Oxidation Products Research Articles

Comparative analysis for the impacts of VOC subgroups and atmospheric oxidation capacity on O3 based on different observation-based methods at a suburban site in the North China Plain

The persistent O3 pollution in the Beijing-Tianjin-Hebei (BTH) region remains unresolved, largely due to limited comprehension of O3-precursor relationship and photochemistry drivers. In this work, intraday O3 sensitivity evolution from VOC-limited (volatile organic compound) regime in the forenoon to transition regime in the late afternoon was inferred by relative incremental reactivity (RIR) in summer 2019 at Xianghe, a suburban site in BTH region, suggesting that VOC-focused control policy could combine with stringent afternoon NOx control. Then detailed impacts of VOC subgroups on O3 formation were further comprehensively quantified by parametric OH reactivity (KOH), O3 formation potential (OFP), as well as RIR weighted value and O3 formation path tracing (OFPT) approach based on photochemical box model. O3 episode days corresponded to stronger O3 formation, depicted by higher KOH (10.4 s−1), OFP (331.7 μg m−3), RIR weighted value (1.2), and F(O3)-OFPT (15.5 ppbv h−1). High proportions of isoprene and OVOCs (oxygenated VOCs) to the total KOH and the OFPT method were demonstrated whereas results of OFP and RIR-weighted presented extra great impacts of aromatics on O3 formation. The OFPT approach captured the process that has already happened and included final O3 response to the original VOC, thus reliable for replicating VOC impacts. The comparison results of the four methods showed similarities when utilizing KOH and OFPT methods, which reveals that the potential applicability of simple KOH for contingency VOC control and more complex OFPT method for detailed VOC- and source-oriented control during policy-making. To investigate propulsion of VOC-involved O3 photochemistry, atmospheric oxidation capacity (AOC) was quantified by two atmospheric oxidation indexes (AOI). Both AOIp_G (7.0 × 107 molec cm−3 s−1, potential AOC calculated by oxidation reaction rates) and AOIe_G (8.5 μmol m−3, estimated AOC given redox electron transfer for oxidation products) were stronger on O3 episode days, indicating that AOC promoted the radical cycling initiated from VOC oxidation and subsequent O3 production. Result-oriented AOIe_G reasonably characterized actual AOC inferred by good linear correlation between AOIe_G and O3 concentrations compared to process-oriented AOIp_G. Therefore, with continuous NOx abatement, AOIe_G should be considered to represent actual AOC, also O3-inducing ability.

Maintaining the Mitochondrial Quality Control System Was a Key Event of Tanshinone IIA against Deoxynivalenol-Induced Intestinal Toxicity.

Deoxynivalenol (DON) is the one of the most common mycotoxins, widely detected in various original foods and processed foods. Tanshinone IIA (Tan IIA) is a fat-soluble diterpene quinone extracted from Salvia miltiorrhiza Bunge, which has multi-biological functions and pharmacological effects. However, whether Tan IIA has a protective effect against DON-induced intestinal toxicity is unknown. In this study, the results showed Tan IIA treatment could attenuate DON-induced IPEC-J2 cell death. DON increased oxidation product accumulation, decreased antioxidant ability and disrupted barrier function, while Tan IIA reversed DON-induced barrier function impairment and oxidative stress. Furthermore, Tan IIA dramatically improved mitochondrial function via mitochondrial quality control. Tan IIA could upregulate mitochondrial biogenesis and mitochondrial fusion as well as downregulate mitochondrial fission and mitochondrial unfolded protein response. In addition, Tan IIA significantly attenuated mitophagy caused by DON. Collectively, Tan IIA presented a potential protective effect against DON toxicity and the underlying mechanisms were involved in mitochondrial quality control-mediated mitophagy.

Efficient and Stable Tin‐Lead Mixed Perovskite Solar Cells Using Post‐Treatment Additive with Synergistic Effects

AbstractInhibiting the oxidation of Sn2+ during the crystallization process of Sn−Pb mixed perovskite film is found to be as important as the oxidation resistance of precursor solution to achieve high efficiency, but less investigated. Considering the excellent reduction feature of hydroquinone and the hydrophobicity of tert‐butyl group, an antioxidant 2,5‐di‐tert‐butylhydroquinone (DBHQ) was introduced into Sn−Pb mixed perovskite films using an anti‐solvent approach to solve this problem. Interestingly, we find that DBHQ can act as function alterable additive during its utilization. On the one hand, DBHQ can restrict the oxidation of Sn2+ during the crystallization process, facilitating the fabrication of high‐quality perovskite film; on the other hand, the generated oxidation product 2,5‐di‐tert‐butyl‐1,4‐benzoquinone (DBBQ) can functionalize as defect passivator to inhibit the charge recombination. As a result, this synergetic effect renders the Sn−Pb mixed PSC a power conversion efficiency (PCE) up to 23.0 %, which is significantly higher than the reference device (19.6 %). Furthermore, the unencapsulated DBQH‐modified PSCs exhibited excellent long‐term stability and thermal stability, with the devices maintaining 84.2 % and 78.9 % of the initial PCEs after aging at 25 °C and 60 °C for 800 h and 120 h under N2 atmosphere, respectively. Therefore, the functional alterable strategy provides a novel cornerstone for high‐performance Sn−Pb mixed PSCs.

Efficient and Stable Tin-Lead Mixed Perovskite Solar Cells Using Post-Treatment Additive with Synergistic Effects.

Inhibiting the oxidation of Sn2+ during the crystallization process of Sn-Pb mixed perovskite film is found to be as important as the oxidation resistance of precursor solution to achieve high efficiency, but less investigated. Considering the excellent reduction feature of hydroquinone and the hydrophobicity of tert-butyl group, an antioxidant 2,5-di-tert-butylhydroquinone (DBHQ) was introduced into Sn-Pb mixed perovskite films using an anti-solvent approach to solve this problem. Interestingly, we find that DBHQ can act as function alterable additive during its utilization. On the one hand, DBHQ can restrict the oxidation of Sn2+ during the crystallization process, facilitating the fabrication of high-quality perovskite film; on the other hand, the generated oxidation product 2,5-di-tert-butyl-1,4-benzoquinone (DBBQ) can functionalize as defect passivator to inhibit the charge recombination. As a result, this synergetic effect renders the Sn-Pb mixed PSC a power conversion efficiency (PCE) up to 23.0 %, which is significantly higher than the reference device (19.6 %). Furthermore, the unencapsulated DBQH-modified PSCs exhibited excellent long-term stability and thermal stability, with the devices maintaining 84.2 % and 78.9 % of the initial PCEs after aging at 25 °C and 60 °C for 800 h and 120 h under N2 atmosphere, respectively. Therefore, the functional alterable strategy provides a novel cornerstone for high-performance Sn-Pb mixed PSCs.

Analysis of oxidation products and toxic compounds in edible and blended oil during the deep-frying of french fries

Analysis of oxidation products and toxic compounds in edible and blended oil during the deep-frying of french fries

Trappc1 intrinsically prevents ferroptosis of naive T cells to avoid spontaneous autoinflammatory disease in mice.

T lymphocytes are pivotal in adaptive immunity. The role of the trafficking protein particle complex (TRAPPC) in regulating T-cell development and homeostasis is unknown. Using CD4cre -Trappc1flox/flox (Trappc1 cKO) mice, we found that Trappc1 deficiency in T cells significantly decreased cell number of naive T cells in the periphery, whereas thymic T-cell development in Trappc1 cKO mice was identical as WT mice. In the culture assays and mouse models with adoptive transfer of the sorted WT (CD45.1+ CD45.2+ ) and Trappc1 cKO naive T cells (CD45.2+ ) to CD45.1+ syngeneic mice, Trappc1-deficient naive T cells showed significantly reduced survival ability compared with WT cells. RNA-seq and molecular studies showed that Trappc1 deficiency in naive T cells reduced protein transport from the endoplasmic reticulum to the Golgi apparatus, enhanced unfolded protein responses, increased P53 transcription, intracellular Ca2+ , Atf4-CHOP, oxidative phosphorylation, and lipid peroxide accumulation, and subsequently led to ferroptosis. Trappc1 deficiency in naive T cells increased ferroptosis-related damage-associated molecular pattern molecules like high mobility group box 1 or lipid oxidation products like prostaglandin E2, leukotriene B4, leukotriene C4, and leukotriene D4. Functionally, the culture supernatant of Trappc1 cKO naive T cells significantly promoted neutrophils to express inflammatory cytokines like TNFα and IL-6, which was rescued by lipid peroxidation inhibitor Acetylcysteine. Importantly, Trappc1 cKO mice spontaneously developed severe autoinflammatory disease 4 weeks after birth. Thus, intrinsic expression of Trappc1 in naive T cells plays an integral role in maintaining T-cell homeostasis to avoid proinflammatory naive T-cell death-caused autoinflammatory syndrome in mice. This study highlights the importance of the TRAPPC in T-cell biology.

Jussara palm tree (Euterpe edulis M.) açai-berry oil performance on auto- and photo-oxidation: Minor components’ stability and evolution of volatile compounds

The oxidative stability of açai-berry oil relating with the formation of oxidation products, the stability of minor components, and the evolution of volatile compounds under accelerated auto- and photo-oxidation was investigated. In both tests, peroxide value increased linearly with time and was negatively associated (R² ≥ 0.98) with α- and β-tocopherols, and chlorophyll a. γ-Tocopherol was one of the most unstable compounds, reaching complete loss between 0-to-3 days in auto-oxidation, and between 3-to-5 days in photo-oxidation. α-Tocopherol remained stable during auto-oxidation whereas β-Tocopherol degraded from 5-to-7 days, reaching 57 % loss. At 7 days of photo-oxidation, α-Tocopherol reached a small 26 % loss and β-Tocopherol a 32 % loss. Anthocyanins content decayed exponentially with time, reaching a 93 % loss after 7 days of auto-oxidation and a complete loss between 0-to-3 days of photo-oxidation. Hexanal and nonanal were formed in the advanced stages of auto-oxidation and in early stages of photo-oxidation, reaching after 7 days of oxidation contents that were over 15-fold and over 7-fold higher in the later than in the former. Conversely, 2-heptenal was formed only in photo-oxidation. Açai-berry oil was highly stable in auto-oxidation in the dark, but it requires storage under protection from light due to its low photo-oxidation stability.

Fatty acid metabolism promotes TRPV4 activity in lung microvascular endothelial cells in pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a morbid disease characterized by significant lung endothelial cell (EC) dysfunction. Prior work has shown that microvascular endothelial cells (MVECs) isolated from animals with experimental PAH and patients with PAH exhibit significant abnormalities in metabolism and calcium signaling. With regards to metabolism, we and others have shown evidence of increased aerobic glycolysis and evidence of increased utilization of alternate fuel sources (such as fatty acids) in PAH EC. In the realm of calcium signaling, our prior work linked increased activity of the transient receptor potential vanilloid-4 (TRPV4) channel to increased proliferation of MVECs isolated from the Sugen/Hypoxia rat model of PAH (SuHx-MVECs). However, the relationship between metabolic shifts and calcium abnormalities was not clear. Specifically, whether shifts in metabolism were responsible for increasing TRPV4 channel activity in SuHx-MVECs was not known. In this study, using human data, serum samples from SuHx rats, and SuHx-MVECs, we describe the consequences of increased MVEC fatty acid oxidation in PAH. In human samples, we observed an increase in long-chain fatty acid levels that was associated with PAH severity. Next, using SuHx rats and SuHx-MVECs, we observed increased intracellular levels of lipids. We also show that increasing intracellular lipid content increases TRPV4 activity, whereas inhibiting fatty acid oxidation normalizes basal calcium levels in SuHx-MVECs. By exploring the fate of fatty acid-derived carbons, we observed that the metabolite linking increased intracellular lipids to TRPV4 activity was β-hydroxybutyrate (BOHB), a product of fatty acid oxidation. Finally, we show that BOHB supplementation alone is sufficient to sensitize the TRPV4 channel in rat and mouse MVECs. Returning to humans, we observe a transpulmonary BOHB gradient in human patients with PAH. Thus, we establish a link between fatty acid oxidation, BOHB production, and TRPV4 activity in MVECs in PAH. These data provide new insight into metabolic regulation of calcium signaling in lung MVECs in PAH.NEW & NOTEWORTHY In this paper, we explore the link between metabolism and intracellular calcium levels in microvascular endothelial cells (MVECs) in pulmonary arterial hypertension (PAH). We show that fatty acid oxidation promotes sensitivity of the transient receptor potential vanilloid-4 (TRPV4) calcium channel in MVECs isolated from a rodent model of PAH.

Corrosion behavior of precracked SiCf/SiC composites under 1200–1300°C Na2SO4‐wet‐oxygen environment

AbstractSiCf/SiC composites, as promising materials for the hot‐section components of turbine engines, are susceptible to hot corrosion due to the steam environments. Especially, under rotational and thermal stress, numerous microcracks may be generated in the SiCf/SiC ceramic matrix, which can trigger the rapid invasion of corrosive gases and deteriorate the composite mechanical properties. Therefore, it is of great importance to investigate the degradation mechanisms of SiCf/SiC with precracks existing. Here, the corrosion behavior of precracked SiCf/SiC in the Na2SO4‐wet‐oxygen environment was evaluated. By comparing mechanical evolution under different corrosion conditions, microfailure mechanisms of SiCf/SiC were revealed. The results indicate that brittle cracking of the matrix and oxidation erosion of fibers are the key factors in reducing the tensile strain of composites. Specifically, the composite damage resistance increases at 67 MPa‐1300°C. At this point, the prestress level is moderate and close to the matrix cracking limit. The prefabricated microcracks can be healed at 1300°C by liquid oxidation products, which hinders cracks bridging large‐scale. This study is conducive to a better understanding of failure mechanisms of SiCf/SiC in complex service environments.

Charged Microdroplets as Microelectrochemical Cells for CO2 Reduction and C-C Coupling.

Charged microdroplets offer novel electrochemical environments, distinct from traditional solid-liquid or solid-liquid-gas interfaces, due to the intense electric fields at liquid-gas interfaces. In this study, we propose that charged microdroplets serve as microelectrochemical cells (MECs), enabling unique electrochemical reactions at the gas-liquid interface. Using electrospray-generated microdroplets, we achieved multielectron CO2 reduction and C-C coupling to synthesize ethanol using molecular catalysts. These catalysts effectively harness and relay electrons, enhancing the longevity of solvated electrons and enabling multielectron reactions. Importantly, we revealed the intrinsic relationship between the size and charge density of a MEC and its reaction selectivity. Employing in situ mass spectrometry, we identified reaction intermediates (molecular catalyst adducts with HCOO) and oxidation products, elucidating the CO2 reduction mechanism and the comprehensive reaction procedure. Our research underscores the promising role of charged microdroplets in pioneering new electrochemical systems.

The influence of plant components on microbiological and oxidative processes in dry fish and plant products during storage

A pressing issue in the food industry is providing the population with adequate nutrition. According to the concept of healthy eating, a person needs to increase the consumption of plant foods without reducing the consumption of foods containing complete protein. We have created dry fish and plant products, in the form of food concentrates, containing all the necessary macro- and micronutrients. The purpose of the research was to study the influence of plant components on the microbiological and oxidative processes of dry fish and fish-plant products during storage. To achieve the intended goal, the tasks of determining microbiological indicators and oxidation products at the beginning and end of the storage period were solved. Storage of dry fish and plant products was carried out for 12 months in polymer packaging at a temperature of plus 20±5℃. All analyses were carried out using generally accepted standard methods. As a result of the studies, it was established that the microbiological indicators of a dry fish-plant product, due to the addition of vegetables and corn flour, were higher than those of a dry fish product (0.5x104 and 0.2x104 CFU per 1 g, respectively), but during storage the bacterial contamination of dry of fish and plant products decreased from 0.5x104 to 0.1x104 CFU per 1 g of product. Also, plant components affected the oxidative processes in dry fish and vegetable products. The acid number in samples of dry fish product increased from 0.71 to 2.67 mg of KOH, and in samples of dry fish-plant product – from 0.65 to 1.87 mg of KOH after 12 months of storage. Thus, plant components inhibited the oxidation process and maintain the quality of the product during storage.

Rational biodiesel production from oxidation stability perspective: Evaluation of lipid-soluble carbonyl compound formation in the seed oil and biodiesel with long-term storage

The exploration of appropriate feedstock and catalytic transesterification hinders the practical application of biodiesel. Here, we introduced rational biodiesel production from oxidation stability perspective and evaluated the lipid-soluble carbonyl-containing oxidation products in long-term stored biodiesel samples that prepared from different oil source, catalyst for production, and ester bond type. A stable isotope labeling method based on liquid chromatography-high resolution-mass spectrometry (SIL-LC-HRMS) detection is established using a pair of labeling reagents namely1-(2-hydrazinyl-2-oxoethyl)pyridin-1-ium chloride (GP) and [2H5]1-(2-Hydrazinyl-2-oxoethyl)pyridin-1-ium chloride ([2H5]GP) for lipid-soluble carbonyl-containing oxidation products, including aldehydes and ketones. The main benefits of SIL-LC-HRMS are its sensitivity, selectivity, and feature coverage towards carbonyl-containing compounds and realized their non-targeted screening and relative quantification from complex matrices. Using SIL-LC-HRMS analysis, it was estimated the distribution and formation of 131 carbonyl compounds in three different kinds of second-generation feedstock and biodiesels with one-year storage in the dark. Double bond equivalent (DBE)-number of carbon (nC) plots and hierarchical clustering heatmap analysis reveal the effect of the oil source, catalyst type, and alkyl ester bond type on the variance in carbonyl compound formation during long-term biodiesel storage, arguably the most crucial factor oxidation stability in rational biodiesel production. The carbonyl formation and their variations in biodiesel samples are also discussed by theoretically calculating the bond dissociation energy for the primary constituent of seed oil and biodiesel.

Dissociation constants of relevant secondary organic aerosol components in the atmosphere

The presented studies focus on measuring the determination of the acidity constant (pKa) of relevant secondary organic aerosol components. For our research, we selected important oxidation products (mainly carboxylic acids) of the most abundant terpene compounds, such as α-pinene, β-pinene, β-caryophyllene, and δ-3-carene. The research covered the synthesis and determination of the acidity constant of selected compounds. We used three methods to measure the acidity constant, i.e., 1H NMR titration, pH-metric titration, Bates-Schwarzenbach spectrophotometric method. Moreover, the pKa values were calculated with Marvin 21.17.0 software to compare the experimentally derived values with those calculated from the chemical structure. pKa values measured with 1H NMR titration ranged from 3.51 ± 0.01 for terebic acid to 5.18 ± 0.06 for β-norcaryophyllonic acid. Moreover, the data determined by the 1H NMR method revealed a good correlation with the data obtained with the commonly used potentiometric and UV-spectroscopic methods (R2 = 0.92). In contrast, the comparison with in silico results exhibits a relatively low correlation (R2Marvin = 0.66). We found that most of the values calculated with the Marvin Program are lower than experimental values obtained with pH-metric titration with an average difference of 0.44 pKa units. For di- and tricarboxylic acids, we obtained two and three pKa values, respectively. A good correlation with the literature values was observed, for example, Howell and Fisher (1958) used pH-metric titration and measured pKa1 and pKa2 to be 4.48 and 5.48, while our results are 4.24 ± 0.10 and 5.40 ± 0.02, respectively.

Photoelectrochemical Glycerol Oxidation Coupled with Hydrogen Production

AbstractThe catalytic oxidation of glycerol, a surplus byproduct of biodiesel, has received increasing attention due to the popular applications of its oxidation products, such as aldehydes, ketones, and carboxylates. Photoelectrochemical (PEC) methods provide a clean and sustainable pathway for glycerol oxidation and upgrading. However, selective oxidation of glycerol is a challenge due to its complex oxidation path, where the cleavage of C−O or C−C bonds at different positions can lead to a variety of products. This concept aims to describe the recent advances in PEC selective glycerol oxidation for the preparation of multiple high value‐added products, and discuss the reaction mechanism and selective production strategies in detail. Finally, the remaining challenges and future prospects for the PEC glycerol oxidation system are presented.

Trifluoromethylated Lithium Borates as Electrolyte Salts for High‐Energy‐Density Lithium‐Ion Batteries with High‐Voltage LiNi0.5Mn1.5O4 Positive Electrodes

AbstractLiNi0.5Mn1.5O4 (LNMO) is a promising positive electrode material for high‐energy‐density lithium‐ion batteries (LIBs) because of its high working voltage; however, its practical application is hindered by the insufficient oxidation resistance of LIB electrolytes. In this study, we aimed to address this issue by evaluating two trifluoromethylated lithium borate compounds lithium difluoro (perfluoropinacolato) borate (PFP‐F2) and lithium difluoro(2‐hydroxy‐3,3,3,3′,3′,3′‐hexafluoroisobutylato) borate (HHIB‐F2) as electrolyte salts for high‐potential LIBs (4.8 V vs. Li/Li+) with LNMO positive electrodes. In full‐cell tests, the cyclability of LIBs containing these salts is superior (60 °C) to that of the cell with lithium tetrafluoroborate (LiBF4) as the reference electrolyte salt, which is ascribed to the formation of a positive electrode passivation layer that inhibits the oxidative decomposition of the electrolyte salt and solvent in the former case. Moreover, the oxidative decomposition of trifluoromethylated borates at 4.8 V affords a passivation layer on the negative electrode. Thus, the examined borates hold great promise for the commercialization of high‐energy‐density LNMO‐based LIBs, and the formation of a solid electrolyte interphase (SEI) at the negative electrode resulting from the oxidative decomposition products of electrolyte salts is a promising new way to enhance the performance of high‐potential positive electrode LIBs beyond existing levels.

Use of NMR, FTIR and GC–MS to monitor the oxidation products of phospholipids in bighead carp head during cooking process

Bighead carp head soup is a traditional Chinese cuisine with a pleasant aroma, but the effect of fish head phospholipids (FPLs) on the odorants is not fully understood. In this study, nuclear magnetic resonance (NMR), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME–GC–MS) were used to monitor the oxidation products of phospholipids in fish head soup during the cooking process, and the fish head triglycerides (FTGs) were used as controls. In 1H NMR spectra, the signals of unsaturated acyl groups and the oxidation compounds in FPLs were significantly higher than those in FTGs. The results of FTIR showed that the changes of functional group absorptions of the oxidation compounds in FPLs were greater than FTGs. GC–MS demonstrated that FPLs samples produced more lipid-derived volatile compounds than FTGs samples. These results showed that FPLs were more prone to oxidation and could produce more lipid-derived odorants. Therefore, FPLs rather than FTGs, were the main precursor substance of lipid-derived odorants in bighead carp head soup.

CAMx–UNIPAR simulation of secondary organic aerosol mass formed from multiphase reactions of hydrocarbons under the Central Valley urban atmospheres of California

Abstract. The UNIfied Partitioning-Aerosol phase Reaction (UNIPAR) model was integrated into the Comprehensive Air quality Model with extensions (CAMx) to process secondary organic aerosol (SOA) formation by capturing multiphase reactions of hydrocarbons (HCs) in regional scales. SOA growth was simulated using a wide range of anthropogenic HCs, including 10 aromatics and linear alkanes with different carbon lengths. The atmospheric processes of biogenic HCs (isoprene, terpenes, and sesquiterpene) were simulated for major oxidation paths (ozone, OH radicals, and nitrate radicals) to predict day and night SOA formation. The UNIPAR model streamlined the multiphase partitioning of the lumping species originating from semi-explicitly predicted gas products and their heterogeneous chemistry to form non-volatile oligomeric species in both organic aerosol and inorganic aqueous phase. The CAMx–UNIPAR model predicted SOA formation at four ground urban sites (San Jose, Sacramento, Fresno, and Bakersfield) in California, United States, during wintertime 2018. Overall, the simulated mass concentrations of the total organic matter, consisting of primary organic aerosol and SOA, showed a good agreement with the observations. The simulated SOA mass in the urban areas of California was predominated by alkane and terpene oxidation products. During the daytime, low-volatility products originating from the autoxidation of long-chain alkanes considerably contributed to the SOA mass. In contrast, a significant amount of nighttime SOA was produced by the reaction of terpene with ozone or nitrate radicals. The spatial distributions of anthropogenic SOA associated with aromatic and alkane HCs were noticeably affected by the southward wind direction, owing to the relatively long lifetime of their atmospheric oxidation, whereas those of biogenic SOA were nearly insensitive to wind direction. During wintertime 2018, the impact of inorganic aerosol hygroscopicity on the total SOA budget was not evident because of the small contribution of aromatic and isoprene products, which are hydrophilic and reactive in the inorganic aqueous phase. However, an increased isoprene SOA mass was predicted during the wet periods, although its contribution to the total SOA was little.

The oxidized phospholipid PGPC impairs endothelial function by promoting endothelial cell ferroptosis via FABP3

Ferroptosis is a novel cell death mechanism that is mediated by iron-dependent lipid peroxidation. It may be involved in atherosclerosis development. Products of phospholipid oxidation play a key role in atherosclerosis. 1-palmitoyl-2-glutaroyl-sn-glycero-3-phosphocholine (PGPC) is a phospholipid oxidation product present in atherosclerotic lesions. It remains unclear whether PGPC causes atherosclerosis by inducing endothelial cell ferroptosis. In this study, human umbilical vein endothelial cells (HUVECs) were treated with PGPC. Intracellular levels of ferrous iron, lipid peroxidation, superoxide anions (O2•−), and glutathione were detected, and expression of fatty acid binding protein-3 (FABP3), glutathione peroxidase 4 (GPX4), and CD36 were measured. Additionally, the mitochondrial membrane potential (MMP) was determined. Aortas from C57BL6 mice were isolated for vasodilation testing. Results showed that PGPC increased ferrous iron levels, the production of lipid peroxidation and O2•−, and FABP3 expression. However, PGPC inhibited the expression of GPX4 and glutathione production and destroyed normal MMP. These effects were also blocked by ferrostatin-1, an inhibitor of ferroptosis. FABP3 silencing significantly reversed the effect of PGPC. Furthermore, PGPC stimulated CD36 expression. Conversely, CD36 silencing reversed the effects of PGPC, including PGPC-induced FABP3 expression. Importantly, E06, a direct inhibitor of the oxidized 1-palmitoyl-2-arachidonoyl-phosphatidylcholine IgM natural antibody, inhibited the effects of PGPC. Finally, PGPC impaired endothelium-dependent vasodilation, ferrostatin-1 or FABP3 inhibitors inhibited this impairment. Our data demonstrate that PGPC impairs endothelial function by inducing endothelial cell ferroptosis through the CD36 receptor to increase FABP3 expression. Our findings provide new insights into the mechanisms of atherosclerosis and a therapeutic target for atherosclerosis.

Study by means of 1H nuclear magnetic resonance of the oxidation process in high oleic sunflower oil and palm oil during deep-frying of fish cakes

This study aimed to compare the frying performance of palm oil (PO) and high oleic sunflower oil (HOSO) during frying aquatic products. The quality change and frying performance of HOSO and PO during frying of fish cakes were investigated. The oxidation and hydrolysis products of both oils were explored by the nuclear magnetic resonance technique. The results showed that the color deepening rate of PO was higher than that of HOSO. After 18 h of frying, the total polar compound content of PO and HOSO reached 25.67% and 27.50%, respectively. HOSO had lower degree of oxidation than PO after 24 h of continuous frying. The polyunsaturated fatty acid content in HOSO and PO significantly decreased. The oleic acid content in HOSO remained above 80% during the frying process. The major aldehydes in both oils were (E, E)-2,4-alkadienals and n-alkanals and glycerol diesters (DAGs) were abundant in PO. Furthermore, the addition of fish cakes had slight effect on the quality of the frying oil. Therefore, HOSO is an appropriate candidate for frying owing to its excellent frying stability and nutritional value.

Evaluation of meat and meat product oxidation and off-flavor formation: Managing oxidative changes

One of the primary issues with processed foods during heat treatment and freezing storage is fat oxidation, which causes significant changes in fats due to their interaction with reactive oxygen species (ROS). This interaction leads to the creation of various aldehydes that have a high affinity for large molecules, such as proteins, leading to the formation of final products of advanced oxidation processes that contribute to food spoilage. Co-oxidation can also result in extensive damage. Another problem affecting the quality and nutritional value of meat products is protein oxidation, which can occur during storage via freezing and thawing or as a result of heat treatment. Heat treatment can cause physical and chemical changes, such as the loss of some essential amino acids and the transformation of certain amino acids into carbonyl compounds via various mechanisms. Protein oxidation is indicated by the accumulation of these carbonyl compounds, and the heat treatment can lead to the denaturation of myoglobin, which is responsible for the brown color of cooked meat and is influenced by several factors. Active protein aggregates can interact with the oxidation products of polyunsaturated fatty acids and with carbohydrate glycation or glycoxidation to produce Maillard products. It is critical to understand the oxidative changes that occur in fats and proteins in food, particularly in meat products, since these components are among the primary constituents of food.