Displaying publications 161 - 180 of 296 in total

Abstract:
Sort:
  1. Glutathione system in young spontaneously hypertensive rats
    Lee SK, Arunkumar S, Sirajudeen KN, Singh HJ
    J Physiol Biochem, 2010 Dec;66(4):321-7.
    PMID: 20680541 DOI: 10.1007/s13105-010-0038-2
    Glutathione (GSH) forms a part of the antioxidant system that plays a vital role in preventing oxidative stress, and an imbalance in the oxidant/antioxidant system has been linked to the pathogenesis of hypertension. The aim of this study was to investigate the status of the GSH system in the kidney of spontaneously hypertensive rats (SHR). Components of the GSH system, including glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST), and total GSH content, were measured in the kidneys of 4, 6, 8, 12, and 16 weeks old SHR and Wistar-Kyoto (WKY) rats. Systolic blood pressure of SHR was significantly higher from the age of 6 weeks onwards compared with age-matched WKY rats. GPx activity in the SHR was significantly lower from the age of 8 weeks onwards when compared to that in age-matched WKY rats. No significant differences were evident in the GPx-1 protein abundance, and its relative mRNA levels, GR, GST activity, and total GSH content between SHR and age-matched WKY rats. The lower GPx activity suggests of an impairment of the GSH system in the SHR, which might be due to an abnormality in its protein rather than non-availability of a cofactor. Its role in the development of hypertension in SHR however remains unclear.
    Matched MeSH terms: Hydrogen Peroxide/chemistry
  2. Fulltext Giant Cell Tumour Around Knee Managed by Curettage and Zoledronic Acid with Structural Support by Fibula Cortical Struts
    Singaravadivelu V, Kavinkumar V
    Malays Orthop J, 2020 Nov;14(3):42-49.
    PMID: 33403061 DOI: 10.5704/MOJ.2011.008
    Introduction: Giant cell tumour (GCT) of the bone is a benign tumour with a high tendency to recur after surgery. This study aimed to analyse prospectively the rate of local recurrence following management of giant cell tumours by curettage, using intravenous zoledronic acid as an adjuvant, and fibular struts to support the empty cavity after curettage.

    Materials and Methods: This study was carried out in ten cases of biopsy-proven GCTs: five males and five females, in the age group between 18 and 39 years. All patients were given three doses of zoledronic acid, one pre-operative and two post-operative. Extended curettage was done three weeks after the pre-operative dose of zoledronate. The cavity was left empty in all the cases. Fibular struts were used to support the cavity from collapse. Patients were followed-up for post-operative local recurrence. The functional status of the patients was assessed during each visit using the Musculoskeletal Tumour Society (MSTS) score.

    Results: There were no recurrences at a follow-up of two years. All patients had a stable knee and were able to bear weight fully. The average knee flexion was 75º. The average MSTS score of the study was 92%.

    Conclusion: Extended curettage using hydrogen peroxide, systemic zoledronic acid adjuvant and leaving the cavity empty without using cancellous bone graft did not lead to a recurrence of GCT. Non-vascularised fibular strut provided adequate support while the cavity left empty after curettage did not collapse and there was good knee function.

    Matched MeSH terms: Hydrogen Peroxide
  3. Fulltext Germinated Brown Rice Alters Aβ(1-42) Aggregation and Modulates Alzheimer's Disease-Related Genes in Differentiated Human SH-SY5Y Cells
    Azmi NH, Ismail M, Ismail N, Imam MU, Alitheen NB, Abdullah MA
    Evid Based Complement Alternat Med, 2015;2015:153684.
    PMID: 26858770 DOI: 10.1155/2015/153684
    The pathogenesis of Alzheimer's disease involves complex etiological factors, of which the deposition of beta-amyloid (Aβ) protein and oxidative stress have been strongly implicated. We explored the effects of H2O2, which is a precursor for highly reactive hydroxyl radicals, on neurotoxicity and genes related to AD on neuronal cells. Candidate bioactive compounds responsible for the effects were quantified using HPLC-DAD. Additionally, the effects of germinated brown rice (GBR) on the morphology of Aβ(1-42) were assessed by Transmission Electron Microscopy and its regulatory effects on gene expressions were explored. The results showed that GBR extract had several phenolic compounds and γ-oryzanol and altered the structure of Aβ(1-42) suggesting an antiamyloidogenic effect. GBR was also able to attenuate the oxidative effects of H2O2 as implied by reduced LDH release and intracellular ROS generation. Furthermore, gene expression analyses showed that the neuroprotective effects of GBR were partly mediated through transcriptional regulation of multiple genes including Presenilins, APP, BACE1, BACE2, ADAM10, Neprilysin, and LRP1. Our findings showed that GBR exhibited neuroprotective properties via transcriptional regulation of APP metabolism with potential impact on Aβ aggregation. These findings can have important implications for the management of neurodegenerative diseases like AD and are worth exploring further.
    Matched MeSH terms: Hydrogen Peroxide
  4. Fulltext Genome-wide CRISPR screen identifies LGALS2 as an oxidative stress-responsive gene with an inhibitory function on colon tumor growth
    Li H, Zhao L, Lau YS, Zhang C, Han R
    Oncogene, 2021 01;40(1):177-188.
    PMID: 33110234 DOI: 10.1038/s41388-020-01523-5
    Colorectal cancer is the third leading cause of cancer-related deaths in the United States and the third most common cancer in men and women. Around 20% colon cancer cases are closely linked with colitis. Both environmental and genetic factors are thought to contribute to colon inflammation and tumor development. However, the genetic factors regulating colitis and colon tumorigenesis remain elusive. Since reactive oxygen species (ROS) is vitally involved in tissue inflammation and tumorigenesis, here we employed a genome-wide CRISPR knockout screening approach to systemically identify the genetic factors involved in the regulation of oxidative stress. Next generation sequencing (NGS) showed that over 600 gRNAs including the ones targeting LGALS2 were highly enriched in cells survived after sublethal H2O2 challenge. LGALS2 encodes the glycan-binding protein Galectin 2 (Gal2), which is predominantly expressed in the gastrointestinal tract and downregulated in human colon tumors. To examine the role of Gal2 in colitis, we employed the dextran sodium sulfate (DSS)-induced acute colitis model in mice with (WT) or without Lgals2 (Gal2-KO) and showed that Gal2 deficiency ameliorated DSS-induced colitis. We further demonstrated that Gal2-KO mice developed significantly larger tumors than WT mice using Azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced colorectal cancer model. We found that STAT3 phosphorylation was significantly increased in Gal2-deficient tumors as compared to those in WT mice. Gal2 overexpression decreased the proliferation of human colon tumor epithelial cells and blunted H2O2-induced STAT3 phosphorylation. Overall, our results demonstrate that Gal2 plays a suppressive role in colon tumor growth and highlights the therapeutic potential of Gal2 in colon cancer.
    Matched MeSH terms: Hydrogen Peroxide/adverse effects
  5. Fulltext Gene Expression Analysis Reveals the Concurrent Activation of Proapoptotic and Antioxidant-Defensive Mechanisms in Flavokawain B-Treated Cervical Cancer HeLa Cells
    Yeap SK, Abu N, Akthar N, Ho WY, Ky H, Tan SW, et al.
    Integr Cancer Ther, 2017 09;16(3):373-384.
    PMID: 27458249 DOI: 10.1177/1534735416660383
    Flavokawain B (FKB) is known to possess promising anticancer abilities. This is demonstrated in various cancer cell lines including HeLa cells. Cervical cancer is among the most widely diagnosed cancer among women today. Though FKB has been shown to be effective in treating cancer cells, the exact molecular mechanism is still unknown. This study is aimed at understanding the effects of FKB on HeLa cells using a microarray-based mRNA expression profiling and proteome profiling of stress-related proteins. The results of this study suggest that FKB induced cell death through p21-mediated cell cycle arrest and activation of p38. However, concurrent activation of antioxidant-related pathways and iron sequestration pathway followed by activation of ER-resident stress proteins clearly indicate that FKB failed to induce apoptosis in HeLa cells via oxidative stress. This effect implies that the protection of HeLa cells by FKB from H2O2-induced cell death is via neutralization of reactive oxygen species.
    Matched MeSH terms: Hydrogen Peroxide/pharmacology
  6. Gelam and Nenas honeys inhibit proliferation of HT 29 colon cancer cells by inducing DNA damage and apoptosis while suppressing inflammation
    Wen CT, Hussein SZ, Abdullah S, Karim NA, Makpol S, Mohd Yusof YA
    Asian Pac J Cancer Prev, 2012;13(4):1605-10.
    PMID: 22799375
    Gelam and Nenas monofloral honeys were investigated in this study for their chemopreventive effects against HT 29 colon cancer cells. MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H- tetrazolim) assays showed more effective inhibition of colon cancer cells proliferation by Gelam honey with IC₅₀ values of 39.0 mg/ml and 85.5 mg/ml respectively after 24 hours of treatment. Alkali comet assays revealed both honeys increased DNA damage significantly in a dose dependent manner. In addition, annexin V-FITC/PI flow cytometry demonstrated that at IC₅₀ concentrations and above, both Gelam and Nenas honeys induced apoptosis significantlyat values higher than for necrosis (p<0.05). Measurement of prostaglandin E₂ (PGE₂) confirmed that Gelam and Nenas honeys reduced its production in H₂O₂ inflammation-induced colon cancer cells. In conclusion, our study indicated and confirmed that both Gelam and Nenas honeys are capable of suppressing the growth of HT 29 colon cancer cells by inducing apoptosis and suppressing inflammation.
    Matched MeSH terms: Hydrogen Peroxide
  7. Garlic flavonoids alleviate H2 O2 induced oxidative damage in L02 cells and induced apoptosis in HepG2 cells by Bcl-2/Caspase pathway
    Gao X, Yanan J, Santhanam RK, Wang Y, Lu Y, Zhang M, et al.
    J Food Sci, 2021 Feb;86(2):366-375.
    PMID: 33448034 DOI: 10.1111/1750-3841.15599
    Liver damage is a common liver disorder, which could induce liver cancer. Oral antioxidant is one of the effective treatments to prevent and alleviate liver damage. In this study, three flavonoids namely myricetin, isoquercitrin, and isorhamnetin were isolated and identified from Laba garlic. The isolated compounds were investigated on the protective effects against H2 O2 -induced oxidative damages in hepatic L02 cells and apoptosis inducing mechanism in hepatic cancer cells HepG2 by using MTT assay, flow cytometry and western blotting analysis. Myricetin, isoquercitrin, and isorhamnetin showed proliferation inhibition on HepG2 cells with IC50 value of 44.32 ± 0.213 µM, 49.68 ± 0.192 µM, and 54.32 ± 0.176 µM, respectively. While they showed low toxicity on normal cell lines L02. They could significantly alleviate the oxidative damage towards L02 cells (P < 0.05), via inhibiting the morphological changes in mitochondria and upholding the integrity of mitochondrial structure and function. The fluorescence intensity of L02 cells pre-treated with myricetin, isoquercitrin, and isorhamnetin (100 µM) was 89.23 ± 1.26%, 89.35 ± 1.43% and 88.97 ± 0.79%, respectively. Moreover, the flavonoids could induce apoptosis in HepG2 cells via Bcl-2/Caspase pathways, where it could up-regulate the expression of Bax and down-regulate the expression of Bcl-2, Bcl-xL, pro-Caspase-3, and pro-Caspase-9 proteins in a dose dependent manner. Overall, the results suggested that the flavonoids from Laba garlic might be a promising candidate for the treatment of various liver disorders. PRACTICAL APPLICATION: Flavonoids from Laba garlic showed selective toxicity towards HepG2 cells in comparison to L02 cells via regulating Bcl-2/caspase pathway. Additionally, the isolated flavonoids expressively barred the oxidative damage induced by H2 O2 in L02 cells. These results suggested that the flavonoids from laba garlic could be a promising agent towards the development of functional foods.
    Matched MeSH terms: Hydrogen Peroxide/pharmacology*
  8. GR15 peptide of S-adenosylmethionine synthase (SAMe) from Arthrospira platensis demonstrated antioxidant mechanism against H2O2 induced oxidative stress in in-vitro MDCK cells and in-vivo zebrafish larvae model
    Velayutham M, Guru A, Arasu MV, Al-Dhabi NA, Choi KC, Elumalai P, et al.
    J Biotechnol, 2021 Dec 10;342:79-91.
    PMID: 34751134 DOI: 10.1016/j.jbiotec.2021.10.010
    GR15 is a short molecule or peptide composed of aliphatic amino acids and possesses to have antioxidant properties. The GR15, 1GGGAFSGKDPTKVDR15 was identified from the protein S-adenosylmethionine synthase (SAMe) expressed during the sulfur departed state of Arthrospira platensis (spirulina or cyanobacteria). The in-silico assessment and the structural features of GR15 showed its antioxidant potency. Real-time PCR analysis found the up-regulation of ApSAMe expression on day 15 against oxidative stress due to 10 mM H2O2 treatment in A. platensis (Ap). The antioxidant activity of GR15 was accessed by the cell-free antioxidant assays such as ABTS, SARS, HRAS and NO; the results showed dose-dependent antioxidant activity. The toxicity assay was performed in both in vitro and in vivo models, in which peptide does not exhibit any toxicity in MDCK cell and zebrafish embryos. The intercellular ROS reduction potential of GR15 peptide was also investigated in both in vitro and in vivo models including LDH assay, antioxidant enzymes (SOD and CAT), and fluorescent staining assay (DCFDA, Hochest and Acridine orange sting) was performed; the results showed that the GR15 peptide was effectively reduced the ROS level. Further, RT-PCR demonstrated that GR15 enhanced the antioxidant property and also up-regulated the antioxidant gene, thus reduced the ROS level in both in vitro and in vivo models. Based on the results obtained from this study, we propose that GR15 has the potential antioxidant ability; hence further research can be directed towards the therapeutic product or drug development against disease caused by oxidative stress.
    Matched MeSH terms: Hydrogen Peroxide/toxicity
  9. GAPDH as housekeeping gene for human skin fibroblast senescent model
    Zainuddin A, Makpol S, Chua KH, Abdul Rahim N, Yusof YA, Ngah WZ
    Med J Malaysia, 2008 Jul;63 Suppl A:73-4.
    PMID: 19024990
    Validation of housekeeping gene is important for accurate quantitation of RNA in real time RT-PCR technique. The purpose of this study was to determine the validity of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as a housekeeping gene for quantitative real time RT-PCR assessment in human skin fibroblast senescent model. The cells were divided into different treatment groups; young (passage 4), senescent (passage 30), treatment with H2O2 and treatment with A-tocotrienol prior to H2O2 treatment. Our results showed that the expression level of GAPDH was constant with different treatment groups. Therefore, we concluded that GAPDH was suitable to be used as housekeeping gene in human skin fibroblast senescent model.
    Matched MeSH terms: Hydrogen Peroxide
  10. Functional Role of Tyr12 in the Catalytic Activity of Novel Zeta-like Glutathione S-transferase from Acidovorax sp. KKS102
    Shehu D, Alias Z
    Protein J, 2018 06;37(3):261-269.
    PMID: 29779193 DOI: 10.1007/s10930-018-9774-x
    Glutathione S-transferases (GSTs) are a family of enzymes that function in the detoxification of variety of electrophilic substrates. In the present work, we report a novel zeta-like GST (designated as KKSG9) from the biphenyl/polychlorobiphenyl degrading organism Acidovorax sp. KKS102. KKSG9 possessed low sequence similarity but similar biochemical properties to zeta class GSTs. Functional analysis showed that the enzyme exhibits wider substrate specificity compared to most zeta class GSTs by reacting with 1-chloro-2,4-dinitrobenzene (CDNB), p-nitrobenzyl chloride (NBC), ethacrynic acid (EA), hydrogen peroxide, and cumene hydroperoxide. The enzyme also displayed dehalogenation function against dichloroacetate, permethrin, and dieldrin. The functional role of Tyr12 was also investigated by site-directed mutagenesis. The mutant (Y12C) displayed low catalytic activity and dehalogenation function against all the substrates when compared with the wild type. Kinetic analysis using NBC and GSH as substrates showed that the mutant (Y12C) displayed a higher affinity for NBC when compared with the wild type, however, no significant change in GSH affinity was observed. These findings suggest that the presence of tyrosine residue in the motif might represent an evolutionary trend toward improving the catalytic activity of the enzyme. The enzyme as well could be useful in the bioremediation of various types of organochlorine pollutants.
    Matched MeSH terms: Hydrogen Peroxide
  11. Formation of grassy TiO2 nanotube thin film by anodisation in peroxide electrolyte for Cr(VI) removal under ultraviolet radiation
    Taib MAA, Alias N, Jaafar M, Razak KA, Tan WK, Shahbudin IP, et al.
    Nanotechnology, 2020 Oct 23;31(43):435605.
    PMID: 32640434 DOI: 10.1088/1361-6528/aba3d8
    Arrays of TiO2 nanotubes (TiO2 NTs) with grassy surfaces were observed on titanium foil anodised at 60 V in fluorinated ethylene glycol (EG) with added hydrogen peroxide (H2O2). The grassy surface was generated by the chemical etching and dissolution of the surface of the TiO2 NTs walls, which was accelerated by the temperature increase on the addition of H2O2 . Upon annealing at 600 °C, the grassy part of the TiO2 NTs was found to consist of mostly anatase TiO2 whereas the bottom part of the anodic oxide comprised a mixture of anatase and rutile TiO2. The TiO2 NTs were then used to reduce hexavalent chromium (Cr(VI)) under ultraviolet radiation. They exhibited a rather efficient photocatalytic effect, with 100% removal of Cr(VI) after 30 min of irradiation. The fast removal of Cr(VI) was due to the anatase dominance at the grassy part of the TiO2 NTs as well as the higher surface area the structure may have. This work provides a novel insight into the photocatalytic reduction of Cr(VI) on grassy anatase TiO2 NTs.
    Matched MeSH terms: Hydrogen Peroxide
  12. Flavonoids of Piper sarmentosum and its cytoprotective effects against oxidative stress
    Ugusman A, Zakaria Z, Hui CK, Nordin NA, Mahdy ZA
    EXCLI J, 2012;11:705-714.
    PMID: 27847456
    Abnormalities in endothelial cell structure and function may lead to diseases such as thrombosis and atherosclerosis. Oxidative stress plays an important role in the pathogenesis of various cardiovascular diseases including atherosclerosis. Previous studies have shown a relationship between a diet rich in flavonoid and a reduced incidence of cardiovascular diseases. Piper sarmentosum (PS) is a plant with high flavonoid content and it possesses antioxidant and anti-atherosclerotic activities. Therefore this study aimed to investigate the flavonoids present in aqueous extract of PS (AEPS) and its cytoprotective effects in oxidative stress-induced human umbilical vein endothelial cells (HUVEC). AEPS contained high total phenolic content (91.02 ± 0.02 mg QE/g DM) and total flavonoid content (48.57 ± 0.03 mg GAE/g DM). Screening using high performance liquid chromatography (HPLC) technique showed the presence of rutin and vitexin as the main flavonoids in AEPS. HUVEC were exposed to 180 µM H2O2 and treated with various concentrations of rutin or vitexin (10 to 400 µM) for 24 hours. Both rutin and vitexin at the concentration of 150-400 µM significantly increased the viability of H2O2-induced HUVEC as denoted by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Therefore rutin and vitexin as the main flavonoids present in PS may be involved in the protective effects of PS against oxidative stress.
    Matched MeSH terms: Hydrogen Peroxide
  13. Fish pond water treatment using ultrasonic cavitation and advanced oxidation processes
    Tan WK, Cheah SC, Parthasarathy S, Rajesh RP, Pang CH, Manickam S
    Chemosphere, 2021 Jul;274:129702.
    PMID: 33529956 DOI: 10.1016/j.chemosphere.2021.129702
    This investigation explores the efficacy of employing ultrasonic cavitation and coupling it with advanced oxidation processes (hydrogen peroxide and Fenton's reagent) for reducing the levels of total ammonia nitrogen in fish pond water containing Tilapia fishes. Ultrasonic cavitation is a phenomenon where the formation, growth and collapse of vaporous bubbles occur in a liquid medium producing highly reactive free radicals. Ultrasonic probe system (20 kHz with 750 W and 1000 W) was used to induce cavitation. Besides, to intensify the process, ultrasonic cavitation was coupled with hydrogen peroxide and Fenton's reagent. Using SERA colour indicator test kits, the levels of ammonium, nitrite and carbonate hardness were measured. The results obtained from this study clearly show that the advanced oxidation processes are more efficient in reducing the ammonium and nitrite levels in fish pond water than using ultrasound alone. The pH and carbonate hardness levels were not affected significantly by ultrasonic cavitation. The optimal treatment time and ultrasound power to treat the water samples were also established. Energy efficiency and cost analysis of this treatment have also been presented, indicating that ultrasonic cavitation coupled with hydrogen peroxide appears to be a promising technique for reducing total ammonia nitrogen levels in the fish pond water.
    Matched MeSH terms: Hydrogen Peroxide
  14. Fenton-like oxidation of reactive black 5 solution using iron-Montmorillonite K10 catalyst
    Daud NK, Hameed BH
    J Hazard Mater, 2010 Apr 15;176(1-3):1118-21.
    PMID: 20042286 DOI: 10.1016/j.jhazmat.2009.11.134
    Decolorization of reactive azo dye, reactive black 5 (RB5), was conducted using Fe(III) immobilized on Montmorillonite K10 (MK10) as a catalyst in the presence of H(2)O(2) using Fenton-like oxidation process. The effect of different parameters such as iron ions loading on supported catalyst, catalyst dosage, initial pH of dye solution, initial concentration of H(2)O(2) and dye and reaction temperature on the decolorization efficiency of the process were studied. The results indicated that by using 12 mM of H(2)O(2) and 3.50 g L(-1) of the 0.11 wt.% Fe(III) oxide on MK10 catalyst at pH of 2.5, 99% of decolorization efficiency was achieved within 150 min in a batch process.
    Matched MeSH terms: Hydrogen Peroxide/chemistry
  15. Fenton degradation of ofloxacin antibiotic using calcium alginate beads impregnated with Fe3O4-montmorillonite composite
    Ahmad ARD, Imam SS, Adnan R, Oh WD, Abdul Latip AF, Ahmad AAD
    Int J Biol Macromol, 2023 Feb 28;229:838-848.
    PMID: 36586654 DOI: 10.1016/j.ijbiomac.2022.12.287
    The primary aim of this study is to develop an economical, stable, and effective heterogeneous catalyst for wastewater remediation via the Fenton oxidation process. For this purpose, Fe3O4-montmorillonite alginate (FeMA) composite beads were synthesized by entrapping Fe3O4-montmorillonite in calcium alginate beads. The performance of the catalysts was evaluated via the Fenton degradation of ofloxacin (OFL), an antibiotic that is frequently detected in water bodies. The physiochemical properties of the FeMA composite beads were characterized using X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX), Brunauer-Emmett-Teller (BET) analysis, Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). FeMA composite beads were found to have a higher surface area, higher porosity, and better thermal stability compared to pristine alginate beads. The composite beads were subsequently used for Fenton degradation of ofloxacin (OFL) in an aqueous solution. The effects of Fe3O4-montmorillonite loading on alginate, FeMA composite beads dosage, initial solution pH, initial OFL concentration, different oxidants, H2O2 dosage, reaction temperature, and inorganic salts on Fenton degradation of OFL in aqueous solution was investigated. The results revealed that the percentage of OFL degradation reached about 80 % under optimized conditions, while the total organic carbon (TOC) removal reached about 53 %. The entrapment of Fe3O4-montmorillonite in alginate beads results in less iron ions leaching compared to previous observation, and the efficiency remains constant over the five cycles investigated. The kinetics of the Fenton degradation process are best fitted to the pseudo-first-order kinetic model. It is therefore believed that FeMA composite beads can be a promising material for wastewater remediation via the Fenton oxidation process.
    Matched MeSH terms: Hydrogen Peroxide/chemistry
  16. Fenton based remediation of polycyclic aromatic hydrocarbons-contaminated soils
    Yap CL, Gan S, Ng HK
    Chemosphere, 2011 Jun;83(11):1414-30.
    PMID: 21316731 DOI: 10.1016/j.chemosphere.2011.01.026
    This paper aims to review the applications of Fenton based treatments specifically for polycyclic aromatic hydrocarbons-contaminated soils. An overview of the background and principles of Fenton treatment catalysed by both homogenous (conventional and modified Fenton) and heterogeneous (Fenton-like) catalysts is firstly presented. Laboratory and field soil remediation studies are then discussed in terms of efficiency, kinetics and associated factors. Four main scopes of integrated Fenton treatments, i.e. physical-Fenton, biological-Fenton, electro-Fenton and photo-Fenton are also reviewed in this paper. For each of these integrated remediation technologies, the theoretical background and mechanisms are detailed alongside with achievable removal efficiencies for polycyclic aromatic hydrocarbons in contaminated soils compared to sole Fenton treatment. Finally, the environmental impacts of Fenton based soil treatments are documented and discussed.
    Matched MeSH terms: Hydrogen Peroxide/chemistry*
  17. Feasibility of treating aged polycyclic aromatic hydrocarbons (PAHs)-contaminated soils using ethyl lactate-based Fenton treatment via parametric and kinetic studies
    Yap CL, Gan S, Ng HK
    Environ Sci Pollut Res Int, 2015 Jan;22(1):329-42.
    PMID: 25065478 DOI: 10.1007/s11356-014-3199-7
    This study focuses on the feasibility of treating aged polycyclic aromatic hydrocarbons (PAHs)-contaminated soils using ethyl lactate (EL)-based Fenton treatment via a combination of parametric and kinetic studies. An optimised operating condition was observed at 66.7 M H2O2 with H2O2/Fe(2+) of 40:1 for low soil organic carbon (SOC) content and mildly acidic soil (pH 6.2), and 10:1 for high SOC and very acidic soil (pH 4.4) with no soil pH adjustment. The desorption kinetic was only mildly shifted from single equilibrium to dual equilibrium of the first-order kinetic model upon ageing. Pretreatment with EL fc = 0.60 greatly reduced the mass transfer coefficient especially for the slow desorbed fraction (kslow) of high molecular weight (HMW) PAHs, largely contributed by the concentration gradient created by EL-enhanced solubility. As the major desorption obstacle was almost fully overcome by the pretreatment, the pseudo-first-order kinetic reaction rate constant of PAHs degradation of aged soils was statistically discernible from that of freshly contaminated soils but slightly reduced in high SOC and high acidity soil. Stabilisation of H2O2 by EL addition in combination with reduced Fe(2+) catalyst were able to slow the decomposition rate of H2O2 even at higher soil pH.
    Matched MeSH terms: Hydrogen Peroxide/chemistry
  18. Facile synthesis of GO and g-C3N4 nanosheets encapsulated magnetite ternary nanocomposite for superior photocatalytic degradation of phenol
    Rehman GU, Tahir M, Goh PS, Ismail AF, Samavati A, Zulhairun AK, et al.
    Environ Pollut, 2019 Oct;253:1066-1078.
    PMID: 31434184 DOI: 10.1016/j.envpol.2019.07.013
    In this study, the synthesis of Fe3O4@GO@g-C3N4 ternary nanocomposite for enhanced photocatalytic degradation of phenol has been investigated. The surface modification of Fe3O4 was performed through layer-by-layer electrostatic deposition meanwhile the heterojunction structure of ternary nanocomposite was obtained through sonicated assisted hydrothermal method. The photocatalysts were characterized for their crystallinity, surface morphology, chemical functionalities, and band gap energy. The Fe3O4@GO@g-C3N4 ternary nanocomposite achieved phenol degradation of ∼97%, which was significantly higher than that of Fe3O4@GO (∼75%) and Fe3O4 (∼62%). The enhanced photoactivity was due to the efficient charge carrier separation and desired band structure. The photocatalytic performance was further enhanced with the addition of hydrogen peroxide, in which phenol degradation up to 100% was achieved in 2 h irradiation time. The findings revealed that operating parameters have significant influences on the photocatalytic activities. It was found that lower phenol concentration promoted higher activity. In this study, 0.3 g of Fe3O4@GO@g-C3N4 was found to be the optimized photocatalyst for phenol degradation. At the optimized condition, the reaction rate constant was reported as 6.96 × 10-3 min-1. The ternary photocatalyst showed excellent recyclability in three consecutive cycles, which confirmed the stability of this ternary nanocomposite for degradation applications.
    Matched MeSH terms: Hydrogen Peroxide
  19. Facile hydrothermal growth graphene/ZnO nanocomposite for development of enhanced biosensor
    Low SS, Tan MT, Loh HS, Khiew PS, Chiu WS
    Anal Chim Acta, 2016 Jan 15;903:131-41.
    PMID: 26709306 DOI: 10.1016/j.aca.2015.11.006
    Graphene/zinc oxide nanocomposite was synthesised via a facile, green and efficient approach consisted of novel liquid phase exfoliation and solvothermal growth for sensing application. Highly pristine graphene was synthesised through mild sonication treatment of graphite in a mixture of ethanol and water at an optimum ratio. The X-ray diffractometry (XRD) affirmed the hydrothermal growth of pure zinc oxide nanoparticles from zinc nitrate hexahydrate precursor. The as-prepared graphene/zinc oxide (G/ZnO) nanocomposite was characterised comprehensively to evaluate its morphology, crystallinity, composition and purity. All results clearly indicate that zinc oxide particles were homogenously distributed on graphene sheets, without any severe aggregation. The electrochemical performance of graphene/zinc oxide nanocomposite-modified screen-printed carbon electrode (SPCE) was evaluated using cyclic voltammetry (CV) and amperometry analysis. The resulting electrode exhibited excellent electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2) in a linear range of 1-15 mM with a correlation coefficient of 0.9977. The sensitivity of the graphene/zinc oxide nanocomposite-modified hydrogen peroxide sensor was 3.2580 μAmM(-1) with a limit of detection of 7.4357 μM. An electrochemical DNA sensor platform was then fabricated for the detection of Avian Influenza H5 gene based on graphene/zinc oxide nanocomposite. The results obtained from amperometry study indicate that the graphene/zinc oxide nanocomposite-enhanced electrochemical DNA biosensor is significantly more sensitive (P 
    Matched MeSH terms: Hydrogen Peroxide
  20. Facile and Affordable Design of MXene-Co3 O4 -Based Nanocomposites for Detection of Hydrogen Peroxide in Cancer Cells: Toward Portable Tool for Cancer Management
    Singh S, Numan A, Khalid M, Bello I, Panza E, Cinti S
    Small, 2023 Dec;19(51):e2208209.
    PMID: 37096900 DOI: 10.1002/smll.202208209
    Hydrogen peroxide (H2 O2 ) is a primary reactive oxygen species (ROS) that can act as a chemical signal in developing and progressing serious and life-threatening diseases like cancer. Due to the stressful nature of H2 O2 , there is an urgent need to develop sensitive analytical approaches to be applied to various biological matrices. Herein, a portable point-of-care electrochemical system based on MXene-Co3 O4 nanocomposites to detect H2 O2 in different cancer cell-lines is presented. The developed sensor is affordable, disposable, and highly selective for H2 O2 detection. This approach achieves a dynamic linear range of 75 µm with a LOD of 0.5 µm and a LOQ of 1.6 µm. To improve the practical application, the level of ROS is evaluated both in cancer cell lines MDA-MB-231 and DU145, respectively, to breast and prostate cancers, and in healthy HaCat cells. Moreover, the same cancer cells are treated with transforming growth factor-β1, and MXene-Co3 O4 modified strip is capable to monitorROS variation. The results are satisfactory compared with the cellular ROS fluorescent assay based on DCFH/DCFH-DA. These results open new perspectives for real-time monitoring of cancer progression and the efficacy of the therapy.
    Matched MeSH terms: Hydrogen Peroxide/metabolism
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links