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A tandem blade configuration is a significant flow control method that delays the onset of flow separation. This study numerically investigates the effects of diffusion factor and percentage pitch on the flow structure of tandem blades. Diffusion factors vary from 0.328 to 0.484. Percentage pitches change from 0.80 to 0.92. Results show that the loss coefficient increases with diffusion factor and decreases with percentage pitch. There is a hub-corner stall of the forward blade in all cases. Gap flow determines the rear blade corner separation. Varying the percentage pitch and diffusion factor changes the momentum distribution of the gap flow. Corner separation of the rear blade is inhibited as low-momentum gap fluids are involved in the passage vortex along with the hub-corner stall of the forward blade. Increasing diffusion factor causes a change in incidence at the leading edge of the rear blade, resulting in a variation at the corner separation of the rear blade. A tandem blade is compared with the reference outlet vane. The performance of the tandem blade is superior to that of the reference outlet vane in all incidences, with a 26.35% reduction in the loss coefficient and a 7.89% enhancement in the pressurization at the designed incidence. Tandem blades stall at positive incidence because of the hub-corner stall of the forward blade. The intensity of the gap flow increases with incidence, preventing corner separation of the rear blade at positive incidences. [ABSTRACT FROM AUTHOR]

In this paper, we first introduce some types of set relations on the power set of n-dimensional Euclidean spaces which are proposed by Kuroiwa–Tanaka–Ha and Jahn–Ha. We also mention new types of cancellation laws of set relations. Second, we introduce a complete lattice-valued problem on the power set of n-dimensional Euclidean spaces proposed by Hamel et al. Applying nonlinear scalarizing technique in complete lattice, we present a new type of minimal element theorem and generalized Ekeland’s variational principles in complete lattice optimization problem. We also present an existence theorem of minimal solutions related to the famous Takahashi’s minimization theorem in complete lattice optimization problem. [ABSTRACT FROM AUTHOR]

Due to their high density, the ilmenite-bearing cumulates (IBC) (with or without KREEP) formed during the late-stage lunar magma ocean solidification are thought to sink into the underlying lunar mantle and trigger lunar mantle overturn. Geophysical evidence implied that IBC may descend deep inside the Moon and remain as a partially molten layer at the core-mantle boundary (CMB). However, partial melting may have occurred on the mixed mantle cumulates during the sinking of IBC/KREEP and the silicate melt may be positively buoyant, thus preventing the IBC/KREEP layer from sinking to the CMB. Here, we perform thermodynamic simulation on the stability of lunar mantle cumulates at different depths mixed with different amounts of IBC/KREEP from an updated LMO model. The modeling results suggest that the sinking of IBC/KREEP will cause at least 5 wt% partial melting in the shallow (~ 120 km) and a much larger degree of partial melting in the deep lunar mantle (~ 420 km). Due to the density contrast with the surrounding mantle, IBC/KREEP-bearing melts could potentially decouple under certain conditions. The modified lunar mantle by sinking of IBC/KREEP can better explain the formation of different kinds of lunar basaltic magma than the primary lunar mantle formed through differentiation of lunar magma ocean. Sinking of IBC/KREEP back into the lunar mantle may introduce plagioclase, clinopyroxene, garnet, and incompatible radioactive elements into the deep lunar mantle, which will further affect the thermal and chemical evolution of the lunar interior. [ABSTRACT FROM AUTHOR]

Focusing on promoting the widespread application of crystal self-healing technology in marine concrete engineering and improving the durability of marine concrete, the research on the chloride ion transport behavior and corrosion resistance of concrete with crystal admixtures under the action of seawater is conducted. Ion chelator (CA) as crystalline admixture can obviously improve self-healing of cement-based materials. Results showed that CA improved pore structure of mortar, increased the compactness of matrix, and thus limited the chloride diffusion. After 3 months of erosion by NaCl + Na2SO4, NaCl + MgCl2 and NaCl + MgCl2 + Na2SO4 solutions, compared with control sample, the chloride diffusion coefficient of 100%OPC mortar with CA decreased by 49.3%, 47.4%, 56.5%, and 52.9%, respectively. CA-enhanced chloride binding ability of 100%OPC and 50%BFS mortar. Compared with control sample, the chloride binding efficiency of 100%OPC mortar with CA and 50%BFS mortar with CA increased by 26.1% and 35.5% after 3 months of NaCl solution corrosion, increased by 35.3% and 48.0% after 3 months of NaCl + Na2SO4 solution corrosion, and increased by 46.2% and 61.9% after 3 months of NaCl + MgCl2 solution corrosion, respectively. SEM analysis showed that CA could significantly improve internal microstructure of mortar under salts erosion. The correlation analysis of pore structure and chloride diffusion coefficient displayed that total porosity of mortar had better correlation with chloride diffusion coefficient than gel pore, transition pore, capillary pore and macropore after salt erosion. Therefore, CA mainly limited chloride diffusion into matrix by reducing total porosity of mortar under salt erosion. The research results of this paper can provide theoretical support and basis for the application of crystal self-healing technology in marine concrete. [ABSTRACT FROM AUTHOR]

NiMZn/C@melamine sponge-derived carbon (MSDC) composites (M = Co, Fe, and Mn) were prepared by a vacuum pumping solution method followed by carbonization. A large number of carbon nanotubes (CNTs) homogeneously attached to the surfaces of the three-dimensional cross-linked of the sponge-derived carbon in the NiCoZn/C@MSDC composite, and CNTs were detected in the NiFeZn/C@MSDC and NiMnZn/C@MSDC composites. Ni3ZnC0.7, Ni3Fe, and MnO in-situ formed in the NiFeZn/C@MSDC and NiMnZn/C@MSDC composites. The CNTs in the NiCoZn/C@MSDC composite efficiently modulated its complex permittivity. Thus, the composite exhibited the best performance among the composites, with the minimum reflection loss (RLmin) of −33.1 dB at 18 GHz and thickness of 1.4 mm. The bandwidth for RL of ≤−10 dB was up to 5.04 GHz at the thickness of 1.7 mm and loading of 25wt%. The optimized impedance matching, enhanced interfacial and dipole polarization, remarkable conduction loss, and multiple reflections and scattering of the incident microwaves improved the microwave absorption performance. The effects of Co, Ni, and Fe on the phase and morphology provided an alternative way for developing highly efficient and broadband microwave absorbers. [ABSTRACT FROM AUTHOR]

This study investigates the influence of spinel crystallization characteristics on vanadium extraction during the converter vanadium slag-cooling process through thermodynamic calculations and experimental investigations. The phase evolution and micro-morphology variations of V-containing slag at different quenching temperatures are characterized via X-ray diffraction and scanning electron microscopy-energy dispersive X-ray spectroscopy, and the grain size of spinel phases is measured using an image processing software. Results indicate that the crystallization sequence in V-containing slag during the cooling process is V-spinel → Ti-spinel → olivine → rhodonite. When the temperature is reduced from 1400 °C to 1000 °C, the grain sizes of spinel exhibit a log-normal distribution, with the mean diameter and leaching rate of vanadium increasing from 15.11 to 27.27 μm and from 82.65 pct to 92.06 pct, respectively. The restrictive step in the crystallization process is the interfacial reaction. When cooled from 1000 °C to 25 °C, Ostwald ripening-type grain size distribution is observed, and the mean diameter increased to 41.9 μm. The vanadium leaching rate decreased to 85 pct due to the encapsulation of V-spinel by Ti-spinel and olivine, and the crystallization process is observed to be controlled by diffusion. [ABSTRACT FROM AUTHOR]

The present study investigated the microstructure and texture evolution of Mg-Sn alloy with and without pre-existing precipitates under different strain rates. Rod-shaped Mg2Sn phase was introduced in the Mg-Sn alloy by aging treatment. During deformation, the pre-existing Mg2Sn provided more nucleation sites for dynamic precipitation, which gave rise to a finer and higher fraction of the Mg2Sn phase. Additionally, strain rate significantly influenced the dynamic precipitation of Mg2Sn, with increasing Mg2Sn fraction as the strain rate decreased. Mg2Sn could effectively inhibit the dynamic recrystallization (DRX) process, resulting in a decreased dynamic recrystallization region with increasing Mg2Sn phase. The recrystallization texture intensity of the as-solutionized sample was weaker than that of the peak-aged sample, primarily because the low concentration of Sn atoms in the matrix was beneficial to the growth of DRX-ed grains with a similar orientation in the peak-aged sample and the fine and abundant precipitates hindered lattice deflection. [ABSTRACT FROM AUTHOR]

The max-min ant system (MMAS) algorithm has found extensive application in tackling combinatorial optimization challenges such as the traveling salesman problem (TSP), production scheduling, and quadratic assignment. Nevertheless, as the scale of the problem increases, the MMAS algorithm gradually encounters performance limitations. To address the performance constraints of MMAS, we propose a parallel max-min ant system (PMMAS) algorithm, where a master subpopulation coordinates multiple subpopulations in parallel search. Furthermore, to facilitate the parallel acceleration of computationally intensive tasks in PMMAS using the CPE array of the SW26010-Pro processor, the selection weight calculation equation in the traditional MMAS algorithm was improved. This improvement led to the introduction of the Sunway parallel max-min ant system (SWPMMAS) algorithm, which implements parallelism using MPI and Athread. The revised selection weight calculation equation is also applicable to the traditional MMAS algorithm and enhances its running speed. Finally, the SWPMMAS algorithm was evaluated using various TSP instances, with city counts ranging from 51 to 11,849. The results demonstrate that the SWPMMAS algorithm provides excellent solutions. For TSP instances with more than 10,000 cities, the SWPMMAS algorithm achieves over 13 × speedup compared to the PMMAS algorithm running on the Sunway architecture and 5.4 × speedup compared to the PMMAS algorithm running on a commercial Shanhe supercomputer. Moreover, testing indicates that the SWPMMAS algorithm exhibits outstanding scalability. [ABSTRACT FROM AUTHOR]

Selective oxidation of propane to acetone (AC) with H2 and O2 provides a direct route to convert low-cost propane into value-added products. Unfortunately, the catalytic activity of conventional Au/Ti-based catalysts is constrained by the high energy barrier for H2 dissociation. Herein, uncalcined TS-1 supported Au-Pd bimetallic catalysts were prepared, and the relationship between the active-site structure and corresponding performance in the selective oxidation of propane with H2 and O2 in the gas phase was systematically investigated. In contrast to the liquid-phase reaction, trace Pd alloyed with Au triggered an increase in both catalytic activity and selectivity, in which Au20-Pd1/TS-1-B catalyst exhibited excellent activity (170 gAC·h−1·kgcat−1) and AC selectivity (90.6%), much higher than those of the Au/TS-1-B catalyst (AC formation rate of 100 gAC·h−1·kgcat−1 and AC selectivity of 86.3%). It was found that Pd was gradually isolated into monomers with the increase of Au/Pd molar ratio, and the synergy between Pd single atoms and Au improved the catalytic performance via enhancing hydrogen dissociation and modulating the electronic structure of Au. Furthermore, the reaction conditions were optimized based on the kinetics studies and the Au20-Pd1/TS-1-B catalyst exhibited enhanced H2 selectivity (45%) and long-term stability (over 130 h). The insights gained here can offer valuable guidance for the design of Au-Pd catalysts applicable to other gas-phase oxidation reactions. [ABSTRACT FROM AUTHOR]

CoCrFeNiAlx (x = 0.3, 0.6, 0.9 and 1.2, molar ratio) high-entropy alloys (HEAs) were prepared by directional solidification at the withdrawal rate of 70 µm/s and were simply referred to as Al0.3, Al0.6, Al0.9 and Al1.2 alloy, respectively. The effects of Al content on microstructure evolution, component segregation and compressive property of these alloys were investigated. The study revealed that increasing Al content induced a transition from face-centered cubic (FCC) to body-centered cubic (BCC) crystal structure. Simultaneously, the microstructure transformed from coarse irregular dendrites to equiaxed dendrites and the morphology of the solid-liquid interface changed from cellular dendrites to dendrites. Specifically, the Al0.3 alloy exhibited the single FCC phase, while the Al0.6 alloy consisted of dendritic FCC of phase CoCrFe-enriched and inter-dendritic BCC phase of AlNi-enriched. The Al0.9 and Al1.2 alloys showed AlNi-enriched precipitate B2 phase and CoCrFe-enriched matrix FCC phase. As the Al content increased, the CoCrFeNiAlx HEAs ultimate compressive strength initially increased and then decreased. The Al0.9 alloy achieved the supreme ultimate compressive strength of 2265.17 MPa, attributed to crystal structure transformation and solid solution strengthening. Additionally, the compressive strain consistently decreased with increasing Al content, reaching the minimum of 23.46% for the Al1.2 alloy. [ABSTRACT FROM AUTHOR]

PM2.5 pollution variations in different microenvironments would result in PM2.5 exposure inequity between rural and urban residents. In this study, the real-time PM2.5 exposure of urban and rural residents in China was examined based on portable PM2.5 sensors together with activity patterns derived from questionnaire surveys, with a focus on students and senior citizens who are sensitive to air pollution. The results showed that PM2.5 exposure varied significantly among different resident groups, with higher PM2.5 exposure of rural residents than those of urban residents. PM2.5 exposure peaks mostly occurred during (Accompanied) cooking activities owing to strong emissions. Sleeping and resting were the main activities that affected PM2.5 exposures of different resident groups, accounting for 60.7%–94.5% of total daily exposures. Furthermore, the long duration of sleeping makes it the predominant activity contributing to PM2.5 exposure inequity. It is necessary to obtain point-to-point respiratory volume (respiratory rate) data when measuring real-time PM2.5 exposure data and incorporate respiratory volume (respiratory rate) into the analysis of PM2.5 exposure. For the first time, this study quantified the PM2.5 exposure inequality based on a novel method and can provide useful information for further studies on the exposure inequity. [ABSTRACT FROM AUTHOR]

A precisely designed dual-color biosensor has realized a visual assessment of thymidine kinase 1 (TK1) mRNA in both living cells and cell lysates. The oligonucleotide probe is constructed by hybridizing the antisense strand of the target and two recognition sequences, in which FAM serves as the donor and TAMRA as the acceptor. Once interacting with the target, two recognition strands are replaced, and then the antisense complementary sequence forms a more stable double-stranded structure. Due to the increasing spatial distance between two dyes, the FRET is attenuated, leading to a rapid recovery of FAM fluorescence and a reduction of TAMRA fluorescence. A discernible color response from orange to green could be observed by the naked eye, with a limit of detection (LOD) of 0.38 nM and 5.22 nM for spectrometer- and smartphone-based assays, respectively. The proposed ratiometric method transcends previous reports in its capacities in visualizing TK1 expression toward reliable nucleic acid biomarker analysis, which might establish a general strategy for ratiometric biosensing via strand displacement. [ABSTRACT FROM AUTHOR]

This paper efficiently addresses the high-dimensional robust order scheduling problem. A novel algorithm named dynamic cooperative coevolution based on an implicit decision variable classification approach (DCC/IDVCA) is developed to search for robust order schedules. To significantly reduce the computational resources required for solving the high-dimensional robust order scheduling problem, we propose decomposing the original decision variables through implicit classification methods. First, a novel estimation method is introduced to evaluate the weighted contribution of variables to robustness. This method utilizes historical information, including the variation of the overall mean effective fitness and the frequency of variables being classified into highly robustness-related subcomponents in previous cycles, for evaluating their weighted contribution to robustness. Then, based on the corresponding weighted robustness contributions, the original variables are classified into highly and weakly robustness-related variables. Finally, these two types of variables are decomposed into highly and weakly robustness-related subgroups within a dynamic cooperative coevolution framework and optimized separately. In the experimental section, the proposed algorithm is applied to two practical order scheduling problems in discrete manufacturing industry. The experimental results demonstrate that the proposed algorithm achieves competitive outcomes compared to state-of-the-art high-dimensional robust multi-objective optimization algorithms. [ABSTRACT FROM AUTHOR]

In this study, the mechanical properties and failure characteristics of bolted and hybrid bonded-bolted GFRP/Al joints under different loading speeds were investigated. The failure process and strain evolution were recorded using high-speed cameras and digital image correlation (DIC) techniques. The micro-morphology of the fracture was also investigated to explore the effect of loading speed on the fracture mode. The results showed that the peak load, failure displacement, and energy absorption for all joints were sensitive to the loading speed. The peak load and energy absorption of the hybrid joints were higher than that of the bolted joints under both static and dynamic loading. The loading speed had no significant effect on the failure mode of GFRP material in bolted joints, which were all shear-out failures. While for the hybrid joint, the addition of the adhesive layer changed the failure mode of GFRP material from shear-out failures to tension failures. As the loading speed increased, the final failure area of GFRP in hybrid joints gradually decreased. In hybrid joints, a greater amount of bearing damage preceded a final tension failure in GFRP material with the increase in loading speed. The fracture surface became flatter and the pulled-out fiber bundles were more integral due to the fact that cracks within the material could not extend sufficiently at high loading rates. [ABSTRACT FROM AUTHOR]

This cohort study was performed to explore the influence of intensive care unit (ICU) quality on in-hospital mortality of veno-venous (V-V) extracorporeal membrane oxygenation (ECMO)-supported patients in China. The study involved all V-V ECMO-supported patients in 318 of 1700 tertiary hospitals from 2017 to 2019, using data from the National Clinical Improvement System and China National Critical Care Quality Control Center. ICU quality was assessed by quality control indicators and capacity parameters. Among the 2563 V-V ECMO-supported patients in 318 hospitals, a significant correlation was found between ECMO-related complications and prognosis. The reintubation rate within 48 hours after extubation and the total ICU mortality rate were independent risk factors for higher in-hospital mortality of V-V ECMO-supported patients (cutoff: 1.5% and 7.0%; 95% confidence interval: 1.05–1.48 and 1.04–1.45; odds ratios: 1.25 and 1.23; P = 0.012 and P = 0.015, respectively). Meanwhile, the V-V ECMO center volume was a protective factor (cutoff of ≥ 50 cases within the 3-year study period; 95% confidence interval: 0.57–0.83, odds ratio: 0.69, P = 0.0001). The subgroup analysis of 864 patients in 11 high-volume centers further strengthened these findings. Thus, ICU quality may play an important role in improving the prognosis of V-V ECMO-supported patients. [ABSTRACT FROM AUTHOR]

Seepage erosion in the water-rich sandy strata, induced by the broken subsurface pipeline, has considerably complex interactions with the adjacent foundation pile. In order to investigate their interaction mechanism, six physical model tests considering different relative positions of pile are carried out in this study. By observing and measuring the variation of eroded form of soil layers, sand loss quantity and soil strength, the blocking effect and local intensification effect of foundation pile on seepage erosion are analyzed quantitatively and intuitively. And it's found that when the foundation pile is closer to the loss hole, the local intensification of erosion around pile is more significant, while the blocking effect of pile that extends the eroded area is relatively reduced. On the other hand, the earth pressure, bearing capacity, and unbalanced force and moment of pile are measured and calculated during the erosion, and their response characteristics to erosion are obtained that the pile bearing capacity quickly declines, the unbalanced force and moment on pile significantly increase with erosion, and the variation degree is more dramatical when the pile is closer to the loss hole. The research presented by this study is conducive to the safety control of urban underground space and the next-step numerical modeling on this issue. [ABSTRACT FROM AUTHOR]

In many real-life scenarios, multiple agents necessitate cooperation to accomplish tasks. Benefiting from the significant success of deep learning, many single-agent deep reinforcement learning algorithms have been extended to multi-agent scenarios. Overestimation in value estimation of Q-learning is a significant issue that has been studied comprehensively in the single-agent domains, but rarely in multi-agent reinforcement learning. In this paper, we first demonstrate that Q-learning-based multi-agent reinforcement learning (MARL) methods generally have notably serious overestimation issues, which cannot be alleviated by current methods. To tackle this problem, we introduce the double critic networks structure and the delayed policy update to Q-learning-based multi-agent MARL methods, which reduce the overestimation and enhance the quality of policy updating. To demonstrate the versatility of our proposed method, we select several Q-learning based MARL methods and evaluate them on several multi-agent tasks on the multi-agent particle environment and SMAC. Experimental results demonstrate that the proposed method can avoid the overestimation problem and significantly improve performance. Besides, application in the Traffic Signal Control verifies the feasibility of applying the proposed method in real-world scenarios. [ABSTRACT FROM AUTHOR]

Nowadays ε-caprolactone, the monomer of biodegradable polycaprolactone, is mainly produced via the strong exothermic Baeyer–Villiger oxidation of cyclohexanone in semi-batch reactors. In this work, the continuous synthesis of ε-caprolactone was conducted in a self-designed microreactor system to address its strong exothermic feature, resulting in a cyclohexanone conversion of 90.3% and an ε-caprolactone yield of 82.6%. Analysis using a liquid chromatography equipped with high resolution time-of-flight mass spectrometer suggested that the byproducts mainly consist of ε-caprolactone oligomers in the form of dimer, trimer, and tetramer. Such oligomers were produced via hydrolysis of ε-caprolactone, followed by esterification of the hydrolysis product, 6-hydroxyhexanoic acid. Kinetic studies suggest that the hydrolysis reaction orders for ε-caprolactone and water are 0.75 and 2.52, respectively, while dimerization of 6-hydroxyhexanoic acid is a zero-order reaction. The activation energies of the hydrolysis and dimerization were ~ 77.5 kJ·mol−1 and ~ 55.4 kJ·mol−1, respectively. Density functional theory calculations revealed the significant catalytic effect of acetic acid on both side reactions, where the dimerization of 6-hydroxyhexanoic acid proceeds through an alkoxy pathway. Highlights: • Continuous synthesis of ε-caprolactone was conducted in a microreactor to address its strong exothermic feature • Side reactions consist of hydrolysis of ε-caprolactone and oligomerization of 6-hydroxyhexanoic acid • Kinetic parameters were obtained and an alkoxy pathway was proposed for the dimerization of 6-hydroxyhexanoic acid [ABSTRACT FROM AUTHOR]

An extensive numerical investigation is conducted to characterize the flow separation control in a transonic compressor cascade with a porous bleed. The bleed holes are arranged on the suction surface in a single row, two staggered rows and three staggered rows. For each bleed scheme, five bleed pressure ratios are examined at an inlet Mach number of 1.0. The results indicate that the aerodynamic performance of the cascade is significantly improved by the porous bleed. For the single-row scheme, the maximum reduction in total pressure losses is 57%. For the two-staggered-row and three-staggered-row schemes, there is an optimal bleed pressure ratio of 1.0, and the maximum reductions in total pressure loss are 68% and 75%, respectively. The low loss in the cascade is due to the well-controlled boundary layer. The new local supersonic region created by the bleed hole is the key reason for the improved boundary layer. The vortex induced by side bleeding provides another mechanism for delaying flow separation. Increasing the bleed holes could create multiple local supersonic regions, which reduce the range of the adverse pressure gradient that the boundary layer needs to withstand. This is the reason why cascades with more bleed holes perform better. [ABSTRACT FROM AUTHOR]

The enhancement of horizontal boundaries of potential field sources is of great significance for the study of geological structures. Most of the existing filters for horizontal edges enhancement are presented based on the derivatives of potential field data, but these filters often show some shortcomings, for example, the output edges are divergent, strong and weak anomalies cannot be balanced, or some extra false edges appear in the results. In this paper, the edges enhancement filter MMA based on mathematical morphology is first defined by the combination of the basic operators of mathematical morphology. In order to make the filter have the ability to balance different amplitude anomalies, MMAZ and MMAT are proposed, and both of them can be used to delineate the horizontal edges of the field sources by their maxima. The experimental results of synthetic data show that MMAZ and MMAT have good equalization and anti-noise performances. Compared with several traditional filters, the horizontal edges of geological bodies obtained by these two filters are clearer and more convergent, and there are no extra edges in the output results for the complex situations that positive and negative anomalies exist simultaneously. Finally, the two new equalization filters are applied to gravity anomaly data in a potash mine area in Vientiane basin of Laos and the aeromagnetic anomaly of a metal mine in northwest China, the obtained positions of the structures are more accurate and clearer, which further illustrates the effectiveness of the two filtering techniques. [ABSTRACT FROM AUTHOR]

The study is about the size distribution and health risks of polycyclic aromatic hydrocarbons (PAHs) in indoor environment of Xuanwei, Southwest China particle samples were collected by Anderson 8-stage impactor which was used to gather particle samples to nine size ranges. Size-segregated samples were collected in indoor from a rural village in Xuanwei during the non-heating and heating seasons. The results showed that the total concentrations of the indoor particulate matter (PM) were 757 ± 60 and 990 ± 78 μg/m3 in non-heating and heating seasons, respectively. The total concentration of indoor PAHs reached to 8.42 ± 0.53 μg/m3 in the heating season, which was considerably greater than the concentration in the non-heating season (2.85 ± 1.72 μg/m3). The size distribution of PAHs showed that PAHs were mainly enriched in PMs with the diameter <1.1 μm. The diagnostic ratios (DR) and principal component analysis (PCA) showed that coal and wood for residential heating and cooking were the main sources of indoor PAHs. The results of the health risk showed that the total deposition concentration (DC) in the alveolar region (AR) was 0.25 and 0.68 μg/m3 in the non-heating and heating seasons respectively. Throughout the entire sampling periods, the lifetime cancer risk (R) based on DC of children and adults varied between 3.53 ×10−5 to 1.79 ×10−4. During the heating season, the potential cancer risk of PAHs in adults was significant, exceeding 10−4, with a rate of 96%. [ABSTRACT FROM AUTHOR]

Microstructural abnormalities of white matter fiber tracts are considered as one of the etiology of diabetes-induced neurological disorders. We explored the cerebral white matter microstructure alteration accurately, and to analyze its correlation between cerebral small vessel disease (CSVD) burden and cognitive performance in type 2 diabetes mellitus (T2DM). The clinical-laboratory data, cognitive scores [including mini-mental state examination (MMSE), Montreal cognitive assessment (MoCA), California verbal learning test (CVLT), and symbol digit modalities test (SDMT)], CSVD burden scores of the T2DM group (n = 34) and healthy control (HC) group (n = 21) were collected prospectively. Automatic fiber quantification (AFQ) was applied to generate bundle profiles along primary white matter fiber tracts. Diffusion tensor images (DTI) metrics and 100 nodes of white matter fiber tracts between groups were compared. Multiple regression analysis was used to analyze the relationship between DTI metrics and cognitive scores and CSVD burden scores. For fiber-wise and node-wise, DTI metrics in some commissural and association fibers were increased in T2DM. Some white matter fiber tracts DTI metrics were independent predictors of cognitive scores and CSVD burden scores. White matter fiber tracts damage in patients with T2DM may be characterized in specific location, especially commissural and association fibers. Aberrational specific white matter fiber tracts are associated with visuospatial function and CSVD burden. [ABSTRACT FROM AUTHOR]

Propylene epoxidation by H2 and O2 to propylene oxide (PO) over the Au-Ti bifunctional catalysts, as an ideal reaction for PO production, has attracted great interest. Revealing the mechanism of acrolein formation is of great importance for understanding the mechanism of molecular oxygen activation and the formation of hydroperoxo species on the Au sites. Here, we investigate the reaction mechanism of propylene oxidation to acrolein on the Au/uncalcined TS-1 (Au/TS-1-B) catalyst through a combination of multiple characterization, H2/D2 exchange, kinetics experiment, and modeling. The Ti sites are found to be non-essential to acrolein formation. Moreover, the acrolein formation on the Au/TS-1-B catalyst is confirmed to be promoted by H2 through hydroperoxo species formation, which includes two main steps: propylene dehydrogenation to *C3H5 with the aid of *OOH species, and *C3H5 oxidation by *OOH to acrolein. The latter step is determined to be the rate-determining step because the corresponding kinetics model gives the best description for experimental results. This work not only provides kinetics insights for the propylene hydro-oxidation to acrolein on the Au-Ti bifunctional catalysts, but also facilitates the rational design of Au catalysts with high activity and selectivity in the direct propylene epoxidation with H2 and O2. [ABSTRACT FROM AUTHOR]

Profiling users' temporal learning interests is key to online course recommendation. Previous studies mainly profile users' learning interests by aggregating their historical behaviors with simple fusing strategies, which fails to capture their temporal interest patterns underlying the sequential user behaviors. To fill the gap, we devise a recommender that incorporates time-aware Transformers and a knowledge graph to better capture users' temporal learning interests. First, we introduce stacked Transformers to extract users' temporal learning interests underlying users' course enrollment sequences. In addition, we design a time-aware positional encoding module to consider the enrollment time intervals between courses. Third, we incorporate a knowledge graph to utilize the latent knowledge connections between courses. The proposed method outperforms state-of-the-art baselines for course recommendation. Furthermore, findings in the ablation study offers several insights for future research. The proposed model can be implemented in online learning platforms to increase user engagement and reduce dropout rate. [ABSTRACT FROM AUTHOR]

Background: Colorectal cancer (CRC) is widely acknowledged as a prevalent malignancy and the second most common cause of cancer-related mortality worldwide. The aim of this study was to examine the independent impact of Median Household Income (MHI) on prognosis and survival outcomes in patients with CRC. Methods: Data from 17 cancer registries of the United States Surveillance, Epidemiology, and End Results program, with follow-up extended until November 2022 was analyzed. A Cox proportional hazards regression analysis was conducted to evaluate the influence of different levels of MHI on survival outcomes among patients with CRC. A total of 761,697 CRC patient records were retrieved from the SEER database. Results: The Cox regression analysis results indicated that patients with higher MHI exhibited improved overall survival outcomes when compared to those with lower MHI (MMHI: P < 0.001; HMHI: P < 0.001). Regardless of the specific tumor location, gender, stage of CRC, or treatment method, higher MHI is consistently linked to improved survival outcomes. However, this association was not found to be statistically significant among American Indian/Alaska Native (MMHI: P = 0.017; HMHI: P = 0.081), Asian or Pacific Islander (MMHI: P = 0.223; HMHI: P = 0.002) and unmarried or domestic partner patients (MMHI: P = 0.311; HMHI: P = 0.011). Conclusion: These results emphasize the importance of considering socioeconomic factors, such as income level, in understanding and addressing disparities in survival outcomes of CRC patients. [ABSTRACT FROM AUTHOR]

In geotechnical and tunneling engineering, accurately determining the mechanical properties of jointed rock holds great significance for project safety assessments. Peak shear strength (PSS), being the paramount mechanical property of joints, has been a focal point in the research field. There are limitations in the current peak shear strength (PSS) prediction models for jointed rock: (i) the models do not comprehensively consider various influencing factors, and a PSS prediction model covering seven factors has not been established, including the sampling interval of the joints, the surface roughness of the joints, the normal stress, the basic friction angle, the uniaxial tensile strength, the uniaxial compressive strength, and the joint size for coupled joints; (ii) the datasets used to train the models are relatively limited; and (iii) there is a controversy regarding whether compressive or tensile strength should be used as the strength term among the influencing factors. To overcome these limitations, we developed four machine learning models covering these seven influencing factors, three relying on Support Vector Regression (SVR) with different kernel functions (linear, polynomial, and Radial Basis Function (RBF)) and one using deep learning (DL). Based on these seven influencing factors, we compiled a dataset comprising the outcomes of 493 published direct shear tests for the training and validation of these four models. We compared the prediction performance of these four machine learning models with Tang's and Tatone's models. The prediction errors of Tang's and Tatone's models are 21.8% and 17.7%, respectively, while SVR_linear is at 16.6%, SVR_poly is at 14.0%, and SVR_RBF is at 12.1%. DL outperforms the two existing models with only an 8.5% error. Additionally, we performed shear tests on granite joints to validate the predictive capability of the DL-based model. With the DL approach, the results suggest that uniaxial tensile strength is recommended as the material strength term in the PSS model for more reliable outcomes. [ABSTRACT FROM AUTHOR]

Highlights: 3D cubic hollow core–shell NiCo2O4@C composites were synthesized. Oxygen vacancies were introduced into the prepared composites. Ultrabroad effective absorption bandwidth of 12.48 GHz was obtained. The absorption performance mechanism of NiCo2O4/C composites was investigated. Cobalt nickel bimetallic oxides (NiCo2O4) have received numerous attentions in terms of their controllable morphology, high temperature, corrosion resistance and strong electromagnetic wave (EMW) absorption capability. However, broadening the absorption bandwidth is still a huge challenge for NiCo2O4-based absorbers. Herein, the unique NiCo2O4@C core–shell microcubes with hollow structures were fabricated via a facile sacrificial template strategy. The concentration of oxygen vacancies and morphologies of the three-dimensional (3D) cubic hollow core–shell NiCo2O4@C framework were effectively optimized by adjusting the calcination temperature. The specially designed 3D framework structure facilitated the multiple reflections of incident electromagnetic waves and provided rich interfaces between multiple components, generating significant interfacial polarization losses. Dipole polarizations induced by oxygen vacancies could further enhance the attenuation ability for the incident EM waves. The optimized NiCo2O4@C hollow microcubes exhibit superior EMW absorption capability with minimum RL (RLmin) of −84.45 dB at 8.4 GHz for the thickness of 3.0 mm. Moreover, ultrabroad effective absorption bandwidth (EAB) as large as 12.48 GHz (5.52–18 GHz) is obtained. This work is believed to illuminate the path to synthesis of high-performance cobalt nickel bimetallic oxides for EMW absorbers with excellent EMW absorption capability, especially in broadening effective absorption bandwidth. [ABSTRACT FROM AUTHOR]

Objective: Nanoparticles (NPs) hold a great promise in combating rheumatoid arthritis, but are often compromised by their toxicities because the currently used NPs are usually synthesized by chemical methods. Our group has previously fabricated Ångstrom-scale silver particles (AgÅPs) and demonstrated the anti-tumor and anti-sepsis efficacy of fructose-coated AgÅPs (F-AgÅPs). This study aimed to uncover the efficacy and mechanisms of F-AgÅPs for arthritis therapy. Methods: We evaluated the efficacy of F-AgÅPs in collagen-induced arthritis (CIA) mice. We also compared the capacities of F-AgÅPs, the commercial AgNPs, and the clinical drug methotrexate (MTX) in protecting against K/BxN serum-transfer arthritis (STA) mice. Moreover, we evaluated the effects of F-AgÅPs and AgNPs on inflammation, osteoclast formation, synoviocytes migration, and matrix metalloproteinases (MMPs) production in vitro and in vivo. Meanwhile, the toxicities of F-AgÅPs and AgNPs in vitro and in vivo were also tested. Results: F-AgÅPs significantly prevented bone erosion, synovitis, and cartilage damage, attenuated rheumatic pain, and improved the impaired motor function in mouse models of CIA or STA, the anti-rheumatic effects of which were comparable or stronger than AgNPs and MTX. Further studies revealed that F-AgÅPs exhibited similar or greater inhibitory abilities than AgNPs to suppress inflammation, osteoclast formation, synoviocytes migration, and MMPs production. No obvious toxicities were observed in vitro and in vivo after F-AgÅPs treatment. Conclusions: F-AgÅPs can effectively alleviate arthritis without notable toxicities and their anti-arthritic effects are associated with the inhibition of inflammation, osteoclastogenesis, synoviocytes migration, and MMPs production. Our study suggests the prospect of F-AgÅPs as an efficient and low-toxicity agent for arthritis therapy. [ABSTRACT FROM AUTHOR]

Direct band gap GeSn alloys have recently emerged as promising lasing source materials for monolithic integration on Si substrate. In this work, optically pumped mid-infrared GeSn lasers were studied with the observation of dual-wavelength lasing at 2187 nm and 2460 nm. Two simultaneous lasing regions include a GeSn buffer layer (bulk) and a SiGeSn/GeSn multiple quantum well structure that were grown seamlessly using a chemical vapor deposition reactor. The onset of dual lasing occurs at 420 kW/cm2. The wider bandgap SiGeSn partitioning barrier enables the independent operation of two gain regions. While the better performance device in terms of lower threshold may be obtained by using two MQW regions design, the preliminary results and discussions in this work paves a way towards all-group-IV dual wavelength lasers monolithically integrated on Si substrate. [ABSTRACT FROM AUTHOR]

Excitons in monolayer semiconductors, benefitting from their large binding energies, hold great potential towards excitonic circuits bridging nano-electronics and photonics. However, achieving room-temperature ultrafast on-chip electrical modulation of excitonic distribution and flow in monolayer semiconductors is nontrivial. Here, utilizing lateral bias, we report high-speed electrical modulation of the excitonic distribution in a monolayer semiconductor junction at room temperature. The alternating charge trapping/detrapping at the two monolayer/electrode interfaces induces a non-uniform carrier distribution, leading to controlled in-plane spatial variations of excitonic populations, and mimicking a bias-driven excitonic flow. This modulation increases with the bias amplitude and eventually saturates, relating to the energetic distribution of trap density of states. The switching time of the modulation is down to 5 ns, enabling high-speed excitonic devices. Our findings reveal the trap-assisted exciton engineering in monolayer semiconductors and offer great opportunities for future two-dimensional excitonic devices and circuits. 2D excitonic devices hold potential for on-chip optoelectronic applications. Here, the authors report high-speed in-plane electrical modulations of the excitonic distribution in monolayer semiconductor/Au electrode junctions, showing switching times as low as 5 ns at room temperature. [ABSTRACT FROM AUTHOR]

The increase in temperature caused by global climate change has promoted the salinization of wetlands. Inland saline-alkaline wetlands have an environment of over-humidity and shallow water and are hot spots for CH4 emissions. However, there are few reports on the effect of salinity on CH4 emissions in inland saline-alkaline wetlands. This study conducted simulation experiments of increased salinity to investigate the impact of salinity, habitat, and their interactions on CH4 emissions, as well as to examine the response of methanogenic archaea to salinity. Overall, salinity inhibited CH4 emissions. But there were different responses in the three habitat soils. Salinity decreased the relative abundance of methanogenic archaea and changed the community structure. In addition, salinity changed soil pH and dissolved organic carbon (DOC) and ammonium (NH4+) concentrations, which were significantly correlated with methanogenic archaea. Our study showed that salinity changed the soil physicochemical properties and characteristics of the methanogenic archaeal community, affecting CH4 emissions. [ABSTRACT FROM AUTHOR]

The divergent reductive cross-coupling with an ambident electrophile is rare. Previously, we demonstrated a nickel-catalyzed reductive 2-pyridination of aryl iodides with difluoromethyl 2-pyridyl sulfone (2-PySO2CF2H) via selective C(sp2)–S bond cleavage of the sulfone by using a phosphine ligand. In this communication, we report a novel nickel-catalyzed reductive coupling of aryl iodides and 2-PySO2CF2H reagent, which constitutes a new method for aromatic difluoromethylation. The use of a tridentate terpyridine ligand is pivotal for the selective C(sp3)–S bond cleavage of the sulfone. This method employs readily available nickel catalyst and 2-PySO2CF2H as the difluoromethylation reagent, providing a facile access to difluoromethylarenes under mild reaction conditions without pre-generation of arylmetal reagents. [ABSTRACT FROM AUTHOR]

Droplet microfluidics is a rapidly advancing area of microfluidic technology, which offers numerous advantages for cell analysis, such as isolation and accumulation of signals, by confining cells within droplets. However, controlling cell numbers in droplets is challenging due to the uncertainty of random encapsulation which result in many empty droplets. Therefore, more precise control techniques are needed to achieve efficient encapsulation of cells within droplets. Here, an innovative microfluidic droplet manipulation platform had been developed, which employed positive pressure as a stable and controllable driving force for manipulating fluid within chips. The air cylinder, electro-pneumatics proportional valve, and the microfluidic chip were connected through a capillary, which enabled the formation of a fluid wall by creating a difference in hydrodynamic resistance between two fluid streams at the channel junction. Lowering the pressure of the driving oil phase eliminates hydrodynamic resistance and breaks the fluid wall. Regulating the duration of the fluid wall breakage controls the volume of the introduced fluid. Several important droplet microfluidic manipulations were demonstrated on this microfluidic platform, such as sorting of cells/droplets, sorting of droplets co-encapsulated cells and hydrogels, and active generation of droplets encapsulated with cells in a responsive manner. The simple, on-demand microfluidic platform was featured with high stability, good controllability, and compatibility with other droplet microfluidic technologies. [ABSTRACT FROM AUTHOR]

The temperature and equivalent strain distribution of SUS436L slabs were analyzed by a finite element (FE) model in the hot rolling processes considering different surface temperatures of the intermediate slab for finish rolling (IST). The practical rolling processes were operated and different ISTs were designed. With IST decreased, the deformation permeability and the deformation uniformity of the hot-rolled strips are improved due to the increased temperature difference between the surface and the center of the strips. After annealing at 980 °C for 180 s, the strips are dominated by substructure, followed by recrystallized grains. The fraction of the recrystallized grains, the grain homogeneity and the maximum of γ texture orientation density of the hot-rolled and annealed strips are increased with the IST decreased, and the average grain size decreased. As a result, the yield strength (RP0.2), the tensile strength (Rm), the percentage elongation after fracture (A) and the product of strength and elongation (U) of the hot-rolled and annealed strips are all increased with IST decreased and are 285, 441 MPa, 45.2% and 19.9 GPa·%, respectively, at 800 °C of IST. [ABSTRACT FROM AUTHOR]

Programmed cell death ligand 1 (PD-L1) expression remains the most widely used biomarker for predicting response to immune checkpoint inhibitors (ICI), but its predictiveness varies considerably. Identification of factors accounting for the varying PD-L1 performance is urgently needed. Here, using data from three independent trials comprising 1239 patients, we have identified subsets of cancer with distinct PD-L1 predictiveness based on tumor transcriptome. In the Predictiveness-High (PH) group, PD-L1+ tumors show better overall survival, progression-free survival, and objective response rate with ICI than PD-L1- tumors across three trials. However, the Predictiveness-Low (PL) group demonstrates an opposite trend towards better outcomes for PD-L1- tumors. PD-L1+ tumors from the PH group demonstrate the superiority of ICI over chemotherapy, whereas PD-L1+ tumors from the PL group show comparable efficacy between two treatments or exhibit an opposite trend favoring chemotherapy. This observation of context-dependent predictiveness remains strong regardless of immune subtype (Immune-Enriched or Non-Immune), PD-L1 regulation mechanism (adaptative or constitutive), tumor mutation burden, or neoantigen load. This work illuminates avenues for optimizing the use of PD-L1 expression in clinical decision-making and trial design, although this exploratory concept should be further confirmed in large trials. [ABSTRACT FROM AUTHOR]

This paper investigated the role of long-period stacking-order (LPSO) structure on the corrosion behavior of an Mg-Gd-Y-Zn-Zr alloy. The amounts of the LPSO phase were tailored by heat treatment. The as-received sample contained a small amount of lamellar LPSO phase and Mg5(Gd, Y) particles. The lamellar LPSO was dissolved into the Mg matrix by solution treatment and precipitated at a low cooling rate. Consequently, the sample cooled in a furnace contained large amounts of LPSO phase (furnace-cooled sample). However, almost no LPSO was detected in the sample when cooled into water (water-cooled sample). Corrosion tests indicated that the LPSO phase deteriorated the corrosion properties of Mg alloy. Surface morphology for samples after immersion in 3.5 wt.% NaCl solution implied that galvanic corrosion was predominant for the Mg-Gd-Y-Zn-Zr alloy. The LPSO phase with a low potential was preferentially corroded compared with the Mg matrix, and therefore, a poor corrosion resistance of the Mg alloy containing the LPSO phase. [ABSTRACT FROM AUTHOR]

This study aimed to explore key quality control factors that affected the prognosis of intensive care unit (ICU) patients in Chinese mainland over six years (2015–2020). The data for this study were from 31 provincial and municipal hospitals (3425 hospital ICUs) and included 2 110 685 ICU patients, for a total of 27 607 376 ICU hospitalization days. We found that 15 initially established quality control indicators were good predictors of patient prognosis, including percentage of ICU patients out of all inpatients (%), percentage of ICU bed occupancy of total inpatient bed occupancy (%), percentage of all ICU inpatients with an APACHE II score ⩾15 (%), three-hour (surviving sepsis campaign) SSC bundle compliance (%), six-hour SSC bundle compliance (%), rate of microbe detection before antibiotics (%), percentage of drug deep venous thrombosis (DVT) prophylaxis (%), percentage of unplanned endotracheal extubations (%), percentage of patients reintubated within 48 hours (%), unplanned transfers to the ICU (%), 48-h ICU readmission rate (%), ventilator associated pneumonia (VAP) (per 1000 ventilator days), catheter related blood stream infection (CRBSI) (per 1000 catheter days), catheter-associated urinary tract infections (CAUTI) (per 1000 catheter days), in-hospital mortality (%). When exploratory factor analysis was applied, the 15 indicators were divided into 6 core elements that varied in weight regarding quality evaluation: nosocomial infection management (21.35%), compliance with the Surviving Sepsis Campaign guidelines (17.97%), ICU resources (17.46%), airway management (15.53%), prevention of deep-vein thrombosis (14.07%), and severity of patient condition (13.61%). Based on the different weights of the core elements associated with the 15 indicators, we developed an integrated quality scoring system defined as F score=21.35%xnosocomial infection management + 17.97%xcompliance with SSC guidelines + 17.46%×ICU resources + 15.53%×airway management + 14.07%×DVT prevention + 13.61%×severity of patient condition. This evidence-based quality scoring system will help in assessing the key elements of quality management and establish a foundation for further optimization of the quality control indicator system. [ABSTRACT FROM AUTHOR]

Summary: Mortality risk declined over time. Patients with fragility hip fracture experienced an approximate ninefold excess mortality, peaking shortly after fracture, in comparison with that of the general population. Continuous efforts in lowering the occurrence of hip fracture have the potential to improve the survival of the elderly population in China. Purpose: Hip fractures in older adults often lead to an elevated risk of death. However, few studies investigated mortality risk following hip fracture in mainland China. This retrospective cohort study aimed to evaluate the crude mortality and excess mortality after fragility hip fractures in Lishui residents aged 50 years and older. Methods: Patients having a fragility hip fracture between October 2013 and August 2019 were identified from the Lishui District Inpatient Data Collection and followed up until August 2020. Death information was ascertained from the linked death registry records. We calculated the follow-up mortality rate and corresponding 95% confidence intervals (CIs) as well as the standard mortality ratios (SMRs) in comparison with the mortality rates of Lishui residents. Results: During the study period, a total of 808 patients (63.4% females) with an average age of 75 years were admitted for fragility hip fractures. The 1st, 2nd, and 3rd year follow-up mortality rates were 16.51, 6.06, and 5.03 per 100 person-year, respectively. The SMRs were 8.46 (6.94, 9.97), 5.74 (4.86, 6.63), and 4.63 (3.98, 5.27) for the 1st, 2nd, and 3rd year following fragility hip fracture. Conclusion: Although mortality risk declined over time, patients with fragility hip fracture experienced an approximate ninefold excess mortality, peaking shortly after fracture, in comparison with that of the general population. Continuous efforts in lowering the occurrence of hip fracture have the potential to improve the survival of the elderly population in China. [ABSTRACT FROM AUTHOR]

The reversible transformation of a nanohelix is one of the most exquisite and important phenomena in nature. However, nanomaterials usually fail to twist into helical crystals. Considering the irreversibility of the previously studied twisting forces, the reverse process (untwisting) is more difficult to achieve, let alone the retwisting of the untwisted crystalline nanohelices. Herein, we report a new reciprocal effect between molecular geometry and crystal structure which triggers a twisting-untwisting-retwisting cycle for tri-cobalt salicylate hydroxide hexahydrate. The twisting force stems from competition between the condensation reaction and stacking process, different from the previously reported twisting mechanisms. The resulting distinct nanohelices give rise to unusual structure elasticity, as reflected in the reversible change of crystal lattice parameters and the mutual transformation between the nanowires and nanohelices. This study proposes a fresh concept for designing reversible processes and brings a new perspective in crystallography. The reversible transformation of a nanohelix is one of the most exquisite and important phenomenon in nature but nanomaterials usually fail to twist into helical crystals or untwist. Here, the authors report a reciprocal effect between molecular geometry and crystal structure which triggers a twisting-untwisting-retwisting cycle for tri-cobalt salicylate hydroxide hexahydrate. [ABSTRACT FROM AUTHOR]

Nanoscale zero-valent iron (nZVI) has received more attention due to its high reactivity in removing contaminants. However, assessing reactivity requires time and cost savings to improve the potential applicability of nZVI. In this study, a model for Cr(VI) removal by nZVI was established to simulate the changes of various ions during the reaction. The aim was to elucidate the reduction mechanism and provide a new method for calculating electron efficiency. And we calibrated the parameters through experimental data and characterization analysis, which improved the reliability of the model. In addition, we discussed the specific effects of the initial concentration and initial pH of Cr(VI) on electron efficiency and reactivity. The results indicated that the initial concentration and initial pH primarily affected the electron efficiency by altering the utilization efficiency of active sites and the corrosion degree of nZVI. At pH values of 3, 5, 7, 9, and 11, the electron efficiencies were 39.18%, 47.56%, 58.81%, 59.12%, and 84.19%, respectively. We found that both nZVI and Fe(II) had reduction effects, but which one played the major role depended on the reaction conditions. Finally, the possible reaction mechanisms were analyzed by combining experiments, models, and characterizations. The whole reaction process was divided into three stages: pollutant adsorption, electron transfer process, and mass transfer process. [ABSTRACT FROM AUTHOR]

Purpose: To explore the clinical and radiological effects of the free vascularized iliac bone flap (FVIBF) based on deep iliac circumflex vessels for Association Research Circulation Osseous (ARCO) stage 3 traumatic osteonecrosis of the femoral head (TONFH) in young adults. Methods: From February 2017 to August 2020, a total of 29 (29 hips) TONFH patients with ARCO stage 3 were enrolled in this study. Following the FVIBF standard procedure, the necrotic area of the femoral head was removed and a free vascularized iliac bone flap was harvested and grafted. X-rays were performed at 1, 3, 6, 9, and 12 months and every 6 months thereafter postoperatively for evaluation of the degree of femoral head collapse. The Beijing University of Chinese Medicine X-ray Evaluation Method (BUCMXE) was used to evaluate the hip preservation effects based on anteroposterior hip radiographs. Hip functions were evaluated using the Harris hip score (HHS) every 6 months and annually after 24 months, and the quality of life was assessed using the SF-36 questionnaire at 18 months postoperatively. Results: The mean follow-up time was 30 months (range 12–54 months). None of the patients was lost to follow-up, and the wounds healed primarily without infection and deep venous thrombosis of lower limbs. The HHS at 12 months postoperatively was significantly improved than that before surgery (83.4 ± 7.4 vs. 64.8 ± 14.1; p < 0.05). The BUCMXE radiographic score at 12 months postoperatively did not reveal any significant differences in femoral head morphology and osteonecrotic lesion, when compared to preoperation. The SF-36 questionnaire showed significant improvements in social functioning, role physical, bodily pain, and general health (p < 0.05). However, eight patients had varying degrees of femoral head collapse after surgery, and only one of them underwent THA due to pain and collapse aggravation. BUCMXE-Osteoarthritis scores showed that 23 hips were stable and six hips were advanced, among which five hips staged ARCO 3B and one staged ARCO 3A preoperatively, with statistically significant differences (p < 0.05). Conclusion: Although some patients showed no improvement of radiological outcomes, most patients with severe TONFH could still benefit from the FVIBF procedure. Further studies should attempt to improve this surgical procedure and explore its long-term efficacy. [ABSTRACT FROM AUTHOR]

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