Journal articles: 'Specific oxidation rate'

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Fujita, M., K. Tsuji, and A. Akashi. "Temporal variation in maximum cell-specific nitrification rate." Water Science and Technology 61, no. 8 (April 1, 2010): 2069–73. http://dx.doi.org/10.2166/wst.2010.978.

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The cell numbers of ammonia-oxidising bacteria (AOBs), Nitrospira and Nitrobacter in activated sludge used to treat wastewater from a thermal power plant in Japan were examined for nine months using a real-time PCR quantification technique. AOB cell numbers ranged 2.8 × 1010–2.3 × 1011 cell/L. The amoA clone analysis showed that the only Nitrosomonas halophila was responsible for ammonia oxidation over the period. Nitrospira were in the range of 2.6 × 109–2.4 × 1010 cell/L and Nitrobacter were less than 1% as common as Nitrospira. Meanwhile, maximum nitrification rates, maximum ammonia- and nitrite-oxidation rates obtained from aerobic batch tests, ranged 0.5–1.3 mmol-N/L h and 1.0–2.5 mmol-N/L h, respectively. No clear correlations were observed between the cell numbers of AOBs or Nitrospira and their maximum rates, because the maximum cell-specific ammonia- and nitrite-oxidation rates varied remarkably over the ranges of 1.1–11.9 and 2.4–21.6 fmol-N/cell h, respectively. To explore the factors controlling maximum cell-specific nitrification rates, the relationship to influent nitrogen loads per AOB or Nitrospira cell numbers was investigated. Fairly good correlations were obtained. Considering the effluent ammonia and nitrite concentrations were zero and only Nitrosomonas halophila had a role in ammonia oxidation over the period, we conclude that the amount of nitrogen oxidised per AOB or Nitrospira cell numbers likely controls maximum cell-specific ammonia- or nitrite-oxidation rates, respectively.

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TSUJI, Koji, Masafumi FUJITA, Tetsuo YAMASHITA, Takashi MINO, and Akira AKASHI. "Response of Maximum Cell-Specific Nitrite Oxidation Rate to Hysteresis of Nitrite Oxidation by Nitrite-Oxidation Bacteria." Journal of Japan Society on Water Environment 31, no. 11 (2008): 693–99. http://dx.doi.org/10.2965/jswe.31.693.

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Blair, Megan C., Michael D. Neinast, and Zoltan Arany. "Whole-body metabolic fate of branched-chain amino acids." Biochemical Journal 478, no. 4 (February 24, 2021): 765–76. http://dx.doi.org/10.1042/bcj20200686.

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Oxidation of branched-chain amino acids (BCAAs) is tightly regulated in mammals. We review here the distribution and regulation of whole-body BCAA oxidation. Phosphorylation and dephosphorylation of the rate-limiting enzyme, branched-chain α-ketoacid dehydrogenase complex directly regulates BCAA oxidation, and various other indirect mechanisms of regulation also exist. Most tissues throughout the body are capable of BCAA oxidation, and the flux of oxidative BCAA disposal in each tissue is influenced by three key factors: 1. tissue-specific preference for BCAA oxidation relative to other fuels, 2. the overall oxidative activity of mitochondria within a tissue, and 3. total tissue mass. Perturbations in BCAA oxidation have been implicated in many disease contexts, underscoring the importance of BCAA homeostasis in overall health.

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Morash, Andrea J., Aleksandra O. Kotwica, and Andrew J. Murray. "Tissue-specific changes in fatty acid oxidation in hypoxic heart and skeletal muscle." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 305, no. 5 (September 1, 2013): R534—R541. http://dx.doi.org/10.1152/ajpregu.00510.2012.

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Exposure to hypobaric hypoxia is sufficient to decrease cardiac PCr/ATP and alters skeletal muscle energetics in humans. Cellular mechanisms underlying the different metabolic responses of these tissues and the time-dependent nature of these changes are currently unknown, but altered substrate utilization and mitochondrial function may be a contributory factor. We therefore sought to investigate the effects of acute (1 day) and more sustained (7 days) hypoxia (13% O2) on the transcription factor peroxisome proliferator-activated receptor α (PPARα) and its targets in mouse cardiac and skeletal muscle. In the heart, PPARα expression was 40% higher than in normoxia after 1 and 7 days of hypoxia. Activities of carnitine palmitoyltransferase (CPT) I and β-hydroxyacyl-CoA dehydrogenase (HOAD) were 75% and 35% lower, respectively, after 1 day of hypoxia, returning to normoxic levels after 7 days. Oxidative phosphorylation respiration rates using palmitoyl-carnitine followed a similar pattern, while respiration using pyruvate decreased. In skeletal muscle, PPARα expression and CPT I activity were 20% and 65% lower, respectively, after 1 day of hypoxia, remaining at this level after 7 days with no change in HOAD activity. Oxidative phosphorylation respiration rates using palmitoyl-carnitine were lower in skeletal muscle throughout hypoxia, while respiration using pyruvate remained unchanged. The rate of CO2 production from palmitate oxidation was significantly lower in both tissues throughout hypoxia. Thus cardiac muscle may remain reliant on fatty acids during sustained hypoxia, while skeletal muscle decreases fatty acid oxidation and maintains pyruvate oxidation.

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Nguyen, V. H., A. S. Filimono, B. V. Peshnev, and A. I. Nikolaev. "OXIDATION OF DISPERSE CARBON MATERIALS." Fine Chemical Technologies 13, no. 3 (June 28, 2018): 57–63. http://dx.doi.org/10.32362/24106593-2018-13-3-57-63.

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It is proposed to consider the process of carbon materials oxidative activation from the positions of topochemical reactions involving chemisorption of the activating agent (oxidizer) on the material surface active centers followed by chemical interaction. Such an approach makes it possible to control the process of creating a carbon material with the desired characteristics of the porous space. It is assumed that the oxidizer chemisorption active centers are amorphous carbon, which is localized on the material crystallites boundaries. The change in the length of these boundaries will lead to a change in the process rate. It is shown that the number of such active centers on the carbon material surface depends on the size of the crystallites. It will have a significant impact not only on the rate of activation, but also on the possibility of the process flow on the surface or with porosity formation. Mathematical models describing the carbon sample specific surface changing in the oxidation process are proposed. They allow quantifying the proportion of carbon that is oxidized on the sample surface or with pores formation, as well as quantifying the number of pores. It is shown that the ratio of pore formation and surface oxidation processes depends on the oxidation temperature, the oxidizer nature and its flow rate. The proportion of porosity formation decreases with the increase in the oxidant flow rate and the increase in temperature. It was experimentally shown that in order to obtain a material with a more developed porous space and a high specific surface it is preferable to use carbon dioxide as an oxidizing agent.

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Asamoah, Richmond K. "Specific Refractory Gold Flotation and Bio-Oxidation Products: Research Overview." Minerals 11, no. 1 (January 19, 2021): 93. http://dx.doi.org/10.3390/min11010093.

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This paper presents a research overview, reconciling key and useful case study findings, towards uncovering major causes of gold refractoriness and maximising extraction performance of specific gold flotation and bio-oxidation products. Through systematic investigation of the ore mineralogical and gold deportment properties, leaching mechanisms, and kinetic behaviour and pulp rheology, it was observed that the predominant cause of the poor extraction efficacy of one bio-oxidised product is the presence of recalcitrant sulphate minerals (e.g., jarosite and gypsum) produced during the oxidation process. This was followed by carbonaceous matter and other gangue minerals such as muscovite, quartz, and rutile. The underpining leaching mechanism and kinetics coupled with the pulp rheology were influenced by the feed mineralogy/chemistry, time, agitation/shear rate, interfacial chemistry, pH modifier type, and mechano-chemical activation. For instance, surface exposure of otherwise unavailable gold particles by mechano-chemical activation enhanced the gold leaching rate and yield. This work reflect the remarkable impact of subtle deposit feature changes on extraction performance.

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Shaw, C. S., C. Swinton, M. G. Morales-Scholz, N. McRae, T. Erftemeyer, A. Aldous, R. M. Murphy, and K. F. Howlett. "Impact of exercise training status on the fiber type-specific abundance of proteins regulating intramuscular lipid metabolism." Journal of Applied Physiology 128, no. 2 (February 1, 2020): 379–89. http://dx.doi.org/10.1152/japplphysiol.00797.2019.

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Endurance training enhances the capacity for fat oxidation during exercise due to increased utilization of intramuscular lipid (IMCL). This study quantitatively investigated the impact of exercise training status on muscle fiber type-specific abundance of regulatory proteins involved in IMCL utilization. Endurance-trained [ n = 7 subjects, peak oxygen consumption (V̇o2peak) 62.6 ± 4.1 (SD) mL·min−1·kg−1] and non-endurance-trained ( n = 8 subjects, V̇o2peak 44.9 ± 5.3 mL·min−1·kg−1) young men completed an incremental exercise test to determine maximal fat oxidation (MFO) and maximal oxygen uptake. Fiber type-specific IMCL content and protein abundance were assessed with immunofluorescence microscopy and immunoblot analysis of pooled single muscle fibers and whole muscle. Endurance-trained individuals displayed a higher MFO rate (0.45 ± 0.15 vs. 0.19 ± 0.07 g/min, P < 0.05), a greater proportion of type I muscle fibers, and higher IMCL content compared with untrained individuals ( P < 0.05). Adipose triglyceride lipase, hormone-sensitive lipase, perilipin 2, perilipin 5, and hydroxyacyl-coenzyme A dehydrogenase abundances were ~2–3-fold higher in type I muscle fibers compared with type IIa fibers ( P < 0.05). Correspondingly, these lipid proteins and oxidative enzymes were higher in endurance-trained individuals when assessed in whole muscle. MFO rate was strongly related to the proportion of type I fibers ( R = 0.81, P < 0.01). The abundance of proteins involved in the regulation of IMCL storage and oxidation is highly muscle fiber type specific. The increased capacity for fat oxidation in endurance-trained individuals corresponded with increased IMCL content and elevated abundance of lipolytic and oxidative enzymes in combination with a greater proportion of type I muscle fibers. NEW & NOTEWORTHY We have utilized contemporary techniques to compare the fiber type-specific characteristics of skeletal muscle from endurance-trained athletes and untrained individuals. We show that type I muscle fibers have a coordinated upregulation of proteins controlling intramuscular lipid storage, mobilization, and oxidation. Furthermore, the enhanced capacity for intramuscular lipid storage and utilization in endurance-trained individuals is related to the increased expression of lipid regulatory proteins combined with a greater proportion of type I muscle fibers.

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Sondergaard, Esben, Iben Rahbek, Lars P. Sørensen, Jens S. Christiansen, Lars C. Gormsen, Michael D. Jensen, and Søren Nielsen. "Effects of exercise on VLDL-triglyceride oxidation and turnover." American Journal of Physiology-Endocrinology and Metabolism 300, no. 5 (May 2011): E939—E944. http://dx.doi.org/10.1152/ajpendo.00031.2011.

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Lipids are important substrates for oxidation at rest and during exercise. Aerobic exercise mediates a delayed onset decrease in total and VLDL-triglyceride (TG) plasma concentration. However, the acute effects of exercise on VLDL-TG oxidation and turnover remain unclear. Here, we studied the acute effects of 90 min of moderate-intensity exercise in healthy women and men. VLDL-TG kinetics were assessed using a primed constant infusion of ex vivo labeled [1-14C]triolein VLDL-TG. Fractional VLDL-TG-derived fatty acid oxidation was measured from 14CO2 specific activity in expired air. VLDL-TG concentration was unaltered during exercise and early recovery, whereas non-VLDL-TG concentration decreased significantly.VLDL-TG secretion rate decreased significantly during exercise and remained suppressed during recovery. Total VLDL-TG oxidation rate was unaffected by exercise. However, the contribution of VLDL-TG oxidation to total energy expenditure fell from 14 ± 9% at rest to 3 ± 4% during exercise. We conclude that VLDL-TG fatty acids are quantitatively important oxidative substrates under basal postabsorptive conditions but remain unaffected during 90-min moderate-intensity exercise and, thus, become relatively less important during exercise. Lower VLDL secretion rate during exercise may contribute to the decrease in TG concentrations during and after exercise.

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KITAMURA, Keizo. "Measurement of Thermal Oxidation Rate for Various Deep-Fat Frying Oils by Specific Gravity." Journal of Japan Oil Chemists' Society 48, no. 3 (1999): 253–56. http://dx.doi.org/10.5650/jos1996.48.253.

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Janssen, Antoon JM, Frans JM Trijbels, Rob CA Sengers, Liesbeth TM Wintjes, Wim Ruitenbeek, Jan AM Smeitink, Eva Morava, Baziel GM van Engelen, Lambert P. van den Heuvel, and Richard JT Rodenburg. "Measurement of the Energy-Generating Capacity of Human Muscle Mitochondria: Diagnostic Procedure and Application to Human Pathology." Clinical Chemistry 52, no. 5 (May 1, 2006): 860–71. http://dx.doi.org/10.1373/clinchem.2005.062414.

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Abstract Background: Diagnosis of mitochondrial disorders usually requires a muscle biopsy to examine mitochondrial function. We describe our diagnostic procedure and results for 29 patients with mitochondrial disorders. Methods: Muscle biopsies were from 43 healthy individuals and 29 patients with defects in one of the oxidative phosphorylation (OXPHOS) complexes, the pyruvate dehydrogenase complex (PDHc), or the adenine nucleotide translocator (ANT). Homogenized muscle samples were used to determine the oxidation rates of radiolabeled pyruvate, malate, and succinate in the absence or presence of various acetyl Co-A donors and acceptors, as well as specific inhibitors of tricarboxylic acid cycle or OXPHOS enzymes. We determined the rate of ATP production from oxidation of pyruvate. Results: Each defect in the energy-generating system produced a specific combination of substrate oxidation impairments. PDHc deficiencies decreased substrate oxidation reactions containing pyruvate. Defects in complexes I, III, and IV decreased oxidation of pyruvate plus malate, with normal to mildly diminished oxidation of pyruvate plus carnitine. In complex V defects, pyruvate oxidation improved by addition of carbonyl cyanide 3-chlorophenyl hydrazone, whereas other oxidation rates were decreased. In most patients, ATP production was decreased. Conclusion: The proposed method can be successfully applied to the diagnosis of defects in PDHc, OXPHOS complexes, and ANT.

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Ekström, G., T. Cronholm, and M. Ingelman-Sundberg. "Hydroxyl-radical production and ethanol oxidation by liver microsomes isolated from ethanol-treated rats." Biochemical Journal 233, no. 3 (February 1, 1986): 755–61. http://dx.doi.org/10.1042/bj2330755.

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In order to distinguish between the mechanism of microsomal ethanol oxidation and hydroxyl-radical formation, the rate of cytochrome P-450 (P-450)-dependent oxidation of dimethyl sulphoxide (Me2SO) was determined in the presence and in the absence of iron-chelating compounds, in liver microsomes from control, ethanol- and phenobarbital-treated rats. Ethanol treatment resulted in a specific increase (3-fold) of the microsomal ethanol oxidation and NADPH consumption per nmol of P-450. A form of P-450 was purified to apparent homogeneity from the ethanol-treated rats and characterized with respect of amino acid composition and N-terminal amino acid sequence. Specific ethanol induction of a cytochrome P-450 species having a catalytic-centre activity of 20/min for ethanol and consuming 30 nmol of NADPH/min could account for the results observed with microsomes. Phenobarbital treatment caused 50% decrease in the rate of ethanol oxidation and NADPH oxidation per nmol of P-450. The rate of oxidation of the hydroxyl-radical scavenger Me2SO was increased 3-fold by ethanol or phenobarbital treatment when expressed on a per-mg-of-microsomal-protein basis, but the rate of Me2SO oxidation expressed on a per-nmol-of-P-450 basis was unchanged. Addition of iron-chelating agents to the three different types of microsomal preparations caused an ‘uncoupling’ of the electron-transport chain accompanied by a 4-fold increase of the rate of Me2SO oxidation. It is concluded that ethanol treatment results in the induction of P-450 forms specifically effective in ethanol oxidation and NADPH oxidation, but not in hydroxyl-radical production, as detected by the oxidation of Me2SO.

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Huang, Kai-Yu, Chih-Ta Wang, Wei-Lung Chou, and Chi-Min Shu. "Removal of Polyvinyl Alcohol in Aqueous Solutions Using an Innovative Paired Photoelectrochemical Oxidative System in a Divided Electrochemical Cell." International Journal of Photoenergy 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/623492.

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This study evaluates the performance of an innovative paired photoelectrochemical oxidative system fabricated in our laboratory to determine the removal efficiency of polyvinyl alcohol (PVA) in aqueous solutions. An innovative paired photoelectrochemical oxidative system employed metal redox mediators with high redox potential for anodic oxidation (MEO process) and UV assisted photoelectrochemical oxidation (PEO process) for cathodic oxidation in a divided electrochemical cell. Several parameters were investigated to characterize the removal efficiency of PVA, such as the current density, initial Ce(III) concentration, nitric acid concentration, oxygen flow rate, and UV irradiation intensity. The effects of these parameters on the specific energy consumption were also investigated. Additionally, the conversion yield of Ce(IV) concentration and the electrogeneration of H2O2were calculated in this study. The optimum current density, initial Ce(III) concentration, nitric acid concentration, oxygen flow rate, and UV irradiation intensity were found to be 3 mA cm−2, 0.01 M, 0.3 M, 500 cm3 min−1, and 1.2 mW cm−2, respectively. The synergistic effect of combination process of MEO and PEO would be as a promising alternative for the removal efficiency of PVA.

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Dasarathy, Srinivasan, Takhar Kasumov, John M. Edmison, Lourdes L. Gruca, Carole Bennett, Clarita Duenas, Susan Marczewski, Arthur J. McCullough, Richard W. Hanson, and Satish C. Kalhan. "Glycine and urea kinetics in nonalcoholic steatohepatitis in human: effect of intralipid infusion." American Journal of Physiology-Gastrointestinal and Liver Physiology 297, no. 3 (September 2009): G567—G575. http://dx.doi.org/10.1152/ajpgi.00042.2009.

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The rates of oxidation of glycine and ureagenesis were quantified in the basal state and in response to an intravenous infusion of intralipid with heparin (IL) in healthy subjects ( n = 8) and in subjects with nonalcoholic steatohepatitis (NASH) ( n = 6). During fasting, no significant difference in weight-specific rate of appearance ( Ra) of glycine, glycine oxidation, and urea synthesis was observed. Intralipid infusion resulted in a significant increase in plasma β-hydroxybutyrate in both groups. The correlation between free fatty acids and β-hydroxybutyrate concentration in plasma was 0.94 in NASH compared with 0.4 in controls, indicating greater hepatic fatty acid oxidation in NASH. Intralipid infusion resulted in a significant decrease in urea synthesis and glycine Rain both groups and did not impact glycine oxidation. The fractional contribution of glycine carbon to serine was lower in subjects with NASH before and after IL infusion. In contrast, the fractional contribution of serine carbon to cystathionine was higher in NASH before and following IL infusion. These results suggest that hepatic fatty acid oxidation is higher in NASH compared with controls and that glycine oxidation and urea synthesis are not altered. An increase in oxidative stress, induced by a higher rate of fatty acid oxidation in NASH, may have caused an increase in the contribution of serine to cystathionine to meet the higher demands for glutathione.

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Floc’h, Nathalie Le, Jean-noёl Thibault, and Bernard Sève. "Tissue localization of threonine oxidation in pigs." British Journal of Nutrition 77, no. 4 (April 1997): 593–603. http://dx.doi.org/10.1079/bjn19970059.

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Two experiments were designed to determine the tissue distribution of threonine oxidation through the threonine dehydrogenase (EC 1.1.1.103) pathway in pigs. The first experiment was conducted on eleven Piétrain x Large White piglets. The piglets were slaughtered at 5, 12 or 20 kg after 1 h of infusion with L-[U-14C]threonine (55 kBq/kg) mixed with unlabelled threonine (100 mg/kg). In the second experiment, four Piétrain x Large White and four Large White piglets (10 kg body weight) were infused with L-[1-13C]threonine (50 mg'kg) mixed with 50 mg'kg unlabelled threonine for 1 h, then killed for tissue sampling. In the two experiments, threonine dehydrogenase specific activity and threonine and glycine specific radioactivities and enrichments were measured in several tissues and in plasma. The higher level of labelling of threonine in the pancreas than in the liver suggested either a lower protein degradation rate or a faster rate of threonine transport in the liver than in the pancreas. Threonine dehydrogenase activity was found only in the liver and the pancreas. Whereas liver and pancreas threonine dehydrogenase specific activities were similar, glycine specific radioactivity and enrichment were 12- to 14-fold higher in the pancreas than in the liver. This is probably the consequence of a higher production rate of glycine from sources other than threonine (protein degradation, de novo synthesis from serine) in the liver than in the pancreas. Our results showed that Large White pigs could oxidize more threonine than Piétrain x Large White pigs. This could be related to the difference in growth performance and dietary N efficiency for protein deposition between these two genotypes.

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Houser, Dorian S., Daniel E. Crocker, Michael S. Tift, and Cory D. Champagne. "Glucose oxidation and nonoxidative glucose disposal during prolonged fasts of the northern elephant seal pup (Mirounga angustirostris)." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 303, no. 5 (September 1, 2012): R562—R570. http://dx.doi.org/10.1152/ajpregu.00101.2012.

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Elephant seal weanlings demonstrate rates of endogenous glucose production (EGP) during protracted fasts that are higher than predicted on the basis of mass and time fasting. To determine the nonoxidative and oxidative fate of endogenously synthesized glucose, substrate oxidation, metabolic rate, glycolysis, and EGP were measured in fasting weanlings. Eight weanlings were sampled at 14 days of fasting, and a separate group of nine weanlings was sampled at 49 days of fasting. Metabolic rate was determined via flow-through respirometry, and substrate-specific oxidation was determined from the respiratory quotient and urinary nitrogen measurements. The rate of glucose disposal (GluRd) was determined through a primed, constant infusion of [3-3H]glucose, and glycolysis was determined from the rate of appearance of 3H in the body water pool. GluRd was 1.41 ± 0.27 and 0.95 ± 0.21 mmol/min in the early and late fasting groups, respectively. Nearly all EGP went through glycolysis, but the percentage of GluRd oxidized to meet the daily metabolic demand was only 24.1 ± 4.4% and 16.7 ± 5.9% between the early and late fasting groups. Glucose oxidation was consistently less than 10% of the metabolic rate in both groups. This suggests that high rates of EGP do not support substrate provisions for glucose-demanding tissues. It is hypothesized that rates of EGP may be ancillary to the upregulation of the tricarboxylic acid cycle to meet high rates of lipid oxidation while mitigating ketosis.

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Jeyanthi, Fatima, G. Vijayakiiinarand, and K. P. Elango. "The effect of solvent on the kinetics of the oxidation of benzaldehydes by quinolinium chlorochromate in aqueous organic solvent media." Journal of the Serbian Chemical Society 67, no. 12 (2002): 803–8. http://dx.doi.org/10.2298/jsc0212803j.

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The kinetics of the oxidation of benzaldehyde and para-substituted benzaldehydes by quinolinium chlorochromate in water-dimethylformamide mixtures has been studied under pseudo-first-order conditions at 25?0.2?C. The operation of non-specific and specific solvent-solute interactions was explored by correlating the rate data with solvent parameters through a correlation analysis technique. Both electron-releasing and electron-withdrawing substitutents enhance the rate of oxidation and the Hammett plot shows a break in the reactivity order indicating the applicability of a dual mechanism.

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Ruhma, Zaka, Asep Ridwan Setiawan, Aditianto Ramelan, and Rochim Suratman. "Effect of Ti Addition on Oxidation Behavior and Area Specific Resistance of Fe-20Cr Alloys for SOFC Interconnects." Applied Mechanics and Materials 660 (October 2014): 249–53. http://dx.doi.org/10.4028/www.scientific.net/amm.660.249.

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In this work, the oxidation behavior of Fe-20wt.%Cr alloys with different titanium contents: 0, 0.5, and 1 wt.% are studied as a function of time in air atmosphere. The samples were isothermally oxidized at 700°C for 24, 48, and 96 h in a box furnace. The area specific resistance of oxides formed at the alloys surface during oxidation is measured by four-point probe methods at 700°C for 24 h. For Ti containing alloys, surface morphology observation by SEM shows that a few of TiO2 particles formed on the top of Cr2O3 scales. Continous TiO2 layer was not formed at the alloys surface after oxidation. XRD analysis on the oxide scales of Fe-20Cr-Ti alloys confirms that Cr2O3 and TiO2 oxide formed on the alloys. Ti addition into the alloys increases the oxidation rates of alloys at the initial stages. Oxidation behavior of Fe-20Cr-0.5Ti and Fe-20Cr-1Ti alloys showed two regimes. The parabolic rate constant, kp (in gr2/cm4s) were 1.57 x 10-13 and 3.08 x 10-13 respectively for initial stage of oxidation then changed to-9 x 10-15 and-3 x 10-14 respectively for the remainder of the test. ASR measurement shows that the presence of Ti in the alloys decreases the electrical resistance up to 60%. Ti addition into Fe-Cr alloys affect the oxide growth rate and increase the conductivity of Cr2O3 scales.

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Vazquez, J. A., H. S. Paul, and S. A. Adibi. "Relation between plasma and tissue parameters of leucine metabolism in fed and starved rats." American Journal of Physiology-Endocrinology and Metabolism 250, no. 6 (June 1, 1986): E615—E621. http://dx.doi.org/10.1152/ajpendo.1986.250.6.e615.

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By use of a primed continuous infusion of [1-14C]leucine, we investigated parameters of leucine metabolism in plasma, expired air, and tissues of fed and 48-h starved rats. The ratios of muscle to plasma specific activity of alpha-ketoisocaproate (KIC) in fed and starved rats were not significantly different from 1. The ratio of muscle to plasma specific activity of leucine was also not significantly different from 1 in fed rats, but was significantly lower than 1 in starved rats. The rate of leucine oxidation was 28-34% higher when calculation was based on plasma KIC rather than leucine specific activity. However, starvation significantly increased the rate of leucine oxidation with either specific activity. The rates of leucine incorporation into whole-body protein, calculated as the difference between plasma leucine turnover and oxidation, were unaffected by starvation, but the incorporations into total protein measured directly were significantly decreased in liver and muscle. We conclude that leucine or KIC specific activity in muscle is better predicted by plasma KIC than leucine specific activity, and the difference between rates of plasma leucine turnover and oxidation does not appear to be a valid measurement of leucine incorporation into whole-body protein.

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Henderson, S. A., A. L. Black, and G. A. Brooks. "Leucine turnover and oxidation in trained rats during exercise." American Journal of Physiology-Endocrinology and Metabolism 249, no. 2 (August 1, 1985): E137—E144. http://dx.doi.org/10.1152/ajpendo.1985.249.2.e137.

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The effects of training on leucine turnover and oxidation were studied during rest and exercise in young, postabsorptive female rats. Relationships were primarily studied by the continuous infusion method, using [1-14C]leucine. Arterial blood was assayed for leucine specific activity and expired air was monitored for O2 consumption, CO2 production, and the specific activity of 14CO2. The rate of leucine turnover in trained rats was 70% greater than the rate of leucine turnover in untrained rats and was not affected by exercise. By virtue of a higher turnover, the rate of leucine oxidation was 40% greater in trained rats during both rest and exercise. Moreover, leucine oxidation was proportional to the metabolic rate and represented 30% of the leucine turnover at rest and 40-60% of the leucine turnover during exercise. In the same animals leucine turnover was secondarily assessed by measuring the fraction of the [1-14C]leucine dose contained in the hemoglobin pool 4 wk after infusion (occupancy tracer method). Occupancy values for leucine turnover were not different from those determined by the continuous infusion method. The results show that whole body leucine turnover is increased by training and that leucine oxidation is increased by both training and exercise.

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Balela, Mary Donnabelle L., Thomas Jay E. Angostura, Amiel Marc F. Domingo, and Charmaine Grace P. Facal. "Two-Step Synthesis of Cobalt Oxide Nanowires via Electroless Deposition and Thermal Oxidation for Supercapacitor Applications." Key Engineering Materials 775 (August 2018): 336–41. http://dx.doi.org/10.4028/www.scientific.net/kem.775.336.

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Cobalt (Co) nanowires were synthesized via electroless deposition in ethylene glycol under an external magnetic field then oxidized in air via thermal oxidation at 250 to 300 °C. The nanowires have lengths in the range of 10 to 14 µm while the diameter increases with oxidation temperature. This can be attributed to the partial melting of the nanowires during oxidation, resulting to sintering. The peaks in the XRD patterns show complete oxidation of Co nanowires, producing a mixture of Co3O4 and CoO. It was observed that Co3O4 and CoO peaks were more intense at 270 °C. There is a decrease in specific capacitance (F/g) with increase in scan rate due to poor electron exchange between active material electrode and electrolyte. Highest calculated specific capacitance was 339.28 F/g using nanowires oxidized at 270 °C at 1 mV/s scan rate.

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Vind, C., A. Hunding, and N. Grunnet. "Pathways of reducing equivalents in hepatocytes from rats. Estimation of cytosolic fluxes by means of 3H-labelled substrates for either A- or B-specific dehydrogenases." Biochemical Journal 243, no. 3 (May 1, 1987): 625–30. http://dx.doi.org/10.1042/bj2430625.

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The metabolism of [2-3H]lactate and [2-3H]glycerol was studied in isolated hepatocytes from fed rats. In order to estimate the rate of equilibrium between the 4A and 4B hydrogen atoms of NADH, we compared the flow of 3H from [2-3H]lactate and [2-3H]glycerol, the oxidations of which are catalysed by A- and B-type dehydrogenases, respectively. Hepatocytes were incubated with lactate, glycerol and ethanol and tracer amounts of [2-3H]lactate or [2-3H]glycerol and the labelling rates of lactate, ethanol, glucose and glycerol phosphate were determined. The data were used to calculate the oxidation rate of NADH catalysed by lactate dehydrogenase, alcohol dehydrogenase, triosephosphate dehydrogenase and glycerol phosphate dehydrogenase. The rates were calculated by obtaining the best fit of a model to the experimental data by using a least-squares procedure. The results support our model and suggest that the fluxes through various dehydrogenases are sufficient to equilibrate the 4A and 4B hydrogen atoms of cytosolic NADH. The validity of the metabolic models used was evaluated by comparison of rates of NADH oxidation catalysed by cytosolic dehydrogenases as calculated by two different models.

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Maree, J. P., D. Dingemans, G. J. van Tonder, and S. Mtimkulu. "Biological iron(II) oxidation as pre-treatment to limestone neutralisation of acid water." Water Science and Technology 38, no. 4-5 (August 1, 1998): 331–37. http://dx.doi.org/10.2166/wst.1998.0658.

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Iron(II) should be oxidised to iron(III) before the neutralisation of acid water with limestone, otherwise the oxidation will occur downstream of the neutralisation plant with the formation of acid (reactions 1 and 2). This study aimed at investigating the effect of surface area of the medium that supports bacterial growth on the rate of biological iron(II) oxidation. The study showed that the biological iron(II) oxidation rate is directly proportional to the square root of the medium specific surface area.

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Belyi, A. V., Tamara F. Kondrat'eva, Aleksander Bulaev, N. V. Solopova, N. V. Grigor’eva, M. I. Murav’yov, A. E. Panyushkina, and I. A. Tsaplina. "Neutrophilic Microbial Community with High Rate of Elemental Sulfur Oxidation." Advanced Materials Research 1130 (November 2015): 59–62. http://dx.doi.org/10.4028/www.scientific.net/amr.1130.59.

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Using molecular genetic methods, 10 species wereidentified in the community of neutrophilic microorganisms isolated from thebioreactor during the process of biooxidation of gold-arsenicpyrrhotite-bearing sulfide ore flotation concentrate. The microbial communitywas composed of chemolithotrophs oxidizing elemental sulfur and its reducedcompounds and chemoorganotrophs. The predominant S0-oxidizingchemolithotrophic strain and 3 strains of chemoorganotrophs were isolated inpure cultures. Phylogenetic identification of the pure cultures revealed thechemolithotrophic microorganism to belong to Thermithiobacillus tepidarius,while organotrophic microorganisms were identified as Parapedobacter sp.,Nocardioides nitrophenolicus, and Nocardioides sp. Themorphological and physiological characteristics of Thermithiobacillustepidarius and Nocardioides nitrophenolicus, the culturespredominant in the community of neutrophilic microorganisms, were studied.Active growth of T. tepidarius occurs within a temperature range of38–48°C at the optimal pH value of 7.0–7.5. The maximal specific growth rate ofT. tepidarius on sulfur and on solid residue which remains after theprocess of bioleaching/biooxidation of sulfide ore flotation concentrate (biooxidationresidue) was 0.13 and 0.135 h-1, respectively. The average maximalrate of S0 oxidation in the biooxidation residue was 0.107 g S0oxidizedper g S0initial h-1. The ability of Nocardioidesnitrophenolicus to destruct thiocyanate was shown.

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24

Panov, A. V., and R. C. Scaduto. "Substrate specific effects of calcium on metabolism of rat heart mitochondria." American Journal of Physiology-Heart and Circulatory Physiology 270, no. 4 (April 1, 1996): H1398—H1406. http://dx.doi.org/10.1152/ajpheart.1996.270.4.h1398.

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Oxidative metabolism in the heart is tightly coupled to mechanical work. Because this coupling process is believed to involve Ca2+, the roles of mitochondrial Ca2+ in the regulation of oxidative phosphorylation was studied in isolated rat heart mitochondria. The electrical component of the mitochondrial membrane potential (delta psi) and the redox state of the pyridine nucleotides were determined during the oxidation of various substrates under different metabolic states. In the absence of added adenine nucleotides, the NADP+ redox couple was almost completely reduced, regardless of the specific substrate and the presence of Ca2+, whereas NAD+ couple redox state was highly dependent on the substrate type and the presence of Ca2+. Titration of respiration with ADP, in the presence of excess hexokinase and glucose, showed that both respiration and NAD(P)+ reduction were very sensitive to ADP. The maximal enzyme reaction rate of ADP-stimulated respiration Michaelis constants (Km) for ADP were dependent on the particular substrate employed. delta psi was much less sensitive to ADP. With either alpha-ketoglutarate or glutamate as substrate, Ca2+ significantly increased reduction of NAD(P)+.Ca2+ did not influence NAD(P)+ reduction with either acetylcarnitine or pyruvate as substrate. In the presence of ADP, delta psi was increased by Ca2+ at all metabolic states with glutamate plus malate, 0.5 mM alpha-ketoglutarate plus malate, or pyruvate plus malate as substrates. The data presented support the hypothesis that cardiac respiration is controlled by the availability of both Ca2+ and ADP to mitochondria. The data indicate that an increase in substrate supply to mitochondria can increase mitochondrial respiration at given level of ADP. This effect can be produced by Ca2+ with substrates such as glutamate, which utilize alpha-ketoglutarate dehydrogenase activity for oxidation. Increases in respiration by Ca2+ may mitigate an increase in ADP during periods of increased cardiac work.

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25

Pilip, Larisa V., Olga V. Byakova, and Maria E. Kazakova. "Specific features of biological oxidation processes in helminthiases of horses." Butlerov Communications 61, no. 3 (March 31, 2020): 126–30. http://dx.doi.org/10.37952/roi-jbc-01/20-61-3-126.

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The chemical processes occurring in the animal body under pathological conditions are of interest to researchers. The objective of the research was to study the indicators of lipid peroxidation and antioxidant activity in horses infested with helminthiases and treated with anthelmintic paste with an antioxidant. The study has proved the role of parasitic infestation in accelerating the processes of free radical oxidation, which is manifested by a decrease in the light sum of radicals (36.62-39.21), the maximum luminous intensity (6.13-6.98) and antioxidant activity (5.65-6.2) at the start of the research. Chronic invasion increases the concentration of under-oxidized products up to 38.59, and the rate of initiating free radical oxidation – up to 6.95, the values of antioxidant activity being stably low (5.51-5.91). An important role in the regulation of lipid peroxidation in horses during helminthiases, as well as in the process of deworming, is played by the antioxidants contained in anthelmintic preparations. The antioxidant santohin included as a compound in the «Alezan» preparation suppresses enhanced peroxidation and activates the antioxidant protection of the body, which is reflected in a decrease in the light sum of the radicals to as low as 26.73, a maximum luminous intensity to – 3.76, and an increase in antioxidant activity – up to 7.16.

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26

Schroedl, N. A., V. L. Funanage, C. R. Bacon, S. M. Smith, and C. R. Hartzell. "Hemin increases aerobic capacity of cultured regenerating skeletal myotubes." American Journal of Physiology-Cell Physiology 255, no. 4 (October 1, 1988): C519—C525. http://dx.doi.org/10.1152/ajpcell.1988.255.4.c519.

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Regeneration of damaged, mature muscle occurs by differentiation of satellite cells. In culture, satellite cell myoblasts proliferate, align, and fuse to form cross-striated, contracting myotubes. The biochemical changes and the factors that regulate differentiation in satellite cells have not been investigated previously. We report here that no significant differences in glucose uptake rate or glucose oxidation rate were observed between regenerating myoblasts and myotubes, whereas the aerobic oxidation of palmitic acid increased 7.3-fold between these differentiation states. Specific activities of enzymes of critical importance in aerobic metabolism or in production of ATP were increased 2- to 3.5-fold during fusion. Addition of 20 microM hemin to regenerating muscle cultures potentiated the aerobic capacity as evidenced by a 23.6% increase in palmitate oxidation rate. Hemin also increased the specific activities of all nonheme enzymes investigated with the exception of phosphofructokinase. This augmentation of aerobic metabolism together with the time frame of active muscle differentiation suggests a complex role for hemin in myogenesis.

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27

Meena, V. K., and H. R. Ghatak. "Electrochemical Mineralization Kinetics of Metformin." Asian Journal of Chemistry 34, no. 3 (2022): 727–32. http://dx.doi.org/10.14233/ajchem.2022.23618.

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Present work analyzes the kinetic study of mineralization during electro-oxidation on Ti/DSA (Ta2O5-Ir2O5) and combined electro-oxidation and electro-coagulation on stainless steel anode of an antidiabetic drug metformin hydrochloride (MET-HCl) in synthetic wastewater over a specific charge. Four different reaction orders (0.5, 1, 1.5 and 2) were tested using the integral analysis method by plotting TOC concentration terms over specific charges to determine the exact rate kinetics for the mineralization. The effect of applied current density was evaluated at 50 ppm of sodium sulphate as supporting electrolyte, and the effect of supporting electrolyte concentration was also assessed at a current density of 0.93 mA/cm2 in 50 ppm MET-HCl solution. As a result of (i) electro-oxidation experiments on MET-HCl, carried out on Ti/DSA anode, and (ii) combined electro-oxidation and electro-coagulation experiments carried out on stainless steel anode, based on the R-squared value of the mineralization curves, the first-order reaction rate was proposed.

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28

Jiang, Yu Ze, Jiu Tao An, Di Wen Jiang, Jie Li, and Yan Wu. "Oxidation of Elemental Mercury by Active Species Injection from a Surface Discharge Reactor." Advanced Materials Research 807-809 (September 2013): 1294–97. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.1294.

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Active species injection generated by a surface discharge plasma reactor (SDPR) was studied to oxidize elemental mercury (Hg0) in the flue gas. The reactor was inserted in the simulated flue duct. The effects of several operational parameters, such as applied voltage, inlet Hg0 concentration, applied frequency and air injection flow rate, were well investigated. Experimental results showed that Hg0 oxidation efficiency of 83.8% was achieved at specific energy density of 4.0 J L-1 and the flow rate of 1.6 L min-1. Increasing applied voltage and air injection flow rate was beneficial for Hg0 oxidation due to higher production of active species. Lower Hg0 oxidation efficiency was observed with an increase of initial concentration. With an increase of applied frequency, Hg0 oxidation efficiency significantly increased, but the energy yield dropped.

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29

Mansell, P. I., and I. A. Macdonald. "Reappraisal of the Weir equation for calculation of metabolic rate." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 258, no. 6 (June 1, 1990): R1347—R1354. http://dx.doi.org/10.1152/ajpregu.1990.258.6.r1347.

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In 1949 Weir (3) demonstrated that the metabolic rate calculated from respiratory gas exchange measurements is to a close approximation proportional to the difference in percentage oxygen content between inspired and expired air. Although values for the energy equivalent of oxygen consumed and for the respiratory quotient for the oxidation of various nutrients have been revised since 1949, we show that the error in the calculation remains generally below 0.5% for the oxidation of dietary carbohydrate, fat, and protein. Where the original equation is uncritically applied to situations in which other nutrients are being oxidized, the error may reach 3%, although alternative methods for calculating the metabolic rate may be similarly in error. We give the derivation from first principles of the general mathematical solution to the calculation of the metabolic rate following Weir's method. Examples are provided of the subsequent derivation of specific equations for the more precise calculation of the metabolic rate where different combinations of nutrients are being oxidized.

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30

Tribble, Diane L., Berbie M. Chu, Gerri A. Levine, Ronald M. Krauss, and Elaine L. Gong. "Selective Resistance of LDL Core Lipids to Iron-Mediated Oxidation." Arteriosclerosis, Thrombosis, and Vascular Biology 16, no. 12 (December 1996): 1580–87. http://dx.doi.org/10.1161/01.atv.16.12.1580.

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Although the nature and consequences of oxidative changes in the chemical constituents of low density lipoproteins (LDLs) have been extensively examined, the physical dynamics of LDL oxidation and the influence of physical organization on the biological effects of oxidized LDLs have remained relatively unexplored. To address these issues, in the present studies we monitored surface- and core-specific peroxidative stress relative to temporal changes in conjugated dienes (CDs), particle charge (an index of oxidative protein modification), and LDL-macrophage interactions. Peroxidative stress in LDL surface and core compartments was evaluated with the site-specific, oxidation-labile fluorescent probes parinaric acid (PnA) and PnA cholesteryl ester (PnCE), respectively. When oxidation was initiated by Cu 2+ , oxidative loss of the core probe (PnCE) closely followed that of the surface probe (PnA), as indicated by the time to 50% probe depletion (t 1/2 ; 15.5±7.8 and 30.4±12 minutes for PnA and PnCE, respectively). Both probes were more resistant in LDL exposed to Fe 3+ (t 1/2 , 53.2±8.1 and 346.7±155.4 minutes), although core probe resistance was much greater with this oxidant (PnCE t 1/2 /PnA t 1/2, 5.8 vs 2.0 for Cu 2+ ). Despite differences in the rate and extent of oxidative changes in Cu 2+ - versus Fe 3+ -exposed LDLs, PnCE loss occurred in close correspondence with CD formation and appeared to precede changes in particle charge under both conditions. Exposure of LDLs to hemin, a lipophilic Fe 3+ -containing porphyrin that becomes incorporated into the LDL particle, resulted in rapid loss of PnCE and simultaneous changes in particle charge, even at concentrations that yielded increases in CDs and thiobarbituric acid–reactive substances similar to those obtained with free Fe 3+ . These results suggest that oxidation of the LDL hydrophobic core occurs in conjunction with accelerated formation of CDs and may be essential for LDL protein modification. In accordance with the known effects of oxidative protein modifications on LDL receptor recognition, exposure of LDLs to Cu 2+ and hemin but not Fe 3+ produced particles that were readily processed by macrophages. Thus, the physical site of oxidative injury appears to be a critical determinant of the chemical and biological properties of LDLs, particularly when oxidized by Fe 3+ .

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31

Ma, Jing, Guotong Qin, Wei Wei, Tianliang Xiao, Shaomin Liu, and Lei Jiang. "Anti-corrosion porous RuO2/NbC anodes for the electrochemical oxidation of phenol." RSC Advances 9, no. 30 (2019): 17373–81. http://dx.doi.org/10.1039/c9ra03353j.

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32

Wang, Jing, Jian An Hao, Ai Jun Zhang, Bo Yang, Tian Xiang Jiang, Xiu Zhi Zhang, Xiao Qing Zhang, and Yu Shan Zhang. "Startup of Seawater Anaerobic Ammonia Oxidation Reactor." Advanced Materials Research 884-885 (January 2014): 582–85. http://dx.doi.org/10.4028/www.scientific.net/amr.884-885.582.

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Muds and water samples collected from the Bohai Sea were selected to build seawater anaerobic ammonia oxidation reactor. The reaction volume was 18 L. The startup of reactor was divided into two stages. The first stage lasted five months and hydraulic retention time was 18L/7 d. The second stage lasted a month and hydraulic retention time was 18L/14 d. Ammonia and nitrite of influent and effluent were monitored. During the first stage, the removal rate of ammonia nitrogen was around 50% and the nitrite nitrogen increased by 50%. During the second stage, the removal rate of ammonia nitrogen reached more than 75% and the removal rate of nitrite nitrogen reached more than 90%. The removal ratio of ammonia nitrogen and nitrate nitrogen was about 1:1.17. These results suggested reactor start-up successful. Microbial community in reactor was monitored by polymerase chain reaction. Once the reactor started, specific bands of anaerobic ammonia oxidation microorganisms were found.

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33

Fux, C., V. Marchesi, I. Brunner, and H. Siegrist. "Anaerobic ammonium oxidation of ammonium-rich waste streams in fixed-bed reactors." Water Science and Technology 49, no. 11-12 (June 1, 2004): 77–82. http://dx.doi.org/10.2166/wst.2004.0809.

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The feasibility of anaerobic ammonium oxidation (Anammox) in fixed-bed reactors was evaluated on laboratory and pilot scales. Using synthetic wastewater, the specific nitrogen removal rate was increased from 0.05-0.1 kgNm-3reactord-1 to 0.35-0.38 kgNm-3reactord-1 within a year (T = 22-27°C) in all applications. However, the anammox activity was seriously and repeatedly inhibited at prolonged high nitrite concentrations (e.g. six days at 30-50 gNO2-Nm-3) and recovery was always a lengthy process. But even at a moderate nitrite concentration (11 ± 10 gNO2-Nm-3), the observed specific growth rate was only 0.018 d-1 at 26.4 ± 0.8°C, which corresponds to approximately 0.025 d-1 at 30°C (doubling time: 28 days). In a second experimental period for another 250 days, one of the laboratory reactors was fed with partially nitrified sludge liquors from a domestic wastewater treatment plant (WWTP). In this case, the specific elimination rate was as high as 3.5 kgNm-3reactord-1 at 26-27°C. Independently of the feed, the average nitrogen elimination rate lay between 80-85% in all applications. An appropriate hydraulic design is essential to prevent clogging and local nitrite inhibition in fixed-bed reactors.

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34

Boxall, Naomi J., Ka Yu Cheng, Chris A. du Plessis, David Collinson, Christina Morris, Natalia Streltsova, Brigitte Seaman, David Seaman, Luke Vollert, and Anna H. Kaksonen. "Increasing cell concentration does not affect specific ferrous iron oxidation rate in a continuously stirred tank bioreactor." Hydrometallurgy 181 (November 2018): 189–94. http://dx.doi.org/10.1016/j.hydromet.2018.09.008.

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35

Borma, Laura De Simone, Maurício Ehrlich, and Maria Cláudia Barbosa. "Acidification and release of heavy metals in dredged sediments." Canadian Geotechnical Journal 40, no. 6 (December 1, 2003): 1154–63. http://dx.doi.org/10.1139/t03-062.

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The oxidation of iron sulphides in dredged sediments can be a source of long-term contamination of surface and underground water. The adverse effects are related to a decrease in the ability of soil to retain heavy metals, which is caused by acidification. Laboratory tests were conducted, and pH variations and consequent release of heavy metals, especially Zn, Cu, and Pb, into the solution were monitored over time. The rate of pyrite oxidation was determined based on the sulphate production rate, through the stoichiometry of the oxidation reaction. Samples of sediments from the Jacarepaguá lagoon complex, State of Rio de Janeiro, were dried and oxidized over a period of 10 months. During this period the pH fell from 6.9 to 3.3, with oxidation of approximately 20% of the sulphur present in the form of iron sulphide, and 45% of the Zn, 15% of the Pb, and 5% of the Cu contained in the material were released. The oxidation rate at the initial stages was of the order of 1.0 × 104 g(O2)·h1, decreasing to 1.0 × 105 g(O2)·h1 during the test. This study presents the laboratory methodology developed for determining the oxidation rate in a system where the oxygen consumption is governed not only by the pyrite oxidation, but also by the organic matter. In these experiments, a key measure of intrinsic oxidation rate (IOR) is the oxidation rate where oxygen is freely available at normal atmospheric concentration. By comparing the values obtained for the dredged material with the results of the IOR of mining waste materials reported in the literature, it was observed that the oxidation rates of the iron sulphide formed in the Jacarepaguá lagoon environment were one to two orders of magnitude higher than those of mineral iron sulphides from coal wastes. This behavior can be explained considering that the iron sulphides in dredged materials are freshly formed and have more specific surface area exposed to air than the iron sulphide mineral in mining wastes.Key words: sediments, dredging, sulphides, oxidation, acidification, heavy metals.

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36

Gao, Yuan, Jin Chuan Jie, Peng Chao Zhang, Jian Zhang, Tong Min Wang, and Ting Ju Li. "Investigation of the Wear Behavior of High Strength and High Conductivity Cu-Cr-Zr Alloy under Dry Sliding." Materials Science Forum 817 (April 2015): 661–66. http://dx.doi.org/10.4028/www.scientific.net/msf.817.661.

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The dry sliding wear behavior of Cu-Cr-Zr alloy prepared by electromagnetic horizontal continuous casting was investigated. The wear behavior of the studied alloy was discussed in terms of friction coefficient, mass loss/sliding, specific wear rate and wear mechanism. The results indicate that with the increasing normal load and sliding velocity, the friction coefficient of Cu-Cr-Zr alloy decreased monotonically, the mass loss/sliding and specific wear rate increased. By wear surface morphology and composition analysis, the wear mechanisms were discussed preliminary. Oxidation and abrasion mechanisms dominated at the lower sliding velocities and loads. Increasing loads and velocities led to a combination of oxidation and adhesion. Plastic deformation was dominant for the higher applied load and sliding velocities.

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37

Araki, Hiroyuki, Kenichi Koga, Katsuto Inomae, Tetsuya Kusuda, and Youichi Awaya. "Intermittent Aeration for Nitrogen Removal in Small Oxidation Ditches." Water Science and Technology 22, no. 3-4 (March 1, 1990): 131–38. http://dx.doi.org/10.2166/wst.1990.0193.

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An intermittent aeration method is available for nitrogen removal in a small oxidation ditch. The purpose of this study is to establish a basis for design and operation of the oxidation ditch with the intermittent aeration method. Discussions on the essential process parameters depending on cycle time tc, aerobic period ta, specific nitrification rate vn and specific denitrification rate vd were carried out by using a continuous-flow stirred-tank model. It is shown theoretically that an optimum range of the aerobic time ratio (ta/tc) for nitrogen removal exists in the region of 1/v n* to 1-1/vd*. From evaluating an amount of leaking nitrogen in the intermittent aeration, the cycle time is proved to be minimized. Experiments in a full scale test plant were conducted to affirm the validity of the proposed basis. It is confirmed that the total nitrogen removal efficiency of 90% is achieved and the estimated removal efficiencies by this basis agree well with the experimental data. The newly proposed basis and parameters for nitrogen removal using the intermittent aeration method are available for not only an oxidation ditch but also other nitrogen removal processes by single sludge systems.

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38

Maree, J. P., W. F. Strydom, and M. de Beer. "Integrated iron(II) oxidation and limestone neutralisation of acid mine water." Water Science and Technology 39, no. 10-11 (May 1, 1999): 231–38. http://dx.doi.org/10.2166/wst.1999.0662.

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Volumetric iron(II) oxidation rates exceeding 100 g/(l.d) were achieved by dosing powdered limestone to a bio-reactor treating artificial acid mine water. Neutralisation and partial sulphate removal were achieved as well. The rate is highly dependent on the surface area exposed to the liquid (RSA) and the OH−, oxygen, CaCO3, suspended solids and iron(II) concentrations, and less dependent on specific surface area (SSA) and pressure in the pH range 5 to 6. The chemical oxidation rate (pH greater than 6) is dependent on the OH−, oxygen, and iron(II) concentrations and the reactor surface area (RSA).

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39

Kladeková, Daniela, Alexander Hanudeľ, Milan Brutovský, and Ján Novák. "Oxidation of Butane to Maleic Anhydride on Unmodified and Modified Vanadium-Phosphorus Catalysts." Collection of Czechoslovak Chemical Communications 60, no. 3 (1995): 457–63. http://dx.doi.org/10.1135/cccc19950457.

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Properties of modified vanadium-phosphorus catalysts were studied and compared with the unmodified catalyst in the oxidation of butane. The highest promoting effect has been achieved by introducing cobalt to the catalyst lattice. At 90% conversion, the yield of maleic anhydride amounted to 59 mole per cent. The catalyst modified by cobalt increased the specific rate of butane oxidation and maleic anhydride formation three times compared to the unmodified catalyst. The specific activity of the catalysts decreased in the following order: Co > U ~ Ce > V-P-O > K ~ Mo.

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40

Xie, Fan, Pieter De Wever, Pedro Fardim, and Guy Van den Mooter. "TEMPO-Oxidized Cellulose Beads as Potential pH-Responsive Carriers for Site-Specific Drug Delivery in the Gastrointestinal Tract." Molecules 26, no. 4 (February 15, 2021): 1030. http://dx.doi.org/10.3390/molecules26041030.

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The development of controlled drug delivery systems based on bio-renewable materials is an emerging strategy. In this work, a controlled drug delivery system based on mesoporous oxidized cellulose beads (OCBs) was successfully developed by a facile and green method. The introduction of the carboxyl groups mediated by the TEMPO(2,2,6,6-tetramethylpiperidine-1-oxyradical)/NaClO/NaClO2 system presents the pH-responsive ability to cellulose beads, which can retain the drug in beads at pH = 1.2 and release at pH = 7.0. The release rate can be controlled by simply adjusting the degree of oxidation to achieve drug release at different locations and periods. A higher degree of oxidation corresponds to a faster release rate, which is attributed to a higher degree of re-swelling and higher hydrophilicity of OCBs. The zero-order release kinetics of the model drugs from the OCBs suggested a constant drug release rate, which is conducive to maintaining blood drug concentration, reducing side effects and administration frequency. At the same time, the effects of different model drugs and different drug-loading solvents on the release behavior and the physical state of the drugs loaded in the beads were studied. In summary, the pH-responsive oxidized cellulose beads with good biocompatibility, low cost, and adjustable release rate have shown great potential in the field of controlled drug release.

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41

Panov, Yevgen, Nikolai Gomelia, Olena Ivanenko, Andrii Vahin, and Serhii Leleka. "Determination of the Conditions for Carbon Materials Oxidation with Carbon Monoxide Formation at High Temperatures." Chemistry & Chemical Technology 14, no. 4 (December 15, 2020): 545–52. http://dx.doi.org/10.23939/chcht14.04.545.

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In this paper, the influence of carbon material type, temperature and oxygen concentration in gas mixture on the processes of carbon monoxide formation in production of the electrodes by graphitization was explored experimentally. Specific quantity of gas formed for a definite time, reduced to mass unit of carbon loading using pitch, packing materials and charge mixture of industrial use, was calculated. It is demonstrated that pitch provides the highest rate of carbon oxidation with the release of CO and substantially exceeds packing materials and charge mixture for this index.

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42

Savic, Dragisa, Miodrag Lazic, Vlada Veljkovic, and Miroslav Vrvic. "Pyrite oxidation by Acidithiobacillus ferrooxidans bacteria." Chemical Industry 59, no. 1-2 (2005): 15–18. http://dx.doi.org/10.2298/hemind0502015s.

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The kinetic model of pyrite particle dissolution by the action of bacteria Acidithiobacillus ferrooxidans in a shaken Erlenmeyer flask was presented. The model agreed well with the experimental data for the extracted iron and the number of cells in the liquid phase. The specific growth rate of the adsorbed cells was evaluated (?A = 1,6 d-1) by fitting the experimental data to the model curve. Also, the relevance of the two proposed mechanisms for the bacterial dissolution of sulphide (direct and indirect) was discussed, indicating that the indirect one was dominant. The adsorption process of A. ferrooxidans to the pyrite surface was well correlated by a Langmuir type isotherm.

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43

Stanley, William C., Eric E. Morgan, Hazel Huang, Tracy A. McElfresh, Joseph P. Sterk, Isidore C. Okere, Margaret P. Chandler, Jiefei Cheng, Jason R. B. Dyck, and Gary D. Lopaschuk. "Malonyl-CoA decarboxylase inhibition suppresses fatty acid oxidation and reduces lactate production during demand-induced ischemia." American Journal of Physiology-Heart and Circulatory Physiology 289, no. 6 (December 2005): H2304—H2309. http://dx.doi.org/10.1152/ajpheart.00599.2005.

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The rate of cardiac fatty acid oxidation is regulated by the activity of carnitine palmitoyltransferase-I (CPT-I), which is inhibited by malonyl-CoA. We tested the hypothesis that the activity of the enzyme responsible for malonyl-CoA degradation, malonyl-CoA decarboxlyase (MCD), regulates myocardial malonyl-CoA content and the rate of fatty acid oxidation during demand-induced ischemia in vivo. The myocardial content of malonyl-CoA was increased in anesthetized pigs using a specific inhibitor of MCD (CBM-301106), which we hypothesized would result in inhibition of CPT-I, reduction in fatty acid oxidation, a reciprocal activation of glucose oxidation, and diminished lactate production during demand-induced ischemia. Under normal-flow conditions, treatment with the MCD inhibitor significantly reduced oxidation of exogenous fatty acids by 82%, shifted the relationship between arterial fatty acids and fatty acid oxidation downward, and increased glucose oxidation by 50%. Ischemia was induced by a 20% flow reduction and β-adrenergic stimulation, which resulted in myocardial lactate production. During ischemia MCD inhibition elevated malonyl-CoA content fourfold, reduced free fatty acid oxidation rate by 87%, and resulted in a 50% decrease in lactate production. Moreover, fatty acid oxidation during ischemia was inversely related to the tissue malonyl-CoA content ( r = −0.63). There were no differences between groups in myocardial ATP content, the activity of pyruvate dehydrogenase, or myocardial contractile function during ischemia. Thus modulation of MCD activity is an effective means of regulating myocardial fatty acid oxidation under normal and ischemic conditions and reducing lactate production during demand-induced ischemia.

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44

Gagnaire, J., X. Y. Wang, L. Chapon, P. Moulin, and B. Marrot. "Kinetic study of compost liquor nitrification." Water Science and Technology 63, no. 5 (March 1, 2011): 868–76. http://dx.doi.org/10.2166/wst.2011.263.

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This study is a first kinetic approach about the compost liquor treatment by activated sludge. This industrial wastewater is highly loaded in organic and nitrogen compounds (COD≈12,000 mg L−1 and NH4+-N≈4,000 mg L−1). The possibility of its treatment in an urban WWTP is studied measuring ammonia oxidation rate with non-acclimated sludge to the industrial effluent. Compost liquor appears as an inhibitor substrate. The ammonia oxidation rate can be modelled by the Haldane model: UMAX=0.180 d−1, KS=12.0 mgN.L−1 and KI=26.0 mgN.L−1. The ammonia oxidation rate also follows for a synthetic substrate which has the same pollutant load as the real substrate. In this case, the ammonia oxidation rate can be modelled by the Monod model: UMAX=0.073 d−1 and KS=4.3 mgN.L−1. This result confirms that the ammonia oxidising bacteria are inhibited by the real wastewater. The following-up of nitrate production shows also the inhibition of nitrite oxidising bacteria. The compost liquor treatment seems not possible in an urban WWTP (<50,000 p.e.). That’s why a specific WWTP is recommended and an acclimation step of activated sludge is essential.

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45

Zhu, Yuanzhi, Xifan Chen, Yaqi Cao, Wenchao Peng, Yang Li, GuoLiang Zhang, Fengbao Zhang, and Xiaobin Fan. "Reversible intercalation and exfoliation of layered covalent triazine frameworks for enhanced lithium ion storage." Chemical Communications 55, no. 10 (2019): 1434–37. http://dx.doi.org/10.1039/c8cc10262g.

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Layered covalent triazine frameworks can be exfoliated into 1–2 layered nanosheets via acid–base intercalation and subsequent oxidation exfoliation to obtain much improved specific capacitance and rate performance for Li ion battery anode.

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Awata, Takanori, Mamoru Oshiki, Tomonori Kindaichi, Noriatsu Ozaki, Akiyoshi Ohashi, and Satoshi Okabe. "Physiological Characterization of an Anaerobic Ammonium-Oxidizing Bacterium Belonging to the “Candidatus Scalindua” Group." Applied and Environmental Microbiology 79, no. 13 (April 12, 2013): 4145–48. http://dx.doi.org/10.1128/aem.00056-13.

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ABSTRACTThe phylogenetic affiliation and physiological characteristics (e.g.,Ksand maximum specific growth rate [μmax]) of an anaerobic ammonium oxidation (anammox) bacterium, “CandidatusScalindua sp.,” enriched from the marine sediment of Hiroshima Bay, Japan, were investigated. “CandidatusScalindua sp.” exhibits higher affinity for nitrite and a lower growth rate and yield than the known anammox species.

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Wardhani, Sri, Danar Purwonugroho, and Diah Mardiana. "PHENOL OXIDATION USING NATURAL ZEOLITE SUPPORTED METAL ION CATALYST." Indonesian Journal of Chemistry 8, no. 2 (June 17, 2010): 215–18. http://dx.doi.org/10.22146/ijc.21636.

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Phenol which contained in waste water has to be reduced and it could be done by oxygen oxidation. In order to increase the rate of reaction it was needed a catalyst. In this research the capability of various catalysts, namely zeolite-Zn(II), zeolite-Cu(II) and zeolite-Co(II)in oxidation of phenol has been investigated. The aim of this research was to study the type of metal ion catalyst towards the percentage of oxidated phenol. The oxidation process were carried out in an aqueous phenol of 100 ppm with oxygen flow rate of 200 mL/min. in the presence of catalysts with 0.2M of initial impregnation concentration. The capabilities of catalysts were performed by calculating the activation energy and it was done at two different temperatures, i.e. 70 and 90 oC. The percentage of oxidated phenol was determinated by measuring its concentration using UV-VIS spectrophotometer. In addition, the impregnated metal was calculated by measuring the ion concentration remains in the filtrate solution and it was determined using Atomic Absorption Spectrophotometer. The results showed that metal ion types affected the catalytic activity. The order of phenol oxidationactivity decreased as Co(II) > Cu(II) > Zn(II). The surface characteristics of catalysts were supported by pore volume and pore diameter i.e 0.009 cm3/g and 16.59 Å for Zn(II) whereas specific surface area was 10.32 m2/g for Zn(II), 0.004 cm3/g and 24.37 Å for Cu(II) whereas specific surface area was 3.57 m2/g for Cu(II), 0.001 cm3/g and 19.63 Å for Co(II) whereas specific surface area was 10.26m2/g for Co(II). Keywords: phenol,natural zeolite, catalyst, oxidation

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Kampschreur, M. J., N. C. G. Tan, C. Picioreanu, M. S. M. Jetten, I. Schmidt, and M. C. M. van Loosdrecht. "Role of nitrogen oxides in the metabolism of ammonia-oxidizing bacteria." Biochemical Society Transactions 34, no. 1 (January 20, 2006): 179–81. http://dx.doi.org/10.1042/bst0340179.

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Ammonia-oxidizing bacteria (AOB) can use oxygen and nitrite as electron acceptors. Nitrite reduction by Nitrosomonas is observed under three conditions: (i) hydrogen-dependent denitrification, (ii) anoxic ammonia oxidation with nitrogen dioxide (NO2) and (iii) NOx-induced aerobic ammonia oxidation. NOx molecules play an important role in the conversion of ammonia and nitrite by AOB. Absence of nitric oxide (NO), which is generally detectable during ammonia oxidation, severely impairs ammonia oxidation by AOB. The lag phase of recovery of aerobic ammonia oxidation was significantly reduced by NO2 addition. Acetylene inhibition tests showed that NO2-dependent and oxygen-dependent ammonia oxidation can be distinguished. Addition of NOx increased specific activity of ammonia oxidation, growth rate and denitrification capacity. Together, these findings resulted in a hypothetical model on the role of NOx in ammonia oxidation: the NOx cycle.

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Xiao, Xu, Huiyuan Hou, Victor Lin, Daisy Ho, Kyle Tran, Briana Che, Adam May, et al. "Probucol Protects Rats from Cardiac Dysfunction Induced by Oxidative Stress following Cardiopulmonary Resuscitation." Oxidative Medicine and Cellular Longevity 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/1284804.

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Objective. To investigate the protective effect of probucol on induced cardiac arrest (CA) rats and possible mechanisms.Methods. Sprague Dawley rats were orally administrated with probucol at different dosage or vehicle for 5 days and subjected to a CA model by electrical stimulation, followed by cardiopulmonary resuscitation (CPR). The return of spontaneous circulation (ROSC) rate, antioxidant enzyme activities, and lipid oxidation markers were measured in serum and myocardium. Hemodynamic parameters and myocardial functions of animals were analyzed. Expression of erythroid-derived 2-like 2 (NFE2L2) and Kelch-like ECH-associated protein 1 (KEAP1) in the myocardium were examined with immunohistochemistry.Results. Probucol treatment significantly increased the ROSC rate and survival time of CA-induced rats. After ROSC, levels of oxidation-specific markers were decreased, while activities of antioxidant enzymes were increased significantly in probucol treatment groups. The probucol treatment improves hemodynamic parameters and myocardial functions. These parameter changes were in a dose-dependent manner. In the probucol treatment groups, the expression of KEAP1 was downregulated, while that of NFE2L2 was upregulated significantly.Conclusion. In the CA-induced rat model, probucol dose dependently improved the ROSC rate, prolonged survival time, alleviated oxidative stress, and improved cardiac function. Such protective effects are possibly through regulations of the KEAP1-NFE2L2 system.

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Ali, Md Eaqub, Md Motiar Rahman, Shaheen M. Sarkar, and Sharifah Bee Abd Hamid. "Heterogeneous Metal Catalysts for Oxidation Reactions." Journal of Nanomaterials 2014 (2014): 1–23. http://dx.doi.org/10.1155/2014/192038.

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Oxidation reactions may be considered as the heart of chemical synthesis. However, the indiscriminate uses of harsh and corrosive chemicals in this endeavor are threating to the ecosystems, public health, and terrestrial, aquatic, and aerial flora and fauna. Heterogeneous catalysts with various supports are brought to the spotlight because of their excellent capabilities to accelerate the rate of chemical reactions with low cost. They also minimize the use of chemicals in industries and thus are friendly and green to the environment. However, heterogeneous oxidation catalysis are not comprehensively presented in literature. In this short review, we clearly depicted the current state of catalytic oxidation reactions in chemical industries with specific emphasis on heterogeneous catalysts. We outlined here both the synthesis and applications of important oxidation catalysts. We believe it would serve as a reference guide for the selection of oxidation catalysts for both industries and academics.

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Journal articles on the topic 'Specific oxidation rate'

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