Attempts have been made to modulate motor sequence learning(MSL)through repetitive transcranial magnetic stimulation,targeting different sites within the sensorimotor network.However,the target with the optimum modula...Attempts have been made to modulate motor sequence learning(MSL)through repetitive transcranial magnetic stimulation,targeting different sites within the sensorimotor network.However,the target with the optimum modulatory effect on neural plasticity associated with MSL remains unclarified.This study was therefore designed to compare the role of the left primary motor cortex and the left supplementary motor area proper(SMAp)in modulating MSL across different complexity levels and for both hands,as well as the associated neuroplasticity by applying intermittent theta burst stimulation together with the electroencephalogram and concurrent transcranial magnetic stimulation.Our data demonstrated the role of SMAp stimulation in modulating neural communication to support MSL,which is achieved by facilitating regional activation and orchestrating neural coupling across distributed brain regions,particularly in interhemispheric connections.These findings may have important clinical implications,particularly for motor rehabilitation in populations such as post-stroke patients.展开更多
The"Talk to the Plants"course,as an interdisciplinary integrated teaching innovation practice course,aims to break through the knowledge-imparting model of traditional botany education.It establishes a profo...The"Talk to the Plants"course,as an interdisciplinary integrated teaching innovation practice course,aims to break through the knowledge-imparting model of traditional botany education.It establishes a profound interactive bridge between humans and plants,cultivating students'ecological awareness,scientific literacy,and humanistic values.With life education at its core,the course integrates multidisciplinary knowledge from botany,ecology,psychology,and arts.Leveraging modern technologies including VR/AR and sensor monitoring,it creates immersive learning environments that guide students to engage with plants through scientific inquiry,emotional empathy,and artistic expression.This exploration establishes a new paradigm for developing well-rounded talents in ecological civilization while offering both theoretical insights and practical models for interdisciplinary curriculum reform in the new era,demonstrating significant value in educational innovation.展开更多
Heat dissipation highly relies on the thermal conductivity(κ)of materials.Materials with large bandgaps and signifcant atomic mass ratios,such as BAs,SiC,andθ-TaN,have attracted considerable attention due to their p...Heat dissipation highly relies on the thermal conductivity(κ)of materials.Materials with large bandgaps and signifcant atomic mass ratios,such as BAs,SiC,andθ-TaN,have attracted considerable attention due to their potential for achieving ultra-highκ,with BAs serving as a particularly representative example due to its unique combination of large bandgap and high thermal conductivity.In this paper,the efects of atomic mass modifcation on phonon bandgap andκare systematically investigated using a BAs model,accounting for both three-and four-phonon scattering processes.A 20%increase inκcan be obtained by substituting B,achieved through widening the phonon bandgap,which suppresses phonon scattering.Notably,the AAOO four-phonon scattering channel is more suppressed than the AAO three-phonon channel,leading to an increased phonon lifetime(τ).For As,κcan also be enhanced by 5%when replaced by lighter atoms,such as^(69)As,primarily due to the increased phonon group velocity(υ).We systematically clarify how atomic-mass-induced bandgap variations afectτ,υ,and thereforeκin wide-bandgap systems.Our work provides a specifc scheme for further improving the ultra-highκof materials with large bandgaps,which possesses great guiding signifcance.展开更多
Objective:Allogeneic hematopoietic stem cell transplantation(allo-HSCT)is the only potentially curative method for treating myelodysplastic syndrome(MDS).Post-HSCT measurable residual disease(post-HSCT MRD)is associat...Objective:Allogeneic hematopoietic stem cell transplantation(allo-HSCT)is the only potentially curative method for treating myelodysplastic syndrome(MDS).Post-HSCT measurable residual disease(post-HSCT MRD)is associated with inferior transplant outcomes.In this prospective study,we aimed to investigate the prognostic value of post-HSCT MRD in relapse prediction in MDS.Methods:A total of 166 patients diagnosed with MDS were prospectively enrolled in this study.The KaplanMeier method was used to calculate the survival probabilities.Potential risk factors for outcomes after transplantation were evaluated through univariate and multivariate Cox regression models.Results:For patients with negative and positive post-HSCT MRD,the cumulative incidence of relapse(CIR)and disease-free survival(DFS)at 3 years were 5.9%and 69.6%(P<0.001)and 82.7%and 26.1%(P<0.001),respectively.In the multivariate analysis,post-HSCT MRD(HR=22.801,P<0.001)and Revised International Prognostic Scoring System(IPSS-R)risk stratification(HR=4.346,P=0.003)were independently correlated with relapse.A scoring system for relapse prediction was built based on post-HSCT MRD and IPSS-R stratification.The cumulative incidence of relapse at 3 years was 1.1%,15.8%,and 91.7%for patients with scores of 0,1,and 2,respectively(P<0.001).Conclusions:Our results demonstrated both post-HSCT MRD and IPSS-R scores were independent prognostic factors for OS,DFS,and relapse for MDS patients after allo-HSCT.The risk score system could better predict transplant outcomes and refine the risk stratification than alone in patients with MDS.展开更多
Chemical short-range order(SRO),a phenomenon at the atomic scale resulting from inhomogeneities in the local chemical environment,is usually studied using machine learning force field-based molecular dynamics simulati...Chemical short-range order(SRO),a phenomenon at the atomic scale resulting from inhomogeneities in the local chemical environment,is usually studied using machine learning force field-based molecular dynamics simulations due to the limitations of experimental methods.To promote the reliable application of machine potentials in high-entropy alloy simulations,first,this work uses NEP models trained on two different datasets to predict the SRO coefficients of NbMoTaW.The results show that within the same machine learning framework,there are significant differences in the prediction of SRO coefficients for the Nb-Nb atomic pair.Subsequently,this work predicts the SRO coefficients of NbMoTaW using the NEP model and the SNAP model,both of which are trained on the same dataset.The results reveal significant discrepancies in SRO predictions for like-element pairs(e.g.,Nb-Nb and W-W)between the two potentials,despite the identical training data.The findings of this study indicate that discrepancies in the prediction results of SRO coefficients can arise from either the same machine learning framework trained on different datasets or different learning frameworks trained on the same dataset.This reflects possible incompleteness in the current training set's coverage of local chemical environments at the atomic scale.Future research should establish unified evaluation standards to assess the capability of training sets to accurately describe complex atomic-scale behaviors such as SRO.展开更多
Accurate daily suspended sediment load(SSL)prediction is essential for sustainable water resource management,sediment control,and environmental planning.However,SSL prediction is highly complex due to its nonlinear an...Accurate daily suspended sediment load(SSL)prediction is essential for sustainable water resource management,sediment control,and environmental planning.However,SSL prediction is highly complex due to its nonlinear and dynamic nature,making traditional empirical models inadequate.This study proposes a novel hybrid approach,integrating the Adaptive Neuro-Fuzzy Inference System(ANFIS)with the Gradient-Based Optimizer(GBO),to enhance SSL forecasting accuracy.The research compares the performance of ANFIS-GBO with three alternative models:standard ANFIS,ANFIS with Particle Swarm Optimization(ANFIS-PSO),and ANFIS with Grey Wolf Optimization(ANFIS-GWO).Historical SSL and streamflow data from the Bailong River Basin,China,are used to train and validate the models.The input selection process is optimized using the Multivariate Adaptive Regression Splines(MARS)method.Model performance is evaluated using statistical metrics such as Root Mean Square Error(RMSE),Mean Absolute Error(MAE),Mean Absolute Percentage Error(MAPE),Nash Sutcliffe Efficiency(NSE),and Determination Coefficient(R^(2)).Additionally,visual assessments,including scatter plots,Taylor diagrams,and violin plots,provide further insights into model reliability.The results indicate that including historical SSL data improves predictive accuracy,with ANFIS-GBO outperforming the other models.ANFIS-GBO achieves the lowest RMSE and MAE and the highest NSE and R^(2),demonstrating its superior learning ability and adaptability.The findings highlight the effectiveness of nature-inspired optimization algorithms in enhancing sediment load forecasting and contribute to the advancement of AI-based hydrological modeling.Future research should explore the integration of additional environmental and climatic variables to enhance predictive capabilities further.展开更多
The increasing global adoption of electric vehicles(EVs)has led to a growing demand for a cost-effective and reliable charging infrastructure.This study presents a novel data-driven approach to assessing EV station pe...The increasing global adoption of electric vehicles(EVs)has led to a growing demand for a cost-effective and reliable charging infrastructure.This study presents a novel data-driven approach to assessing EV station performance by analyzing power consumption efficiency,station utilization rates,no-power session occurrences,and CO_(2)reduction metrics.A dataset of 17,500 charging sessions from 305 stations across a regional network was analyzed to identify operational inefficiencies and opportunities for infrastructure optimization.Results indicate a strong correlation between station utilization and energy efficiency,highlighting the importance of strategic station placement.The findings also emphasize the impact of no-power sessions on network inefficiency and the need for real-time station monitoring.CO_(2)reduction analysis demonstrates that optimizing EV charging performance can significantly contribute to sustainability goals.Based on these insights,this study recommends the implementation of predictive maintenance strategies,real-time user notifications,and diversified provider networks to improve station availability and efficiency.The proposed data-driven framework offers actionable solutions for policymakers,charging network operators,and urban planners to enhance EV infrastructure reliability and sustainability.展开更多
Perovskite solar cells(PSCs)have emerged as promising photovoltaic technologies owing to their remarkable power conversion efficiency(PCE).However,heat accumulation under continuous illumination remains a critical bot...Perovskite solar cells(PSCs)have emerged as promising photovoltaic technologies owing to their remarkable power conversion efficiency(PCE).However,heat accumulation under continuous illumination remains a critical bottleneck,severely affecting device stability and long-term operational performance.Herein,we present a multifunctional strategy by incorporating highly thermally conductive Ti_(3)C_(2)T_(X) MXene nanosheets into the perovskite layer to simultaneously enhance thermal management and optoelectronic properties.The Ti_(3)C_(2)T_(X) nanosheets,embedded at perovskite grain boundaries,construct efficient thermal conduction pathways,significantly improving the thermal conductivity and diffusivity of the film.This leads to a notable reduction in the device’s steady-state operating temperature from 42.96 to 39.97 under 100 mW cm^(−2) illumination,thereby alleviating heat-induced performance degradation.Beyond thermal regulation,Ti_(3)C_(2)T_(X),with high conductivity and negatively charged surface terminations,also serves as an effective defect passivation agent,reducing trap-assisted recombination,while simultaneously facilitating charge extraction and transport by optimizing interfacial energy alignment.As a result,the Ti_(3)C_(2)T_(X)-modified PSC achieve a champion PCE of 25.13%and exhibit outstanding thermal stability,retaining 80%of the initial PCE after 500 h of thermal aging at 85 and 30±5%relative humidity.(In contrast,control PSC retain only 58%after 200 h.)Moreover,under continuous maximum power point tracking in N2 atmosphere,Ti_(3)C_(2)T_(X)-modified PSC retained 70%of the initial PCE after 500 h,whereas the control PSC drop sharply to 20%.These findings highlight the synergistic role of Ti_(3)C_(2)T_(X) in thermal management and optoelectronic performance,paving the way for the development of high-efficiency and heat-resistant perovskite photovoltaics.展开更多
Five pure metals including Fe, Mn, Mg, Zn and W have been investigated on their corrosion behavior and in vitro biocompatibility by electrochemical measurement, static immersion test, contact angle measurement, cytoto...Five pure metals including Fe, Mn, Mg, Zn and W have been investigated on their corrosion behavior and in vitro biocompatibility by electrochemical measurement, static immersion test, contact angle measurement, cytotoxicity and hemocompatibility tests. It is found that the sequence of corrosion rate of five metals in Hank's solution from high to low is: Mg 〉 Fe 〉 Zn 〉 Mn 〉 W. Fe, Mg and W show no cytotoxicity to L929 and ECV304 cells, Mn induces significant cytotoxicity to both L929 and ECV304 cells, and Zn has almost no inhibition effect on the metabolic activities of ECV304 while largely reduces the cell viability of L929 cells. The hemolysis percentage of five pure metals is lower than 5% except for Mg and platelets adhered on Zn has been activated and pseudopodia-like structures can be observed while platelets on the other four metals keep normal.展开更多
AZ31 magnesium alloy fibers reinforced poly(lactic-co-glycolic acid) (PLGA) composites were prepared and their mechanical property, immersion corrosion behavior and biocompatibility were studied. The tensile test ...AZ31 magnesium alloy fibers reinforced poly(lactic-co-glycolic acid) (PLGA) composites were prepared and their mechanical property, immersion corrosion behavior and biocompatibility were studied. The tensile test showed that with the addition of AZ31 fibers, the composites had a significant increment in tensile strength and elongation. For the direct cell attachment test, all the cells showed a healthy morphology and spread well on the experimental sample surfaces. The immersion results indicated that pH values of the immersion medium increased with increasing AZ31 fiber contents. All the in vitro experimental results indicated that this new kind of magnesium alloy fibers reinforced PLGA composites show a potential for future biomedical applications.展开更多
The mechanical properties, chemical properties and biocompatibility of Mg-3Sn-0.5Mn alloy were tested. A series of in vitro evaluations such as tensile test, static and dynamic immersion test, hemocompatibility test a...The mechanical properties, chemical properties and biocompatibility of Mg-3Sn-0.5Mn alloy were tested. A series of in vitro evaluations such as tensile test, static and dynamic immersion test, hemocompatibility test as well as cytotoxicity test were presented, with commercial magnesium alloy WE43 as the control. Mg-3Sn-0.5Mn alloy possesses suitable strength and superior ductility compared with WE43 and AZ31. Static immersion and dynamic degradation tests showed more uniform degradation with a more moderate rate for Mg-3Sn-0.5Mn alloy (0.34 mm/y in static condition and 0.25 mm/y in dynamic condition) compared with WE43 alloy (0.42 mm/y in static condition and 0.33 mm/y in dynamic condition) in Hank's solution. Blood compatibility evaluation suggested that Mg-3Sn-0.5Mn alloy had no destructive effect on erythrocyte and showed excellent anti-thrombogenicity to blood system. Besides, Mg-3Sn-0.5Mn alloy showed no inhibition effect to L929 metabolic activity and mild toxicity to vascular smooth muscle cell (VSMC) in preliminary cell viability assessment. By considering its excellent mechanical strength, corrosion resistance, low ion release rate and good biocompatibility, Mg-3Sn-0.5Mn alloy may be a promising economical candidate as biomedical implant material for load-bearing clinical applications in the future.展开更多
In recent years, machine learning(ML) techniques have emerged as powerful tools for studying many-body complex systems, and encompassing phase transitions in various domains of physics. This mini review provides a con...In recent years, machine learning(ML) techniques have emerged as powerful tools for studying many-body complex systems, and encompassing phase transitions in various domains of physics. This mini review provides a concise yet comprehensive examination of the advancements achieved in applying ML to investigate phase transitions, with a primary focus on those involved in nuclear matter studies.展开更多
An algorithm named InterOpt for optimizing operational parameters is proposed based on interpretable machine learning,and is demonstrated via optimization of shale gas development.InterOpt consists of three parts:a ne...An algorithm named InterOpt for optimizing operational parameters is proposed based on interpretable machine learning,and is demonstrated via optimization of shale gas development.InterOpt consists of three parts:a neural network is used to construct an emulator of the actual drilling and hydraulic fracturing process in the vector space(i.e.,virtual environment);:the Sharpley value method in inter-pretable machine learning is applied to analyzing the impact of geological and operational parameters in each well(i.e.,single well feature impact analysis):and ensemble randomized maximum likelihood(EnRML)is conducted to optimize the operational parameters to comprehensively improve the efficiency of shale gas development and reduce the average cost.In the experiment,InterOpt provides different drilling and fracturing plans for each well according to its specific geological conditions,and finally achieves an average cost reduction of 9.7%for a case study with 104 wells.展开更多
The encapsulation of essential oil components in cyclodextrins(CDs)to form inclusion complexes(ICs)is an effective strategy for improving their stability and bioaccessibility.The aim of the present study was to obtain...The encapsulation of essential oil components in cyclodextrins(CDs)to form inclusion complexes(ICs)is an effective strategy for improving their stability and bioaccessibility.The aim of the present study was to obtain a deeper understanding of the encapsulation behavior of multi-components inβ-CD.vip molecules ofα-pinene,myrcene,and 3-carene,having the same molecular weight,formed ICs withβ-CD by a freeze-drying method.A simplex lattice mixture design with 28 experiments was carried out.Statistical analysis was applied to analyze the encapsulation behavior of vip components,and quantitative models of vip components in ICs were constructed by coupling with near-infrared(NIR)spectroscopy and chemometrics analysis.Besides,the molecular docking technique was used to obtain the optimal conformation and explain the binding behavior of inclusion.The results suggested that the spatial structure and ratio of vip molecules were the key factors affecting the encapsulation effect.A non-destructive and rapid NIR analytical model for the vip component in ICs could be obtained by second derivative(2nd der)pretreatment.Collectively,the encapsulation of vip components inβ-CD was differentiated,and NIR could be used as a rapid and non-destructive tool for quantitative analysis of ICs.展开更多
One of the major problems of modern neurobiology is how to replace dead or damaged neurons in the human brain or spinal cord after injury or as a consequence of neurodegenerative dis- eases. In fact, because adult mam...One of the major problems of modern neurobiology is how to replace dead or damaged neurons in the human brain or spinal cord after injury or as a consequence of neurodegenerative dis- eases. In fact, because adult mammalian neurons are post-mi- totic cells that cannot divide to replace dead cells, loss due to lesion or disease is permanent. Furthermore, surviving neurons have modest capacity to regenerate their damaged axons and re-establish functional connections. Thus, a gradual neurode- generative scenario with certain similarities in stroke, brain or spinal cord injuries and neurological diseases like Alzheimer's disease is produced. These conditions represent the major disease burden of the modern world in terms of mortality, dis- ability, productivity loss and health-care costs (World Health Organization, 2008). While much effort has been directed to understand the molecular and cellular mechanisms involved in the pathology of these diseases to set new effective treatments, many neuroprotective and regenerative approaches, although showing positive results in preclinical studies, have so far failed to provide strong benefit to patients.展开更多
The planetary theory in the Great Expansion System(Dayan li大衍历,727 CE)is investigated,with a detailed example of Mars.In ancient Chinese astrology,the position of one planet and the relative positions of different ...The planetary theory in the Great Expansion System(Dayan li大衍历,727 CE)is investigated,with a detailed example of Mars.In ancient Chinese astrology,the position of one planet and the relative positions of different planets had important astrological significance.Thus,planetary theory is an important part of Chinese mathematical astronomy.The Great Expansion System,which was compiled by Yixing一行of the Tang唐dynasty(618–907 CE),provided many innovations in planetary theory.Based on the extant Treatises on Mathematical Harmonics and Astronomy(Lüli zhi律历志)in Chinese official histories,the Great Expansion System was the first Chinese astronomical system to include tables of the planetary equation of center and procedures for correcting the influence of the planetary equation of center on the position of a planet.It was also the first Chinese system to design a table of the planetary phases of motion for calculating the mean position of a planet,which was the basis for calculating the true position of the planet.In addition,Yixing proposed the concept of the precession of planetary perihelion and gave the values of the precession of planetary perihelion for the first time in ancient China.The innovations of the Great Expansion System regarding planetary theory established its important position in the history of Chinese astronomical systems.Mars is taken as a case study to investigate the planetary theory in the Great Expansion System,including the astronomical constants related to Mars,two important astronomical tables,namely the table of the equation of center and the table of the phase motion of Mars in one synodic period,and the procedures for calculating the position of Mars on any given day using the planetary and solar equations of center.Two questions are addressed.First,how did Yixing correct the influence of the equation of center of Mars on the time of mean conjunction and the mean position of Mars?Second,how did Yixing calculate the true position of Mars on any given day?The original text of the Great Expansion System is analyzed to show how Yixing developed the planetary theory in the Sui and early Tang periods and constructed a complete method for predicting the true positions of planets using the planetary and solar equations of center.展开更多
Quantitative investigation on mechanical characteristics of cardiac myocytes has important physiological significance. Based on elastic substrate technique, this paper develops a set of algorithms for high-efficiency ...Quantitative investigation on mechanical characteristics of cardiac myocytes has important physiological significance. Based on elastic substrate technique, this paper develops a set of algorithms for high-efficiency cellular traction recovery. By applying a gradient-based digital image correlation method to track randomly distributed fluorescence microbeads on the deformed substrate induced by single cardiac myocyte, high-resolution substrate displacement field can readily be obtained. By using a numerical algorithm based on the integral Boussinesq solution, cell-substrate tractions are reconstructed in a stable and reliable manner. Finally, spatiotemporal dynamics of a single cardiac myocyte is investigated as it adheres to a polyacrylamide elastic substrate.展开更多
We investigated the bacterioplankton abundance, community composition and the associated Vibrio clades of natural seawater in Bohai Sea coastal waters. Seawater samples (10 L in triplicate) were collected at 0.5, 3, a...We investigated the bacterioplankton abundance, community composition and the associated Vibrio clades of natural seawater in Bohai Sea coastal waters. Seawater samples (10 L in triplicate) were collected at 0.5, 3, and 5 m depths near the coastal aquaculture zone of the Bohai Sea on May 12, 2016. Real-time PCR and 16S rRNA gene amplicon high-throughput sequencing methods were employed by which 485 operational taxonomic units (OTUs) at a 97% sequence similarity level were generated. Gammaproteobacteria, Alphaproteobacteria, and Bacteroidetes were the most abundant groups, accounting for 49.5%, 23.5%, and 18.9% of the total assemblage, respectively. Obvious variations in Pseudoalteromonas, Vibrio, and Octadecabacter , which were the most abundant genera, could be observed among diff erent samples. Notably, the results of Vibrio -specifi c real-time PCR indicated that Vibrio had extremely high 16S rRNA gene copy numbers. The 16S rRNA gene sequencing results across all the samples also indicated that they occupied a large proportion of the total assemblage. Both the alpha diversity and major bacterioplankton group Pseudoalteromonas had significant correlations with the concentration of PO4^3-. Overall, studies on bacterioplankton communities with highly abundant Vibrio clades can provide interesting insight into the microbial function and health assessment of the Bohai Sea coastal ecosystem.展开更多
Inconel 738 LC samples were fabricated using laser powder bed fusion under continuous-wave and pulsed-wave modes.Microstructure,surface quality and mechanical properties were compared to evaluate the printing quality ...Inconel 738 LC samples were fabricated using laser powder bed fusion under continuous-wave and pulsed-wave modes.Microstructure,surface quality and mechanical properties were compared to evaluate the printing quality between these 2 laser beam modes.The results show that the application of pulsed wave could effectively eliminate cracking in the as-fabricated sample,despite 0.046%porosity generated.Further microstructure analysis revealed that the refinement of grains by the pulsed-wave laser beam was the main contributor in eliminating the cracks.And this refinement was ascribed to the higher cooling rate under the discontinuous radiation of laser beam proofed by the numerical simulation.And the pore formation was related to Rayleigh instability and residual bubbles in the sample under the pulsed-wave mode,while pores were less detrimental to the mechanical properties than cracks.Therefore,the part under the pulsed-wave mode exhibited superior mechanical performance compared to that under the continuous-wave mode.展开更多
In this study, in order to explain the solvent and spin state effects on the molecular structure of catechol-Fe complex [Fe(cat)3]n﹣?where n = 2 and 3, Hartree Fock (HF)-Density Functional Theory (DFT) hybrid calcula...In this study, in order to explain the solvent and spin state effects on the molecular structure of catechol-Fe complex [Fe(cat)3]n﹣?where n = 2 and 3, Hartree Fock (HF)-Density Functional Theory (DFT) hybrid calculations are performed at the B3LYP/6-311g(d,p) level of theory. The binding energies of Fe2+ and Fe3+ in high-spin state are higher than intermediate and low-spin states which show that the complex formation in a high spin state is more favorable. The calculated binding energies at different solvents indicate that the binding energies in polar solvents are lower than non-polar solvents. Furthermore, spectroscopic studies including FTIR and Raman spectrum in various solvents reveal that the formation of intermolecular bonds between the oxygen atom of carbonyl group and the hydrogen atom of solvent causes a spectral red shift. The calculated FTIR and geometry parameters are in good agreement with previous experimental data. Donor-acceptor interaction energies are evaluated due to the importance of the charge transfer in the complex formation. It is observed that the free electrons of oxygen atom interact with the antibonding orbitals of the iron. Finally, some correlations between the quantum chemical reactivity indices of the complexes and solvent polarity are considered. The study indicates a linear correlation between chemical hardness and binding energies of [Fe(cat)3]3﹣?complex.展开更多
基金supported by grants from the Zhejiang Provincial Natural Science Foundation(LGJ22H180001)Zhejiang Medical and Health Science and Technology Project(2021KY249)the National Key R&D Program of China(2017YFC1310000).
文摘Attempts have been made to modulate motor sequence learning(MSL)through repetitive transcranial magnetic stimulation,targeting different sites within the sensorimotor network.However,the target with the optimum modulatory effect on neural plasticity associated with MSL remains unclarified.This study was therefore designed to compare the role of the left primary motor cortex and the left supplementary motor area proper(SMAp)in modulating MSL across different complexity levels and for both hands,as well as the associated neuroplasticity by applying intermittent theta burst stimulation together with the electroencephalogram and concurrent transcranial magnetic stimulation.Our data demonstrated the role of SMAp stimulation in modulating neural communication to support MSL,which is achieved by facilitating regional activation and orchestrating neural coupling across distributed brain regions,particularly in interhemispheric connections.These findings may have important clinical implications,particularly for motor rehabilitation in populations such as post-stroke patients.
基金Supported by the Natural Science Foundation of Sichuan Province(2023NSFSC1172).
文摘The"Talk to the Plants"course,as an interdisciplinary integrated teaching innovation practice course,aims to break through the knowledge-imparting model of traditional botany education.It establishes a profound interactive bridge between humans and plants,cultivating students'ecological awareness,scientific literacy,and humanistic values.With life education at its core,the course integrates multidisciplinary knowledge from botany,ecology,psychology,and arts.Leveraging modern technologies including VR/AR and sensor monitoring,it creates immersive learning environments that guide students to engage with plants through scientific inquiry,emotional empathy,and artistic expression.This exploration establishes a new paradigm for developing well-rounded talents in ecological civilization while offering both theoretical insights and practical models for interdisciplinary curriculum reform in the new era,demonstrating significant value in educational innovation.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFA1407001)the Department of Science and Technology of Jiangsu Province(Grant No.BK20220032)+1 种基金support from the Guang Dong Basic and Applied Basic Research Foundation(Grant No.2023A1515010365)support from the Postgraduate Research and Practice Innovation Program of Jiangsu Province under Grant No.KYCX25_1934。
文摘Heat dissipation highly relies on the thermal conductivity(κ)of materials.Materials with large bandgaps and signifcant atomic mass ratios,such as BAs,SiC,andθ-TaN,have attracted considerable attention due to their potential for achieving ultra-highκ,with BAs serving as a particularly representative example due to its unique combination of large bandgap and high thermal conductivity.In this paper,the efects of atomic mass modifcation on phonon bandgap andκare systematically investigated using a BAs model,accounting for both three-and four-phonon scattering processes.A 20%increase inκcan be obtained by substituting B,achieved through widening the phonon bandgap,which suppresses phonon scattering.Notably,the AAOO four-phonon scattering channel is more suppressed than the AAO three-phonon channel,leading to an increased phonon lifetime(τ).For As,κcan also be enhanced by 5%when replaced by lighter atoms,such as^(69)As,primarily due to the increased phonon group velocity(υ).We systematically clarify how atomic-mass-induced bandgap variations afectτ,υ,and thereforeκin wide-bandgap systems.Our work provides a specifc scheme for further improving the ultra-highκof materials with large bandgaps,which possesses great guiding signifcance.
基金partly supported by grants from the Beijing Municipal Science and Technology Commission(No.Z221100007422008)。
文摘Objective:Allogeneic hematopoietic stem cell transplantation(allo-HSCT)is the only potentially curative method for treating myelodysplastic syndrome(MDS).Post-HSCT measurable residual disease(post-HSCT MRD)is associated with inferior transplant outcomes.In this prospective study,we aimed to investigate the prognostic value of post-HSCT MRD in relapse prediction in MDS.Methods:A total of 166 patients diagnosed with MDS were prospectively enrolled in this study.The KaplanMeier method was used to calculate the survival probabilities.Potential risk factors for outcomes after transplantation were evaluated through univariate and multivariate Cox regression models.Results:For patients with negative and positive post-HSCT MRD,the cumulative incidence of relapse(CIR)and disease-free survival(DFS)at 3 years were 5.9%and 69.6%(P<0.001)and 82.7%and 26.1%(P<0.001),respectively.In the multivariate analysis,post-HSCT MRD(HR=22.801,P<0.001)and Revised International Prognostic Scoring System(IPSS-R)risk stratification(HR=4.346,P=0.003)were independently correlated with relapse.A scoring system for relapse prediction was built based on post-HSCT MRD and IPSS-R stratification.The cumulative incidence of relapse at 3 years was 1.1%,15.8%,and 91.7%for patients with scores of 0,1,and 2,respectively(P<0.001).Conclusions:Our results demonstrated both post-HSCT MRD and IPSS-R scores were independent prognostic factors for OS,DFS,and relapse for MDS patients after allo-HSCT.The risk score system could better predict transplant outcomes and refine the risk stratification than alone in patients with MDS.
基金Project supported by the Hunan Provincial Natural Science Foundation(Grant Nos.2024JJ6190 and 2024JK2007-1)。
文摘Chemical short-range order(SRO),a phenomenon at the atomic scale resulting from inhomogeneities in the local chemical environment,is usually studied using machine learning force field-based molecular dynamics simulations due to the limitations of experimental methods.To promote the reliable application of machine potentials in high-entropy alloy simulations,first,this work uses NEP models trained on two different datasets to predict the SRO coefficients of NbMoTaW.The results show that within the same machine learning framework,there are significant differences in the prediction of SRO coefficients for the Nb-Nb atomic pair.Subsequently,this work predicts the SRO coefficients of NbMoTaW using the NEP model and the SNAP model,both of which are trained on the same dataset.The results reveal significant discrepancies in SRO predictions for like-element pairs(e.g.,Nb-Nb and W-W)between the two potentials,despite the identical training data.The findings of this study indicate that discrepancies in the prediction results of SRO coefficients can arise from either the same machine learning framework trained on different datasets or different learning frameworks trained on the same dataset.This reflects possible incompleteness in the current training set's coverage of local chemical environments at the atomic scale.Future research should establish unified evaluation standards to assess the capability of training sets to accurately describe complex atomic-scale behaviors such as SRO.
基金supported by the National Natural Science Foundation of China(52350410465)the General Projects of Guangdong Natural Science Research Projects(2023A1515011520).
文摘Accurate daily suspended sediment load(SSL)prediction is essential for sustainable water resource management,sediment control,and environmental planning.However,SSL prediction is highly complex due to its nonlinear and dynamic nature,making traditional empirical models inadequate.This study proposes a novel hybrid approach,integrating the Adaptive Neuro-Fuzzy Inference System(ANFIS)with the Gradient-Based Optimizer(GBO),to enhance SSL forecasting accuracy.The research compares the performance of ANFIS-GBO with three alternative models:standard ANFIS,ANFIS with Particle Swarm Optimization(ANFIS-PSO),and ANFIS with Grey Wolf Optimization(ANFIS-GWO).Historical SSL and streamflow data from the Bailong River Basin,China,are used to train and validate the models.The input selection process is optimized using the Multivariate Adaptive Regression Splines(MARS)method.Model performance is evaluated using statistical metrics such as Root Mean Square Error(RMSE),Mean Absolute Error(MAE),Mean Absolute Percentage Error(MAPE),Nash Sutcliffe Efficiency(NSE),and Determination Coefficient(R^(2)).Additionally,visual assessments,including scatter plots,Taylor diagrams,and violin plots,provide further insights into model reliability.The results indicate that including historical SSL data improves predictive accuracy,with ANFIS-GBO outperforming the other models.ANFIS-GBO achieves the lowest RMSE and MAE and the highest NSE and R^(2),demonstrating its superior learning ability and adaptability.The findings highlight the effectiveness of nature-inspired optimization algorithms in enhancing sediment load forecasting and contribute to the advancement of AI-based hydrological modeling.Future research should explore the integration of additional environmental and climatic variables to enhance predictive capabilities further.
文摘The increasing global adoption of electric vehicles(EVs)has led to a growing demand for a cost-effective and reliable charging infrastructure.This study presents a novel data-driven approach to assessing EV station performance by analyzing power consumption efficiency,station utilization rates,no-power session occurrences,and CO_(2)reduction metrics.A dataset of 17,500 charging sessions from 305 stations across a regional network was analyzed to identify operational inefficiencies and opportunities for infrastructure optimization.Results indicate a strong correlation between station utilization and energy efficiency,highlighting the importance of strategic station placement.The findings also emphasize the impact of no-power sessions on network inefficiency and the need for real-time station monitoring.CO_(2)reduction analysis demonstrates that optimizing EV charging performance can significantly contribute to sustainability goals.Based on these insights,this study recommends the implementation of predictive maintenance strategies,real-time user notifications,and diversified provider networks to improve station availability and efficiency.The proposed data-driven framework offers actionable solutions for policymakers,charging network operators,and urban planners to enhance EV infrastructure reliability and sustainability.
基金the National Natural Science Foundation of China(Nos.62374029,22175029,62474033,and W2433038)the Young Elite Scientists Sponsorship Program by CAST(No.YESS20220550)+2 种基金the Sichuan Science and Technology Program(No.2024NSFSC0250)the Natural Science Foundation of Shenzhen Innovation Committee(JCYJ20210324135614040)the Fundamental Research Funds for the Central Universities of China(No.ZYGX2022J032).
文摘Perovskite solar cells(PSCs)have emerged as promising photovoltaic technologies owing to their remarkable power conversion efficiency(PCE).However,heat accumulation under continuous illumination remains a critical bottleneck,severely affecting device stability and long-term operational performance.Herein,we present a multifunctional strategy by incorporating highly thermally conductive Ti_(3)C_(2)T_(X) MXene nanosheets into the perovskite layer to simultaneously enhance thermal management and optoelectronic properties.The Ti_(3)C_(2)T_(X) nanosheets,embedded at perovskite grain boundaries,construct efficient thermal conduction pathways,significantly improving the thermal conductivity and diffusivity of the film.This leads to a notable reduction in the device’s steady-state operating temperature from 42.96 to 39.97 under 100 mW cm^(−2) illumination,thereby alleviating heat-induced performance degradation.Beyond thermal regulation,Ti_(3)C_(2)T_(X),with high conductivity and negatively charged surface terminations,also serves as an effective defect passivation agent,reducing trap-assisted recombination,while simultaneously facilitating charge extraction and transport by optimizing interfacial energy alignment.As a result,the Ti_(3)C_(2)T_(X)-modified PSC achieve a champion PCE of 25.13%and exhibit outstanding thermal stability,retaining 80%of the initial PCE after 500 h of thermal aging at 85 and 30±5%relative humidity.(In contrast,control PSC retain only 58%after 200 h.)Moreover,under continuous maximum power point tracking in N2 atmosphere,Ti_(3)C_(2)T_(X)-modified PSC retained 70%of the initial PCE after 500 h,whereas the control PSC drop sharply to 20%.These findings highlight the synergistic role of Ti_(3)C_(2)T_(X) in thermal management and optoelectronic performance,paving the way for the development of high-efficiency and heat-resistant perovskite photovoltaics.
基金supported by the National Basic Research Program of China(973 Program)(Nos.2012CB619102 and 2012CB619100)the Research Fund for the Doctoral Program of Higher Education(No.20100001110011)+2 种基金the National Science Fund for Distinguished Young Scholars(No.51225101)the National Natural Science Foundation of China(No.31170909)the Guangdong Innovative Research Team Program(No. 201001C0104669453)
文摘Five pure metals including Fe, Mn, Mg, Zn and W have been investigated on their corrosion behavior and in vitro biocompatibility by electrochemical measurement, static immersion test, contact angle measurement, cytotoxicity and hemocompatibility tests. It is found that the sequence of corrosion rate of five metals in Hank's solution from high to low is: Mg 〉 Fe 〉 Zn 〉 Mn 〉 W. Fe, Mg and W show no cytotoxicity to L929 and ECV304 cells, Mn induces significant cytotoxicity to both L929 and ECV304 cells, and Zn has almost no inhibition effect on the metabolic activities of ECV304 while largely reduces the cell viability of L929 cells. The hemolysis percentage of five pure metals is lower than 5% except for Mg and platelets adhered on Zn has been activated and pseudopodia-like structures can be observed while platelets on the other four metals keep normal.
基金supported by the National Basic Research Program of China(973 Program)(Grant Nos.2012CB619102 and 2012CB619103)the State Key Laboratory for Mechanical Behavior of Materials(Grant No.20111210)+3 种基金the National High Technology Research and Development Program of China(863 Program)(Grant No.2011AA030103)the Research Fund for the Doctoral Program of Higher Education(Grant No. 20100001110011)the National Natural Science Foundation of China(No.31170909)the National Science Fund for Distinguished Young Scholars(Grant No.51225101)
文摘AZ31 magnesium alloy fibers reinforced poly(lactic-co-glycolic acid) (PLGA) composites were prepared and their mechanical property, immersion corrosion behavior and biocompatibility were studied. The tensile test showed that with the addition of AZ31 fibers, the composites had a significant increment in tensile strength and elongation. For the direct cell attachment test, all the cells showed a healthy morphology and spread well on the experimental sample surfaces. The immersion results indicated that pH values of the immersion medium increased with increasing AZ31 fiber contents. All the in vitro experimental results indicated that this new kind of magnesium alloy fibers reinforced PLGA composites show a potential for future biomedical applications.
基金the financial support of the National Basic Research Program of China(Grant No.2012CB619102)National High Technology Research and Development Program of China(Grant No.2011AA030103)+1 种基金National Science and Technology Support Program(Grant No.2012BAI18B01)Guangdong Innovation R&D Team Project(Grant No. 201001C0104669453)
文摘The mechanical properties, chemical properties and biocompatibility of Mg-3Sn-0.5Mn alloy were tested. A series of in vitro evaluations such as tensile test, static and dynamic immersion test, hemocompatibility test as well as cytotoxicity test were presented, with commercial magnesium alloy WE43 as the control. Mg-3Sn-0.5Mn alloy possesses suitable strength and superior ductility compared with WE43 and AZ31. Static immersion and dynamic degradation tests showed more uniform degradation with a more moderate rate for Mg-3Sn-0.5Mn alloy (0.34 mm/y in static condition and 0.25 mm/y in dynamic condition) compared with WE43 alloy (0.42 mm/y in static condition and 0.33 mm/y in dynamic condition) in Hank's solution. Blood compatibility evaluation suggested that Mg-3Sn-0.5Mn alloy had no destructive effect on erythrocyte and showed excellent anti-thrombogenicity to blood system. Besides, Mg-3Sn-0.5Mn alloy showed no inhibition effect to L929 metabolic activity and mild toxicity to vascular smooth muscle cell (VSMC) in preliminary cell viability assessment. By considering its excellent mechanical strength, corrosion resistance, low ion release rate and good biocompatibility, Mg-3Sn-0.5Mn alloy may be a promising economical candidate as biomedical implant material for load-bearing clinical applications in the future.
基金partially supported by the National Natural Science Foundation of China(Grant Nos. 11890710, 11890714, and 12147101)the BMBF funded KISS consortium (Grant No. 05D23RI1) in the ErUM-Data action plan。
文摘In recent years, machine learning(ML) techniques have emerged as powerful tools for studying many-body complex systems, and encompassing phase transitions in various domains of physics. This mini review provides a concise yet comprehensive examination of the advancements achieved in applying ML to investigate phase transitions, with a primary focus on those involved in nuclear matter studies.
文摘An algorithm named InterOpt for optimizing operational parameters is proposed based on interpretable machine learning,and is demonstrated via optimization of shale gas development.InterOpt consists of three parts:a neural network is used to construct an emulator of the actual drilling and hydraulic fracturing process in the vector space(i.e.,virtual environment);:the Sharpley value method in inter-pretable machine learning is applied to analyzing the impact of geological and operational parameters in each well(i.e.,single well feature impact analysis):and ensemble randomized maximum likelihood(EnRML)is conducted to optimize the operational parameters to comprehensively improve the efficiency of shale gas development and reduce the average cost.In the experiment,InterOpt provides different drilling and fracturing plans for each well according to its specific geological conditions,and finally achieves an average cost reduction of 9.7%for a case study with 104 wells.
基金National Natural Science Foundation of China (Grant No. 82003953)China Postdoctoral Science Foundation (Grant No. 2019M662278)+2 种基金Science and Technology Project of Education Department of Jiangxi Province (Grant No. GJJ190688, GJJ201252)Po stdoctoral Science Foundation of Jiangxi Province (Grant No. 2019KY42)Key Scientific Research Foundation of Jiangxi University of Traditional Chinese Medicine (Grant No. 2004/538200010402)。
文摘The encapsulation of essential oil components in cyclodextrins(CDs)to form inclusion complexes(ICs)is an effective strategy for improving their stability and bioaccessibility.The aim of the present study was to obtain a deeper understanding of the encapsulation behavior of multi-components inβ-CD.vip molecules ofα-pinene,myrcene,and 3-carene,having the same molecular weight,formed ICs withβ-CD by a freeze-drying method.A simplex lattice mixture design with 28 experiments was carried out.Statistical analysis was applied to analyze the encapsulation behavior of vip components,and quantitative models of vip components in ICs were constructed by coupling with near-infrared(NIR)spectroscopy and chemometrics analysis.Besides,the molecular docking technique was used to obtain the optimal conformation and explain the binding behavior of inclusion.The results suggested that the spatial structure and ratio of vip molecules were the key factors affecting the encapsulation effect.A non-destructive and rapid NIR analytical model for the vip component in ICs could be obtained by second derivative(2nd der)pretreatment.Collectively,the encapsulation of vip components inβ-CD was differentiated,and NIR could be used as a rapid and non-destructive tool for quantitative analysis of ICs.
文摘One of the major problems of modern neurobiology is how to replace dead or damaged neurons in the human brain or spinal cord after injury or as a consequence of neurodegenerative dis- eases. In fact, because adult mammalian neurons are post-mi- totic cells that cannot divide to replace dead cells, loss due to lesion or disease is permanent. Furthermore, surviving neurons have modest capacity to regenerate their damaged axons and re-establish functional connections. Thus, a gradual neurode- generative scenario with certain similarities in stroke, brain or spinal cord injuries and neurological diseases like Alzheimer's disease is produced. These conditions represent the major disease burden of the modern world in terms of mortality, dis- ability, productivity loss and health-care costs (World Health Organization, 2008). While much effort has been directed to understand the molecular and cellular mechanisms involved in the pathology of these diseases to set new effective treatments, many neuroprotective and regenerative approaches, although showing positive results in preclinical studies, have so far failed to provide strong benefit to patients.
基金supported by the National Social Science Fund of China for Lesser-Known Traditional Knowledge冷门绝学(Group Project)“Research on the Method to Calculate the Five Planets in Chinese Calendrical Systems”中国古代历法中的“步五星术”研究(20VJXT005)。
文摘The planetary theory in the Great Expansion System(Dayan li大衍历,727 CE)is investigated,with a detailed example of Mars.In ancient Chinese astrology,the position of one planet and the relative positions of different planets had important astrological significance.Thus,planetary theory is an important part of Chinese mathematical astronomy.The Great Expansion System,which was compiled by Yixing一行of the Tang唐dynasty(618–907 CE),provided many innovations in planetary theory.Based on the extant Treatises on Mathematical Harmonics and Astronomy(Lüli zhi律历志)in Chinese official histories,the Great Expansion System was the first Chinese astronomical system to include tables of the planetary equation of center and procedures for correcting the influence of the planetary equation of center on the position of a planet.It was also the first Chinese system to design a table of the planetary phases of motion for calculating the mean position of a planet,which was the basis for calculating the true position of the planet.In addition,Yixing proposed the concept of the precession of planetary perihelion and gave the values of the precession of planetary perihelion for the first time in ancient China.The innovations of the Great Expansion System regarding planetary theory established its important position in the history of Chinese astronomical systems.Mars is taken as a case study to investigate the planetary theory in the Great Expansion System,including the astronomical constants related to Mars,two important astronomical tables,namely the table of the equation of center and the table of the phase motion of Mars in one synodic period,and the procedures for calculating the position of Mars on any given day using the planetary and solar equations of center.Two questions are addressed.First,how did Yixing correct the influence of the equation of center of Mars on the time of mean conjunction and the mean position of Mars?Second,how did Yixing calculate the true position of Mars on any given day?The original text of the Great Expansion System is analyzed to show how Yixing developed the planetary theory in the Sui and early Tang periods and constructed a complete method for predicting the true positions of planets using the planetary and solar equations of center.
基金supported by the National Basic Research Program (Grant No2007CB935602)the National Natural Science Foundation of China (Grant Nos90607004,10672005 and 10872008)
文摘Quantitative investigation on mechanical characteristics of cardiac myocytes has important physiological significance. Based on elastic substrate technique, this paper develops a set of algorithms for high-efficiency cellular traction recovery. By applying a gradient-based digital image correlation method to track randomly distributed fluorescence microbeads on the deformed substrate induced by single cardiac myocyte, high-resolution substrate displacement field can readily be obtained. By using a numerical algorithm based on the integral Boussinesq solution, cell-substrate tractions are reconstructed in a stable and reliable manner. Finally, spatiotemporal dynamics of a single cardiac myocyte is investigated as it adheres to a polyacrylamide elastic substrate.
基金Supported by the Free Exploration Subject of State Key Laboratory of Environmental Criteria and Risk Assessment,CRAES(No.2005001002)
文摘We investigated the bacterioplankton abundance, community composition and the associated Vibrio clades of natural seawater in Bohai Sea coastal waters. Seawater samples (10 L in triplicate) were collected at 0.5, 3, and 5 m depths near the coastal aquaculture zone of the Bohai Sea on May 12, 2016. Real-time PCR and 16S rRNA gene amplicon high-throughput sequencing methods were employed by which 485 operational taxonomic units (OTUs) at a 97% sequence similarity level were generated. Gammaproteobacteria, Alphaproteobacteria, and Bacteroidetes were the most abundant groups, accounting for 49.5%, 23.5%, and 18.9% of the total assemblage, respectively. Obvious variations in Pseudoalteromonas, Vibrio, and Octadecabacter , which were the most abundant genera, could be observed among diff erent samples. Notably, the results of Vibrio -specifi c real-time PCR indicated that Vibrio had extremely high 16S rRNA gene copy numbers. The 16S rRNA gene sequencing results across all the samples also indicated that they occupied a large proportion of the total assemblage. Both the alpha diversity and major bacterioplankton group Pseudoalteromonas had significant correlations with the concentration of PO4^3-. Overall, studies on bacterioplankton communities with highly abundant Vibrio clades can provide interesting insight into the microbial function and health assessment of the Bohai Sea coastal ecosystem.
基金financially supported by National Natural Science Foundation of China(No.91860131 and No.52074157)National Key Research and Development Program of China(No.2017YFB0702901)+1 种基金Shenzhen Science and Technology Innovation Commission under the Projects(No.JCYJ20170817111811303,No.KQTD20170328154443162 and ZDSYS201703031748354)joint Ph.D.program between SUSTech and UoB(No.FEFE/GAS1792)。
文摘Inconel 738 LC samples were fabricated using laser powder bed fusion under continuous-wave and pulsed-wave modes.Microstructure,surface quality and mechanical properties were compared to evaluate the printing quality between these 2 laser beam modes.The results show that the application of pulsed wave could effectively eliminate cracking in the as-fabricated sample,despite 0.046%porosity generated.Further microstructure analysis revealed that the refinement of grains by the pulsed-wave laser beam was the main contributor in eliminating the cracks.And this refinement was ascribed to the higher cooling rate under the discontinuous radiation of laser beam proofed by the numerical simulation.And the pore formation was related to Rayleigh instability and residual bubbles in the sample under the pulsed-wave mode,while pores were less detrimental to the mechanical properties than cracks.Therefore,the part under the pulsed-wave mode exhibited superior mechanical performance compared to that under the continuous-wave mode.
文摘In this study, in order to explain the solvent and spin state effects on the molecular structure of catechol-Fe complex [Fe(cat)3]n﹣?where n = 2 and 3, Hartree Fock (HF)-Density Functional Theory (DFT) hybrid calculations are performed at the B3LYP/6-311g(d,p) level of theory. The binding energies of Fe2+ and Fe3+ in high-spin state are higher than intermediate and low-spin states which show that the complex formation in a high spin state is more favorable. The calculated binding energies at different solvents indicate that the binding energies in polar solvents are lower than non-polar solvents. Furthermore, spectroscopic studies including FTIR and Raman spectrum in various solvents reveal that the formation of intermolecular bonds between the oxygen atom of carbonyl group and the hydrogen atom of solvent causes a spectral red shift. The calculated FTIR and geometry parameters are in good agreement with previous experimental data. Donor-acceptor interaction energies are evaluated due to the importance of the charge transfer in the complex formation. It is observed that the free electrons of oxygen atom interact with the antibonding orbitals of the iron. Finally, some correlations between the quantum chemical reactivity indices of the complexes and solvent polarity are considered. The study indicates a linear correlation between chemical hardness and binding energies of [Fe(cat)3]3﹣?complex.