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Ion beam engineering of morphological, structural, optical and photocatalytic properties of Ag-TiO2-PVA nanocomposite thin film
摘要： Development of plasmonic nanocomposite coatings with tunable optical and photocatalytic properties is important for diverse technological applications. In this paper, we report modifications in the microstructural, optical and photocatalytic properties of Ag-TiO2-PVA nanocomposite thin film by 8 MeV Si3+ ion irradiation. Ag-TiO2-PVA nanocomposite thin films on silica glass were prepared by a combination of sol-gel method and spin coating. Ion irradiation induced morphological evolution of Ag-TiO2-PVA thin film was studied by atomic force microscopy and field emission scanning electron microscopy, which revealed interesting changes in the size distribution of nanostructures with increasing ion fluence. Ion irradiation of the Ag-TiO2-PVA thin film resulted in the emergence of SPR peak of Ag nanoparticles at 456 nm, which shifted to 446 nm along with enhancement in intensity as the ion fluence was increased. Significant enhancement in the photocatalytic efficiency of Ag-TiO2-PVA nanocomposite thin film for degradation of methylene blue was observed upon ion irradiation at 1 × 1013 ions/cm2. The origins of microstructural, morphological, optical and plasmonic modifications and enhancement in the photocatalytic efficiency of Ag-TiO2-PVA nanocomposite thin films have been discussed.
关键词： Ion irradiation,Surface plasmon resonance,Nanocomposite,Photocatalysis,Ag-TiO2-PVA
更新于2025-09-23 15:22:29
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Liquid Phase Studies of Nanomaterials
摘要： Liquid cell transmission electron microscopy (LCTEM) is a relatively new technique enabling researchers to study dynamic phenomena in materials sciences, life sciences and electrochemistry. LCTEM has proved to be a remarkable tool for observing colloidal nanoparticle syntheses at fairly high temporal and spatial resolutions offered by transmission electron microscopy (TEM). Though the idea of observing syntheses in their native media is not new, a practical approach has only been made possible through massive improvements in microfabrication technology to fabricate liquid cells.[1] The idea is to use thin window materials such as SiN membranes (50 nm or less) to encapsulate tens of cubic nanometers of liquid in a stable thin profile suitable forTEM imaging considering the vacuum environment of the microscope (Fig. 1).
关键词： Radiolysis,Nanoparticles,Electron beam irradiation,Solvent,Liquid cell TEM
更新于2025-09-23 15:21:21
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Determination of Effective Dose of Ultraviolet Irradiation to Influent Water for Prevention of <i>Kudoa yasunagai</i> Infection
摘要： We determined the minimum ultraviolet (UV) irradiation dose to influent water to prevent Kudoa yasunagai infection, using microscopy and qPCR. The infection prevalence in Seriola lalandi reared in untreated water reached 45% while that in fish reared in UV-treated water at 5 mJ/cm2 remained below 10%. Additionally, 5 mJ/cm2 UV irradiation significantly reduced spore formation in the brain. No infection was detected when the water was treated with UV at the doses 15 and 30 mJ/cm2. These results indicate that K. yasunagai actinospores are relatively vulnerable to UV irradiation and the minimum effective dose lies between 5 and 15 mJ/cm2.
关键词： quantitative PCR,ultraviolet irradiation,Seriola lalandi,prevention,Kudoa yasunagai,hatchery
更新于2025-09-23 15:21:21
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3D graphene aerogels/Sb2WO6 hybrid with enhanced photocatalytic activity under UV- and visible-light irradiation
摘要： A novel ultraviolet (UV)- and visible-light-active 3D graphene aerogels (3DGA)/Sb2WO6 hybrid photocatalyst was prepared by electrostatic self-assembly (ESSA) method. The photocatalytic activity of the 3DGA/Sb2WO6 hybrid was studied by monitoring the change in the concentration of methyl orange (MO) under UV-light and visible-light irradiation. The results demonstrated that the as-prepared hybrid exhibited significantly enhanced efficiency for the photodegradation of MO in comparison with pure Sb2WO6. This was ascribed to the efficient separation of the photogenerated electrons (e–) and holes (h+) with the aid of 3DGA as well as the generated reactive superoxide radical anions (O2(cid:129)–). Moreover, the 3DGA/Sb2WO6 hybrid exhibited high recyclability, because the highly hydrophobic 3DGA in the hybrid was very advantageous to the separation of the hybrid photocatalyst from the MO solutions.
关键词： 3D graphene aerogels,Sb2WO6,Electrostatic self-assembly,Hybrid photocatalyst,Visible-light irradiation
更新于2025-09-23 15:21:21
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Spectral features of nuclear DNA in human sperm assessed by Raman Microspectroscopy: Effects of UV-irradiation and hydration
摘要： Raman Microspectroscopy represents an innovative tool for the assessment of sperm biochemical features otherwise undetectable by routine semen analysis. Previously, it was shown that induced DNA damage can be detected in smeared sperm by this technique. This novel readout may be of value for clinical settings especially if it can be transferred to living cells. Yet, starting with living sperms this study was carried-out using a variety of conditions to disclose the Raman features of sperm nuclei under different hydration conditions and UV exposure. Human sperm were immobilized and Raman spectra were obtained from individual sperm as repeated measurements. To create conditions with controlled DNA damage, sperm samples were exposed to ultraviolet light. Several media were used to evaluate their effect on Raman spectra in aqueous conditions. To substantiate differences between the experimental conditions, the spectra were analyzed by Principal Component Analysis. We observed that spectra of sperm nuclei obtained in different solutions showed a qualitatively unchanged spectral pattern showing the principal signals related to DNA. Evaluating the effect of ultraviolet light generated the finding that spectra representing DNA damage were only observed in dry conditions but not in aqueous medium. Thus, Raman microspectroscopy was successfully applied for sperm analysis in different conditions, among them in live spermatozoa in aqueous solution during the initial measurement, revealing the principle use of this technique. However, implementation of Raman spectroscopy as a technique for clinical sperm analysis and selection may be especially relevant when DNA evaluation can be established using live sperm.
关键词： hydration,DNA damage,sperm,UV-irradiation,Raman Microspectroscopy
更新于2025-09-23 15:21:21
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An inverse approach to identify selective angular properties of retro-reflective materials for urban heat island mitigation
摘要： This work presents the preliminary stages of a wider study aiming at assessing the potentials of retro-re?ective (RR) materials to mitigate urban heat island e?ects. Th study herewith reported is based on an inverse approach, which originates from the evaluation of the solar irradiation incident on urban surfaces (i.e. fa?ade, roof, and paving) and leads to the identi?cation of the optimal angular properties required to activate such a material. The solar radiation geometry and the solar irradiation collected by the south-exposed vertical and the horizontal surfaces, were assessed by solar dynamic simulation tools. Furthermore, the angular distribution of the solar direct irradiation component and the direct to global solar irradiation ratio were estimated. The analyses were carried out for nine locations between Oulu (Finland) and Doha (Qatar), with an increment of 5° latitude between two locations. The results demonstrate that the application of RR materials to horizontal surfaces can always be e?ective, whereas when applied on the vertical surface, the solar geometry in?uences to a much greater extent the performance of these materials. The main ?ndings of this study show that the selective angular properties of an ideal RR material should be in the angular interval between 25° and 55° and between 30° and 90°, in case of vertical surfaces and horizontal surfaces, respectively. Best practices related to the application of RR materials and the activation of their selective angular properties in di?erent climate zones are also reported.
关键词： Solar irradiation,Retro-re?ective materials,Selective angular properties,Urban heat island
更新于2025-09-23 15:21:21
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Aloe-Emodin/Carbon Nanoparticles Hybrid Gels with Light-Induced and Long-Term Antibacterial Activity
摘要： Development of effective antimicrobial wound dressings has drawn wide attention in the wound care market. Here, we synthesized a natural antibiotic (aloe-emodin, AE) and carbon nanoparticles co-embedded polymer hybrid hydrogel as a novel wound dressing in the fight against skin infections potently. We systematically evaluated the properties of the obtained hydrogels, including physic-chemical characteristics, photothermal conversion efficiency, reactive oxygen species (ROS) generation, AE-released profile, antibacterial activity and wound-healing capability. The hybrid gels can initially deduct the number of bacteria rapidly in a short time through the near-infrared-light (NIR)-triggered photothermal/ROS route, and continuously kill the remaining live cells by released-AE from gels after turning off NIR source with the long-term antibacterial effect. These two antibacterial manners that complement each other lead to the excellent antibacterial performances towards various bacterial strains including multidrug-resistant bacteria. Moreover, in vivo Staphylcoccus aureus-infected animal experiments indicate that the hybrid gels upon NIR irradiation have a striking ability towards wound infection. These studies demonstrate that the AE and carbon nanoparticles co-embedded hybrid polymer hydrogels with NIR exposure may have applications in the wound combined care for bacterial infections.
关键词： NIR irradiation,aloe-emodin,wound dressing,ROS,carbon nanoparticles,antibacterial hydrogel
更新于2025-09-23 15:21:21
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Effect of photo-irradiation on metal insulator transition in vanadium dioxide
摘要： We report a large transition temperature (TC) decrease in a VO2 thin film device under photo-irradiation. With the increasing photo-irradiation intensity (PIntensity) with a wavelength of 405 nm, the TC of the VO2 device decreased at a rate of (cid:2)3:2 (cid:3) 10(cid:4)2 W=cm2 and reached as low as 40.0 (cid:5)C at a PIntensity of 8:4 (cid:3) 102 W=cm2. While the change in TC is primarily due to the photothermal effect when the PIntensity is below 3:6 (cid:3) 102 W=cm2, both the photothermal and photo-induced carrier density effects contribute to the change in TC when the PIntensity is above 6:4 (cid:3) 102 W=cm2.
关键词： metal-insulator transition,vanadium dioxide,photothermal effect,photo-induced carrier density,photo-irradiation
更新于2025-09-23 15:21:21
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Macroscopic effects and microscopic origins of gamma-ray irradiation on In-doped CdZnTe crystal
摘要： The effects of gamma-ray irradiation, exposed to a 60Co source with a dose of 2.7 kGy, on In-doped CdZnTe (CdZnTe:In) crystal were investigated. We combined the “macroscopic” electrical properties of CdZnTe:In sample, evaluated by current–voltage (I–V) measurements at different temperature, with the “microscopic” origins of electrically active defects induced by gamma-irradiation, characterized by thermally stimulated current spectroscopy. It reveals that the bulk resistivity at room temperature have increased from 2.7 × 109 ? cm for the as-grown CdZnTe:In sample to 5.9 × 109 ? cm for the irradiated sample. Since the microscopic origins of these macroscopic effects are linked to the electrically active defects within the material, five main defect states (I, II, III, IV and V) were characterized and identified in the CdZnTe:In crystal. In particular, the introduction of gamma-irradiation altered the trap concentrations of these defect states, such as the rapidly decreasing concentration of region I. Besides, the gamma-ray irradiation caused a further deepening of EDD level (region V) from the value of 0.717 ± 0.004 eV for the as-grown sample to the value of 0.749 ± 0.004 eV for the irradiated sample. The microscopic origin of EDD level was identified with TeCd2+ below the conduction band minimum, which is responsible for the pinning of EF level near the mid-gap, and thus for the observed high-resistivity performance of CdZnTe:In.
关键词： high-resistivity,electrical properties,defect states,gamma-ray irradiation,CdZnTe:In
更新于2025-09-23 15:21:21
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Light-Triggered Reversible Self-Engulfing of Janus Nanoparticles
摘要： Block copolymers containing azobenzene liquid crystalline (LC) mesogen are used to prepare snowman-like Janus nanoparticles (NPs) by emulsion solvent evaporation. The azobenzene-containing poly(methacrylate) (PMAAz) head of the Janus NPs is in the smectic LC phase with ordered stripes, which becomes amorphous and enlarged due to trans/cis transformation under UV irradiation. The expanded PMAAz can consequently engulf the other head. The self-engulfed NPs can recover to their original state in both shape and LC state via visible-light irradiation. This strategy is promising for programmable load and release of different payloads by remote trigger using light.
关键词： emulsion solvent evaporation,azobenzene,liquid crystalline,Block copolymers,Janus nanoparticles,programmable load and release,UV irradiation,visible-light irradiation
更新于2025-09-23 15:21:01