Final Oxidation Products Research Articles

Photocatalysis of Adsorbed Catechol on Degussa P25 TiO2 at the Air-Solid Interface.

Semiconductor photocatalysis with commercial TiO2 (Degussa P25) has shown significant potential in water treatment of organic pollutants. However, the photoinduced reactions of adsorbed catechol, a phenolic air pollutant from biomass burning and combustion emissions, at the air-solid interface of TiO2 remain unexplored. Herein we examine the photocatalytic decay of catechol in the presence of water vapor, which acts as an electron acceptor. Experiments under variable cut-off wavelengths of irradiation (λcut-off ≥ 320, 400, and 515 nm) distinguish the mechanistic contribution of a ligand-to-metal charge-transfer (LMCT) complex of surface chemisorbed catechol on TiO2. The LMCT complex injects electrons into the conduction band of TiO2 from the highest occupied molecular orbital of catechol by visible light (≥2.11 eV) excitation. The deconvolution of diffuse reflectance UV-visible spectral bands from LMCT complexes of TiO2 with catechol, o-semiquinone radical, and quinone and the quantification of the evolving gaseous products follow a consecutive kinetic model. CO2(g) and CO(g) final oxidation products are monitored by gas chromatography and Fourier-transform infrared spectroscopy. The apparent quantum efficiency at variable λcut-off are determined for reactant loss (Φ- TiO2/catechol = 0.79 ± 0.19) and product growth ΦCO2 = 0.76 ± 0.08). Spectroscopic and electrochemical measurements reveal the energy band diagram for the LMCT of TiO2/catechol. Two photocatalytic mechanisms are analyzed based on chemical transformations and environmental relevance.

Syntheses of AlLB14(L=Li or Na) crystals using alkali fluorides and its properties

AlLB14 (L=Li or Na or K) crystals were grown using LiF or NaF or KF and crystalline boron powders as the starting materials using a high-temperature Al melt at soaking temperature 1573 ∼ 1773 K for a soaking time of 5 h under an Ar atmosphere. AlLiB14 and AlNaB14 crystals were obtained from LiF or NaF and B powders, and the atomic ratios (n=B/L = 2.0 ∼ 4.0) of starting materials. The AlKB14 crystal was not obtained from KF and B powders as starting materials. The micro-Vickers hardness of AlLB14 crystals is 24(±1) GPa for AlLiB14 and 25(±1) GPa for AlNaB14. The oxidation initiation temperature of AlLiB14 was about 815 K, and the peak due to the exothermic reaction was about 960 K for AlLiB14 and about 990 K for AlNaB14. The final oxidation products were Li2B2O4, Al4B2O9, B2O3, and amorphous phases. The values for the electrical resistivity of the AlLB14 compound were 2.4 ∼ 157 Ω·cm.

Strontium Isotopic Variations of Authigenic Calcite in Clastic Strata Record Its Sediment Provenance and Fluid−Rock Interactions

Abstract Strontium isotopes of authigenic carbonate potentially record sediment provenance, fluid sources, and fluid–rock interactions, little was studied on this topic in clastic strata. This study investigated clastic rocks containing authigenic calcite in the Lower Triassic Baikouquan Formation in the Junggar Basin, northwestern China. Mineral compositional and fluid inclusion analyses were conducted to constrain the precipitation processes of authigenic calcite, and the Sr contents and isotope ratios of the calcite were also measured. The authigenic calcite was precipitated at 80–140°C as the final product of thermochemical oxidation of hydrocarbons and thus has high Mn contents and highly negative δ13CVPDB values (as low as −70‰). The calcite also exhibits anomalously low 87Sr/86Sr values (0.704827, 0.706612), which are lower than contemporaneous seawater and published 87Sr/86Sr values of carbonate cements in clastic sediments, and also much lower than 87Sr/86Sr values (0.722027, 0.736750) of alkali feldspar in the strata. These low 87Sr/86Sr values record the low 87Sr/86Sr of the dominant rocks in the provenance area, such as volcanic rocks. During diagenesis, especially mesodiagenesis, the charging of hydrocarbon-bearing fluids promoted abundant dissolution of orthoclase in the alkali feldspar detritus, releasing radiogenic 87Sr into the pore waters, and eventually increasing the 87Sr/86Sr values in the late-stage calcite that precipitated after this reaction. This inference is consistent with the positive correlation between the calcite 87Sr/86Sr ratios and the dissolution intensity of orthoclase. In regions that do not undergo hydrocarbon-charging and where orthoclase remains stable, the lower 87Sr/86Sr ratios of the calcite generally record the provenance. For authigenic calcite associated with intense fluid–rock interactions, the higher 87Sr/86Sr ratios reflect the enhanced dissolution intensity of 87Sr-rich minerals such as orthoclase. Therefore, combined with a petrological study, Sr isotopes of authigenic carbonate in clastic sediments can trace sediment provenance and intensity of fluid–rock interactions.

Clumped and in situ carbon and oxygen isotopes of calcite as tracers for oxidation of hydrocarbons in deep siliciclastic strata

The oxidation of hydrocarbons, including methane, is part of interrelated hydrogeochemical reactions affecting the carbon budget in Earth’s crust. To investigate these processes in deep siliciclastic strata, we analyzed core samples from Lower Triassic red beds in the Mahu Sag (Junggar Basin, northwest China) by coupling petrological observations with high-resolution in situ secondary ion mass spectroscopy stable carbon and oxygen isotope analyses and clumped isotopes (Δ47) of authigenic calcite. The strata contain variable oil and gas content as well as abundant high-valence Fe and/or Mn oxides. Three sequential generations of cement occur, which are characterized as (1) non-luminescent, early diagenetic calcite (MnO <0.3%, δ13CVPDB [Vienna Peedee belemnite] = −5.6‰ to −4.1‰); (2) bright-orange luminescent late-stage I calcite (0.75%−5.23% MnO, δ13C = −51.4‰ to −25.8‰); and (3) dull-orange late-stage II calcite (4.10%−12.93% MnO, δ13C = −91.4‰ to −30.9‰). Clumped isotopic thermometry reveals that the calcite precipitation temperature increases successively from <40 °C, to 81−107 °C, to finally 107−132 °C, corresponding to three precipitation time periods: before the Late Triassic, from the Early Jurassic to the Early Cretaceous, and from the Early Cretaceous to the present, respectively. δ13C values of −55.7‰ to −25.8‰ indicate that late-stage I calcite is the final product of oxidation of both methane and C2+ hydrocarbons, whereas δ13C values as low as −91‰ indicate that late-stage II calcite is mainly derived from the thermochemical oxidation of methane (δ13C = −46.8‰ to −39.3‰) induced by high-valence Mn and/or Fe oxides. For late-stage I calcite, hydrocarbon oxidation was most likely promoted by high temperatures, although microbial oxidation cannot be completely ruled out. The higher precipitation temperature of late-stage II calcite demonstrates that the oxidation of methane requires higher activation energies than oxidation of C2+ hydrocarbons. We provide reliable geochemical evidence for thermally induced sequential oxidation of hydrocarbons within deep siliciclastic strata.

Association Between Serum Uric Acid Level and the Severity of Parkinsons Disease: A cross sectional study

Background: Parkinson’s disease is a chronic, progressive, neurodegenerative disease. Various factors have been attributed to the development and progression of the diseaseover the years. Uric acid is the final oxidation product of purine metabolism with potent antioxidant properties, which could play an important role in reducing the risk of development of Parkinson’s disease (PD) as well as it could have a role in delaying the progression of Parkinson’s disease (PD). Aim: This study aims at evaluating the role of serum uric acid level in clinical progression of Parkinson’s disease. Methods: This cross-sectional study was conducted among 70 patients of Parkinson’s disease attending the outpatient department and meeting the inclusion criteria. All the clinical and biochemical data were collected and analyzed by SPSS. Mean serum uric acid levels were compared between different stages of Parkinson’s disease. A p value of less than 0.05 was considered as significant. Result: Mean age of the patients with Parkinson’s disease was 62.25 ± 8.56 years with a male to female ratio of 1.12:1. Regarding the clinical presentation of the patients, it was observed that 16 (22.9%) patients had combination of tremor, hypokinesia, rigidity and postural imbalance, 18 (25.7%) had tremor, hypokinesia & rigidity and 36 (51.4%) had tremor and rigidity. It was observed that 24.3% of the patients had sensory, sleep and cognitive disorder, 21.4% patients had sleep and cognitive disorder, 2.9% patient had disorder in sleep and anosmia, 8.6% patients had only sleep disturbance, 17.1% had only cognitive disturbance but 25.7% had no non-motor symptoms. Majority (61.4%) patient’s disease duration was 1-5 years. The mean duration of disease was found 6.34±5.53 years. Majority 34 (48.6%) patients were in stage II, 19 (27.1%) were in stage III, 5 (10.0%) were in stage IV and 12 (17.1%) were in stage V. Mean serum uric acid was found to be 3.45±1.26mg/dL (2.0-5.8) in male and 3.36±0.81mg/dL(2.1-5.8) in female patients.Serum uric acid level steadily reduced with the severity of PD which is statistically significant. Advanced stages of parkinson’s disease were associated with significantly lower levels of serum uric acid. The difference between the stages were statistically significant (p=0.007). Conclusion: This study shows a negative association between serum uric acid level and the severity of Parkinson’s disease. The level of serum uric acid decreased with the disease progression. This study added evidence consistent with an association between serum uric acid level and the severity of Parkinson’s disease. This finding pushes us to emphasize on the role of uric acid levels on the Parkinson’s disease. Bangladesh Crit Care J March 2024; 12 (1): 18-24

Impact of fission product (Ce, Sn, Sr, Se) oxides on UO2 oxidation to U3O8

In order to investigate the impact of fission products on the oxidation of spent fuel in the cladding separation process, the oxidation behavior and kinetic mechanism of UO2 and impact of M (M = Ce, Sn, Sr, Se) oxides on the oxidation of UO2 to U3O8 were investigated by TG/DSC, XRD, FT-IR and Raman. It was found that the oxidation of UO2 to U3O8 went through two stages: UO2→U3O7; U3O7→U3O8. Doping M oxide in UO2 could not change the two-step mechanism, and significantly inhibited the formation of U3O8. The final products of CeO2 and SrO-doped UO2 oxidation contained 20% U3O7 and 47% U3O7, respectively. The doping of M oxide increased the onset oxidation temperature of the two oxidation stages of UO2 by 5–65 °C. In addition, the kinetic mechanism of UO2 oxidation was investigated and found that the first and second oxidation stages were controlled by 1st order reaction or nucleation and growth, and 2nd order reaction, respectively. The doping of M oxide significantly affected the kinetic mechanism of the first stage.

Air stability and composition evolution in van der Waals Fe3GeTe2

Layered two-dimensional ferromagnetic materials have emerged as a promising platform for spintronic applications, owing to their extraordinary physical properties. Remarkably, the representative two-dimensional ferromagnet Fe3GeTe2 has been extensively investigated due to its high Curie temperature and strong perpendicular magnetic anisotropy, which are beneficial for high-density storage at room temperature. However, there are few reports on its stability in the air and the surface oxidation products, which may prohibit its future application. Here, we report the natural oxidation process of Fe3GeTe2 films grown by molecular beam epitaxy evolved in the atmosphere, which was studied by x-ray photoelectron spectroscopy measurements and transmission electron microscopy. Our research shows that the surface of the Fe3GeTe2 film is oxidized quickly when exposed to air and shows two obviously evolving stages in the whole oxidation process. In the first stage, metallic Ge atoms are almost completely oxidized to form Ge–O bonds in GeO2, while partial metallic Fe and Te atoms are oxidized into Fe2O3 and TeO2, respectively. The second stage of oxidation is dominated by changes in the valence state of the Fe element, where Fe2O3 is reduced to FeCO3 through the participation of carbon adsorbed on the surface with the final oxidation product of FeCO3 · GeO2 · TeO2. Our findings provide insight into the subsequent growth and protection of Fe3GeTe2 thin films, which is of great significance for in-depth study and further application of spintronic devices in two-dimensional limits.

Tl7]7- Clusters in Mixed Alkali Metal Thallides Cs7.29K5.71Tl13 and Cs3.45K3.55Tl7.

Investigations in the ternary system Cs-K-Tl resulted in the unexpected formation of new ternary thallides Cs7.29K5.71Tl13 and Cs3.45K3.55Tl7. Single crystal X-ray structure analyses of both compounds reveal the presence of isolated Tl cluster units. Cs7.29K5.71Tl13 crystallizes in the monoclinic space group C2/c (a = 30.7792(9) Å, b = 11.000(2) Å, c = 14.0291(4) Å, β = 112.676(4)°, Z = 4) and contains [Tl6]6- and [Tl7]7- clusters as thallium subunits. Cs3.45K3.55Tl7 crystallizes in the tetragonal space group I41/a (a = 13.6177(2) Å, c = 25.5573(8) Å, Z = 8) and contains [Tl7]7- clusters exclusively. The formation of Cs7.29K5.71Tl13 is obtained after slow cooling in addition to that of Cs3.45K3.55Tl7 and can be suppressed by quenching the stoichiometric mixture. First dissolution experiments in liquid ammonia suggest thallium and amide as final oxidation products. Full relativistic band structure calculations of Cs4K3Tl7 and Cs8K5Tl13 showed a (pseudo) band gap around EF for both compounds.

Cholesteryl Hemiazelate Present in Cardiovascular Disease Patients Causes Lysosome Dysfunction in Murine Fibroblasts.

There is growing evidence supporting the role of fibroblasts in all stages of atherosclerosis, from the initial phase to fibrous cap and plaque formation. In the arterial wall, as with macrophages and vascular smooth muscle cells, fibroblasts are exposed to a myriad of LDL lipids, including the lipid species formed during the oxidation of their polyunsaturated fatty acids of cholesteryl esters (PUFA-CEs). Recently, our group identified the final oxidation products of the PUFA-CEs, cholesteryl hemiesters (ChE), in tissues from cardiovascular disease patients. Cholesteryl hemiazelate (ChA), the most prevalent lipid of this family, is sufficient to impact lysosome function in macrophages and vascular smooth muscle cells, with consequences for their homeostasis. Here, we show that the lysosomal compartment of ChA-treated fibroblasts also becomes dysfunctional. Indeed, fibroblasts exposed to ChA exhibited a perinuclear accumulation of enlarged lysosomes full of neutral lipids. However, this outcome did not trigger de novo lysosome biogenesis, and only the lysosomal transcription factor E3 (TFE3) was slightly transcriptionally upregulated. As a consequence, autophagy was inhibited, probably via mTORC1 activation, culminating in fibroblasts' apoptosis. Our findings suggest that the impairment of lysosome function and autophagy and the induction of apoptosis in fibroblasts may represent an additional mechanism by which ChA can contribute to the progression of atherosclerosis.

Survey on Antioxidants Used as Additives to Improve Biodiesel’s Stability to Degradation through Oxidation

A major problem that limits the use of biodiesel is maintaining the fuel at the specified standards for a longer period. Biodiesel oxidizes much more easily than diesel, and the final oxidation products change its physical and chemical properties and cause the formation of insoluble gums that can block fuel filters and the supply pipes. This instability of biodiesel is a major problem and has not yet been satisfactorily resolved. Recently, the use of biodiesel has increased quite a lot, but the problem related to oxidation could become a significant impediment. A promising and cost-effective approach to improving biodiesel’s stability is to add appropriate antioxidants. Antioxidants work better or less effectively in different biodiesel fuels, and there is no one-size-fits-all inhibitor for every type of biodiesel fuel. To establish a suitable antioxidant for a certain type of biodiesel, it is necessary to know the chemistry of the antioxidants and factors that influence their effectiveness against biodiesel oxidation. Most studies on the use of antioxidants to improve the oxidative stability of biodiesel have been conducted independently. This study presents an analysis of these studies and mentions factors that must be taken into account for the choice of antioxidants so that the storage stability of biodiesel fuels can be improved.

Immunological Reactivity and Intensity of Oxidative Stress in Stable Coronary Artery Disease

The aim. To analyze the relationship between immune response factors and the intensity of oxidation of lipoproteins and proteins in patients with stable coronary artery disease (CAD) to clarify the pathogenesis of coronary atherosclerosis.
 Materials and methods. A total of 179 patients with stable CAD of II-IV functional class, mean age 56 (49-62) years (main group) and 30 healthy individuals, mean age 49 (45-53) years (control group) were examined. The material for immunological research was peripheral venous blood. To determine the indicators of immunity, flow laser cytometry and enzyme-linked immunosorbent assay were used. Spectrophotometric and fluorometric methods were used to determine the levels of intermediate and final oxidation products of lipids and proteins, as well as antioxidant protection enzymes in the blood serum and in atherogenic lipoproteins.
 Results. A direct relationship between the activity of lipoprotein peroxidation and protein oxidation with a cell-type immune response and immune inflammation was revealed.
 Conclusions. The high intensity of lipid peroxidation and protein oxidation in patients with stable CAD (stable angina pectoris) is combined with significant activation of the T-cell component of the immune response (in terms of the ratio of helper and cytotoxic subpopulations of T-lymphocytes, high concentrations of pro-inflammatory cytokines, the state of the CD40/CD40L system, the level of expression of the CD95 apoptosis marker on cells), which indicates interdependence of T-cell immunity and oxidative stress in the pathogenesis of atherosclerosis. The dependence of the hyperproduction of pro-inflammatory cytokines by mononuclear blood cells on free radical oxidation of proteins, peroxidation of apoB proteins and the intensity of antiperoxide protection (catalase and superoxide dismutase enzymes) in patients with stable CAD indicates a contribution to the presence of oxidative stress and the development of immune inflammation. A comprehensive study of the factors of immunological reactivity, the violation of which can lead to the development of immunopathological reactions, and the intensity of oxidation of lipoproteins and proteins in patients with stable CAD helps to clarify the pathogenetic relationship between chronic immune inflammation, endothelial dysfunction and oxidative stress, and also substantiates the expediency of general therapeutic approaches to the treatment of CAD.

Preparation of bimodal mesoporous CoCe composite oxide for ethanol complete oxidation in air

Abstract The CeO2 and CeCoO composite oxide catalysts with bimodal mesopore structures were prepared by hard-template method and used for ethanol complete oxidation in air. The physicochemicalphysicochemical properties of the prepared catalysts were characterized by XRD, BET, TEM, XPS, H2-TPR, and O2-TPD. The Co species can be dissolved into CeO2 lattice to form Ce–O–Co solid solution, which promotes reactive oxygen species to be formed on the prepared CeCoO oxide catalysts surface. The bimodal mesopore structures can be obtained by the used hard-template method, and the pore structures of the prepared CeCoO oxide catalysts can be affected by the introduction of Co species. The synergistic effects from bimodal mesopore structures and reactive oxygen species can effectively boost ethanol complete oxidation to final product CO2. The CeCo2 catalyst with Ce/Co mole ratio of 2.0 exhibites superior ethanol complete oxidation activity and service stability, the ethanol oxidation conversion and final oxidation product CO2 selectivity reached 99.8 % and 99.2 % at 200 °C, respectively. This work indicates that the bimodal mesoporous CeCoO solid solution composite oxide catalyst is a promising candidate for OVOCs oxidation elimination from air.

Use of Biomass Glycerol as a Reducing Agent for Photocatalytic Deprotection of Pyridine N-Oxides in an Aqueous Suspension of Titanium(IV) Oxide.

Deprotection of pyridine N-oxides under mild conditions with an inexpensive and environmentally friendly reducing reagent is an important chemical procedure. The use of biomass waste as the reducing reagent, water as the solvent and solar light as the energy source is one of the most promising approaches with minimal impact on the environment. Therefore, a TiO2 photocatalyst and glycerol are suitable components of this type of reaction. Stoichiometric deprotection of pyridine N-oxide (PyNO) with a minimal amount of glycerol (PyNO:glycerol= 7 : 1) was achieved, with only CO2 being produced as the final oxidation product of glycerol. The deprotection of PyNO was thermally accelerated. Under solar light, the temperature of the reaction system increased to 40-50 °C and PyNO was also quantitatively deprotected, indicating that solar energy, i. e., UV light and thermal energy, can be effectively used. The results provide a new approach in the fields of organic chemistry and medical chemistry using biomass waste and solar light.

REVIEW ARTICLE ON HYPERURICAEMIA WITH AN APPROACH TO VATASHONITAM

Hyperuricaemia is the condition in which Serum uric acid level is elevated in blood above 7mg/dl for men and above 6mg/dl for women. Uric acid is formed when the body breaks down a chemical called Purines. The most amount of Uric acid dissolves in the blood, passes through the kidneys, and leaves the body. Uric acid is the final oxidation product of Purine degradation. Approximately 70% of the uric acid excreted by humans comes from endogenous production and food consumption, and the remaining 20% being primarily eliminated by the intestine. The elevated Serum uric acid level is because of either increased production, or decreased excretion of uric acid, or as a combination of both processes. Urate production is accelerated by Purine rich diet, Endogenous purine production, and error in Purine metabolism.

Thermophysical properties and oxidation behaviour of the U0.8Zr0.2N solid solution

Thermophysical properties and oxidation behaviour of the composite pellet UN–20 vol%ZrN were investigated experimentally and compared with the behaviour of the pure UN pellet. A compound of a single phase, a solid solution of the average composition U0.8Zr0.2N, was obtained by Spark Plasma Sintering (SPS) of the powders UN and ZrN. Crystallographic and microstructural characterisation of the composite was performed using Scanning Electron Microscopy (SEM), standardised Energy Dispersive Spectroscopy (EDS) and Electron Backscatter Diffraction (EBSD). Nano hardness and Young’s modulus were also measured by the nanoindentation method. High-Temperature X-ray diffraction (XRD) was applied to obtain the lattice expansion as a function of temperature (room temperature to 673 K). Thermogravimetric Analysis (TGA) was applied to evaluate oxidation behaviour in air. Results demonstrate that the fabrication method results in a matrix of solid solution with homogeneous composition averaged to U0.8Zr0.2N. The mechanical properties of such solution are uniform, with variation only due to the crystallographic orientation of the grains of the solution phase, similar to pure UN. The obtained value for the average linear thermal expansion coefficient is α¯ = 7.94 × 10-6/K, which compares well to UN (α¯ = 7.95 × 10-6/K) for the same temperature range. The degradation behaviour of the composite pellet UN-20 vol%ZrN in air shows a lower oxidation onset temperature, compared to pure UN, with the final product of oxidation being mainly U3O8. Smaller crystallites in the product of corrosion of the composite pellet indicate that the mechanism of degradation of the solid solution phase U0.8Zr0.2N is accompanied by the formation of two distinct oxides and their interaction.

Oxidation of designed model peptides containing methionine, proline and glutamic acid investigated by tandem mass spectrometry and IRMPD spectroscopy

Oxidation by OH radicals produced by γ-radiolysis of single amino acids proline and glutamic acid accompanied by a series of Met-containing model peptides were investigated by a combined study of tandem mass spectrometry and infrared multiple-photon dissociation spectroscopy in the fingerprint region. The thioether group of methionine has been identified as a common target of OH free radicals leading to a S+ radical cation, which made a 2-center-three electron (2c-3e) bond with any atom having having a lone pair of electrons. However, the final fate of these 2c-3e free radicals is still unknown. These studies led to the identification of the final stable products of oxidation and the localization of the modified sites. We show that the final products contain mostly methionine sulfoxide, whatever the structure of the preceding free radical. Although the distance between two Met residues controls the nature of free radicals formed in the peptides, it has no significant effect on the final products of oxidation. These results thus confirm that the final products are not controlled by free radical structure. Also, although no proline free radical was detected previously, we show that proline residue can be oxidized.

TiO2/g-C3N4 Visible-Light-Driven Photocatalyst for Methylene Blue Decomposition

In this work, graphitic carbon nitride (g-C3N4)/titanium dioxide (TiO2) nanoparticles with heterostructures were synthesized in situ from a mixture of melamine and peroxo-titanium complexes in a calcination process. The TiO2 nanoparticles are well-dispersed on the g-C3N4 nanosheets. The prepared TiO2/g-C3N4 composites have a heterostructure and excellent photocatalytic activity for decomposing methylene blue (MB) under visible light irradiation. The as-obtained g-C3N4 embroiled with TiO2 has a much larger surface area than its components (66.7 and 6.6 m2·g−1 for TiO2 and g-C3N4 against 95.5–143.8 m2·g−1 for the composite, respectively). It enhances the separation of photo-generated charge carriers. The TiO2/g-C3N4 photocatalytic degradation of MB was investigated in aqueous heterogeneous suspensions. The experimental kinetic data for the photocatalytic process follow the pseudo-first-order kinetic model. Furthermore, TiO2/g-C3N4 retains high photocatalytic activity after four reaction cycles. In addition to prompt removal of the color, the TiO2/g-C3N4 photocatalyst can oxidize MB almost completely to final oxidation products. The pathway of MB decomposition was also addressed. Additionally, the TiO2/g-C3N4 photocatalytic system was employed to eliminate other typical organic pigments, such as malachite green, methyl blue, and methyl red. The TiO2/g-C3N4 material, with remarkable dye degradability, is a promising catalyst in industrial textile treatment and can find applications in light-harvesting systems.

The chemistry of Mandelin’s test for strychnine

Strychnine reacts with Mandelin’s reagent giving a violet-blue colouration which changes to orange-red and finally to yellow. The chromic acid test for strychnine was surpassed by Mandelin’s assay due to better reagent stability, lower detection limits and fewer false positives. The reagent is ammonium metavanadate in sulphuric acid. In this communication we provide the reaction route and the mechanism of each step, from the alkaloid to the complex final oxidation product. Several oxidations take place and the vanadic acid formed in situ is reduced to vanadous acid. Some information related to vanadium and vanadium compounds is given in order to understand the reactivity of the involved compound.

Revealing insights into the correlations between structure and performance of CrOx monometallic oxide for Hg0 capture

This study explored the impacts of the synthesis methods on the Hg0 elimination ability of CrOx adsorbents. In the sample series, the adsorbent prepared using the sol-gel method (labeled as Cr(S)) presented the best Hg0 capture performance; its Hg0 removal efficiency stayed above 88% at 150 and 200 °C and even rose to ∼97% at 250 °C in the entire 5-h Hg0 capture process. The presence of bountiful surface acid sites aided the sufficient adsorption of Hg0 and an enhancement in the oxidizability primarily accelerated the subsequent Hg0 oxidation step, which constituted the central reason for the satisfactory Hg0 capture capability of Cr(S). The Mars-Maessen mechanism assisted in understanding the Hg0 capture process over Cr(S), in which chemisorption was dominant with Cr6+ and Oα serving as the active sites and HgO formed as the final oxidation product.

Plastidic membrane lipids are oxidized by a lipoxygenase in Lobosphaera incisa.

Green microalgae can accumulate neutral lipids, as part of a general lipid remodeling mechanism under stress such as nitrogen starvation. Lobosphaera incisa is of special interest because of its unique TAG acyl chain composition, especially 20:4 (n-6) can reach up to 21% of dry weight after nitrogen starvation. In order to identify factors that may influence the accumulation of polyunsaturated fatty acids (PUFAs), we identified recently a linoleate 13-lipoxygenase (LiLOX). It shares highest identity with plastidic enzymes from vascular plants and is induced upon nitrogen starvation. Here, we confirmed the localization of LiLOX in the stroma of plastids via transient expression in epithelial onion cells. In order to further characterize this enzyme, we focused on the identification of the endogenous substrate of LiLOX. In this regard, an ex vivo enzymatic assay, coupled with non-targeted analysis via mass spectrometry allowed the identification of MGDG, DGDG and PC as three substrate candidates, later confirmed via in vitro assays. Further investigation revealed that LiLOX has preferences towards the lipid class MGDG, which seems in agreement with its localization in the galactolipid rich plastid. Altogether, this study shows the first characterization of plastidic LOX from green algae, showing preference for MGDGs. However, lipidomics analysis did neither reveal an endogenous LiLOX product nor the final end product of MGDG oxidation. Nevertheless, the latter is a key to understanding the role of this enzyme and since its expression is highest during the degradation of the plastidic membrane, it is tempting to assume its involvement in this process.