Displaying publications 21 - 40 of 141 in total

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  1. Potential toxic effects of chlorination and UV/chlorination in the treatment of hydrochlorothiazide in the water
    Mansor NA, Tay KS
    Sci Total Environ, 2020 Apr 20;714:136745.
    PMID: 31982754 DOI: 10.1016/j.scitotenv.2020.136745
    Chlorination is a common disinfection method in water treatment. This method can be converted into an advanced oxidation process by incorporating UV irradiation during water treatment. This study investigated the degradation of hydrochlorothiazide (HCTZ) by chlorination and UV/chlorination in water. HCTZ is a diuretic medication that has been frequently detected in wastewater. For chlorination, the second-order rate constant for the reaction between HCTZ with free available chlorine was found to increase with increasing pH from 5 to 8 due to the increase of the anionic HCTZ fraction. UV/chlorination was found to be more efficient in removing HCTZ as compared with chlorination due to the presence of reactive radical species such as hydroxyl radicals. For transformation by-products, chlorination was found to produce two by-products via chlorination and hydroxylation reactions that occurred at the aromatic ring of HCTZ. For UV/chlorination, an additional by-product formed through a radical reaction at the heterocyclic moiety of HCTZ was detected. Based on the Escherichia coli inhibition study, chlorination and UV/chlorination were found to increase the toxicity of the HCTZ solution. This result indicated that even UV/chlorination showed higher effectiveness in removing HCTZ; however, it also has the potential to generate toxic by-products and effluent.
    Matched MeSH terms: Ultraviolet Rays
  2. Degradation of 5,5-diphenylhydantoin by chlorination and UV/chlorination: kinetics, transformation by-products, and toxicity assessment
    Mansor NA, Tay KS
    Environ Sci Pollut Res Int, 2017 Oct;24(28):22361-22370.
    PMID: 28801887 DOI: 10.1007/s11356-017-9892-6
    This study investigated the reaction kinetics and mechanism of the degradation of 5,5-diphenylhydantoin (DPH) during conventional chlorination and UV/chlorination. DPH is one of the antiepileptic drugs, which has frequently been detected in the aquatic environment. For chlorination, the second-order rate constant for the reaction between DPH and free active chlorine (FAC) was determined at pH 5 to 8. At pH 6 to 8, the efficiency of chlorination in the removal of DPH was found to be dominated by the reaction involving hypochlorous acid (HOCl). The result also showed that anionic species of DPH was more reactive toward FAC as compared with neutral DPH. For UV/chlorination, the effect of FAC dosage and pH on the degradation of DPH was evaluated. UV/chlorination is a more effective method for removing DPH as compared with conventional chlorination and UV irradiation. The DPH degradation rate was found to increase with increasing FAC concentration. On the other hand, the degradation of DPH was found to be more favorable under the acidic condition. Based on the identified transformation by-products, DPH was found to be degraded through the reaction at imidazolidine-2,4-dione moiety of DPH for both chlorination and UV/chlorination. Toxicity study on the chlorination and UV/chlorination-treated DPH solutions suggested that UV/chlorination is a more efficient method for reducing the toxicity of DPH.
    Matched MeSH terms: Ultraviolet Rays*
  3. Fulltext Nanolayered composite with enhanced ultraviolet ray absorption properties from simultaneous intercalation of sunscreen molecules
    Megat Nabil Mohsin S, Hussein MZ, Sarijo SH, Fakurazi S, Arulselvan P, Taufiq-Yap YH
    Int J Nanomedicine, 2018;13:6359-6374.
    PMID: 30349255 DOI: 10.2147/IJN.S171390
    Introduction: The potential of layered double hydroxide (LDH) as a host of multiple ultraviolet-ray absorbers was investigated by simultaneous intercalation of benzophenone 4 (B4) and Eusolex® 232 (EUS) in Zn/Al LDH.

    Methods: The nanocomposites were prepared via coprecipitation method at various molar ratios of B4 and EUS.

    Results: At equal molar ratios, the obtained nanocomposite showed an intercalation selectivity that is preferential to EUS. However, the selectivity ratio of intercalated anions was shown to be capable of being altered by adjusting the molar ratio of intended guests during synthesis. Dual-guest nanocomposite synthesized with B4:EUS molar ratio 3:1 (ZEB [3:1]) showed an intercalation selectivity ratio of B4:EUS =53:47. Properties of ZEB (3:1) were monitored using powder X-ray diffractometer to show a basal spacing of 21.8 Å. Direct-injection mass spectra, Fourier transform infrared spectra, and ultraviolet-visible spectra confirmed the dual intercalation of both anions into the interlayer regions of dual-guest nanocomposite. The cytotoxicity study of dual-guest nanocomposite ZEB (3:1) on human dermal fibroblast cells showed no significant toxicity until 25 μg/mL.

    Conclusion: Overall, the findings demonstrate successful customization of ultraviolet-ray absorbers composition in LDH host.

    Matched MeSH terms: Ultraviolet Rays*
  4. Impact of UV radiation on Mxene-mediated tubulin dissociation and mitochondrial apoptosis in breast cancer cells
    Tan EW, Simon SE, Numan A, Khalid M, Tan KO
    Colloids Surf B Biointerfaces, 2024 Mar;235:113793.
    PMID: 38364521 DOI: 10.1016/j.colsurfb.2024.113793
    Breast cancer is a global health concern that requires personalized therapies to prevent relapses, as conventional treatments may develop resistance over time. Photothermal therapy using spectral radiation or intense light emission is a broad-spectrum treatment that induces hyperthermia-mediated cancer cell death. MXene, a two-dimensional material, has been reported to have potential biological applications in photothermal therapy for cancer treatment. In this study, we investigated the apoptotic activity of MXene and UV-irradiated MXene in MCF-7 breast cancer cells by treating them with varying concentrations of MXene. The cytotoxicity of MXene and UV was evaluated by analyzing cellular morphology, nuclei condensation, caspase activation, and apoptotic cell death. We also assessed the effect of the combined treatment on the expression and cellular distribution of Tubulin, a key component of microtubules required for cell division. At low concentrations of MXene (up to 100 µg/ml), the level of cytotoxicity in MCF-7 cells was low. However, the combined treatment of MXene and UV resulted in a synergistic increase in cytotoxicity, causing rounded cellular morphology, condensed nuclei, caspase activation, and apoptotic cell death. Furthermore, the treatment reduced Tubulin protein expression and cellular distribution, indicating a potent inducer of cell death with potential application for cancer treatment. The study demonstrates that the combined treatment of MXene and UVB irradiation is a promising strategy for inducing apoptotic cell death in breast cancer cells, suggesting its potential as a therapeutic intervention for breast cancer.
    Matched MeSH terms: Ultraviolet Rays*
  5. Fulltext Improving Vesicular Integrity and Antioxidant Activity of Novel Mixed Soy Lecithin-Based Liposomes Containing Squalene and Their Stability against UV Light
    Toopkanloo SP, Tan TB, Abas F, Azam M, Nehdi IA, Tan CP
    Molecules, 2020 Dec 11;25(24).
    PMID: 33322600 DOI: 10.3390/molecules25245873
    In order to improve the membrane lipophilicity and the affinity towards the environment of lipid bilayers, squalene (SQ) could be conjugated to phospholipids in the formation of liposomes. The effect of membrane composition and concentrations on the degradation of liposomes prepared via the extrusion method was investigated. Liposomes were prepared using a mixture of SQ, cholesterol (CH) and Tween80 (TW80). Based on the optimal conditions, liposome batches were prepared in the absence and presence of SQ. Their physicochemical and stability behavior were evaluated as a function of liposome constituent. From the optimization study, the liposomal formulation containing 5% (w/w) mixed soy lecithin (ML), 0.5% (w/w) SQ, 0.3% (w/w) CH and 0.75% (w/w) TW80 had optimal physicochemical properties and displayed a unilamellar structure. Liposome prepared using the optimal formulation had a low particle size (158.31 ± 2.96 nm) and acceptable %increase in the particle size (15.09% ± 3.76%) and %trolox equivalent antioxidant capacity (%TEAC) loss (35.69% ± 0.72%) against UV light treatment (280-320 nm) for 6 h. The interesting outcome of this research was the association of naturally occurring substance SQ for size reduction without the extra input of energy or mechanical procedures, and improvement of vesicle stability and antioxidant activity of ML-based liposome. This study also demonstrated that the presence of SQ in the membrane might increase the acyl chain dynamics and decrease the viscosity of the dispersion, thereby limiting long-term stability of the liposome.
    Matched MeSH terms: Ultraviolet Rays
  6. Medically important solar ultraviolet A. Radiation measurements
    Ilyas M, Abdul Aziz D, Tajuddin MR
    Int J Dermatol, 1988 Jun;27(5):315-8.
    PMID: 3391727
    Results from a 6-year study of solar ultraviolet A (UVA) radiation measurements at the equatorial location of Penang (5 degrees N) are presented. On clear days, the diurnal flux reaches a very high dosage of about 3.0 x 10(-2) KWHM-2 around midday. The average daily total flux is in the range of 1.6 x 10(-1) KWHM-2 and does not change much seasonally. The high 83% cloud cover only reduces the incoming flux to about half. The radiation flux represents a lower limit of the incident UVA radiation applicable to much of the equatorial/tropical region.
    Matched MeSH terms: Ultraviolet Rays*
  7. Fulltext Enhancement of astaxanthin accumulation using black light in Coelastrum and Monoraphidium isolated from Malaysia
    Kaha M, Iwamoto K, Yahya NA, Suhaimi N, Sugiura N, Hara H, et al.
    Sci Rep, 2021 06 03;11(1):11708.
    PMID: 34083633 DOI: 10.1038/s41598-021-91128-z
    Microalgae are important microorganisms which produce potentially valuable compounds. Astaxanthin, a group of xanthophyll carotenoids, is one of the most powerful antioxidants mainly found in microalgae, yeasts, and crustaceans. Environmental stresses such as intense light, drought, high salinity, nutrient depletion, and high temperature can induce the accumulation of astaxanthin. Thus, this research aims to investigate the effect of black light, also known as long-wave ultraviolet radiation or UV-A, as a stressor on the accumulation of astaxanthin as well as to screen the antioxidant property in two tropical green algal strains isolated from Malaysia, Coelastrum sp. and Monoraphidium sp. SP03. Monoraphidium sp. SP03 showed a higher growth rate (0.66 day-1) compared to that of Coelastrum sp. (0.22 day-1). Coelastrum sp. showed significantly higher accumulation of astaxanthin in black light (0.999 g mL culture-1) compared to that in control condition (0.185 g mL-1). Similarly, Monoraphidium sp. SP03 showed higher astaxanthin content in black light (0.476 g mL culture-1) compared to that in control condition (0.363 g mL culture-1). Coelastrum sp. showed higher scavenging activity (30.19%) when cultured in black light condition, indicating a correlation between the antioxidant activity and accumulation of astaxanthin. In this study, black light was shown to possess great potential to enhance the production of astaxanthin in microalgae.
    Matched MeSH terms: Ultraviolet Rays
  8. Impact of ozonation, anion exchange resin and UV/H2O2 pre-treatments to control fouling of ultrafiltration membrane for drinking water treatment
    Pramanik BK, Pramanik SK, Sarker DC, Suja F
    Environ Technol, 2017 Jun;38(11):1383-1389.
    PMID: 27587007 DOI: 10.1080/09593330.2016.1228701
    The effects of ozonation, anion exchange resin (AER) and UV/H2O2 were investigated as a pre-treatment to control organic fouling (OF) of ultrafiltration membrane in the treatment of drinking water. It was found that high molecular weight (MW) organics such as protein and polysaccharide substances were majorly responsible for reversible fouling which contributed to 90% of total fouling. The decline rate increased with successive filtration cycles due to deposition of protein content over time. All pre-treatment could reduce the foulants of a Ultrafiltration membrane which contributed to the improvement in flux, and there was a greater improvement of flux by UV/H2O2 (61%) than ozonation (43%) which in turn was greater than AER (23%) treatment. This was likely due to the effective removal/breakdown of high MW organic content. AER gave greater removal of biofouling potential components (such as biodegradable dissolved organic carbon and assimilable organic carbon contents) compared to UV/H2O2 and ozonation treatment. Overall, this study demonstrated the potential of pre-treatments for reducing OF of ultrafiltration for the treatment of drinking water.
    Matched MeSH terms: Ultraviolet Rays*
  9. Biosynthesis and mobilization of poly(3-hydroxybutyrate) [P(3HB)] by Spirulina platensis
    Jau MH, Yew SP, Toh PS, Chong AS, Chu WL, Phang SM, et al.
    Int J Biol Macromol, 2005 Aug;36(3):144-51.
    PMID: 16005060
    Three strains of Spirulina platensis isolated from different locations showed capability of synthesizing poly(3-hydroxybutyrate) [P(3HB)] under nitrogen-starved conditions with a maximum accumulation of up to 10 wt.% of the cell dry weight (CDW) under mixotrophic culture conditions. Intracellular degradation (mobilization) of P(3HB) granules by S. platensis was initiated by the restoration of nitrogen source. This mobilization process was affected by both illumination and culture pH. The mobilization of P(3HB) was better under illumination (80% degradation) than in dark conditions (40% degradation) over a period of 4 days. Alkaline conditions (pH 10-11) were optimal for both biosynthesis and mobilization of P(3HB) at which 90% of the accumulated P(3HB) was mobilized. Transmission electron microscopy (TEM) revealed that the mobilization of P(3HB) involved changes in granule quantity and morphology. The P(3HB) granules became irregular in shape and the boundary region was less defined. In contrast to bacteria, in S. platensis the intracellular mobilization of P(3HB) seems to be faster than the biosynthesis process. This is because in cyanobacteria chlorosis delays the P(3HB) accumulation process.
    Matched MeSH terms: Ultraviolet Rays
  10. Fulltext Sterilisation of Lucilia cuprina Wiedemann maggots used in therapy of intractable wounds
    Mohd Masri S, Nazni WA, Lee HL, T Rogayah TA, Subramaniam S
    Trop Biomed, 2005 Dec;22(2):185-9.
    PMID: 16883286 MyJurnal
    Three new techniques of sterilising maggots of Lucilia cuprina for the purpose of debriding intractable wounds were studied. These techniques were utilisation of ultra-violet C (UVC) and maggot sterilisation with disinfectants. The status of sterility was checked on nutrient agar and blood agar and confirmed with staining. The indicators for the effectiveness of the methods were sterility and survival rate of the eggs or larvae. Egg sterilisation with UVC had the lowest hatching rate (16+/-0.00%) while egg sterilisation with disinfectants showed high hatching rate (36.67+/-4.41%) but low maggot survival rate (31.67+/-1.67%). Sterilisation of the maggots was the most suitable, since the survival rate was the highest (88.67+/-0.88%). Complete sterility was achieved in all cases, except that Proteus mirabilis was consistently found. However, the presence of this microorganism was considered beneficial.
    Matched MeSH terms: Ultraviolet Rays
  11. Impact of ultraviolet radiation treatments on the physicochemical properties, antioxidants, enzyme activity and microbial load in freshly prepared hand pressed strawberry juice
    Bhat R, Stamminger R
    Food Sci Technol Int, 2015 Jul;21(5):354-63.
    PMID: 24867944 DOI: 10.1177/1082013214536708
    Freshly prepared, hand-pressed strawberry fruit juice was exposed to ultraviolet radiation (254 nm) at room temperature (25 ℃ ± 1 ℃) for 15, 30 and 60 min with 0 min serving as control. Results revealed decrease in pH, total soluble solids and titratable acidity, while colour parameters (L*, a* and b* values) and clarity of juice (% transmittance) increased significantly. All the results corresponded to exposure time to ultraviolet radiation. Bioactive compounds (total phenolics, ascorbic acid and anthocyanins) decreased along with a recorded reduction in polyphenol oxidase enzyme and 1,1-diphenyl-2-picryl hydrazyl radical scavenging activities, which were again dependent on exposure time. Results on the microbial studies showed significant reduction by 2-log cycles in aerobic plate count as well as in total yeast and mould counts. Though negative results were observed for certain parameters, this is the first time it was endeavoured to demonstrate the impact of ultraviolet radiation radiation on freshly prepared, hand-pressed strawberries juice.
    Matched MeSH terms: Ultraviolet Rays*
  12. Fulltext Photocatalytic degradation of methylene blue under UV light irradiation on prepared carbonaceous TiO2
    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*
  13. Effects of ultraviolet light (UV-C) and heat treatment on the quality of fresh-cut Chokanan mango and Josephine pineapple
    George DS, Razali Z, Santhirasegaram V, Somasundram C
    J Food Sci, 2015 Feb;80(2):S426-34.
    PMID: 25586772 DOI: 10.1111/1750-3841.12762
    The effects of ultraviolet (UV-C) and medium heat (70 °C) treatments on the quality of fresh-cut Chokanan mango and Josephine pineapple were investigated. Quality attributes included physicochemical properties (pH, titratable acidity, and total soluble solids), ascorbic acid content (vitamin C), antioxidant activity, as well as microbial inactivation. Consumers' acceptance was also investigated through sensory evaluation of the attributes (appearance, texture, aroma and taste). Furthermore, shelf-life study of samples stored at 4 ± 1 °C was conducted for 15 d. The fresh-cut fruits were exposed to UV-C for 0, 15, 30, and 60 min while heat treatments were carried out at 70 °C for 0, 5, 10 and 20 min. Both UV-C and medium heat treatments resulted in no significant changes to the physicochemical attributes of both fruits. The ascorbic acid content of UV-C treated fruits was unaffected; however, medium heat treatment resulted in deterioration of ascorbic acids in both fruits. The antioxidants were enhanced with UV-C treatment which could prove invaluable to consumers. Heat treatments on the other hand resulted in decreased antioxidant activities. Microbial count in both fruits was significantly reduced by both treatments. The shelf life of the fresh-cut fruits were also successfully extended to a maximum of 15 d following treatments. As for consumers' acceptance, UV-C treated fruits were the most accepted as compared to their heat-treated counterparts. The results obtained through this study support the use of UV-C treatment for better retention of quality, effective microbial inactivation and enhancement of health promoting compounds for the benefit of consumers.
    Matched MeSH terms: Ultraviolet Rays*
  14. Effect of postharvest ultraviolet-C treatment on the proteome changes in fresh cut mango (Mangifera indica L. cv. Chokanan)
    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
  15. Fulltext Effect of thermal and ultraviolet treatments on the stability of antioxidant compounds in single strength pineapple juice throughout refrigerated storage
    Goh, S. G., Noranizan, M., Leong, C. M., Sew C. C., Sobhi, B.
    International Food Research Journal, 2012;19(3):1131-1136.
    MyJurnal
    Thermal treatment is commonly applied in juice manufacturing as a method to pasteurize juices. However the heat may deteriorate some of the essential compounds in the juice, especially heat-sensitive antioxidants. Therefore non-thermal treatment such as ultraviolet (UV) ray has been proposed as an alternative for pasteurization. The objective of this study was to compare the effect of thermal and UV treatments on the content of antioxidants (phenolic acids, flavonoids, carotenoids, ascorbic acids) and antioxidant capacity of single strength pineapple juice. The antioxidants stability of juices throughout 14 days of refrigerated storage was also studied. Ultraviolet treatment shows higher ascorbic acid content after treatment as compared to thermally treated single strength pineapple juice. Storage time affected the studied antioxidants, where UV
    treatment provided better stability to ascorbic acid content while thermal treatment provided better stability to flavonoids and carotenoids.
    Matched MeSH terms: Ultraviolet Rays
  16. Shape-Controlled Fabrication of ZnO Architectures for Palm Oil Mill Effluent Degradation
    Wong KA, Lam SM, Sin JC
    J Nanosci Nanotechnol, 2019 08 01;19(8):5271-5278.
    PMID: 30913844 DOI: 10.1166/jnn.2019.16816
    Shaped-controlled ZnO architectures including spherical, rod, rice-like and flower-like were fabricated via a reflux method in which the morphology, crystallinity, functional group and optical properties were tailored under different pH values in the precursor solution. The photoactivities of the prepared ZnO were evaluated under UV irradiation and the findings implied that the flower-like ZnO synthesized at pH 12 displayed superior activities on palm oil mil effluent degradation than those of other structures. The photocatalytic enhancement of flower-like ZnO was ascribed to its unique architecture, good crystallinity and superior optical properties. The flower-like ZnO with excellent photocatalytic performance have been confirmed by formation of hydroxyl radicals using a terephthalic acid-photoluminescence test. There was an optimal photocatalyst amount of 1.0 g/L, at which a maximum chemical oxygen demand removal of palm oil mill effluent was achieved under exposure of UV light. The phytotoxicity experiment via mung beans demonstrated a decrease in phytotoxicity.
    Matched MeSH terms: Ultraviolet Rays
  17. Applicability of BaTiO3/graphene oxide (GO) composite for enhanced photodegradation of methylene blue (MB) in synthetic wastewater under UV-vis irradiation
    Mengting Z, Kurniawan TA, Fei S, Ouyang T, Othman MHD, Rezakazemi M, et al.
    Environ Pollut, 2019 Dec;255(Pt 1):113182.
    PMID: 31541840 DOI: 10.1016/j.envpol.2019.113182
    Methylene blue (MB) is a dye pollutant commonly present in textile wastewater. We investigate and critically evaluate the applicability of BaTiO3/GO composite for photodegradation of MB in synthetic wastewater under UV-vis irradiation. To enhance its performance, the BaTiO3/GO composite is varied based on the BaTiO3 weight. To compare and evaluate any changes in their morphologies and crystalline structures before and after treatment, BET (Brunauer-Emmett-Teller), XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy) and TEM (transmission electron microscopy) tests are conducted, while the effects of reaction time, pH, dose of photocatalyst and initial MB concentration on its photodegradation by the composite are also investigated under identical conditions. The degradation pathways and removal mechanisms of MB by the BaTiO3/GO are elaborated. It is evident from this study that the BaTiO3/GO composite is promising for MB photodegradation through ·OH. Under optimized conditions (0.5 g/L of dose, pH 9.0, and 5 mg/L of MB concentration), the composite with 1:2 dose ratio of BaTiO3/GO has the highest MB degradation rate (95%) after 3 h of UV vis irradiation. However, its treated effluents still could not comply with the discharge standard limit of less than 0.2 mg/L imposed by national environmental legislation. This suggests that additional biological treatments are still required to deal with the remaining oxidation by-products of MB, still present in the wastewater samples such as 3,7-bis (dimethyl-amino)-10H-phenothiazine 5-oxide.
    Matched MeSH terms: Ultraviolet Rays
  18. Evaluation on the Photocatalytic Degradation Activity of Reactive Blue 4 using Pure Anatase Nano-TiO2
    Joon Ching Juan, Sze Nee Goh, Ta Yeong Wu, Emy Marlina Samsudin, Tan Tong Ling, Sharifah Bee Abd. Hamid
    Sains Malaysiana, 2015;44:1011-1019.
    Disposal of dye wastewater into water streams without treatment endangers human and marine lives. This work focused on the second largest class of textile dyes after azo dyes due to its high resistivity to biodegradation and high toxicity. The photocatalytic degradation of Reactive Blue 4 (RB4), an anthraquinone dye, has been investigated using pure anatase nano titanium (IV) oxide (TiO2). The dye molecules were fully degraded and the addition of hydrogen peroxide (H2O2) enhanced the photodegradation efficiency. It is found that the degradation as the hydroxyl radicals in the bulk solution is sufficient for complete mineralisation. The disappearance of the dye follows pseudo-first-order kinetics. The effect of pH, amount of photocatalyst, UV-light intensity, light source and concentration of hydrogen peroxide was ascertained.
    Matched MeSH terms: Ultraviolet Rays
  19. Fulltext RNA-Seq analysis revealed genes associated with UV-induced cell necrosis through MAPK/TNF-α pathways in human dermal fibroblast cells as an inducer of premature photoaging
    Alafiatayo AA, Lai KS, Ahmad S, Mahmood M, Shaharuddin NA
    Genomics, 2020 01;112(1):484-493.
    PMID: 30946891 DOI: 10.1016/j.ygeno.2019.03.011
    Exposing the skin to solar UV radiation induces cascades of signaling pathways and biological alterations such as redox imbalance, suppression of antioxidant genes and programmed cell death. Therefore, the aim of this study was to use RNA-Seq to unravel the effects of UV radiation on Normal Human Adult Fibroblast cells (NHDF). Cells were exposed to UV (20 mJ/cm2 for 3 mins) and incubated for 24 h. Total mRNA from the cells generated libraries of 72,080,648 and 40,750,939 raw reads from UV-treated and control cells respectively. Of the differentially expressed genes (DEGs) produced 2,007 were up-regulated and 2,791 were down-regulated (fold change ≥2, p 
    Matched MeSH terms: Ultraviolet Rays*
  20. Fulltext Green Synthesis and Characterization of Pullulan Mediated Silver Nanoparticles through Ultraviolet Irradiation
    Khan MJ, Kumari S, Shameli K, Selamat J, Sazili AQ
    Materials (Basel), 2019 Jul 26;12(15).
    PMID: 31357398 DOI: 10.3390/ma12152382
    Nanoparticles (NPs) are, frequently, being utilized in multi-dimensional enterprises. Silver nanoparticles (AgNPs) have attracted researchers in the last decade due to their exceptional efficacy at very low volume and stability at higher temperatures. Due to certain limitations of the chemical method of synthesis, AgNPs can be obtained by physical methods including sun rays, microwaves and ultraviolet (UV) radiation. In the current study, the synthesis of pullulan mediated silver nanoparticles (P-AgNPs) was achieved through ultraviolet (UV) irradiation, with a wavelength of 365 nm, for 96 h. P-AgNPs were formed after 24 h of UV-irradiation time and expressed spectra maxima as 415 nm, after 96 h, in UV-vis spectroscopy. The crystallographic structure was "face centered cubic (fcc)" as confirmed by powder X-ray diffraction (PXRD). Furthermore, high resolution transmission electron microscopy (HRTEM) proved that P-AgNPs were covered with a thin layer of pullulan, with a mean crystalline size of 6.02 ± 2.37. The average lattice fringe spacing of nanoparticles was confirmed as 0.235 nm with quasi-spherical characteristics, by selected area electron diffraction (SAED) analysis. These green synthesized P-AgNPs can be utilized efficiently, as an active food and meat preservative, when incorporated into the edible films.
    Matched MeSH terms: Ultraviolet Rays
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