Lower Oxidation Rate Research Articles

Sputtered Fe1·5CoNi0.5 coating: An improved protective coating for SOFC interconnect applications

In an attempt to optimize the properties of FeCoNi coating for planar solid oxide fuel cell (SOFC) interconnect application, the coating composition is modified by increasing the ratio of Fe/Ni. An Fe 1·5 CoNi 0.5 (Fe:Co:Ni = 1.5:1:0.5, atomic ratio) metallic coating is fabricated on SUS 430 stainless steel by magnetron sputtering, followed by oxidation in air at 800°C. The Fe 1·5 CoNi 0.5 coating is thermally converted to (Fe,Co,Ni) 3 O 4 and (Fe,Co,Mn,Ni) 3 O 4 without (Ni,Co)O particles. After oxidation for 1680 h, no further migration of Cr is detected in the thermally converted coating region. A low oxidation rate of 5.9 × 10 −14 g 2 cm −4 s −1 and area specific resistance of 12.64 mΩ·cm 2 is obtained for Fe 1·5 CoNi 0.5 coated steels. • Fe 1·5 CoNi 0.5 coating is deposited on SUS 430 stainless steel by magnetron sputtering. • The tri-layer oxide scale is thermally formed on the Fe 1·5 CoNi 0.5 coated steel. • The oxidation resistance of the steel substrate is improved. • The out-migration of Cr is effectively inhibited. • A low ASR of 12.64 mΩ·cm 2 is exhibited.

High temperature oxidation behavior and interface diffusion of Cr3C2-NiCrCoMo/nano-CeO2 composite coatings

The high-temperature oxidation resistance of chromium carbide cermet coating was improved by developing a novel Cr3C2-NiCrCoMo/nano-CeO2 (NCE) composite coating based on the collaborative modification of the multielement alloy adhesive phase. The present study aimed to investigate the influence of nano-CeO2 on the high-temperature oxidation resistance, interfacial element diffusion and oxidation mechanism of the coating deposited by the high-velocity oxygen fuel spraying technology (HVOF). The results showed that the novel NCE coating with the addition of 4 wt% nano-CeO2 resulted in lower oxidation rates of 0.10, 0.23 and 0.39 mg/cm2 at 700–900 °C and superior oxidation resistance compared with the original Cr3C2-NiCrCoMo (NCC) coating because of the improvement of the thickness and denseness of the oxide film. The addition of nano-CeO2 promoted the reaction between oxides and the content of spinel phases generated in the NCE coating oxide film. The oxide film of NCE coating with high content of spinel phases strongly inhibited on the ion diffusion, thus reducing the decarburization of the Cr3C2 particles at the coating-oxide film interface. The present study will contribute to improving the service life of chromium carbide cermet coatings in high-temperature oxidation environments and extending the application of coating.

Oxidation and Cr-evaporation behavior of MnCo based spinel and composite coated AISI 430 steel

This work investigates the importance of the chemical composition and porosity of the coating on reducing the oxidation and Cr-evaporation rate of AISI 430 steel in O2-5%H2O at 800 °C for solid oxide fuel cell (SOFC) interconnect applications. Electrophoretic deposition (EPD) is used to deposit eight different coatings. Mn1.25−0.5xCo1.75−0.5xMxO4 (M = Fe, Cu, and Fe-Cu; and X = 0 and ~0.3) powders are synthesized by the glycine nitrate process (GNP) and applied as spinel (without La2O3) or composite (with La2O3) coatings. The coatings initially show porous structure, and the coating density improvement depends on coating composition. The coating porosity for composite co-doped Fe-Cu MnCo spinel (MCFeCuL) is 28% less than MnCo spinel (MC) after 504 h. All coated samples show lower oxidation and Cr-evaporation rates than uncoated samples. The parabolic oxidation rates are lower for composite coated than the spinel ones, possibly due to the formation of LaCrO3 reducing Cr outward diffusion. Composite MnCo-La2O3 (MCL) shows the lowest oxidation rate. In contrast, coating effectiveness in reducing Cr-evaporation depends on coating density. Cu-doped coatings show less coating porosity with better oxidation and Cr-evaporation behavior than Fe-doped coatings. All coated samples form a densified layer at the thermally grown oxide (TGO) scale/coating interface, playing a crucial role in oxidation resistance and migration of Cr from the TGO scale to the coating. The changes in Cr-evaporation fluxes depending on coating porosity and pore size are calculated and compared with Cr-loss rate measurements. Among the coatings, composite Cu-doped MnCo spinel (MCCuL) and MCFeCuL show better performance than the other ones. This study shows that it is possible to decrease coating porosity and improve the performance of MnCo spinel coatings against corrosion and Cr-evaporation without two-step sintering (at T ≤ 900 °C) procedures.

Impacts of engine lubrication oil-derived ash on soot oxidative reactivity on a catalytic gasoline particulate filter

Characterizing soot oxidation kinetics is crucial for understanding how gasoline particulate filters (GPFs) perform both in terms of filtration efficiency and pressure drop. The most common method for measuring soot oxidative reactivity is thermogravimetric analysis (TGA). Because TGA is an offline method, it may inaccurately predict how soot oxidizes on a GPF, especially if a catalytic washcoat is present that may enhance oxidation rates through surface interactions as the soot loads on the filter. In this work, a novel in-situ soot oxidative reactivity measurement method was developed. The method involved loading a catalytic GPF under high temperature conditions conducive to soot oxidation and measuring the filtration efficiency of 100 nm particles. A correlation was made between filtration efficiency and loaded soot mass on the filter to allow calculation of the soot oxidation rate. The method was evaluated in experiments using a 2.0 L gasoline direct injection (GDI) engine with three oils of varying additive packages, including an oil with a high zinc dialkyldithiophosphate (ZDDP) concentration, a non-additive, pure poly-alpha olefin (PAO) oil, and an oil with a high concentration of calcium sulfonate. Calculated specific soot oxidation rates ranged from ∼0.06–0.6 min−1 and showed strong dependence on GPF inlet gas temperature and lubrication oil additive type. The results clearly demonstrated a catalytic effect of calcium-containing ash particles. Reactivity of soot produced by the engine running with the high calcium containing lubrication oil was increased. Similarly, the results indicated that the catalytic washcoat on the filter increased soot oxidation rates on-filter, especially at low soot loading. Conversely, the ZDDP oil additive exhibited a reactivity inhibiting effect, resulting in lower soot oxidation rates. This work represents the first known in-situ soot oxidative reactivity measurements on a GPF and elucidates the effect of lubrication oil additives and catalytic washcoat on oxidation rate.

Genotype influence on shelf life behaviour of minimal processed loquat (Eriobotrya japonica (Thunb.) Lindl.) fruit: the role of sugar, acid organics and phenolic compounds

BackgroundLoquat cultivars cultivated in Southern Italy are very appreciated by consumers for their sensorial characteristics, such as persistent aroma and taste. Apposite maturity indexes for peeling and processing loquat fruit were investigated to increase diffusion of minimally processed loquat. The genotype’s effect on the minimally processed loquat fruit shelf life and quality harvested at commercial maturity (80% yellow color) was investigated on peeled fruit stored at 5 °C for 10 days. The role of sugars, organic acids and phenols composition was observed through in depth qualitative analysis. In addition, several qualitative analyses were carried out to determine the quality of minimal processed fruit.ResultsLoquat fruits harvested at commercial ripening stage performed very good palatability and flesh color persistency. Late ripening fruits genotypes shown a low rate of pulp oxidation and quality decay, while early ripening fruits were not suitable for fresh-cut. Genotype had a great influence on weight loss, β-carotene content, fruit respiration, ascorbic acid and total phenols content during the shelf life.ConclusionsThis work shows how the amount of the composition of sugars and organic acids as an intrinsic characteristic of genotype influences the quality of loquat fruits minimal processed. The higher values of glucose, sorbitol and ascorbic acid accumulated in the cv ‘Nespolone Trabia’ contributed to a reduction in chilling injury and oxidative stress after cutting.Graphical

Correlating oxidation resistance to stress corrosion cracking of 309L and 308L stainless steel claddings in simulated PWR primary water

Stress corrosion cracking (SCC) growth behaviors of 309L and 308L stainless steel claddings in simulated pressurized water reactor primary water at 325 °C and 350 °C were investigated by compact tension specimens and correlated to the oxide film properties in terms of microstructure. SCC growth rates of 308L were much lower than those of 309L. 309L showed typical intergranular SCC characteristics. The high SCC resistance of 308L was related to the low oxidation rate and crack tip retardation due to the presence of highly networked ferrites. The lower Cr content, as well as less and sparsely distributed δ-ferrite phases in 309L than in 308L, led to more severe local oxidation penetration beneath the metal/inner oxide interface and more porous inner oxide, therefore, contributed to its enhanced SCC growth in 309L. The SCC growth rate results by compact tension specimens are consistent with those by slow strain rate tests.

Effect of preparation method on the mechanism for oxidation of C/C-BN composites

C/C-BN composites and C f /BN/PyC composites exhibiting different structures for pyrolytic carbon (PyC) and boron nitride (BN) were studied comparatively to determine their oxidation behavior. This study used five types of samples. Porous C/C composites were modified with silane coupling agents (APS) and then fully impregnated in water-based slurry of hexagonal boron nitride (h-BN); the resulting C/C-BN preforms were densified by depositing PyC by chemical vapor infiltration (CVI), resulting in three types of C/C-BN composites. The other two C f /BN/PyC composites were obtained by depositing a BN interphase and PyC in carbon fiber preforms by CVI; one was treated with heat, and the other was not. This study was focused on determining how the PyC deposition mechanism, morphology and pore structure were affected by the method of BN introduction. In the 600–900 °C temperature range, the C f /BN/PyC composites and C/C composites underwent oxidation via a mixed diffusion/reaction mode. The C/C-BN composites had a different pore structure due to the formation of nodules comprising h-BN particles; both interfacial debonding and cracking were reduced, resulting in higher resistance to gas diffusion, lower oxidation rate and larger activation energy (Ea) in the temperature range 600–800 °C. In addition, the mechanism for oxidation of C/C-BN composites gradually exhibited diffusion control at 800–900 °C because the formation of h-BN oxidation products healed the defects. The oxidation mechanism was more dependent on pore structure than on BN structure or content.

Tissue-specific responses that constrain glucose oxidation and increase lactate production with the severity of hypoxemia in fetal sheep.

Fetal hypoxemia decreases insulin and increases cortisol and norepinephrine concentrations and may restrict growth by decreasing glucose utilization and altering substrate oxidation. Specifically, we hypothesized that hypoxemia would decrease fetal glucose oxidation and increase lactate and pyruvate production. We tested this by measuring whole body glucose oxidation and lactate production, and molecular pathways in liver, muscle, adipose, and pancreas tissues of fetuses exposed to maternal hypoxemia for 9 days (HOX) compared with control fetal sheep (CON) in late gestation. Fetuses with more severe hypoxemia had lower whole body glucose oxidation rates, and HOX fetuses had increased lactate production from glucose. In muscle and adipose tissue, expression of the glucose transporter GLUT4 was decreased. In muscle, pyruvate kinase (PKM) and lactate dehydrogenase B (LDHB) expression was decreased. In adipose tissue, LDHA and lactate transporter (MCT1) expression was increased. In liver, there was decreased gene expression of PKLR and MPC2 and phosphorylation of PDH, and increased LDHA gene and LDH protein abundance. LDH activity, however, was decreased only in HOX skeletal muscle. There were no differences in basal insulin signaling across tissues, nor differences in pancreatic tissue insulin content, β-cell area, or genes regulating β-cell function. Collectively, these results demonstrate coordinated metabolic responses across tissues in the hypoxemic fetus that limit glucose oxidation and increase lactate and pyruvate production. These responses may be mediated by hypoxemia-induced endocrine responses including increased norepinephrine and cortisol, which inhibit pancreatic insulin secretion resulting in lower insulin concentrations and decreased stimulation of glucose utilization.NEW & NOTEWORTHY Hypoxemia lowered fetal glucose oxidation rates, based on severity of hypoxemia, and increased lactate production. This was supported by tissue-specific metabolic responses that may result from increased norepinephrine and cortisol concentrations, which decrease pancreatic insulin secretion and insulin concentrations and decrease glucose utilization. This highlights the vulnerability of metabolic pathways in the fetus and demonstrates that constrained glucose oxidation may represent an early event in response to sustained hypoxemia and fetal growth restriction.

Negative effect of Hf and Zr co-doping on alumina film growth of nickel-aluminium single-crystals during thermal cyclic oxidation

ABSTRACT The microstructure and cyclic oxidation behaviour of Hf and Zr co-doped B2 NiAl single-crystal alloys at 1473 K were investigated. Hf and Zr co-precipitated into one phase during alloy manufacturing. The RE-free single-crystal alloy obtained a double-layered alumina film comprised of outer equiaxed grains and inner columnar grains and exhibited lower oxidation rate than the corresponding poly-crystal alloy, while the co-doped single-crystal alloy displayed higher oxidation rate than the RE-free single-crystal alloy and no synergistic effect was discovered. The effect of Hf and Zr co-doping on the growth behaviour of the alumina film was discussed. It is proposed that the existence of grain boundaries is an important precondition for activating the reactive element effect. The absence of grain boundaries significantly weakened the positive effect of Hf and Zr co-doping and distinctly magnified its negative effect on the cyclic oxidation resistance of the alloy in the meantime. Highlights Cyclic oxidation behaviour of Hf and Zr co-doped NiAl single-crystals is compared. The undoped alloy obtains a double-layered alumina film during oxidation. The co-doped alloy shows higher alumina film growth rate than the undoped alloy. The absence of alloy grain boundaries suppresses the reactive element effect.

Corrosion studies on multicomponent CoCrFeMnNi(C) thin films in acidic environments

The corrosion resistances of near equimolar CoCrFeMnNi magnetron-sputtered thin films with different carbon concentrations were examined in 0.05 M HCl and 0.05 M H2SO4. Polarization curves were recorded with different scan rates with and without reducing the native oxide. The results showed that the carbon concentration and the experimental conditions affected the electrochemical behaviour mainly in the Cr transpassive region. At potentials above 850 mV, the carbon-containing films were more corrosion resistant in 0.05 M HCl than in 0.05 M H2SO4 due to a lower carbon oxidation rate in 0.05 M HCl, facilitating the formation of a Mn-rich oxide layer.

Strengthened Oxygen Oxidation of Ferrous Ions by A Homemade Venturi Jet Microbubble Generator towards Iron Removal in Hydrometallurgy

Iron normally exists in the form of ferrous ion (Fe2+) in primary ore deposits of valuable metals. To remove iron from hydrometallurgical leaching solution or suspension by precipitation, ferrous ion should be oxidized to ferric ion (Fe3+) first. Due to the low oxidation rate of Fe2+ by the traditional oxygen oxidation method, industry has to use more agitating barrels, steam, and compressed gas, as well as a larger workshop area, which dramatically increases the equipment investment and operation costs. In this study, a strengthened oxygen oxidation method for Fe2+ using a homemade venturi jet microbubble generator is proposed. Microbubbles of air, oxygen, or oxygen-enriched air can be formed in the leaching solution or suspension, which can greatly improve the dissolved oxygen content in the solution and increase the gas-liquid contact area, thereby accelerating the oxygen oxidation rate of Fe2+ to Fe3+ and realizing the rapid iron removal of the leaching solution or suspension. By measuring the residual concentration of Fe2+ in the solution after oxidation reaction, it was found that the pump power, solution temperature, pH, concentration of Cu2+, and solution flow rate had great effects on the oxidation performance of the produced microbubble. By analyzing the images of the microbubbles and measuring the dissolved oxygen content in the solution, it is confirmed that the accelerated oxidation reaction rate of Fe2+ using the new proposed method was mainly due to the increase of the dissolved oxygen amount in the solution. Moreover, this method can significantly increase the purification depth of iron ion, expand production capacity, and decrease energy consumption.

Microstructure and characterization of LVOF sprayed aluminium oxide-13% titanium dioxide and aluminium oxide-40% titanium dioxide coatings on ASTM 316 boiler steel

Mostly common issue in power generation plant is recognised as disintegration or degradation of steels used in boilers in recent days and main causes for this type of failure are erosion, low temperature hot corrosion, high temperature hot corrosion etc. Defensive or protective coatings have been found effective to solve this problem and showed good results. Thermally sprayed coatings are widely used in various industries in boiler components such as boiler tubes, super-heater tubes, boiler walls and Induced Draft (I.D.) fans in coal fired thermal power plants, automobile system etc. The coatings produced by LVOF method show good adherence to the substrate with lower oxidation rate. In present work LVOF Sprayed Al2 O3-13%TiO2 as well as Al2 O3-40%TiO2 Coatings were deposited on ASTM316 Boiler Steel. The characterization of coating was done by SEM, X-Ray diffraction for checking the phases formed on the surface, and elemental examination of the cross-section. The surface morphology of the above said both the coatings was examined with the help of Scanning Electron Microscopy with EDAX attachment, XRD examination and the X-ray mapping. The research investigation shows that the selected feedstock and coating technique have produced the successful coatings perfectly.

Recycling MoSi2 heating elements for preparing oxidation resistant multilayered coatings

Spent MoSi2 heating elements were used to fabricate MoSi2, ZrB2/MoSi2 and MoSi2-ZrB2/MoSi2 oxidation resistant coatings via a two-step process of slurry painting and spark plasma sintering. Cracks appeared in simple MoSi2 and ZrB2/MoSi2 coatings, whilst MoSi2-ZrB2/MoSi2 coating was crack-free as CTE mismatch was reduced. Mo5Si3 and MoB diffusion layers formed under MoSi2-ZrB2 transition layer in MoSi2-ZrB2/MoSi2 coating, revealing good metallurgical combination between the substrate and coating. On one side the silica layers covering MoSi2 and ZrB2/MoSi2 coatings displayed diffused cracks after oxidation at 1773 K for 100 h, on the other side it was dense and continuous for MoSi2-ZrB2/MoSi2 coating, showing low oxidation rate constant at 1773 K. Furthermore, MoSi2-ZrB2 transition layer in MoSi2-ZrB2/MoSi2 coating possessed good short-term oxidation protective properties at 1873 and 1973 K since the formation of ZrSiO4 improved the stability of Si-O-Zr composite oxide scale and diminished the oxygen permeability, therefore demonstrating good high-temperature oxidation resistance.

Energy Expenditure, Protein Oxidation and Body Composition in a Cohort of Very Low Birth Weight Infants.

The nutritional management of preterm infants is a critical point of care, especially because of the increased risk of developing extrauterine growth restriction (EUGR), which is associated with worsened health outcomes. Energy requirements in preterm infants are simply estimated, so the measurement of resting energy expenditure (REE) should be a key point in the nutritional evaluation of preterm infants. Although predictive formulae are available, it is well known that they are imprecise. The aim of our study was the evaluation of REE and protein oxidation (Ox) in very low birth weight infants (VLBWI) and the association with the mode of feeding and with body composition at term corrected age. Methods: Indirect calorimetry and body composition were performed at term corrected age in stable very low birth weight infants. Urinary nitrogen was measured in spot urine samples to calculate Ox. Infants were categorized as prevalent human milk (HMF) or prevalent formula diet (PFF). Results: Fifty VLBWI (HMF: 23, PFF: 27) were evaluated at 36.48 ± 0.85 post-conceptional weeks. No significant differences were found in basic characteristics or nutritional intake in the groups at birth and at the assessment. No differences were found in the REE of HMF vs. PFF (59.69 ± 9.8 kcal/kg/day vs. 59.27 ± 13.15 kcal/kg/day, respectively). We found statistical differences in the protein-Ox of HMF vs. PFF (1.7 ± 0.92 g/kg/day vs. 2.8 ± 1.65 g/kg/day, respectively, p < 0.01), and HMF infants had a higher fat-free mass (kg) than PFF infants (2.05 ± 0.26 kg vs. 1.82 ± 0.35 kg, respectively, p < 0.01), measured with air displacement plethysmography. Conclusion: REE is similar in infants with a prevalent human milk diet and in infants fed with formula. The HMF infants showed a lower oxidation rate of proteins for energy purposes and a better quality of growth. A greater amount of protein in HMF is probably used for anabolism and fat-free mass deposition. Further studies are needed to confirm our hypothesis.

Fe doped Ni–Co alloy by electroplating as protective coating for solid oxide fuel cell interconnect application

To obtain higher electrical conductivity and lower area specific resistance (ASR), the 10% Fe doped Ni–Co (NCF) alloy was prepared on SUS 430 steel substrate by electroplating for solid oxide fuel cells (SOFCs) interconnects application. Then, the SUS 430 steels and NCF coated steels were oxidized at 800 °C. The microstructure and oxide phase of samples were tested by scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). These results proved that the NCF coated steel achieved the lower oxidation rate of 9.28 × 10−14 g2cm−4s−1 and ASR of 14.72 mΩ cm2.

Oxidation Experiments and Kinetics Analysis of Nuclear Graphite ET-10 by Gas Analysis and Microstructure Observation

Nuclear graphite can be used in fission and fusion systems due to its excellent nuclear performance and mechanical properties where the ability of oxidation resistance is usually concerned. Although the excellent performance of new graphite ET-10 was revealed by previous experiments regarding the accident conditions of a fission reactor, further studies are needed to oxidize the graphite under the conditions recommended by the ASTM D7542 standard. A test facility was designed and developed to oxidize the cylindrical specimen with a 10 L/min airflow. According to oxidation rates and microstructures of specimens, the chemical kinetics-controlled regime was determined as 675–750 °C, where the activation energy was obtained as 172.52 kJ/mol. The experiment results revealed the excellent ability of graphite ET-10 for oxidation resistance with lower oxidation rates and longer oxidation times compared with some mainstream graphite. The main reasons are the low contents of some impurities and the binder and the low active surface area due to the non-impregnation baking process undertaken to produce graphite with coal tar pitch coke. It should be noted that the evolution of oxidation behavior at the bottom part of the specimen (facing the airflow) was quicker than that at the upper part of the specimen. We also suggest that the abundance of oxygen supply and the good linearity of the Arrhenius plot are prerequisites of the chemical kinetics-controlled regime rather than sufficient conditions.

Compensation Effect Exhibited by Gold Bimetallic Nanoparticles during CO Oxidation.

While CO oxidation catalyzed by gold nanoparticles has been practiced academically for several decades, there are still important discoveries to be made. One area of current interest is to pair Au with another alloying metal and observe the catalytic consequences of the presence of the other metal. In this work, TiO2-supported bimetallic Au nanoparticles are alloyed with Cu, Co, Ni, Pd, and Ru and used as catalysts for CO oxidation. Two synthetic methods for the alloys are presented: a strong electrostatic adsorption (SEA) method and a sterically demanding ligand synthesis (SDLS) method which uses triphenylphosphine (TPP) as the ligand. The catalytic performance of the materials synthesized with the SEA and SDLS methods is compared in CO oxidation. The results indicate that the materials tested present an enthalpy–entropy compensation effect. Interestingly, both the enthalpy of activation, ΔH‡, and the entropy of activation, ΔS‡, generally decrease with particle size. AuCo and AuRu materials exhibit a decrease in the overall activity as compared to Au and the other Au alloys when synthesized via SEA. Au face-centered-cubic alloys AuCu, AuNi, and AuPd prepared via SEA show an improvement in activity compared to monometallic Au in our reaction conditions. In situ diffuse reflectance infrared Fourier transform spectroscopy presents two distinct regions for Au bimetallics where AuCo and AuRu show peak positions in the region of 2070–2050 cm–1, indicating a weaker interaction for AuCo and AuRu with CO when compared to that of the other alloys. For the SDLS method samples, the hypothesis is that TPP would enhance the CO oxidation rate by enhancing the charge transfer to the metallic surface. The results indicate that SDLS samples have lower CO oxidation rates and if any charge transfer occurs, it is masked by the lateral interactions of the CO π bonds and the phenyl groups of TPP.

APO\u03954 lowers energy expenditure in females and impairs glucose oxidation by increasing flux through aerobic glycolysis

BackgroundCerebral glucose hypometabolism is consistently observed in individuals with Alzheimer’s disease (AD), as well as in young cognitively normal carriers of the Ε4 allele of Apolipoprotein E (APOE), the strongest genetic predictor of late-onset AD. While this clinical feature has been described for over two decades, the mechanism underlying these changes in cerebral glucose metabolism remains a critical knowledge gap in the field.MethodsHere, we undertook a multi-omic approach by combining single-cell RNA sequencing (scRNAseq) and stable isotope resolved metabolomics (SIRM) to define a metabolic rewiring across astrocytes, brain tissue, mice, and human subjects expressing APOE4.ResultsSingle-cell analysis of brain tissue from mice expressing human APOE revealed E4-associated decreases in genes related to oxidative phosphorylation, particularly in astrocytes. This shift was confirmed on a metabolic level with isotopic tracing of 13C-glucose in E4 mice and astrocytes, which showed decreased pyruvate entry into the TCA cycle and increased lactate synthesis. Metabolic phenotyping of E4 astrocytes showed elevated glycolytic activity, decreased oxygen consumption, blunted oxidative flexibility, and a lower rate of glucose oxidation in the presence of lactate. Together, these cellular findings suggest an E4-associated increase in aerobic glycolysis (i.e. the Warburg effect). To test whether this phenomenon translated to APOE4 humans, we analyzed the plasma metabolome of young and middle-aged human participants with and without the Ε4 allele, and used indirect calorimetry to measure whole body oxygen consumption and energy expenditure. In line with data from E4-expressing female mice, a subgroup analysis revealed that young female E4 carriers showed a striking decrease in energy expenditure compared to non-carriers. This decrease in energy expenditure was primarily driven by a lower rate of oxygen consumption, and was exaggerated following a dietary glucose challenge. Further, the stunted oxygen consumption was accompanied by markedly increased lactate in the plasma of E4 carriers, and a pathway analysis of the plasma metabolome suggested an increase in aerobic glycolysis.ConclusionsTogether, these results suggest astrocyte, brain and system-level metabolic reprogramming in the presence of APOE4, a ‘Warburg like’ endophenotype that is observable in young females decades prior to clinically manifest AD.

Effect of solvent pre-treatment on the physicochemical, thermal profiles and morphological behavior of Mangifera pajang seed fat

In this work, the effect of solvent pre-treatment (hexane, petroleum ether and ethanol) on the physicochemical, thermal and morphology behavior of Mangifera pajang seed fat (MPSF) were investigated. Fat extraction was performed using Soxhlet method, and results showed that the yield, physicochemical, and crystalline structures of the MPSF were significantly (p < 0.05) influenced by the extraction solvents. Hexane gave the highest fat yield (7.67 %) with low unsaturation value (52.13 g iodine/g) compared with petroleum ether and ethanol. Hexane MPSF also had low oxidation rate (peroxide value of 1.1 mEq/g). Both non-stabilized and stabilized hexane MPSF showed a single melting endothermic peak at high temperature with onset, maximum peak and offset temperature of 16.23 ˚C-18.21 °C, 28.22 ˚C-31.25 °C and 34.85 ˚C-39.58 °C, respectively. Hexane MPSF crystallized rapidly at high temperature with single maximum peak starting at 16.51 ˚C-16.68 °C and ending at 0.23 ˚C-1.13 °C. In comparison with ethanol extract, hexane MPSF demonstrated a compact crystalline structure with a large densely packed center. Therefore, MPSF obtained from hexane presented better overall quality than those obtained from other extraction solvents. MPSF exhibited similar melting and morphological behavior to mango kernel fat and commercial cocoa butter. These results suggested that hexane was the best solvent for the extraction of MPSF. This fat also has the potential to be applied as a cocoa butter alternative fat or functional fat.

Morpho-Mineralogical and Bio-Geochemical Description of Cave Manganese Stromatolite-Like Patinas (Grotta del Cervo, Central Italy) and Hints on Their Paleohydrological-Driven Genesis

Caves are dark subsurface environments with relatively constant temperatures that allow studying bio-mineralization processes and paleoenvironmental or climate changes in optimal conditions. In the extreme and oligotrophic cave environment, manganese patinas having stromatolite-like features are uncommon. Here we provide the first detailed mineralogical, geochemical, and microbiological investigation of fine-grained and poorly crystalline MnFe stromatolite-like wall patinas formed in a deep-cave environment in Italy. These mineralizations, about 3 mm thick, consist of an alternation of Mn-layers and Fe-lenses. We show that the microbial communities' composition is dominated by Mn-oxidizing bacteria, such as Bacillus, Flavobacterium, and Pseudomonas. Our multidisciplinary investigation, integrating data from different analytical techniques (i.e., optical microscopy, SEM-EDS, μXRF, XRPD, FT-IR, Raman spectroscopy, and DNA sequencing), revealed peculiar chemical, mineralogical, and biological features: 1) A cyclical oscillation of Mn and Fe along the growth of the patinas. We propose that this oscillation represents the shift between oxic and suboxic conditions related to different phases occurring during paleo-flood events; 2) A typical spatial distribution of mineralogy and oxidation state of Mn, bacterial imprints, detrital content, and stromatolite-like morphologies along the Mn-layers. We propose that this distribution is controlled by the local hydraulic regime of the paleo-floods, which, in turn, is directly related to the morphology of the wall surface. Under less turbulent conditions, the combination of clay mineral catalysis and biological oxidation produced vernadite, a poor-crystalline phyllomanganate with a low average oxidation state of Mn, and branched columnar stromatolite-like morphologies. On the other hand, under more turbulent conditions, the sedimentation of clay minerals and microbial communities' development are both inhibited. In this local environment, a lower oxidation rate of Mn2+ favored the formation of todorokite and/or ranciéite, two compounds with a high average oxidation state of Mn, and flat-laminated or columnar stromatolite-like morphologies.