green chemistry approach. Modified Eaton’s reagent (methansulfonic acid/P₂O₅) was used as both reaction media for microwave-assisted synthesis of AB-PBI and as an efficient dispersant of partially agglomerated titanium dioxide powders. Composite membranes of 80 µm thickness have been prepared by a film casting approach involving subsequent anti-solvent inversion in order to obtain porous composite membranes possessing high sorption capacity. The maximal TiO₂ filler content achieved was 20 wt.% TiO₂ nanoparticles (NPs). Titania particles were green synthesized (using a different content of Mentha Spicata (MS) aqueous extract) by hydrothermal activation (150 °C), followed by thermal treatment at 400 °C. The various methods such as powder X-ray diffraction and Thermogravimetric analyses, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Energy-dispersive X-ray spectroscopy, Electronic paramagnetic resonance, Scanning Electron Microscopy and Transmission Electron Microscopy have been used to study the phase and surface composition, structure, morphology, and thermal behavior of the synthesized nanocomposite membranes. The photocatalytic ability of the so-prepared AB-Polybenzimidazole/bio-TiO₂ membranes was studied for decolorization of Reactive Black 5 (RB5) as a model azo dye pollutant under UV light illumination. The polymer membrane in basic form, containing TiO₂ particles, was obtained with a 40 mL quantity of the MS extract, exhibiting the highest decolorization rate (96%) after 180 min of UV irradiation. The so-prepared AB-Polybenzimidazole/TiO₂ samples have a powerful antibacterial effect on E. coli when irradiated by UV light. Full article

Porous activated carbons (AC-AN and AC-AO) for toluene adsorption were prepared starting from brewer’s grain biomass pretreated with microorganisms (Aspergillus niger van Tieghem for AC-AN and Aspergillus oryzae RIB40 for AC-AO). The structures and chemical properties of the three activated carbon materials (AC-AN, AC-AO, and AC that was not pretreated with microorganisms) were characterized by N₂ adsorption–desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The adsorption behavior of the three activated carbons for toluene was studied and correlated with the physical and chemical properties of these materials. The results suggested that the activated carbons prepared by microbial pretreatment had a rougher morphology, higher specific surface area, richer pore structure, fewer oxygen-containing functional groups on the surface, and better adsorption performance for toluene (increased by 31.5% and 18.3% with AC-AN and AC-AO, respectively) compared with the untreated activated carbon (AC). The Thomas model was used to fit the toluene adsorption data, indicating that the rich pore structure accelerated the kinetic process of toluene adsorption. Therefore, appropriate microbial pretreatment of the feedstock that is used to prepare activated carbon can effectively improve its adsorption capacity towards toluene. Full article

Biological invasions pose a major environmental challenge, often facilitating the unregulated dissemination of pathogens and parasites associated with their hosts. These pathogens can severely impact native and cultivated species, with far-reaching ecological and economic consequences. Despite their importance, the mycobiota associated with invasive plant species remains relatively understudied, posing a complex challenge for researchers. The aim of this manuscript is to underscore the most significant threats posed by the uncontrolled transmission of fungal pathogens from invasive alien plants to native environments and agricultural systems, and to identify the factors influencing this phenomenon. We emphasize the role of pathogen spillback and spillover mechanisms in the domestication of invasive alien plants. The influence of environmental, host, and pathogen-related factors on the survival of fungal pathogens were also investigated. Finally, we explore the technical and legal feasibility of using plant pathogens as “green agents” to control invasive alien plants. Full article

The limited coverage of terrestrial base stations and the limited transmission distance and onboard resources of satellite communications make it difficult to ensure the quality of communication services for marine users by relying only on satellites and terrestrial base stations. In contrast, UAVs, as flexible mobile communication nodes, have the capacity for dynamic deployment and real-time adjustment. They can effectively make up for the communication blind spots of traditional satellites and ground base stations in the marine environment, especially in the vast and unpredictable marine environment. Considering the mobility of maritime users, one can effectively reduce the communication delay and optimize the deployment scheme of UAVs by predicting their sailing trajectories in advance, thus enhancing the communication service quality. Therefore, this paper proposes a communication coverage model based on mobile user route prediction and a UAV dynamic deployment algorithm (RUDD). It aims to optimize the coverage efficiency of the maritime communication network, minimize the communication delay, and effectively reduce the energy consumption of UAVs. In this algorithm, the RUDD algorithm employs a modified Long Short-Term Memory (LSTM) network to predict the maritime user’s trajectory, utilizing its strengths in processing time-series data to provide accurate predictions. The prediction results are then used to guide the Proximal Policy Optimization (PPO) algorithm for the dynamic deployment of UAVs. The PPO algorithm can optimize the deployment strategy in dynamic environments, improve communication coverage, and reduce energy consumption. Simulation results show that the proposed algorithm can complement the existing satellite and terrestrial networks well in terms of coverage, with a communication coverage rate of more than 95%, which significantly improves the communication quality of marine users in areas far from land and beyond the reach of traditional networks, and enhances network reliability and user experience. Full article

Background/Objectives: During the pandemic, client-facing workers were perceived to be at greater risk of SARS-CoV-2 infection. This study investigated the risk factors for SARS-CoV-2 infection among a cohort of 304 retail workers in the Quebec City metropolitan area. Methods: After providing consent, participants were interviewed to gather information on demographic, socioeconomic, behavioural, and occupational variables. They were subsequently followed for up to five visits, scheduled every 12 ± 4 weeks. The study covered critical periods before and during the emergence of the Omicron variants and included retrospective reporting of COVID-19 symptoms and virus detection tests to capture the pandemic’s early stages. Results: During the observation period, 173 (57%) participants experienced a first episode of COVID-19. Serological evidence of recent infection was detected in 160 participants (53%), while 117 (38%) reported a positive virus detection test. In adjusted analyses, risk factors for infection included younger age, a diagnosis of lung disease, longer weekly working hours, more frequent social gatherings, and having received fewer than three doses of vaccine. Notably, the increased risk associated with younger age and longer working hours was observed only after the relaxation of public health measures in the spring of 2022. Conclusions: These data suggest that during the early years of the pandemic when strict public health measures were in place, retail work was not a significant risk factor for SARS-CoV-2 infection in Quebec City metropolitan area. These findings highlight the complex dynamics of COVID-19 transmission and the effectiveness of workplace protective measures. Full article

Aedes aegypti is a vector responsible for the transmission of various arboviruses and is considered by the World Health Organization to be one of the main public health problems in the world. This study evaluated the larvicidal and oviposition activity of essential oils from Abies sibirica, Pogostemon cablin and Juniperus communis and their formulations. Chromatographic analysis by GCMS identified a total of 28, 52 and 18 compounds for the oils of the species A. sibirica, J. communis and P. cablin, respectively. The larvicidal bioassays showed an LC₅₀ of 67.53 ppm, 92.45 ppm and 35.95 ppm, respectively, for A. sibirica (A), J. communis (J) and P. cablin (P) as well as their binary (J + P, 39.50 ppm; A + P, 51.64 ppm) and ternary (A + J + P, 66.99 ppm) formulations. These oils and formulations also showed deterrent activity at the larvicidal concentrations tested (A. sibirica: OAI: −0.41; J. communis: OAI: −0.31; P. cablin: OAI: −0.62; A + J + P: −0.30; A + P: −0.68; A + J: −0.29; and J + P: −0.30). The oils and their formulations are a potential larvicidal source for mitigating the proliferation of diseases by this vector. Full article

Defect detection and classification in super-high reflector mirrors and their substrates are crucial for manufacturing laser gyroscope systems. This paper presents a prototype designed to meet the requirements for the reflection and transmission of laser gyroscope mirror substrates. The prototype featured two measurement channels (bright field and dark field) and could detect defects on patterned and unpatterned surfaces. Key components were simulated using Ansys software, (Ansys Workbench 2022 R1)which showed a maximum static deformation of 4.65 μm, a resonant frequency of at least around 230 Hz, and a maximum stress of 9.86 MPa under transportation conditions (GJB150.16A-2009). These results confirm the prototype’s stability for optical performance testing and structural design. The experimental testing on laser gyroscope reflector substrates and USAF 1951 plates demonstrated that the prototype effectively detected defects on reflection and transmission surfaces, with a detection resolution that exceeded 170 nm, which met the design requirements. Full article

Onecut/Hnf6 (Oc) genes play an important role in the proper formation of retinal cells in vertebrates, in particular horizontal, retinal ganglion and amacrine cells. However, it is not fully known how the unique and combined action of multiple Oc gene copies leads to the induction and differentiation of specific retinal cell types. To gain new insights on how Oc genes influence retina formation, we have examined the developmental role of oc1, oc2 and oc-like genes during eye formation in the non-mammalian vertebrate zebrafish Danio rerio. By using single and multiple morpholino knockdown of three zebrafish Oc genes we provide evidence for the independent and redundant role of each gene in the formation of photoreceptors and other retinal tissues. Through comparison of Oc genetic pathways in photoreceptor differentiation among chordates we demonstrate their mechanism of action through a series of conserved target genes involved in neural transmission. Full article

Given the increasing environmental pressures, it is essential that agriculture achieves the goal of sustainable and low-carbon development. In 2010, China, as the top carbon emitter, introduced a policy on agricultural land lease (ALL), which has been met with considerable approval from farmers and has resulted in a notable surge in the rate of ALL within the country. Nevertheless, the question of how the ALL policy affects agricultural carbon emissions (ACEs) remains unanswered. What are the transmission mechanisms? To answer these questions, this paper presents an equilibrium model that accounts for the heterogeneous production efficiency among farmers. It offers a theoretical analysis of the impact of ALL policy on agricultural carbon emission reduction (ACER) and presents an empirical test of this impact using a difference-in-differences (DID) model. Our research shows that the ALL policy gives impetus to ACER. This conclusion persists even after conducting the robustness and endogeneity tests. The mechanism posits that the policy achieves ACER through reducing the proportion of rural agricultural employees. Heterogeneity analysis indicates that the policy effect is significant in both the northern and southern regions of China. Nonetheless, the effect is only observable in economically developed areas, regions with high chemical fertilizer application rates, and areas with restricted agricultural progress. This study elucidates the connection between land transfer and agricultural carbon emissions, offering empirical evidence to support the advancement of green and low-carbon agricultural development. Full article

The analysis conducted herein has shown that the efficiency of smoke precipitation can be improved by additionally making smoke particles interact with ultrasonic (US) oscillations. Because the efficiency of US coagulation lowers when small particles assemble into agglomerates, the authors of this work have suggested studying how smoke particles interact with complex sound fields. The fields are formed by at least two US transducers which work at a similar frequency or on frequencies with small deviations. To form these fields, high-efficiency bending wave ultrasonic transducers have been developed and suggested. It has been shown that a complex ultrasonic field significantly enhances smoke precipitation. The field in question was constructed by simultaneously emitting 22 kHz US oscillations with a sound pressure level no lower than 140 dB at a distance of 1 m. The difference in US oscillations’ frequencies was no more than 300 Hz. Due to the effect of multi-frequency ultrasonic oscillations induced in the experimental smoke chamber, it was possible to provide a transmissivity value of 0.8 at a distance of 1 m from the transducers and 0.9 at a distance of 2 m. Thus, the uniform visibility improvement and complete suppression of incoming smoke was achieved. At the same time, the dual-frequency effect does not require an increase in ultrasonic energy for smoke due to the agglomeration of small particles under the influence of high-frequency ultrasonic vibrations and the further aggregation of the formed agglomerates by creating conditions for the additional rotational movement of the agglomerates due to low-frequency vibrations. Full article

Coenzyme Q10 (CoQ10) is a powerful antioxidant. However, the poor water solubility and low bioavailability still remain challenges for its application. An embedded delivery system of CoQ10 based on whey protein concentrate (WPC) and polymerized whey protein concentrate (PWPC) was prepared, and the physicochemical properties, antioxidant capacity and bioavailability were characterized in this study. Both groups of nanoparticles showed a particle size distribution from 241 to 331 nm in the protein-to-CoQ10 mass ratio range of 100:1 to 20:1. In addition, the minimum polydispersity index value was observed at the mass ratio of 20:1. Differential scanning calorimetry and Fourier transform infrared spectra analysis revealed that the CoQ10 was successfully dispersed in the WPC and PWPC particles through hydrophobic interaction in both groups in addition to the hydrogen bond present in the WPC group. All nanoparticles exhibited irregular spherical or aggregate structure in the transmission electron microscopy diagram. The PWPC-based nanoparticles showed a slightly higher antioxidant capacity than that of the WPC, and both values were significantly higher than that of its corresponding physical mixture and free CoQ10 (p < 0.05). The results of the simulated gastrointestinal digestion experiments denoted that these two nanoparticles could protect CoQ10 from gastric digestion and then deliver it to the intestine. Compared with its free state, the bioavailability of CoQ10 embedded in WPC and PWPC increased by nearly 7.58 times and 7.48 times, respectively. The data indicated that WPC and PWPC could be effective delivery carriers to enhance the bioavailability of active substances like CoQ10. Full article

The motor gear system (MGS) is recognized for its potential in enhancing transmission efficiency and optimizing space utilization. However, the system is subjected to challenges, notably the occurrence of abnormal vibrations. These issues stem from the dynamic interaction between the motor and gears, the presence of nonlinear factors in gear system, and the impact of gear faults, all of which contribute to complex vibration patterns. Traditional dynamic models have been found to be inadequate in effectively addressing the complexities associated with electromechanical coupling problems in MGS. To address these limitations, a comprehensive analysis approach is proposed in this paper, which is grounded in the development of an electromechanical coupling model. This method involves establishing a coupled dynamic model of the motor and gear system, integrating numerical simulations, and experimental validations to thoroughly analyze the vibration characteristics of the system. Through this multifaceted methodology, a detailed analysis of the system’s vibration characteristics is conducted. The results indicate that internal excitations from tooth root cracks not only directly affect dynamic characteristics of the gear transmission system (GTS) but also indirectly influence dynamic behavior of the motor, which offers valuable insights into modeling integrated MGS and provides significant solutions for fault diagnosis within these systems. Full article

Transmission networks face continuous electrical and mechanical stresses due to increasing system challenges and power losses. Transmission networks require special focus and detailed studies each time a load or a generator emerges to the grid. The interline power flow controller (IPFC) is a relatively new scheme that is implemented in the transmission network to improve transmission efficiency, decrease transmission losses, and enhance voltage profile. In this paper, the interline power flow controller’s impact on transmission network performance is investigated as it is implemented within the IEEE 5-bus, 14-bus, and IEEE 57-bus systems. In addition, the whale optimization algorithm (WOA) is used to optimize the interline power flow controller locations within the system to achieve optimal transmission system performance. WOA performance is also compared to genetic algorithm (GA) and particle swarm optimization (PSO) algorithms, and the superiority of the proposed WOA-based control is proved. The robustness of the optimized system against load variations is investigated and the results introduced affirm the capability of the interline power flow controller to enhance transmission network efficiency. Full article

Frequency-selective surfaces (FSSs) have attracted great attention owing to their unique feature to manipulate transmission performance over the frequency domain. In this work, a filtering antenna-filtering antenna (FA-FA) FSS with a wide passband and double-side sharp roll-off characteristics is presented by inter-using the filtering antenna and receiving–transmitting metasurface methods. First, a dual-polarized filtering antenna element was designed by employing a parasitic band-stop structure with an L-probe feed. Then, the FA-FA-based FSS unit was constructed by placing two such filtering antennas back to back, with their feedings connected through metallic vias. Finally, the FSS with a wide passband and high selectivity was realized by arraying the FA-FA units periodically. The full-wave simulation results demonstrated that the designed FA-FA-based FSS had a wide passband from 13.06 GHz to 14.46 GHz with a flat in-band frequency response. The lower and upper roll-off bandwidths were sharp, reaching 1% and 1.2% of the center frequency. The proposed FA-FA-based FSS was fabricated and measured, achieving the coincident performance according to the theoretical prediction. The wideband band-pass FSS obtained a sharp double-side roll-off feature, which can be applied in various studies such as an antenna array, metasurface, communication, etc. Full article

Objective: Staphylococcus aureus (SA), including methicillin-resistant strains (MRSAs), is a major cause of skin and soft tissue infections (SSTIs) in military populations. This study investigated SSTI incidence and SA carriage in a military training site over 16 weeks using a prospective observational cohort design. Methods: Two training cohorts provided pre- and post-training self-collected swabs for bacterial carriage, and environmental swabs from accommodations, personal items, and training facilities. Hygiene awareness and practices were assessed through questionnaires. Bacteria were identified using culture, mass spectrometry (MALDI-TOF), and genomic sequencing. Results: Nasal carriage of SA increased from 19% to 49% by the end of training. SSTIs requiring treatment occurred in 16% of participants. Steam cleaning reduced but did not eliminate SA on personal bed linen. Additionally, 40% of participants had poor knowledge of antibacterial cleaning practices and wound management. Conclusions: Increased SA carriage was linked to human-to-human transmission in close-quarter military training environments. Implications for Public Health: Improved personal hygiene training, wound management education, and monitored cleaning protocols are essential to mitigate SSTI risks in communal military training environments. Full article