Displaying publications 361 - 380 of 529 in total

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  1. Geo-accumulation index and contamination factors of heavy metals (Zn and Pb) in urban river sediment
    Haris H, Looi LJ, Aris AZ, Mokhtar NF, Ayob NAA, Yusoff FM, et al.
    Environ Geochem Health, 2017 Dec;39(6):1259-1271.
    PMID: 28484873 DOI: 10.1007/s10653-017-9971-0
    The aim of the present study was to appraise the levels of heavy metal contamination (Zn and Pb) in sediment of the Langat River (Selangor, Malaysia). Samples were collected randomly from 15 sampling stations located along the Langat River. The parameters measured were pH, redox potential, salinity, electrical conductivity, loss of ignition, cation exchanges capacity (Na, Mg, Ca, K), and metal ions (Zn and Pb). The geo-accumulation index (I geo) and contamination factor (C f) were applied to determine and classify the magnitude of heavy metal pollution in this urban river sediment. Results revealed that the I geo of Pb indicated unpolluted to moderately polluted sediment at most of the sampling stations, whereas Zn was considered to be within background concentration. The I geo results were refined by the C f values, which showed Pb with very high C f at 12 stations. Zinc, on the other hand, had low to moderate C f values. These findings indicated that the sediment of the Langat River is severely polluted with Pb. The Zn concentration at most sampling points was well below most sediment quality guidelines. However, 40% of the sampling points were found to have a Pb concentration higher than the consensus-based probable effect concentration of 128 mg/kg (concentrations above this value are likely to cause harmful effects). This result not only highlights the severity of Pb pollution in the sediment of the Langat River, but also the potential risk it poses to the environment.
    Matched MeSH terms: Oxidation-Reduction
  2. Novel combination of zero-valent Cu and Ag nanoparticles @ cellulose acetate nanocomposite for the reduction of 4-nitro phenol
    Khan FU, Asimullah, Khan SB, Kamal T, Asiri AM, Khan IU, et al.
    Int J Biol Macromol, 2017 Sep;102:868-877.
    PMID: 28428128 DOI: 10.1016/j.ijbiomac.2017.04.062
    A very simple and low-cost procedure has been adopted to synthesize efficient copper (Cu), silver (Ag) and copper-silver (Cu-Ag) mixed nanoparticles on the surface of pure cellulose acetate (CA) and cellulose acetate-copper oxide nanocomposite (CA-CuO). All nanoparticles loaded onto CA and CA-CuO presented excellent catalytic ability, but Cu-Ag nanoparticles loaded onto CA-CuO (Cu0-Ag0/CA-CuO) exhibited outstanding catalytic efficiency to convert 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) in the presence of NaBH4. Additionally, the Cu0-Ag0/CA-CuO can be easily recovered by removing the sheet from the reaction media, and can be recycled several times, maintaining high catalytic ability for four cycles.
    Matched MeSH terms: Oxidation-Reduction
  3. A new achievement in green degradation of aqueous organic pollutants under visible-light irradiation
    Abdollahi Y, Sabbaghi S, Abouzari-Lotf E, Jahangirian H, Sairi NA
    Water Sci Technol, 2018 Mar;77(5-6):1493-1504.
    PMID: 29595152 DOI: 10.2166/wst.2018.017
    The global attention has been focused on degradation of the environmental organic pollutants through green methods such as advanced oxidation processes (AOPs) under sunlight. However, AOPs have not yet been efficient in function of the photocatalyst that has been used. In this work, firstly, CaCu3Ti4O12 nanocomposite was simultaneously synthesized and decorated in different amounts of graphene oxide to enhance photodegradation of the organics. The result of the photocatalyst characterization showed that the sample with 8% graphene presented optimum photo-electrical properties such as low band gap energy and a great surface area. Secondly, the photocatalyst was applied for photodegradation of an organic model in a batch photoreactor. Thirdly, to scale up the process and optimize the efficiency, the photodegradation was modeled by multivariate semi-empirical methods. As the optimized condition showed, 45 mg/L of the methyl-orange has been removed at pH 5.8 by 0.96 g/L of the photocatalyst during 288 min of the light irradiation. Moreover, the photodegradation has been scaled up for industrial applications by determining the importance of the input effective variables according to the following organics order > photocatalyst > pH > irradiation time.
    Matched MeSH terms: Oxidation-Reduction
  4. Self-assembled three-dimensional reduced graphene oxide-based hydrogel for highly efficient and facile removal of pharmaceutical compounds from aqueous solution
    Umbreen N, Sohni S, Ahmad I, Khattak NU, Gul K
    J Colloid Interface Sci, 2018 Oct 01;527:356-367.
    PMID: 29843021 DOI: 10.1016/j.jcis.2018.05.010
    Herein, self-assembled three-dimensional reduced graphene oxide (RGO)-based hydrogels were synthesized and characterized in detail. A thorough investigation on the uptake of three widely used pharmaceutical drugs, viz. Naproxen (NPX), Ibuprofen (IBP) and Diclofenac (DFC) was carried out from aqueous solutions. To ensure the sustainability of developed hydrogel assembly, practically important parameters such as desorption, recyclability and applicability to real samples were also evaluated. Using the developed 3D hydrogels as adsorptive platforms, excellent decontamination for the above mentioned persistent pharmaceutical drugs was achieved in acidic pH with a removal efficiency in the range of 70-80%. These hydrogels showed fast adsorption kinetics and experimental findings were fitted to different kinetic models, such as pseudo-first order, pseudo-second order, intra-particle and the Elovich models in an attempt to better understand the adsorption kinetics. Furthermore, equilibrium adsorption data was fitted to the Langmuir and Freundlich models, where relatively higher R2 values obtained in case of former one suggested that monolayer adsorption played an important part in drug uptake. Thermodynamic aspects were also studied and negative ΔG0 values obtained indicated the spontaneous nature of adsorption process. The study was also extended to check practical utility of as-prepared hydrogels by spiking real aqueous samples with drug solution, where high % recoveries obtained for NPX, IBP and DFC were of particular importance with regard to prospective application in wastewater treatment systems. We advocate RGO-based hydrogels as environmentally benign, readily recoverable/recyclable material with excellent adsorption capacity for application in wastewater purification.
    Matched MeSH terms: Oxidation-Reduction
  5. Removal of VOCs from gas streams with double perovskite-type catalysts
    Pan KL, Pan GT, Chong S, Chang MB
    J Environ Sci (China), 2018 Jul;69:205-216.
    PMID: 29941256 DOI: 10.1016/j.jes.2017.10.012
    Double perovskite-type catalysts including La2CoMnO6 and La2CuMnO6 are first evaluated for the effectiveness in removing volatile organic compounds (VOCs), and single perovskites (LaCoO3, LaMnO3, and LaCuO3) are also tested for comparison. All perovskites are tested with the gas hourly space velocity (GHSV) of 30,000hr-1, and the temperature range of 100-600°C for C7H8 removal. Experimental results indicate that double perovskites have better activity if compared with single perovskites. Especially, toluene (C7H8) can be completely oxidized to CO2 at 300°C as La2CoMnO6 is applied. Characterization of catalysts indicates that double perovskites own unique surface properties and are of higher amounts of lattice oxygen, leading to higher activity. Additionally, apparent activation energy of 68kJ/mol is calculated using Mars-van Krevelen model for C7H8 oxidation with La2CoMnO6 as catalyst. For durability test, both La2CoMnO6 and La2CuMnO6 maintain high C7H8 removal efficiencies of 100% and 98%, respectively, at 300°C and 30,000hr-1, and they also show good resistance to CO2 (5%) and H2O(g) (5%) of the gas streams tested. For various VOCs including isopropyl alcohol (C3H8O), ethanal (C2H4O), and ethylene (C2H4) tested, as high as 100% efficiency could be achieved with double perovskite-type catalysts operated at 300-350°C, indicating that double perovskites are promising catalysts for VOCs removal.
    Matched MeSH terms: Oxidation-Reduction
  6. Sono-assisted TEMPO oxidation of oil palm lignocellulosic biomass for isolation of nanocrystalline cellulose
    Rohaizu R, Wanrosli WD
    Ultrason Sonochem, 2017 01;34:631-639.
    PMID: 27773290 DOI: 10.1016/j.ultsonch.2016.06.040
    Highly stable and dispersible nanocrystalline cellulose (NCC) was successfully isolated from oil palm empty fruit bunch microcrystalline cellulose (OPEFB-MCC), with yields of 93% via a sono-assisted TEMPO-oxidation and a subsequent sonication process. The sono-assisted treatment has a remarkable effect, resulting in an increase of more than 100% in the carboxylate content and a significant increase of approximately 39% in yield compared with the non-assisted process. TEM images reveal the OPEFB-NCC to have rod-like crystalline morphology with an average length and width of 122 and 6nm, respectively. FTIR and solid-state 13C-NMR analyses suggest that oxidation of cellulose chain hydroxyl groups occurs at C6. XRD analysis shows that OPEFB-NCC consists primarily of a crystalline cellulose I structure. Both XRD and 13C-NMR indicate that the OPEFB-NCC has a lower crystallinity than the OPEFB-MCC starting material. Thermogravimetric analysis illustrates that OPEFB-NCC is less thermally stable than OPEFB-MCC but has a char content of 46% compared with 7% for the latter, which signifies that the carboxylate functionality acts as a flame retardant.
    Matched MeSH terms: Oxidation-Reduction
  7. Hybrid membrane filtration-advanced oxidation processes for removal of pharmaceutical residue
    Rosman N, Salleh WNW, Mohamed MA, Jaafar J, Ismail AF, Harun Z
    J Colloid Interface Sci, 2018 Dec 15;532:236-260.
    PMID: 30092507 DOI: 10.1016/j.jcis.2018.07.118
    Reports of pharmaceuticals exist in surface water and drinking water around the world, indicate they are ineffectively remove from water and wastewater using conventional treatment technologies. The potential of adverse effect of these pharmaceuticals on public health and aquatic life, also their continuos accumulation have raised the development of water treatment technologies. Hybrid treatment processes like membrane filtration and advance oxidation processes (AOPs) are likely to give rise to efficient simultaneous degradation and separation mechanisms. Conventional membrane filtration techniques can remove the majority of contaminants, but the smallest, undegraded, and stabilized pharmaceutical wastes persist in the treated water. After some 20 years, researchers have recognized the important role of AOPs in the treatment of pharmaceutical wastewater because these technologies are capable of oxidizing recalcitrant, toxic, and non-biodigradable compounds into numerous by-products and finally, inert end-products via the intermediacy of hydroxyl and other radicals. Evidently, membranes are subjected to the fouling phenomenon by the contaminants in wastewater, hence resulting in a reduction of clean water flux and increase in energy demand. In such situations, these membrane hybrid AOPs exert a complementary effect in the elimination of membrane fouling, thus enhancing the performance of the membrane. Therefore, in this review, we describe the basic aspects of the removal and transformation of certain pharmaceuticals via membranes and AOPs. In addition, information and evidences on membrane hybrid AOPs in the field of pharmaceutical wastewater treatment is also presented.
    Matched MeSH terms: Oxidation-Reduction
  8. Fulltext Taurine protects against retinal and optic nerve damage induced by endothelin-1 in rats via antioxidant effects
    Nor Arfuzir NN, Agarwal R, Iezhitsa I, Agarwal P, Sidek S, Ismail NM
    Neural Regen Res, 2018 Nov;13(11):2014-2021.
    PMID: 30233077 DOI: 10.4103/1673-5374.239450
    Endothelin-1 (ET-1), a potent vasoconstrictor, is involved in retinal vascular dysregulation and oxidative stress in glaucomatous eyes. Taurine (TAU), a naturally occurring free amino acid, is known for its neuroprotective and antioxidant properties. Hence, we evaluated its neuroprotective properties against ET-1 induced retinal and optic nerve damage. ET-1 was administered intravitreally to Sprague-Dawley rats and TAU was injected as pre-, co- or post-treatment. Animals were euthanized seven days post TAU injection. Retinae and optic nerve were examined for morphology, and were also processed for caspase-3 immunostaining. Retinal redox status was estimated by measuring retinal superoxide dismutase, catalase, glutathione, and malondialdehyde levels using enzyme-linked immuosorbent assay. Histopathological examination showed significantly improved retinal and optic nerve morphology in TAU-treated groups. Morphometric examination showed that TAU pre-treatment provided marked protection against ET-1 induced damage to retina and optic nerve. In accordance with the morphological observations, immunostaining for caspase showed a significantly lesser number of apoptotic retinal cells in the TAU pre-treatment group. The retinal oxidative stress was reduced in all TAU-treated groups, and particularly in the pre-treatment group. The findings suggest that treatment with TAU, particularly pre-treatment, prevents apoptosis of retinal cells induced by ET-1 and hence prevents the changes in the morphology of retina and optic nerve. The protective effect of TAU against ET-1 induced retinal and optic nerve damage is associated with reduced retinal oxidative stress.
    Matched MeSH terms: Oxidation-Reduction
  9. Modulation of age related protein expression changes by gelam honey in cardiac mitochondrial rats
    Hasenan SM, Karsani SA, Jubri Z
    Exp Gerontol, 2018 11;113:1-9.
    PMID: 30248357 DOI: 10.1016/j.exger.2018.09.001
    Aging is characterized by progressive decline in biochemical and physiological functions. According to the free radical theory of aging, aging results from oxidative damage due to the accumulation of excess reactive oxygen species (ROS). Mitochondria are the main source of ROS production and are also the main target for ROS. Therefore, a diet high in antioxidant such as honey is potentially able to protect the body from ROS and oxidative damage. Gelam honey is higher in flavonoid content and phenolic compounds compared to other local honey. This study was conducted to determine the effects of gelam honey on age related protein expression changes in cardiac mitochondrial rat. A total of 24 Sprague-Dawley male rats were divided into two groups: the young group (2 months old), and aged group (19 months old). Each group were then subdivided into two groups: control group (force-fed with distilled water), and treatment group (force-fed with gelam honey, 2.5 g/kg), and were treated for 8 months. Comparative proteomic analysis of mitochondria from cardiac tissue was then performed by high performance mass spectrometry (Q-TOF LCMS/MS) followed by validation of selected proteins by Western blotting. Proteins were identified using Spectrum Mill software and were subjected to stringent statistical analysis. A total of 286 proteins were identified in the young control group (YC) and 241 proteins were identified in the young gelam group (YG). In the aged group, a total of 243 proteins were identified in control group (OC), and 271 proteins in gelam group (OG). Comparative proteome profiling identified 69 proteins with different abundance (p 
    Matched MeSH terms: Oxidation-Reduction
  10. Stability indicating HPLC method for simultaneous quantification of sildenafil citrate and dapoxetine hydrochloride in Pharmaceutical products
    Liew KB, Peh KK
    Pak J Pharm Sci, 2018 Nov;31(6):2515-2522.
    PMID: 30473526
    A stability-indicating HPLC-UV method for the simultaneous determination of sildenafil citrate and dapoxetine hydrochloride in solution and tablet was developed. The mobile phase was comprised of acetonitrile and 0.2M ammonium acetate buffer. The analyte was eluted at 3.392min and 7.255min for sildenafil citrate and dapoxetine HCl respectively using gradient system at a flow rate of 1.5mL/min. The theoretical plates count was>2000, tailing factor
    Matched MeSH terms: Oxidation-Reduction
  11. Fulltext Simultaneous biological nitrification and desulfurization treatment of ammonium and sulfide-rich wastewater: Effectiveness of a sequential batch operation
    Sekine M, Akizuki S, Kishi M, Kurosawa N, Toda T
    Chemosphere, 2020 Apr;244:125381.
    PMID: 31805460 DOI: 10.1016/j.chemosphere.2019.125381
    Sulfide inhibition to nitrifying bacteria has prevented the integration of digestate nitrification and biogas desulfurization to simplify anaerobic digestion systems. In this study, liquid digestate with NaHS solution was treated using nitrifying sludge in a sequential-batch reactor with a long fill period, with an ammonium loading rate of 293 mg-N L-1 d-1 and a stepwise increase in the sulfide loading rate from 0 to 32, 64, 128, and 256 mg-S L-1 d-1. Batch bioassays and microbial community analysis were also conducted with reactor sludge under each sulfide loading rate to quantify the microbial acclimatization to sulfide. In the reactor, sulfide was completely removed. Complete nitrification was maintained up to a sulfide load of 128 mg-S L-1 d-1, which is higher than that in previous reports and sufficient for biogas treatment. In the batch bioassays, the sulfide tolerance of NH4+ oxidizing activity (the 50% inhibitory sulfide concentration) increased fourfold over time with the compositional shift of nitrifying bacteria to Nitrosomonas nitrosa and Nitrobacter spp. However, the sulfur removal rate of the sludge slightly decreased, although the abundance of the sulfur-oxidizing bacteria Hyphomicrobium increased by 30%. Therefore, nitrifying sludge was probably acclimatized to sulfide not by the increasing sulfide removal rate but rather by the increasing nitrifying bacteria, which have high sulfide tolerance. Successful simultaneous nitrification and desulfurization were achieved using a sequential-batch reactor with a long fill period, which was effective in facilitating the present acclimatization.
    Matched MeSH terms: Oxidation-Reduction
  12. Hydroxyl radical formation in the hybrid system of photocatalytic fuel cell and peroxi-coagulation process affected by iron plate and UV light
    Nordin N, Ho LN, Ong SA, Ibrahim AH, Abdul Rani AL, Lee SL, et al.
    Chemosphere, 2020 Apr;244:125459.
    PMID: 31790991 DOI: 10.1016/j.chemosphere.2019.125459
    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.
    Matched MeSH terms: Oxidation-Reduction
  13. Ameliorative Effect of palm oil tocotrienol rich fraction on brain oxidative stress in Fenitrothion-administered rats
    Siti Balkis Budin, Izatus Shima Taib, Putri Ayu Jayusman, Hui HC, Ramalingam A, Ahmad Rohi Ghazali, et al.
    Sains Malaysiana, 2014;43:1031-1036.
    Fenitrothion (FNT) usage has received much attention for its potential to promote free radicals generation and interfere with antioxidant defense system. The aim of the present study was to investigate the effect of palm oil tocotrienol rich fraction (TRF) supplementation on oxidative stress and histological changes in rat brain induced by FNT. A total of 32 male Sprague Dawley rats divided into four groups: control group which received corn oil; TRF group was received palm oil TRF (200 mg/kg bw); FNT group administered with FNT (20 mg/kg bw) and TRF+FNT group pretreated with palm oil TRF (200 mg/kg bw) 30 min prior to administration of FNT (20 mg/kg bw). FNT and TRF were dissolved in corn oil and all supplementations were given by oral gavage once daily for 28 days. After four weeks of supplementation, TRF+FNT rats had significantly lower malondialdehyde (MDA) content and superoxide dismutase (SOD) activity but higher reduced glutathione (GSH) level and total protein level compared to FNT rats (p<0.05). However, protein carbonyl (PC) level was insignificantly lower for TRF+FNT group compared to FNT group. In conclusion, this study suggested that palm oil TRF was effective in preventing brain damage in rats.
    Matched MeSH terms: Oxidation-Reduction
  14. Identification of Novel Sesamol Dimers with Unusual Methylenedioxy Ring-Opening Skeleton and Evaluation of Their Antioxidant and Cytotoxic Activities
    Murthy S, Hazli UHAM, Kong KW, Mai CW, Leong CO, Rahman NA, et al.
    Curr Org Synth, 2019;16(8):1166-1173.
    PMID: 31984923 DOI: 10.2174/1570179416666191003095253
    BACKGROUND: Sesamol is a widely used antioxidant for the food and pharmaceutical industries. The oxidation products of this compound may be accumulated in foods or ingested. Little is known about its effect on human health.

    OBJECTIVE: It is of great interest to identify the oxidation products of sesamol that may be beneficial to humans. This study was undertaken to identify the oxidation products of sesamol and investigate their antioxidant and cytotoxic activities.

    MATERIALS AND METHODS: Using the ferricyanide oxidation approach, four oxidation products of sesamol (2, 3, 20 & 21) have been identified. Structural elucidation of these compounds was established on the basis of their detailed NMR spectroscopic analysis, mass spectrometry and x-ray crystallography. Additionally, a formation mechanism of compound 20 was proposed based on high-resolution mass spectrometry-fragmentation method. The antioxidant activities of these compounds were determined by the DPPH, FRAP, and ABTS assays. The in vitro antiproliferative activity of these compounds was evaluated against a panel of human cancer cell lines as well as non-cancerous cells.

    RESULTS: Two oxidation products of sesamol were found to contain an unusual methylenedioxy ring-opening skeleton, as evidenced by spectroscopic and x-ray crystallographic data. Among all compounds, 20 displayed impressive antiproliferative activities against a panel of human cancer cell lines yet remained non-toxic to noncancerous cells. The antioxidant activities of compound 20 are significantly weaker than sesamol as determined by the DPPH, FRAP, and ABTS assays.

    CONCLUSION: The oxidation products of sesamol could be a valuable source of bioactive molecules. Compound 20 may be used as a potential lead molecule for cancer studies.

    Matched MeSH terms: Oxidation-Reduction
  15. Quantitation of Protein Cysteine-Phenol Adducts in Minced Beef Containing 4-Methyl Catechol
    Arsad SS, Zainudin MAM, De Gobba C, Jongberg S, Larsen FH, Lametsch R, et al.
    J Agric Food Chem, 2020 Feb 26;68(8):2506-2515.
    PMID: 32013414 DOI: 10.1021/acs.jafc.9b07752
    Thiol groups of cysteine (Cys) residues in proteins react with quinones, oxidation products of polyphenols, to form protein-polyphenol adducts. The aim of the present work was to quantify the amount of adduct formed between Cys residues and 4-methylcatechol (4MC) in minced beef. A Cys-4MC adduct standard was electrochemically synthesized and characterized by liquid chromatography-mass spectrometry (LC-MS) as well as NMR spectroscopy. Cys-4MC adducts were quantified after acidic hydrolysis of myofibrillar protein isolates (MPIs) and LC-MS/MS analysis of meat containing either 500 or 1500 ppm 4MC and stored at 4 °C for 7 days under a nitrogen or oxygen atmosphere. The concentrations of Cys-4MC were found to be 2.2 ± 0.3 nmol/mg MPI and 8.1 ± 0.9 nmol/mg MPI in meat containing 500 and 1500 ppm 4MC, respectively, and stored for 7 days under oxygen. The formation of the Cys-4MC adduct resulted in protein thiol loss, and ca. 62% of the thiol loss was estimated to account for the formation of the Cys-4MC adduct for meat containing 1500 ppm 4MC. Furthermore, protein polymerization increased in samples containing 4MC as evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and the polymerization was found to originate from protein-polyphenol interactions as evaluated by a blotting assay with staining by nitroblue tetrazolium.
    Matched MeSH terms: Oxidation-Reduction
  16. In vitro apatite mineralization and heat generation of magnetite-reduced graphene oxide nanocomposites for hyperthermia treatment
    Miyazaki T, Akaike J, Kawashita M, Lim HN
    Mater Sci Eng C Mater Biol Appl, 2019 Jun;99:68-72.
    PMID: 30889741 DOI: 10.1016/j.msec.2019.01.091
    Nanocomposites of magnetite (Fe3O4) and reduced graphene oxide (rGO) generate heat under an alternating magnetic field and therefore have potential applications as thermoseeds for cancer hyperthermia treatment. However, the properties of such nanocomposites as biomaterials have not been sufficiently well characterized. In this study, the osteoconductivity of Fe3O4-rGO nanocomposites of various compositions was evaluated in vitro in terms of their apatite-forming ability in simulated body fluid (SBF). Furthermore, the heat generation of the nanocomposites was measured under an alternating magnetic field. The apatite-forming ability in SBF improved as the Fe3O4 content in the nanocomposite was increased. As the Fe3O4 content was increased, the nanocomposite not only rapidly raised the surrounding temperature to approximately 100 °C, but the specific absorption rate also increased. We assumed that the ionic interaction between the Fe3O4 and rGO was enhanced and that Brown relaxation was suppressed as the proportion of rGO in the nanocomposite was increased. Consequently, a high content of Fe3O4 in the nanocomposite was effective for improving both the osteoconductivity and heat generation characteristics for hyperthermia applications.
    Matched MeSH terms: Oxidation-Reduction
  17. Effect of external hydrazine addition on anammox reactor start-up time
    Ganesan S, Vadivelu VM
    Chemosphere, 2019 May;223:668-674.
    PMID: 30802832 DOI: 10.1016/j.chemosphere.2019.02.104
    Hydrazine is an intermediate product of the anaerobic ammonium oxidation (Anammox) process where both ammonium and nitrite in wastewater are converted to nitrogen gas by bacteria. In this study the effect of external hydrazine addition (5, 10, 15, and 20 mg/L) on the start-up period of the Anammox process was studied using sequencing batch reactors (SBRs). The SBR with an addition of 10 mg/L hydrazine took only 7 weeks to stabilize and achieve the maximum removal of ammonium and nitrite, whereas the SBR without the addition of hydrazine took 12 weeks. The amount of Heme C extracted from the biomass indicated that externally added hydrazine accelerated the growth of Anammox bacteria and reduced the release of nitrous oxide gas from the reactors.
    Matched MeSH terms: Oxidation-Reduction
  18. Synthesis of γ-N-modified 8-oxo-2'-deoxyguanosine triphosphate and its characterization
    Thavoncharoensub N, Maruyama K, Heh CH, Hoong Leong K, Shi H, Shigematsu Y, et al.
    Nucleosides Nucleotides Nucleic Acids, 2019;38(8):578-589.
    PMID: 30929604 DOI: 10.1080/15257770.2019.1586919
    8-OxodGTP is generated by the reaction between dGTP and reactive oxygen species and a considered mutagenic nucleotide. It can be incorporated into the duplex DNA during replication processes by the DNA polymerase, and thus the repair enzyme removes oxodGTP from the nucleotide pools in living cells. On the other hand, the γ-modified triphosphates show interesting properties for use as biological tools. Therefore, the γ-N-pyrenylalkyl-oxodGTP derivatives were synthesized and their effect on the enzymatic reactions were evaluated. The γ-N-pyrenylmethyl-oxodGTP was found to be accepted by the DNA polymerase just like oxodGTP, but showed a competitive inhibition property for the human oxodGTPase.
    Matched MeSH terms: Oxidation-Reduction
  19. A review on the advanced leachate treatment technologies and their performance comparison: an opportunity to keep the environment safe
    Show PL, Pal P, Leong HY, Juan JC, Ling TC
    Environ Monit Assess, 2019 Mar 18;191(4):227.
    PMID: 30887225 DOI: 10.1007/s10661-019-7380-9
    Landfill application is the most common approach for biowaste treatment via leachate treatment system. When municipal solid waste deposited in the landfills, microbial decomposition breaks down the wastes generating the end products, such as carbon dioxide, methane, volatile organic compounds, and liquid leachate. However, due to the landfill age, the fluctuation in the characteristics of landfill leachate is foreseen in the leachate treatment plant. The focuses of the researchers are keeping leachate from contaminating groundwater besides keeping potent methane emissions from reaching the atmosphere. To address the above issues, scientists are required to adopt green biological methods to keep the environment safe. This review focuses on the assorting of research papers on organic content and nitrogen removal from the leachate via recent effective biological technologies instead of conventional nitrification and denitrification process. The published researches on the characteristics of various Malaysian landfill sites were also discussed. The understanding of the mechanism behind the nitrification and denitrification process will help to select an optimized and effective biological treatment option in treating the leachate waste. Recently, widely studied technologies for the biological treatment process are aerobic methane oxidation coupled to denitrification (AME-D) and partial nitritation-anammox (PN/A) process, and both were discussed in this review article. This paper gives the idea of the modification of the conventional treatment technologies, such as combining the present processes to make the treatment process more effective. With the integration of biological process in the leachate treatment, the effluent discharge could be treated in shortcut and novel pathways, and it can lead to achieving "3Rs" of reduce, reuse, and recycle approach.
    Matched MeSH terms: Oxidation-Reduction
  20. Dietary UKMR-1 roselle supplementation prevents nicotine-induced cardiac injury by inhibiting myocardial oxidative stress
    Ramalingam A, Siti Balkis Budin, Lim Yc, Lislivia Si Yn, Satirah Zainalabidin
    Sains Malaysiana, 2016;45:1131-1137.
    UKMR-1, a local variant of mutant Roselle strain (Hibiscus sabdariffa) is enriched with free radical scavenging polyphenols
    such as anthocyanin, vitamin C and hydroxycitric acid. However, pharmacological actions of UKMR-1 are not fully known.
    This study was conducted to determine whether supplementation of aqueous UKMR-1 calyx extract was able to protect
    against nicotine-induced cardiac injury in rats. In this experimental study, healthy male albino rats were randomly
    allotted into three groups (n=7 per group): control, nicotine and UKMR-1+Nicotine groups. Nicotine (0.6 mg/kg, i.p.)
    was administered to both nicotine and UKMR-1+Nicotine groups for 28 consecutive days. UKMR-1+Nicotine group also
    received 100 mg/kg UKMR-1 extract orally via gavage 30 min prior to nicotine injection, daily. UKMR-1+Nicotine group
    had significantly (p<0.05) higher lactate dehydrogenase (LDH) activity, as well as lower malondialdehyde content in
    heart tissue homogenate than nicotine group, suggesting its cardio protective activity by inhibition of lipid peroxidation.
    UKMR-1 also lowered (p<0.05) the blood pressure in nicotine-administered rats. In addition, UKMR-1 significantly (p<0.05)
    restored activities of cytosolic superoxide dismutase, glutathione peroxidase and glutathione-S-transferase as well as
    redox balance ratio (GSH:GSSG). In conclusion, UKMR-1 was a
    Matched MeSH terms: Oxidation-Reduction
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