Metabolic Syndrome and Risk of Amyotrophic Lateral Sclerosis: Insights from a Large-Scale Prospective Study.

OBJECTIVE: Although metabolic abnormalities are implicated in the etiology of neurodegenerative diseases, their role in the development of amyotrophic lateral sclerosis (ALS) remains a subject of controversy. We aimed to identify the association between metabolic syndrome (MetS) and the risk of ALS. METHODS: This study included 395,987 participants from the UK Biobank to investigate the relationship between MetS and ALS. Cox regression model was used to estimate hazard ratios (HR). Stratified analyses were performed based on gender, body mass index (BMI), smoking status, and education level. Mediation analysis was conducted to explore potential mechanisms. RESULTS: In this study, a total of 539 cases of ALS were recorded after a median follow-up of 13.7 years. Patients with MetS (defined harmonized) had a higher risk of developing ALS after adjusting for confounding factors (HR: 1.50, 95% CI: 1.19-1.89). Specifically, hypertension and high triglycerides were linked to a higher risk of ALS (HR: 1.53, 95% CI: 1.19-1.95; HR: 1.31, 95% CI: 1.06-1.61, respectively). Moreover, the quantity of metabolic abnormalities showed significant results. Stratified analysis revealed that these associations are particularly significant in individuals with a BMI <25. These findings remained stable after sensitivity analysis. Notably, mediation analysis identified potential metabolites and metabolomic mediators, including alkaline phosphatase, cystatin C, γ-glutamyl transferase, saturated fatty acids to total fatty acids percentage, and omega-6 fatty acids to omega-3 fatty acids ratio. INTERPRETATION: MetS exhibits a robust association with an increased susceptibility to ALS, particularly in individuals with a lower BMI. Furthermore, metabolites and metabolomics, as potential mediators, provide invaluable insights into the intricate biological mechanisms. ANN NEUROL 2024;96:788-801.

Fighting Amyotrophic Lateral Sclerosis by Protecting the Liver? A Prospective Cohort Study.

BACKGROUND: Previous studies have observed liver abnormalities in amyotrophic lateral sclerosis (ALS) patients. This study aimed to investigate whether early signs of liver disease, measured by magnetic resonance imaging-derived iron-corrected T1-mapping (cT1), are risk factors for developing ALS. METHODS: cT1 and proton density fat fraction were measured and automatically analyzed using LiverMultiScan® software. The Fibrosis-4 index was calculated using an established formula based on age and blood markers. Cox proportional hazard models were used to examine the relationship between liver disease, liver biomarkers, and incident ALS. RESULTS: In a cohort of 533,707 individuals from UK Biobank, 24 ALS cases were identified among 28,328 participants with liver disease during the follow-up period. Among a total of 33,959 individuals with complete liver imaging data, 15 incident ALS cases were observed during a median follow-up period of 5.6 years. Individuals with liver disease had a higher risk of developing ALS, with an adjusted hazard ratio of 7.35 (95% CI 4.47-12.09; p < 0.001). An increase in cT1 was also associated with a higher risk of ALS. After adjusting for age, sex, Townsend deprivation index, smoking status, alcohol intake frequency, body mass index, proton density fat fraction, Fibrosis-4, and metabolic syndrome, an increase in cT1 remained significantly associated with a higher risk of ALS, with an adjusted hazard ratio of 3.15 (95% CI 1.79-5.55) per 1-SD increase. Sensitivity analyses confirmed these robust results. INTERPRETATION: Liver disease activity, indicated by cT1, increases the risk of developing ALS, independent of metabolic syndrome, liver fat, or fibrosis. ANN NEUROL 2024.

Metal-Stabilized Thiyl Radicals Design Inspired by Elemental Periodic Extension Notion for Ligand-Based Alkene Addition.

Inspired by alkene addition to the Ru and Re tris(thiolate) complexes via carbon-sulfur bond formation/cleavage reactions along with a periodic extension catalysis notion, a comparative study of the electronic structures, mechanisms, and reactivities for ethylene addition to the Os and Tc tris(thiolate) complexes was performed by DFT and high-level ab initio quantum calculations. The oxidized Os and Tc complexes were revealed to exhibit sufficient radical characters on the ligands to support their reaction with ethylene, whereas neutral Tc tris(thiolate) complex featuring little thiyl radical character renders no reactivity toward ethylene. Differential reactivities of these tris(thiolate) complexes was deemed to derive from the synergy of the thiyl radical character, the electronegativity, the row, and the charge. Extending from Ru and Re tris(thiolate) complexes to their Os and Tc counterparts can help us to get insightful rationales that would promote further research on alkene addition to metal-stabilized thiyl radicals.

Tea quality evaluation by applying E-nose combined with chemometrics methods.

Tea is one of the most popular beverage with distinct flavor consumed worldwide. It is of significance to establish evaluation method for tea quality controlling. In this work, electronic nose (E-nose) was applied to assess tea quality grades by detecting the volatile components of tea leaves and tea infusion samples. The "35th s value", "70th s value" and "average differential value" were extracted as features from E-nose responding signals. Three data reduction methods including principle component analysis (PCA), multi-dimensional scaling (MDS) and linear discriminant analysis (LDA) were introduced to improve the efficiency of E-nose analysis. Logistic regression (LR) and support vector machine (SVM) were applied to set up qualitative classification models. The results indicated that LDA outperformed original data, PCA and MDS in both LR and SVM models. SVM had an advantage over LR in developing classification models. The classification accuracy of SVM based on the data processed by LDA for tea infusion samples was 100%. Quantitative analysis was conducted to predict the contents of volatile compounds in tea samples based on E-nose signals. The prediction results of SVM based on the data processed by LDA for linalool (training set: R2 = 0.9523; testing set: R2 = 0.9343), nonanal (training set: R2 = 0.9617; testing set: R2 = 0.8980) and geraniol (training set: R2 = 0.9576; testing set: R2 = 0.9315) were satisfactory. The research manifested the feasibility of E-nose for qualitatively and quantitatively analyzing tea quality grades.

Ripeness Prediction of Postharvest Kiwifruit Using a MOS E-Nose Combined with Chemometrics.

Postharvest kiwifruit continues to ripen for a period until it reaches the optimal "eating ripe" stage. Without damaging the fruit, it is very difficult to identify the ripeness of postharvest kiwifruit by conventional means. In this study, an electronic nose (E-nose) with 10 metal oxide semiconductor (MOS) gas sensors was used to predict the ripeness of postharvest kiwifruit. Three different feature extraction methods (the max/min values, the difference values and the 70th s values) were employed to discriminate kiwifruit at different ripening times by linear discriminant analysis (LDA), and results showed that the 70th s values method had the best performance in discriminating kiwifruit at different ripening stages, obtaining a 100% original accuracy rate and a 99.4% cross-validation accuracy rate. Partial least squares regression (PLSR), support vector machine (SVM) and random forest (RF) were employed to build prediction models for overall ripeness, soluble solids content (SSC) and firmness. The regression results showed that the RF algorithm had the best performance in predicting the ripeness indexes of postharvest kiwifruit compared with PLSR and SVM, which illustrated that the E-nose data had high correlations with overall ripeness (training: R² = 0.9928; testing: R² = 0.9928), SSC (training: R² = 0.9749; testing: R² = 0.9143) and firmness (training: R² = 0.9814; testing: R² = 0.9290). This study demonstrated that E-nose could be a comprehensive approach to predict the ripeness of postharvest kiwifruit through aroma volatiles.

Exploring genetic association of systemic iron status and risk with incidence of diabetic neuropathy.

BACKGROUND: Diabetic neuropathy (DN), a frequent complication in individuals with diabetes mellitus (DM), is hypothesized to have a correlation with systemic iron status, though the nature of this relationship remains unclear. This study employs two-sample Mendelian randomization (MR) analysis to explore this potential genetic association. METHODS: We used genetic instruments significant associated with iron status including serum iron, ferritin, transferrin, and transferrin saturation, derived from an extensive Genome-Wide Association Study (GWAS) undertaken by the Genetics of Iron Status Consortium, involving a cohort of 48,972 European ancestry individuals. Summary statistics for DN were collected from a public GWAS, including 1,415 patients and 162,201 controls of European descent. Our MR analysis used the inverse-variance-weighted (IVW) method, supplemented by MR-Egger, weighted-median (WM) methods, Cochran's Q test, MR-Egger intercept analysis, MR-Pleiotropy Residual Sum and Outlier (MR-PRESSO) method, and leave-one-out analysis to ensure robustness and consistency of the findings. RESULTS: No genetic causal relationship was found between iron status markers and DN (all IVW p value > 0.05). Interestingly, a causative effect of DN on ferritin (IVW: OR = 0.943, 95% CI = 0.892-0.996, p = 0.035) and transferrin saturation (IVW: OR = 0.941, 95% CI = 0.888-0.998, p = 0.044) emerged. Sensitivity analyses confirmed the absence of significant heterogeneity and horizontal pleiotropy. CONCLUSION: While systemic iron status was not found to be causally related to DN, our findings suggest that DN may increase the risk of iron deficiency. These results provide further evidence supporting iron supplementation in patients with DN.

Colloidal lignin particle reinforces the stability of Pickering emulsions prepared with zein nanoparticle.

Zein nanoparticle (ZNP) is at the forefront of research on Pickering emulsions, valued for its self-assembling and surfactant-free nature. Nevertheless, its emulsion stability is undermined by inadequate amphiphilicity. Colloidal lignin particle (CLP), characterized by its antithetical charge and amphiphilic nature, appears the promising for augmenting the stability of ZNP-based emulsion. This study meticulously investigated the impact of CLP on the colloidal properties and emulsifying performance of ZNP. The results revealed that electrostatic interactions between ZNP and CLP significantly mitigated the charge of ZNP and improved its hydrophilic/lipophilic balance. Under optimized conditions (1.0 wt% particle concentration, pH 4.0, 50% oil content), CLP notably reduced droplet sizes (41-225 µm) and enhanced the stability of ZNP-based Pickering emulsion, particularly at ZNP/CLP ratios of 6:4 and 5:5. In nature, CLP improved the stability ZNP-based Pickering emulsions via increased interfacial adsorption, enhanced steric hindrance, and reinforced viscous structure.

RuCo/ZrO2 Tandem Catalysts with Photothermal Confinement Effect for Enhanced CO2 Methanation.

Photothermal CO2 methanation reaction represents a promising strategy for addressing CO2-related environmental issues. The presence of efficient tandem catalytic sites with a localized high-temperature is an effective pathway to enhance the performance of CO2 methanation. Here the bimetallic RuCo nanoparticles anchored on ZrO2 fiber cotton (RuCo/ZrO2) as a photothermal catalyst for CO2 methanation are prepared. A significant photothermal CO2 methanation performance with optimal CH4 selectivity (99%) and rate (169.93 mmol gcat -1 h-1) is achieved. The photothermal energy of the RuCo bimetallic nanoparticles, confined by the infrared insulation and low thermal conductivity of the ZrO2 fiber cotton (ZrO2 FC), provides a localized high-temperature. In situ spectroscopic experiments on RuCo/ZrO2, Ru/ZrO2, and Co/ZrO2 indicate that the construction of tandem catalytic sites, where the Co site favors CO2 conversion to CO while incorporating Ru enhances CO* adsorption for subsequent hydrogenation, results in a higher selectivity toward CH4. This work opens a new insight into designing tandem catalysts with a photothermal confinement effect in CO2 methanation reaction.

Magnetic FNS/MILs nanofibers for highly efficient removal of norfloxacin via adsorption and Fenton-like reaction.

Iron-containing MOFs have attracted extensive interest as promising Fenton-like catalysts. In this work, magnetic Fe3O4 nanofiber (FNS)/MOFs composites with stable structure, included FNS/MIL-88B, FNS/MIL-88A and FNS/MIL-100, were prepared via the in-situ solvothermal method. The surface of the obtained fibers was covered by a dense and continuous MOFs layer, which could effectively solve the agglomeration problem of MOFs powder and improved the catalytic performance. The adsorption and catalytic properties of FNS/MOFs composites were evaluated by removal of norfloxacin. FNS/MIL-88B showed the best performance with a maximum adsorption capacity up to 214.09 mg/g, and could degrade 99% of NRF in 60 min. Meanwhile, FNS/MIL-88B had a saturation magnetization of 20 emu/g, and could be rapidly separated by an applied magnetic field. The self-supported nanofibers allowed the adequate contact between MOFs and pollutants, and promoted the catalytic activity and high stability. We believe that this work provided a new idea for the design and preparation of Fenton-like catalysts especially MOFs composites.

Fine-Grain High-Performance Densified Oxide Fibers Produced by Open Ultrafast High-Temperature Sintering.

The considerable grain growth occurring during the long-term high-temperature sintering of polycrystalline oxide fibers negatively affects their mechanical properties, which highlights the need for alternative sintering methods. Herein, open ultrafast high-temperature sintering (OUHS) in air, characterized by rapid heating/cooling (>10000 K min-1) and a short high-temperature holding time (<10 s), is used to produce 3 mol% yttria-stabilized zirconia continuous fibers with coherent boundaries forming robust connections between fine grains. The tensile strength of these fibers (2.33 GPa on average, sintering temperature = 1673 K) notably exceeds that of their counterparts produced by traditional sintering (1.17 GPa). The effects of pores on fiber mechanical properties are analyzed using experimental and theoretical methods. For a versatility demonstration, OUHS is applied to several types of polycrystalline oxide fibers (HfO2, Al2O3, TiO2, Y2O3, and La2Zr2O7), considerably improving their mechanical properties and enabling crystalline phase control, which demonstrates the suitability of this procedure for the development of high-performance materials.

Dual-Phasic, Well-Aligned, and Strong Flexible Hydrophobic Ceramic Membranes for Efficient Thermal Insulation in Extreme Conditions.

The inherent brittleness and hydrophilicity of ceramics pose a great challenge to designing a reliable structure that can resist mechanical loads and moisture in extreme conditions with high temperature and high humidity. Here, we report a two-phase hydrophobic silica-zirconia composite ceramic nanofiber membrane (H-ZSNFM) with exceptional mechanical robustness and high-temperature hydrophobic resistance. For the dual-phasic nanofibers, the amorphous silica blocked the connection of zirconia nanocrystals, and the lattice distortion was observed due to Si in the ZrO2 lattice. H-ZSNFM has strong strength (5-8.4 MPa), high hydrophobic temperature resistance (450 °C), high porosity (89%), low density (40 mg/cm3), low thermal conductivity (30 mW/m·K), and excellent thermal radiation reflectivity (90%). By simulating the actual high-temperature and high-humidity environment, 10-mm-thick H-ZSNFMs can reduce the heat source from 1365 to 380 °C and maintain complete hydrophobicity even in a water vapor environment of 350 °C. This means that it has superior insulation and waterproof performance even in a high-temperature water environment. For firefighting clothing, H-ZSNFM displayed waterproof and insulation layers, which have excellent thermal protection performance and achieve incompatibility between water and fire, providing valuable time for fire rescue and a safety line of defense for emergency personnel. This design strategy with mechanical robust and hydrophobic temperature resistance applies to the development of many other types of high-performance thermal insulation materials and presents a competitive material system for thermal protection in extreme conditions.

Revealing Disparities in Porous Networks Between Yttria Aerogel Assemblies with Nanosheets and Nanoparticles and Their Ultrathermal Insulation and Optical Properties.

Recent advancements have introduced anisotropic structures, particularly 2D nanosheets, into aerogels, resulting in unique morphologies and exceptional properties that differ from those assembled by isotropic nanoparticles. However, exploration of the distinct porous networks and the resulting properties is limited. We focus on rare earth yttria (Y2O3) aerogels as a case in point and demonstrate the synthesis of aerogels with nanosheet and nanoparticle assemblies using elaborative sol-gel chemistry. With the aid of X-ray computed tomography, three-dimensional visualizations of the aerogels provide relative compressive views of the porous network, revealing that the Y2O3 aerogel assembled by nanosheets possesses a hierarchical pore structure characterized by uneven pore distribution, particularly the presence of macropores throughout; in contrast, these consist of nanoparticles exhibiting a relative uniform pore distribution. High-temperature examinations indicate that the nanosheet aerogels are much more stable with a specific surface area of 64 m2·g-1 after being exposed at 1300 °C; meanwhile, the aerogels present durable and efficient thermal insulation performances. The exceptional thermal properties are attributed to the synergistic effects of the nanosheets' crystalline nature and the hierarchical porous network. The nanosheet Y2O3 aerogel also exhibited superior luminescent emission characteristics, further enhancing its potential for various applications. Our findings provide further insights into optimization of the microstructures in nanoporous aerogels, particularly through the utilization of anisotropic nanosheets.

Macrophages in Glioblastoma Development and Therapy: A Double-Edged Sword.

Glioblastoma (GBM) is one of the leading lethal tumors, featuring aggressive malignancy and poor outcome to current standard temozolomide (TMZ) or radio-based therapy. Developing immunotherapies, especially immune checkpoint inhibitors, have improved patient outcomes in other solid tumors but remain fatigued in GBM patients. Emerging evidence has shown that GBM-associated macrophages (GAMs), comprising brain-resident microglia and bone marrow-derived macrophages, act critically in boosting tumor progression, altering drug resistance, and establishing an immunosuppressive environment. Based on its crucial role, evaluations of the safety and efficacy of GAM-targeted therapy are ongoing, with promising (pre)clinical evidence updated. In this review, we summarized updated literature related to GAM nature, the interplay between GAMs and GBM cells, and GAM-targeted therapeutic strategies.

Nanoporous Functionalized WS2/MWCNTs Nanocomposite for Trimethylamine Detection Based on Quartz Crystal Microbalance Gas Sensor.

We have developed a tungsten disulfide (WS2)/multiwall carbon nanotubes (MWCNTs) nanocomposite based QCM gas sensor for (trimethylamine) TMA gas sensing of low concentrations. WS2/MWCNTs nanocomposite was synthesized via the hydrothermal method and was characterized for surface morphology, nanostructure, thermal stability, and elementary composition. The TMA-sensing properties of WS2/MWCNTs nanocomposite based QCM sensor were investigated. The composite based QCM sensor showed faster response time, strong response amplitude, good gas capacity, and good selectivity and stability compared with as prepared WS2 and MWCNTs-1 based QCM sensor. The response time of WS2/MWCNTs based QCM sensor was 294.1 and 142.9 s shorter than WS2 and MWCNTs-1 for 500 ppb TMA gas. And the response of the WS2/MWCNTs based QCM sensor was almost stable over 40 days, and the limit of detection (LOD) was 76 ppb calculated by the ICH method. This was ascribed to the fact that MWCNTs provided a skeleton for the growth of WS2 nanosheets and avoided agglomeration. The special structure could not only improve the structure ability but also expose more active adsorption sites. In order to further investigate the adsorption mechanism of the TMA molecule on (pure/functionalized) WS2 materials, density functional theory (DFT) calculations based on first-principle were conducted in the Vienna Ab-initio Simulation Package under ideal conditions.

Phase Structure and Electrical Properties of Sm-Doped BiFe0.98Mn0.02O3 Thin Films.

Bi1-xSmxFe0.98Mn0.02O3 (x = 0, 0.02, 0.04, 0.06; named BSFMx) (BSFM) films were prepared by the sol-gel method on indium tin oxide (ITO)/glass substrate. The effects of different Sm content on the crystal structure, phase composition, oxygen vacancy content, ferroelectric property, dielectric property, leakage property, leakage mechanism, and aging property of the BSFM films were systematically analyzed. X-ray diffraction (XRD) and Raman spectral analyses revealed that the sample had both R3c and Pnma phases. Through additional XRD fitting of the films, the content of the two phases of the sample was analyzed in detail, and it was found that the Pnma phase in the BSFMx = 0 film had the lowest abundance. X-ray photoelectron spectroscopy (XPS) analysis showed that the BSFMx = 0.04 film had the lowest oxygen vacancy content, which was conducive to a decrease in leakage current density and an improvement in dielectric properties. The diffraction peak of (110) exhibited the maximum intensity when the doping amount was 4 mol%, and the minimum leakage current density and a large remanent polarization intensity were also observed at room temperature (2Pr = 91.859 µC/cm2). By doping Sm at an appropriate amount, the leakage property of the BSFM films was reduced, the dielectric property was improved, and the aging process was delayed. The performance changes in the BSFM films were further explained from different perspectives, such as phase composition and oxygen vacancy content.

Anisotropic morphology, formation mechanisms, and fluorescence properties of zirconia nanocrystals.

ZrO2 nanocrystals with spheres and elongated platelets were systemically prepared through a simple hydrothermal method by the use of ZrOCl2·8H2O and CH3COOK as raw materials. The anisotropic morphology and formation mechanism of the monoclinic and/or tetragonal ZrO2 were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscope, and high-resolution transmission electron microscope techniques. The uniform elongated platelets and star-like structures were composed of short nanorods with a diameter of approximately 5 nm and a length of approximately 10 nm. The different morphologies were formed due to the different contents of CH3COO- and Cl- and their synergy. The fluorescence band position and the band shape remained about the same for excitation wavelengths below 290 nm and the different morphologies of the nanocrystals.

Electrospun SiO2-MgO hybrid fibers for heavy metal removal: Characterization and adsorption study of Pb(II) and Cu(II).

SiO2-MgO hybrid fibers (SMHFs) were fabricated by one-step electrospinning process, characterized, and evaluated in heavy metal adsorption, for the first time. High-pressure steam (HPS) pretreated SMHFs showed high specific surface area (SBET) and large number of surface basic sites accompanied by the crystallization of MgO. The SMHFs showed high affinities for Pb(II) and Cu(II) with the distribution coefficients Kd>100 L·g-1 (when pH > 4). Langmuir model and pseudo-second-order kinetic model described the experimental data well, and the maximum adsorption capacities of 787.9 and 493.0 mg·g-1 for Pb(II) and Cu(II) at 298 K were the highest among those of reported SiO2-MgO adsorbents. Thermodynamics indicated SMHFs had the spontaneous and physicochemical adsorption nature. SMHFs kept good capacities in the presence of interfering substances and retained their reusability. The SMHFs with the superiority of high efficiency, low cost, easy preparation and environmentally benign, have promising applications in wastewater treatment and relative fields.

The qualitative and quantitative assessment of tea quality based on E-nose, E-tongue and E-eye combined with chemometrics.

Electronic nose (E-nose), electronic tongue (E-tongue) and electronic eye (E-eye) combined with chemometrics methods were applied for qualitative identification and quantitative prediction of tea quality. Main chemical components, such as amino acids, catechins, polyphenols and caffeine were measured by traditional methods. Feature-level fusion strategy for the integration of the signals was introduced to integrate the E-nose, E-tongue and E-eye signals, aiming at improving the performances of identification and prediction models. Perfect results with an accuracy of 100% were obtained for qualitative identification of tea quality grades, based on fusion signals by support vector machine and random forest. Quantitative models were established for predicting the contents of the chemical components based on independent electronic signals and fusion signals by partial least squares regression, support vector machine and random forest. Random forest based on the fusion signals achieved the best performance in predicting the concentration of those chemical components.

Application of the voltammetric electronic tongue based on nanocomposite modified electrodes for identifying rice wines of different geographical origins.

In the study, the voltammetric electronic tongue based on three nanocomposites modified electrodes was applied for the identification of rice wines of different geographical origins. The nanocomposites were prepared by gold and copper nanoparticles in the presence of conducting polymers (polymer sulfanilic acid, polymer glutamic acid) and carboxylic multi - walled carbon nanotubes. The modified electrodes showed high sensitivity to guanosine - 5' - monophosphate disodium salt, tyrosine and gallic acid which have good correlation with the geographical origins of rice wines. Scanning electron microscopy was performed to display the surface morphologies of the nanocomposites, and cyclic voltammetry was applied to study the electrochemical behaviors of the taste substances on the electrode surfaces. Four types of electrochemical parameters (pH, scan rates, accumulation potentials and time) were optimized for getting a low limit of the detection of each taste substance. The geographical information of rice wines was obtained by the modified electrodes based on two types of multi - frequency large amplitude pulse voltammetry, and "area method" was applied for extracting the feature data from the original information obtained. Based on the area feature data, principal component analysis, locality preserving projection (LPP), and linear discriminant analysis were applied for the classification of the rice wines of different geographical origins, and LPP presented the best results; extreme learning machine (ELM) and alibrary for support vector machines were applied for predicting the geographical origins of rice wines, and ELM performed better.

Tracing internal quality and aroma of a red-fleshed kiwifruit during ripening by means of GC-MS and E-nose.

'Hongyang' kiwifruit is a new breed of red-fleshed cultivar that has become broadly popular with consumers in recent years. In this study, the internal quality and aroma of this kiwifruit during ripening were investigated by means of gas chromatography-mass spectrometry (GC-MS) and electronic nose (E-nose). Results showed that the green note aldehydes declined, the main fruity esters increased, and the terpenes had no obvious changes during ripening. Correlations between quality indices, volatile compounds, and E-nose data were analyzed by ANOVA partial least squares regression (APLSR), and the results showed that firmness and titratable acidity (TA) had highly positive correlations with (E)-2-hexenal and hexanal, while soluble solids content (SSC) and SSC/TA ratio had positive correlations with ester compounds. The E-nose sensors of S7, S10, S8, S6, S9, and S2 were positively correlated with ester compounds, S1, S3, and S5 were mainly correlated with hexanal, and S4 was correlated with terpene compounds. Partial least squares regression (PLSR) and support vector machine (SVM) were employed to predict the quality indices by E-nose data, and SVM presented a better performance in predicting firmness, SSC, TA, and SSC/TA ratio (R 2 > 0.98 in the training set and R 2 > 0.94 in the testing set). This study demonstrated that the E-nose technique could be used as an alternative to trace the flavor quality of kiwifruit during ripening.