In this study,the potential application of shaped charge jets as transient antennas for electromagnetic signal transmission was explored and an electromagnetic pulse radiation system with a shaped charge jet as a tran...In this study,the potential application of shaped charge jets as transient antennas for electromagnetic signal transmission was explored and an electromagnetic pulse radiation system with a shaped charge jet as a transient antenna was proposed.During the research,crucial characteristics of the transient antenna formed by a shaped charge with a 30 mm diameter,such as resonant frequency,radiation pattern,and radiation efficiency,were evaluated.The typical shaped charge jet morphology was obtained based on the simulations,in which it could insight the dynamic behavior of the shaped charge jet selected.An equivalent model experiment was employed to test the radiation efficiency,and it showed that a shorting pin loading method could increase the relative bandwidth of the jet antenna to 32.8%,and the experimental results correlate with the theoretical predictions for half-wave dipole antennas reasonably well.Additionally,variations in the diameter of the shaped charge jet were found to affect the input impedance and impedance bandwidth,while the length of the jet influenced the resonant frequency of the antenna.This suggests that altering these parameters can achieve reconfigurability of the jet antenna.展开更多
The redshifted 21 cm line,arising from neutral hydrogen,offers a unique probe into the intergalactic medium and the first stars and galaxies formed in the early universe.However,detecting this signal is a challenging ...The redshifted 21 cm line,arising from neutral hydrogen,offers a unique probe into the intergalactic medium and the first stars and galaxies formed in the early universe.However,detecting this signal is a challenging task because of artificial radio-frequency interference(RFI)and systematic errors such as ground effects.The interior of the Antarctic continent provides an excellent location to make such observations,with minimal RFI and relatively stable foreground signals.Moreover,a flat plateau in central Antarctica,with an ice cap over 2000 m deep,will show less ground reflection of radio waves,reducing the signal complexity in the area around the probing antenna.It may be advantageous to perform cosmological 21 cm experiments in Antarctica,and a 21 cm Antarctic global spectrum experiment can potentially be deployed on the Antarctic ice cap.We have performed preliminary instrumental design,system calibration,and implementation of such an instrument optimized for extreme cold and capable of long-term autonomous operation.This system shows the ability to effectively detect the 21 cm signal,confirming Antarctica as an excellent observational site for radio cosmology.展开更多
Facial paralysis comorbidities is now understood to include two distinct forms:synkinesis and micro-entrapment syndrome of nerves innervating the face(MESNIF).These disorders manifest as oromandibular synkinesis,stiff...Facial paralysis comorbidities is now understood to include two distinct forms:synkinesis and micro-entrapment syndrome of nerves innervating the face(MESNIF).These disorders manifest as oromandibular synkinesis,stiffness and atrophy of facial muscles on one side,which affect activities of daily living.Acupoint Injection is a treatment for facial paralysis,combining the meridian theory of traditional Chinese medicine,with the injection of specific drugs into acupuncture points of the face.In recent years,the use of acupoint injections has shown in remarkable clinical efficacy and few adverse effects.We report the case to introduce this integrative therapy and outline the key principles of rehabilitation therapy.展开更多
Though the lithium-ion battery is universally applied,the reliability of lithium-ion batteries remains a challenge due to various physicochemical reactions,electrode material degradation,and even thermal runaway.Accur...Though the lithium-ion battery is universally applied,the reliability of lithium-ion batteries remains a challenge due to various physicochemical reactions,electrode material degradation,and even thermal runaway.Accurate estimation and prediction of battery health conditions are crucial for battery safety management.In this paper,an end-cloud collaboration method is proposed to approach the track of battery degradation process,integrating end-side empirical model with cloud-side data-driven model.Based on ensemble learning methods,the data-driven model is constructed by three base models to obtain cloud-side highly accurate results.The double exponential decay model is utilized as an empirical model to output highly real-time prediction results.With Kalman filter,the prediction results of end-side empirical model can be periodically updated by highly accurate results of cloud-side data-driven model to obtain highly accurate and real-time results.Subsequently,the whole framework can give an accurate prediction and tracking of battery degradation,with the mean absolute error maintained below 2%.And the execution time on the end side can reach 261μs.The proposed end-cloud collaboration method has the potential to approach highly accurate and highly real-time estimation for battery health conditions during battery full life cycle in architecture of cyber hierarchy and interactional network.展开更多
In this paper,we systematically investigated the microstructure evolution and coercivity mechanism of hydrogenation-disproportionation-desorption-recombination(HDDR)treated Nd-Fe-B strip cast alloys by transmission el...In this paper,we systematically investigated the microstructure evolution and coercivity mechanism of hydrogenation-disproportionation-desorption-recombination(HDDR)treated Nd-Fe-B strip cast alloys by transmission electron microscopy(TEM)and three-dimensional atom probe(3 DAP)analyses.The rodlike NdH_(2+x) phases with diameters of 10-20 nm are embedded intoα-Fe matrix,which hereditarily leads to textured grains in HDDR alloy.The migration of NdH_(2+x) from Nd-rich region toα-Fe matrix during hydrogen absorption process contributes to the uniform redistribution of Nd-rich phases after HDDR treatment The HDDR alloy with single domain grain sizes of 200-300 nm exhibits relatively low coercivity of 1.01 T that arises from pinning magnetic domain motion.The weak c-axis orientation of HDDR alloy results in a lower reverse magnetic field(coercivity)to reduce remanence to 0.Moreover,the direct contact of Nd_(2)Fe_(14)B grains and the high concentration of ferromagnetic elements(Fe content≈66.06 at%,Co content≈0.91 at%)in Nd-rich grain boundary layer lead to strong magnetostatic coupling effect among Nd_(2) Fe_(14)B grains.The nano-sized a-Fe inside Nd_(2) Fe_(14)B matrix makes the magnetization reversal easily and decreases the coercivity of HDDR alloy.展开更多
The use of a shaped liner driven by electromagnetic force is a new means of forming jets. To study the mechanism of jet formation driven by electromagnetic force, we considered the current skin effect and the characte...The use of a shaped liner driven by electromagnetic force is a new means of forming jets. To study the mechanism of jet formation driven by electromagnetic force, we considered the current skin effect and the characteristics of electromagnetic loading and established a coupling model of "ElectriceMagnetic eForce" and the theoretical model of jet formation under electromagnetic force. The jet formation and penetration of conical and trumpet liners have been calculated. Then, a numerical simulation of liner collapse under electromagnetic force, jet generation, and the stretching motion were performed using an ANSYS multiphysics processor. The calculated jet velocity, jet shape, and depth of penetration were consistent with the experimental results, with a relative error of less than 10%. In addition, we calculated the jet formation of different curvature trumpet liners driven by the same loading condition and obtained the influence rule of the curvature of the liner on jet formation. Results show that the theoretical model and the ANSYS multiphysics numerical method can effectively calculate the jet formation of liners driven by electromagnetic force, and in a certain range, the greater the curvature of the liner is, the greater the jet velocity is.展开更多
The large-scale application of lithium metal batteries remains a challenge due to the hydrolysis of LiPF_(6),which can induce capacity fade and series of safety issues.Prof.Ma and his co-workers have designed a hydrop...The large-scale application of lithium metal batteries remains a challenge due to the hydrolysis of LiPF_(6),which can induce capacity fade and series of safety issues.Prof.Ma and his co-workers have designed a hydrophobic Li^(+)-solvated structure to obtain high performances lithium metal batteries.The specific functional groups of theadditive,hexafluoroisopropyl acrylate.展开更多
The Solar Upper Transition Region Imager(SUTRI)focuses on the solar transition region to achieve dynamic imaging observation of the upper transition region.In this paper,we report the optical system design,mechanical ...The Solar Upper Transition Region Imager(SUTRI)focuses on the solar transition region to achieve dynamic imaging observation of the upper transition region.In this paper,we report the optical system design,mechanical design,ultrasmooth mirror manufacture and measurement,EUV multilayer film coating,prelaunch installation and calibration for the SUTRI payload at IPOE,Tongji University.Finally,the SUTRI carried by the SATech-01 satellite was successfully set to launch.All functions of this telescope were normal,and the observation results obtained in orbit were consistent with the design.展开更多
As the lithium-ion battery is widely applied,the reliability of the battery has become a high-profile content in recent years.Accurate estimation and prediction of state of health(SOH)and remaining useful life(RUL)pre...As the lithium-ion battery is widely applied,the reliability of the battery has become a high-profile content in recent years.Accurate estimation and prediction of state of health(SOH)and remaining useful life(RUL)prediction are crucial for battery management systems.In this paper,the core contribution is the construction of a datadriven model with the long short-term memory(LSTM)network applicable to the time-series regression prediction problem with the integration of two methods,data-driven methods and feature signal analysis.The input features of model are extracted from differential thermal voltammetry(DTV)curves,which could characterize the battery degradation characteristics,so that the accurate prediction of battery capacity fade could be accomplished.Firstly,the DTV curve is smoothed by the Savitzky-Golay filter,and six alternate features are selected based on the connection between DTV curves and battery degradation characteristics.Then,a correlation analysis method is used to further filter the input features and three features that are highly associated with capacity fade are selected as input into the data driven model.The LSTM neural network is trained by using the root mean square propagation(RMSprop)technique and the dropout technique.Finally,the data of four batteries with different health levels are deployed for model construction,verification and comparison.The results show that the proposed method has high accuracy in SOH and RUL prediction and the capacity rebound phenomenon can be accurately estimated.This method can greatly reduce the cost and complexity,and increase the practicability,which provides the basis and guidance for battery data collection and the application of cloud technology and digital twin.展开更多
The influence of a magnetic field on the stability of a shaped charge jet is experimentally investigated at standoffs of 490,650 and 800 mm.The experimental results without and with the magnetic field are compared in ...The influence of a magnetic field on the stability of a shaped charge jet is experimentally investigated at standoffs of 490,650 and 800 mm.The experimental results without and with the magnetic field are compared in terms of the shaped charge jet form,stability and penetration ability.A theoretical model based on one-dimension fluid dynamics is then developed to assess the depth of penetration of the shaped charge at those three standoffs and magnetic conditions.The results show that the penetration capability can be enhanced in more than 70%by the magnetic field.The theoretical calculations are compared with the experimental results with reasonably good correlation.In addition,the parameters introduced in the theory are discussed together with the experiments at three standoffs studied.展开更多
In recent years, immunotherapy has been gradually established as the fourth frequently adopted antitumor therapy, following surgery, chemotherapy and radiotherapy, for advanced urologic malignancies with an improved u...In recent years, immunotherapy has been gradually established as the fourth frequently adopted antitumor therapy, following surgery, chemotherapy and radiotherapy, for advanced urologic malignancies with an improved understanding of theoretical basis, such as molecular biology and immunology. Thereinto, adoptive cellular immunotherapy （ACI） has become one of the hotspots, which comprises a variety of treatment approaches, such as TIL, CIK cell, ~＇~ T cell, CAR-engineered T cell and Allogeneie stem cell transplantation （alloSCT）. Although preclinical efficacy has been demonstrated remarkably, clinical trials could not consistently show the benefit due to multi-factors in complex immnnosuppressive microenvironment in vivo compared to that of in vitro. Here we review some timely aspects of ACI for advanced urologic malignancies, and describe the current status and limitation of immunotherapy from the cellular level. It＇s our expectation to provide prompting consideration of novel combinatorial ACI strategies and a resurgence of interest in ACI for advanced urologic malignancies.展开更多
The bidding strategies of power suppliers to maximize their interests is of great importance.The proposed bilevel optimization model with coalitions of power suppliers takes restraint factors into consideration,such a...The bidding strategies of power suppliers to maximize their interests is of great importance.The proposed bilevel optimization model with coalitions of power suppliers takes restraint factors into consideration,such as operating cost reduction,potential cooperation,other competitors’bidding behavior,and network constraints.The upper model describes the coalition relationship between suppliers,and the lower model represents the independent system operator’s optimization without network loss(WNL)or considering network loss(CNL).Then,a novel algorithm,the evolutionary game theory algorithm(EGA)based on a hybrid particle swarm optimization and improved firefly algorithm(HPSOIFA),is proposed to solve the bi-level optimization model.The bidding behavior of the power suppliers in equilibrium with a dynamic power market is encoded as one species,with the EGA automatically predicting a plausible adaptation process for the others.Individual behavior changes are employed by the HPSOIFA to enhance the ability of global exploration and local exploitation.A novel improved firefly algorithm(IFA)is combined with a chaotic sequence theory to escape from the local optimum.In addition,the Shapley value is applied to the profit distribution of power suppliers’cooperation.The simulation,adopting the standard IEEE-30 bus system,demonstrates the effectiveness of the proposed method for solving the bi-level optimization problem.展开更多
Objective:We carried out a meta-analysis to assess the effectiveness and safety of radiotherapy combined with surgery for gastric cancer.Methods:Randomized Clinical Trials (RCTs) in which radiotherapy (preoperative,in...Objective:We carried out a meta-analysis to assess the effectiveness and safety of radiotherapy combined with surgery for gastric cancer.Methods:Randomized Clinical Trials (RCTs) in which radiotherapy (preoperative,intraoperative and postoperative),was compared with surgery alone in resectable gastric cancer were identified by searching Cochrane Library (Issue 2,2009),PubMed (Jan 1966-Jun 2009),EMBASE (Jan 1974-Jun 2009),Chinese Biomedical Literature Database (Jan 1978-Jun 2009),Chinese Science and Technology Periodicals Database (Jan 1989-Jun 2009),China National Knowledge Infrastructure (Jan 1994-Jun 2009) and Wanfang database (Jan 1997-Jun 2009) in English and Chinese languang.Two researchers assessed the quality of included randomized controlled trials (RCT) extracted data independently.The RevMan 5.0 software was used for meta-analysis.Our researchers assessed the quality of included randomized controlled trials (RCT) extracted data independently.The RevMan 5.0 software was used for meta-analysis.Results:Nine randomized controlled trials of 1 548 patients were selected for meta-analysis.Five randomized controlled trials were related with comparison of preoperative radiotherapy plus surgery with single surgery.Two randomized controlled trials were the comparative studies between surgery plus postoperative and single surgery.The meta-analysis results showed that:(1) compared with surgery alone,preoperative radiotherapy combined with surgery can increase 3 years (OR=1.78;95% CI 1.14-2.78,P=0.01),5 years (OR=1.67;95% CI 1.22-2.29,P=0.001),10 years (OR=1.64;95% CI 1.03-2.60,P=0.04) survival rate and resection rate (OR=2.15;95% CI 1.31-3.54,P=0.003);reduce the of tumor recurrence rate (OR=0.59;95% CI 0.37-0.92,P=0.02) and metastasis rate (OR=0.44;95% CI 0.27-0.73,P=0.001);(2) The tumor recurrent rates (OR=0.19,95% CI 0.03-1.14,P=0.07) and tumor metastasis rate (OR=0.09;95% CI 0.00-1.77,P=0.11) had no difference between single surgery group and peri-operative radiotherapy plus surgery group;(3) Postoperative radiotherapy compared with surgery alone had no significant effects on 1 year (OR=0.83;95% CI 0.60-1.15,P=0.26) and 3 years (OR=0.75;95% CI 0.51-1.11,P=0.15) survival rate compared with single surgery,but the 5-year survival rates (OR=0.57;95% CI 0.34-0.95,P=0.03) of the patients who received surgery alone was higher than those who received combined therapy.No difference of the tumor recurrence rate (OR=0.59;95% CI 0.33-1.05,P=0.07),tumor metestasis rate (OR=0.90;95% CI 0.51-1.59,P=0.71) and anastomotic leak (OR=0.98;95% CI 0.25-3.65,P=0.98) were observed between the two groups.Conclusion:Preoperative radiotherapy combined surgery is more rational and effective than surgery alone of gastric cancer.However,in terms of the clinical effects of perioperarive or postoperative radoiotherapy combined with surgery,much multicenter,largescale,high-quality,double-blind and rigorously designed studies would be needed than currently available in the future.展开更多
To develop emerging electrode materials and improve the performances of batteries,the machine learning techniques can provide insights to discover,design and develop battery new materials in high-throughput way.In thi...To develop emerging electrode materials and improve the performances of batteries,the machine learning techniques can provide insights to discover,design and develop battery new materials in high-throughput way.In this paper,two deep learning models are developed and trained with two feature groups extracted from the Materials Project datasets to predict the battery electrochemical performances including average voltage,specific capacity and specific energy.The deep learning models are trained with the multilayer perceptron as the core.The Bayesian optimization and Monte Carlo methods are applied to improve the prediction accuracy of models.Based on 10 types of ion batteries,the correlation coefficients are maintained above 0.9 compared to DFT calculation results and the mean absolute error of the prediction results for voltages of two models can reach 0.41 V and 0.20 V,respectively.The electrochemical performance prediction times for the two trained models on thousands of batteries are only 72.9 ms and 75.7 ms.Besides,the two deep learning models are applied to approach the screening of emerging electrode materials for sodium-ion and potassium-ion batteries.This work can contribute to a high-throughput computational method to accelerate the rational and fast materials discovery and design.展开更多
The exchange-coupled [Co/Ni]N/Tb Fe nano-magnetic films can display strong perpendicular magnetic anisotropy(PMA) which depends on the Tb:Fe component ratio, Tb Fe layer thickness and the repetition number N of [Co/Ni...The exchange-coupled [Co/Ni]N/Tb Fe nano-magnetic films can display strong perpendicular magnetic anisotropy(PMA) which depends on the Tb:Fe component ratio, Tb Fe layer thickness and the repetition number N of [Co/Ni]Nmultilayer. Perpendicular spin valves in the nano thickness scale, consisting of a [Co/Ni]3free and a [Co/Ni]5/Tb Fe reference multilayer, show high giant magnetoresistance(GMR) signal of 6.5 % and a large switching field difference over3 k Oe. However, unexpected slanting of the free layer magnetization, accompanied by a reduced GMR ratio, was found to be caused by the presence of a thick Fe-rich or even a thin but Tb-rich Tb Fe layer. We attribute this phenomenon to the large magnetostriction effect of Tb Fe which probably induces strong stress acting on the free layer and hence reduces its interfacial PMA.展开更多
This paper presents an algorithm to solve the problem of Photo-Response Non-Uniformity(PRNU)noise facing stabilized video.The stabilized video undergoes in-camera processing like rolling shutter correction.Thus,misali...This paper presents an algorithm to solve the problem of Photo-Response Non-Uniformity(PRNU)noise facing stabilized video.The stabilized video undergoes in-camera processing like rolling shutter correction.Thus,misalignment exists between the PRNU noises in the adjacent frames owing to the global and local frame registration performed by the in-camera processing.The misalignment makes the reference PRNU noise and the test PRNU noise unable to extract and match accurately.We design a computing method of maximum likelihood estimation algorithm for extracting the PRNU noise from stabilized video frames.Besides,unlike most prior arts tending to match the PRNU noise in whole frame,we propose a new patch-based matching strategy,aiming at reducing the influence from misalignment of frame the PRNU noise.After extracting the reference PRNU noise and the test PRNU noise,this paper adopts the reference and the test PRNU overlapping patch-based matching.It is different from the traditional matching method.This paper conducts different experiments on 224 stabilized videos taken by 13 smartphones in the VISION database.The area under curve of the algorithm proposed in this paper is 0.841,which is significantly higher than 0.805 of the whole frame matching in the traditional algorithm.Experimental results show good performance and effectiveness the proposed strategy by comparing with the prior arts.展开更多
Flux-limited and volume-limited galaxy samples are constructed from the Sloan Digital Sky Survey（SDSS）data releases DR4,DR6 and DR7 for statistical analysis.The two-point correlation functionsξ（s）,monopole of thr...Flux-limited and volume-limited galaxy samples are constructed from the Sloan Digital Sky Survey（SDSS）data releases DR4,DR6 and DR7 for statistical analysis.The two-point correlation functionsξ（s）,monopole of three-point correlation functionsζ0,projected two-point correlation function wp and pairwise velocity dispersionσ12 are measured to test if galaxy samples are fair for these statistics.We find that with the increment of sky coverage of subsequent data releases in SDSS, ξ（s）of the flux-limited sample is extremely robust and insensitive to local structures at low redshift.However,for volume-limited samples fainter than L＊ at large scales s～10 h-1 Mpc,the deviation of ξ（s）from different SDSS data releases（DR7,DR6 and DR4）increases with the increment of absolute magnitude.The case of ζ0（s）is similar to that ofξ（s）.In the weakly nonlinear regime,there is no agreement between ζ0 of different data releases in all luminosity bins.Furthermore,wp of volume-limited samples of DR7 in luminosity bins fainter than -Mr,0.1=[18.5,19.5]are significantly larger and σ12 of the two faintest volume-limited samples of DR7 display a very different scale dependence than results from DR4 and DR6.Our findings call for caution in understanding clustering analysis results of SDSS faint galaxy samples and higher order statistics of SDSS volume-limited samples in the weakly nonlinear regime.The first zero-crossing points of ξ（s）from volume-limited samples are also investigated and discussed.展开更多
Background:Numerous systematic reviews and meta-analyses have been published that evaluate the association between periodontal disease and systemic diseases,many of which address similar topics.Moreover,their quality ...Background:Numerous systematic reviews and meta-analyses have been published that evaluate the association between periodontal disease and systemic diseases,many of which address similar topics.Moreover,their quality requires assessment.Therefore,we performed a cross-sectional analysis to examine the evidence on the relationship between periodontal disease and systemic diseases.Methods:The PubMed,Embase,Web of Science,and the Cochrane Library databases were systematically searched to identify relevant systematic reviews and meta-analyses.Only studies that considered periodontal disease as the exposure factor and various systemic diseases as the outcome were included.The basic characteristics and pertinent data from the selected studies were extracted.The modified version of A Measurement Tool to Assess Systematic Reviews 2(AMSTAR 2)was employed for quality assessment,while R software was used for statistical analysis.Results:Among the 212 relevant systematic reviews and meta-analyses,57 were finally included in our analysis.These studies involved 75 diseases and 81 disease-related outcomes,with cancer(19/81)being the most frequently addressed topic.Of the 81 outcomes,67 demonstrated a significant association.Notably,the highest risk estimate was found for head and neck cancer[odds ratio(OR)=3.17,95%confidence interval(CI)1.78-5.64],while the lowest was observed for premature rupture of the amniotic sac[relative risk(RR)=1.10,95%CI 1.08-1.12].The methodological quality ratings indicated that approximately 71.93%of included studies were classified as“Critically low”,with another 17.54%rated as“Low”,and only about 10.53%categorized as“Moderate”.Conclusions:Periodontal disease significantly elevates the risks associated with 15 cancer-related,8 cardiovascular-related,8 metabolic-related,and 5 neurological-related outcomes.However,the overall methodological quality of existing systematic reviews and meta-analyses is generally suboptimal and requires enhancement to generate higher-quality evidence in the future.展开更多
Er^(3+)-and Tm^(3+)-doped Ca_(x)Sr_(2-x)Nb_(2)O_(7)(C_(x)S_(2-x)N,x=0.6,0.8,1,0,1.2,1,4) phosphors with layered pe rovskite structure were designed.These phosphors exhibit a dominant emission peak at 549 nm under980 n...Er^(3+)-and Tm^(3+)-doped Ca_(x)Sr_(2-x)Nb_(2)O_(7)(C_(x)S_(2-x)N,x=0.6,0.8,1,0,1.2,1,4) phosphors with layered pe rovskite structure were designed.These phosphors exhibit a dominant emission peak at 549 nm under980 nm laser excitation,attributed to the^(4)S_(3/2)→^(4)I_(15/2)transition.By increasing the content of Ca^(2+),the crystal field regulation of rare earth ions is realized and the luminescence enhancement is induced,which is manifested by the increase of^(2)H_(11/2),^(4)S_(3/2)→^(4)I_(15/2)emission.Furthermore,the temperature sensing sensitivities of C_(0.6)S_(1.4)N:Er,Tm and C_(0.6)S_(1.4)N:Er,Tm based on non-thermally coupled energy levels were studied.Finally,an anti-counterfeiting imprint was prepared using phosphors,which have high brightness and excellent photothermal stability.This work not only confirms that closer ionic radii substitution enables to increase the electronic density of states,improve the crystal field symmetry and enhance the luminescence,but also provides a promising phosphor system for temperature sensing and anti-counterfeiting applications,opening up new prospects in the optimization of the optical properties of phosphors.展开更多
Deoxynivalenol(DON),the most common mycotoxin in the world,poses serious health hazards to both humans and animals and causes significant economic losses to the food and feed industry.An intriguing method for DON deto...Deoxynivalenol(DON),the most common mycotoxin in the world,poses serious health hazards to both humans and animals and causes significant economic losses to the food and feed industry.An intriguing method for DON detoxification involves enzymatic cascade catalysis by pyrroloquinoline quinone-dependent alcohol dehydrogenase(DADH)and aldo-keto reductase(AKR13B3).However,the poor catalytic activity of AKR13B3 has limited its usefulness.Here,structure-guided steric hindrance engineering,computer-assisted protein engineering,and combinatorial mutagenesis were carried out to increase the catalytic efficiency of AKR13B3.The best mutant in this project was M28S/S65V,which outperformed wild-type AKR13B3 in terms of catalytic efficiency(kcat/Km)and specific activity by factors of 44.07 and 41.65,respectively.Kinetic parameter determination revealed that the enhanced catalytic efficiency of M28S/S65V toward 3-keto-DON was attributed to the decreased Km and increased kcat values.Moreover,the engineered enzyme was applied to degrade DON in contaminated corn steep liquor,for a 90.62%removal rate.Structure-based computational analysis provided insights into the enhanced catalytic efficiency of M28S/S65V,which was attributed to the enlarged substrate-binding pocket and reshaped pocket with a favorable hydrophilic attack distance.The results provide a reference for improving the catalytic activity of an enzyme toward non-native bulky substrates and pave the way for the development of enzymes as detoxification agents to mitigate DON in the food and feed industry.展开更多
基金supported by the"Fundamental Research Funds for the Central Universities"(Grant No.30924010801).
文摘In this study,the potential application of shaped charge jets as transient antennas for electromagnetic signal transmission was explored and an electromagnetic pulse radiation system with a shaped charge jet as a transient antenna was proposed.During the research,crucial characteristics of the transient antenna formed by a shaped charge with a 30 mm diameter,such as resonant frequency,radiation pattern,and radiation efficiency,were evaluated.The typical shaped charge jet morphology was obtained based on the simulations,in which it could insight the dynamic behavior of the shaped charge jet selected.An equivalent model experiment was employed to test the radiation efficiency,and it showed that a shorting pin loading method could increase the relative bandwidth of the jet antenna to 32.8%,and the experimental results correlate with the theoretical predictions for half-wave dipole antennas reasonably well.Additionally,variations in the diameter of the shaped charge jet were found to affect the input impedance and impedance bandwidth,while the length of the jet influenced the resonant frequency of the antenna.This suggests that altering these parameters can achieve reconfigurability of the jet antenna.
基金supported by the Polar Research Institute of China and the Chinese Arctic and Antarctic Administrationsupported by the Chinese Academy of Science Key Instrument(ZDKYYQ20200008)the National Natural Science Foundation of China(12473094 and 12273070).
文摘The redshifted 21 cm line,arising from neutral hydrogen,offers a unique probe into the intergalactic medium and the first stars and galaxies formed in the early universe.However,detecting this signal is a challenging task because of artificial radio-frequency interference(RFI)and systematic errors such as ground effects.The interior of the Antarctic continent provides an excellent location to make such observations,with minimal RFI and relatively stable foreground signals.Moreover,a flat plateau in central Antarctica,with an ice cap over 2000 m deep,will show less ground reflection of radio waves,reducing the signal complexity in the area around the probing antenna.It may be advantageous to perform cosmological 21 cm experiments in Antarctica,and a 21 cm Antarctic global spectrum experiment can potentially be deployed on the Antarctic ice cap.We have performed preliminary instrumental design,system calibration,and implementation of such an instrument optimized for extreme cold and capable of long-term autonomous operation.This system shows the ability to effectively detect the 21 cm signal,confirming Antarctica as an excellent observational site for radio cosmology.
基金funded by Beijing Municipal Key Specialty Construction Project of Traditional Chinese Medicine[(1+X+N)2017].
文摘Facial paralysis comorbidities is now understood to include two distinct forms:synkinesis and micro-entrapment syndrome of nerves innervating the face(MESNIF).These disorders manifest as oromandibular synkinesis,stiffness and atrophy of facial muscles on one side,which affect activities of daily living.Acupoint Injection is a treatment for facial paralysis,combining the meridian theory of traditional Chinese medicine,with the injection of specific drugs into acupuncture points of the face.In recent years,the use of acupoint injections has shown in remarkable clinical efficacy and few adverse effects.We report the case to introduce this integrative therapy and outline the key principles of rehabilitation therapy.
基金financially supported by the National Natural Science Foundation of China(No.52102470)。
文摘Though the lithium-ion battery is universally applied,the reliability of lithium-ion batteries remains a challenge due to various physicochemical reactions,electrode material degradation,and even thermal runaway.Accurate estimation and prediction of battery health conditions are crucial for battery safety management.In this paper,an end-cloud collaboration method is proposed to approach the track of battery degradation process,integrating end-side empirical model with cloud-side data-driven model.Based on ensemble learning methods,the data-driven model is constructed by three base models to obtain cloud-side highly accurate results.The double exponential decay model is utilized as an empirical model to output highly real-time prediction results.With Kalman filter,the prediction results of end-side empirical model can be periodically updated by highly accurate results of cloud-side data-driven model to obtain highly accurate and real-time results.Subsequently,the whole framework can give an accurate prediction and tracking of battery degradation,with the mean absolute error maintained below 2%.And the execution time on the end side can reach 261μs.The proposed end-cloud collaboration method has the potential to approach highly accurate and highly real-time estimation for battery health conditions during battery full life cycle in architecture of cyber hierarchy and interactional network.
基金Project supported by the State Key Laboratory for Advanced Metals and Materials(2019Z-14)。
文摘In this paper,we systematically investigated the microstructure evolution and coercivity mechanism of hydrogenation-disproportionation-desorption-recombination(HDDR)treated Nd-Fe-B strip cast alloys by transmission electron microscopy(TEM)and three-dimensional atom probe(3 DAP)analyses.The rodlike NdH_(2+x) phases with diameters of 10-20 nm are embedded intoα-Fe matrix,which hereditarily leads to textured grains in HDDR alloy.The migration of NdH_(2+x) from Nd-rich region toα-Fe matrix during hydrogen absorption process contributes to the uniform redistribution of Nd-rich phases after HDDR treatment The HDDR alloy with single domain grain sizes of 200-300 nm exhibits relatively low coercivity of 1.01 T that arises from pinning magnetic domain motion.The weak c-axis orientation of HDDR alloy results in a lower reverse magnetic field(coercivity)to reduce remanence to 0.Moreover,the direct contact of Nd_(2)Fe_(14)B grains and the high concentration of ferromagnetic elements(Fe content≈66.06 at%,Co content≈0.91 at%)in Nd-rich grain boundary layer lead to strong magnetostatic coupling effect among Nd_(2) Fe_(14)B grains.The nano-sized a-Fe inside Nd_(2) Fe_(14)B matrix makes the magnetization reversal easily and decreases the coercivity of HDDR alloy.
基金supported by the Natural Science Funds for Distinguished Young Scholar (Grant No. 11602110)Jiangsu Province Graduate Research and Practice Innovation Program (No.KY CX180471)。
文摘The use of a shaped liner driven by electromagnetic force is a new means of forming jets. To study the mechanism of jet formation driven by electromagnetic force, we considered the current skin effect and the characteristics of electromagnetic loading and established a coupling model of "ElectriceMagnetic eForce" and the theoretical model of jet formation under electromagnetic force. The jet formation and penetration of conical and trumpet liners have been calculated. Then, a numerical simulation of liner collapse under electromagnetic force, jet generation, and the stretching motion were performed using an ANSYS multiphysics processor. The calculated jet velocity, jet shape, and depth of penetration were consistent with the experimental results, with a relative error of less than 10%. In addition, we calculated the jet formation of different curvature trumpet liners driven by the same loading condition and obtained the influence rule of the curvature of the liner on jet formation. Results show that the theoretical model and the ANSYS multiphysics numerical method can effectively calculate the jet formation of liners driven by electromagnetic force, and in a certain range, the greater the curvature of the liner is, the greater the jet velocity is.
基金financially supported by the National Natural Science Foundation of China(No.52102470)。
文摘The large-scale application of lithium metal batteries remains a challenge due to the hydrolysis of LiPF_(6),which can induce capacity fade and series of safety issues.Prof.Ma and his co-workers have designed a hydrophobic Li^(+)-solvated structure to obtain high performances lithium metal batteries.The specific functional groups of theadditive,hexafluoroisopropyl acrylate.
基金the National Key R&D Program of China(2022YFF0709101)the National Natural Science Foundation of China(NSFC)under grant Nos.61621001,62105244,12003016 and 12204353.
文摘The Solar Upper Transition Region Imager(SUTRI)focuses on the solar transition region to achieve dynamic imaging observation of the upper transition region.In this paper,we report the optical system design,mechanical design,ultrasmooth mirror manufacture and measurement,EUV multilayer film coating,prelaunch installation and calibration for the SUTRI payload at IPOE,Tongji University.Finally,the SUTRI carried by the SATech-01 satellite was successfully set to launch.All functions of this telescope were normal,and the observation results obtained in orbit were consistent with the design.
基金financially supported by the National Natural Science Foundation of China(No.52102470)the Science and Technology Development Project of Jilin province(No.20200501012GX)。
文摘As the lithium-ion battery is widely applied,the reliability of the battery has become a high-profile content in recent years.Accurate estimation and prediction of state of health(SOH)and remaining useful life(RUL)prediction are crucial for battery management systems.In this paper,the core contribution is the construction of a datadriven model with the long short-term memory(LSTM)network applicable to the time-series regression prediction problem with the integration of two methods,data-driven methods and feature signal analysis.The input features of model are extracted from differential thermal voltammetry(DTV)curves,which could characterize the battery degradation characteristics,so that the accurate prediction of battery capacity fade could be accomplished.Firstly,the DTV curve is smoothed by the Savitzky-Golay filter,and six alternate features are selected based on the connection between DTV curves and battery degradation characteristics.Then,a correlation analysis method is used to further filter the input features and three features that are highly associated with capacity fade are selected as input into the data driven model.The LSTM neural network is trained by using the root mean square propagation(RMSprop)technique and the dropout technique.Finally,the data of four batteries with different health levels are deployed for model construction,verification and comparison.The results show that the proposed method has high accuracy in SOH and RUL prediction and the capacity rebound phenomenon can be accurately estimated.This method can greatly reduce the cost and complexity,and increase the practicability,which provides the basis and guidance for battery data collection and the application of cloud technology and digital twin.
基金National Natural Science Foundation of China(Grant No.11972196)Youth fund of Jiangsu Natural Science Foundation(Grant Nos.BK20190433)National Natural Science Funds for Distinguished Young Scholar of China(Grant No.11702144)to provide fund for conducting experiments.
文摘The influence of a magnetic field on the stability of a shaped charge jet is experimentally investigated at standoffs of 490,650 and 800 mm.The experimental results without and with the magnetic field are compared in terms of the shaped charge jet form,stability and penetration ability.A theoretical model based on one-dimension fluid dynamics is then developed to assess the depth of penetration of the shaped charge at those three standoffs and magnetic conditions.The results show that the penetration capability can be enhanced in more than 70%by the magnetic field.The theoretical calculations are compared with the experimental results with reasonably good correlation.In addition,the parameters introduced in the theory are discussed together with the experiments at three standoffs studied.
基金supported by a grant from National Natural Science Foundation of China(No.30901481,81372752,81472411)Wu-Jie Ping Medical Foundation(320.6750.13261)
文摘In recent years, immunotherapy has been gradually established as the fourth frequently adopted antitumor therapy, following surgery, chemotherapy and radiotherapy, for advanced urologic malignancies with an improved understanding of theoretical basis, such as molecular biology and immunology. Thereinto, adoptive cellular immunotherapy （ACI） has become one of the hotspots, which comprises a variety of treatment approaches, such as TIL, CIK cell, ~＇~ T cell, CAR-engineered T cell and Allogeneie stem cell transplantation （alloSCT）. Although preclinical efficacy has been demonstrated remarkably, clinical trials could not consistently show the benefit due to multi-factors in complex immnnosuppressive microenvironment in vivo compared to that of in vitro. Here we review some timely aspects of ACI for advanced urologic malignancies, and describe the current status and limitation of immunotherapy from the cellular level. It＇s our expectation to provide prompting consideration of novel combinatorial ACI strategies and a resurgence of interest in ACI for advanced urologic malignancies.
文摘The bidding strategies of power suppliers to maximize their interests is of great importance.The proposed bilevel optimization model with coalitions of power suppliers takes restraint factors into consideration,such as operating cost reduction,potential cooperation,other competitors’bidding behavior,and network constraints.The upper model describes the coalition relationship between suppliers,and the lower model represents the independent system operator’s optimization without network loss(WNL)or considering network loss(CNL).Then,a novel algorithm,the evolutionary game theory algorithm(EGA)based on a hybrid particle swarm optimization and improved firefly algorithm(HPSOIFA),is proposed to solve the bi-level optimization model.The bidding behavior of the power suppliers in equilibrium with a dynamic power market is encoded as one species,with the EGA automatically predicting a plausible adaptation process for the others.Individual behavior changes are employed by the HPSOIFA to enhance the ability of global exploration and local exploitation.A novel improved firefly algorithm(IFA)is combined with a chaotic sequence theory to escape from the local optimum.In addition,the Shapley value is applied to the profit distribution of power suppliers’cooperation.The simulation,adopting the standard IEEE-30 bus system,demonstrates the effectiveness of the proposed method for solving the bi-level optimization problem.
文摘Objective:We carried out a meta-analysis to assess the effectiveness and safety of radiotherapy combined with surgery for gastric cancer.Methods:Randomized Clinical Trials (RCTs) in which radiotherapy (preoperative,intraoperative and postoperative),was compared with surgery alone in resectable gastric cancer were identified by searching Cochrane Library (Issue 2,2009),PubMed (Jan 1966-Jun 2009),EMBASE (Jan 1974-Jun 2009),Chinese Biomedical Literature Database (Jan 1978-Jun 2009),Chinese Science and Technology Periodicals Database (Jan 1989-Jun 2009),China National Knowledge Infrastructure (Jan 1994-Jun 2009) and Wanfang database (Jan 1997-Jun 2009) in English and Chinese languang.Two researchers assessed the quality of included randomized controlled trials (RCT) extracted data independently.The RevMan 5.0 software was used for meta-analysis.Our researchers assessed the quality of included randomized controlled trials (RCT) extracted data independently.The RevMan 5.0 software was used for meta-analysis.Results:Nine randomized controlled trials of 1 548 patients were selected for meta-analysis.Five randomized controlled trials were related with comparison of preoperative radiotherapy plus surgery with single surgery.Two randomized controlled trials were the comparative studies between surgery plus postoperative and single surgery.The meta-analysis results showed that:(1) compared with surgery alone,preoperative radiotherapy combined with surgery can increase 3 years (OR=1.78;95% CI 1.14-2.78,P=0.01),5 years (OR=1.67;95% CI 1.22-2.29,P=0.001),10 years (OR=1.64;95% CI 1.03-2.60,P=0.04) survival rate and resection rate (OR=2.15;95% CI 1.31-3.54,P=0.003);reduce the of tumor recurrence rate (OR=0.59;95% CI 0.37-0.92,P=0.02) and metastasis rate (OR=0.44;95% CI 0.27-0.73,P=0.001);(2) The tumor recurrent rates (OR=0.19,95% CI 0.03-1.14,P=0.07) and tumor metastasis rate (OR=0.09;95% CI 0.00-1.77,P=0.11) had no difference between single surgery group and peri-operative radiotherapy plus surgery group;(3) Postoperative radiotherapy compared with surgery alone had no significant effects on 1 year (OR=0.83;95% CI 0.60-1.15,P=0.26) and 3 years (OR=0.75;95% CI 0.51-1.11,P=0.15) survival rate compared with single surgery,but the 5-year survival rates (OR=0.57;95% CI 0.34-0.95,P=0.03) of the patients who received surgery alone was higher than those who received combined therapy.No difference of the tumor recurrence rate (OR=0.59;95% CI 0.33-1.05,P=0.07),tumor metestasis rate (OR=0.90;95% CI 0.51-1.59,P=0.71) and anastomotic leak (OR=0.98;95% CI 0.25-3.65,P=0.98) were observed between the two groups.Conclusion:Preoperative radiotherapy combined surgery is more rational and effective than surgery alone of gastric cancer.However,in terms of the clinical effects of perioperarive or postoperative radoiotherapy combined with surgery,much multicenter,largescale,high-quality,double-blind and rigorously designed studies would be needed than currently available in the future.
基金supported by the National Natural Science Foundation of China(No.52102470).
文摘To develop emerging electrode materials and improve the performances of batteries,the machine learning techniques can provide insights to discover,design and develop battery new materials in high-throughput way.In this paper,two deep learning models are developed and trained with two feature groups extracted from the Materials Project datasets to predict the battery electrochemical performances including average voltage,specific capacity and specific energy.The deep learning models are trained with the multilayer perceptron as the core.The Bayesian optimization and Monte Carlo methods are applied to improve the prediction accuracy of models.Based on 10 types of ion batteries,the correlation coefficients are maintained above 0.9 compared to DFT calculation results and the mean absolute error of the prediction results for voltages of two models can reach 0.41 V and 0.20 V,respectively.The electrochemical performance prediction times for the two trained models on thousands of batteries are only 72.9 ms and 75.7 ms.Besides,the two deep learning models are applied to approach the screening of emerging electrode materials for sodium-ion and potassium-ion batteries.This work can contribute to a high-throughput computational method to accelerate the rational and fast materials discovery and design.
基金supported by the National Basic Research Program of China (2014CB921104)the National Natural Science Foundation of China (Grant Nos. 51222103, 11274113, 11474067, and 51171047)the support from the Program for New Century Excellent Talents in University (NCET-12-0132)
文摘The exchange-coupled [Co/Ni]N/Tb Fe nano-magnetic films can display strong perpendicular magnetic anisotropy(PMA) which depends on the Tb:Fe component ratio, Tb Fe layer thickness and the repetition number N of [Co/Ni]Nmultilayer. Perpendicular spin valves in the nano thickness scale, consisting of a [Co/Ni]3free and a [Co/Ni]5/Tb Fe reference multilayer, show high giant magnetoresistance(GMR) signal of 6.5 % and a large switching field difference over3 k Oe. However, unexpected slanting of the free layer magnetization, accompanied by a reduced GMR ratio, was found to be caused by the presence of a thick Fe-rich or even a thin but Tb-rich Tb Fe layer. We attribute this phenomenon to the large magnetostriction effect of Tb Fe which probably induces strong stress acting on the free layer and hence reduces its interfacial PMA.
基金funded by the National Natural Science Foundation of China(61872203 and 61802212)the Shandong Provincial Natural Science Foundation(ZR2019BF017)+3 种基金Major Scientific and Technological Innovation Projects of Shandong Province(2019JZZY010127,2019JZZY010132,and 2019JZZY010201)Jinan City“20 universities”Funding Projects Introducing Innovation Team Program(2019GXRC031)Plan of Youth Innovation Team Development of colleges and universities in Shandong Province(SD2019-161)the Project of Shandong Province Higher Educational Science and Technology Program(J18KA331).
文摘This paper presents an algorithm to solve the problem of Photo-Response Non-Uniformity(PRNU)noise facing stabilized video.The stabilized video undergoes in-camera processing like rolling shutter correction.Thus,misalignment exists between the PRNU noises in the adjacent frames owing to the global and local frame registration performed by the in-camera processing.The misalignment makes the reference PRNU noise and the test PRNU noise unable to extract and match accurately.We design a computing method of maximum likelihood estimation algorithm for extracting the PRNU noise from stabilized video frames.Besides,unlike most prior arts tending to match the PRNU noise in whole frame,we propose a new patch-based matching strategy,aiming at reducing the influence from misalignment of frame the PRNU noise.After extracting the reference PRNU noise and the test PRNU noise,this paper adopts the reference and the test PRNU overlapping patch-based matching.It is different from the traditional matching method.This paper conducts different experiments on 224 stabilized videos taken by 13 smartphones in the VISION database.The area under curve of the algorithm proposed in this paper is 0.841,which is significantly higher than 0.805 of the whole frame matching in the traditional algorithm.Experimental results show good performance and effectiveness the proposed strategy by comparing with the prior arts.
基金funded by the National Science Foundation of China (NSFC) under grant Nos.10643002,10633040,10621303,10873035,and 10725314the National Basic Research Program of China (973 program,No. 2007CB815402)
文摘Flux-limited and volume-limited galaxy samples are constructed from the Sloan Digital Sky Survey（SDSS）data releases DR4,DR6 and DR7 for statistical analysis.The two-point correlation functionsξ（s）,monopole of three-point correlation functionsζ0,projected two-point correlation function wp and pairwise velocity dispersionσ12 are measured to test if galaxy samples are fair for these statistics.We find that with the increment of sky coverage of subsequent data releases in SDSS, ξ（s）of the flux-limited sample is extremely robust and insensitive to local structures at low redshift.However,for volume-limited samples fainter than L＊ at large scales s～10 h-1 Mpc,the deviation of ξ（s）from different SDSS data releases（DR7,DR6 and DR4）increases with the increment of absolute magnitude.The case of ζ0（s）is similar to that ofξ（s）.In the weakly nonlinear regime,there is no agreement between ζ0 of different data releases in all luminosity bins.Furthermore,wp of volume-limited samples of DR7 in luminosity bins fainter than -Mr,0.1=[18.5,19.5]are significantly larger and σ12 of the two faintest volume-limited samples of DR7 display a very different scale dependence than results from DR4 and DR6.Our findings call for caution in understanding clustering analysis results of SDSS faint galaxy samples and higher order statistics of SDSS volume-limited samples in the weakly nonlinear regime.The first zero-crossing points of ξ（s）from volume-limited samples are also investigated and discussed.
基金supported by the Lanzhou Science and Technology Project(2022-3-8)the Natural Science Foundation of Chongqing(CSTB2024NSCQMSX0043 and cstc2020jcyj-msxmX0079)the Key Scientific Research Project of Education Department of Henan Province(22A320038).
文摘Background:Numerous systematic reviews and meta-analyses have been published that evaluate the association between periodontal disease and systemic diseases,many of which address similar topics.Moreover,their quality requires assessment.Therefore,we performed a cross-sectional analysis to examine the evidence on the relationship between periodontal disease and systemic diseases.Methods:The PubMed,Embase,Web of Science,and the Cochrane Library databases were systematically searched to identify relevant systematic reviews and meta-analyses.Only studies that considered periodontal disease as the exposure factor and various systemic diseases as the outcome were included.The basic characteristics and pertinent data from the selected studies were extracted.The modified version of A Measurement Tool to Assess Systematic Reviews 2(AMSTAR 2)was employed for quality assessment,while R software was used for statistical analysis.Results:Among the 212 relevant systematic reviews and meta-analyses,57 were finally included in our analysis.These studies involved 75 diseases and 81 disease-related outcomes,with cancer(19/81)being the most frequently addressed topic.Of the 81 outcomes,67 demonstrated a significant association.Notably,the highest risk estimate was found for head and neck cancer[odds ratio(OR)=3.17,95%confidence interval(CI)1.78-5.64],while the lowest was observed for premature rupture of the amniotic sac[relative risk(RR)=1.10,95%CI 1.08-1.12].The methodological quality ratings indicated that approximately 71.93%of included studies were classified as“Critically low”,with another 17.54%rated as“Low”,and only about 10.53%categorized as“Moderate”.Conclusions:Periodontal disease significantly elevates the risks associated with 15 cancer-related,8 cardiovascular-related,8 metabolic-related,and 5 neurological-related outcomes.However,the overall methodological quality of existing systematic reviews and meta-analyses is generally suboptimal and requires enhancement to generate higher-quality evidence in the future.
基金Project supported by the Science and Technology International Cooperation Project of Qinghai Province (2022-HZ-807)the Open Project Salt Lake Chemical Engineering Research Complex,Qinghai University (2023-DXSSZZ-04)。
文摘Er^(3+)-and Tm^(3+)-doped Ca_(x)Sr_(2-x)Nb_(2)O_(7)(C_(x)S_(2-x)N,x=0.6,0.8,1,0,1.2,1,4) phosphors with layered pe rovskite structure were designed.These phosphors exhibit a dominant emission peak at 549 nm under980 nm laser excitation,attributed to the^(4)S_(3/2)→^(4)I_(15/2)transition.By increasing the content of Ca^(2+),the crystal field regulation of rare earth ions is realized and the luminescence enhancement is induced,which is manifested by the increase of^(2)H_(11/2),^(4)S_(3/2)→^(4)I_(15/2)emission.Furthermore,the temperature sensing sensitivities of C_(0.6)S_(1.4)N:Er,Tm and C_(0.6)S_(1.4)N:Er,Tm based on non-thermally coupled energy levels were studied.Finally,an anti-counterfeiting imprint was prepared using phosphors,which have high brightness and excellent photothermal stability.This work not only confirms that closer ionic radii substitution enables to increase the electronic density of states,improve the crystal field symmetry and enhance the luminescence,but also provides a promising phosphor system for temperature sensing and anti-counterfeiting applications,opening up new prospects in the optimization of the optical properties of phosphors.
基金funded by the National Natural Science Foundation of China(32272267)Jiangsu Provincial Frontier Technology Research and Development Program(BF2024073).
文摘Deoxynivalenol(DON),the most common mycotoxin in the world,poses serious health hazards to both humans and animals and causes significant economic losses to the food and feed industry.An intriguing method for DON detoxification involves enzymatic cascade catalysis by pyrroloquinoline quinone-dependent alcohol dehydrogenase(DADH)and aldo-keto reductase(AKR13B3).However,the poor catalytic activity of AKR13B3 has limited its usefulness.Here,structure-guided steric hindrance engineering,computer-assisted protein engineering,and combinatorial mutagenesis were carried out to increase the catalytic efficiency of AKR13B3.The best mutant in this project was M28S/S65V,which outperformed wild-type AKR13B3 in terms of catalytic efficiency(kcat/Km)and specific activity by factors of 44.07 and 41.65,respectively.Kinetic parameter determination revealed that the enhanced catalytic efficiency of M28S/S65V toward 3-keto-DON was attributed to the decreased Km and increased kcat values.Moreover,the engineered enzyme was applied to degrade DON in contaminated corn steep liquor,for a 90.62%removal rate.Structure-based computational analysis provided insights into the enhanced catalytic efficiency of M28S/S65V,which was attributed to the enlarged substrate-binding pocket and reshaped pocket with a favorable hydrophilic attack distance.The results provide a reference for improving the catalytic activity of an enzyme toward non-native bulky substrates and pave the way for the development of enzymes as detoxification agents to mitigate DON in the food and feed industry.
