Displaying publications 421 - 440 of 523 in total

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  1. Fulltext In vitro and ex-vivo cellular antioxidant protection and cognitive enhancing effects of an extract of Polygonum minus Huds (Lineminus™) demonstrated in a Barnes Maze animal model for memory and learning
    George A, Ng CP, O'Callaghan M, Jensen GS, Wong HJ
    BMC Complement Altern Med, 2014;14:161.
    PMID: 24886679 DOI: 10.1186/1472-6882-14-161
    Polygonum minus Huds.is a culinary flavouring that is common in South East Asian cuisine and as a remedy for diverse maladies ranging from indigestion to poor eyesight. The leaves of this herb have been reported to be high in antioxidants. Flavonoids which have been associated with memory, cognition and protection against neurodegeneration were found in P. minus.
    Matched MeSH terms: Oxidation-Reduction
  2. Fulltext Synthesis, characterisation, and evaluation of a cross-linked disulphide amide-anhydride-containing polymer based on cysteine for colonic drug delivery
    Lim V, Peh KK, Sahudin S
    Int J Mol Sci, 2013;14(12):24670-91.
    PMID: 24351841 DOI: 10.3390/ijms141224670
    The use of disulphide polymers, a low redox potential responsive delivery, is one strategy for targeting drugs to the colon so that they are specifically released there. The objective of this study was to synthesise a new cross-linked disulphide-containing polymer based on the amino acid cysteine as a colon drug delivery system and to evaluate the efficiency of the polymers for colon targeted drug delivery under the condition of a low redox potential. The disulphide cross-linked polymers were synthesised via air oxidation of 1,2-ethanedithiol and 3-mercapto-N-2-(3-mercaptopropionamide)-3-mercapto propionic anhydride (trithiol monomers) using different ratio combinations. Four types of polymers were synthesised: P10, P11, P151, and P15. All compounds synthesised were characterised by NMR, IR, LC-MS, CHNS analysis, Raman spectrometry, SEM-EDX, and elemental mapping. The synthesised polymers were evaluated in chemical reduction studies that were performed in zinc/acetic acid solution. The suitability of each polymer for use in colon-targeted drug delivery was investigated in vitro using simulated conditions. Chemical reduction studies showed that all polymers were reduced after 0.5-1.0 h, but different polymers had different thiol concentrations. The bacterial degradation studies showed that the polymers were biodegraded in the anaerobic colonic bacterial medium. Degradation was most pronounced for polymer P15. This result complements the general consensus that biodegradability depends on the swellability of polymers in an aqueous environment. Overall, these results suggest that the cross-linked disulphide-containing polymers described herein could be used as coatings for drugs delivered to the colon.
    Matched MeSH terms: Oxidation-Reduction
  3. Effect of MgO nanofillers on burst release reduction from hydrogel nanocomposites
    Hezaveh H, Muhamad II
    J Mater Sci Mater Med, 2013 Jun;24(6):1443-53.
    PMID: 23515904 DOI: 10.1007/s10856-013-4914-5
    In this study, MgO nanoparticles are applied to control the initial burst release by modification of matrix structure, thereby affecting the release mechanism. The effects of MgO nanofiller loading on the in vitro release of a model drug are investigated. Surface topography and release kinetics of hydrogel nanocomposites are also studied in order to have better insight into the release mechanism. It was found that the incorporation of MgO nanofillers can significantly decrease the initial burst release. The effect of genipin (GN) on burst release was also compared with MgO nanoparticles, and it was found that the impact of MgO on burst release reduction is more obvious than GN; however, GN cross-linking caused greater final release compared to blanks and nanocomposites. To confirm the capability of nanocomposite hydrogels to reduce burst release, the release of β-carotene in Simulated Gastric Fluid and Simulated Intestinal Fluid was also carried out. Thus, the application of MgO nanoparticles seems to be a promising strategy to control burst release.
    Matched MeSH terms: Oxidation-Reduction
  4. Modified PVA-alginate encapsulated photocatalyst ferro photo gels for Cr(VI) reduction
    Idris A, Misran E, Hassan N, Abd Jalil A, Seng CE
    J Hazard Mater, 2012 Aug 15;227-228:309-16.
    PMID: 22682796 DOI: 10.1016/j.jhazmat.2012.05.065
    In this study magnetic separable photocatalyst beads containing maghemite nanoparticles (γ-Fe(2)O(3)) in polyvinyl alcohol (PVA) polymer were prepared and used in the reduction of Cr(VI) to Cr(III) in an aqueous solution under sunlight. The unique superparamagnetic property of the photocatalyst contributed by the γ-Fe(2)O(3) and robust property of PVA polymer allow the magnetic beads to be recovered easily and reused for at least 7 times without washing. The concentration of γ-Fe(2)O(3) was varied from 8% (v/v) to 27% (v/v) and the results revealed that the beads with 8% (v/v) γ-Fe(2)O(3) exhibited the best performance where Cr(VI) was reduced to Cr(III) in only 30 min under sunlight. The use of the PVA has improved the bead properties and life cycle of beads which is in line with sustainable practices.
    Matched MeSH terms: Oxidation-Reduction
  5. Production and characterization of violacein by locally isolated Chromobacterium violaceum grown in agricultural wastes
    Ahmad WA, Yusof NZ, Nordin N, Zakaria ZA, Rezali MF
    Appl Biochem Biotechnol, 2012 Jul;167(5):1220-34.
    PMID: 22278051 DOI: 10.1007/s12010-012-9553-7
    The present work highlighted the production of violacein by the locally isolated Chromobacterium violaceum (GenBank accession no. HM132057) in various agricultural waste materials (sugarcane bagasse, solid pineapple waste, molasses, brown sugar), as an alternative to the conventional rich medium. The highest yield for pigment production (0.82 g L⁻¹) was obtained using free cells when grown in 3 g of sugarcane bagasse supplemented with 10% (v/v) of L-tryptophan. A much lower yield (0.15 g L⁻¹) was obtained when the cells were grown either in rich medium (nutrient broth) or immobilized onto sugarcane bagasse. Violacein showed similar chemical properties as other natural pigments based on the UV-Vis, Fourier transform infrared spectroscopy, thin-layer chromatography, nuclear magnetic resonance, and mass spectrometry analysis. The pigment is highly soluble in acetone and methanol, insoluble in water or non-polar organic solvents, and showed good stability between pH 5-9, 25-100 °C, in the presence of light metal ions and oxidant such as H₂O₂. However, violacein would be slowly degraded upon exposure to light. This is the first report on the use of cheap and easily available agricultural wastes as growth medium for violacein-producing C. violaceum.
    Matched MeSH terms: Oxidation-Reduction
  6. Solid-state fermentation of palm kernel cake with Aspergillus flavus in laterally aerated moving bed bioreactor
    Wong YP, Saw HY, Janaun J, Krishnaiah K, Prabhakar A
    Appl Biochem Biotechnol, 2011 May;164(2):170-82.
    PMID: 21080102 DOI: 10.1007/s12010-010-9124-8
    Solid-state fermentation (SSF) was employed to enhance the nutritive values of palm kernel cake (PKC) for poultry feeding. Aspergillus flavus was isolated from local PKC and utilized to increase the mannose content of PKC via the degradation of β-mannan in PKC; evaluation was done for batch SSF in Erlenmeyer flasks and in a novel laterally aerated moving bed (LAMB) bioreactor. The optimum condition for batch SSF in flasks was 110% initial moisture content, initial pH 6.0, 30 °C, 855 μm particle size, and 120 h of fermentation, yielding 90.91 mg mannose g⁻¹ dry PKC (5.9-fold increase). Batch SSF in the LAMB at the optimum condition yielded 79.61 mg mannose g⁻¹ dry PKC (5.5-fold increase) within just 96 h due to better heat and mass transfer when humidified air flowed radially across the PKC bed. In spite of a compromise of 12% reduction in mannose content when compared with the flasks, the LAMB facilitated good heat and mass transfer, and improved the mannose content of PKC in a shorter fermentation period. These attributes are useful for batch production of fermented PKC feed in an industrial scale.
    Matched MeSH terms: Oxidation-Reduction
  7. Fulltext Molybdate reduction by Pseudomonas sp. strain DRY2
    Shukor MY, Ahmad SA, Nadzir MM, Abdullah MP, Shamaan NA, Syed MA
    J Appl Microbiol, 2010 Jun;108(6):2050-8.
    PMID: 19968732 DOI: 10.1111/j.1365-2672.2009.04604.x
    To isolate and characterize a potent molybdenum-reducing bacterium.
    Matched MeSH terms: Oxidation-Reduction
  8. Biosensor based on glutamate dehydrogenase immobilized in chitosan for the determination of ammonium in water samples
    Azmi NE, Ahmad M, Abdullah J, Sidek H, Heng LY, Karuppiah N
    Anal Biochem, 2009 May 1;388(1):28-32.
    PMID: 19454217 DOI: 10.1016/j.ab.2009.02.005
    An optical biosensor based on glutamate dehydrogenase (GLDH) immobilized in a chitosan film for the determination of ammonium in water samples is described. The biosensor film was deposited on a glass slide via a spin-coating method. The ammonium was measured based on beta-nicotinamide adenine dinucleotide (NADH) oxidation in the presence of alpha-ketoglutaric acid at a wavelength of 340 nm. The biosensor showed optimum activity at pH 8. The optimum chitosan concentrations and enzyme loading were found to be at 2% (w/v) and 0.08 mg, respectively. Optimum concentrations of NADH and alpha-ketoglutaric acid both were obtained at 0.15 mM. A linear response of the biosensor was obtained in the ammonium concentration range of 0.005 to 0.5 mM with a detection limit of 0.005 mM. The reproducibility of the biosensor was good, with an observed relative standard deviation of 5.9% (n=8). The biosensor was found to be stable for at least 1 month when stored dry at 4 degrees C.
    Matched MeSH terms: Oxidation-Reduction
  9. Reduction of COD and color of dyeing effluent from a cotton textile mill by adsorption onto bamboo-based activated carbon
    Ahmad AA, Hameed BH
    J Hazard Mater, 2009 Dec 30;172(2-3):1538-43.
    PMID: 19740605 DOI: 10.1016/j.jhazmat.2009.08.025
    In this work, activated carbon was prepared from bamboo waste by chemical activation method using phosphoric acid as activating agent. The activated carbon was evaluated for chemical oxygen demand (COD) and color reduction of a real textile mill effluent. A maximum reduction in color and COD of 91.84% and 75.21%, respectively was achieved. As a result, the standard B discharge limit of color and COD under the Malaysian Environmental Quality act 1974 was met. The Freundlich isotherm model was found best to describe the obtained equilibrium adsorption data at 30 degrees C. The Brunauer-Emmett-Teller (BET) surface area, total pore volume and the average pore diameter were 988.23 m(2)/g, 0.69 cm(3)/g and 2.82 nm, respectively. Various functional groups on the prepared bamboo activated carbon (BAC) were determined from the FTIR results.
    Matched MeSH terms: Oxidation-Reduction
  10. Hexavalent chromium reduction by Acinetobacter haemolyticus isolated from heavy-metal contaminated wastewater
    Zakaria ZA, Zakaria Z, Surif S, Ahmad WA
    J Hazard Mater, 2007 Jul 19;146(1-2):30-8.
    PMID: 17188812
    Possible application of a locally isolated environmental isolate, Acinetobacter haemolyticus to remediate Cr(VI) contamination in water system was demonstrated. Cr(VI) reduction by A. haemolyticus seems to favour the lower concentrations (10-30 mg/L). However, incomplete Cr(VI) reduction occurred at 70-100 mg/L Cr(VI). Initial specific reduction rate increased with Cr(VI) concentrations. Cr(VI) reduction was not affected by 1 or 10 mM sodium azide (metabolic inhibitor), 10 mM of PO(4)3-, SO4(2-), SO(3)2-, NO3- or 30 mg/L of Pb(II), Zn(II), Cd(II) ions. However, heat treatment caused significant dropped in Cr(VI) reduction to less than 20% only. A. haemolyticus cells loses its shape and size after exposure to 10 and 50 mg Cr(VI)/L as revealed from TEM examination. The presence of electron-dense particles in the cytoplasmic region of the bacteria suggested deposition of chromium in the cells.
    Matched MeSH terms: Oxidation-Reduction
  11. Fulltext Toxic effect of high concentration of sonochemically synthesized polyvinylpyrrolidone-coated silver nanoparticles on Citrobacter sp. A1 and Enterococcus sp. C1
    Lau CP, Abdul-Wahab MF, Jaafar J, Chan GF, Abdul Rashid NA
    J Microbiol Immunol Infect, 2017 Aug;50(4):427-434.
    PMID: 26427880 DOI: 10.1016/j.jmii.2015.08.004
    BACKGROUND/PURPOSE: Currently, silver nanoparticles (AgNPs) have gained importance in various industrial applications. However, their impact upon release into the environment on microorganisms remains unclear. The aim of this study was to analyze the effect of polyvinylpyrrolidone-capped AgNPs synthesized in this laboratory on two bacterial strains isolated from the environment, Gram-negative Citrobacter sp. A1 and Gram-positive Enterococcus sp. C1.

    METHODS: Polyvinylpyrrolidone-capped AgNPs were synthesized by ultrasound-assisted chemical reduction. Characterization of the AgNPs involved UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. Citrobacter sp. A1 and Enterococcus sp. C1 were exposed to varying concentrations of AgNPs, and cell viability was determined. Scanning electron microscopy was performed to evaluate the morphological alteration of both species upon exposure to AgNPs at 1000 mg/L.

    RESULTS: The synthesized AgNPs were spherical in shape, with an average particle size of 15 nm. The AgNPs had different but prominent effects on either Citrobacter sp. A1 or Enterococcus sp. C1. At an AgNP concentration of 1000 mg/L, Citrobacter sp. A1 retained viability for 6 hours, while Enterococcus sp. C1 retained viability only for 3 hours. Citrobacter sp. A1 appeared to be more resistant to AgNPs than Enterococcus sp. C1. The cell wall of both strains was found to be morphologically altered at that concentration.

    CONCLUSION: Minute and spherical AgNPs significantly affected the viability of the two bacterial strains selected from the environment. Enterococcus sp. C1 was more vulnerable to AgNPs, probably due to its cell wall architecture and the absence of silver resistance-related genes.

    Matched MeSH terms: Oxidation-Reduction
  12. Fulltext Influence of Diet and Postmortem Ageing on Oxidative Stability of Lipids, Myoglobin and Myofibrillar Proteins and Quality Attributes of Gluteus Medius Muscle in Goats
    Adeyemi KD, Shittu RM, Sabow AB, Ebrahimi M, Sazili AQ
    PLoS One, 2016;11(5):e0154603.
    PMID: 27138001 DOI: 10.1371/journal.pone.0154603
    This study appraised the effects of dietary blend of 80% canola oil and 20% palm oil and postmortem ageing on oxidative stability, fatty acids and quality attributes of gluteus medius (GM) muscle in goats. Twenty-four Boer bucks were randomly allotted to diet supplemented with 0, 4 and 8% oil blend, fed for 100 days and slaughtered, and the GM muscle was subjected to a 7 d chill storage (4±1°C). Diet had no effect (P> 0.05) on the colour, drip loss, thiobarbituric acid-reactive substances (TBARS) value, free thiol, carbonyl, myoglobin and metmyoglobin contents, metmyoglobin reducing activity (MRA), antioxidant enzyme activities and abundance of myosin heavy chain (MHC) and actin in the GM muscle in goats. The meat from goats fed 4 and 8% oil blend had higher (P< 0.05) concentration of α and γ-tocopherol and abundance of troponin T compared with that from the control goats. The GM muscle from the oil-supplemented goats had lower (P< 0.05) concentration of C16:0 and greater (P< 0.05) concentration of C18:1n-9, C18:3n-3 and C20:5n-3 compared with that from the control goats. Nonetheless, diet did not affect (P< 0.05) the total fatty acid in the GM muscle in goats. Regardless of the diet, the free thiol and myoglobin contents, concentration of tocopherol and total carotenoids, MHC and MRA in the GM muscle decreased (P< 0.05) while carbonyl content, TBARS, drip loss and metmyoglobin content increased over storage. Dietary blend of 80% canola oil and 20% palm oil beneficially altered tissue lipids without hampering the oxidative stability of chevon.
    Matched MeSH terms: Oxidation-Reduction
  13. Fulltext Cadmium Sulphide-Reduced Graphene Oxide-Modified Photoelectrode-Based Photoelectrochemical Sensing Platform for Copper(II) Ions
    Ibrahim I, Lim HN, Huang NM, Pandikumar A
    PLoS One, 2016;11(5):e0154557.
    PMID: 27176635 DOI: 10.1371/journal.pone.0154557
    A photoelectrochemical (PEC) sensor with excellent sensitivity and detection toward copper (II) ions (Cu2+) was developed using a cadmium sulphide-reduced graphene oxide (CdS-rGO) nanocomposite on an indium tin oxide (ITO) surface, with triethanolamine (TEA) used as the sacrificial electron donor. The CdS nanoparticles were initially synthesized via the aerosol-assisted chemical vapor deposition (AACVD) method using cadmium acetate and thiourea as the precursors to Cd2+ and S2-, respectively. Graphene oxide (GO) was then dip-coated onto the CdS electrode and sintered under an argon gas flow (50 mL/min) for the reduction process. The nanostructured CdS was adhered securely to the ITO by a continuous network of rGO that also acted as an avenue to intensify the transfer of electrons from the conduction band of CdS. The photoelectrochemical results indicated that the ITO/CdS-rGO photoelectrode could facilitate broad UV-visible light absorption, which would lead to a higher and steady-state photocurrent response in the presence of TEA in 0.1 M KCl. The photocurrent decreased with an increase in the concentration of Cu2+ ions. The photoelectrode response for Cu2+ ion detection had a linear range of 0.5-120 μM, with a limit of detection (LoD) of 16 nM. The proposed PEC sensor displayed ultra-sensitivity and good selectivity toward Cu2+ ion detection.
    Matched MeSH terms: Oxidation-Reduction
  14. Water fraction of edible medicinal fern Stenochlaena palustris is a potent α-glucosidase inhibitor with concurrent antioxidant activity
    Chai TT, Kwek MT, Ong HC, Wong FC
    Food Chem, 2015 Nov 1;186:26-31.
    PMID: 25976787 DOI: 10.1016/j.foodchem.2014.12.099
    This study aimed to isolate a potent antiglucosidase and antioxidant fraction from Stenochlaena palustris. Extraction was performed with hexane, chloroform, ethyl acetate, methanol, and water. Antiglucosidase, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and ferric reducing antioxidant power (FRAP) assays found methanol extract (ME) to be the most active. Water fraction (WF) of ME was a stronger α-glucosidase inhibitor (EC50 2.9 μg/mL) than quercetin, with weak antiamylase activity. WF was a competitive α-glucosidase inhibitor. DPPH scavenging activity of WF (EC50 7.7 μg/mL) was weaker than quercetin. WF (EC50 364 μg/mL) was a stronger hydrogen peroxide scavenger than gallic acid (EC50 838 μg/mL) and was equally strong as quercetin in scavenging superoxide. WF possessed moderate copper chelating activity. WF was enriched in total phenolics (TP) and hydroxycinnamic acids (THC). TP correlated with antioxidant activity (R(2) > 0.76). Only THC correlated with antiglucosidase activity (R(2) = 0.86). Overall, WF demonstrated concurrent, potent antiglucosidase and antioxidant activities.
    Matched MeSH terms: Oxidation-Reduction
  15. α-Glucosidase activity of oleanolic acid and its oxidative metabolites: DFT and Docking studies
    Anouar el H, Zakaria NS, Alsalme A, Shah SA
    Mini Rev Med Chem, 2015;15(14):1148-58.
    PMID: 26205959
    A natural pentacyclic triterpenoid oleanolic acid 1 and its biotransformed metabolites 2-3 are potential α-glucosidase inhibitors. To elucidate the inhibitory mechanism of compounds 1, 2 and 3 against α-glucosidase, we calculated (i) their electronic and optical properties using DFT and TD-DFT at the B3LYP/6-31G(d) level in gas and IEF-PCM solvent; and (ii) their binding energies to α-glucosidase via docking study. DFT results showed that the α-glucosidase inhibtion is mainly depend on the polarity parameters of the studied compounds. Docking results revealed that the activity increased with binding energies (i.e. the stability of ligand-receptor complex). The specroscopic data of oleanolic acid 1 and its metabolites 2 and 3 are well predicetd for 13C NMR chemical shifts (R2=99%) and 1H NMR chemical shifts (R2=90%); and for (ii) UV/vis spectra. The assignments and interpretation of NMR chemical shifts and bathochromic shift of λMAX absorption bands are discussed.
    Matched MeSH terms: Oxidation-Reduction
  16. Vitamin E in cardiovascular disease: has the die been cast?
    Yusoff K
    Asia Pac J Clin Nutr, 2002;11 Suppl 7:S443-7.
    PMID: 12492632
    Cardiovascular disease, in particular coronary artery disease (CAD), remains the most important cause of morbidity and mortality in developed countries and, in the near future, more so in the developing world. Atherosclerotic plaque formation is the underlying basis for CAD. Growth of the plaque leads to coronary stenosis, causing a progressive decrease in blood flow that results in angina pectoris. Acute myocardial infarction and unstable angina were recently recognised as related to plaque rupture, not progressive coronary stenosis. Acute thrombus formation causes an abrupt coronary occlusion. The characteristics of the fibrin cap, contents of the plaque, rheological factors and active inflammation within the plaque contribute to plaque rupture. Oxidative processes are important in plaque formation. Oxidized low density lipoproteins (LDL) but not unoxidized LDL is engulfed by resident intimal macrophages, transforming them into foam cells which develop into fatty streaks, the precursors of the atherosclerotic plaque. Inflammation is important both in plaque formation and rupture. Animal studies have shown that antioxidants reduce plaque formation and lead to plaque stabilisation. In humans, high intakes of antioxidants are associated with lower incidence of CAD, despite high serum cholesterol levels. This observation suggests a role for inflammation in CAD and that reducing inflammation using antioxidants may ameliorate these processes. Men and women with high intakes of vitamin E were found to have less CAD. Vitamin E supplementation was associated with a significant reduction in myocardial infarction and cardiovascular events in the incidence of recurrent myocardial infarction. In the hierarchy of evidence in evidence-based medicine, data from large placebo-controlled clinical trials is considered necessary. Results from various mega-trials have not shown benefits (nor adverse effects) conferred by vitamin E supplementation, suggesting that vitamin E has no role in the treatment of CAD. These results do not seem to confirm, at the clinical level, the effect of antioxidants against active inflammation during plaque rupture. However, a closer examination of these studies showed a number of limitations, rendering them inconclusive in addressing the role of vitamin E in CAD prevention and treatment. Further studies that specifically address the issue of vitamin E in the pathogenesis of atherosclerosis and in the treatment of CAD need be performed. These studies should use the more potent antioxidant property of alpha-tocotrienol vitamin E.
    Matched MeSH terms: Oxidation-Reduction
  17. The effects of propranolol on skeletal muscle contraction, lipid peroxidation products and antioxidant activity in experimental hyperthyroidism
    Zaiton Z, Merican Z, Khalid BA, Mohamed JB, Baharom S
    Gen. Pharmacol., 1993 Jan;24(1):195-9.
    PMID: 8482496
    1. The mean levels of lipid peroxidation products, namely conjugated diene and malonaldehyde, were increased in the soleus muscles of hyperthyroid cats, while the mean glutathione peroxidase activity was decreased. No corresponding similar changes were noted in the fast extensor digitorum longus muscles and serum. 2. Propranolol administration prevented the increase in conjugated diene level in the soleus muscles of hyperthyroid cat but not the malonaldehyde level. It also prevented the reduction in glutathione peroxidase activity in the slow oxidative soleus muscles of hyperthyroid cats. 3. Maximal twitch tension, subtetanic tension and maximum tetanic tension of soleus and EDL muscles were reduced in hyperthyroid cats. Propranolol administration for 5 weeks to hyperthyroid cats did not prevent the reduction in tension of contractions of these muscles. 4. It is suggested that lipid peroxidation might not be responsible for the myopathy in hyperthyroidism and propranolol administration does not improve skeletal muscle function in hyperthyroid animals.
    Matched MeSH terms: Oxidation-Reduction
  18. Concentrations of thiocyanate and hypothiocyanite in the saliva of young adults
    Jalil RA
    J Nihon Univ Sch Dent, 1994 Dec;36(4):254-60.
    PMID: 7869127
    The study was conducted to determine thiocyanate (SCN-) and hypothiocyanite (OSCN-) concentrations in resting (RWS) and stimulated whole saliva (SWS) and stimulated parotid saliva (SPS) of 20 healthy young adults aged 21-29 y. Samples of saliva were collected at 12:30, immediately before lunch. Resting saliva was collected by expectoration, and stimulated saliva was collected during the uniform chewing of paraffin wax. Parotid secretion was collected using a modified Carlsson-Crittenden cup (Carlsson et al., Am, J. Physiol., 26, 169-177, 1910). SCN- concentration was determined by the ferric nitrate method (Betts et al., J. Am. Chem. Soc., 75, 5721-5727, 1953) whilst OSCN- was assayed using 2-mercaptoethanol as a reducing agent (Pruitt et al., Caries Res., 16, 315-323, 1982). In RWS, SWS and SPS, the mean SCN- concentrations (in mM) were 1.48 +/- 0.59(S.D.), 0.90 +/- 0.56(S.D.) and 1.24 +/- 0.65(S.D.) whilst the mean OSCN- concentrations (in microM) were 31.21 +/- 13.54(S.D.), 24.90 +/- 12.61 and 30.19 +/- 23.35(S.D.) in the respective salivas. The presence of OSCN- in the secretion collected from the parotid gland supported previous findings by Tenovuo and Pruitt (Tenovuo et al., J. Oral Path, ol. 13, 573-584, 1984), who suggested an endogenous glandular (eukaryotic) source of hydrogen peroxide (H2O2), since parotid saliva from healthy glands is devoid of bacteria and leukocytes.
    Matched MeSH terms: Oxidation-Reduction
  19. Quality assessment of refined red palm-pressed mesocarp olein
    Teh SS, Lau HLN
    Food Chem, 2021 Mar 15;340:127912.
    PMID: 32916404 DOI: 10.1016/j.foodchem.2020.127912
    Palm-pressed mesocarp oil has been found to contain plenty of naturally occurring valuable phytonutrients. The application and study of the oil are limited, therefore, quality assessment of refined red palm-pressed mesocarp olein (PPMO) is deemed necessary to provide data in widening the applications as a niche products or raw material for the nutraceutical industry. Results showed that refined PPMO has comparable physicochemical properties and oxidative stability with commercial cooking oil, palm olein (PO). The food safety parameters and contaminants (PAH, 3-MCPD ester, 2-MCPD ester, glycidyl ester and trace metals) analyses proven that refined PPMO is safe to be consumed. Besides, refined PPMO contains remarkably greater concentrations of phytonutrients including carotenoids, phytosterols, squalene and vitamin E than PO, postulating its protective health benefits. The overall quality assessment of refined PPMO showed that it is suitable for human consumption and it is a good source for food applications and dietary nutritional supplements.
    Matched MeSH terms: Oxidation-Reduction
  20. Ultrasensitive voltammetric detection of benzenediol isomers using reduced graphene oxide-azo dye decorated with gold nanoparticles
    Mohammed Modawe Alshik Edris N, Sulaiman Y
    Ecotoxicol Environ Saf, 2020 Oct 15;203:111026.
    PMID: 32888594 DOI: 10.1016/j.ecoenv.2020.111026
    The detection of phenolic compounds, i.e. resorcinol (RC) catechol (CC) and hydroquinone (HQ) are important due to their extremely hazardous impact and poor environmental degradation. In this work, a novel and sensitive composite of electrochemically reduced graphene oxide-poly(Procion Red MX-5B)/gold nanoparticles modified glassy carbon electrode (GCE/ERGO-poly(PR)/AuNPs) was assembled for voltammetric detection of benzenediol isomers (RC, CC, and HQ). The nanocomposite displayed high peak currents towards the oxidation of RC, HQ, and CC compared to non-modified GCE. The peak-to-peak separations were 0.44 and 0.10 V for RC-CC and CC-HQ, respectively. The limit of detections were 53, 53, and 79 nM for HQ, CC, and RC with sensitivities of 4.61, 4.38, and 0.56 μA/μM (S/N = 3), respectively. The nanocomposite displayed adequate reproducibility, besides good stability and acceptable recoveries for wastewater and cosmetic samples analyses.
    Matched MeSH terms: Oxidation-Reduction
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