Correlations of dynamic changes in lipid and protein of salted large yellow croaker during storage.

Protein and lipid are two major components that undergo significant changes during processing of aquatic products. This study focused on the protein oxidation, protein conformational states, lipid oxidation and lipid molecule profiling of salted large yellow croaker during storage, and their correlations were investigated. The degree of oxidation of protein and lipid was time-dependent, leading to an increase in carbonyl content and surface hydrophobicity, a decrease in sulfhydryl groups, and an increase in conjugated diene, peroxide value and thiobarbituric acid reactive substances value. Oxidation caused protein structure denaturation and aggregation during storage. Lipid composition and content changed dynamically, with polyunsaturated phosphatidylcholine (PC) was preferentially oxidized compared to polyunsaturated triacylglycerol. Correlation analysis showed that the degradation of polyunsaturated key differential lipids (PC 18:2_20:5, PC 16:0_22:6, PC 16:0_20:5, etc.) was closely related to the oxidation of protein and lipid. The changes in protein conformation and the peroxidation of polyunsaturated lipids mutually promote each other's oxidation process.

Visible-light-enabled stereoselective synthesis of functionalized cyclohexylamine derivatives via [4 + 2] cycloadditions.

An unprecedented intermolecular [4 + 2] cycloaddition of benzocyclobutylamines with α-substituted vinylketones, enabled by photoredox catalysis, has been developed. The current method enables facile access to highly functionalized cyclohexylamine derivatives that were otherwise inaccessible, in moderate to good yields with excellent diastereoselectivities. This protocol has some excellent features, such as full atom economy, good functional-group compatibility, mild reaction conditions, and an overall redox-neutral process. Additionally, an asymmetric version of this cycloaddition was preliminarily investigated via the incorporation of a chiral phosphoric acid (CPA), and moderate to good enantioselectivity could be effectively realized with excellent diastereoselectivity. Synthetic applications were demonstrated via a scale-up experiment and elaborations to access amino alcohol and cyclobutene derivatives. Based on the results of control experiments, a reasonable reaction mechanism was proposed to elucidate the reaction pathway.

Effects of different curing concentrations and drying times on the microbial community structure and metabolites of dried Spanish mackerel.

Cured Spanish mackerel has a promising market owing to its nutritious nature as well as ease of transportation and preservation. However, the nutritional and flavor formation mechanism of Spanish mackerel after curing and drying is unclear. To overcome this problem, the effects of different processing conditions on the free amino acid, microbial community, and flavor of Spanish mackerel were explored. Staphylococcus and Cobetia are the main microorganisms in cured mackerel and are closely associated with the formation of their quality. Compared with fresh mackerel, cured mackerel contains increased levels of protein, fat, and chloride, contributing to its distinctive flavor. The contents of free amino acids in the BA64 group were substantially higher than those in other groups, particularly the contents of threonine, glycine, and tyrosine. These findings will contribute to the development of high-quality cured Spanish mackerel products and cured aquatic products.

Iridium-catalyzed asymmetric cascade dearomative allylation/acyl transfer rearrangement: access to chiral N-substituted 2-pyridones.

Iridium-catalyzed dearomative allylation/acyl transfer rearrangement has been developed using easily available 2-pyridinyl benzoates and vinyl ethylene carbonate. This protocol enabled the expedient synthesis of a variety of chiral N-substituted 2-pyridones in good to high yields with excellent enantioselectivity. It has the advantages of high atom economy, wide substrate scope, gram-scale synthesis, and versatile synthetic transformations.

Challenging Task of Ni-Catalyzed Highly Regio-/Enantioselective Semihydrogenation of Racemic Tetrasubstituted Allenes via a Kinetic Resolution Process.

The first earth-abundant transition metal Ni-catalyzed highly regio- and enantioselective semihydrogenation of racemic tetrasubstituted allenes via a kinetic resolution process as a challenging task was well established. This protocol furnishes expedient access to a diversity of structurally important enantioenriched tetrasubstituted allenes and chiral allylic molecules with high regio-, enantio-, and Z/E-selectivity. Remarkably, this semihydrogenation proceeded with one carbon-carbon double bond of allenes, which was regioselective complementary to the Rh-catalyzed asymmetric version. Deuterium labeling experiments and density functional theory (DFT) calculations were carried out to reveal the reasonable reaction mechanism and explain the regio-/stereoselectivity.

Multi-omics Analysis of Volatile Flavor Components in Pacific Chub and Spanish Mackerel during Freezing using GC-MS-O.

This study employed gas chromatography-mass spectrometry with olfactory (GC-MS-O) and multi-omics methods to investigate the changes in volatile flavor compounds during the freezing process of Pacific chub mackerel (Scomber japonicus) from Japan and China, and Spanish mackerel (Scomberomorus niphonius). A total of 18 volatile flavor compounds were identified, and significant differences in volatile flavor components were observed among samples frozen for 1 week, 1 year, and 2 years. The results of the Partial least squares regression (PLSR) indicated that the fishy odor was correlated with independent variables such as fatty acids (FA 22:4, FA 28:6, FA 24:4), differentially expressed genes (Gene.2425 (NDUFA5), Gene.38 (GPX1), and Gene.2844 (DAD1)). Classification and regression tree (CART) analysis revealed that the peak area values of fatty acids (FA 22:5, FA 20:4) and fatty acid esters of hydroxy fatty acids (FAHFA 18:0/22:3) were the main differentiating factors for fishy odor perception.

Primary activation of para-quinone methides by chiral phosphoric acid for enantioselective construction of tetraarylmethanes.

Demonstrated here is an asymmetric nucleophilic addition via primary activation of para-quinone methides (p-QMs) based on a chiral phosphoric acid catalytic system. In sharp contrast to previous CPA-based bifunctional activation processes that all required the nucleophiles to have an effective hydrogen bond donor unit (e.g., OH, NH), here no such unit is required in the nucleophile. N-protected indole nucleophiles were successfully utilized for the synthesis of chiral tetraarylmethanes with high efficiency and enantioselectivity under mild conditions. Therefore, this protocol significantly expanded the scope of asymmetric transformations of p-QMs.

Modular access to chiral bridged piperidine-γ-butyrolactones via catalytic asymmetric allylation/aza-Prins cyclization/lactonization sequences.

Chiral functionalized piperidine and lactone heterocycles are widely spread in natural products and drug candidates with promising pharmacological properties. However, there remains no general asymmetric methodologies that enable rapid assemble both critical biologically important units into one three-dimensional chiral molecule. Herein, we describe a straightforward relay strategy for the construction of enantioenriched bridged piperidine-γ-butyrolactone skeletons incorporating three skipped stereocenters via asymmetric allylic alkylation and aza-Prins cyclization/lactonization sequences. The excellent enantioselectivity control in asymmetric allylation with the simplest allylic precursor is enabled by the synergistic Cu/Ir-catalyzed protocol; the success of aza-Prins cyclization/lactonization can be attributed to the pivotal role of the ester substituent, which acts as a preferential intramolecular nucleophile to terminate the aza-Prins intermediacy of piperid-4-yl cation species. The resulting chiral piperidine-γ-butyrolactone bridged-heterocyclic products show impressive preliminary biological activities against a panel of cancer cell lines.

Association between Obesity and Periodontitis in US Adults: NHANES 2011-2014.

INTRODUCTION: It is controversial whether obesity and periodontitis are related. A representative US population was examined for the relationship between obesity and periodontitis. METHODS: In the National Health and Nutrition Examination Survey (NHANES) 2011-2014, participants (n = 6,662) aged 30 years or older and who underwent periodontal examinations were chosen for analysis. An assessment of obesity was based on body mass index (BMI) and waist circumference (WC). Estimates of obesity and periodontal disease were made using univariate and multivariate logistic regression models. RESULTS: According to an adjusted odds ratio (OR) for periodontitis, BMI (OR = 1.01, 95% CI: 1.01∼1.02) and WC (OR = 1.01, 95% CI: 1∼1.01) were significantly associated with periodontitis, respectively. After adjusting for confounding factors, the OR for patients with high WC with periodontitis was 1.18 (1.04∼1.33) compared to normal WC. BMI and WC subgroups showed no significant interaction (p for interaction >0.05), except for the age interaction in BMI. Among young adults aged 30-44 years, obesity was significantly associated with periodontitis in subgroups; the adjusted OR for having periodontal disease was 1.02 (1∼1.03) and 1.01 (1∼1.02) for subjects with BMI and WC, respectively. When all covariates were adjusted, BMI ≥30 kg/m2 was statistically significantly associated with prevalence of periodontal disease among people aged 30-44 years (p < 0.001). CONCLUSIONS: BMI and WC are significantly associated with periodontitis, even after adjusting for many variables, and were equally significant in obese (BMI ≥30 kg/m2) young people (30-44 years).

Copper/Ruthenium Relay Catalysis for Stereodivergent Access to δ-Hydroxy α-Amino Acids and Small Peptides.

An atom- and step-economical and redox-neutral cascade reaction enabled by asymmetric bimetallic relay catalysis by merging a ruthenium-catalyzed asymmetric borrowing-hydrogen reaction with copper-catalyzed asymmetric Michael addition has been realized. A variety of highly functionalized 2-amino-5-hydroxyvaleric acid esters or peptides bearing 1,4-non-adjacent stereogenic centers have been prepared in high yields with excellent enantio- and diastereoselectivity. Judicious selection and rational modification of the Ru catalysts with careful tuning of the reaction conditions played a pivotal role in stereoselectivity control as well as attenuating undesired α-epimerization, thus enabling a full complement of all four stereoisomers that were otherwise inaccessible in previous work. Concise asymmetric stereodivergent synthesis of the key intermediates for biologically important chiral molecules further showcases the synthetic utility of this methodology.

A Study on the Fault Location of Secondary Equipment in Smart Substation Based on the Graph Attention Network.

The inability to locate device faults quickly and accurately has become prominent due to the large number of communication devices and the complex structure of secondary circuit networks in smart substations. Traditional methods are less efficient when diagnosing secondary equipment faults in smart substations, and deep learning methods have poor portability, high learning sample costs, and often require retraining a model. Therefore, a secondary equipment fault diagnosis method based on a graph attention network is proposed in this paper. All fault events are automatically represented as graph-structured data based on the K-nearest neighbors (KNNs) algorithm in terms of the feature information exhibited by the corresponding detection nodes when equipment faults occur. Then, a fault diagnosis model is established based on the graph attention network. Finally, partial intervals of a 220 kV intelligent substation are taken as an example to compare the fault localization effect of different methods. The results show that the method proposed in this paper has the advantages of higher localization accuracy, lower learning cost, and better robustness than the traditional machine learning and deep learning methods.

Organocatalytic atroposelective synthesis of axially chiral N,N'-pyrrolylindoles via de novo indole formation.

The first organocatalytic atroposelective synthesis of axially chiral N,N'-pyrrolylindoles based on o-alkynylanilines was successfully established via de novo indole formation catalyzed by chiral phosphoric acid (CPA). This new synthetic strategy introduced CPA-catalyzed asymmetric 5-endo-dig cyclization of new well-designed o-alkynylanilines containing a pyrrolyl unit, resulting in a wide range of axially chiral N,N'-pyrrolylindoles in high yields with exclusive regioselectivity and excellent enantioselectivity (up to 99% yield, >20 : 1 rr, 95 : 5 er). Considering the potential biological significance of N-N atropisomers, preliminary biological activity studies were performed and revealed that these structurally important N,N'-pyrrolylindoles had a low IC50 value with promising impressive cytotoxicity against several kinds of cancer cell lines. DFT studies reveal that the N-nucleophilic cyclization mediated by CPA is the rate- and stereo-determining step, in which ligand-substrate dispersion interactions facilitate the axial chirality of the target products.

Synthesis of medium-sized heterocycles from oxetanes based on an allylic amination/ring-opening strategy.

The construction of medium-sized ring compounds has been a prominent research area in synthetic chemistry. In this study, we developed a tandem strategy that combines allylic amination and ring-opening of oxetanes to synthesize medium-sized heterocycles. Specifically, N-aryl oxetan-3-amines undergo allylic amination with zwitterionic π-allylpalladium, followed by intramolecular ring-opening, resulting in the formation of medium-sized heterocycles. Notably, we are able to achieve the synthesis of 7-8 membered heterocycles with moderate to good yields by employing different types of zwitterionic π-allylpalladium species.

Studies on the [4 + 2] cycloaddition and allylic substitution of indole-fused zwitterionic π-allylpalladium.

The zwitterionic π-allylpalladium species, also known as dipoles, are important synthons widely used in various reactions including cycloaddition and allylic substitution. This study reported the development of a new indole-fused zwitterionic π-allylpalladium precursor compound and its application in [4 + 2] cycloaddition and allylic substitution reactions. As a result, the synthesis of pyrrolo[3,2,1-ij]quinazolin-3-one and 7-vinyl indole compounds was achieved with moderate to good yields. Notably, the allylic substitution reaction exhibited excellent regio- and stereoselectivity.

Genome-Wide Association Analysis of Protein-Coding Variants in IgA Nephropathy.

SIGNIFICANCE STATEMENT: Genome-wide association studies have identified nearly 20 IgA nephropathy susceptibility loci. However, most nonsynonymous coding variants, particularly ones that occur rarely or at a low frequency, have not been well investigated. The authors performed a chip-based association study of IgA nephropathy in 8529 patients with the disorder and 23,224 controls. They identified a rare variant in the gene encoding vascular endothelial growth factor A (VEGFA) that was significantly associated with a two-fold increased risk of IgA nephropathy, which was further confirmed by sequencing analysis. They also identified a novel common variant in PKD1L3 that was significantly associated with lower haptoglobin protein levels. This study, which was well-powered to detect low-frequency variants with moderate to large effect sizes, helps expand our understanding of the genetic basis of IgA nephropathy susceptibility. BACKGROUND: Genome-wide association studies have identified nearly 20 susceptibility loci for IgA nephropathy. However, most nonsynonymous coding variants, particularly those occurring rarely or at a low frequency, have not been well investigated. METHODS: We performed a three-stage exome chip-based association study of coding variants in 8529 patients with IgA nephropathy and 23,224 controls, all of Han Chinese ancestry. Sequencing analysis was conducted to investigate rare coding variants that were not covered by the exome chip. We used molecular dynamic simulation to characterize the effects of mutations of VEGFA on the protein's structure and function. We also explored the relationship between the identified variants and the risk of disease progression. RESULTS: We discovered a novel rare nonsynonymous risk variant in VEGFA (odds ratio, 1.97; 95% confidence interval [95% CI], 1.61 to 2.41; P = 3.61×10 -11 ). Further sequencing of VEGFA revealed twice as many carriers of other rare variants in 2148 cases compared with 2732 controls. We also identified a common nonsynonymous risk variant in PKD1L3 (odds ratio, 1.16; 95% CI, 1.11 to 1.21; P = 1.43×10 -11 ), which was associated with lower haptoglobin protein levels. The rare VEGFA mutation could cause a conformational change and increase the binding affinity of VEGFA to its receptors. Furthermore, this variant was associated with the increased risk of kidney disease progression in IgA nephropathy (hazard ratio, 2.99; 95% CI, 1.09 to 8.21; P = 0.03). CONCLUSIONS: Our study identified two novel risk variants for IgA nephropathy in VEGFA and PKD1L3 and helps expand our understanding of the genetic basis of IgA nephropathy susceptibility.

Insight into the relationship between metabolite dynamic changes and microorganisms of sea urchin (S. intermedius) gonads during storage.

Sea urchin gonads have high nutritional value and degenerate rapidly during storage. Previous assessment of the freshness of sea urchin gonads was based on experience without valid biochemical indicators. Thus, the current study is to find biochemical indicators representing the freshness of sea urchin gonads. Results showed that the dominant genera of sea urchin gonads were changed from Psychromonas, Ralstonia, and Roseimarinus to Aliivibrio, Psychrilyobacter, and Photobacterium. The differential metabolites of sea urchin gonads were mainly produced through amino acids metabolism. Among them, GC-TOF-MS based differential metabolites had the greatest enrichment in the valine, leucine and isoleucine biosynthesis pathway, while LC-MS based differential metabolites had the greatest enrichment in the alanine, aspartate and glutamate metabolism pathway. The growth of dominant genus (Aliivibrio) had a great influence on the production of differential metabolites. These results will provide valuable information for accurately judging the freshness and shelf life of sea urchin gonads.

Enhanced batch sorting and rapid sensory analysis of Mackerel products using YOLOv5s algorithm and CBAM: Validation through TPA, colorimeter, and PLSR analysis.

This study employed the YOLOv5s algorithm to establish a rapid quality identification model for Pacific chub mackerel (S. japonicus) and Spanish mackerel (S. niphonius). Data augmentation was conducted using the copy-paste augmentation within the YOLOv5s network. Furthermore, a small object detection layer was integrated into the network structure's neck, while the convolutional block attention module (CBAM) was incorporated into the convolutional module to optimize the model. The model's accuracy was assessed through sensory evaluation, texture profile analysis, and colorimeter analysis. The findings indicated that the enhanced model achieved a mAP@0.5 score of 0.966, surpassing the original version's score of 0.953. Moreover, the improved model's params was only 7.848 M, and an average detection time of 115 ms/image (image resolution 2400 × 3200). Furthermore, sensory and physicochemical indicators are reliably distinguished between qualified and unqualified samples. The PLSR model exhibited R2X, R2Y, and Q2 values of 0.977, 0.956, and 0.663, respectively.

Lipidomics reveals the relationship between lipid oxidation and flavor formation of basic amnio acids participated Low-Sodium cured large yellow croaker.

The effects of basic amino acids on lipid oxidation and the formation of volatile compound in low-sodium cured large yellow croaker were investigated. Basic amino acids contribute a lot in inhibiting the degradation of phospholipids, especially l-lysine. Lipid oxidation was also inhibited by basic amino acids, and the total oxidation of groups could be sorted as low-sodium (LS) > control (C) > l-Histidine participated LS group (LS-His) > l-Arginine participated LS group (LS-Arg) > l-lysine participated LS group (LS-Lys). PC 18:1/20:5, PC 16:0/18:1, triacylglycerol (TG) 16:1/20:5/22:6, etc., were found to be key differential lipid metabolites, and 1-propanol, 2-methyl, gamma-hexalactone, etc. were recognized as key differential volatile compounds. The results of correlation analysis showed that alcohols and esters were positively correlated with TG molecules composed of saturated fatty acids and monounsaturated fatty acids. These findings provided new insights into the relationship between flavor formation and the degradation and oxidation of lipids.

Rapid screening of sensory attributes of mackerel using big data mining techniques and rapid sensory evaluation methods.

The present study aimed to investigate the potential of big data mining technology in conjunction with rapid sensory evaluation methods for the swift screening of sensory attributes of three kinds of frozen mackerel. Specifically, two rapid sensory evaluation methods, namely ideal profile method (IPM) and check-all-that-apply (CATA), were implemented and compared with the conventional descriptive analysis method. The results revealed that eight sensory attributes based on consumer network evaluations demonstrated significant consistency during the training process (p < .05). Notably, the application of web-based sensory attributes yielded highly comparable results between IPM and traditional descriptive analysis (0.915). Moreover, the results of the IPM preference map were in closer agreement with those of traditional descriptive analysis. While traditional sensory evaluation boasts high accuracy and a greater ability to detect nuances, the evolution of sensory evaluation technology has shifted its focus toward consumers. Rapid sensory evaluation analysis technology supports the collection of information directly from consumers, even by untrained or semi-trained groups, thereby presenting broad prospects for product qualitative analysis.