Displaying publications 1 - 20 of 140 in total

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  1. Fulltext i-Propylammonium Lead Chloride Based Perovskite Photocatalysts for Depolymerization of Lignin Under UV Light
    Kausar S, Altaf AA, Hamayun M, Rasool N, Hadait M, Akhtar A, et al.
    Molecules, 2020 Jul 31;25(15).
    PMID: 32752133 DOI: 10.3390/molecules25153520
    Lignin depolymerization for the purpose of synthesizing aromatic molecules is a growing focus of research to find alternative energy sources. In current studies, the photocatalytic depolymerization of lignin has been investigated by two new iso-propylamine-based lead chloride perovskite nanomaterials (SK9 and SK10), synthesized by the facile hydrothermal method. Characterization was done by Powder X-Ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), UV-Visible (UV-Vis), Photoluminescence (PL), and Fourier-Transform Infrared (FTIR) Spectroscopy and was used for the photocatalytic depolymerization of lignin under UV light. Lignin depolymerization was monitored by taking absorption spectra and catalytic paths studied by applying kinetic models. The %depolymerization was calculated for factors such as catalyst dose variation, initial concentration of lignin, and varying temperatures. Pseudo-second order was the best suited kinetic model, exhibiting a mechanism for lignin depolymerization that was chemically rate controlled. The activation energy (Ea) for the depolymerization reaction was found to be 15 kJ/mol, which is remarkably less than conventional depolymerization of the lignin, i.e., 59.75 kJ/mol, exhibiting significant catalytic efficiencies of synthesized perovskites. Products of lignin depolymerization obtained after photocatalytic activity at room temperature (20 °C) and at 90 °C were characterized by GC-MS analysis, indicating an increase in catalytic lignin depolymerization structural subunits into small monomeric functionalities at higher temperatures. Specifically, 2-methoxy-4-methylphenol (39%), benzene (17%), phenol (10%) and catechol (7%) were detected by GC-MS analysis of lignin depolymerization products.
    Matched MeSH terms: Ultraviolet Rays*
  2. Fulltext ZnCr2O4 Nanoparticles: Facile Synthesis, Characterization, and Photocatalytic Properties
    Mousavi Z, Soofivand F, Esmaeili-Zare M, Salavati-Niasari M, Bagheri S
    Sci Rep, 2016 Feb 01;6:20071.
    PMID: 26832329 DOI: 10.1038/srep20071
    In this work, zinc chromite (ZnCr2O4) nanostructures have been synthesized through co-precipitation method. The effect of various parameters such as alkaline agent, pH value, and capping agent type was investigated on purity, particle size and morphology of samples. It was found that particle size and morphology of the products could be greatly influenced via these parameters. The synthesized products were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), fourier transform infrared (FT-IR) spectra, X-ray energy dispersive spectroscopy (EDS), photoluminescence (PL) spectroscopy, diffuse reflectance spectroscopy (DRS) and vibrating sample magnetometry (VSM). The superhydrophilicity of the calcined oxides was investigated by wetting experiments and a sessile drop technique which carried out at room temperature in air to determine the surface and interfacial interactions. Furthermore, the photocatalytic activity of ZnCr2O4 nanoparticles was confirmed by degradation of anionic dyes such as Eosin-Y and phenol red under UV light irradiation. The obtained ZnCr2O4 nanoparticles exhibit a paramagnetic behavior although bulk ZnCr2O4 is antiferromagnetic, this change in magnetic property can be ascribed to finite size effects.
    Matched MeSH terms: Ultraviolet Rays
  3. Fulltext Viability and Antioxidant Effects of Traditional Cooling Rice Powder (bedak sejuk) Made from Oryza sativa ssp. Indica and Oryza sativa ssp. japonica on UVB-Induced B164A5 Melanoma Cells
    Ghazali AR, Muralitharan RV, Soon CK, Salyam T, Ahmad Maulana NN, Mohamed Thaha UAB, et al.
    Asian Pac J Cancer Prev, 2020 Nov 01;21(11):3381-3386.
    PMID: 33247699 DOI: 10.31557/APJCP.2020.21.11.3381
    BACKGROUND: Traditional cooling rice powder (bedak sejuk) is a fermented rice-based cosmetic that is applied topically on one's skin, as an overnight facial mask. According to user testimonies, bedak sejuk beautifies and whitens skin, whereby these benefits could be utilised as a potential melanoma chemopreventive agent.

    OBJECTIVE: Hence, this study aimed to determine the effects of bedak sejuk made from Oryza sativa ssp. indica (Indica) and Oryza sativa ssp. japonica (Japonica) on UVB-induced B164A5 melanoma cells, and also identify the antioxidant capacities of both types of bedak sejuk.

    METHODS: The optimum dose of Indica and Japonica bedak sejuk to treat the cells was determined via the MTT assay. Then, the antioxidant capacities of both types of bedak sejuk were determined using the FRAP assay.

    RESULTS: From the MTT assay, it was found that Indica and Japonica bedak sejuk showed no cytotoxic effects towards the cells. Hence, no IC50 can be obtained and two of the higher doses, 50 and 100 g/L were chosen for treatment. In the FRAP assay, Indica bedak sejuk at 50 and 100 g/L showed FRAP values of 0.003 ± 0.001 μg AA (ascorbic acid)/g of bedak sejuk and 0.004 ± 0.0003 μg AA/g of bedak sejuk. Whereas Japonica bedak sejuk at 50 g/L had the same FRAP value as Indica bedak sejuk at 100 g/L. As for Japonica bedak sejuk at 100 g/L, it showed the highest antioxidant capacity with the FRAP value of 0.01 ± 0.0007 μg AA/g of bedak sejuk which was statistically significant (p < 0.05) when compared to other tested concentrations.

    CONCLUSION: In conclusion, Japonica bedak sejuk has a higher antioxidant capacity compared to Indica bedak sejuk despite both being not cytotoxic towards the cells. Regardless, further investigations need to be done before bedak sejuk could be developed as potential melanoma chemoprevention agents.

    Matched MeSH terms: Ultraviolet Rays/adverse effects*
  4. Variations of metabolites and proteome in Lonicera japonica Thunb. buds and flowers under UV radiation
    Zhu W, Zheng W, Hu X, Xu X, Zhang L, Tian J
    Biochim Biophys Acta Proteins Proteom, 2017 Apr;1865(4):404-413.
    PMID: 28087425 DOI: 10.1016/j.bbapap.2017.01.004
    Lonicera japonica Thunb., also known as Jin Yin Hua and Japanese honeysuckle, is used as a herbal medicine in Asian countries. Its flowers have been used in folk medicine in the clinic and in making food or healthy beverages for over 1500years in China. To investigate the molecular processes involved in L. japonica development from buds to flowers exposed to UV radiation, a comparative proteomics analysis was performed. Fifty-four proteins were identified as differentially expressed, including 42 that had increased expression and 12 that had decreased expression. The levels of the proteins related to glycolysis, TCA/organic acid transformation, major carbohydrate metabolism, oxidative pentose phosphate, stress, secondary metabolism, hormone, and mitochondrial electron transport were increased during flower opening process after exposure to UV radiation. Six metabolites in L. japonica buds and flowers were identified and relatively quantified using LC-MS/MS. The antioxidant activity was performed using a 1,1-diphenyl-2-picrylhydrazyl assay, which revealed that L. japonica buds had more activity than the UV irradiated flowers. This suggests that UV-B radiation induces production of endogenous ethylene in L. japonica buds, thus facilitating blossoming of the buds and activating the antioxidant system. Additionally, the higher metabolite contents and antioxidant properties of L. japonica buds indicate that the L. japonica bud stage may be a more optimal time to harvest than the flower stage when using for medicinal properties.
    Matched MeSH terms: Ultraviolet Rays*
  5. Fulltext Vacuum ultraviolet field emission lamp consisting of neodymium ion doped lutetium fluoride thin film as phosphor
    Yanagihara M, Tsuji T, Yusop MZ, Tanemura M, Ono S, Nagami T, et al.
    ScientificWorldJournal, 2014;2014:309091.
    PMID: 25302320 DOI: 10.1155/2014/309091
    A vacuum ultraviolet (VUV) field emission lamp was developed by using a neodymium ion doped lutetium fluoride (Nd(3+) : LuF3) thin film as solid-state phosphor and carbon nanofiber field electron emitters. The thin film was synthesized by pulsed laser deposition and incorporated into the lamp. The cathodoluminescence spectra of the lamp showed multiple emission peaks at 180, 225, and 255 nm. These emission spectra were in good agreement with the spectra reported for the Nd(3+) : LuF3 crystal. Moreover, application of an acceleration voltage effectively increased the emission intensity. These results contribute to the performance enhancement of the lamp operating in the VUV region.
    Matched MeSH terms: Ultraviolet Rays
  6. Fulltext Ultraviolet A and Ultraviolet C Light-Induced Reduction of Surface Hydrocarbons on Titanium Implants
    Naauman Z, Rajion ZAB, Maliha S, Hariy P, Muhammad QS, Noor HAR
    Eur J Dent, 2019 Feb;13(1):114-118.
    PMID: 31170762 DOI: 10.1055/s-0039-1688741
    OBJECTIVE: The carbon, titanium, and oxygen levels on titanium implant surfaces with or without ultraviolet (UV) pretreatment were evaluated at different wavelengths through X-ray photoelectron spectroscopy (XPS).

    MATERIALS AND METHODS: This interventional experimental study was conducted on nine Dio UFII implants with hybrid sandblasted and acid-etched (SLA) surface treatments, divided equally into three groups. Control group A samples were not given UV irradiation, while groups B and C samples were given UVA (382 nm, 25 mWcm2) and UVC (260 nm, 15 mWcm2) irradiation, respectively. The atomic ratio of carbon, titanium, and oxygen was compared through XPS.

    RESULTS: Mean carbon-to-titanium ratio and C1 peaks considerably increased in Group A compared to those in experimental Groups B and C. The intensity of Ti2p and O1s peaks was more pronounced for group C compared to that for groups A and B.

    CONCLUSIONS: Although the decrease in surface hydrocarbons was the same in both UV-treated groups, the peak intensity of oxygen increased in the UVC-treated group. Thus, it can be concluded that compared with UVA irradiation, UVC irradiation has the potential to induce more hydrophilicity on SLA-coated implants.

    Matched MeSH terms: Ultraviolet Rays
  7. Fulltext UV/O3 treatment as a surface modification of rice husk towards preparation of novel biocomposites
    Rajendran Royan NR, Sulong AB, Yuhana NY, Chen RS, Ab Ghani MH, Ahmad S
    PLoS One, 2018;13(5):e0197345.
    PMID: 29847568 DOI: 10.1371/journal.pone.0197345
    The use of rice husks (RH) to reinforce polymers in biocomposites are increasing tremendously. However, the incompatibility between the hydrophilic RH fibers and the hydrophobic thermoplastic matrices leads to unsatisfactory biocomposites. Surface modification of the fiber surface was carried out to improve the adhesion between fiber and matrix. In this study, the effect of surface modification of RH via alkali, acid and ultraviolet-ozonolysis (UV/O3) treatments on the properties of composites recycled high density polyethylene (rHDPE) composites was investigated. The untreated and treated RH were characterized by Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM). The composites containing 30 wt% of RH (treated and untreated) were then prepared via extrusion and followed by compression molding. As compared to untreated RH, all surface treated RH exhibited rougher surface and showed improved adhesion with rHDPE matrix. Tensile strength of UV/O3-treated RH composites showed an optimum result at 18.37 MPa which improved about 5% in comparison to the composites filled with untreated RH. UV/O3 treatment promotes shorter processing time and lesser raw material waste during treatment process where this is beneficial for commercialization in the future developments of wood plastic composites (WPCs). Therefore, UV/O3 treatment can be served as an alternative new method to modify RH surface in order to improve the adhesion between hydrophilic RH fibre and hydrophobic rHDPE polymer matrix.
    Matched MeSH terms: Ultraviolet Rays*
  8. UV-blocking and photocatalytic properties of Ag-coated cotton fabrics with Si binders for photo-degradation of recalcitrant dyes in aqueous solutions under sunlight
    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*
  9. Fulltext UV induced surface modification on improving the cytocompatibility of metallocene polyethylene
    Jaganathan SK, Prasath MM
    An Acad Bras Cienc, 2018 4 12;90(1):195-204.
    PMID: 29641759 DOI: 10.1590/0001-3765201820170736
    Demand for medical implants is rising day by day as the world becomes the place for more diseased and older people. Accordingly, in this research, metallocene polyethylene (mPE), a commonly used polymer was treated with UV rays for improving its biocompatibility. Scanning electron microscopy (SEM) images confirmed the formation of crests and troughs, which depicts the improvement of surface roughness of mPE substrates caused by UV etching. Accordingly, the contact angle measurements revealed that the wettability of mPE-2.5 J/cm2 (68.09º) and mPE-5 J/cm2 (57.93º) samples were found to be increased compared to untreated mPE (86.84º) indicating better hydrophilicity. Further, the UV treated surface exhibited enhanced blood compatibility as determined in APTT (untreated mPE- 55.3 ± 2.5 s, mPE-2.5 J/cm2 - 76.7 ± 4.1 s and mPE-5 J/cm2 - 112.3 ± 2 s) and PT (untreated mPE - 24.7 ± 1.5 s, mPE- 2.5 J/cm2 - 34.3 ± 1.1 s and mPE-5 J/cm2 - 43 ± 2 s) assay. Moreover, the treated mPE-2.5 J/cm2 (4.88%) and mPE-5 J/cm2 (1.79%) showed decreased hemolytic percentage compared to untreated mPE (15.40%) indicating better safety to red blood cells. Interestingly, the changes in physicochemical properties of mPE are directly proportional to the dosage of the UV rays. UV modified mPE surfaces were found to be more compatible as identified through MTT assay, photomicrograph and SEM images of the seeded 3T3 cell population. Hence UV-modified surface of mPE may be successfully exploited for medical implants.
    Matched MeSH terms: Ultraviolet Rays*
  10. UV and solar-based photocatalytic degradation of organic pollutants from ceramics industrial wastewater by Fe-doped ZnS nanoparticles
    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
  11. Fulltext Transparent Blend of Poly(Methylmethacrylate)/Cellulose Acetate Butyrate for the Protection from Ultraviolet
    Mahmood Raouf R, Abdul Wahab Z, Azowa Ibrahim N, Abidin Talib Z, Chieng BW
    Polymers (Basel), 2016 Apr 14;8(4).
    PMID: 30979233 DOI: 10.3390/polym8040128
    The use of transparent polymers as an alternative to glass has become widespread. However, the direct exposure of these materials to climatic conditions of sunlight and heat decrease the lifetime cost of these products. The aim of this study was to minimize the harm caused by ultraviolet (UV) radiation exposure to transparent poly(methylmethacrylate) (PMMA), which usually leads to changes in the physical and chemical properties of these materials and reduced performance. This was achieved using environmentally friendly cellulose acetate butyrate (CAB). The optical, morphological, and thermal properties of CAB blended with transparent PMMA was studied using UV-VIS spectrophotometry, scanning electron microscopy, X-ray diffraction, dynamic mechanical analysis, and thermal gravimetric analysis. The results show that CAB was able to reduce the effects of UV radiation by making PMMA more transparent to UV light, thereby preventing the negative effects of trapped radiation within the compositional structure, while maintaining the amorphous structure of the blend. The results also show that CAB blended with PMMA led to some properties commensurate with the requirements of research in terms of a slight increase in the value of the modulus and the glass transition temperature for the PMMA/CAB blend.
    Matched MeSH terms: Ultraviolet Rays
  12. Fulltext Towards producing novel fish gelatin films by combination treatments of ultraviolet radiation and sugars (ribose and lactose) as cross-linking agents
    Bhat R, Karim AA
    J Food Sci Technol, 2014 Jul;51(7):1326-33.
    PMID: 24966426 DOI: 10.1007/s13197-012-0652-9
    Developing novel fish gelatin films with better mechanical properties than mammalian gelatin is a challenging but promising endeavor. Studies were undertaken to produce fish gelatin films by combining treatments with different sugars (ribose and lactose) followed 'by' 'and' ultraviolet (UV) radiation, as possible cross-linking agents. Increase in tensile strength and percent elongation at break was recorded, which was more significant in films without sugars that were exposed to UV radiation. Films with added ribose showed decreased solubility after UV treatment and exhibited higher swelling percentage than films with added lactose, which readily dissolved in water. FTIR spectra of all the films showed identical patterns, which indicated no major changes to have occurred in the functional groups as a result of interaction between gelatin, sugars and UV irradiation. The results of this study could be explored for commercial use, depending on industrial needs for either production of edible films or for food packaging purposes.
    Matched MeSH terms: Ultraviolet Rays
  13. The study of dipole moment of some substituted acetic acids in an electronically excited state
    Murthy MB, Daya Sagar BS, Patil RL
    Spectrochim Acta A Mol Biomol Spectrosc, 2003 Apr;59(6):1277-80.
    PMID: 12659896
    The electronic absorption spectra of eight substituted acetic acids have been measured at room temperature in several solvents. The ground state dipole moments are evaluated experimentally for these molecules. These ground state values are used in conjunction with the spectral results to evaluate their first electronically excited state dipole moments. For all the molecules investigated here the dipole moments in the excited state are higher than their ground state values.
    Matched MeSH terms: Ultraviolet Rays
  14. Fulltext The effects of UV treatment on the properties of sago and mung bean films
    Ummi-Shafiqah, M.S., Fazilah, A., Karim, A.A., Kaur, B., Yusup, Y.
    International Food Research Journal, 2012;19(1):265-270.
    MyJurnal
    Starch blend films made from sago and mung bean were prepared by casting with glycerol as the plasticizer and subsequently exposed to ultraviolet (UV) irradiation for 2 h. The films were characterized by thickness, moisture sorption isotherms, X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy. All films produced were colorless while incorporation of glycerol resulted in more flexible and manageable films. Moisture sorption isotherms for all films showed sigmoidal shape and the control films showed slightly higher curve than treated films. While for X-ray analysis, the control and treated films for all formulations showed similar pattern, however for treated films showed more crystalline character. UV radiation showed affect on X-ray diffraction and sorption isotherms; however the UV radiation did not affect the spectra pattern of FTIR.
    Matched MeSH terms: Ultraviolet Rays
  15. The effect of ultraviolet treatment on enzymatic activity and total phenolic content of minimally processed potato slices
    Teoh LS, Lasekan O, Adzahan NM, Hashim N
    J Food Sci Technol, 2016 Jul;53(7):3035-3042.
    PMID: 27765974
    In this work, potato slices were exposed to different doses of UV-C irradiation (i.e. 2.28, 6.84, 11.41, and 13.68 kJ m(-2)) with or without pretreatment [i.e. ascorbic acid and calcium chloride (AACCl) dip] and stored at 4 ± 1 °C. Changes in enzymatic activities of polyphenol oxidase (PPO), peroxidase (POD) and phenylalanine ammonia lyase (PAL), as well as total phenolic content (TPC) were investigated after 0, 3, 7 and 10 days of storage. Results showed that untreated and UV-C treated potato slices at 13.68 kJ m(-2) dosage level showed significantly higher PPO, POD and PAL activities. Conversely, untreated potato slices showed the lowest TPC during storage period. Potato slices subjected to AACCl dip plus UV-C at 6.84 kJ m(-2) produced lower PPO, POD and PAL activities, as well as maintained a high TPC during storage.
    Matched MeSH terms: Ultraviolet Rays
  16. Fulltext The effect of storage on the quality attributes of ultraviolet-irradiated and thermally pasteurised pineapple juices
    Chia, S. L., Rosnah, S., Noranizan, M. A., Wan Ramli, W. D.
    International Food Research Journal, 2012;19(3):1001-1010.
    MyJurnal
    The effect of storage time on the quality of ultraviolet-irradiated and thermally pasteurised pineapple juice was evaluated. The juices were irradiated with ultraviolet light (UV-C) at wavelength 254 nm (53.42 mJ/cm2, 4.918 s), thermally pasteurised at 800C for 10 minutes and stored at 40C for 13 weeks. There were significant changes in the total soluble solids, pH, titratable acidity and turbidity of UV-irradiated juice during storage, whereas for the same quality attributes of thermally pasteurised juice remained stable throughout the storage time. There were no significant changes in total phenolics for both treatments throughout the storage period. Other quality parameters (ascorbic acid, colour L, hue angle and chroma) were significantly affected by the storage time. Regarding the microbiological analysis, the total plate counts and yeast and mould counts of the UV-irradiated juice increased gradually throughout the 13 weeks of storage while these parameters remained unchanged in the thermally pasteurised juice with almost no microorganism growth. UV-irradiated pineapple juice preserved better quality attributes (TSS, pH, titratable acidity, ascorbic acid, turbidity, total phenolic, L (lightness), hue angle and chroma) than the thermal pasteurised juice during the storage time. Hence, UV irradiation has great potential as an alternative technology to thermal pasteurisation in producing products of high nutritive values.
    Matched MeSH terms: Ultraviolet Rays
  17. The effect of high UV radiation exposure environment on the novel PVC polymers
    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*
  18. The effect of combination enzymatic and advanced oxidation process treatments on the colour of pulp and paper mill effluent
    Karimi S, Abdulkhani A, Karimi A, Ghazali AH, Ahmadun FL
    Environ Technol, 2010 Apr 1;31(4):347-56.
    PMID: 20450108 DOI: 10.1080/09593330903473861
    The efficiency of advanced oxidation processes (AOPs), enzymatic treatment and combined enzymatic/AOP sequences for the colour remediation of soda and chemimechanical pulp and paper mill effluent was investigated. The results indicated that under all circumstances, the AOP using ultraviolet irradiation (photo-Fenton) was more efficient in the degradation of effluent components in comparison with the dark reaction. It was found that both versatile peroxidase (VP) from Bjerkandera adusta and laccase from Trametes versicolor, as pure enzymes, decolorize the deep brown effluent to a clear light-yellow solution. In addition, it was found that in the laccase treatment, the decolorization rates of both effluents were enhanced in the presence of 2, 2'-azinobis (3-ethylbenzthiazoline-6-sulfonate), while in the case of VP, Mn(+2) decreased the efficiency of the decolorization treatment. The concomitant use of enzymes and AOPs imposes a considerable effect on the colour remediation of effluent samples.
    Matched MeSH terms: Ultraviolet Rays
  19. Fulltext Synthesis of lignin based composites of TiO2 for potential application as radical scavengers in sunscreen formulation
    Ibrahim MNM, Iqbal A, Shen CC, Bhawani SA, Adam F
    BMC Chem, 2019 Dec;13(1):17.
    PMID: 31384766 DOI: 10.1186/s13065-019-0537-3
    Titanium dioxide (TiO2) is added in sunscreens due to its ability to absorb ultraviolet (UV) light. However, upon irradiation of UV light, reactive oxygen species particularly hydroxyl radical which can damage human skin will be generated. In this study, lignin/TiO2 composites were employed to quench the hydroxyl radicals generated by the TiO2. The lignin was extracted from oil palm empty fruit bunch (OPEFB) via kraft and soda pulping processes. The kraft lignin composite was labelled as KL/TiO2 whereas the soda lignin composite was labelled as SL/TiO2. The lignins and the composites were characterized by FTIR, UV spectroscopy, 13C NMR, SEM, EDX, and XRD. The relative hydroxyl radical production of composites and TiO2 were compared through photo-oxidation of coumarin to 7-hydroxycoumarin as a test medium. The effect of types and amounts of lignin used were studied. The KL/TiO2 composite showed the least radical production due to higher phenolic hydroxyl content of kraft lignin. The activity of the hydroxyl radicals will be quenched when it abstract hydrogen atoms from the phenolic hydroxyl groups.
    Matched MeSH terms: Ultraviolet Rays
  20. Fulltext Synthesis of Radiation Curable Palm Oil-Based Epoxy Acrylate: NMR and FTIR Spectroscopic Investigations
    Salih AM, Ahmad MB, Ibrahim NA, Dahlan KZ, Tajau R, Mahmood MH, et al.
    Molecules, 2015;20(8):14191-211.
    PMID: 26248072 DOI: 10.3390/molecules200814191
    Over the past few decades, there has been an increasing demand for bio-based polymers and resins in industrial applications, due to their potential lower cost and environmental impact compared with petroleum-based counterparts. The present research concerns the synthesis of epoxidized palm oil acrylate (EPOLA) from an epoxidized palm oil product (EPOP) as environmentally friendly material. EPOP was acrylated by acrylic acid via a ring opening reaction. The kinetics of the acrylation reaction were monitored throughout the reaction course and the acid value of the reaction mixture reached 10 mg KOH/g after 16 h, indicating the consumption of the acrylic acid. The obtained epoxy acrylate was investigated intensively by means of FTIR and NMR spectroscopy, and the results revealed that the ring opening reaction was completed successfully with an acrylation yield about 82%. The UV free radical polymerization of EPOLA was carried out using two types of photoinitiators. The radiation curing behavior was determined by following the conversion of the acrylate groups. The cross-linking density and the hardness of the cured EPOLA films were measured to evaluate the effect of the photoinitiator on the solid film characteristics, besides, the thermal and mechanical properties were also evaluated.
    Matched MeSH terms: Ultraviolet Rays*
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