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Increased resistance of <i>Salmonella</i> Typhimurium and <i>Escherichia coli</i> O157:H7 to 222-nm krypton-chlorine excilamp treatment by acid adaptation
摘要： In this study, we examined the change in resistance of Salmonella Typhimurium and Escherichia coli O157:H7 to 222-nm krypton-chlorine (KrCl) excilamp treatment as influenced by acid adaptation, and identified a mechanism of resistance change. In addition, changes in apple juice quality indicators such as color, total phenols and DPPH free radical scavenging activity during treatment were measured. Acid adapted- and non-acid adapted pathogens were induced by growing the cells in TSB without dextrose (TSB w/o D) at pH 7.3 and TSB w/o D at pH 5.0 adjusted with HCl, respectively. For the KrCl excilamp treatment, acid-adapted pathogens exhibited significantly (P < 0.05) higher D5d values, which indicate dosages required for achieving 5-log reduction, than non-acid adapted pathogens in both commercially clarified apple juice and PBS, and the pathogens in the juice showed significantly (P < 0.05) higher D5d values than those in PBS because of the UV-absorbing characteristics of apple juice. Through mechanism identification, it was found that the generation of lipid peroxidation in cell membrane, inducing cell membrane destruction, of acid adapted cells was significantly (P < 0.05) less than that of non-acid adapted cells for the same amount of reactive oxygen species (ROS) generated at the same dose because the ratio of unsaturated to saturated fatty acids (USFA/SFA) in the cell membrane was significantly (P < 0.05) decreased as a result of acid adaptation. Treated apple juice showed no significant (P > 0.05) differences in quality indicators compared to untreated controls during the treatment of 1773 mJ/cm2.
关键词： acid adaptation,ROS,E. coli O157:H7,apple juice,cell membrane fatty acid,ultraviolet irradiation,S. Typhimurium,222-nm KrCl excilamp
更新于2025-09-23 15:22:29
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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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Removal of humic acid from <b>aqueous solutions</b> using ultraviolet irradiation coupled with hydrogen peroxide and zinc oxide nanoparticles
摘要： In this study, individual performance of ultraviolet irradiation (UV), zinc oxide nanoparticles (ZnO) and hydrogen peroxide (H2O2) processes, as well as a performance of combined processes of UV/H2O2 and UV/H2O2/ZnO, were assessed for the removal of humic acid (HA) from aqueous solutions. Various process-related factors, such as the concentration of ZnO (0.2 and 0.5 g/L), the concentration of H2O2 (20, 30 and 50 mg/L), UV = 125 W, pH (4, 7 and 10), initial HA concentrations (at wavelength of 254 nm) of 2, 5, 7 and 10 mg/L, and three types of interferences (nitrate, sulphate and chloride) were studied and optimised. The results showed that removal e?ciency decreased by increasing the concentration of HA and pH values in all processes, but it increased by increasing the time of exposure and the concentration of H2O2. In the combined process of UV/ZnO/H2O2, the nanoparticle concentration of 0.2 g/L yielded the highest e?ciency, whereas in the other processes, the highest e?ciency was observed at nanoparticle concentration of 0.5 g/L. Based on these results, under the optimum conditions (HA = 2 mg/L, H2O2 = 50 mg/L, ZnO = 0.2 g/L, pH = 4.0 and contact time of 15 min), UV/ZnO/H2O2 process was found as the most e?cient combination in removing of HA with an e?ciency of 99.99%. Furthermore, the modelling results indicated that the adsorption reaction of HA onto ZnO nanoparticles was very well described by the pseudo-second-order kinetic model (R2 > 0.99).
关键词： hydrogen peroxide,Ultraviolet irradiation,zinc oxide nanoparticles,humic acid
更新于2025-09-23 15:19:57
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Enhanced Performances of p-Si/n-ZnO Self-powered Photodetector by Interface State Modification and Pyro-phototronic Effect
摘要： ZnO based self-powered photodetector (PD) has great application potential in distributing sensor networks and internet of things. However, a large number of surface or interface states within ZnO limit its performance improvement. Here, the surface and interface states of ZnO is greatly eliminated by ultraviolet irradiation as an interfacial modification engineering. Reduction of interface states reduces ohmic resistance, also enhances the tuning role of pyro-phototronic effect. And the transient response currents of the self-powered PD are thus significantly improved with a maximal enhancement factor of more than 5900% for the 325-785 nm broadband stimulating beams. The corresponding response time is decreased to few milliseconds or sub-milliseconds. The results indicate that surface-state reduction of ZnO can effectively enhance the modifying role of pyro-phototronic effect and greatly improve the response performances of the self-powered broadband PDs with great application demands in Internet of things, broad spectral detecting and imaging, and smart optoelectronic devices.
关键词： Self-powered,ultraviolet irradiation,interface states,pyro-phototronic effect,broadband photodetectors
更新于2025-09-23 15:19:57
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An Ultravioleta??Deposited MoO <sub/>3</sub> Film as Anode Interlayer for Higha??Performance Polymer Solar Cells
摘要： An ultraviolet-deposited MoO3 film is developed as anode interlayer based on molybdenum(V) chloride as precursor. The ultraviolet-deposited MoO3 film is prepared from the precursor film (spin coated from its solution) with ultraviolet irradiation treatment, and the preparation process of the MoO3 film is facile, low cost, and compatible with mass production and flexible substrate. The composition of the MoO3 film is analyzed by X-ray photoelectron spectroscopy. The work function as well as the surface morphology and wettability of indium tin oxide (ITO) modified by the MoO3 film are investigated by ultraviolet photoelectron spectroscopy, atomic force microscopy, and contact angle tester, respectively, where the analyses show the ITO modified by the MoO3 anode interlayer can offer excellent energy level alignment and interface contact with active layer. The photovoltaic performance of nonfullerene polymer solar cells (PSCs) based on the MoO3 anode interlayer is researched with typical and relatively low-cost PBDB-T:ITIC as active layer, and the ITO/MoO3-based device shows the highest power conversion efficiency of 9.27% compared with the bare ITO-based device (3.69%) and the ITO/PEDOT:PSS-based device (9.15%). The results demonstrate the great potential of the ultraviolet-deposited MoO3 film as anode interlayer for high-performance PSCs.
关键词： ultraviolet irradiation,photovoltaic performance,MoO3 film,polymer solar cells,anode interlayer
更新于2025-09-19 17:13:59
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AIP Conference Proceedings [Author(s) 4TH ELECTRONIC AND GREEN MATERIALS INTERNATIONAL CONFERENCE 2018 (EGM 2018) - Bandung, Indonesia (27–28 July 2018)] - Effects of Ag dopant and ultraviolet irradiation on structural properties of zinc oxide nanostructures
摘要： ZnO nanorods are promising UV light driven photocatalyst for the degradation of organic dyes. In this work, the effects of Ag dopant (0.02 to 0.1 mol%) and ultraviolet irradiation (0 to 6 min) on structural, optical and photocatalytic properties of zinc oxide nanorods were investigate. The Ag incorporation ZnO nanoraod have been grown on glass substrate by chemical solution deposition method. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–vis absorption spectroscopy (UV–vis). The XRD spectra of the Ag incorporation ZnO (Ag-ZnO) films indicate that Ag was incorporated in the wurtzite hexagonal crystal structure of ZnO and the crystallinity were enhanced with increasing of Ag amount as well as ultraviolet irradiation time. SEM micrographs of pure ZnO films revealed the uniform distribution of rod-like nanostructure of size of about 30-40 nm. Increasing Ag amount as well as irradiation time stimulated the optical properties of ZnO nanostructures. The photocatalytic activity of these nanostructures was evaluated by analysing UV irradiation degradation of methyl orange (MO) dye and it was observed that Ag-ZnO show significantly enhanced photocatalytic activity for degradation of MO, as compared to ZnO nanorods.
关键词： structural properties,ZnO nanorods,ultraviolet irradiation,Ag dopant,photocatalytic activity
更新于2025-09-04 15:30:14
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Voltammetric Determination of Bisphenol A Based on Its Anodic Deposition at Chitosan-Graphene Modified Glassy Carbon Electrode under UV Irradiation
摘要： Bisphenol A (BPA) was successfully electrodeposited on glassy carbon electrode modified with the chitosan-graphene (Chit-GR/GCE) by multiple sweep voltammetry under ultraviolet (UV) irradiation. The experimental conditions of the BPA deposits and the probable oxidation mechanism were investigated. Two oxidation peaks (peakⅡ=0.12 V, peakⅢ=0.20 V) appeared in a suitable potential range of 0.0V and 0.2V at the Chit-GR/GC eletrode in the presence of UV light, and it could be seen that the oxidation peak current increased with the increase of UV irradiation time. The emerging peakⅢ was reported firstly in the work, which showed that the Chit-GR modified electrode had catalytic activity on the oxidation of BPA. Based on the oxidation peak (peakⅢ) of BPA oxidative porducts on the Chit-GR/GC electrode under UV irradiation, the electrochemical sensor was fabiracated for determination of BPA. The calibration curve was obtained in the range of 5.0 to 200.0 μM with the limit of detection of 0.34 μM (S/N=3) and the response sensitivity of 0.33 μA μM-1, which was higher than those of the method of determining BPA based on the direct oxidtation of BPA (0.98 μM (S/N=3), 0.12 μA μM-1). It was applied successfully for determination of BPA in lake, soil and plastic bottle samples. The new strategy, based on anodic electrodeposition and photocatalytic oxidation of BPA oxidation porducts, was provided for determination of BPA under UV irradiation. It was green, evironmental and effective.
关键词： Ultraviolet irradiation,Bisphenol A,Graphene,Anodic deposition
更新于2025-09-04 15:30:14