Increase In Oxidation Rate Research Articles

Impaired Metabolic Flexibility to High-Fat Overfeeding Predicts Future Weight Gain

The ability to switch fuels for oxidation in response to changes in macronutrient composition of diet (metabolic flexibility) may be informative of the individual susceptibility to weight gain. Seventy-nine healthy, weight-stable subjects underwent 24-h assessments of energy expenditure and respiratory quotient (RQ) in a whole-room calorimeter during energy balance (EBL; 50% carbohydrate, 30% fat) and then during 24-h fasting and three 200% overfeeding diets in a crossover design. Metabolic flexibility was defined as the change in 24-h RQ from EBL during fasting and standard (SOF: 50% carbohydrate, 30% fat), high-fat (FNP: 60% fat, 20% carbohydrate), and high-carbohydrate (CNP: 75% carbohydrate, 5% fat) overfeeding diets. Free-living weight change was assessed after 6 and 12 months. Compared to EBL, RQ decreased on average by 9% during fasting and by 4% during FNP, while increasing by 4% during SOF and by 8% during CNP. Smaller decrease in RQ, reflecting smaller increase in lipid oxidation rate, during FNP but not during other diets, predicted greater weight gain at both 6 and 12 months. An impaired metabolic flexibility to acute, high-fat overfeeding identify individuals prone to gain weight, indicating that the individual capacity to oxidize dietary fat is a metabolic predictor of weight change.

Characteristics of fine particle explosive growth events in Beijing, China: Seasonal variation, chemical evolution pattern and formation mechanism

Fine particle explosive growth (FPEG) events are frequently observed in heavy haze episodes in Beijing, the characteristics and formation mechanism of which remain not fully understood. In this study, a five year (2013–2017) online observation was conducted in Beijing and the chemical evolution pattern of FPEG events was analyzed to understand its formation mechanism. A total of 132 FPEG events were identified, and steadily decreased from 39 events in 2013 to 19 events in 2017. More than 70% of the FPEG events occurred in winter and autumn, which coincides with adverse weather conditions and enhanced primary emissions. Organic matter (OM) was the dominated components (~30%) in PM2.5, but it only accounted for 10% of total FPEG events as a driven factor, because its contribution usually decreased when the FPEG events developed. In contrast, the secondary inorganic species were the dominated driven factors, and sulfate-driven events accounted >50%. During the period of 2013–2017, the contribution from regional sources decreased significantly mainly due to the reduction of emissions from regional sources, while the contribution from local sources remained largely unchanged, indicating that the local secondary transformation played a leading role in promoting the FPEG events. The low nitrogen oxidation rates (NOR, 0.12 ± 0.07) and the weak increase trend of NOR with elevated RH were observed, indicating the formation of which might be promoted by the homogenous reaction between HNO3 and NH3. In contrast, a significant increase in sulfur oxidation rate (SOR, 0.50 ± 0.19) was observed when RH > 50%, suggesting enhanced heterogeneous oxidation of SO2 in FPEG events. In addition, our analysis suggest the S (IV) heterogeneous oxidation rates in FPEG events depend mainly on the aerosol liquid water content (ALWC) in addition to the aerosol acidity. This study provides observational evidence for understanding the formation mechanism of FPEG events in Beijing.

288-LB: Effects of the Hepatic Mitochondrial Calcium Uniporter on Hepatic Gluconeogenesis and Mitochondrial Metabolism in Awake Mice

Increased hepatic glucose production, due to increased rates of gluconeogenesis, is a contributor to both fasting and postprandial hyperglycemia in patients with T2D. Recent evidence implicates a role for hepatic calcium signaling in mediating glucagon's effect to stimulate glucose production and mitochondrial oxidation; however, the cellular and molecular mechanisms by which glucagon promotes these alterations remain poorly understood. We hypothesize that an acute physiological increase in plasma glucagon concentrations will increase cytosolic and mitochondrial calcium concentrations, promoting increases in rates of hepatic mitochondrial oxidation and gluconeogenesis in a transcription-independent manner. To test this hypothesis, we used mice with a liver-specific loss of the mitochondrial calcium uniporter (MCU), which is the main transporter that allows rapid transport of calcium into the mitochondrial matrix. We found that glucagon increased oxygen consumption rate by 80% (p<0.0001) in WT hepatocytes, while this effect was abrogated in MCU KO hepatocytes. We also measured hepatic mitochondrial oxidation (VCS) in vivo using Positional Isotopomer NMR Tracer Analysis (PINTA) and found a 74% decrease in VCS (p=0.05) in MCU KO mice compared to WT mice. This suggests that tightly regulated mitochondrial calcium signaling is necessary for regulating hepatic mitochondrial oxidation. Next, we measured intrahepatic lipolysis and hepatic gluconeogenesis in vitro and in vivo. We found that glucagon increased lipolysis (p=0.05) and glucose production (p=0.024) by ∼1.5 fold in MCU KO compared to WT hepatocytes. Furthermore, in vivo PINTA results showed that glucagon increased pyruvate carboxylase flux (VPC) by 68% (p=0.08) in MCU KO mice. Taken together, these results suggest that mitochondrial calcium signaling through MCU is necessary to regulate the effect of glucagon to modulate hepatic gluconeogenesis and mitochondrial oxidation. Disclosure J. Lee: None. L. Goedeke: None. Y. Zhang: None. R.J. Perry: Research Support; Self; AstraZeneca. R. Goodman: None. V. Mootha: Advisory Panel; Self; Janssen Pharmaceuticals, Inc. Consultant; Self; 5AM Ventures. Other Relationship; Self; Raze Therapeutics. G.I. Shulman: Advisory Panel; Self; AstraZeneca, Janssen Research & Development, Merck & Co., Inc. Advisory Panel; Spouse/Partner; Merck & Co., Inc. Board Member; Self; Novo Nordisk A/S. Consultant; Self; Aegerion Pharmaceuticals, IMetabolic BioPharma Corporation, Longitude Capital, Nimbus Discovery, Inc., Staten Biotechnology B.V. Funding National Institutes of Health

Synthesis of Ni–Co-Fe layered double hydroxide and Fe2O3/Graphene nanocomposites as actively materials for high electrochemical performance supercapacitors

Supercapacitors, as a fresh class of electrochemical energy storage devices are currently of widespread interest in energy storage, which has become a research area due to outstanding performance features such as high lifetime, high power density, high safety, and low maintenance costs. In this study, we synthesize Co, Ni and Fe layered double hydroxides (NiCoFe–LDHs) on Nickel–foam as novel positive electrode and Fe2O3/Graphene as novel negative electrode for supercapacitve energy storage application. The electrochemical efficiencies of NiCoFe–LDHs have been explored and optimized by changing the amounts of Ni, Co and Fe via electrochemical method. The NiCoFe–LDH sample with Ni:Co:Fe ratio of 2:1:1 has the maximum specific capacity, that is related to the synergistic effect of the presence of Co, Ni and Fe which causes increased conductivity, increased oxidation rate of insulators such as Ni(OH)2, increases the formation rate of CoIV active sites and facilitates the penetration of OH−and therefore accelerates the kinetic of process. NiCoFe-LDHs nanocomposite shows a significant and high specific capacitance of 3130 Fg-1 at a density of current of 1 Ag-1. Furthermore, an asymmetric supercapacitor are created using NiCoFe-LDHs as the positive and the Fe2O3/Graphene as the negative electrode exhibits the maximum energy density of 101 Whkg−1and the power density of 91.5 KWkg−1, as well as a long-term cycling stability (82.5% capacity retention after 5000 cycles).

Analytical model for methane migration through fractured unsaturated landfill cover soil

Migration of gas in the fractured porous media plays an important role in geoenvironmental engineering issues. Compacted clay liners (CCLs) are extensively used as engineering barriers for groundwater and soil pollution induced by landfill contaminant transport. Analytical model and semi-analytical model were developed for methane transport in fractured CCL by using Laplace transformation and Laplace inversion using Stehfest method. Methane diffusion and oxidation in the matrix of CCL and gas advection-diffusion in the fracture were considered. Dimensionless analysis shows that advection plays a more important role than diffusion for methane transport through the fracture. Diffusion and oxidation of methane in the matrix of CCL have relatively less influences on methane transport in the fracture. The steady-state methane surface flux for the case with Dm = 3.14 × 10−9 m2/s is 1.02 and 1.5 times greater than that with Dm = 3.14 × 10−8 m2/s when the fracture width 2b = 5 mm and 2b = 3 mm, respectively. Methane oxidation rate in the matrix of CCL (λ1) plays a more important role on methane transport in fracture than methane oxidation rate in the fracture (λ2). When λ1 and λ2 increase by one order of magnitude, the steady-state surface fluxes decrease by factors of 1.05 and 1.53, respectively. Transport of methane can be greatly restrained by the compost-amended CCL due to the increase of methane oxidation rate. The proposed semi-analytical and analytical model can be used in the design and assessment of cover system for landfill and mining facilities with different soil moisture contents.

Investigation of Hydrazine Electro-Oxidation on Zinc-Cobalt Coating Modified with Gold Nanoparticles

In this study, the electro-oxidation of hydrazine in an alkaline medium was investigated on the zinc-cobalt (ZnCo) coating, which was deposited on the titanium (Ti) surface and then modified with low amounts of gold nanoparticles (AuNPs). The AuNPs-ZnCo/Ti catalysts with different amount of AuNPs were prepared via a facile electrochemical deposition technique followed by a simple and low-cost galvanic displacement. Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Analysis and Inductively Coupled Plasma Optical Emission Spectroscopy were used for the characterization of the surface morphology, structure and composition of the as-prepared AuNPs-ZnCo/Ti catalysts. Electrocatalytic behavior of catalysts was investigated towards the electro-oxidation of hydrazine in an alkaline medium using Cyclic Voltammetry. It was found that the AuNPs-ZnCo/Ti catalysts were prepared with the Au loadings of 31, 63 and 306 µg cm-2 after the immersion of the ZnCo/Ti catalyts into the 1 mM HAuCl4 solution for 0.5, 1 and 5 min, respectively. Moreover, the ZnCo/Ti catalysts modified by AuNPs has significantly higher catalytic activity towards the electro-oxidation of hydrazine as compared to that of the ZnCo/Ti catalyst. Additionaly, modification of the ZnCo/Ti catalyst by AuNPs leads to the rather pronounced shift in hydrazine oxidation potential to more negative potential region and is followed by a substantial increase in direct hydrazine oxidation rate as compared to that of the unmodified ZnCo/Ti catalyst.

Voltammetric determination of ascorbic acid with zinc oxide modified glassy carbon electrode

Zinc oxide (ZnO) nanostructures electrodeposited from aqueous zinc nitrate solution at 70 °C onto glassy carbon electrode (GCE) were used as electrochemical detectors. The morphology, structure, chemical composition and conductivity of the as-deposited layers were determined using scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray analysis and UV–Vis spectroscopy. A highly oriented crystalline ZnO deposit made of a dense array of randomly oriented hexagonal nanorods was obtained without any additives in solution. The electrocatalytic oxidation of ascorbic acid (AA) was studied using cyclic voltammetry in 0.1 M phosphate buffer solution at pH 6.8. Comparing the response for AA oxidation on the bare and modified electrodes, the peak potential was shifted to − 0.45 V on ZnO/GCE with higher current densities and transfer coefficient, due to a simultaneous increase in oxidation rate and surface area. A linear relationship was determined between the anodic peak current and the AA concentration in the range of 0.1–5 mM.

Blunted fat oxidation upon submaximal exercise is partially compensated by enhanced glucose metabolism in children, adolescents, and young adults with Barth syndrome.

Barth syndrome (BTHS) is a rare X-linked condition resulting in abnormal mitochondria, cardioskeletal myopathy, and growth delay; however, the effects of BTHS on substrate metabolism regulation and their relationships with tissue function in humans are unknown. We sought to characterize glucose and fat metabolism during rest, submaximal exercise, and postexercise rest in children, adolescents, and young adults with BTHS and unaffected controls and examine their relationships with cardioskeletal energetics and function. Children/adolescents and young adults with BTHS (n = 29) and children/adolescent and young adult control participants (n = 28, total n = 57) underwent an infusion of 6'6'H2 glucose and U-13 C palmitate and indirect calorimetry during rest, 30-minutes of moderate exercise (50% ), and recovery. Cardiac function, cardioskeletal mitochondrial energetics, and exercise capacity were examined via echocardiography, 31 P magnetic resonance spectroscopy, and peak exercise testing, respectively. The glucose turnover rate was significantly higher in individuals with BTHS during rest (33.2 ± 9.8 vs 27.2 ± 8.1 μmol/kgFFM/min, P < .01) and exercise (34.7 ± 11.2 vs 29.5 ± 8.8 μmol/kgFFM/min, P < .05) and tended to be higher postexercise (33.7 ± 10.2 vs 28.8 ± 8.0 μmol/kgFFM/min, P < .06) compared to controls. Increases in total fat (-3.9 ± 7.5 vs 10.5 ± 8.4 μmol/kgFFM/min, P < .0001) and plasma fatty acid oxidation rates (0.0 ± 1.8 vs 5.1 ± 3.9 μmol/kgFFM/min, P < .0001) from rest to exercise were severely blunted in BTHS compared to controls. Conclusion: An inability to upregulate fat metabolism during moderate intensity exercise appears to be partially compensated by elevations in glucose metabolism. Derangements in fat and glucose metabolism are characteristic of the pathophysiology of BTHS. A severely blunted ability to upregulate fat metabolism during a modest level of physical activity is a defining pathophysiologic characteristic in children, adolescents, and young adults with BTHS.

Thioesterase Superfamily Member 2 Promotes Hepatic VLDL Secretion by Channeling Fatty Acids Into Triglyceride Biosynthesis.

In nonalcoholic fatty liver disease (NAFLD), triglycerides accumulate within the liver because the rates of fatty acid accrual by uptake from plasma and de novo synthesis exceed elimination by mitochondrial oxidation and secretion as very low-density lipoprotein (VLDL) triglycerides. Thioesterase superfamily member 2 (Them2) is an acyl-coenzyme A (CoA) thioesterase that catalyzes the hydrolysis of fatty acyl-CoAs into free fatty acids plus CoASH. Them2 is highly expressed in the liver, as well as other oxidative tissues. Mice globally lacking Them2 are resistant to diet-induced obesity and hepatic steatosis, and exhibit improved glucose homeostasis. These phenotypes are attributable, at least in part, to roles of Them2 in the suppression of thermogenesis in brown adipose tissue and insulin signaling in skeletal muscle. To elucidate the hepatic function of Them2, we created mice with liver-specific deletion of Them2 (L-Them2-/- ). Although L-Them2-/- mice were not protected against excess weight gain, hepatic steatosis or glucose intolerance, they exhibited marked decreases in plasma triglyceride and apolipoprotein B100 concentrations. These were attributable to reduced rates of VLDL secretion owing to decreased incorporation of plasma-derived fatty acids into triglycerides. The absence of hepatic steatosis in L-Them2-/- mice fed chow was explained by compensatory increases in rates of fatty acid oxidation and by decreased de novo lipogenesis in high fat-fed mice. Consistent with a role for Them2 in hepatic VLDL secretion, THEM2 levels were increased in livers of obese patients with NAFLD characterized by simple steatosis. Conclusion: Them2 functions in the liver to direct fatty acids toward triglyceride synthesis for incorporation into VLDL particles. When taken together with its functions in brown adipose and muscle, these findings suggest that Them2 is a target for the management of NAFLD and dyslipidemia.

Anodic Oxidation of Hydrogen-Transferred Silicon-on-Insulator Layers

The anodic oxidation rate of silicon-on-insulator films fabricated by hydrogen transfer is studied as a function of the temperature of subsequent annealing. It is established that the oxidation rate of transferred silicon-on-insulator films is five times lower compared to the oxidation rate of bulk single-crystal silicon samples. The oxidation rate increases, as the annealing temperature is elevated in the range 700–1100°C and as the depth of gradually removed anode-oxidized layers is increased. The results obtained in the study are attributed to an increase in the efficiencies of the anodic current and oxygen–silicon interatomic interaction due to the annealing of defects and due to release of hydrogen from the bound state, respectively. The formation of hydrogen bubbles in the surface region of silicon due to the diffusion of hydrogen, released in the process of the oxidation reaction, towards micropores in the silicon-on-insulator layer is detected.

Cardiac-specific deficiency of the mitochondrial calcium uniporter augments fatty acid oxidation and functional reserve

The mitochondrial calcium uniporter (MCU) relays cytosolic Ca2+ transients to the mitochondria. We examined whether energy metabolism was compromised in hearts from mice with a cardiac-specific deficiency of MCU subjected to an isoproterenol (ISO) challenge. Surprisingly, isolated working hearts from cardiac MCU-deficient mice showed higher cardiac work, both in the presence or absence of ISO. These hearts were not energy-starved, with ISO inducing a similar increase in glucose oxidation rates compared to control hearts, but a greater increase in fatty acid oxidation rates. This correlated with lower levels of the fatty acid oxidation inhibitor malonyl CoA, and to an increased stimulatory acetylation of its degrading enzyme malonyl CoA decarboxylase and of the fatty acid β-oxidation enzyme β-hydroxyacyl CoA dehydrogenase. We conclude that impaired mitochondrial Ca2+ uptake does not compromise cardiac energetics due to a compensatory stimulation of fatty acid oxidation that provides a higher energy reserve during acute adrenergic stress.

Acclimation of methane emissions from rice paddy fields to straw addition.

Straw incorporation is a common long-term practice to improve soil fertility in croplands worldwide. However, straw amendments often increase methane (CH4) emissions from rice paddies, one of the main sources of anthropogenic CH4. Intergovernmental Panel on Climate Change (IPCC) methodologies to estimate CH4 emissions from rice agriculture assume that the effect of straw addition remains constant over time. Here, we show through a series of experiments and meta-analysis that these CH4 emissions acclimate. Effects of long-term (>5 years) straw application on CH4 emissions were, on average, 48% lower than IPCC estimates. Long-term straw incorporation increased soil methanotrophic abundance and rice root size, suggesting an increase in CH4 oxidation rates through improved O2 transport into the rhizosphere. Our results suggest that recent model projections may have overestimated CH4 emissions from rice agriculture and that CH4 emission estimates can be improved by considering the duration of straw incorporation and other management practices.

Commercial steel wool used for Zero Valent Iron and as a source of dissolved iron in a combined red-ox process for pentachlorophenol degradation in tap water

Pentachlorophenol solutions in tap water were treated with a combined process of zero valent iron (ZVI) reduction followed by a photo-Fenton oxidation. Commercial steel wool was used as ZVI source, demonstrating its effectivity for pentachlorophenol de-chlorination at acidic pH values. The reductive pathway was monitored by the use of excitation emission matrices, showing the transformation of the initial compound into the fluorescent species 4-chlorophenol and phenol.While the use of tap water represented a drawback in photo-Fenton oxidative reactions (at least half kinetic constants values) an improvement was achieved when the reductive stage was applied in the studied pH range. The transformation of pentachlorophenol into phenol produced an increase in oxidative stage rate of about 8 times. This fact could be related to the treatment time and hydrogen peroxide consumption of the photo-Fenton process, enhancing the economic viability. Furthermore, the de-chlorination of the pentachlorophenol minimized the possibility of releasing toxic by-products in the photo-Fenton process.

Анодное окисление слоев кремний-на-изоляторе, созданных методом водородного переноса

AbstractThe anodic oxidation rate of silicon-on-insulator films fabricated by hydrogen transfer is studied as a function of the temperature of subsequent annealing. It is established that the oxidation rate of transferred silicon-on-insulator films is five times lower compared to the oxidation rate of bulk single-crystal silicon samples. The oxidation rate increases, as the annealing temperature is elevated in the range 700–1100°C and as the depth of gradually removed anode-oxidized layers is increased. The results obtained in the study are attributed to an increase in the efficiencies of the anodic current and oxygen–silicon interatomic interaction due to the annealing of defects and due to release of hydrogen from the bound state, respectively. The formation of hydrogen bubbles in the surface region of silicon due to the diffusion of hydrogen, released in the process of the oxidation reaction, towards micropores in the silicon-on-insulator layer is detected.

Effect of biotin supplementation on fatty acid metabolic pathways in 3T3-L1 adipocytes.

Several studies have shown that pharmacological concentrations of biotin decrease serum lipid concentrations and the expression of lipogenic genes. Previous studies on epididymal adipose tissue in mice revealed that 8 weeks of dietary biotin supplementation increased the protein abundance of the active form of AMPK and the inactive forms acetyl CoA carboxylase (ACC)-1 and - 2, and decreased serum free fatty acid concentrations but did not affect lipolysis. These data suggest that pharmacological concentrations of the vitamin might affect fatty acid metabolism. In this work, we investigated the effects of pharmacological biotin concentrations on fatty acid synthesis, oxidation, and uptake in 3T3-L1 adipocytes. Similar to observations in mice, biotin-supplemented 3T3-L1 adipose cells increased the protein abundance of active T172 -AMPK and inactive ACC-1 and -2 forms. No changes were observed in the expression of the transcriptional factor PPARα and carnitine-palmitoyltransferase-1 (CPT-1). Radiolabeled assays indicated a decrease in fatty acid synthesis; an increase in fatty acid oxidation and fatty acid incorporation rate into the lipid fraction between control cells and biotin-supplemented cells. The data revealed an increase in the mRNA abundance of the fatty acid transport proteins Fatp1 and Acsl1 but not Cd36 or Fatp4 mRNA. Furthermore, the abundance of glycerol phosphate acyl transferase-3 protein was increased. Triglyceride content was not affected. Lipid droplet numbers showed an increase and their areas were smaller in the biotin-supplemented group. In conclusion, these data indicate that biotin supplementation causes a decrease in fatty acid synthesis and an increase in its oxidation and uptake. © 2018 BioFactors, 45(2):259-270, 2019.

Influence of cadmium on oxidative stress and NADH oscillations in mussel mitochondria

Biological organisms evolved to take advantage of recurring environmental factors which enabled them to assimilate and process metabolic energy for survival. Mitochondria display non-linear oscillations in NADH levels (i.e. wave behavior) that result from the balance between NADH production (aerobic glycolysis) and oxidation for ATP synthesis. The purpose of this study was to examine the effects of cadmium (Cd) on mitochondrial NADH oscillations in quagga mussels Dreissena bugensis exposed to 50 and 100 μg/L CdCl2 for 7 days at 15 °C. Metallothionein (MT) levels, thioredoxin reductase (TrxR) activity and NADH oxidation rate were also determined, as were oscillations in NADH and the formation of dissipative structures (turbidity), in isolated mitochondria suspensions. The results show that exposure to Cd readily induced MT levels at both concentrations tested and that TrxR and NADH oxidase activity was induced at 100 μg/L Cd only. In control mussels, NADH levels oscillated in mitochondria suspensions with a natural period of 2 to 2.5 min for up to 40 min. Exposure to Cd increased the complexity of the frequency profile of NADH oscillations and reduced the amplitudes of the natural signal with a period of 2 to 2.5 min. The formation of dissipative structures decreased in response to a Cd concentration of 100 μg/L but increased at a level of 50 μg/L. The amplitudes at the natural frequency were significantly correlated with NADH oxidase activity (r = −0.91) and with the formation of dissipative structures (r = −0.59). We conclude that Cd could alter the natural frequency in oscillations of NADH in mitochondria, thereby contributing to an increase in NADH oxidation rate and disruption of the spatial organization of mitochondria in suspension. In conclusion, changes in the wave behavior of NADH in mitochondria are proposed as a novel biomarker of toxicity in aquatic organisms.

Catalytic Etching of Platinoid Gauzes During the Oxidation of Ammonia by Air. Reconstruction of the Surface of a Platinoid Gauze Backside in the Course of Ammonia Oxidation at 1133 K

Scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to study microstructure, morphology and chemical composition of the surface and near-surface layers of polycrystalline wire of commercial platinoid gauzes containing Pt (81 wt %), Pd (15 wt %), Rh (3.5 wt %), and Ru (0.5 wt %) after ammonia oxidation (10 vol % NH3) by air at 1133 K for 50 h in the presence of these gauzes. Upon the completion of the catalytic reaction of ammonia oxidation, reconstruction (catalytic etching) of the surface layer on the backside of gauze wire (in the direction of the gas flow) was observed, in which the regions with different degrees of etching were identified. The analysis of these regions showed that the catalytic etching of the platinoid wire is initiated by etching the surface layer in the region of grain boundaries and dislocations in the course of highly exothermic catalytic reaction of ammonia oxidation by oxygen penetrated in the regions of defects. The regions with minimal etching contain smooth grains with crystalline terraces, 50 nm high, and with etching pits with size of ~72 nm in a concentration of 4.2 × 108 cm–2. The region with medium etching includes rough grains with etching pits with size of ~85 nm in a concentration of 2.5 × 108 cm–2. The regions with maximal etching consist of recrystallized grains with large pores with sizes of 350–400 nm in concentration of 8.9 × 106 cm–2. These grains are separated by voids with a width of 1–5 μm and a depth of 10 μm, which increases the specific surface area in the surface layer of wire. The growth of the specific surface area of the platinoid wire is accompanied by an increase in the volume rate of ammonia oxidation and, as a result, local overheating due to the high exothermicity of the reaction. With increasing temperature, the rate of diffusion of metal atoms increases, which, in turn, accelerates etching in this region. These processes lead to increasing the region of etching along the wire, which points to the autocatalytic regime of etching of platinoid gauzes in ammonia oxidation by oxygen.

PO-294 Effects of HIIT on FTO protein expression and its relationship with glucose and fat metabolism

Objective FTO (Fat mass and obesity-associated) is associated with increased risk of obesity and type 2 diabetes incurrence. Studies have shown that the expression of FTO protein in skeletal muscle and adipose tissue is related to the oxidation rate of whole body substrate. With the increase of age, the body's carbohydrate oxidation rate decreases, the fat oxidation rate increases, and at the meanwhile the expression of FTO protein in skeletal muscle decreases and that in adipose increases. HIIT is very helpful for inhibiting obesity, insulin resistance and type 2 diabetes. So the purpose of this study is to investigate the effect of HIIT exercise on the expression of FTO protein in rats and its relationship to glucose and fat metabolism.&#x0D; Methods 20 Male, 3-week-old SD rats were randomly divided into two groups, each group has 10 rats. C group: sedentary; HIIT group: high-intensity intermittent training group (85% ~ 90% VO2max exercise for 6min, 50% VO2max exercise interval 4min, repeated 6 times. 5 times/week ,4 weeks). All subjects were maintained in a free facility with constant temperature of 25°C, light-dark cycle of 12/12 h and free access to water. 48 hours after the last exercise, all samples were taken with an overnight fast. The expression of FTO protein in skeletal muscle and adipose tissue was measured by Western Blot. Serum insulin was tested by ELISA; Estimation of blood glucose was tested by Glucose oxidase method.&#x0D; Results 1.The expression of FTO protein in skeletal muscle was significantly higher than that of group C (P &lt;0.01); The expression of FTO protein in adipose tissue of HIIT group was significantly lower than that of group C (P &lt;0.05); 2. Serum insulin levels of group HIIT was significantly lower than that of group C (p &lt;0.01); And the blood glucose of group HIIT was significantly lower than that of group C (p &lt;0.01). 3. Serum LDL-C of group HIIT was significantly lower than that of group C (p &lt;0.01), and serum HDL-C of group HIIT was significantly higher than that of group C (p &lt;0.01);4. Correlation analysis showed that serum insulin level was negatively correlated with skeletal muscle FTO protein expression (R = -0.454, p &lt; 0.05). Correlation analysis showed that serum LDL-C levels was positively correlated with adipose tissue FTO protein expression (R=0.559, p &lt; 0.05) and serum HDL-C levels was negatively correlated with adipose tissue FTO protein expression (R=-0.474, p &lt; 0.05).&#x0D; Conclusions 1. HIIT can increase the protein expression of FTO in rat skeletal muscle and decrease the expression of FTO protein in adipose tissue; 2. HIIT can regulate glucose metabolism and lipid metabolism in rats; 3. The regulation of glucose metabolism by HIIT may be related to the increase of FTO protein expression in skeletal muscle. The regulation of lipid metabolism may be related to the reduction of FTO protein expression in adipose tissue.

Site-directed mutagenesis of cysteine residues alters oxidative stability of fetal hemoglobin

Redox active cysteine residues including βCys93 are part of hemoglobin's “oxidation hotspot”. Irreversible oxidation of βCys93 ultimately leads to the collapse of the hemoglobin structure and release of heme. Human fetal hemoglobin (HbF), similarly to the adult hemoglobin (HbA), carries redox active γCys93 in the vicinity of the heme pocket. Site-directed mutagenesis has been used in this study to examine the impact of removal and/or addition of cysteine residues in HbF. The redox activities of the recombinant mutants were examined by determining the spontaneous autoxidation rate, the hydrogen peroxide induced ferric to ferryl oxidation rate, and irreversible oxidation of cysteine by quantitative mass spectrometry. We found that substitution of γCys93Ala resulted in oxidative instability characterized by increased oxidation rates. Moreover, the addition of a cysteine residue at α19 on the exposed surface of the α-chain altered the regular electron transfer pathway within the protein by forming an alternative oxidative site. This may also create an accessible site for di-sulfide bonding between Hb subunits. Engineering of cysteine residues at suitable locations may be useful as a tool for managing oxidation in a protein, and for Hb, a way to stave off oxidation reactions resulting in a protein structural collapse.

Comprehensive analysis of particle growth rates from nucleation mode to cloud condensation nuclei in boreal forest

Abstract. Growth of aerosol particles to sizes at which they can act as cloud condensation nuclei (CCN) is a crucial factor in estimating the current and future impacts of aerosol–cloud–climate interactions. Growth rates (GRs) are typically determined for particles with diameters (dP) smaller than 40 nm immediately after a regional new particle formation (NPF) event. These growth rates are often taken as representatives for the particle growth to CCN sizes (dP &gt; 50–100 nm). In modelling frameworks, the concentration of the condensable vapours causing the growth is typically calculated with steady state assumptions, where the condensation sink (CS) is the only loss term for the vapours. Additionally, the growth to CCN sizes is represented with the condensation of extremely low-volatility vapours and gas–particle partitioning of semi-volatile vapours. Here, we use a novel automatic method to determine growth rates from below 10 nm to hundreds of nanometres from a 20-year-long particle size distribution (PSD) data set in boreal forest. With this method, we are able to detect growth rates also at times other than immediately after a NPF event. We show that the GR increases with an increasing oxidation rate of monoterpenes, which is closely coupled with the ambient temperature. Based on our analysis, the oxidation reactions of monoterpenes with ozone, hydroxyl radical and nitrate radical all are capable of producing vapours that contribute to the particle growth in the studied size ranges. We find that GR increases with particle diameter, resulting in up to 3-fold increases in GRs for particles with dP ∼ 100 nm in comparison to those with dP ∼ 10 nm. We use a single particle model to show that this increase in GR can be explained with aerosol-phase reactions, in which semi-volatile vapours form non-volatile dimers. Finally, our analysis reveals that the GR of particles with dP &lt; 100 nm is not limited by the condensation sink, even though the GR of larger particles is. Our findings suggest that in the boreal continental environment, the formation of CCN from NPF or sub-100 nm emissions is more effective than previously thought and that the formation of CCN is not as strongly self-limiting a process as the previous estimates have suggested.