Displaying publications 1 - 20 of 140 in total

  1. Suhaimi SMI, Muhamad NA, Bashir N, Mohd Jamil MK, Abdul Rahman MN
    Sensors (Basel), 2022 Jan 18;22(3).
    PMID: 35161466 DOI: 10.3390/s22030722
    Flashover on transmission line insulators is one of the major causes of line outages due to contamination from the environment or ageing. Power utility companies practicing predictive maintenance are currently exploring novel non-contact methods to monitor insulator surface discharge activities to prevent flashover. This paper presents an investigation on the UV pulse signals detected using UV pulse sensor due to the discharges on the insulator surfaces under varying contamination levels and insulator ages. Unaged and naturally aged insulators (0 to >20 years) were artificially contaminated (none, light to heavy contamination). The electrical stresses on the insulator surfaces were varied to generate varying discharge intensity levels on the surfaces of the insulator. The DC and harmonic components of UV pulse signals detected during surface discharges were recorded and analysed. Results show a positive correlation between the discharge intensity level of contaminated and aged transmission insulators with the DC and harmonic components of the UV pulse signals. Furthermore, the study revealed that under dry insulator surface conditions, insulator ageing has a more profound effect during discharges than contamination level. The findings from this study suggest that the use of UV pulse sensors to monitor UV pulse signals emitted during insulator surface discharges can be another novel non-contact method of monitoring transmission line insulator surface conditions.
    Matched MeSH terms: Ultraviolet Rays*
  2. Ng KH, Khan MR, Ng YH, Hossain SS, Cheng CK
    J Environ Manage, 2017 Jul 01;196:674-680.
    PMID: 28365553 DOI: 10.1016/j.jenvman.2017.03.078
    In this study, we have employed a photocatalytic method to restore the liquid effluent from a palm oil mill in Malaysia. Specifically, the performance of both TiO2 and ZnO was compared for the photocatalytic polishing of palm oil mill effluent (POME). The ZnO photocatalyst has irregular shape, bigger in particle size but smaller BET specific surface area (9.71 m2/g) compared to the spherical TiO2 photocatalysts (11.34 m2/g). Both scavenging study and post-reaction FTIR analysis suggest that the degradation of organic pollutant in the TiO2 system has occurred in the bulk solution. In contrast, it is necessary for organic pollutant to adsorb onto the surface of ZnO photocatalyst, before the degradation took place. In addition, the reactivity of both photocatalysts differed in terms of mechanisms, photocatalyst loading and also the density of photocatalysts. From the stability test, TiO2 was found to offer higher stability, as no significant deterioration in activity was observed after three consecutive cycles. On the other hand, ZnO lost around 30% of its activity after the 1st-cycle of photoreaction. The pH studies showed that acidic environment did not improve the photocatalytic degradation of the POME, whilst in the basic environment, the reaction media became cloudy. In addition, longevity study also showed that the TiO2 was a better photocatalyst compared to the ZnO (74.12%), with more than 80.0% organic removal after 22 h of UV irradiation.
    Matched MeSH terms: Ultraviolet Rays*
  3. Amjad M, Mohyuddin A, Ulfat W, Goh HH, Dzarfan Othman MH, Kurniawan TA
    J Environ Manage, 2024 Feb 27;353:120287.
    PMID: 38335595 DOI: 10.1016/j.jenvman.2024.120287
    Textile wastewater laden with dyes has emerged as a source of water pollution. This possesses a challenge in its effective treatment using a single functional material. In respond to this technological constraint, this work presents multifunctional cotton fabrics (CFs) within a single, streamlined preparation process. This approach utilizes the adherence of Ag NPs (nanoparticles) using Si binder on the surface of CFs, resulting in Ag-coated CFs through a pad dry method. The prepared samples were characterized using scanning electron microscope-energy dispersive X-ray electroscopy (SEM-EDS), thermal gravimetric analysis (TGA), Fourier transformation infrared (FT-IR). It was found that the FT-IR spectra of Ag NPs-coated CFs had peaks appear at 3400, 2900, and 1200 cm-1, implying the stretching vibrations of O-H, C-H, and C-O, respectively. Based on the EDX analysis, the presence of C, O, and Ag related to the coated CFs were detected. After coating the CFs with varying concentrations of Ag NPs (1%, 2% and 3% (w/w)), they were used to remove dyes. Under the same concentration of 10 mg/L and optimized pH 7.5 and 2 h of reaction time, 3% (w/w) Ag-coated CFs exhibited a substantial MB degradation of 98 %, while removing 95% of methyl orange, 85% of rhodamine B, and 96% of Congo red, respectively, following 2 h of Vis exposure. Ag NPs had a strong absorption at 420 nm with 2.51 eV of energy band gap. Under UV irradiation, electrons excited and produced free radicals that promoted dyes photodegradation. The oxidation by-products included p-dihydroxybenzene and succinic acid. Spent Ag-coated CFs attained 98% of regeneration efficiency. The utilization of Ag-coated CFs as a photocatalyst facilitated treated effluents to meet the required discharge standard of lower than 1 mg/L mandated by national legislation. The integration of multifunctional CFs in the treatment system presents a new option for tackling water pollution due to dyes.
    Matched MeSH terms: Ultraviolet Rays*
  4. Alvankarian J, Majlis BY
    PLoS One, 2015;10(3):e0119658.
    PMID: 25747514 DOI: 10.1371/journal.pone.0119658
    Rapid prototyping (RP) of microfluidic channels in liquid photopolymers using standard lithography (SL) involves multiple deposition steps and curing by ultraviolet (UV) light for the construction of a microstructure layer. In this work, the conflicting effect of oxygen diffusion and UV curing of liquid polyurethane methacrylate (PUMA) is investigated in microfabrication and utilized to reduce the deposition steps and to obtain a monolithic product. The conventional fabrication process is altered to control for the best use of the oxygen presence in polymerization. A novel and modified lithography technique is introduced in which a single step of PUMA coating and two steps of UV exposure are used to create a microchannel. The first exposure is maskless and incorporates oxygen diffusion into PUMA for inhibition of the polymerization of a thin layer from the top surface while the UV rays penetrate the photopolymer. The second exposure is for transferring the patterns of the microfluidic channels from the contact photomask onto the uncured material. The UV curing of PUMA as the main substrate in the presence of oxygen is characterized analytically and experimentally. A few typical elastomeric microstructures are manufactured. It is demonstrated that the obtained heights of the fabricated structures in PUMA are associated with the oxygen concentration and the UV dose. The proposed technique is promising for the RP of molds and microfluidic channels in terms of shorter processing time, fewer fabrication steps and creation of microstructure layers with higher integrity.
    Matched MeSH terms: Ultraviolet Rays*
  5. Saw KG, Tneh SS, Yam FK, Ng SS, Hassan Z
    PLoS One, 2014;9(2):e89348.
    PMID: 24586707 DOI: 10.1371/journal.pone.0089348
    The concentration of acceptor carriers, depletion width, magnitude of donor level movement as well as the sensitivity factor are determined from the UV response of a heterojunction consisting of ZnO on type IIb diamond. From the comparison of the I-V measurements in dark condition and under UV illumination we show that the acceptor concentration (∼10(17) cm(-3)) can be estimated from p-n junction properties. The depletion width of the heterojunction is calculated and is shown to extend farther into the ZnO region in dark condition. Under UV illumination, the depletion width shrinks but penetrates both materials equally. The ultraviolet illumination causes the donor level to move closer to the conduction band by about 50 meV suggesting that band bending is reduced to allow more electrons to flow from the intrinsically n-type ZnO. The sensitivity factor of the device calculated from the change of threshold voltages, the ratio of dark and photocurrents and identity factor is consistent with experimental data.
    Matched MeSH terms: Ultraviolet Rays*
  6. Mengting Z, Kurniawan TA, Yanping Y, Avtar R, Othman MHD
    Mater Sci Eng C Mater Biol Appl, 2020 Mar;108:110420.
    PMID: 31924000 DOI: 10.1016/j.msec.2019.110420
    Bisphenol A (BPA) is a refractory pollutant presents in water body that possesses serious threats to living organisms. To deal with it, we investigate and evaluate the effectiveness of GO@BiOI/Bi2WO6 composite as a novel photocatalyst for BPA removal from aqueous solutions under UV-vis irradiation. To enhance its removal for BPA, the surface of BiOI/Bi2WO6 is modified with graphene oxide (GO). This composite is named as 'GO@BiOI/Bi2WO6'. Changes in its physico-chemical properties after surface modification with GO are characterized by XRD, FTIR, FESEM-EDS, XPS, PL, and BET methods. Optimized conditions of BPA degradation by the composite are determined under identical conditions. Photodegradation pathways of BPA and its removal mechanisms by the same composite are presented. It is obvious that the GO@BiOI/Bi2WO6 has demonstrated its potential as a promising photocatalyst for BPA removal under UV-vis irradiation. About 81% of BPA removal is attained by the GO@BiOI/Bi2WO6 under optimized conditions (10 mg/L of BPA, 0.5 g/L of dose, pH 7 and 5 h of reaction time). The oxidation by-products of BPA degradation include p-hydroquinone or 4-(1-hydroxy-1-methyl-ethyl)-phenol. In spite of its performance, the treated effluents are still unable to meet the maximum discharge limit of <1 mg/L set by national legislation. Therefore, subsequent biological processes are essential to maximize its biodegradation in the wastewater samples before their discharge into waterbody.
    Matched MeSH terms: Ultraviolet Rays*
  7. Ng SY, Eh Suk VR, Gew LT
    J Cosmet Dermatol, 2022 Nov;21(11):5409-5444.
    PMID: 35723888 DOI: 10.1111/jocd.15170
    BACKGROUND: Excessive exposure to ultraviolet radiation has harmful effects on human skin. At present, synthetic and mineral types of sunscreens used to protect against these harmful damages have been reported to cause negative health and environmental effects. The studies involving characterization and isolation of phytoconstituents from natural botanical sources are important to discover their potential beneficial effects on sunscreen development AIM: This systematic review provides specific and compiled information on the photoprotective properties of natural botanical sources for sunscreen development. The efforts in research and innovation are essential to ensure the safety and sustainability of plant-based sunscreen products.

    METHODS: In this review, a total of 35 articles were selected using the Scopus database based on the inclusion and exclusion criteria RESULT: The significant correlation between total phenolic content, total flavonoid content, antioxidant activities, and sun protection factor were shown in these studies which confirmed the potential benefits of natural plants in sunscreen development.

    CONCLUSIONS: In addition, natural botanical sources also exhibit excellent anti-tyrosinase, anti-aging, and anti-inflammatory activities. However, the biological activities of plants were dependent on the solvents used for extraction.

    Matched MeSH terms: Ultraviolet Rays/adverse effects
  8. Thor SH, Ho LN, Ong SA, Abidin CZA, Heah CY, Yap KL
    Environ Sci Pollut Res Int, 2023 Mar;30(12):34363-34377.
    PMID: 36512276 DOI: 10.1007/s11356-022-24647-5
    Photocatalytic fuel cell (PFC) was employed to provide renewable power sources to photoelectro-Fenton (PEF) process to fabricate a double-chambered hybrid system for the treatment of azo dye, Amaranth. The PFC-PEF hybrid system was interconnected by a circuit attached to the electrodes in PFC and PEF. Circuit connection is the principal channel for the electron transfer and mobility between PFC and PEF. Thus, different circuit connections were evaluated in the hybrid system for their influences on the Amaranth dye degradation. The PFC-PEF system under the complete circuit connection condition attained the highest decolourization efficiency of Amaranth (PFC: 98.85%; PEF: 95.69%), which indicated that the complete circuit connection was crucial for in-situ formation of reactive species in dye degradation. Besides, the pivotal role of ultraviolet (UV) light irradiation in the PFC-PEF system for both dye degradation and electricity generation was revealed through various UV light-illuminating conditions applied for PFC and PEF. A remarkable influence of UV light irradiation on the production of hydrogen peroxide and generation and regeneration of Fe2+ in PEF was demonstrated. This study provided a comprehensive mechanistic insight into the dye degradation and electricity generation by the PFC-PEF system.
    Matched MeSH terms: Ultraviolet Rays*
  9. George DS, Razali Z, Santhirasegaram V, Somasundram C
    J Sci Food Agric, 2016 Jun;96(8):2851-60.
    PMID: 26350493 DOI: 10.1002/jsfa.7454
    Postharvest treatments of fruits using techniques such as ultraviolet-C have been linked with maintenance of the fruit quality as well as shelf-life extension. However, the effects of this treatment on the quality of fruits on a proteomic level remain unclear. This study was conducted in order to understand the response of mango fruit to postharvest UV-C irradiation.
    Matched MeSH terms: Ultraviolet Rays
  10. Abdul Halim Abdullah, Wong WY, Mohd Ismail Yaziz
    The decolorization of reactive orange 16 dye (RO16) from aqueous solution by CuO/H2O2 was investigated. The amount of dye removed was determined by measuring the concentration of the dye at its characteristic wavelengths by UV-Vis spectrophotometer. The effects of CuO dose, H2O2 concentration and UV light on the decolorization of the dye were investigated. It was found that the removal rate increased with increasing mass of CuO and increasing concentration of H2O2. The combination of CuO, H2O2 and UV light was the best system with dye removal of 100% after 6 h. The removal efficiency observed was in the order: CuO/UV/H2O2 > CuO/H2O2 > CuO/UV = CuO > UV/H2O2 > H2O2 > UV.
    Matched MeSH terms: Ultraviolet Rays
  11. Li B, Amin AH, Ali AM, Isam M, Lagum AA, Sabugaa MM, et al.
    Chemosphere, 2023 Sep;336:139208.
    PMID: 37321458 DOI: 10.1016/j.chemosphere.2023.139208
    UV and solar-based photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP) as an organic contaminant in ceramics industry wastewater by ZnS and Fe-doped ZnS NPs was the focus of this research. Nanoparticles were prepared using a chemical precipitation process. The cubic, closed-packed structure of undoped ZnS and Fe-doped ZnS NPs was formed in spherical clusters, according to XRD and SEM investigations. According to optical studies, the optical band gaps of pure ZnS and Fe-doped ZnS nanoparticles are 3.35 and 2.51 eV, respectively, and Fe doping increased the number of carriers with high mobility, improved carrier separation and injection efficiency, and increased photocatalytic activity under UV or visible light. Doping of Fe increased the separation of photogenerated electrons and holes and facilitated charge transfer, according to electrochemical impedance spectroscopy investigations. Photocatalytic degradation studies revealed that in the present pure ZnS and Fe-doped ZnS nanoparticles, 100% treatment of 120 mL of 15 mg/L phenolic compound was obtained after 55- and 45-min UV-irradiation, respectively, and complete treatment was attained after 45 and 35-min solar light irradiation, respectively. Because of the synergistic effects of effective surface area, more effective photo-generated electron and hole separation efficiency, and enhanced electron transfer, Fe-doped ZnS demonstrated high photocatalytic degradation performance. The study of Fe-doped ZnS's practical photocatalytic treatment capability for removing 120 mL of 10 mg/L 2,4-DCP solution made from genuine ceramic industrial wastewater revealed Fe-doped ZnS's excellent photocatalytic destruction of 2,4-DCP from real industrial wastewater.
    Matched MeSH terms: Ultraviolet Rays
  12. Valappil NKM, Mammen PC, de Oliveira-Júnior JF, Cardoso KRA, Hamza V
    Environ Monit Assess, 2024 Jan 03;196(2):106.
    PMID: 38168710 DOI: 10.1007/s10661-023-12239-w
    The spatial and temporal dynamics of daily ultraviolet index (UVI) for a period of 18 years (2004-2022) over the Indian state of Kerala were statistically characterised in the study. The UVI measurements used for the study were derived from the ultraviolet-B (UVB) irradiance measured by the Ozone Monitoring Instrument (OMI) of the AURA satellite and classified into different severity levels for analysis. Basic statistics of daily, monthly and seasonal UVI as well as Mann-Kendall (MK) statistical trend characteristics and the rate of change of daily UVI using Theil-Sen's slope test were also evaluated. A higher variability of UVI characteristics was observed in the Kerala region, and more than 79% of the measurements fell into the categories of very high and extreme UVI values, which suggests the need of implementation of appropriate measures to reduce health risks. Although the UVI measured during the study period shows a slight decrease, most of the data show a seasonal variation with undulating low and peak values. Higher UVI are observed during the months of March, April and September. The region also has higher UVI during the southwest monsoon (SWM) and summer seasons. Although Kerala region as a single whole unit, UVI show a non-significant decreasing trend (-0.83), the MK test revealed the increasing and decreasing trends of UVI ranging from -1.96 to 0.41 facilitated the delineation of areas (domains) where UVI are increasing or decreasing. The domain of UVI increase occupies the central and southern (S) parts, and the domains of decrease cover the northern (N) and S parts of the Kerala region. The rate of change of daily UVI in domain of increase and decrease shows an average rate of 0.34 × 10-5 day-1 and -2 × 10-5 day-1, respectively. The parameters (rainfall, air temperature, cloud optical depth (COD) and solar zenith angle (SZA)) that affect the strength of UV rays reaching the surface indicate that a cloud-free atmosphere or low thickness clouds prevails in the Kerala region. Overall, the study results indicate the need for regular monitoring of UVI in the study area and also suggest appropriate campaigns to disseminate information and precautions for prolonged UVI exposure to reduce the adverse health effects, since the study area has a high population density.
    Matched MeSH terms: Ultraviolet Rays
  13. Quetglas-Llabrés MM, Quispe C, Herrera-Bravo J, Catarino MD, Pereira OR, Cardoso SM, et al.
    Oxid Med Cell Longev, 2022;2022:8615242.
    PMID: 35509838 DOI: 10.1155/2022/8615242
    Bergapten (BP) or 5-methoxypsoralen (5-MOP) is a furocoumarin compound mainly found in bergamot essential oil but also in other citrus essential oils and grapefruit juice. This compound presents antibacterial, anti-inflammatory, hypolipemic, and anticancer effects and is successfully used as a photosensitizing agent. The present review focuses on the research evidence related to the therapeutic properties of bergapten collected in recent years. Many preclinical and in vitro studies have been evidenced the therapeutic action of BP; however, few clinical trials have been carried out to evaluate its efficacy. These clinical trials with BP are mainly focused on patients suffering from skin disorders such as psoriasis or vitiligo. In these trials, the administration of BP (oral or topical) combined with UV irradiation induces relevant lesion clearance rates. In addition, beneficial effects of bergamot extract were also observed in patients with altered serum lipid profiles and in people with nonalcoholic fatty liver. On the contrary, there are no clinical trials that investigate the possible effects on cancer. Although the bioavailability of BP is lower than that of its 8-methoxypsoralen (8-MOP) isomer, it has fewer side effects allowing higher concentrations to be administered. In conclusion, although the use of BP has therapeutic applications on skin disorders as a sensitizing agent and as components of bergamot extract as hypolipemic therapy, more trials are necessary to define the doses and treatment guidelines and its usefulness against other pathologies such as cancer or bacterial infections.
    Matched MeSH terms: Ultraviolet Rays
  14. Ramli ZA, Asim N, Isahak WN, Emdadi Z, Ahmad-Ludin N, Yarmo MA, et al.
    ScientificWorldJournal, 2014;2014:415136.
    PMID: 25013855 DOI: 10.1155/2014/415136
    This study involves the investigation of altering the photocatalytic activity of TiO2 using composite materials. Three different forms of modified TiO2, namely, TiO2/activated carbon (AC), TiO2/carbon (C), and TiO2/PANi, were compared. The TiO2/carbon composite was obtained by pyrolysis of TiO2/PANi prepared by in situ polymerization method, while the TiO2/activated carbon (TiO2/AC) was obtained after treating TiO2/carbon with 1.0 M KOH solution, followed by calcination at a temperature of 450°C. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), thermogravimetric analysis (TG-DTA), Brunauer-Emmet-Teller (BET), and UV-Vis spectroscopy were used to characterize and evaluate the prepared samples. The specific surface area was determined to be in the following order: TiO2/AC > TiO2/C > TiO2/PANi > TiO2 (179 > 134 > 54 > 9 m(2) g(-1)). The evaluation of photocatalytic performance for the degradation of methylene blue under UV light irradiation was also of the same order, with 98 > 84.7 > 69% conversion rate, which is likely to be attributed to the porosity and synergistic effect in the prepared samples.
    Matched MeSH terms: Ultraviolet Rays*
  15. Kuan YH, Bhat R, Karim AA
    J Agric Food Chem, 2011 Apr 27;59(8):4111-8.
    PMID: 21401213 DOI: 10.1021/jf104050k
    The physicochemical and functional properties of ultraviolet (UV)-treated egg white protein (EW) and sodium caseinate (SC) were investigated. UV irradiation of the proteins was carried out for 30, 60, 90, and 120 min. However, the SC samples were subjected to extended UV irradiation for 4 and 6 h as no difference was found on the initial UV exposure time. Formol titration, SDS-PAGE, and FTIR analyses indicated that UV irradiation could induce cross-linking on proteins and led to improved emulsifying and foaming properties (P < 0.05). These results indicated that the UV-irradiated EW and SC could be used as novel emulsifier and foaming agents in broad food systems for stabilizing and foaming purposes.
    Matched MeSH terms: Ultraviolet Rays*
  16. Dzinun H, Othman MHD, Ismail AF
    Chemosphere, 2019 Aug;228:241-248.
    PMID: 31035161 DOI: 10.1016/j.chemosphere.2019.04.118
    Comparison studies in suspension and hybrid photocatalytic membrane reactor (HPMR) system was investigated by using Reactive Black 5 (RB5) as target pollutant under UVA light irradiation. To achieve this aim, hybrid TiO2/clinoptilolite (TCP) photocatalyst powder was prepared by solid-state dispersion (SSD) methods and embedded at the outer layer of dual layer hollow fiber (DLHF) membranes fabricated via single step co-spinning process. TiO2 and CP photocatalyst were also used as control samples. The samples were characterized by Scanning Electron Microscopy (SEM), Energy Dispersion of X-ray (EDX), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) analyses. The result shows that TCP was actively functioned as photocatalyst in suspension system and 86% of RB5 photocatalytic degradation achieved within 60 min; however the additional step is required to separate the catalyst with treated water. In the HPMR system, even though the RB5 photocatalytic degradation exhibits lower efficiency however the rejection of RB5 was achieved up to 95% under UV irradiation due to the properties of photocatalytic membranes. The well dispersed of TCP at the outer layer of DLHF membrane have improved the surface affinity of DL-TCP membrane towards water, exhibit the highest pure water flux of 41.72 L/m2.h compared to DL-TiO2 membrane. In general, CP can help on improving photocatalytic activity of TiO2 in suspension, increased the RB5 removal and the permeability of DLHF membrane in HPMR system as well.
    Matched MeSH terms: Ultraviolet Rays*
  17. Yong SS, Han WH, Faheem NAA, Puvan N, Tan LL, Wong SM, et al.
    Photodermatol Photoimmunol Photomed, 2022 Nov;38(6):541-547.
    PMID: 35324018 DOI: 10.1111/phpp.12787
    BACKGROUND: Airline pilots face significant ultraviolet radiation exposure resulting in an increased risk of sun damage and skin cancers. We aimed to evaluate sun-protective practices and associated factors among airline pilots.

    METHODS: We disseminated an online questionnaire evaluating the use of sunscreen, sunglasses, hats and protective clothing during daytime hours in the cockpit and during outdoor activities to 346 global commercial airline pilots, and we received 220 completed responses. The Pearson chi-squared test or Fisher's exact test where necessary were used to determine possible factors associated with the use of sun-protective practices. Potential confounders were adjusted for using multivariate analyses.

    RESULTS: The most common sun protective behaviour was the wearing of sunglasses during daytime flights (89.5%), followed by the use of caps during outdoor activities (47.7%). More pilots applied sunscreen during daytime flights (14.1%) compared with walk-arounds (8.2%). Males were less likely to use sunscreen during flights (adjusted odds ratio, aOR = 0.76), use sunscreen for walk-arounds (aOR = 0.175) and wear long sleeves (aOR = 0.013). Pilots who flew less than 30 h a month in high latitude regions were less likely to use a cap or hat outdoors (aOR = 0.419) or use sunscreen during walk-arounds (aOR = 0.241). Younger pilots were also less likely to use caps or hats outdoors (aOR = 0.446).

    CONCLUSION: Male pilots and those who spent less time in high latitudes were less likely to practice sun protection. Targeted educational efforts may be implemented to reduce occupational ultraviolet exposure.

    Matched MeSH terms: Ultraviolet Rays/adverse effects
  18. Ghasemzadeh A, Ashkani S, Baghdadi A, Pazoki A, Jaafar HZ, Rahmat A
    Molecules, 2016 Sep 09;21(9).
    PMID: 27618000 DOI: 10.3390/molecules21091203
    Sweet basil (Ocimum basilicum Linnaeus) is aromatic herb that has been utilized in traditional medicine. To improve the phytochemical constituents and pharmaceutical quality of sweet basil leaves, ultraviolet (UV)-B irradiation at different intensities (2.30, 3.60, and 4.80 W/m²) and durations (4, 6, 8, and 10-h) was applied at the post-harvest stage. Total flavonoid content (TFC) and total phenolic content (TPC) were measured using spectrophotometric method, and individual flavonoids and phenolic acids were identified using ultra-high performance liquid chromatography. As a key enzyme for the metabolism of flavonoids, chalcone synthase (CHS) activity, was measured using a CHS assay. Antioxidant activity and antiproliferative activity of extracts against a breast cancer cell line (MCF-7) were evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, respectively. UV-B irradiation at an intensity of 3.60 W/m² increased TFC approximately 0.85-fold and also increased quercetin (0.41-fold), catechin (0.85-fold), kaempferol (0.65-fold) rutin (0.68-fold) and luteolin (1.00-fold) content. The highest TPC and individual phenolic acid (gallic acid, cinnamic acid and ferulic acid) was observed in the 3.60 W/m² of UV-B treatment. Cinnamic acid and luteolin were not detected in the control plants, production being induced by UV-B irradiation. Production of these secondary metabolites was also significantly influenced by the duration of UV-B irradiation. Irradiation for 8-h led to higher TFC, TPC and individual flavonoids and phenolic acids than for the other durations (4, 8, and 10-h) except for cinnamic acid, which was detected at higher concentration when irradiated for 6-h. Irradiation for 10-h significantly decreased the secondary metabolite production in sweet basil leaves. CHS activity was induced by UV-B irradiation and highest activity was observed at 3.60 W/m² of UV-B irradiation. UV-B treated leaves presented the highest DPPH activity and antiproliferative activity with a half-maximal inhibitory concentration (IC50) value of 56.0 and 40.8 µg/mL, respectively, over that of the control plants (78.0 and 58.2 µg/mL, respectively). These observations suggest that post-harvest irradiation with UV-B can be considered a promising technique to improve the healthy-nutritional and pharmaceutical properties of sweet basil leaves.
    Matched MeSH terms: Ultraviolet Rays*
  19. Yousif E, Ahmed DS, Ahmed AA, Hameed AS, Muhamed SH, Yusop RM, et al.
    Environ Sci Pollut Res Int, 2019 Apr;26(10):9945-9954.
    PMID: 30739295 DOI: 10.1007/s11356-019-04323-x
    Although plastic induces environmental damages, almost the consumption of poly(vinyl chloride) never stops increasing. Therefore, this work abstracted by two parts, first, synthesis of Schiff bases 1-4 compounds through the reaction of amino group with appropriate aromatic aldehyde, reaction of PVC with Schiff bases compounds 1-4 in THF to form a new modified PVC-1, PVC-2, PVC-3, and PVC-4. The structures of Schiff bases 1-4 and the modified PVC-1, PVC-2, PVC-3, and PVC-4 have been characterized by different spectroscopic analyses. Second, the influence of introducing 4-amino-1,2,4-triazole as a pendent groups into PVC chain investigated on photostability rules of tests. The modified polymers photostability investigated by observing indices (ICO, Ipo, and IOH), weight loss, UV and morphological studies, and all results obtained indicated that PVC-1, PVC-2, PVC-3 and PVC-4 gave lower growth rate of ICO, IPO, and IOH through UV exposure time. The photostability are given as PVC-4 
    Matched MeSH terms: Ultraviolet Rays*
  20. Bais AF, Bernhard G, McKenzie RL, Aucamp PJ, Young PJ, Ilyas M, et al.
    Photochem Photobiol Sci, 2019 Mar 01;18(3):602-640.
    PMID: 30810565 DOI: 10.1039/c8pp90059k
    This report assesses the effects of stratospheric ozone depletion and anticipated ozone recovery on the intensity of ultraviolet (UV) radiation at the Earth's surface. Interactions between changes in ozone and changes in climate, as well as their effects on UV radiation, are also considered. These evaluations focus mainly on new knowledge gained from research conducted during the last four years. Furthermore, drivers of changes in UV radiation other than ozone are discussed and their relative importance is assessed. The most important of these factors, namely clouds, aerosols and surface reflectivity, are related to changes in climate, and some of their effects on short- and long-term variations of UV radiation have already been identified from measurements. Finally, projected future developments in stratospheric ozone, climate, and other factors affecting UV radiation have been used to estimate changes in solar UV radiation from the present to the end of the 21st century. New instruments and methods have been assessed with respect to their ability to provide useful and accurate information for monitoring solar UV radiation at the Earth's surface and for determining relevant exposures of humans. Evidence since the last assessment reconfirms that systematic and accurate long-term measurements of UV radiation and stratospheric ozone are essential for assessing the effectiveness of the Montreal Protocol and its Amendments and adjustments. Finally, we have assessed aspects of UV radiation related to biological effects and human health, as well as implications for UV radiation from possible solar radiation management (geoengineering) methods to mitigate climate change.
    Matched MeSH terms: Ultraviolet Rays*
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