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Search Results (1,264)

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Keywords = UV-absorbing

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8 pages, 2685 KiB  
Proceeding Paper
Dye Decolorization Under Visible Light Irradiation Using Bismuth Subcarbonate
by Kentaro Yamauchi, Mai Furukawa, Ikki Tateishi, Hideyuki Katsumata and Satoshi Kaneco
Chem. Proc. 2025, 17(1), 5; https://doi.org/10.3390/chemproc2025017005 - 4 Aug 2025
Abstract
Commercially available bismuth subcarbonate (Bi2O2CO3) was treated with nitric acid and the surfactant cetyltrimethylammonium bromide. The treated catalysts exhibited enhanced photocatalytic activity compared to pure Bi2O2CO3 in the decolorization of rhodamine B [...] Read more.
Commercially available bismuth subcarbonate (Bi2O2CO3) was treated with nitric acid and the surfactant cetyltrimethylammonium bromide. The treated catalysts exhibited enhanced photocatalytic activity compared to pure Bi2O2CO3 in the decolorization of rhodamine B (RhB) under visible light irradiation. The absorbance at 554 nm gradually decreased over time and disappeared completely within 80 min. The crystal structure, morphology, and optical properties of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. The improved photocatalytic activity of the treated catalysts was attributed to partial carbonate removal and the formation of Bi5+ species. Scavenger experiments indicated that superoxide radicals (·O2) and photogenerated holes (h+) played significant roles in the photocatalytic decolorization of RhB. Full article
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14 pages, 752 KiB  
Article
Versatile High-Performance Liquid Chromatography and Ultraviolet Detection-Based Method for the Determination of Thioproline in Pharmaceutical and Cosmetic Products
by Marta Gaweł, Martyna Płodzik, Rafał Głowacki and Justyna Piechocka
Molecules 2025, 30(15), 3152; https://doi.org/10.3390/molecules30153152 - 28 Jul 2025
Viewed by 265
Abstract
The article presents the first method based on high-performance liquid chromatography and ultraviolet detection (HPLC-UV) for the determination of timonacic (thioproline, 1,3-thiazolidine-4-carboxylic acid, tPro) in pharmaceutical tablets and face care products (creams, sera, foundations, suncreams). Sample preparation primarily involves solid-liquid extraction (SLE) of [...] Read more.
The article presents the first method based on high-performance liquid chromatography and ultraviolet detection (HPLC-UV) for the determination of timonacic (thioproline, 1,3-thiazolidine-4-carboxylic acid, tPro) in pharmaceutical tablets and face care products (creams, sera, foundations, suncreams). Sample preparation primarily involves solid-liquid extraction (SLE) of tPro with 0.2 mol/L phosphate buffer pH 6, derivatization with 0.25 mol/L 2-chloro-1-methylquinolinium tetrafluoroborate (CMQT), followed by polytetrafluoroethylene (PTFE) membrane filtration. The chromatographic separation of the stable UV-absorbing 2-S-quinolinium derivative is achieved within 14 min at 25 °C on a Zorbax SB-C18 (150 × 4.6 mm, 5 µm) column using gradient elution. The eluent consists of 0.1 mol/L trichloroacetic acid (TCA), pH 1.7, in a mixture with acetonitrile (ACN) delivered at a flow rate of 1 mL/min. The analyte is quantified by monitoring at 348 nm. The assay linearity was observed within 0.5–125 μmol/L. The limit of quantification (LOQ) was found to be 0.5 μmol/L. The accuracy ranged from 93.22% to 104.31% and 97.38% to 103.48%, while precision varied from 0.30% to 11.23% and 1.13% to 9.64% for intra- and inter-assay measurements, respectively. The method was successfully applied to commercially available on the Polish market pharmaceutical and cosmetic products. Full article
(This article belongs to the Special Issue Recent Advances in Chromatography for Pharmaceutical Analysis)
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14 pages, 888 KiB  
Article
Environmental Impact of Biodegradable Packaging Based on Chia Mucilage in Real Water Bodies
by Renata Machado Pereira da Silva, Stefanny Pereira Atanes and Sibele Santos Fernandes
Processes 2025, 13(8), 2381; https://doi.org/10.3390/pr13082381 - 27 Jul 2025
Viewed by 301
Abstract
The intense demand for alternatives to conventional plastics has increasingly motivated the development of biodegradable packaging. However, the ecological impact of these materials when discarded in natural settings has not yet been evaluated. Therefore, this study investigated the effects of films based on [...] Read more.
The intense demand for alternatives to conventional plastics has increasingly motivated the development of biodegradable packaging. However, the ecological impact of these materials when discarded in natural settings has not yet been evaluated. Therefore, this study investigated the effects of films based on chia mucilage in different aquatic environments. The solubilization time varied according to water type, ranging from 40 min in ultrapure, deionized, and distilled water to 230 min in saline water. After solubilization, all water samples exhibited increased turbidity (from 1.04 to 15.73 NTU in deionized water) and apparent color (from 0 to 44 PCU in deionized water) as well as pH variations depending on ionic strength. Deionized water also showed the highest viscosity increase (>350 Pa·s at 1 s−1). UV–Vis spectra revealed a moderate rise in absorbance between 236 and 260 nm, indicating organic compound release. Regarding phytotoxicity, the solubilized films had no toxic effect and promoted a biostimulating effect on root elongation, with Relative Germination Index values exceeding 140% in most samples. These results reinforce the potential of chia-based films for controlled disposal, particularly in low-salinity environments, while highlighting the importance of evaluating post-solubilization interactions with aquatic systems. Full article
(This article belongs to the Special Issue Advances in Waste Management and Treatment of Biodegradable Waste)
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12 pages, 3396 KiB  
Article
The Influence of Precursor pH on the Synthesis and Morphology of AuNPs Synthesized Using Green Tea Leaf Extract
by Oksana Velgosova, Zuzana Mikulková and Maksym Lisnichuk
Crystals 2025, 15(8), 682; https://doi.org/10.3390/cryst15080682 - 26 Jul 2025
Viewed by 214
Abstract
This study investigates the effect of precursor pH (1.3, 2, 4, 6, 8, and 10) on the synthesis of gold nanoparticles (AuNPs) via a green synthesis approach using an aqueous extract of green tea (Camellia sinensis) leaves. The formation of AuNPs [...] Read more.
This study investigates the effect of precursor pH (1.3, 2, 4, 6, 8, and 10) on the synthesis of gold nanoparticles (AuNPs) via a green synthesis approach using an aqueous extract of green tea (Camellia sinensis) leaves. The formation of AuNPs was monitored using UV-vis spectrophotometry and confirmed using transmission electron microscopy (TEM). The results confirmed that the morphology and size of the AuNPs are strongly dependent on the pH of the reaction medium. Based on spectral features, the color of the colloids, and TEM analysis, the synthesized samples were classified into three groups. The first (pH 8 and 10) contained predominantly spherical nanoparticles with an average diameter of ~18 nm, the second (pH 1.3 and 2) contained different shaped nanoparticles (20–250 nm in diameter), and the third (pH 4 and 6) contained flower-like nanostructures with a mean diameter of ~60 nm. UV-vis analysis revealed good stability of all AuNP colloids, except at pH 1.3, where a significant decrease in absorbance intensity over time was observed. These findings confirm that tuning the precursor pH allows for controlled manipulation of nanoparticle morphology and stability in green synthesis systems. Full article
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15 pages, 3673 KiB  
Article
Photodegradation Assessment of Calcipotriol in the Presence of UV Absorbers by UHPLC/MSE
by Małgorzata Król, Paweł Żmudzki, Adam Bucki and Agata Kryczyk-Poprawa
Appl. Sci. 2025, 15(15), 8124; https://doi.org/10.3390/app15158124 - 22 Jul 2025
Viewed by 355
Abstract
Calcipotriol, a synthetic vitamin D3 analogue widely used in psoriasis treatment, requires a detailed stability assessment due to its topical application and potential exposure to UV radiation. As a drug applied directly to the skin, calcipotriol is particularly susceptible to photodegradation, which [...] Read more.
Calcipotriol, a synthetic vitamin D3 analogue widely used in psoriasis treatment, requires a detailed stability assessment due to its topical application and potential exposure to UV radiation. As a drug applied directly to the skin, calcipotriol is particularly susceptible to photodegradation, which may affect its therapeutic efficacy and safety profile. The present study focuses on the analysis of calcipotriol photostability. An advanced UHPLC/MSE method was employed for the precise determination of calcipotriol and its degradation products. Particular attention was given to the effects of commonly used organic UV filters—approved for use in cosmetic products in both Europe and the USA (benzophenone-3, dioxybenzone, meradimate, sulisobenzone, homosalate, and avobenzone)—on the stability of calcipotriol. Unexpected degradation of calcipotriol was observed in the presence of sulisobenzone. Importantly, this effect was consistently detected in methanolic solution and in the pharmaceutical formulation containing calcipotriol and betamethasone, which is particularly significant from a practical perspective. This finding underscores the necessity of evaluating photostability under real-life conditions, as cosmetic ingredients, when co-applied with topical drugs on the skin, may substantially influence the stability profile of the pharmaceutical active ingredient. The research resulted in the first-time characterization of four degradation products of calcipotriol. The degradation process was found to primarily affect the E-4-cyclopropyl-4-hydroxy-1-methylbut-2-en-1-yl moiety, causing its isomerization to the Z isomer and the formation of diastereomers with either the R or S configuration. Computational analyses using the OSIRIS Property Explorer indicated that none of the five degradation products exhibit a toxicity effect, whereas molecular docking studies suggested possible binding of two of the five degradation products of calcipotriol with the VDR. Full article
(This article belongs to the Section Chemical and Molecular Sciences)
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16 pages, 5026 KiB  
Article
Insulation Ability and Morphological Effect of ZrO2 Spacer Layer in Carbon-Based Multiporous Layered Electrode Perovskite Solar Cells
by Takaya Shioki, Naonari Izumoto, Fumitaka Iwakura, Ryuki Tsuji and Seigo Ito
Processes 2025, 13(7), 2264; https://doi.org/10.3390/pr13072264 - 16 Jul 2025
Viewed by 356
Abstract
Fully printable carbon-based multiporous layered electrode perovskite solar cells (MPLE−PSCs) are close to being commercialized due to their excellent stability, their ability to easily be scaled up, and their amenability to mass production via non-vacuum fabrication processes. To improve their efficiency, it is [...] Read more.
Fully printable carbon-based multiporous layered electrode perovskite solar cells (MPLE−PSCs) are close to being commercialized due to their excellent stability, their ability to easily be scaled up, and their amenability to mass production via non-vacuum fabrication processes. To improve their efficiency, it is important that detailed studies of the morphologies of mesoporous electrodes be carried out. In this study, we prepared five types of ZrO2 spacer layers for MPLE−PSCs, and the morphology of ZrO2 and device performance were evaluated using a scanning electron microscope, nitrogen adsorption/desorption measurements, electrode resistance measurements, UV-visible light reflectance measurements, and current density–voltage measurements. The results reveal that the adequate specific surface area and pore size distribution of mesoporous ZrO2 provided high insulation ability when used as spacers between electrodes and light absorbance, resulting in a 10.92% photoelectric conversion efficiency with a 23.22 mA cm−2 short-circuit current density. This information can serve as a guideline for designing morphologies useful for producing high-efficiency devices. Full article
(This article belongs to the Special Issue Sustainability of Perovskite Solar Cells)
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14 pages, 1927 KiB  
Article
Complete Characterization of Degradation Byproducts of Bemotrizinol and Degradation Pathway Associated with Sodium Hypochlorite Treatment
by Armando Zarrelli
Molecules 2025, 30(14), 2935; https://doi.org/10.3390/molecules30142935 - 11 Jul 2025
Viewed by 274
Abstract
The aim of this study was to elucidate all the degradation byproducts (DBPs) of bemotrizinol (BEMT) that are associated with sodium hypochlorite treatment. BEMT is a UV filter that is found not only in many personal care products, such as sunscreen and cosmetics, [...] Read more.
The aim of this study was to elucidate all the degradation byproducts (DBPs) of bemotrizinol (BEMT) that are associated with sodium hypochlorite treatment. BEMT is a UV filter that is found not only in many personal care products, such as sunscreen and cosmetics, but also as an additive in plastics or clothing to protect them from damage that results from absorbed radiation. BEMT has been detected in wastewater, surface water, and some lake sediments, in quantities from a few ng/L to hundreds of ng/L, to such an extent that, today, it is considered an emerging pollutant. In this study, the UV filter was subjected to oxidation with sodium hypochlorite, which is an oxidant at the base of the disinfection process that is used in most wastewater treatment plants or in swimming pools. Using different chromatographic methods (CC, TLC, HPLC, and GC), the resulting DBP mixture was separated into its main components, which were then identified using one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. Nineteen DBPs were isolated, and a plausible reaction mechanism was proposed to explain how they were obtained. Full article
(This article belongs to the Special Issue Degradation of Aromatic Compounds in the Environment)
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15 pages, 2330 KiB  
Review
Fungal Melanin in Plant Pathogens: Complex Biosynthesis Pathways and Diverse Biological Functions
by Hui Jia, Ning Liu, Lu Zhang, Pan Li, Yanan Meng, Wei Yuan, Haixiao Li, Dezeng Tantai, Qing Qu, Zhiyan Cao and Jingao Dong
Plants 2025, 14(14), 2121; https://doi.org/10.3390/plants14142121 - 9 Jul 2025
Viewed by 482
Abstract
Fungal melanin plays a vital role in the survival, reproduction, infection, and environmental adaptation of plant pathogenic fungi. To develop innovative strategies for managing plant fungal diseases, comprehensive investigations into melanin are imperative. Such research is fundamental to elucidating the mechanistic basis of [...] Read more.
Fungal melanin plays a vital role in the survival, reproduction, infection, and environmental adaptation of plant pathogenic fungi. To develop innovative strategies for managing plant fungal diseases, comprehensive investigations into melanin are imperative. Such research is fundamental to elucidating the mechanistic basis of fungal pathogenesis and holds promise for the design of targeted interventions against melanin-mediated virulence determinants. This review systematically elaborates on the classification of fungal melanin in plant pathogens, provides a detailed analysis of the biosynthetic processes of 3,4-dihydroxyphenylalanine (DOPA) and 1,8-dihydroxynaphthalene melanin (DHN melanins), and reveals the catalytic functions and regulatory mechanisms of key enzymes within these pathways. Melanin modulates fungal virulence by influencing appressorial integrity and turgor pressure formation, thereby participating in the host infection process and the formation of overwintering sclerotia. Melanin provides stress resistance by protecting against extreme environmental factors, including UV radiation and high temperatures. It also has the capacity to absorb heavy metals, which increases pathogen survival under adverse conditions. Furthermore, the review also explores the mechanisms of action of melanin inhibitors that target plant pathogenic fungi, providing a theoretical foundation for developing efficient and environmentally friendly antifungal medications. The complex biosynthesis pathways and diverse biological functions of fungal melanin highlight its significant theoretical and practical importance for elucidating pathogenic mechanisms and formulating scientific control strategies. Full article
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19 pages, 3941 KiB  
Article
Efficient Energy Transfer Down-Shifting Material for Dye-Sensitized Solar Cells
by Emeka Harrison Onah, N. L. Lethole and P. Mukumba
Materials 2025, 18(14), 3213; https://doi.org/10.3390/ma18143213 - 8 Jul 2025
Viewed by 275
Abstract
Dye-sensitized solar cells (DSSCs) are promising alternatives for power generation due to their environmental friendliness, cost effectiveness, and strong performance under diffused light. Conversely, their low spectral response in the ultraviolet (UV) region significantly obliterates their overall performance. The so-called luminescent down-shifting (LDS) [...] Read more.
Dye-sensitized solar cells (DSSCs) are promising alternatives for power generation due to their environmental friendliness, cost effectiveness, and strong performance under diffused light. Conversely, their low spectral response in the ultraviolet (UV) region significantly obliterates their overall performance. The so-called luminescent down-shifting (LDS) presents a practical solution by converting high-energy UV photons into visible light that can be efficiently absorbed by sensitizer dyes. Herein, a conventional solid-state technique was applied for the synthesis of an LDS, europium (II)-doped barium orthosilicate (BaSiO3:Eu2+) material. The material exhibited strong UV absorption, with prominent peaks near 400 nm and within the 200–300 nm range, despite a weaker response in the visible region. The estimated optical bandgap was 3.47 eV, making it well-suited for UV absorbers. Analysis of the energy transfer mechanism from the LDS material to the N719 dye sensitizer depicted a strong spectral overlap of 2×1010M1cm1nm4, suggesting efficient energy transfer from the donor to the acceptor. The estimated Förster distance was approximately 6.83 nm, which matches the absorption profile of the dye-sensitizer. Our findings demonstrate the potential of BaSiO3:Eu2+ as an effective LDS material for enhancing UV light absorption and improving DSSC performance through increased spectral utilization and reduced UV-induced degradation. Full article
(This article belongs to the Special Issue Advanced Luminescent Materials and Applications)
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25 pages, 5828 KiB  
Article
Study on Performance and Aging Mechanism of Rubber-Modified Asphalt Under Variable-Intensity UV Aging
by Qian Liu, Fujin Hou, Dongdong Ge, Songtao Lv and Zihao Ju
Materials 2025, 18(13), 3186; https://doi.org/10.3390/ma18133186 - 5 Jul 2025
Viewed by 458
Abstract
Prolonged ultraviolet (UV) exposure accelerates aging and degradation, while conventional constant-intensity UV simulations do not reflect the variable nature of outdoor radiation. Aging duration and film thickness are both key factors affecting Rubber-Modified Asphalt (RMA), but how their combination influences RMA remains unclear. [...] Read more.
Prolonged ultraviolet (UV) exposure accelerates aging and degradation, while conventional constant-intensity UV simulations do not reflect the variable nature of outdoor radiation. Aging duration and film thickness are both key factors affecting Rubber-Modified Asphalt (RMA), but how their combination influences RMA remains unclear. To address this limitation, this research employed accelerated aging experiments under variable-intensity UV radiation to investigate the performance and aging mechanism of RMA across different aging durations and asphalt film thicknesses. Rheological properties were analyzed through rheological tests, and the UV aging mechanisms of RMA were revealed using FTIR and SEM. The results revealed that crumb rubber improved RMA’s UV aging resistance, including high-temperature performance, fatigue life, and low-temperature cracking resistance. Aging effects were more influenced in RMA with thinner films under prolonged UV exposure. After nine cycles of ultraviolet aging, the rutting resistance, elastic recovery, fatigue life, and low-temperature cracking resistance of RMA with a 1 mm film thickness were 1.33, 1.11, 0.54, and 0.67 times, respectively, those of RMA with a 2 mm film thickness subjected to three UV aging cycles. RMA demonstrated comparable high-temperature performance and elastic recovery under UV aging conditions corresponding to a 1.5 mm film thickness aged for three cycles and a 2.0 mm film thickness aged for six cycles, as well as a 1.0 mm film thickness aged for six cycles and a 1.5 mm film thickness aged for nine cycles. FTIR showed that the increased activity of C=C and C-H under photo-oxidative aging caused a greater impact on the carbonyl groups than the sulfoxide groups. Under high-intensity UV radiation, RMA with thinner films exhibited greater rubber powder detachment, increased surface oxidation, and a substantial widening of cracks. The rubber powder absorbed UV radiation, enhancing the stability of RMA. The maximum crack width of the 1 mm NA was twice that of RMA. These provided insight into the microstructural pattern of cracking resistance degradation caused by aging. This research provides theoretical support for the optimization of the anti-aging performance of RMA. Full article
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16 pages, 1933 KiB  
Article
Investigation of the Effects of 2.45 GHz Near-Field EMF on Yeast
by Boyana Angelova, Momchil Paunov, Meglena Kitanova, Gabriela Atanasova and Nikolay Atanasov
Antioxidants 2025, 14(7), 820; https://doi.org/10.3390/antiox14070820 - 3 Jul 2025
Viewed by 441
Abstract
The study of the effects of 2.45 GHz electromagnetic fields on the health and safety of people and organisms as a whole is essential due to their widespread use in everyday life. It is known that they can cause thermal and non-thermal effects—at [...] Read more.
The study of the effects of 2.45 GHz electromagnetic fields on the health and safety of people and organisms as a whole is essential due to their widespread use in everyday life. It is known that they can cause thermal and non-thermal effects—at the molecular, cellular and organismal level. Yeast suspensions were treated with 2.45 GHz microwave radiation in the near-field of antenna at two distances (2 and 4 cm) and two time periods (20 and 60 min)—setups resembling the use of mobile devices. The release of UV-absorbing substances from the cells was studied as an indicator of membrane permeabilization, total intracellular antioxidant activity and reduced glutathione were determined, and a comet assay for damage to the DNA was performed. A correlation between reduced antioxidants and increased membrane permeability during EMF treatment was observed at a distance of 2 cm for 20 min, suggesting the presence of oxidative stress, while a similar effect was not observed with conventional heating. Slightly increased membrane permeability was observed after irradiation for 60 min at a distance of 4 cm, but this was not related to the antioxidant status of the cells. A trend towards increased DNA damage was observed under both conditions. Full article
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31 pages, 5332 KiB  
Review
Photothermal Release by Melanin-like Nanoparticles: Biomedical Applications
by Arianna Menichetti, Silvia Vicenzi, Agata Pane, Dario Mordini, Fabrizio Mancin and Marco Montalti
J. Funct. Biomater. 2025, 16(7), 243; https://doi.org/10.3390/jfb16070243 - 2 Jul 2025
Viewed by 769
Abstract
Melanin-like nanoparticles (NPs) exhibit a remarkable ability to absorb light across a wide range of wavelengths, from the ultraviolet (UV) to the near-infrared (NIR) spectrum. This characteristic enables them to serve as effective photothermal agents (PTAs). Upon irradiation, especially within the NIR window, [...] Read more.
Melanin-like nanoparticles (NPs) exhibit a remarkable ability to absorb light across a wide range of wavelengths, from the ultraviolet (UV) to the near-infrared (NIR) spectrum. This characteristic enables them to serve as effective photothermal agents (PTAs). Upon irradiation, especially within the NIR window, a region where biological tissues are highly transparent, these NPs efficiently convert light energy into heat. This phenomenon, known as the photothermal effect, leads to localized temperature increases. The resulting heat can be strategically employed to induce selective cell death in photothermal therapy (PTT) or to enhance the release of therapeutic agents directly from the NPs. The inherent versatility of melanin-like NPs, stemming from their synthesis methods and the presence of various functional groups, allows for straightforward loading with drugs or other bioactive molecules. Consequently, they are attractive tools for photothermally activated release. This review paper thoroughly examines and critically discusses the latest applications of melanin-like NPs in photothermally controlled release. We dedicate a specific section to general mechanisms and approaches, and this paper concludes with an analysis of critical challenges and prospective future developments. Full article
(This article belongs to the Special Issue Nanomaterials for Drug Targeting and Drug Delivery (2nd Edition))
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9 pages, 1553 KiB  
Communication
Orthogonally Polarized Pr:LLF Red Laser at 698 nm with Tunable Power Ratio
by Haotian Huang, Menghan Jia, Yuzhao Li, Jing Xia, Nguyentuan Anh and Yanfei Lü
Photonics 2025, 12(7), 666; https://doi.org/10.3390/photonics12070666 - 1 Jul 2025
Viewed by 171
Abstract
A continuous-wave (CW) orthogonally polarized single-wavelength red laser (OPSRL) at 698 nm with a tunable power ratio within a wide range between the two polarized components was demonstrated using two Pr3+:LiLuF4 (Pr:LLF) crystals for the first time. Through control of [...] Read more.
A continuous-wave (CW) orthogonally polarized single-wavelength red laser (OPSRL) at 698 nm with a tunable power ratio within a wide range between the two polarized components was demonstrated using two Pr3+:LiLuF4 (Pr:LLF) crystals for the first time. Through control of the waist location of the pump beam in the active media, the output power ratio of the two polarized components of the OPSRL could be adjusted. Under pumping by a 20 W, 444 nm InGaN laser diode (LD), a maximum total output power of 4.12 W was achieved with equal powers for both polarized components, corresponding to an optical conversion efficiency of 23.8% relative to the absorbed pump power. Moreover, by a type-II critical phase-matched (CPM) BBO crystal, a CW ultraviolet (UV) second-harmonic generation (SHG) at 349 nm was also obtained with a maximum output power of 723 mW. OPSRLs can penetrate deep tissues and demonstrate polarization-controlled interactions, and are used in bio-sensing and industrial cutting with minimal thermal distortion, etc. The dual-polarized capability of OPSRLs also supports multi-channel imaging and high-speed interferometry. Full article
(This article belongs to the Section Lasers, Light Sources and Sensors)
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26 pages, 6855 KiB  
Article
Hydrogel Microarray for Bioanalytical Applications: Preliminary Study on Material Properties
by Weronika Kieres, Sonia Kudłacik-Kramarczyk, Joanna Marczyk, Celina Ziejewska, Anna Drabczyk, Robert P. Socha and Marcel Krzan
Materials 2025, 18(13), 3118; https://doi.org/10.3390/ma18133118 - 1 Jul 2025
Viewed by 408
Abstract
The aim of this study was to develop and characterize UV-crosslinked hydrogel matrices based on polyethylene glycol diacrylate (PEGDA), gum arabic, betaine, and sodium alginate for potential bioanalytical applications. Various physicochemical analyses were performed, including pre-polymerization emulsion stability (Multiscan), FT-IR spectroscopy, swelling behavior [...] Read more.
The aim of this study was to develop and characterize UV-crosslinked hydrogel matrices based on polyethylene glycol diacrylate (PEGDA), gum arabic, betaine, and sodium alginate for potential bioanalytical applications. Various physicochemical analyses were performed, including pre-polymerization emulsion stability (Multiscan), FT-IR spectroscopy, swelling behavior in physiological buffers, pH monitoring, contact angle measurements, and morphological assessment via SEM and optical microscopy. The results demonstrated that both alginate content and UV exposure time significantly influence the structural and functional properties of the hydrogels. The highest swelling ratio (2.32 g/g) was observed for the formulation containing 5% sodium alginate polymerized for 5 min (5SA_5), though this sample showed mechanical fragmentation during incubation. In contrast, the most balanced performance was achieved for the 10SA_15 formulation, which maintained structural integrity and exhibited a swelling ratio of 1.92 g/g after 9 days. The contact angle analysis revealed a surface hydrophilicity range from 50° to 100°, with the lowest angle (50°) recorded for 10SA_5, indicating high surface wettability. These findings confirm the suitability of such hydrogels for biomedical applications, particularly as absorbent, stable platforms for drug delivery or wound healing. Full article
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12 pages, 1652 KiB  
Article
Catalytic Degradation of Methylene Blue Using Cellulose Acetate Composite Membrane Fabricated with Nickel Nanoparticles
by Saud Bawazeer
Catalysts 2025, 15(7), 642; https://doi.org/10.3390/catal15070642 - 30 Jun 2025
Viewed by 356
Abstract
Environmental contamination from industrial dyes, particularly Methylene Blue (MB), presents a growing challenge due to their toxicity and persistence in aquatic systems. This study explored the catalytic potential of cellulose acetate-stabilized nickel (CA/Ni) nanoparticles for the degradation of MB in aqueous solutions. CA/Ni [...] Read more.
Environmental contamination from industrial dyes, particularly Methylene Blue (MB), presents a growing challenge due to their toxicity and persistence in aquatic systems. This study explored the catalytic potential of cellulose acetate-stabilized nickel (CA/Ni) nanoparticles for the degradation of MB in aqueous solutions. CA/Ni was synthesized and characterized using FTIR and SEM, confirming its successful incorporation into the cellulose acetate matrix and uniform distribution across the membrane. UV-Vis spectrophotometry was employed to monitor the catalytic degradation of MB, revealing a significant decrease in absorbance at 665 nm over 28 min, indicating 68% degradation efficiency. Kinetic analysis showed that the degradation followed pseudo-first-order kinetics, with an apparent rate constant of 0.0348 min−1 and an R2 value of 0.9851, confirming excellent catalytic performance. The effects of temperature and pH on MB degradation were investigated, with the highest efficiency observed at 35 °C and a pH of 7. A room temperature (25 °C) and acidic conditions (pH 5) reduced the degradation rate to 52%. In comparison, a higher temperature (45 °C) and an alkaline pH (pH 9) resulted in a slight decline to 55%, likely due to changes in catalyst efficiency and MB solubility. These findings highlight the potential of Ni NP-stabilized membranes for wastewater treatment applications, providing a scalable and efficient approach to dye removal. Full article
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