Different morphologies of Ag2Te nanostructures were synthesized using TeCl4 as a new precursor and hydrazine hydrate as reducing agent by a hydrothermal method. Various parameters that affect on morphology and purity of nanostructures were optimized. According to our experiments the best time and temperature for preparation of this nanostructure are 12 h and 120 °C. The photo-catalytic behaviour of nanostructures in presence of UV-visible light for degradation of methyl orange was investigated. Results show that the presence of UV light is necessary for an efficient degradation of dye in aqueous solution. On the other hand, as observations propose the Ag2Te reveal a strong photoluminescence peak at room temperature that could be attributed to high level transition in the semiconductor. Nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) techniques and UV-visible scanning spectrometer (UV-Vis).
The hybrid electrochemical system of photocatalytic fuel cell - peroxi-coagulation (PFC-PC) is a combined technology of advanced oxidation process (AOP) which involve the hydroxyl radical formation for simultaneous degradation of organic pollutant and electricity generation. The p-nitrosodimethylaniline (RNO) spin trapping technique was applied by analyzing the RNO bleaching performance to detect the OH at the PFC and PC reactors. The presence of UV light showed higher RNO bleaching rate at the PFC reactor (11.7%) with maximum power density (Pmax = 3.14 mW cm-2). Results revealed that the optimum of maximum power density was observed at iron plate size of 30 cm2. UV light became a limiting factor in the PFC system as a power source in the PFC-PC system. Meanwhile, iron plate plays an important role to supply the soluble Fe2+ ions by oxidation process and become a suitable catalyst for in-situ production of H2O2 and OH through the PC process to degrade the organic molecules.
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.
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.
A new Schiff base containing 1,2,4-triazole ring system (L) was synthesized and confirmed by 1HNMR, FTIR spectroscopy. The chemical modification of PVC with a new Schiff base (L) was synthesized to produce a homogenous blend (PVC-L). A homogenous blend (PVC-L) was added to copper chloride to produce PVC-L-Cu (II). The PVC films had been irradiated with ultraviolet light for a long period and confirmed by FTIR spectroscopy and weight loss; the surface morphology was inspected by scanning electron microscopy.
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.
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.
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.
Nanotechnology is one of the most interesting areas of research due to its flexibility to improve or form new products from nanoparticles (NPs), and as a fast, greener, more eco-friendly and sustainable solution to technological and environmental challenges. Among metal oxides of photocatalytic performance, the use of titania (TiO2) as photocatalyst is most popular due to its unique optical and electronic properties. Despite the wide utilization, the synthesis of TiO2 NPs bears many disadvantages: it utilizes various less environmental-friendly chemicals, high cost, requires high pressure and energy, and potentially hazardous physical and chemical methods. Hence, the development of green synthesis approach with eco-friendly natural products can be used to overcome these adverse effects. In this work, TiO2 NPs have been prepared by using Deinbollia pinnata leaves extracts, obtained by different solvents (n-hexane, ethyl acetate, and ethanol) with different polarities. The extracts acted as the reducing agent, while titanium isopropoxide as the precursor and water as the solvent. X-ray diffraction (XRD) pattern confirmed the synthesized TiO2 consist of anatase phase in high purity, with average crystallite size in the range of 19-21 nm. Characterization by using field emission scanning electron microscopy (FESEM) showed the TiO2 NPs possess a uniform semi-spherical shape in the size range of 33-48 nm. The energy dispersive X-ray (EDX) spectra of green TiO2 NPs showed two peaks for the main elements of Ti (61 Wt.%) and O (35 Wt.%). The band-gap energy of 3.2 eV was determined using UV-Vis spectroscopy. From the nitrogen sorption analysis, type V isotherm of the material was obtained, with BET surface area of 31.77 m2/g. The photocatalytic activity of synthesized TiO2 was evaluated for photodegradation of methyl orange (MO) under UV light irradiation. Based on the results, it is shown that TiO2 NPs synthesized with D. pinnata leaves extracted using ethyl acetate showed the most effective photodegradation performance, achieving 98.7% of MO conversion within 150 min. It can be concluded that the use of plant extracts in synthesis with TiO2 managed to produce highly crystalline anatase TiO2 with superior photocatalytic activity in the photodegradation of organic dye.
Global warming and ozone depletion, and the resulting increase of ultraviolet radiation (UVR), have far-reaching impacts on biota, especially affecting the algae that form the basis of the food webs in aquatic ecosystems. The aim of the present study was to investigate the interactive effects of temperature and UVR by comparing the photosynthetic responses of similar taxa of Chlorella from Antarctic (Chlorella UMACC 237), temperate (Chlorella vulgaris UMACC 248) and tropical (Chlorella vulgaris UMACC 001) environments. The cultures were exposed to three different treatments: photosynthetically active radiation (PAR; 400-700 nm), PAR plus ultraviolet-A (320-400 nm) radiation (PAR + UV-A) and PAR plus UV-A and ultraviolet-B (280-320 nm) radiation (PAR + UV-A + UV-B) for one hour in incubators set at different temperatures. The Antarctic Chlorella was exposed to 4, 14 and 20°C. The temperate Chlorella was exposed to 11, 18 and 25°C while the tropical Chlorella was exposed to 24, 28 and 30°C. A pulse-amplitude modulated (PAM) fluorometer was used to assess the photosynthetic response of microalgae. Parameters such as the photoadaptive index (Ek) and light harvesting efficiency (α) were determined from rapid light curves. The damage (k) and repair (r) rates were calculated from the decrease in ΦPSIIeff over time during exposure response curves where cells were exposed to the various combinations of PAR and UVR, and fitting the data to the Kok model. The results showed that UV-A caused much lower inhibition than UV-B in photosynthesis in all Chlorella isolates. The three isolates of Chlorella from different regions showed different trends in their photosynthesis responses under the combined effects of UVR (PAR + UV-A + UV-B) and temperature. In accordance with the noted strain-specific characteristics, we can conclude that the repair (r) mechanisms at higher temperatures were not sufficient to overcome damage caused by UVR in the Antarctic Chlorella strain, suggesting negative effects of global climate change on microalgae inhabiting (circum-) polar regions. For temperate and tropical strains of Chlorella, damage from UVR was independent of temperature but the repair constant increased with increasing temperature, implying an improved ability of these strains to recover from UVR stress under global warming.
In the environment, sunlight or ultraviolet (UV) radiation is considered to be the primary cause of plastic aging, leading to their fragmentation into particles, including micro(nano)plastics (MNPs). Photoaged MNPs possess diverse interactive properties and ecotoxicological implications substantially different from those of pristine plastic particles. This review aims to highlight the mechanisms and implications of UV-induced photoaging of MNPs, with an emphasis on various UV sources and their interactions with co-occurring organic and inorganic chemicals, as well as the associated ecological and health impacts and factors affecting those interactions. Compared to UV-B, UV-A and UV-C were more widely used in laboratory studies for MNP degradation. Photoaged MNPs act as vectors for the transportation of organic pollutants, organic matter, and inorganic chemicals in the environment. Literature showed that photoaged MNPs exhibit a higher sorption capacity for PPCPs, PAHs, PBDEs, pesticides, humic acid, fulvic acid, heavy metals, and metallic nanoparticles than pristine MNPs, potentially causing significant changes in associated ecological and health impacts. Combined exposure to photoaged MNPs and organic and inorganic pollutants significantly altered mortality rate, decreased growth rate, histological alterations, neurological impairments, reproductive toxicity, induced oxidative stress, thyroid disruption, hepatotoxicity, and genotoxicity in vivo, both in aquatic and terrestrial organisms. Limited studies were reported in vitro and found decreased cellular growth and survival, induced oxidative stress, and compromised the permeability and integrity of the cell membrane. In addition, several environmental factors (temperature, organic matter, ionic strength, time, and pH), MNP properties (polymer types, sizes, surface area, shapes, colour, and concentration), and chemical properties (pollutant type, concentration, and physiochemical properties) can influence the photoaging of MNPs and associated impacts. Lastly, the research gaps and prospects of MNP photoaging and associated implications were also summarized. Future research should focus on the photoaging of MNPs under environmentally relevant conditions, exploiting the polydisperse characteristics of environmental plastics, to make this process more realistic for mitigating plastic pollution.
A new sample preparation method, ion-pair vortex assisted liquid-liquid microextraction (VALLME-BE), for the determination of a highly polar anti-diabetic drug (metformin) in plasma sample was developed. The VALLME-BE was performed by diluting the plasma in borate buffer and extracted to 150µL 1-octanol containing 0.2M di-(2-ethylhexyl)phosphoric acid as intermediate phase. The drug was next back-extracted into 20µL of 0.075M HCl solution. The effects of pH, ion-pair concentration, type of organic solvent, volume of extraction phases, ionic strength, vortexing and centrifugation times on the extraction efficiency were investigated. The optimum conditions were at pH 9.3, 60s vortexing and 2min centrifugation. The microextract, contained metformin and buformin (internal standard), was directly injected into a HPLC unit using C1 column (250mm×4.6mm×10µm) and detected at 235nm. The method was validated and calibration curve was linear with r2>0.99 over the range of 20-2000µgL-1. The limits of detection and quantitation were 1.4 and 4.1µgL-1, respectively. The accuracy was within 94.8-108% of the nominal concentration. The relative standard deviation for inter- and intra-day precision was less than 10.8%. The method was conveniently applied for the determination of metformin in plasma samples.
INTRODUCTION: Excessive ultraviolet light (UV) can cause premature skin aging and potentially skin cancer. Currently there is a lack of awareness among health care professionals and the public on sun protection. The objectives of this study were to determine knowledge on sunscreen and skin cancer among health care professionals, to evaluate the knowledge, attitude, practice and perception of doctors and pharmacists toward the usage of sunscreen as protection against UV radiation.
MATERIALS AND METHODS: This is a cross-sectional study conducted among doctors and pharmacists in Hospital Sultanah Nora Ismail, Batu Pahat, Johor, Malaysia. Questionnaires were used in this study.
RESULTS: A total of 384 participants completed the questionnaires. The participants consisted of 323 doctors (84.1%) and 61 pharmacists (15.9%). The age group of the participants ranged between 25 till 55 years old. Ninety doctors (27.9%) and thirty-one pharmacists (51.0%) reported used sunscreen daily (p<0.001). This finding showed that there was a deficit in the practice of sun protection. Pharmacists scored a higher knowledge score of median 12 (IQR=3.0) while the doctors scored 11 (IQR=2.0). This study showed a significant association between ethnicity and skin cancer knowledge (p<0.05).
CONCLUSION: This study demonstrated a lack of knowledge of sunscreen and skin cancer prevention among health care practitioners. This finding supports better medical education program on this topic.
Protein oxidation of beef patties stored in high oxygen modified atmosphere packaging for 9 days was investigated. Meat was either stored in the dark, under light, or in the dark with addition of FeCl2/H2O2/myoglobin (forced oxidation). SDS-PAGE analysis showed high degree of protein polymerization for meat exposed to light, compared to the other samples. Light exposure induced reducible (disulfide) and non-reducible cross-links, while mainly disulfides were formed in meat stored in the dark. Light exposure was responsible for 58% loss of free thiols (Cys residues). No significant loss of other amino acid residues was observed and none of the most common oxidation products of tryptophan, tyrosine, and phenylalanine were detected. Intrinsic fluorescence measurements of tryptophan showed 27% loss in samples exposed to light, which was ascribed to loss of protein solubility via protein polymerization rather than tryptophan oxidation. Protein carbonyls were mainly detected in forced oxidized samples at Day 0.
The objective of this study was to determine the efficiency of UV blocking monomers in contact lenses in providing eye protection from UV radiation. The spectral transmission of 8 contact lenses (7 soft contact lenses: Precision UV, Acuvue 2, Surevue, Omega, Encore UV, Durasoft 3 and Lunelle UV and 1 rigid gas permeable contact lens: Boston 7) was evaluated by using a dual beam spectrophotometer. Durasoft 3, a non UV absorbent contact lens was used as the control. The results showed that Precision UV contact lens absorbed UV light up to wavelength of 380 nm, whereas Acuvue 2 and Surevue absorbed up to 360 nm only. Omega, Encore UV and Lunelle UV lenses absorbed UV light up to 335 nm with spectral transmission of Lunelle UV being the highest among all soft contact lenses tested, which was 17%. Boston 7 could absorb UV light up to 385 nm, but the amount of UV light transmitted was higher than soft lenses, which was 30%. Durasoft 3 only blocked UV light at 200-245 nm. Precision UV lens had better UV blocker characteristics than the other contact lenses tested. UV blocking soft contact lenses could be an alternative for spectacles in protecting internal ocular structures from UV radiation.
Five luminescent polymorphic aggregates of trinuclear Cu(i)-pyrazolate, namely [anti-Cu3L3]2 (1), [syn-Cu3L3·C2H5OH]2 (2), [anti-Cu3L3·C2H5OH]n (3), [anti-Cu3L3·0.5C7H8]n (4) and [syn-Cu3L3·C8H10]n (5) (HL = 4-(pyridin-4-ylthio)-3,5-dimethyl-1H-pyrazole), were reported. The trimeric Cu3L3 fragments present syn- and anti-conformations dependent on the dangled direction of 4-pyridyl groups on the two sides of the Cu3Pz3 plane (Pz = pyrazolate). Intertrimeric NPyCu weak coordination bonds associate these Cu3L3 fragments together to form dimeric or polymeric structures, which are further stabilized by crystallized solvent molecules or intertrimeric CuCu interactions. The solvated complexes (3-5) may be transformed into the unsolvated complex 1 by evacuation of the crystallized solvents upon heating. All these complexes emit from green to yellow under UV irradiation, which originated from the triplet excited states of metal to ligand charge transfer (3MLCT) mixed with intertrimeric CuCu interactions. This work provides a novel kind of supramolecular aggregate based on Cu3Pz3 beyond the classical π-acidbase adducts and metallophilicity-dependent dimers/oligomers.
The sol-gel/ultrasonically rout produced the novel MnS2-SiO2 nano-hetero-photocatalysts with the various ratio of MnS2. Prepared nano-catalyst were investigated in the photo-degradation of methylene blue under UV light illumination. Structural and optical attributes of as-prepared nano-catalysts were evaluated by X-ray diffraction and photoelectron spectroscopy. The morphological were studied by scanning electron microscopy-EDS, and dynamic light scattering. The diffuse reflectance spectroscopy was applied to examine the band gap energy. The Eg values of SiO2, MnS2-SiO2-0, MnS2-SiO2-1, and MnS2-SiO2-2 nanocomposites are 6.51, 3.85, 3.17, and 2.67 eV, respectively. The particle size of the SiO2 and MnS2-SiO2-1 nanocomposites were 100.0, and 65.0 nm, respectively. The crystallite size values of MnS2-SiO2-1 were 52.21 nm, and 2.9 eV, respectively. MnS2-SiO2 nano-photocatalyst was recognized as the optimum sample by degrading 96.1% of methylene blue from water. Moreover, the influence of pH of the solution, and contact time as decisive factors on the photo-degradation activity were investigated in this project. The optimum data for pH and time were found 9 and 60 min, respectively. The photo-degradation capacity of MnS2-SiO2-2 is improved (96.1%) due to the low band gap was found from UV-vis DRS. The antimicrobial data of MnS2-SiO2 were studied and demonstrated that the MnS2-SiO2 has fungicidal and bactericidal attributes.
UV curable coating formulation comprises urethane acrylate resin and nanosilica as filler were synthesized to develop UV curable inorganic organic hybrid composite (PUA). The surface of the nanosilica was chemically modified to improve its chemical interaction within the urethane acrylate matrix. The modification had been undertaken by applying vinyltrymetoxysilane (VTMOS) that acted as a coupling agent to produce organophilic silica shell (SIMA). The shell is linked to the silica via reaction with the surface silanol group of the silica. The disappearance of metoxy groups in VTMOS was demonstrated by FTIR spectrum. The percentage of silica particles in UV curable hybrid formulation were varied on 5%, 10%, 15%, 20% and 250% respectively. In this work, the formulation was applied on medium density fiber board (11/IDF) substrate and subsequent has been irradiated under UV light. Then, the coated MDF were characterized by several testing equipments (TGA, DSC, scratch tester, instron, SEM). From the result, we found that the addition of silica nanoparticles exhibit significant improvement in coating film properties as compared to film without silica nanoparticle includes significant improvement in its modulus and scratch resistance. This make them as promising coating candidate for MDF product. On the other hand, we also found that an increase of silica particle up to 25 wt%, the viscosity has increased rapidly indicates that it is not suitable for acrylate coating formulation due to disappearance of desired effect known as tixotrophy.
Effluent discharges from industry and domestic waste containing unknown inorganic pollutants. In this work, different mechanisms of heavy metal ions removal using ZnO particles were studied. ZnO particles were synthesized using solid precipitation technique. The morphology of ZnO particles was rod-like shape. The average length and diameter of ZnO particle were 497.34 ± 15.55 and 75.78 ± 10.39nm, respectively. These particles removed effectively heavy metal ions such as Cu(II), Ag(I) and Pb(II) ions with efficiency >85% under exposure of 1 hour of UV light. However, poor removal efficiency, i.e. <15% was observed for Cr(VI), Mn(II), Cd(II) and Ni(II) ions. The removal of these heavy metal ions was in the forms of metals or metal oxide via reduction/oxidation or adsorption mechanism.
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.