The advancement of aqueous magnesium ion energy storage devices encounters limitations due to the substantial hydration radius of magnesium ions(Mg^(2+))and their strong electrostatic interaction with the primary mate...The advancement of aqueous magnesium ion energy storage devices encounters limitations due to the substantial hydration radius of magnesium ions(Mg^(2+))and their strong electrostatic interaction with the primary material.Consequently,this study successfully developed a MnS/MnO heterostructure through a straightforward hydrothermal and annealing method,marking its initial application in aqueous magnesium ion capacitors(AMICs).The fabricated MnS/MnO heterostructure,characterized by S defects,also generates Mn defects via in-situ initiation of early electrochemical processes.This unique dual ion defects MnS/MnO heterostructure(DID-MnS/MnO)enables the transformation of MnS and MnO,initially not highly active electrochemically for Mg^(2+),into cathode materials exhibiting high electrochemical activity and superior performance.Moreover,DID-MnS/MnO enhances conductivity,improves the kinetics of surface redox reactions,and increases the diffusion rate of Mg^(2+).Furthermore,this study introduces a dual energy storage mechanism for DID-MnS/MnO,which,in conjunction with dual ion defects,offers additional active sites for Mg^(2+)insertion/deinsertion in the host material,mitigating volume expansion and structural degradation during repeated charge-discharge cycles,thereby significantly enhancing cycling reversibility.As anticipated,using a three-electrode system,the developed DID-MnS/MnO demonstrated a discharge specific capacity of 237.9 mAh/g at a current density of 0.1 A/g.Remarkably,the constructed AMIC maintained a capacity retention rate of 94.3%after 10000 cycles at a current density of 1.0 A/g,with a specific capacitance of 165.7 F/g.Hence,DID-MnS/MnO offers insightful perspectives for designing alternative clean energy sources and is expected to contribute significantly to the advancement of the clean energy sector.展开更多
Osteogenesis imperfecta(OI)is a group of diseases caused by defects in type I collagen processing which result in skeletal fragility.While these disorders have been regarded as defects in osteoblast function,the role ...Osteogenesis imperfecta(OI)is a group of diseases caused by defects in type I collagen processing which result in skeletal fragility.While these disorders have been regarded as defects in osteoblast function,the role of matrix-embedded osteocytes in OI pathogenesis remains largely unknown.Homozygous human SP7(c.946 C>T,R316C)mutation results in a recessive form of OI characterized by fragility fractures,low bone mineral density and osteocyte dendrite defects.To better understand how the OI-causing R316C mutation affects the function of SP7,we generated Sp7^(R342C)knock-in mice.Consistent with patient phenotypes,Sp7^(R342C/R342C)mice demonstrate increased cortical porosity and reduced cortical bone mineral density.Sp7^(R342C/R342C)mice show osteocyte dendrite defects,increased osteocyte apoptosis,and intracortical bone remodeling with ectopic intracortical osteoclasts and elevated osteocyte Tnfsf11 expression.展开更多
To solve the problem of low detection accuracy for complex weld defects,the paper proposes a weld defects detection method based on improved YOLOv5s.To enhance the ability to focus on key information in feature maps,t...To solve the problem of low detection accuracy for complex weld defects,the paper proposes a weld defects detection method based on improved YOLOv5s.To enhance the ability to focus on key information in feature maps,the scSE attention mechanism is intro-duced into the backbone network of YOLOv5s.A Fusion-Block module and additional layers are added to the neck network of YOLOv5s to improve the effect of feature fusion,which is to meet the needs of complex object detection.To reduce the computation-al complexity of the model,the C3Ghost module is used to replace the CSP2_1 module in the neck network of YOLOv5s.The scSE-ASFF module is constructed and inserted between the neck network and the prediction end,which is to realize the fusion of features between the different layers.To address the issue of imbalanced sample quality in the dataset and improve the regression speed and accuracy of the loss function,the CIoU loss function in the YOLOv5s model is replaced with the Focal-EIoU loss function.Finally,ex-periments are conducted based on the collected weld defect dataset to verify the feasibility of the improved YOLOv5s for weld defects detection.The experimental results show that the precision and mAP of the improved YOLOv5s in detecting complex weld defects are as high as 83.4%and 76.1%,respectively,which are 2.5%and 7.6%higher than the traditional YOLOv5s model.The proposed weld defects detection method based on the improved YOLOv5s in this paper can effectively solve the problem of low weld defects detection accuracy.展开更多
The accuracy and reliability of non-destructive testing(NDT)approaches in detecting interior corrosion problems are critical,yet research in this field is limited.This work describes a novel way to monitor the structu...The accuracy and reliability of non-destructive testing(NDT)approaches in detecting interior corrosion problems are critical,yet research in this field is limited.This work describes a novel way to monitor the structural integrity of steel gas pipelines that uses advanced numerical modeling techniques to anticipate fracture development and corrosion effects.The objective is to increase pipeline dependability and safety through more precise,real-time health evaluations.Compared to previous approaches,our solution provides higher accuracy in fault detection and quantification,making it ideal for pipeline integritymonitoring in real-world applications.To solve this issue,statistical analysis was conducted on the size and directional distribution features of about 380,000 sets of internal corrosion faults,as well as simulations of erosion and wear patterns on bent pipes.Using real defectmorphologies,we developed a modeling framework for typical interior corrosion flaws.We evaluated and validated the applicability and effectiveness of in-service inspection processes,as well as conducted on-site comparison tests.The results show that(1)the length and width of corrosion defects follow a log-normal distribution,the clock orientation follows a normal distribution,and the peak depth follows a Freundlich EX function distribution pattern;(2)pipeline corrosion defect data can be classified into three classes using the K-means clustering algorithm,allowing rapid and convenient acquisition of typical size and orientation characteristics of internal corrosion defects;(3)the applicability range and boundary conditions of various NDT techniques were verified,establishing comprehensive selection principles for internal corrosion defect detection technology;(4)on-site inspection results showed a 31%The simulation and validation platform for typical interior corrosion issues greatly enhances the accuracy and reliability of detection data.展开更多
The rapid progress in the construction of heavy-haul and high-speed railways has led to a surge in rail defects and unforeseen failures.Addressing this issue necessitates the implementation of more sophisticated rail ...The rapid progress in the construction of heavy-haul and high-speed railways has led to a surge in rail defects and unforeseen failures.Addressing this issue necessitates the implementation of more sophisticated rail inspection methods,specifically involving real-time,precise detection,and assessment of rail defects.Current applications fail to address the evolving requirements,prompting the need for advancements.This paper provides a summary of various types of rail defects and outlines both traditional and innovative non-destructive inspection techniques,examining their fundamental features,benefits,drawbacks,and practical suitability for railway track inspection.It also explores potential enhancements to equipment and software.The comprehensive review draws upon pertinent international research and review papers.Furthermore,the paper introduces a fusion of inspection methods aimed at enhancing the overall reliability of defect detection.展开更多
Infectious bone defects represent a substantial challenge in clinical practice,necessitating the deployment of advanced therapeutic strategies.This study presents a treatment modality that merges a mild photothermal t...Infectious bone defects represent a substantial challenge in clinical practice,necessitating the deployment of advanced therapeutic strategies.This study presents a treatment modality that merges a mild photothermal therapy hydrogel with a pulsed drug delivery mechanism.The system is predicated on a hydrogel matrix that is thermally responsive,characteristic of bone defect sites,facilitating controlled and site-specific drug release.The cornerstone of this system is the incorporation of mild photothermal nanoparticles,which are activated within the temperature range of 40–43°C,thereby enhancing the precision and efficacy of drug delivery.Our findings demonstrate that the photothermal response significantly augments the localized delivery of therapeutic agents,mitigating systemic side effects and bolstering efficacy at the defect site.The synchronized pulsed release,cooperated with mild photothermal therapy,effectively addresses infection control,and promotes bone regeneration.This approach signifies a considerable advancement in the management of infectious bone defects,offering an effective and patient-centric alternative to traditional methods.Our research endeavors to extend its applicability to a wider spectrum of tissue regeneration scenarios,underscoring its transformative potential in the realm of regenerative medicine.展开更多
Mechano luminescence(ML),which involves the emission of light under mechanical stimuli,shows great potential in various applications such as sensing,imaging,and energy harvesting.Current research suggests that the lum...Mechano luminescence(ML),which involves the emission of light under mechanical stimuli,shows great potential in various applications such as sensing,imaging,and energy harvesting.Current research suggests that the luminescence mechanism of ML is typically connected to specific defects present within the material.In this study,we focus on the investigation of ML defects in Pr^(3+)-doped NaNbO_(3)/LiNbO_(3)heterojunctions,employing a combination of experimental and theoretical approaches.Through experimental analysis,we confirmed the presence of the heterojunction and its influence on ML intensity,and the optimal doping ratio for the heterojunction in ML was established.Furthermore,we examined the influence of varying Pr^(3+)doping concentrations on ML behavior and a proof-of-concept was demonstrated using the X-rays charged heterostructural phosphor as a stress sensor for biological applications.The position and concentration of internal defects in the ML material were scrutinized through thermo luminescence tests employing the variable heating rate method and positron annihilation.Complementing the experimental findings,theoretical simulations were conducted to elucidate the underlying mechanisms responsible for the observed ML defects.Density functional theory calculations were employed to investigate the energy levels,charge transfer processes,and lattice distortions within the heterojunctions under mechanical stress.Theoretical predictions were compared and validated against the experimental results.The integration of experimental and theoretical approaches provides a comprehensive understanding of the ML behavior of Pr^(3+)-doped NaNbO_(3)/LiNbO_(3)heterojunctions.The insights gained from this research contribute to the development of novel ML materials and pave the way for their applications in next-generation sensing and energy conversion devices.展开更多
The features of optical defects in a chemical vapor deposition (CVD) synthetic type Ⅱ a diamond were characterized using photoluminescence (PL) spectroscopy, before and after electron irradiation. The sample was cut ...The features of optical defects in a chemical vapor deposition (CVD) synthetic type Ⅱ a diamond were characterized using photoluminescence (PL) spectroscopy, before and after electron irradiation. The sample was cut within a {100} growth layer, and irradiated with 2 MeV electrons along the <100> axis. PL spectra of sample were collected under 532 nm and 355 nm laser excitation, at room temperature and 77 K, and linear scanning analysis along incident depth was applied to determine the distribution of defects. The pre-irradiation characterization results revealed uniformly distributed PL centers at 389 nm, 469 nm, 533 nm, 575 nm (ZPL of NV 0), 637 nm (ZPL of NV -), and 736.7/737.1 nm (ZPL doublet of SiV -). After irradiation, the differential responses of these as-grown defects were observed, alongside the emergence of irradiation-induced defects, namely 489 nm center, H3 center (ZPL at 504 nm) and GR1 center (ZPL at 741 nm). The maximum penetration depth of 2 MeV electron-irradiation induced defects was determined to be 2.1 mm. This work primarily presents the depth profiles of both as-grown and irradiation-induced defects in 2 MeV electrons irradiated diamond. The result provides experimental data for better understanding of the radiation effect in diamonds. Serving as a reference for diamond enhancement by electron irradiation.展开更多
Solution-processed Cu(In,Ga)Se_(2)(CIGS) solar cells suffer from serious carrier recombination and power conversion efficiency(PCE) loss because of the poor film properties and easy formation of defects.Herein, we pro...Solution-processed Cu(In,Ga)Se_(2)(CIGS) solar cells suffer from serious carrier recombination and power conversion efficiency(PCE) loss because of the poor film properties and easy formation of defects.Herein, we propose Ag&Se co-selenization strategy to enhance the crystallization and passivate harmful defects of the CIGS films. The formation of Ag-Se phase during the selenization process enables the formation of large grains and suppresses the deep level defects. It is found that Ag doping can enlarge the depletion region width, lower the Urbach energy and prolong the carrier lifetime. As a result, a champion solution-processed CIGS solar cell presents a high efficiency of 16.48% with the highly improved opencircuit voltage(VOC) of 662 m V and fill factor(FF) of 75.8%. This work provides an efficient strategy to prepare high quality solution-processed CIGS films for high-performance CIGS solar cells.展开更多
While early transition metal-based materials,such as MXene,has emerged as an efficient catalyst for the Mg-based hydrogen storage materials,their strong interaction with hydrogen resulted in the high hydrogen diffusio...While early transition metal-based materials,such as MXene,has emerged as an efficient catalyst for the Mg-based hydrogen storage materials,their strong interaction with hydrogen resulted in the high hydrogen diffusion barrier,hindering further improvement of catalytic activity.A MXene is characterized by rich anionic groups on its surface,significantly affecting electronic and catalytic functionalities.Using Nb_(2)CT_(x)as an example,we herein illustrate the critical role of anionic T_(x)defects on controlling hydrogen dissociation and diffusion processes in Mg-based hydrogen storage materials.The hydrogen desorption properties of MgH_(2)can be significantly enhanced by utilizing T_(x)controllable Nb_(2)CT_(x),and it can release 3.57 wt.%hydrogen within 10 min under 240℃with the reduced dehydrogenation activation barrier.It also realized stable de/hydrogenation reactions for at least 50 cycles.DFT studies combined with kinetic analysis revealed that the catalyst‒hydrogen interaction could be systematically controlled by optimizing surface T_(x)defect density,accelerating the hydrogen dissociation and diffusion processes at the same time.These results demonstrate that the T_(x)defects serve as the effective catalytically active centers of Nb_(2)CT_(x),offering a flexible catalyst design guideline.展开更多
Defects at the grain boundaries(GBs)of perovskite film highly restrict both the efficiency and stability of perovskite solar cells(PSCs).Herein,organic small molecules of butanedioic acid(BA)and acetylenedicarboxylic ...Defects at the grain boundaries(GBs)of perovskite film highly restrict both the efficiency and stability of perovskite solar cells(PSCs).Herein,organic small molecules of butanedioic acid(BA)and acetylenedicarboxylic acid(AA),containing two carbonyl(C=O)groups and different core-units,were incorporated into perovskite as additives for PSCs application.Thanks to the strong coordination interaction between C=O group and under-coordinated Pb^(2+),the additives can effectively passivate film defects and regulate the perovskite crystallization,yielding high-quality perovskite films with lower defect densities.More importantly,the additives can efficiently regulate the charge transport behaviors in PSCs.Benefiting from the defects passivation and the regulation of charge carrier dynamics,the BA and AA-treaded PSCs show the power conversion efficiencies of 21.52%and 20.50%,which are higher than that of the control device(19.41%).Besides,the optimal devices exhibit a remarkable enhanced long-term stability and moisture tolerance compared to the pristine devices.Furthermore,the transient absorption spectrum reveals the mechanism of enhanced photovoltaic performances,attributing to the improvement of charge transport capability at the perovskite/Spiro-OMeTAD interfaces.This work affords a promising strategy to improve the efficiency and stability of PSCs through regulating the charge-carrier dynamic process in perovskite film.展开更多
Following publication of the original article[1],the authors found that they pasted the same data when drawing XRD for sample NCO-1 and NCO-2 in Fig.2a,however,the XRD of all four samples in the manuscript was tested,...Following publication of the original article[1],the authors found that they pasted the same data when drawing XRD for sample NCO-1 and NCO-2 in Fig.2a,however,the XRD of all four samples in the manuscript was tested,and XRD raw data were kept and can be offered.The correct Fig.2 has been provided in this Correction.展开更多
Defect engineering is a commonly methodology used to enhance the thermoelectric performance of thermoelectric PbTe by improving its electronic transport properties.At the nanoscale,defects can induce quantum tunneling...Defect engineering is a commonly methodology used to enhance the thermoelectric performance of thermoelectric PbTe by improving its electronic transport properties.At the nanoscale,defects can induce quantum tunneling effects that significantly impact the electrical properties of materials.To understand the specific mechanisms underlying the quantum transport properties of PbTe,we employ the non-equilibrium Green's function(NEGF)method to investigate the effects of intrinsic defects(point defects and grain boundaries)on the electronic transport properties of PbTe-based nanodevices from a quantum mechanical perspective.Our results show that the Pb vacancy(VPb)has the highest conduction.The conduction depends on the defect type,chemical potential and bias voltage.The presence of intrinsic point defects introduces impurity levels,facilitating the electron tunneling and leading to an increase in the transmission coefficient,thereby enhancing the electronic transport properties.For PbTe containing grain boundaries,these boundaries suppress the electronic transport properties.The Te occupied twin boundary(Te-TB)exerts a stronger inhibitory effect than the Pb occupied twin boundary(Pb-TB).Nevertheless,the combined effect between twin boundaries and point defects can enhance the electrical properties.Therefore,in order to obtain highly conductive of PbTe materials,a Te-rich synthesis environment should be used to promote the effective formation of Pb vacancy.Our work offers a comprehensive understanding of the impact of defects on electron scattering in thermoelectric materials.展开更多
Failure tests were conducted on two concrete-filled steel tubular(CFST)truss arch bridges with a span of approximately 12 m to investigate the influence of initial geometric defects on the in-plane bearing capacity of...Failure tests were conducted on two concrete-filled steel tubular(CFST)truss arch bridges with a span of approximately 12 m to investigate the influence of initial geometric defects on the in-plane bearing capacity of CFST truss arch bridges.The effects of antisymmetric defect on the ultimate bearing capacity,failure mode,structural response,and steel–concrete confinement effect of CFST truss arch bridges under quarter-point loading were analyzed.On this basis,numerical simulations were conducted to investigate the in-plane bearing capacity of CFST truss arch bridges further under different scenarios.The initial defect formof the archwas obtained by using theoretical deduction,and the theoretical basis for the weakening of the ultimate bearing capacity of the arch bridge caused by geometric defects was clarified.Results indicate that the antisymmetric defect does not change the four-hinge failure mode of the model arch under quarter-point loading but increases the local cracking area and crack density of the concrete inside the pipe.The sine geometric defect with an amplitude of L/250 resulted in a 44.4%decrease in the yield load of the single hinge of the model arch,a 10.5%decrease in the failure load of the four hinges,and a 40.9%increase in themaximum vertical deformation during failure.At the initial stage of loading,the steel pipe and the concrete inside the pipe were subjected to relatively independent forces.After reaching 67%of the ultimate load,the catenary arch ribs began to produce a steel pipe concrete constraint effect.The initial geometric defects resulted in a decrease in the load when the constraint effect occurred.The antisymmetric defects with the same amplitude have a greater impact on the in-plane bearing capacity of the CFST arch bridge than the initial geometric defects with symmetry.The linear deviation at L/4 caused by constructionmust be controlled to be less than L/600 to ensure that the internal bearing capacity of the CFST arch bridge reaches 95%of the design bearing capacity.The structural deformation caused by geometric initial defects increases linearly with the increase in defect amplitude.The bearing capacity is weakened because the structural deflection and bending moment are amplified by initial defects.展开更多
Despite the extensive use of distributed fiber optic sensing(DFOS)in monitoring underground structures,its potential in detecting structural anomalies,such as cracks and cavities,is still not fully understood.To contr...Despite the extensive use of distributed fiber optic sensing(DFOS)in monitoring underground structures,its potential in detecting structural anomalies,such as cracks and cavities,is still not fully understood.To contribute to the identification of defects in underground structures,this study conducted a four-point bending test of a reinforced concrete(RC)beam and uniaxial loading tests of an RC specimen with local cavities.The experimental results revealed the disparity in DFOS strain spike profiles between these two structural anomalies.The effectiveness of DFOS in the quantification of crack opening displacement(COD)was also demonstrated,even in cases where perfect bonding was not achievable between the cable and structures.In addition,DFOS strain spikes observed in two diaphragm wall panels of a twin circular shaft were also reported.The most probable cause of those spikes was identified as the mechanical behavior associated with local concrete contamination.With the utilization of the strain profiles obtained from laboratory tests and field monitoring,three types of multi-classifiers,based on support vector machine(SVM),random forest(RF),and backpropagation neural network(BP),were employed to classify strain profiles,including crack-induced spikes,non-crack-induced spikes,and non-spike strain profiles.Among these classifiers,the SVM-based classifier exhibited superior performance in terms of accuracy and model robustness.This finding suggests that the SVM-based classifier holds promise as a potential solution for the automatic detection and classification of defects in underground structures during long-term monitoring.展开更多
Objective Exposure to polycyclic aromatic hydrocarbons(PAHs)or metal(loid)s individually has been associated with neural tube defects(NTDs).However,the impacts of PAH and metal(loid)co-exposure and potential interacti...Objective Exposure to polycyclic aromatic hydrocarbons(PAHs)or metal(loid)s individually has been associated with neural tube defects(NTDs).However,the impacts of PAH and metal(loid)co-exposure and potential interaction effects on NTD risk remain unclear.We conducted a case-control study in China among population with a high prevalence of NTDs to investigate the combined effects of PAH and metal(loid)exposures on the risk of NTD.Methods Cases included 80 women who gave birth to offspring with NTDs,whereas controls were 50 women who delivered infants with no congenital malformations.We analyzed the levels of placental PAHs using gas chromatography and mass spectrometry,PAH-DNA adducts with 32P-post-labeling method,and metal(loid)s with an inductively coupled plasma mass spectrometer.Unconditional logistic regression was employed to estimate the associations between individual exposures and NTDs.Least absolute shrinkage and selection operator(LASSO)penalized regression models were used to select a subset of exposures,while additive interaction models were used to identify interaction effects.Results In the single-exposure models,we found that eight PAHs,PAH-DNA adducts,and 28 metal(loid)s were associated with NTDs.Pyrene,selenium,molybdenum,cadmium,uranium,and rubidium were selected through LASSO regression and were statistically associated with NTDs in the multiple-exposure models.Women with high levels of pyrene and molybdenum or pyrene and selenium exhibited significantly increased risk of having offspring with NTDs,indicating that these combinations may have synergistic effects on the risk of NTDs.Conclusion Our findings suggest that individual PAHs and metal(loid)s,as well as their interactions,may be associated with the risk of NTDs,which warrants further investigation.展开更多
Intermetallic alloys offer exceptional high-temperature mechanical properties and low densities,thus rendering them suitable for a wide range of applications in aviation and spacecraft.However,their inherent brittlene...Intermetallic alloys offer exceptional high-temperature mechanical properties and low densities,thus rendering them suitable for a wide range of applications in aviation and spacecraft.However,their inherent brittleness at room temperature poses challenges in the manufacture of complex geometries.Hence,Laser additive manufacturing(LAM)has emerged as a promising approach to investigate the potential limitations of these materials.This review discusses the key findings and challenges associated with the LAM of intermetallic alloys,particu-larly NiAl,Ni_(3)Al,and TiAl,whose engineering applications are substantial.It provides an overview of typical defect morphologies,formation mechanisms,and strategies to prevent cracks and pores.Additionally,it presents an analysis of the microstructural characteristics of as-built and post-treated samples compared with those of samples prepared conventionally.Furthermore,the mechanical properties of the above-mentioned alloys at both room and high temperatures are reviewed,thus highlighting the effects of post-treatment processes.This review concludes with summary tables detailing the mechanical properties,which serve as useful references for researchers.展开更多
The regeneration of infected bone defects is still challenging and time-consuming,due to the adverse osteogenic microenvironment caused by bacterial contamination and pronounced ischemia.Biodegradable magnesium(Mg)-ba...The regeneration of infected bone defects is still challenging and time-consuming,due to the adverse osteogenic microenvironment caused by bacterial contamination and pronounced ischemia.Biodegradable magnesium(Mg)-based alloys are desirable for orthopedic implants due to the mechanical properties approximating those of human bone and the released Mg^(2+)ions essential to osteogenic activity.However,the fast and uncontrolled self-degradation of Mg alloy,along with the inadequate antimicrobial activity,limit their strength in the osteogenic microenvironment.Inspired by the structural and physiological characteristics of“fish scales,”two-dimensional(2D)nanomaterials,black phosphorus(BP)and graphene oxide(GO),were assembled together under the action of pulsed electric field.The bionic 2D layered BP/GO nano-coating was constructed for infection resistance,osteogenic microenvironment optimization,and biodegradation control.In the early stage of implantation,it exerted a photothermal effect to ablate bacterial biofilms and avoid contaminating the microenvironment.The blocking effect of the“nano fish scales”-2D material superposition regulated the degradation of implants.In the later stage,it attracted the migration of vascular endothelial cells(VECs)and released phosphate slowly for in situ mineralization to create the microenvironment favoring vascularized bone formation.It is indicated that the enhancement of microtubule deacetylation and cytoskeletal reorganization played a key role in the effect of VEC migration and angiogenesis.This study provided a promising bionic strategy for creating osteogenic microenvironments that match the sequential healing process of infected bone defects.展开更多
With the rapid development of heavy haul railway transportation technology,tunnel foundation defects and their effects on structural performance have attracted wide attention.This paper systematically investigates the...With the rapid development of heavy haul railway transportation technology,tunnel foundation defects and their effects on structural performance have attracted wide attention.This paper systematically investigates the evolution mechanism of tun-nel foundation defects in heavy haul railway tunnels and their impact on structural stiffness degradation through experiments and numerical simulations.A heavy haul train-ballasted track-tunnel basement-surround rock dynamic interaction model(TTTR model)is constructed.Firstly,the study reveals the four-stage evolution process of initial defects in the tunnel base-ment under complex environmental conditions.Experiments were conducted to measure the load-bearing capacity and stiff-ness degradation of the tunnel basement structure under different defect states.It is found that foundation defects,especially under the coupling of loose fill in the basement with the water-rich environment of the surrounding rock,significantly reduce the stiffness of the tunnel bottom structure and increase the risk of structural damage.Then,based on refined simulation of wheel-rail interaction and multi-scale coupled modeling technology,the TTTR dynamic interaction model was successfully constructed,and its validity was proven through numerical validation.A time-varying coupling technique of constrained boundary substructures(CBS technique)was adopted,significantly improving computational efficiency while ensuring calculation accuracy.The study also analyzes the effects of different degrees of void defects on the dynamic behavior of the train and the dynamic characteristics of the tunnel structure.It finds that foundation defects have a significant impact on the train’s operational state,track vibration displacement,and vibration stress of the tunnel lining structure,especially under the coupling effect of basement voids and the water-rich environment,which has the greatest impact.The research results of this paper provide a theoretical basis and technical support for the maintenance and reinforcement of tunnel foundation structures.展开更多
BACKGROUND The generation of intrabony defects due to the iatrogenic use of elastic bands is an undesirable situation that can result in persistent gingival inflammation with subsequent bone degradation,thus ultimatel...BACKGROUND The generation of intrabony defects due to the iatrogenic use of elastic bands is an undesirable situation that can result in persistent gingival inflammation with subsequent bone degradation,thus ultimately leading to tooth loss.CASE SUMMARY This clinical case involved a 27-year-old male patient who complained of persistent inflammation and bleeding in the upper anterior region of the gums,despite having undergone dental cleaning for at least 4 years.The dental and medical history indicated the use of removable orthodontic appliances for 8 years,after which braces were placed for 2 years.The intraoral evaluation revealed inflammation and localized suppuration in teeth 11 and 12.Measurements of 2-7 mm for probing depth and 1-5 mm for clinical attachment loss were detected,and combined bone loss was observed via radiographs.Based on the clinical and radiographic findings,localized stage III,grade C periodontitis was diagnosed.During subgingival debridement,two elastic bands emerged around the involved teeth.The bone defects persisted;therefore,they were surgically addressed using a papilla preservation flap and guided tissue regeneration(GTR).CONCLUSION The use of elastic bands of various sizes and elasticities is often essential in multiple orthodontic treatments.However,it is crucial to perform a thorough check-up for each patient during treatment and at the end of treatment to remove any remaining residue of resin,metal bands,or orthodontic bands.Additionally,it is imperative to inform the patients of the importance of attending their follow-up appointments.The use of elastic bands in orthodontics requires special care;moreover,GTR is a management option for intrabony defects associated with the iatrogenic use of bands.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52071171,52202248)Liaoning BaiQianWan Talents Program(LNBQW2018B0048)+8 种基金Shenyang Science and Technology Project(21-108-9-04)Key Research Project of Department of Education of Liaoning Province(LJKZZ20220015)the Research Fund for the Doctoral Program of Liaoning Province(2022-BS-114)Chunhui Program of the Ministry of Education of the People’s Republic of China(202201135)Australian Research Council(ARC)through Future Fellowship(FT210100298,FT210100806)Discovery Project(DP220100603)Linkage Project(LP210100467,LP210200504,LP210200345,LP220100088)Industrial Transformation Training Centre(IC180100005)schemes,and the Australian Government through the Cooperative Research Centres Projects(CRCPXIII000077)the Australian Renewable Energy Agency(ARENA)as part of ARENA’s Transformative Research Accelerating Commercialisation Program(TM021).
文摘The advancement of aqueous magnesium ion energy storage devices encounters limitations due to the substantial hydration radius of magnesium ions(Mg^(2+))and their strong electrostatic interaction with the primary material.Consequently,this study successfully developed a MnS/MnO heterostructure through a straightforward hydrothermal and annealing method,marking its initial application in aqueous magnesium ion capacitors(AMICs).The fabricated MnS/MnO heterostructure,characterized by S defects,also generates Mn defects via in-situ initiation of early electrochemical processes.This unique dual ion defects MnS/MnO heterostructure(DID-MnS/MnO)enables the transformation of MnS and MnO,initially not highly active electrochemically for Mg^(2+),into cathode materials exhibiting high electrochemical activity and superior performance.Moreover,DID-MnS/MnO enhances conductivity,improves the kinetics of surface redox reactions,and increases the diffusion rate of Mg^(2+).Furthermore,this study introduces a dual energy storage mechanism for DID-MnS/MnO,which,in conjunction with dual ion defects,offers additional active sites for Mg^(2+)insertion/deinsertion in the host material,mitigating volume expansion and structural degradation during repeated charge-discharge cycles,thereby significantly enhancing cycling reversibility.As anticipated,using a three-electrode system,the developed DID-MnS/MnO demonstrated a discharge specific capacity of 237.9 mAh/g at a current density of 0.1 A/g.Remarkably,the constructed AMIC maintained a capacity retention rate of 94.3%after 10000 cycles at a current density of 1.0 A/g,with a specific capacitance of 165.7 F/g.Hence,DID-MnS/MnO offers insightful perspectives for designing alternative clean energy sources and is expected to contribute significantly to the advancement of the clean energy sector.
基金support from the National Institute of Health(K99AR081897,R00AR081897)M.N.W.acknowledges funding support from the National Institute of Health(P01DK011794,R01DK116716)+1 种基金the Smith Family Foundation Odyssey Award,and the Chen Institute Massachusetts General Hospital Research Scholar(2024-2029)awardμCT and bone histomorphometry were performed by the Center for Skeletal Research at Massachusetts General Hospital,a NIH-funded program(P30AR066261 and AR075042)led by Mary Bouxsein and Marie Demay).
文摘Osteogenesis imperfecta(OI)is a group of diseases caused by defects in type I collagen processing which result in skeletal fragility.While these disorders have been regarded as defects in osteoblast function,the role of matrix-embedded osteocytes in OI pathogenesis remains largely unknown.Homozygous human SP7(c.946 C>T,R316C)mutation results in a recessive form of OI characterized by fragility fractures,low bone mineral density and osteocyte dendrite defects.To better understand how the OI-causing R316C mutation affects the function of SP7,we generated Sp7^(R342C)knock-in mice.Consistent with patient phenotypes,Sp7^(R342C/R342C)mice demonstrate increased cortical porosity and reduced cortical bone mineral density.Sp7^(R342C/R342C)mice show osteocyte dendrite defects,increased osteocyte apoptosis,and intracortical bone remodeling with ectopic intracortical osteoclasts and elevated osteocyte Tnfsf11 expression.
基金supported by Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX24_4084).
文摘To solve the problem of low detection accuracy for complex weld defects,the paper proposes a weld defects detection method based on improved YOLOv5s.To enhance the ability to focus on key information in feature maps,the scSE attention mechanism is intro-duced into the backbone network of YOLOv5s.A Fusion-Block module and additional layers are added to the neck network of YOLOv5s to improve the effect of feature fusion,which is to meet the needs of complex object detection.To reduce the computation-al complexity of the model,the C3Ghost module is used to replace the CSP2_1 module in the neck network of YOLOv5s.The scSE-ASFF module is constructed and inserted between the neck network and the prediction end,which is to realize the fusion of features between the different layers.To address the issue of imbalanced sample quality in the dataset and improve the regression speed and accuracy of the loss function,the CIoU loss function in the YOLOv5s model is replaced with the Focal-EIoU loss function.Finally,ex-periments are conducted based on the collected weld defect dataset to verify the feasibility of the improved YOLOv5s for weld defects detection.The experimental results show that the precision and mAP of the improved YOLOv5s in detecting complex weld defects are as high as 83.4%and 76.1%,respectively,which are 2.5%and 7.6%higher than the traditional YOLOv5s model.The proposed weld defects detection method based on the improved YOLOv5s in this paper can effectively solve the problem of low weld defects detection accuracy.
基金The“13th Five-Year Plan”National Science and Technology Major Project,2016ZX05052,Changchao QiThe China National Petroleum Corporation Science and Technology Project,2021DJ6505,Changchao Qi.
文摘The accuracy and reliability of non-destructive testing(NDT)approaches in detecting interior corrosion problems are critical,yet research in this field is limited.This work describes a novel way to monitor the structural integrity of steel gas pipelines that uses advanced numerical modeling techniques to anticipate fracture development and corrosion effects.The objective is to increase pipeline dependability and safety through more precise,real-time health evaluations.Compared to previous approaches,our solution provides higher accuracy in fault detection and quantification,making it ideal for pipeline integritymonitoring in real-world applications.To solve this issue,statistical analysis was conducted on the size and directional distribution features of about 380,000 sets of internal corrosion faults,as well as simulations of erosion and wear patterns on bent pipes.Using real defectmorphologies,we developed a modeling framework for typical interior corrosion flaws.We evaluated and validated the applicability and effectiveness of in-service inspection processes,as well as conducted on-site comparison tests.The results show that(1)the length and width of corrosion defects follow a log-normal distribution,the clock orientation follows a normal distribution,and the peak depth follows a Freundlich EX function distribution pattern;(2)pipeline corrosion defect data can be classified into three classes using the K-means clustering algorithm,allowing rapid and convenient acquisition of typical size and orientation characteristics of internal corrosion defects;(3)the applicability range and boundary conditions of various NDT techniques were verified,establishing comprehensive selection principles for internal corrosion defect detection technology;(4)on-site inspection results showed a 31%The simulation and validation platform for typical interior corrosion issues greatly enhances the accuracy and reliability of detection data.
文摘The rapid progress in the construction of heavy-haul and high-speed railways has led to a surge in rail defects and unforeseen failures.Addressing this issue necessitates the implementation of more sophisticated rail inspection methods,specifically involving real-time,precise detection,and assessment of rail defects.Current applications fail to address the evolving requirements,prompting the need for advancements.This paper provides a summary of various types of rail defects and outlines both traditional and innovative non-destructive inspection techniques,examining their fundamental features,benefits,drawbacks,and practical suitability for railway track inspection.It also explores potential enhancements to equipment and software.The comprehensive review draws upon pertinent international research and review papers.Furthermore,the paper introduces a fusion of inspection methods aimed at enhancing the overall reliability of defect detection.
基金supported by the National Natural Science Foundation of China(32171354,82222015,82171001)The National Key Research and Development Program of China2023YFC2413600Research Funding from West China School/Hospital of Stomatology,Sichuan University(No.RCDWIS2023-1).
文摘Infectious bone defects represent a substantial challenge in clinical practice,necessitating the deployment of advanced therapeutic strategies.This study presents a treatment modality that merges a mild photothermal therapy hydrogel with a pulsed drug delivery mechanism.The system is predicated on a hydrogel matrix that is thermally responsive,characteristic of bone defect sites,facilitating controlled and site-specific drug release.The cornerstone of this system is the incorporation of mild photothermal nanoparticles,which are activated within the temperature range of 40–43°C,thereby enhancing the precision and efficacy of drug delivery.Our findings demonstrate that the photothermal response significantly augments the localized delivery of therapeutic agents,mitigating systemic side effects and bolstering efficacy at the defect site.The synchronized pulsed release,cooperated with mild photothermal therapy,effectively addresses infection control,and promotes bone regeneration.This approach signifies a considerable advancement in the management of infectious bone defects,offering an effective and patient-centric alternative to traditional methods.Our research endeavors to extend its applicability to a wider spectrum of tissue regeneration scenarios,underscoring its transformative potential in the realm of regenerative medicine.
基金supported by the National Natural Science Foundation of China(52201008,52372003)Natural Science Foundation of Heilongjiang Province of China(ZD2023E004)+1 种基金Fundamental Research Funds for the Central Universities(3072020CF2515,3072022CFJ2504)the State Key Laboratory of Particle Detection and Electronics(SKLPDE-KF-202311)。
文摘Mechano luminescence(ML),which involves the emission of light under mechanical stimuli,shows great potential in various applications such as sensing,imaging,and energy harvesting.Current research suggests that the luminescence mechanism of ML is typically connected to specific defects present within the material.In this study,we focus on the investigation of ML defects in Pr^(3+)-doped NaNbO_(3)/LiNbO_(3)heterojunctions,employing a combination of experimental and theoretical approaches.Through experimental analysis,we confirmed the presence of the heterojunction and its influence on ML intensity,and the optimal doping ratio for the heterojunction in ML was established.Furthermore,we examined the influence of varying Pr^(3+)doping concentrations on ML behavior and a proof-of-concept was demonstrated using the X-rays charged heterostructural phosphor as a stress sensor for biological applications.The position and concentration of internal defects in the ML material were scrutinized through thermo luminescence tests employing the variable heating rate method and positron annihilation.Complementing the experimental findings,theoretical simulations were conducted to elucidate the underlying mechanisms responsible for the observed ML defects.Density functional theory calculations were employed to investigate the energy levels,charge transfer processes,and lattice distortions within the heterojunctions under mechanical stress.Theoretical predictions were compared and validated against the experimental results.The integration of experimental and theoretical approaches provides a comprehensive understanding of the ML behavior of Pr^(3+)-doped NaNbO_(3)/LiNbO_(3)heterojunctions.The insights gained from this research contribute to the development of novel ML materials and pave the way for their applications in next-generation sensing and energy conversion devices.
基金This work is supported by National Natural Science Foundation of China(No.42372054)。
文摘The features of optical defects in a chemical vapor deposition (CVD) synthetic type Ⅱ a diamond were characterized using photoluminescence (PL) spectroscopy, before and after electron irradiation. The sample was cut within a {100} growth layer, and irradiated with 2 MeV electrons along the <100> axis. PL spectra of sample were collected under 532 nm and 355 nm laser excitation, at room temperature and 77 K, and linear scanning analysis along incident depth was applied to determine the distribution of defects. The pre-irradiation characterization results revealed uniformly distributed PL centers at 389 nm, 469 nm, 533 nm, 575 nm (ZPL of NV 0), 637 nm (ZPL of NV -), and 736.7/737.1 nm (ZPL doublet of SiV -). After irradiation, the differential responses of these as-grown defects were observed, alongside the emergence of irradiation-induced defects, namely 489 nm center, H3 center (ZPL at 504 nm) and GR1 center (ZPL at 741 nm). The maximum penetration depth of 2 MeV electron-irradiation induced defects was determined to be 2.1 mm. This work primarily presents the depth profiles of both as-grown and irradiation-induced defects in 2 MeV electrons irradiated diamond. The result provides experimental data for better understanding of the radiation effect in diamonds. Serving as a reference for diamond enhancement by electron irradiation.
基金National Natural Science Foundation of China (62104061, 62074052, 61974173 and 52072327)。
文摘Solution-processed Cu(In,Ga)Se_(2)(CIGS) solar cells suffer from serious carrier recombination and power conversion efficiency(PCE) loss because of the poor film properties and easy formation of defects.Herein, we propose Ag&Se co-selenization strategy to enhance the crystallization and passivate harmful defects of the CIGS films. The formation of Ag-Se phase during the selenization process enables the formation of large grains and suppresses the deep level defects. It is found that Ag doping can enlarge the depletion region width, lower the Urbach energy and prolong the carrier lifetime. As a result, a champion solution-processed CIGS solar cell presents a high efficiency of 16.48% with the highly improved opencircuit voltage(VOC) of 662 m V and fill factor(FF) of 75.8%. This work provides an efficient strategy to prepare high quality solution-processed CIGS films for high-performance CIGS solar cells.
基金supported by Liuchuang Program of Chongqing Municipality(cx2022038)the Fundamental Research Funds for the Central Universities(2022CDJQY-013)the Graduate Research and Innovation Foundation of Chongqing,China(CYB22005).
文摘While early transition metal-based materials,such as MXene,has emerged as an efficient catalyst for the Mg-based hydrogen storage materials,their strong interaction with hydrogen resulted in the high hydrogen diffusion barrier,hindering further improvement of catalytic activity.A MXene is characterized by rich anionic groups on its surface,significantly affecting electronic and catalytic functionalities.Using Nb_(2)CT_(x)as an example,we herein illustrate the critical role of anionic T_(x)defects on controlling hydrogen dissociation and diffusion processes in Mg-based hydrogen storage materials.The hydrogen desorption properties of MgH_(2)can be significantly enhanced by utilizing T_(x)controllable Nb_(2)CT_(x),and it can release 3.57 wt.%hydrogen within 10 min under 240℃with the reduced dehydrogenation activation barrier.It also realized stable de/hydrogenation reactions for at least 50 cycles.DFT studies combined with kinetic analysis revealed that the catalyst‒hydrogen interaction could be systematically controlled by optimizing surface T_(x)defect density,accelerating the hydrogen dissociation and diffusion processes at the same time.These results demonstrate that the T_(x)defects serve as the effective catalytically active centers of Nb_(2)CT_(x),offering a flexible catalyst design guideline.
基金National Natural Science Foundation of China(No.22065038)High-Level Talents Introduction in Yunnan Province(No.C619300A010)+3 种基金the Fund for Excellent Young Scholars of Yunnan(No.202001AW070008)Spring City Plan:the Highlevel Talent Promotion and Training Project of Kunming(No.2022SCP005)for financial supportthe support from the Postdoctoral Research Foundation of Yunnan University(No.W8223004)the Postdoctoral Foundation of Department of Human Resources and Social Security of Yunnan Province(No.C615300504046)。
文摘Defects at the grain boundaries(GBs)of perovskite film highly restrict both the efficiency and stability of perovskite solar cells(PSCs).Herein,organic small molecules of butanedioic acid(BA)and acetylenedicarboxylic acid(AA),containing two carbonyl(C=O)groups and different core-units,were incorporated into perovskite as additives for PSCs application.Thanks to the strong coordination interaction between C=O group and under-coordinated Pb^(2+),the additives can effectively passivate film defects and regulate the perovskite crystallization,yielding high-quality perovskite films with lower defect densities.More importantly,the additives can efficiently regulate the charge transport behaviors in PSCs.Benefiting from the defects passivation and the regulation of charge carrier dynamics,the BA and AA-treaded PSCs show the power conversion efficiencies of 21.52%and 20.50%,which are higher than that of the control device(19.41%).Besides,the optimal devices exhibit a remarkable enhanced long-term stability and moisture tolerance compared to the pristine devices.Furthermore,the transient absorption spectrum reveals the mechanism of enhanced photovoltaic performances,attributing to the improvement of charge transport capability at the perovskite/Spiro-OMeTAD interfaces.This work affords a promising strategy to improve the efficiency and stability of PSCs through regulating the charge-carrier dynamic process in perovskite film.
文摘Following publication of the original article[1],the authors found that they pasted the same data when drawing XRD for sample NCO-1 and NCO-2 in Fig.2a,however,the XRD of all four samples in the manuscript was tested,and XRD raw data were kept and can be offered.The correct Fig.2 has been provided in this Correction.
基金financial support from the National Natural Science Foundation of China(No.12474016)the program of“Distinguished Expert of Taishan Scholar”(No.tstp20221124)+4 种基金the National Natural Science Foundation of China(Nos.52172212,12474017)the Shandong Provincial Science Foundation(ZR2021YQ03)the program for“Young Scientists of Taishan Scholars”(No.tsqn202306184)financial support from the National Natural Science Foundation of China(No.12464034)the Natural Science Foundation of Ningxia,China(No.2024AAC05070)。
文摘Defect engineering is a commonly methodology used to enhance the thermoelectric performance of thermoelectric PbTe by improving its electronic transport properties.At the nanoscale,defects can induce quantum tunneling effects that significantly impact the electrical properties of materials.To understand the specific mechanisms underlying the quantum transport properties of PbTe,we employ the non-equilibrium Green's function(NEGF)method to investigate the effects of intrinsic defects(point defects and grain boundaries)on the electronic transport properties of PbTe-based nanodevices from a quantum mechanical perspective.Our results show that the Pb vacancy(VPb)has the highest conduction.The conduction depends on the defect type,chemical potential and bias voltage.The presence of intrinsic point defects introduces impurity levels,facilitating the electron tunneling and leading to an increase in the transmission coefficient,thereby enhancing the electronic transport properties.For PbTe containing grain boundaries,these boundaries suppress the electronic transport properties.The Te occupied twin boundary(Te-TB)exerts a stronger inhibitory effect than the Pb occupied twin boundary(Pb-TB).Nevertheless,the combined effect between twin boundaries and point defects can enhance the electrical properties.Therefore,in order to obtain highly conductive of PbTe materials,a Te-rich synthesis environment should be used to promote the effective formation of Pb vacancy.Our work offers a comprehensive understanding of the impact of defects on electron scattering in thermoelectric materials.
基金National Natural Science Foundation of China(Grant No.52408314)Science and Technology Project of Sichuan Provincial TransportationDepartment(GrantNo.2023-ZL-03)Science and Technology Project of Guizhou Provincial Transportation Department(Grant No.2024-122-018).
文摘Failure tests were conducted on two concrete-filled steel tubular(CFST)truss arch bridges with a span of approximately 12 m to investigate the influence of initial geometric defects on the in-plane bearing capacity of CFST truss arch bridges.The effects of antisymmetric defect on the ultimate bearing capacity,failure mode,structural response,and steel–concrete confinement effect of CFST truss arch bridges under quarter-point loading were analyzed.On this basis,numerical simulations were conducted to investigate the in-plane bearing capacity of CFST truss arch bridges further under different scenarios.The initial defect formof the archwas obtained by using theoretical deduction,and the theoretical basis for the weakening of the ultimate bearing capacity of the arch bridge caused by geometric defects was clarified.Results indicate that the antisymmetric defect does not change the four-hinge failure mode of the model arch under quarter-point loading but increases the local cracking area and crack density of the concrete inside the pipe.The sine geometric defect with an amplitude of L/250 resulted in a 44.4%decrease in the yield load of the single hinge of the model arch,a 10.5%decrease in the failure load of the four hinges,and a 40.9%increase in themaximum vertical deformation during failure.At the initial stage of loading,the steel pipe and the concrete inside the pipe were subjected to relatively independent forces.After reaching 67%of the ultimate load,the catenary arch ribs began to produce a steel pipe concrete constraint effect.The initial geometric defects resulted in a decrease in the load when the constraint effect occurred.The antisymmetric defects with the same amplitude have a greater impact on the in-plane bearing capacity of the CFST arch bridge than the initial geometric defects with symmetry.The linear deviation at L/4 caused by constructionmust be controlled to be less than L/600 to ensure that the internal bearing capacity of the CFST arch bridge reaches 95%of the design bearing capacity.The structural deformation caused by geometric initial defects increases linearly with the increase in defect amplitude.The bearing capacity is weakened because the structural deflection and bending moment are amplified by initial defects.
基金support from the Open Research Project Programme of the State Key Laboratory of Internet of Things for Smart City,University of Macao (Grant No.SKL-IoTSC (UM)-2021-2023/ORPF/A19/2022)the General Research Fund project from Research Grants Council of Hong Kong Special Administrative Region Government of China (Grant No.15214722)the Start-up Fund from The Hong Kong Polytechnic University (Grant No.BD88).
文摘Despite the extensive use of distributed fiber optic sensing(DFOS)in monitoring underground structures,its potential in detecting structural anomalies,such as cracks and cavities,is still not fully understood.To contribute to the identification of defects in underground structures,this study conducted a four-point bending test of a reinforced concrete(RC)beam and uniaxial loading tests of an RC specimen with local cavities.The experimental results revealed the disparity in DFOS strain spike profiles between these two structural anomalies.The effectiveness of DFOS in the quantification of crack opening displacement(COD)was also demonstrated,even in cases where perfect bonding was not achievable between the cable and structures.In addition,DFOS strain spikes observed in two diaphragm wall panels of a twin circular shaft were also reported.The most probable cause of those spikes was identified as the mechanical behavior associated with local concrete contamination.With the utilization of the strain profiles obtained from laboratory tests and field monitoring,three types of multi-classifiers,based on support vector machine(SVM),random forest(RF),and backpropagation neural network(BP),were employed to classify strain profiles,including crack-induced spikes,non-crack-induced spikes,and non-spike strain profiles.Among these classifiers,the SVM-based classifier exhibited superior performance in terms of accuracy and model robustness.This finding suggests that the SVM-based classifier holds promise as a potential solution for the automatic detection and classification of defects in underground structures during long-term monitoring.
基金supported by the National Key Research and Development Program,Ministry of Science and Technology of the People's Republic of China(Grant No.2021YFC2701001)the National Natural Science Foundation of China(Grant No.81973056).
文摘Objective Exposure to polycyclic aromatic hydrocarbons(PAHs)or metal(loid)s individually has been associated with neural tube defects(NTDs).However,the impacts of PAH and metal(loid)co-exposure and potential interaction effects on NTD risk remain unclear.We conducted a case-control study in China among population with a high prevalence of NTDs to investigate the combined effects of PAH and metal(loid)exposures on the risk of NTD.Methods Cases included 80 women who gave birth to offspring with NTDs,whereas controls were 50 women who delivered infants with no congenital malformations.We analyzed the levels of placental PAHs using gas chromatography and mass spectrometry,PAH-DNA adducts with 32P-post-labeling method,and metal(loid)s with an inductively coupled plasma mass spectrometer.Unconditional logistic regression was employed to estimate the associations between individual exposures and NTDs.Least absolute shrinkage and selection operator(LASSO)penalized regression models were used to select a subset of exposures,while additive interaction models were used to identify interaction effects.Results In the single-exposure models,we found that eight PAHs,PAH-DNA adducts,and 28 metal(loid)s were associated with NTDs.Pyrene,selenium,molybdenum,cadmium,uranium,and rubidium were selected through LASSO regression and were statistically associated with NTDs in the multiple-exposure models.Women with high levels of pyrene and molybdenum or pyrene and selenium exhibited significantly increased risk of having offspring with NTDs,indicating that these combinations may have synergistic effects on the risk of NTDs.Conclusion Our findings suggest that individual PAHs and metal(loid)s,as well as their interactions,may be associated with the risk of NTDs,which warrants further investigation.
基金supported by National Key Research and Development Program of China(Grant No.2021YFB3702502)National Natural Science Foundation of China(Grant Nos.52271035,and 52474412)+1 种基金Natural Science Foundation of Shanghai,China(Grant No.23ZR1421500)the SPMI Project from Shanghai Academy of Spaceflight Technology(Grant No.SPMI2022-06).
文摘Intermetallic alloys offer exceptional high-temperature mechanical properties and low densities,thus rendering them suitable for a wide range of applications in aviation and spacecraft.However,their inherent brittleness at room temperature poses challenges in the manufacture of complex geometries.Hence,Laser additive manufacturing(LAM)has emerged as a promising approach to investigate the potential limitations of these materials.This review discusses the key findings and challenges associated with the LAM of intermetallic alloys,particu-larly NiAl,Ni_(3)Al,and TiAl,whose engineering applications are substantial.It provides an overview of typical defect morphologies,formation mechanisms,and strategies to prevent cracks and pores.Additionally,it presents an analysis of the microstructural characteristics of as-built and post-treated samples compared with those of samples prepared conventionally.Furthermore,the mechanical properties of the above-mentioned alloys at both room and high temperatures are reviewed,thus highlighting the effects of post-treatment processes.This review concludes with summary tables detailing the mechanical properties,which serve as useful references for researchers.
基金supported by the National Natural Science Foundation of China[81801007]the Traditional Chinese Medicine Bureau of Guangdong Province[20242062]+2 种基金the Major of Basic and Applied Basic Research Project of Guangzhou City[202201011601]the Science and Cultivation Foundation of Stomatological Hospital of Southern Medical University[PY2021016]the Guangdong Province Clinical Teaching Base Teaching Reform Research Project[2023JD054].
文摘The regeneration of infected bone defects is still challenging and time-consuming,due to the adverse osteogenic microenvironment caused by bacterial contamination and pronounced ischemia.Biodegradable magnesium(Mg)-based alloys are desirable for orthopedic implants due to the mechanical properties approximating those of human bone and the released Mg^(2+)ions essential to osteogenic activity.However,the fast and uncontrolled self-degradation of Mg alloy,along with the inadequate antimicrobial activity,limit their strength in the osteogenic microenvironment.Inspired by the structural and physiological characteristics of“fish scales,”two-dimensional(2D)nanomaterials,black phosphorus(BP)and graphene oxide(GO),were assembled together under the action of pulsed electric field.The bionic 2D layered BP/GO nano-coating was constructed for infection resistance,osteogenic microenvironment optimization,and biodegradation control.In the early stage of implantation,it exerted a photothermal effect to ablate bacterial biofilms and avoid contaminating the microenvironment.The blocking effect of the“nano fish scales”-2D material superposition regulated the degradation of implants.In the later stage,it attracted the migration of vascular endothelial cells(VECs)and released phosphate slowly for in situ mineralization to create the microenvironment favoring vascularized bone formation.It is indicated that the enhancement of microtubule deacetylation and cytoskeletal reorganization played a key role in the effect of VEC migration and angiogenesis.This study provided a promising bionic strategy for creating osteogenic microenvironments that match the sequential healing process of infected bone defects.
基金funded by the National Natural Science Foundation of China (Grant No. 52178402 & 52378468)the Open Foundation of MOE Key Laboratory of Engineering Structures of Heavy Haul Railway (Central South University) (Grant No. 2022JZZ01)+1 种基金the National Engineering Research Center for High-Speed Railway Construction Technology for their project supportthe support from the MOE Key Laboratory of Engineering Structure of Heavy Haul Railway (Central South University)
文摘With the rapid development of heavy haul railway transportation technology,tunnel foundation defects and their effects on structural performance have attracted wide attention.This paper systematically investigates the evolution mechanism of tun-nel foundation defects in heavy haul railway tunnels and their impact on structural stiffness degradation through experiments and numerical simulations.A heavy haul train-ballasted track-tunnel basement-surround rock dynamic interaction model(TTTR model)is constructed.Firstly,the study reveals the four-stage evolution process of initial defects in the tunnel base-ment under complex environmental conditions.Experiments were conducted to measure the load-bearing capacity and stiff-ness degradation of the tunnel basement structure under different defect states.It is found that foundation defects,especially under the coupling of loose fill in the basement with the water-rich environment of the surrounding rock,significantly reduce the stiffness of the tunnel bottom structure and increase the risk of structural damage.Then,based on refined simulation of wheel-rail interaction and multi-scale coupled modeling technology,the TTTR dynamic interaction model was successfully constructed,and its validity was proven through numerical validation.A time-varying coupling technique of constrained boundary substructures(CBS technique)was adopted,significantly improving computational efficiency while ensuring calculation accuracy.The study also analyzes the effects of different degrees of void defects on the dynamic behavior of the train and the dynamic characteristics of the tunnel structure.It finds that foundation defects have a significant impact on the train’s operational state,track vibration displacement,and vibration stress of the tunnel lining structure,especially under the coupling effect of basement voids and the water-rich environment,which has the greatest impact.The research results of this paper provide a theoretical basis and technical support for the maintenance and reinforcement of tunnel foundation structures.
文摘BACKGROUND The generation of intrabony defects due to the iatrogenic use of elastic bands is an undesirable situation that can result in persistent gingival inflammation with subsequent bone degradation,thus ultimately leading to tooth loss.CASE SUMMARY This clinical case involved a 27-year-old male patient who complained of persistent inflammation and bleeding in the upper anterior region of the gums,despite having undergone dental cleaning for at least 4 years.The dental and medical history indicated the use of removable orthodontic appliances for 8 years,after which braces were placed for 2 years.The intraoral evaluation revealed inflammation and localized suppuration in teeth 11 and 12.Measurements of 2-7 mm for probing depth and 1-5 mm for clinical attachment loss were detected,and combined bone loss was observed via radiographs.Based on the clinical and radiographic findings,localized stage III,grade C periodontitis was diagnosed.During subgingival debridement,two elastic bands emerged around the involved teeth.The bone defects persisted;therefore,they were surgically addressed using a papilla preservation flap and guided tissue regeneration(GTR).CONCLUSION The use of elastic bands of various sizes and elasticities is often essential in multiple orthodontic treatments.However,it is crucial to perform a thorough check-up for each patient during treatment and at the end of treatment to remove any remaining residue of resin,metal bands,or orthodontic bands.Additionally,it is imperative to inform the patients of the importance of attending their follow-up appointments.The use of elastic bands in orthodontics requires special care;moreover,GTR is a management option for intrabony defects associated with the iatrogenic use of bands.
