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Search Results (187)

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Keywords = ultra violet (UV)

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33 pages, 1800 KiB  
Review
Clean Label Approaches in Cheese Production: Where Are We?
by Jaime Fernandes, Sandra Gomes, Fernando H. Reboredo, Manuela E. Pintado, Olga Amaral, João Dias and Nuno Alvarenga
Foods 2025, 14(5), 805; https://doi.org/10.3390/foods14050805 - 26 Feb 2025
Cited by 1 | Viewed by 2670
Abstract
The Clean Label concept has gained significant traction in the cheese industry due to consumer preferences for minimally processed cheeses free from synthetic additives. This review explores different approaches for applying Clean Label principles to the cheese industry while maintaining food safety, sensory [...] Read more.
The Clean Label concept has gained significant traction in the cheese industry due to consumer preferences for minimally processed cheeses free from synthetic additives. This review explores different approaches for applying Clean Label principles to the cheese industry while maintaining food safety, sensory quality, and shelf life. Non-thermal technologies, such as high-pressure processing (HPP), pulsed electric fields (PEF), ultra-violet (UV), and visible light (VL), are among the most promising methods that effectively control microbial growth while preserving the nutritional and functional properties of cheese. Protective cultures, postbiotics, and bacteriophages represent microbiological strategies that are natural alternatives to conventional preservatives. Another efficient approach involves plant extracts, which contribute to microbial control, and enhance cheese functionality and potential health benefits. Edible coatings, either alone or combined with other methods, also show promising applications. Despite these advantages, several challenges persist: higher costs of production and technical limitations, possible shorter shelf-life, and regulatory challenges, such as the absence of standardized Clean Label definitions and compliance complexities. Further research is needed to develop and refine Clean Label formulations, especially regarding bioactive peptides, sustainable packaging, and advanced microbial control techniques. Addressing these challenges will be essential for expanding Clean Label cheese availability while ensuring product quality and maintaining consumer acceptance. Full article
(This article belongs to the Section Food Packaging and Preservation)
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16 pages, 7877 KiB  
Article
Effect of Extensive Solar Ultra-Violet Irradiation on the Durability of High-Density Polyethylene- and Polypropylene-Based Wood–Plastic Composites
by Mohammad N. Siddiqui, Halim H. Redhwi, Anthony L. Andrady, Sarfaraz A. Furquan and Syed Hussain
Polymers 2025, 17(1), 74; https://doi.org/10.3390/polym17010074 - 30 Dec 2024
Cited by 1 | Viewed by 893
Abstract
The natural and laboratory-accelerated weathering of wood–plastic composites (WPCs) based on high-density polyethylene (HDPE) and polypropylene (PP) plastics was investigated in this study. Injection molded samples of WPCs with different loadings of wood fiber ranging from 0 to 36 wt.% of wood were [...] Read more.
The natural and laboratory-accelerated weathering of wood–plastic composites (WPCs) based on high-density polyethylene (HDPE) and polypropylene (PP) plastics was investigated in this study. Injection molded samples of WPCs with different loadings of wood fiber ranging from 0 to 36 wt.% of wood were subjected to laboratory-accelerated weathering and natural weathering. The integrity of samples weathered to different extents was tested using a standard tensile test and surface hardness test to investigate the dependence of these properties on the duration of weathering exposure. Tensile data were used to identify the loading of wood fibers in either plastic matrix that afforded superior ultra-violet (UV) stability. Tensile measurements under uniaxial strain yielded average values of tensile strength (TS), low-extension modulus (E), and elongation at break (EB). Both natural weathering outdoors and accelerated weathering in the laboratory showed that the TS and EB decreased while the E increased with the duration of exposure for all samples tested. The change in the average TS of composites with the duration of exposure offers valuable insights. The correlation between the tensile and hardness data for the WPC samples was explored. After naturally weathering at two exposure sites, the hardness of the WPCs was found to decrease between 8% to 12.5%, depending on the composition and exposure location parameters. Furthermore, no marked difference in performance with increasing wood fiber beyond 18 wt.% was observed. WPCs can be a key parameter in environmental sustainability by being used in the building and packaging industries, which reduces carbon emissions and waste generation. Full article
(This article belongs to the Section Polymer Composites and Nanocomposites)
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13 pages, 3345 KiB  
Article
Enhancement of Anti-UV Aging Performance of Asphalt Modified by UV-531/Pigment Violet Composite Light Stabilizers
by Fa Zhang, Yang Liu, Zhenhao Cao, Yifan Liu, Yufang Ren, Haishan Liang, Kunyu Wang, Yanyan Zhang, Jia Wang and Xue Li
Processes 2024, 12(12), 2758; https://doi.org/10.3390/pr12122758 - 4 Dec 2024
Cited by 1 | Viewed by 1034
Abstract
Ultraviolet (UV) radiation accelerates the aging of asphalt pavements and shortens the service life of the pavement. To effectively mitigate the impact of UV aging on asphalt performance, a novel composite anti-UV aging agent, 2-hydroxy-4-n-octyoxybenzophenone/pigment violet (UV-531/PV), was developed. After UV-accelerated aging, the [...] Read more.
Ultraviolet (UV) radiation accelerates the aging of asphalt pavements and shortens the service life of the pavement. To effectively mitigate the impact of UV aging on asphalt performance, a novel composite anti-UV aging agent, 2-hydroxy-4-n-octyoxybenzophenone/pigment violet (UV-531/PV), was developed. After UV-accelerated aging, the modified asphalt samples were characterized by conventional performance tests, Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and a dynamic shear rheometer (DSR). The results show that UV-531/PV-composite-modified asphalt maintains excellent conventional properties after UV aging. The FTIR testing showed that the changes in carbonyl index (Ic=o) and sulfoxide index (Is=o) of the composite-modified asphalt were significantly smaller than those of the matrix asphalt, indicating the less oxidation degree of the composite-modified asphalt. The GPC test results showed that the change in molecular weight of the composite-modified asphalt after UV aging was less than that of the matrix asphalt. DSR results showed that UV-531/PV-modified asphalt exhibited higher viscoelasticity and higher rutting resistance than unmodified asphalt. This study proposes a new method for preparing anti-UV aging asphalt, which can be used for micro-surfacing, fog sealing or ultra-thin overlay on road surfaces. Full article
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23 pages, 4869 KiB  
Article
UV Solar Energy and Erythemal Exposure: Mathematical Models to Assess the Dose on Vertical and Inclined Planes in Different Sky Conditions
by Chiara Burattini, Massimo Borra, Flavia Vespasiano and Fabio Bisegna
Energies 2024, 17(22), 5718; https://doi.org/10.3390/en17225718 - 15 Nov 2024
Cited by 1 | Viewed by 896
Abstract
Ultra violet (UV) solar energy can cause several negative effects to the skin and eyes in case of overexposure. To protect people from erythemal damage, personal erythemal exposure must be carefully assessed when outdoor activities are carried out. The direct measure with scientific [...] Read more.
Ultra violet (UV) solar energy can cause several negative effects to the skin and eyes in case of overexposure. To protect people from erythemal damage, personal erythemal exposure must be carefully assessed when outdoor activities are carried out. The direct measure with scientific instruments is impracticable to common people, and indirect methods assess the exposure only on the horizontal plane: this work developed a mathematical model to assess erythemal exposure to all the body districts. UVA irradiance and erythemal irradiance were measured on several inclined planes, oriented to the four cardinal directions, in seven environments with multiple sky conditions. The UV erythemal (UVE) ratio between erythemal irradiance on an inclined plane (Iery°) and UVA irradiance on a horizontal plane (IUVAh) was calculated. The results indicate that the UVE = Iery°/IUVAh is variable across the day and depends on the plane orientation, its degree of inclination, and sky conditions. Mathematical models to calculate erythemal exposure in clear, intermediate and overcast sky conditions on planes with different inclinations and orientations were derived from the daily trends of the UVE = Iery°/IUVAh. The application procedure of the mathematical model to the vertical plane oriented to the south is provided as an example. Full article
(This article belongs to the Section B1: Energy and Climate Change)
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21 pages, 5849 KiB  
Article
Synthesis and Evaluation of a ZnO-Chitosan Adduct for Safe and Sustainable Enhanced Ultra-Violet (UV) Sunscreens Protection
by Mattia Battistin, Alessandro Bonetto, Francesco Nicoli, Elena Torreggiani, Andrea Brunetta, Elena Cesa, Stefano Manfredini, Anna Baldisserotto and Silvia Vertuani
Molecules 2024, 29(21), 5204; https://doi.org/10.3390/molecules29215204 - 3 Nov 2024
Viewed by 2142
Abstract
Chitosan (Ch), a natural polysaccharide, is known for its biocompatibility, biodegradability, and various beneficial properties, including antioxidant and antibacterial activities. The objective of this study is to investigate the functionalization of zinc oxide (ZnO) with chitosan to develop a novel ZnO@Ch adduct for [...] Read more.
Chitosan (Ch), a natural polysaccharide, is known for its biocompatibility, biodegradability, and various beneficial properties, including antioxidant and antibacterial activities. The objective of this study is to investigate the functionalization of zinc oxide (ZnO) with chitosan to develop a novel ZnO@Ch adduct for use in cosmetic formulations, specifically as a sun protection agent. The functionalization was achieved through ionotropic gelation, which enhanced the stability and reduced the photocatalytic activity of ZnO, thereby improving its safety profile for skin applications. FTIR spectroscopy confirmed the successful functionalization, while TGA and DSC characterized the thermal properties and stability. The Zeta potential and particle size analyses demonstrated improved stability of ZnO@Ch across various pH levels compared to uncoated ZnO. The structure of the obtained adduct was also confirmed by SEM analysis. The ZnO@Ch adduct exhibited enhanced stability at neutral and slightly alkaline pH values, reduced photocatalytic activity compared to pure ZnO, and had lower cytotoxicity in 3T3 cells compared to pure ZnO, particularly at higher concentrations. The ZnO@Ch adduct provided a higher Sun Protection Factor (SPF) and UVA Protection Factor (UVA-PF) than pure ZnO, indicating enhanced UV protection. The adduct’s ability to provide higher SPF at lower ZnO concentrations offers economic and environmental benefits, aligning with sustainable product design principles. Future studies will focus on optimizing the formulation and testing the efficacy and safety at higher concentrations to fully realize its potential as a natural, eco-friendly sunscreen ingredient. Full article
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20 pages, 3186 KiB  
Article
Characterization of Novel Exopolysaccharides from Weissella cibaria and Lactococcus lactis Strains and Their Potential Application as Bio-Hydrocolloid Agents in Emulsion Stability
by Amal Zammouri, Manel Ziadi, Adem Gharsallaoui, Imen Fguiri, Imed Sbissi, Mohamed Hammadi and Touhami Khorchani
Fermentation 2024, 10(10), 532; https://doi.org/10.3390/fermentation10100532 - 20 Oct 2024
Cited by 2 | Viewed by 1903
Abstract
The aim of the present study was the isolation of high exopolysaccharide (EPS) producers, Lactic Acid Bacteria (LAB) strains, from three types of milk: goat, sheep, and camel milk. Among 112 LAB isolates tested for their ability to produce EPS on MRS-sucrose agar, [...] Read more.
The aim of the present study was the isolation of high exopolysaccharide (EPS) producers, Lactic Acid Bacteria (LAB) strains, from three types of milk: goat, sheep, and camel milk. Among 112 LAB isolates tested for their ability to produce EPS on MRS-sucrose agar, only 11 strains were able to produce EPS and only three higher producers’ strains were identified by 16S rRNA gene sequencing as two strains of Lactococcus lactis subsp. lactis (SP255, SP257) isolated from camel milk and one strain of Weissella cibaria (SP213) isolated from goat milk. The physicochemical characterization of the purified EPSs revealed a significant sugar yield, with concentrations ranging from 2.17 to 2.77 g/L, while the protein content remained relatively low (0.03 g/L). The UV-visible spectrum showed high Ultra Violet (UV) absorption at 240–280 nm and the Fourier-Transform Infrared (FTIR) spectra showed the presence of a large number of functional groups, including hydroxyl (-OH), carbonyl (-C=O), and methyl groups (-CH3). The EPS solubility indicated their hydrophilic properties and the investigation of interfacial properties indicated that these EPSs could be used as natural emulsifiers and stabilizers in both acidic and neutral emulsions. Moreover, a new type of emulsion system was developed by the utilization of EPSs in the formation of multilayer interfaces in oil-in-water (O/W) emulsions stabilized by sodium caseinate (CAS). Thus, the impact of an EPS addition on the particle size distribution and electrical charge has been studied. At pH 3, the studied EPSs adhered to the surfaces of caseinate-coated droplets and the stability of O/W emulsions was improved by adding certain concentrations of EPSs. The minimum concentration required to stabilize multilayer emulsions for EPSs SP255, EPS SP257, and EPS SP213 was 1.5, 1.5, and 1.7 g/L, respectively. These findings reveal a new EPS with significant potential for industrial use, particularly as an emulsion stabilizer. Full article
(This article belongs to the Section Fermentation for Food and Beverages)
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10 pages, 3427 KiB  
Article
High-Throughput Drug Stability Assessment via Biomimetic Metalloporphyrin-Catalyzed Reactions Using Laser-Assisted Rapid Evaporative Ionization Mass Spectrometry (LA-REIMS)
by András Marton, Zsombor Mohácsi, Balázs Decsi, Balázs Csillag, Júlia Balog, Richard Schäffer, Tamás Karancsi and György Tibor Balogh
Pharmaceutics 2024, 16(10), 1266; https://doi.org/10.3390/pharmaceutics16101266 - 27 Sep 2024
Cited by 1 | Viewed by 1266
Abstract
Background: Building extensive drug candidate libraries as early in the development pipeline as possible, with high-throughput in vitro absorption, distribution, metabolism, and excretion (ADME) profiling, is crucial for the selection of lead compounds to guide subsequent research and production phases. Traditionally, the analysis [...] Read more.
Background: Building extensive drug candidate libraries as early in the development pipeline as possible, with high-throughput in vitro absorption, distribution, metabolism, and excretion (ADME) profiling, is crucial for the selection of lead compounds to guide subsequent research and production phases. Traditionally, the analysis of metabolic stability assays heavily relies on high-throughput LC-MS/MS (liquid chromatography tandem mass spectrometry) techniques to meet with the lead profiling demands. Laser-assisted rapid evaporative ionization mass spectrometry (LA-REIMS) is a quick and efficient technique for characterizing complex biological samples without laborious sample preparation. Objective: In this study, using an automated LA-REIMS well plate reader, achieving an 8 s per sample measurement time, the oxidative metabolic stability of active drug agents was assessed using biomimetic metalloporphyrin-based oxidative model reactions. Results: The results obtained using the novel LA-REIMS-based protocol were compared to and corroborated by those obtained using conventional HPLC-UV-MS (high performance liquid chromatography with ultra-violet detection coupled with mass spectrometry) measurements. Conclusions: LA-REIMS emerges as a promising technique, demonstrating potential suitability for semi-quantitative high-throughput metabolic stability in an optimized solvent environment. Full article
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15 pages, 4386 KiB  
Article
POSS and PAG Dual-Containing Chemically Amplified Photoresists by RAFT Polymerization for Enhanced Thermal Performance and Acid Diffusion Inhibition
by Haimeng Yu, Shaoshuai Liu, Haiyan Fu, Zepeng Cui, Liangshun Zhang and Jia Tian
Appl. Sci. 2024, 14(17), 7722; https://doi.org/10.3390/app14177722 - 2 Sep 2024
Cited by 3 | Viewed by 5072
Abstract
A random copolymer (PTBM), utilized as deep ultra-violet (DUV) photoresist, was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization with tert-butyl methacrylate (tBMA), methyl methacrylate (MMA), triphenylsulfonium p-styrenesulfonate (TPS-SS), and functional poly (sesquicarbonylsiloxanes) (POSS-MA) as the monomer components, and 4-cyano-4-[(dodecylsulfanylthiocarbonyl) sulfanyl]pentanoic acid [...] Read more.
A random copolymer (PTBM), utilized as deep ultra-violet (DUV) photoresist, was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization with tert-butyl methacrylate (tBMA), methyl methacrylate (MMA), triphenylsulfonium p-styrenesulfonate (TPS-SS), and functional poly (sesquicarbonylsiloxanes) (POSS-MA) as the monomer components, and 4-cyano-4-[(dodecylsulfanylthiocarbonyl) sulfanyl]pentanoic acid (CDSPA) as the RAFT reagent. Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (1H NMR) proved successful synthesis. Ultraviolet absorption spectroscopy (UV) analysis verified the transparency of the polymer in the DUV band. RAFT polymerization kinetics showed that the polymerization rate conformed to the first-order kinetic relationship, and the polymerization process exhibited a typical controlled free radical polymerization behavior. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and static thermo-mechanical analysis (TMA) showed that the incorporation of POSS groups improved the thermal properties of the copolymer. According to scanning electron microscopy (SEM) images, the copolymerization of photoacid monomers (TPS-SS) resulted in photoresist copolymers exhibiting good resistance to acid diffusion and low roughness. Full article
(This article belongs to the Section Applied Thermal Engineering)
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21 pages, 8190 KiB  
Article
Effect of Melamine Formaldehyde Resin Encapsulated UV Acrylic Resin Primer Microcapsules on the Properties of UV Primer Coating
by Yuming Zou, Yongxin Xia and Xiaoxing Yan
Polymers 2024, 16(16), 2308; https://doi.org/10.3390/polym16162308 - 15 Aug 2024
Cited by 9 | Viewed by 1564
Abstract
Ultra-Violet (UV) coatings are widely adaptable of substrates and produce low emissions of volatile organic compounds. UV coatings can extend service life by adding self-healing microcapsules that restore integrity after sustaining damage. In this study, UV coating was used as a core material; [...] Read more.
Ultra-Violet (UV) coatings are widely adaptable of substrates and produce low emissions of volatile organic compounds. UV coatings can extend service life by adding self-healing microcapsules that restore integrity after sustaining damage. In this study, UV coating was used as a core material; microcapsules were produced and added to the UV coating to enhance its self-healing property, providing a good protection for both the UV coating and the substrate. UV primer microcapsules were prepared with UV primer as the core material and melamine formaldehyde resin as the wall material. The UV primer containing more than 98.0% solids content was mainly composed of epoxy acrylic resin, polyester acrylic resin, trihydroxy methacrylate, trimethyl methacrylate, and photo initiator. The preparation process of the UV primer microcapsules was optimized. Further, the UV coating was prepared with better UV primer microcapsules, and the effects of the UV primer microcapsules alongside the comprehensive properties of the coating were studied. The best preparation process for the UV primer microcapsules was as follows: the wall-core mass ratio was 1:0.50, Triton X-100 and Span-20 as emulsifiers with an HLB value of 10.04, the microcapsule reaction temperature was 70 °C, and the reaction time of the was 3.0 h. When the quantity of the UV primer microcapsules increased in the coating, color difference ΔE of the coating increased, gloss decreased, transmittance decreased, elongation at break increased and then decreased, roughness increased, and self-healing rate first increased and then decreased. When the addition of the UV primer microcapsules reached 2.0%, the color difference ΔE of the coating was 1.71, the gloss was 106.63 GU, the transmittance was 78.80%, the elongation at break was 3.62%, the roughness was 0.204 μm, and the self-healing rate was 28.56%, which were the best comprehensive properties of the UV primer. To improve the comprehensive properties of the UV coatings, the UV coatings were modified by a microcapsule technology, which gave the UV coatings a better self-healing property. The application range of microcapsules for the UV coatings was broadened. Based on the previous research of microcapsules in UV coatings, the results further refined the study of the effects of adding self-healing microcapsules to UV coatings using the UV coating itself as the core material. Full article
(This article belongs to the Special Issue Recent Advances in Polymer Composites for Functional Applications)
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32 pages, 1987 KiB  
Review
Mitochondrial Reactive Oxygen Species in Infection and Immunity
by Arunima Mukherjee, Krishna Kanta Ghosh, Sabyasachi Chakrabortty, Balázs Gulyás, Parasuraman Padmanabhan and Writoban Basu Ball
Biomolecules 2024, 14(6), 670; https://doi.org/10.3390/biom14060670 - 8 Jun 2024
Cited by 26 | Viewed by 7006
Abstract
Reactive oxygen species (ROS) contain at least one oxygen atom and one or more unpaired electrons and include singlet oxygen, superoxide anion radical, hydroxyl radical, hydroperoxyl radical, and free nitrogen radicals. Intracellular ROS can be formed as a consequence of several factors, including [...] Read more.
Reactive oxygen species (ROS) contain at least one oxygen atom and one or more unpaired electrons and include singlet oxygen, superoxide anion radical, hydroxyl radical, hydroperoxyl radical, and free nitrogen radicals. Intracellular ROS can be formed as a consequence of several factors, including ultra-violet (UV) radiation, electron leakage during aerobic respiration, inflammatory responses mediated by macrophages, and other external stimuli or stress. The enhanced production of ROS is termed oxidative stress and this leads to cellular damage, such as protein carbonylation, lipid peroxidation, deoxyribonucleic acid (DNA) damage, and base modifications. This damage may manifest in various pathological states, including ageing, cancer, neurological diseases, and metabolic disorders like diabetes. On the other hand, the optimum levels of ROS have been implicated in the regulation of many important physiological processes. For example, the ROS generated in the mitochondria (mitochondrial ROS or mt-ROS), as a byproduct of the electron transport chain (ETC), participate in a plethora of physiological functions, which include ageing, cell growth, cell proliferation, and immune response and regulation. In this current review, we will focus on the mechanisms by which mt-ROS regulate different pathways of host immune responses in the context of infection by bacteria, protozoan parasites, viruses, and fungi. We will also discuss how these pathogens, in turn, modulate mt-ROS to evade host immunity. We will conclude by briefly giving an overview of the potential therapeutic approaches involving mt-ROS in infectious diseases. Full article
(This article belongs to the Special Issue Mitochondrial ROS in Health and Disease)
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1 pages, 127 KiB  
Abstract
Synthesis and Characterization of Graphitic Carbon Nitride (g-C3N4)/Zinc Oxide Hybrid Nanocomposites for Photocatalytic and Biomedical Application
by Suneel and Qazi Inamur Rahman
Proceedings 2024, 103(1), 33; https://doi.org/10.3390/proceedings2024103033 - 12 Apr 2024
Viewed by 774
Abstract
Graphitic carbon nitride (g-C3N4) and zinc oxide (ZnO) are two promising materials that have been extensively studied for their potential applications in the photocatalytic and biomedical fields, including biosensors, bioimaging, photodynamic therapy, and antimicrobials, because of its biocompatible nature. [...] Read more.
Graphitic carbon nitride (g-C3N4) and zinc oxide (ZnO) are two promising materials that have been extensively studied for their potential applications in the photocatalytic and biomedical fields, including biosensors, bioimaging, photodynamic therapy, and antimicrobials, because of its biocompatible nature. The synthesis of g-C3N4/ZnO nanocomposites will be achieved through hydrothermal synthesis to produce materials with enhanced photocatalytic and biomedical properties due to the development of heterojunctions. The synthesized g-C3N4/ZnO hybrid nanostructures have a band gap of around 2.85 eV to 3.01 eV. The photocatalytic activity of the composites is evaluated through the degradation of organic pollutants (MB, RB171, RhB dyes) under simulated solar irradiation, demonstrating their potential for environmental remediation. In biomedical applications, the g-C3N4/ZnO nanocomposites exhibit biocompatibility and are explored for use in antimicrobial coatings. Techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and UV–Vis(ultra-violet visible) spectroscopy are employed to analyze the crystal structure, surface morphology, particle size, chemical composition, and optical properties of the composites. The comprehensive characterization of these materials is crucial for their successful development and utilization in various technological domains. Full article
(This article belongs to the Proceedings of The 3rd International Electronic Conference on Biomolecules)
22 pages, 5203 KiB  
Article
Nanocomposite-Supported Polymeric Composites Prepared with Different Deposition Bases: Characterization and Application in X-ray Shielding
by Shaymaa Mohammed Fayyadh and Ali Ben Ahmed
Physics 2024, 6(1), 334-355; https://doi.org/10.3390/physics6010022 - 4 Mar 2024
Cited by 1 | Viewed by 1503
Abstract
This study deals with the preparation of magnetite nanoparticles (NPs) via a coprecipitation method using several precipitation bases: binary precipitator (NH4OH), mono precipitator (NaOH), and weak precipitator (Ca(OH)2). The prepared magnetite NPs were identified using X-ray diffraction (XRD), transmission [...] Read more.
This study deals with the preparation of magnetite nanoparticles (NPs) via a coprecipitation method using several precipitation bases: binary precipitator (NH4OH), mono precipitator (NaOH), and weak precipitator (Ca(OH)2). The prepared magnetite NPs were identified using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, surface area analysis, magnetic properties, Fourier-transformed infrared spectra (FT-IR), and ultra-violet UV–visible spectra. As a result, the phases of the produced magnetite NPs were unaffected by the use of various bases, but their crystallite sizes were affected. It was found that the binary base provided the smallest crystallite size, the mono base provided an average size, and the weak base provided the largest crystallite size. The UV–visible absorption spectroscopy investigation revealed that the absorption and the energy gap rose with a reduction in nanoparticle size. The prepared magnetite NPs were used to manufacture polymeric-based nanocomposites employed as protective shields from low-energy X-rays that are light in weight. These samples were identified using XRD, atomic force microscopy (AFM), and FT-IR spectroscopy. The crystallite size was slightly larger than it was in the case of magnetite NPs. This is consistent with the results of AFM. The interference between the two phases was observed in the results of the FT-IR spectra. The effects of the size of the magnetite NPs on the attenuation tests, linear attenuation coefficient, mass attenuation coefficient, half-value layer, and mean free path were investigated. The results showed that the efficiency of using manufactured shields increases with the decrease in the NPs size of the magnetite used as a reinforcement phase for a range of low operating voltages. Full article
(This article belongs to the Section Applied Physics)
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11 pages, 3016 KiB  
Article
Enhancement of the Visible Light Photodetection of Inorganic Photodiodes via Additional Quantum Dots Layers
by Seong Jae Kang, Jun Hyung Jeong, Jin Hyun Ma, Min Ho Park, Hyoun Ji Ha, Jung Min Yun, Yu Bin Kim and Seong Jun Kang
Micromachines 2024, 15(3), 318; https://doi.org/10.3390/mi15030318 - 25 Feb 2024
Viewed by 1753
Abstract
Visible light photodetectors are extensively researched with transparent metal oxide holes/electron layers for various applications. Among the metal oxide transporting layers, nickel oxide (NiO) and zinc oxide (ZnO) are commonly adopted due to their wide band gap and high transparency. The objective of [...] Read more.
Visible light photodetectors are extensively researched with transparent metal oxide holes/electron layers for various applications. Among the metal oxide transporting layers, nickel oxide (NiO) and zinc oxide (ZnO) are commonly adopted due to their wide band gap and high transparency. The objective of this study was to improve the visible light detection of NiO/ZnO photodiodes by introducing an additional quantum dot (QD) layer between the NiO and ZnO layers. Utilizing the unique property of QDs, we could select different sizes of QDs and responsive light wavelength ranges. The resulting red QDs utilized device that could detect light starting at 635 nm to UV (Ultra-violet) light wavelength and exhibited a photoresponsivity and external quantum efficiency (EQE) of 14.99 mA/W and 2.92% under 635 nm wavelength light illumination, respectively. Additionally, the green QDs, which utilized a device that could detect light starting at 520 nm, demonstrated photoresponsivity values of 8.34 mA/W and an EQE of 1.99% under 520 nm wavelength light illumination, respectively. In addition, we used X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) to investigate the origin of the photocurrents and the enhancement of the device’s performance. This study suggests that incorporating QDs with metal oxide semiconductors is an effective approach for detecting visible light wavelengths in transparent optoelectronic devices. Full article
(This article belongs to the Special Issue Fabrication and Application of Optoelectronics Based on Nanomaterials)
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17 pages, 6239 KiB  
Article
Characterizing and Removing Ultra-Violet Contamination in Ion Observations on Board Tianwen-1
by Limin Wang, Lei Li, Wenya Li, Linggao Kong, Binbin Tang, Jijie Ma, Yiteng Zhang, Lianghai Xie, Aibing Zhang, Fuhao Qiao, Peter Wurz and André Galli
Atmosphere 2024, 15(1), 19; https://doi.org/10.3390/atmos15010019 - 23 Dec 2023
Viewed by 1535
Abstract
The Mars Ion and Neutral Particle Analyzer (MINPA) onboard Tianwen-1 aims to study the interaction between Mars and the solar wind via in situ ion measurement and energetic neutral atom imaging. Despite the efforts for Ultra-Violet suppression in MINPA design, 0.48% of ion [...] Read more.
The Mars Ion and Neutral Particle Analyzer (MINPA) onboard Tianwen-1 aims to study the interaction between Mars and the solar wind via in situ ion measurement and energetic neutral atom imaging. Despite the efforts for Ultra-Violet suppression in MINPA design, 0.48% of ion observations from November 2021 to July 2022 were identified as UV-contaminated. The UV emissions primarily penetrate into the instrument through the ENA entrance. Statistically, the distribution of the UV contamination in phase space typically spans 3 to 4 azimuth sectors. The contamination is uniformly distributed across the polar dimension while, in the energy and mass dimensions, it is proportional to the time-of-flight duration. Comparisons between the in-flight performance and ground calibration suggest that azimuthal broadening and intensity variations of the contamination may result from differing responses across the azimuthal sectors. Based on the characteristics of the UV impact on MINPA ion observations, a removal algorithm is proposed to reduce contamination while preserving valid signals, which improves the data quality effectively and benefits the interpretation of MINPA’s ion measurements in the Martian space environment. The cause, effect, and distribution of the UV contamination obtained by this study may serve as a reference for other space ion observations. Full article
(This article belongs to the Section Planetary Atmospheres)
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14 pages, 3390 KiB  
Article
Green Synthesis of Copper Oxide Nanoparticles from the Leaves of Aegle marmelos and Their Antimicrobial Activity and Photocatalytic Activities
by Syed Ghazanfar Ali, Uzma Haseen, Mohammad Jalal, Rais Ahmad Khan, Ali Alsalme, Hilal Ahmad and Haris Manzoor Khan
Molecules 2023, 28(22), 7499; https://doi.org/10.3390/molecules28227499 - 9 Nov 2023
Cited by 22 | Viewed by 3846
Abstract
The leaves of the Aegle marmelos plant were used for the green synthesis of copper oxide nanoparticles and further characterized by different techniques, including (Ultra Violet-Visible) UV-Vis, Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), Transmission electron microscopy (TEM) and X-ray diffraction (XRD). [...] Read more.
The leaves of the Aegle marmelos plant were used for the green synthesis of copper oxide nanoparticles and further characterized by different techniques, including (Ultra Violet-Visible) UV-Vis, Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), Transmission electron microscopy (TEM) and X-ray diffraction (XRD). The UV-Vis showed a peak at 330 nm, which may be due to the Surface Plasmon Resonance phenomenon. XRD analysis showed the crystalline nature of copper oxide nanoparticles (CuO NPs). In contrast, SEM showed that nanoparticles were not aggregated or clumped, EDX showed the presence of elemental copper., and further, the TEM analysis revealed the average particle size of copper oxide nanoparticles to be 32 nm. The Minimum Inhibitory Concentration (MIC) for Escherichia coli (E. coli) and Staphylococcusaureus (S. aureus) was found to be 400 µg/mL, whereas for Candida albicans (C. albicans) and Candida dubliniensis (C. dubliniensis) it was 800 µg/mL. The zone of inhibition in the well diffusion assay showed the antimicrobial activity of copper oxide nanoparticles, and it also showed that as the concentration of copper oxide nanoparticles increased, the zone of inhibition also increased. Further, the electron microscopic view of the interaction between copper oxide nanoparticles and C. albicans cells showed that CuO NPs were internalized and attached to the cell membrane, which caused changes in the cellular structure and caused deformities which eventually led to cell death. The prepared CuO NPs showed significant photocatalytic degradation of organic dyes in the presence of sunlight. Full article
(This article belongs to the Special Issue Synthesis and Application of Nanoparticles and Nanocomposites)
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