By simplifying catalyst-product separation and reducing phosphorus waste,heterogeneous hydroformylation offers a more sustainable alternative to homogeneous processes.However,heterogeneous hydroformylation catalysts d...By simplifying catalyst-product separation and reducing phosphorus waste,heterogeneous hydroformylation offers a more sustainable alternative to homogeneous processes.However,heterogeneous hydroformylation catalysts developed thus far still suffer from the issues of much lower activity and metal leaching,which severely hinder their practical application.Here,we demonstrate that incorporating phosphorus(P)atoms into graphitic carbon nitride(PCN)supports facilitates charge transfer from Rh to the PCN support,thus largely enhancing electronic metal-support interactions(EMSIs).In the styrene hydroformylation reaction,the activity of Rh_(1)/PCN single-atom catalysts(SACs)with varying P contents exhibited a volcano-shaped relationship with P doping,where the Rh_(1)/PCN SAC with optimal P doping showed exceptional activity,approximately 5.8-and 3.3-fold greater than that of the Rh_(1)/g-C_(3)N_(4)SAC without P doping and the industrial homogeneous catalyst HRh(CO)(PPh_(3))_(3),respectively.In addition,the optimal Rh_(1)/PCN SAC catalyst also demonstrated largely enhanced multicycle stability without any visible metal aggregation owing to the increased EMSIs,which sharply differed from the severe metal aggregation of large nanoparticles on the Rh_(1)/g-C_(3)N_(4)SAC.Mechan-istic studies revealed that the enhanced catalytic performance could be attributed to electron-deficient Rh species,which reduced CO adsorption while simultaneously promoting alkene adsorption through increased EMSIs.These findings suggest that tuning EMSIs is an effective way to achieve SACs with high activity and durability.展开更多
In Hyperspectral Imaging(HSI),the detrimental influence of noise and distortions on data quality is profound,which has severely affected the following-on analytics and decisionmaking such as land mapping.This study pr...In Hyperspectral Imaging(HSI),the detrimental influence of noise and distortions on data quality is profound,which has severely affected the following-on analytics and decisionmaking such as land mapping.This study presents an innovative framework for assessing HSI band quality and reconstructing the low-quality bands,based on the Prophet model.By introducing a comprehensive quality metric to start,the authors approach factors in both spatial and spectral characteristics across local and global scales.This metric effectively captures the intricate noise and distortions inherent in the HSI data.Subsequently,the authors employ the Prophet model to forecast information within the low-quality bands,leveraging insights from neighbouring high-quality bands.To validate the effectiveness of the authors’proposed model,extensive experiments on three publicly available uncorrected datasets are conducted.In a head-to-head comparison,the framework against six state-ofthe-art band reconstruction algorithms including three spectral methods,two spatialspectral methods and one deep learning method is benchmarked.The authors’experiments also delve into strategies for band selection based on quality metrics and the quality evaluation of the reconstructed bands.In addition,the authors assess the classification accuracy utilising these reconstructed bands.In various experiments,the results consistently affirm the efficacy of the authors’method in HSI quality assessment and band reconstruction.Notably,the authors’approach obviates the need for manually prefiltering of noisy bands.This comprehensive framework holds promise in addressing HSI data quality concerns whilst enhancing the overall utility of HSI.展开更多
This study focused on investigating the effects of various factors on the mechanical properties of superconducting matrix composites reinforced with ferromagnetic particles and interface phases when exposed to externa...This study focused on investigating the effects of various factors on the mechanical properties of superconducting matrix composites reinforced with ferromagnetic particles and interface phases when exposed to external magnetic fields.A micromechanical model was created by simplifying the basic properties and composition of the interface,utilizing principles such as Eshelby’s equivalent inclusion theory and Hooke’s law,as well as applying uniform stress boundary conditions.Through the development of equations,the study predicted changes in effective mechanical properties,highlighting the significant influence of parameters like the interface phase,inclusions,and magnetic field on the effective elastic modulus and magnetostriction of the composite material.By shedding light on these relationships,the research offers valuable insights for the manufacture and application of ferromagnetic particle-reinforced superconducting matrix composites with interface phases,providing a foundation for future research in this area.展开更多
We investigated the ability of NK4, an antagonist of human hepatocyte growth factor （HGF）, to inhibit the influence of HGF on proliferation, migration, invasion and apoptosis of human prostate cancer cells. Expressi...We investigated the ability of NK4, an antagonist of human hepatocyte growth factor （HGF）, to inhibit the influence of HGF on proliferation, migration, invasion and apoptosis of human prostate cancer cells. Expression vector pBudCE4.1-EGFP-NK4 containing NK4 cDNA was used to transfect human prostate cancer DU145 cells, and the effects of the autocrine NK4 on tumor cell proliferation, migration, invasion and apoptosis were assessed in vitro. in vivo, we subcutaneously implanted DU145 cells, mock-transfected clone （DU145/empty vector） cells and NK4- transfected clone （DU145/NK4） cells into nude mice, and then evaluated tumor growth, cell proliferation and cell apoptosis in vivo. We found that DU145/NK4 cells expressed NK4 protein. In the in vitro study, autocrine NK4 at- tenuated the HGF-induced tumor cell proliferation, migration and invasion, and stimulated apoptosis. Furthermore, autocrine NK4 effectively inhibited the HGF-induced phosphorylation of c-Met, extracellular signal-regulated kinase-1 （ERK1）. and protein kinase B 1/2 （Aktl/2）. Histological examination revealed that autocrine NK4 inhibited prolifera- tion and accelerated apoptosis of prostate cancer cells. These results show that genetic modification of DU145 cells with NK4 cDNA yields a significant effect on their proliferation, migration, invasion and apoptosis. Molecular targeting of HGF/c-Met by NK4 could be applied as a novel therapeutic approach to prostate cancer.展开更多
Hydroxylated multi-walled carbon nanotubes(h-MWCNTs) and carboxylated MWCNTs(c-MWCNTs)have potential applications in biomedicine, but their toxicity to human endothelial cells under stressed conditions associated with...Hydroxylated multi-walled carbon nanotubes(h-MWCNTs) and carboxylated MWCNTs(c-MWCNTs)have potential applications in biomedicine, but their toxicity to human endothelial cells under stressed conditions associated with chronic diseases was less studied in vitro. This study stressed human umbilical vein endothelial cells(HUVECs) with ER stress inducer thapsigargin(TG), and investigated the toxicity of h-MWCNTs and c-MWCNTs to normal and stressed HUVECs. h-MWCNTs and c-MWCNTs modestly reduced cellular viability, significantly promoted soluble ICAM-1(sICAM-1),soluble VCAM-1(sVCAM-1) as well as intracellular ROS, and decreased the expression of transcription factor KLF2 and KLF4. Pre-treatment with TG significantly reduced cellular viability, promoted IL-6 and THP-1 monocyte adhesion, and increased the expression of a panel of ER stress genes. ANOVA indicated no interaction between MWCNTs and TG pre-treatment on most of the endpoints. It was concluded that the toxicity of h-MWCNTs and c-MWCNTs to HUVECs might not be exacerbated by ER stress展开更多
BACKGROUND： Serotonin transporter （5-HTT） polymorphisms comprise 5-HTT gene-linked polymorphism region （5-HTTLPR） and variable number of tandem repeats （VNTR）. Studies have revealed an association between 5-HTT...BACKGROUND： Serotonin transporter （5-HTT） polymorphisms comprise 5-HTT gene-linked polymorphism region （5-HTTLPR） and variable number of tandem repeats （VNTR）. Studies have revealed an association between 5-HTT polymorphism and major depressive disorder, which suggests that the ＂S＂ allele of 5-HTTLPR and Stin2.9 of 5-HTTVNTR are associated with major depressive disorder. However, there are a number of studies that do not support the 5-HTT polymorphism effect in major depressive disorder. OBJECTIVE： To study the relationship between 5-HTT gene polymorphism and major depressive disorder in Chinese Han population. DESIGN, TIME AND SETTING： Case-controlled study of 5-HTT gene polymorphism. The experiment was performed at the Central Laboratory, Third Affiliated Hospital of Sun Yat-sen University, China from March 2005 to January 2006. PARTICIPANTS： A total of 99 depressive patients of Chinese Han nationality were recruited for this study. All patients met DSM-IV diagnostic criteria for major depressive disorder and had a total score of Hamilton Depression Scale （24 items） ≥21 points. In addition, 101 healthy subjects, matched for age and gender, served as the control group. METHODS： Venous blood was collected from all subjects. 5-HTT genotypes and alleles were determined by polymerase chain reaction. Consistent with the Hardy-Weinberg equilibrium, the association between 5-HTT gene polymorphism and major depressive disorder were analyzed by Chi-square test. MAIN OUTCOME MEASURES： 5-HTTLPR and 5-HTTVNTR genotypes and allele frequencies were measured. RESULTS： No significant differences in 5-HTTLPR genotypes and allele frequencies were determined between patients and controls （P 〉 0.05）. However, significant differences in 5-HTTVNTR genotypes and allele frequencies were detected （P 〈 0.01 ）. The Stin2.10 allele and 10/10 genotype associated with major depressive disorder （OR = 2.61,7.7, P 〈 0.05; analysis of dose-response relationships Х^2 = 12.35, P 〈 0.01）. CONCLUSION： Results from the present study revealed no association between 5-HTTLPR and major depressive disorder. However, a significant association between 5-HTTVNTR and major depressive disorder existed in a population of Chinese Han. The presence of Stin2.10 and 10/10 genotypes increased the risk for major depressive disorder in a dose-dependent manner.展开更多
In this work,the theoretical analysis and experiment results investigating the influence of plasma-induced reflected wave variations on microwave transmission characterization are presented.Firstly,an analytical trans...In this work,the theoretical analysis and experiment results investigating the influence of plasma-induced reflected wave variations on microwave transmission characterization are presented.Firstly,an analytical transmission line model for transmission characterization of plasma in shock tube is derived and validated against full-wave simulation.Then,the theoretical analysis of transmission characterization based on a time-dependent reconstruction algorithm that takes into account the variations of reflected wave is presented and the influence of reflection variations under various states of plasma is also investigated.The unusual increase in the amplitude of transmitted wave is theoretically predicted and experimentally demonstrated as well.Finally,the experiment results are also presented to illustrate the effects of reflected wave variations in practical microwave transmission characterization of supersonic plasma excited in shock tube.展开更多
Josephson junction plays a key role not only in studying the basic physics of unconventional iron-based superconductors but also in realizing practical application of thin-film based devices,therefore the preparation ...Josephson junction plays a key role not only in studying the basic physics of unconventional iron-based superconductors but also in realizing practical application of thin-film based devices,therefore the preparation of high-quality iron pnictide Josephson junctions is of great importance.In this work,we have successfully fabricated Josephson junctions from Co-doped BaFe_(2)As_(2)thin films using a direct junction fabrication technique which utilizes high energy focused helium ion beam(FHIB).The electrical transport properties were investigated for junctions fabricated with various He^(+)irradiation doses.The junctions show sharp superconducting transition around 24 K with a narrow transition width of 2.5 K,and a dose correlated foot-structure resistance which corresponds to the effective tuning of junction properties by He^(+)irradiation.Significant J_c suppression by more than two orders of magnitude can be achieved by increasing the He^(+)irradiation dose,which is advantageous for the realization of low noise ion pnictide thin film devices.Clear Shapiro steps are observed under 10 GHz microwave irradiation.The above results demonstrate the successful fabrication of high quality and controllable Co-doped BaFe_(2)As_(2)Josephson junction with high reproducibility using the FHIB technique,laying the foundation for future investigating the mechanism of iron-based superconductors,and also the further implementation in various superconducting electronic devices.展开更多
To efficiently and accurately design satellite constellations equipped with Reentry Glide Vehicles(RGVs),new analytical solutions are developed for calculating their coverage perfor-mance.Specifically,a new coverage m...To efficiently and accurately design satellite constellations equipped with Reentry Glide Vehicles(RGVs),new analytical solutions are developed for calculating their coverage perfor-mance.Specifically,a new coverage model is established by approximating the Reentry Reachable Domain(RRD).However,the computation of real-time relative distances between satellites and targets,which is essential for coverage analysis based on this model,imposes a significant compu-tational burden.To address this challenge,a coverage analysis method based on two-dimensional map theory is proposed.This method represents the coverage conditions of a target as a fixed area on a two-dimensional map and transforms the satellite trajectory into a series of parallel lines.By determining the intersection points between these lines and the area boundaries,the coverage ana-lytical solutions for a target point are derived.On this basis,coverage theorems are presented for rapid calculation of the constellation coverage performance for an area.Simulation results demon-strate the effectiveness and high precision of the proposed analytical solutions.展开更多
This paper introduces a novel color image encryption algorithm based on a five-dimensional continuous memristor hyperchaotic system(5D-MHS),combined with a two-dimensional Salomon map and an optimized Arnold transform...This paper introduces a novel color image encryption algorithm based on a five-dimensional continuous memristor hyperchaotic system(5D-MHS),combined with a two-dimensional Salomon map and an optimized Arnold transform.Firstly,convert the test image to a 2D pixel matrix then processed in blocks,and each block of the pixel matrix is permuted with chaotic sequences generated by 5D-MHS and 2D Salomon map.Then,the permuted image is permuted for three rounds with the optimized Arnold algorithm.Finally,one of the chaotic sequences generated by 5D-MHS is employed to diffuse the permuted image to obtain the final ciphertext image.In this paper,several pseudo-random sequences are generated and mixed in the permutation stage to achieve higher security.The algorithm achieves a key space of 2472,the information entropy of the ciphertext image for the color image is 7.9998,number of pixels change rate(NPCR)and unified average changing intensity(UACI)reached 99.6131%and 33.4361%,respectively,and the correlation between pixels is close to 0.The simulation results show that the encryption algorithm is efficient and the key system is secure.展开更多
目的:分析EX-PRESS引流钉联合生物羊膜植入术治疗原发性开角型青光眼(primary open angle glaucoma,POAG)的有效性及安全性。方法:回顾性分析2015-01/2017-02在我院接受EXPRESS引流钉(P50)+羊膜植入术(31例38眼,试验组)与单纯EX-PRESS...目的:分析EX-PRESS引流钉联合生物羊膜植入术治疗原发性开角型青光眼(primary open angle glaucoma,POAG)的有效性及安全性。方法:回顾性分析2015-01/2017-02在我院接受EXPRESS引流钉(P50)+羊膜植入术(31例38眼,试验组)与单纯EX-PRESS引流钉(P50)植入术(22例34眼,对照组)患者的临床资料,统计分析两组术前,术后1d,1wk,3、6mo眼压变化、滤过泡情况以及并发症发生率。结果:术后各个时间点上,试验组及对照组的平均眼压均较术前明显下降,其差异有统计学意义(P<0.05),术后1d,1wk,试验组与对照组平均眼压差异无统计学意义(P>0.05),在术后3、6mo,对照组眼压较试验组眼压高,其差异有统计学意义(P<0.05)。在术后3mo,试验组中功能性滤过泡比例较对照组高,其差异有统计学意义(P<0.05),试验组和对照组术后并发症主要包括浅前房、出血、虹膜后粘连、角膜水肿,两组中其发生率差异无统计学意义(P>0.05)。结论:EX-PRESS引流钉植入术联合生物羊膜植入可以安全有效降低眼压,改善术后滤过泡情况,并有远期降低眼压的作用。展开更多
Efficient experiment design is of great significance for the validation of simulation model with high nonlinearity and large input space.Excessive validation experiment raises the cost while insufficient test increase...Efficient experiment design is of great significance for the validation of simulation model with high nonlinearity and large input space.Excessive validation experiment raises the cost while insufficient test increases the risks of accepting an invalid model.In this paper,an adaptive sequential experiment design method combining global exploration criterion and local exploitation criterion is proposed.The exploration criterion utilizes discrepancy metric to improve the space-filling property of the design points while the exploitation criterion employs the leave one out error to discover informative points.To avoid the clustering of samples in the local region,an adaptive weight updating approach is provided to maintain the balance between exploration and exploitation.Besides,the credibility distribution function characterizing the relationship between the input and result credibility is introduced to support the model validation experiment design.Finally,six benchmark problems and an engineering case are applied to examine the performance of the proposed method.The experiments indicate that the proposed method achieves satisfactory performance for function approximation in accuracy and convergence.展开更多
Rapid dissemination of antibiotic resistance genes among bacterial isolates is an increasing problem in China. Integron, a conserved DNA sequence, which is carried on episomal genetic structures, plays a very importan...Rapid dissemination of antibiotic resistance genes among bacterial isolates is an increasing problem in China. Integron, a conserved DNA sequence, which is carried on episomal genetic structures, plays a very important role in development of antibiotic resistance. This systematic analysis was based on MEDLINE and EMBASE databases. We summarized the distribution and proportion of different types of gene cassette arrays ofintegrons （including class 1, 2, 3 and atypical class 1 integron） from clinical bacteria isolates in China. Fifty-six literatures were included in this study. Most of the strains were Gram-negative bacteria （94.1%, 7,364/7,822） while only 5.9% strains were Gram- positive bacteria. Class 1 integrons were detected in 54.2% （3956/7295） Gram-negative strains, aadA2 was the most popular gene cassette array detected from 60 Gram-positive bacteria while dfrA 17-aadA5 were detected in 426 Gram- negative bacteria. This study identified 12 novel gene cassette arrays which have not been previously found in any species. All the novel gene cassette arrays were detected from Gram-negative bacteria. A regional characteristic of distribution of integrons was presented in this study. The results highlight a need for continuous surveillance of integrons and provide a guide for future research on integron-mediated bacteria resistance.展开更多
With the explosion of the number of meteoroid/orbital debris in terrestrial space in recent years, the detection environment of spacecraft becomes more complex. This phenomenon causes most current detection methods ba...With the explosion of the number of meteoroid/orbital debris in terrestrial space in recent years, the detection environment of spacecraft becomes more complex. This phenomenon causes most current detection methods based on machine learning intractable to break through the two difficulties of solving scale transformation problem of the targets in image and accelerating detection rate of high-resolution images. To overcome the two challenges, we propose a novel noncooperative target detection method using the framework of deep convolutional neural network.Firstly, a specific spacecraft simulation dataset using over one thousand images to train and test our detection model is built. The deep separable convolution structure is applied and combined with the residual network module to improve the network’s backbone. To count the different shapes of the spacecrafts in the dataset, a particular prior-box generation method based on K-means cluster algorithm is designed for each detection head with different scales. Finally, a comprehensive loss function is presented considering category confidence, box parameters, as well as box confidence. The experimental results verify that the proposed method has strong robustness against varying degrees of luminance change, and can suppress the interference caused by Gaussian noise and background complexity. The mean accuracy precision of our proposed method reaches 93.28%, and the global loss value is 13.252. The comparative experiment results show that under the same epoch and batchsize, the speed of our method is compressed by about 20% in comparison of YOLOv3, the detection accuracy is increased by about 12%, and the size of the model is reduced by nearly 50%.展开更多
The NS5A non-structural protein of classical swine fever virus(CSFV)is a multifunctional protein involved in viral genomic replication,protein translation,assembly of infectious virus particles,and regulation of cellu...The NS5A non-structural protein of classical swine fever virus(CSFV)is a multifunctional protein involved in viral genomic replication,protein translation,assembly of infectious virus particles,and regulation of cellular signaling pathways.Previous report showed that NS5A inhibited nuclear factor kappa B(NF-κB)signaling induced by poly(I:C);however,the mechanism involved has not been elucidated.Here,we reported that NS5A directly interacted with NF-κB essential modulator(NEMO),a regulatory subunit of the IκB kinase(IKK)complex,to inhibit the NF-κB signaling pathway.Further investigations showed that the zinc finger domain of NEMO and the aa 126–250 segment of NS5A are essential for the interaction between NEMO and NS5A.Mechanistic analysis revealed that NS5A mediated the proteasomal degradation of NEMO.Ubiquitination assay showed that NS5A induced the K27-linked but not the K48-linked polyubiquitination of NEMO for proteasomal degradation.In addition,NS5A blocked the K63-linked polyubiquitination of NEMO,thus inhibiting IKK phosphorylation,IκBαdegradation,and NF-κB activation.These findings revealed a novel mechanism by which CSFV inhibits host innate immunity,which might guide the drug design against CSFV in the future.展开更多
Cystatin C,cathepsin S,and IL-1 are three important biomarkers of atherosclerosis.Previous studies emphasized the relationship between individual biomarkers in coronary artery disease（CAD） patients and severity of a...Cystatin C,cathepsin S,and IL-1 are three important biomarkers of atherosclerosis.Previous studies emphasized the relationship between individual biomarkers in coronary artery disease（CAD） patients and severity of atherosclerostic lesions of the coronary arteries,while combined cystatin C,cathepsin S,and IL-1 have not been reported for clinical classification of CAD.We aimed to establish a link between cystatin C,cathepsin S,IL-1 and CAD in this cohort study.Totally 112 subjects were enrolled and divided into the stable angina pectoris group,the unstable angina pectoris group and the acute myocardial infarction（AMI） groups,and 50 healthy adults served as controls.The levels of the three biomarkers were detected by ELISA.The results showed that serum level of cystatin C（mg/L） was higher in CAD patients compared with those in the healthy controls（AMI vs.unstable angina pectoris vs.stable angina pectoris vs.controls：1.27±0.18 vs.1.09±0.19 vs.0.91±0.05 vs.0.78±0.07,all P〈0.01）.Cathepsin S（ng/mL） was also significantly different among the groups（AMI vs.unstable angina pectoris vs.stable angina pectoris vs.controls：67.30±8.36 vs.56.90±7.16 vs.49.8±2.72 vs.67.30±8.36,all P〈0.01）.IL-1（pg/mL） was significantly different among the groups as well（AMI vs.unstable angina pectoris vs.stable angina pectoris vs.controls：2.96±0.57 vs.2.46±0.24 vs.2.28±0.09 vs.2.02±0.13,all P〈0.01）.Spearman＇s correlation test revealed positive correlation between cystatin C,cathepsin S,IL-1 and Gensini score（r=0.451,0.491,0.397,respectively）.It is suggested that simultaneous detection of cystatin C,cathepsin S,and IL-1 in serum may be useful in clinical classification and assessment of severity of CAD.展开更多
Recently there has been a wide concern on inorganic nanoparticles as drug delivery carriers. CaCO3 particles have shown promising potential for the development of carriers for drugs, but little research had been perfo...Recently there has been a wide concern on inorganic nanoparticles as drug delivery carriers. CaCO3 particles have shown promising potential for the development of carriers for drugs, but little research had been performed regarding their safe dosage for maximizing the therapeutic activity without harming biosystems. In this study, we assessed the biological safety of porous spherical CaCO3 microparticles on Hela cells. The reactive oxygen species (ROS), glutathione (GSH), carbonyl content in proteins (CCP), DNA-protein crosslinks (DPC) and cell viability were measured. Results showed that with the exposure concentration increase, ROS and CCP in Hela cells presented a significant increase but GSH contents in Hela cells and cell viability showed a significant decrease respectively compared with the control. DPC coefficient ascended, but no statistically significant changes were observed. The results indicated that porous spherical CaCO3 microparticles may induce oxidative damage to Hela cells. But compared with other nanomaterials, porous spherical CaCO3 appeared to have good biocompatibility. The results implied that porous spherical calcium carbonate microparticles could be applied as relatively safe drug vehicles, but with the caveat that the effect of high dosages should not be ignored when attempting to maximize therapeutic activity by increasing the concentration.展开更多
We study the effect of the AlGaN interlayer on structural quality and strain engineering of the GaN films grown on SiC substrates with an AlN buffer layer, hnproved structural quality and tensile stress releasing are ...We study the effect of the AlGaN interlayer on structural quality and strain engineering of the GaN films grown on SiC substrates with an AlN buffer layer, hnproved structural quality and tensile stress releasing are realized in unintentionally doped GaN thin films grown on 6H-SiC substrates by metal organic chemical vapor deposition. Using the optimized AlGaN interlayer, we find that the full width at half maximum of x-ray diffraction peaks for GaN decreases dramatically, indicating an improved crystalline quality. Meanwhile, it is revealed that the biaxial tensile stress in the GaN film is significantly reduced from the Raman results. Photoluminescence spectra exhibit a shift of the peak position of the near-band-edge emission, as well as the integrated intensity ratio variation of the near-band-edge emission to the yellow luminescence band. Thus by optimizing the AlGaN interlayer, we could acquire the high-quality and strain-relaxation GaN epilayer with large thickness on SiC substrates.展开更多
基金supported by the Petrochemical Research Institute Foundation(21-CB-09-01)the National Natural Science Foundation of China(22302186,22025205)+1 种基金the China Postdoctoral Science Foundation(2022M713030,2023T160618)the Fundamental Research Funds for the Central Universities(WK2060000058,WK2060000038).
文摘By simplifying catalyst-product separation and reducing phosphorus waste,heterogeneous hydroformylation offers a more sustainable alternative to homogeneous processes.However,heterogeneous hydroformylation catalysts developed thus far still suffer from the issues of much lower activity and metal leaching,which severely hinder their practical application.Here,we demonstrate that incorporating phosphorus(P)atoms into graphitic carbon nitride(PCN)supports facilitates charge transfer from Rh to the PCN support,thus largely enhancing electronic metal-support interactions(EMSIs).In the styrene hydroformylation reaction,the activity of Rh_(1)/PCN single-atom catalysts(SACs)with varying P contents exhibited a volcano-shaped relationship with P doping,where the Rh_(1)/PCN SAC with optimal P doping showed exceptional activity,approximately 5.8-and 3.3-fold greater than that of the Rh_(1)/g-C_(3)N_(4)SAC without P doping and the industrial homogeneous catalyst HRh(CO)(PPh_(3))_(3),respectively.In addition,the optimal Rh_(1)/PCN SAC catalyst also demonstrated largely enhanced multicycle stability without any visible metal aggregation owing to the increased EMSIs,which sharply differed from the severe metal aggregation of large nanoparticles on the Rh_(1)/g-C_(3)N_(4)SAC.Mechan-istic studies revealed that the enhanced catalytic performance could be attributed to electron-deficient Rh species,which reduced CO adsorption while simultaneously promoting alkene adsorption through increased EMSIs.These findings suggest that tuning EMSIs is an effective way to achieve SACs with high activity and durability.
基金National Natural Science Foundation Major Project of China,Grant/Award Number:42192580Guangdong Province Key Construction Discipline Scientific Research Ability Promotion Project,Grant/Award Number:2022ZDJS015。
文摘In Hyperspectral Imaging(HSI),the detrimental influence of noise and distortions on data quality is profound,which has severely affected the following-on analytics and decisionmaking such as land mapping.This study presents an innovative framework for assessing HSI band quality and reconstructing the low-quality bands,based on the Prophet model.By introducing a comprehensive quality metric to start,the authors approach factors in both spatial and spectral characteristics across local and global scales.This metric effectively captures the intricate noise and distortions inherent in the HSI data.Subsequently,the authors employ the Prophet model to forecast information within the low-quality bands,leveraging insights from neighbouring high-quality bands.To validate the effectiveness of the authors’proposed model,extensive experiments on three publicly available uncorrected datasets are conducted.In a head-to-head comparison,the framework against six state-ofthe-art band reconstruction algorithms including three spectral methods,two spatialspectral methods and one deep learning method is benchmarked.The authors’experiments also delve into strategies for band selection based on quality metrics and the quality evaluation of the reconstructed bands.In addition,the authors assess the classification accuracy utilising these reconstructed bands.In various experiments,the results consistently affirm the efficacy of the authors’method in HSI quality assessment and band reconstruction.Notably,the authors’approach obviates the need for manually prefiltering of noisy bands.This comprehensive framework holds promise in addressing HSI data quality concerns whilst enhancing the overall utility of HSI.
基金supported by the National Natural Science Foundation of China(No.12262020).
文摘This study focused on investigating the effects of various factors on the mechanical properties of superconducting matrix composites reinforced with ferromagnetic particles and interface phases when exposed to external magnetic fields.A micromechanical model was created by simplifying the basic properties and composition of the interface,utilizing principles such as Eshelby’s equivalent inclusion theory and Hooke’s law,as well as applying uniform stress boundary conditions.Through the development of equations,the study predicted changes in effective mechanical properties,highlighting the significant influence of parameters like the interface phase,inclusions,and magnetic field on the effective elastic modulus and magnetostriction of the composite material.By shedding light on these relationships,the research offers valuable insights for the manufacture and application of ferromagnetic particle-reinforced superconducting matrix composites with interface phases,providing a foundation for future research in this area.
文摘We investigated the ability of NK4, an antagonist of human hepatocyte growth factor （HGF）, to inhibit the influence of HGF on proliferation, migration, invasion and apoptosis of human prostate cancer cells. Expression vector pBudCE4.1-EGFP-NK4 containing NK4 cDNA was used to transfect human prostate cancer DU145 cells, and the effects of the autocrine NK4 on tumor cell proliferation, migration, invasion and apoptosis were assessed in vitro. in vivo, we subcutaneously implanted DU145 cells, mock-transfected clone （DU145/empty vector） cells and NK4- transfected clone （DU145/NK4） cells into nude mice, and then evaluated tumor growth, cell proliferation and cell apoptosis in vivo. We found that DU145/NK4 cells expressed NK4 protein. In the in vitro study, autocrine NK4 at- tenuated the HGF-induced tumor cell proliferation, migration and invasion, and stimulated apoptosis. Furthermore, autocrine NK4 effectively inhibited the HGF-induced phosphorylation of c-Met, extracellular signal-regulated kinase-1 （ERK1）. and protein kinase B 1/2 （Aktl/2）. Histological examination revealed that autocrine NK4 inhibited prolifera- tion and accelerated apoptosis of prostate cancer cells. These results show that genetic modification of DU145 cells with NK4 cDNA yields a significant effect on their proliferation, migration, invasion and apoptosis. Molecular targeting of HGF/c-Met by NK4 could be applied as a novel therapeutic approach to prostate cancer.
基金financially supported by College Outstanding Young and Middle-aged Innovative Research Team Project of HubeiProvince (No. T201717)the Health and Family Planning Commission Scientific Research Project of Hubei Province (No. WJ2017Z027)
文摘Hydroxylated multi-walled carbon nanotubes(h-MWCNTs) and carboxylated MWCNTs(c-MWCNTs)have potential applications in biomedicine, but their toxicity to human endothelial cells under stressed conditions associated with chronic diseases was less studied in vitro. This study stressed human umbilical vein endothelial cells(HUVECs) with ER stress inducer thapsigargin(TG), and investigated the toxicity of h-MWCNTs and c-MWCNTs to normal and stressed HUVECs. h-MWCNTs and c-MWCNTs modestly reduced cellular viability, significantly promoted soluble ICAM-1(sICAM-1),soluble VCAM-1(sVCAM-1) as well as intracellular ROS, and decreased the expression of transcription factor KLF2 and KLF4. Pre-treatment with TG significantly reduced cellular viability, promoted IL-6 and THP-1 monocyte adhesion, and increased the expression of a panel of ER stress genes. ANOVA indicated no interaction between MWCNTs and TG pre-treatment on most of the endpoints. It was concluded that the toxicity of h-MWCNTs and c-MWCNTs to HUVECs might not be exacerbated by ER stress
基金a grant from the Foundation of Guangdong Province of Science and Technology,No. 2003C3380
文摘BACKGROUND： Serotonin transporter （5-HTT） polymorphisms comprise 5-HTT gene-linked polymorphism region （5-HTTLPR） and variable number of tandem repeats （VNTR）. Studies have revealed an association between 5-HTT polymorphism and major depressive disorder, which suggests that the ＂S＂ allele of 5-HTTLPR and Stin2.9 of 5-HTTVNTR are associated with major depressive disorder. However, there are a number of studies that do not support the 5-HTT polymorphism effect in major depressive disorder. OBJECTIVE： To study the relationship between 5-HTT gene polymorphism and major depressive disorder in Chinese Han population. DESIGN, TIME AND SETTING： Case-controlled study of 5-HTT gene polymorphism. The experiment was performed at the Central Laboratory, Third Affiliated Hospital of Sun Yat-sen University, China from March 2005 to January 2006. PARTICIPANTS： A total of 99 depressive patients of Chinese Han nationality were recruited for this study. All patients met DSM-IV diagnostic criteria for major depressive disorder and had a total score of Hamilton Depression Scale （24 items） ≥21 points. In addition, 101 healthy subjects, matched for age and gender, served as the control group. METHODS： Venous blood was collected from all subjects. 5-HTT genotypes and alleles were determined by polymerase chain reaction. Consistent with the Hardy-Weinberg equilibrium, the association between 5-HTT gene polymorphism and major depressive disorder were analyzed by Chi-square test. MAIN OUTCOME MEASURES： 5-HTTLPR and 5-HTTVNTR genotypes and allele frequencies were measured. RESULTS： No significant differences in 5-HTTLPR genotypes and allele frequencies were determined between patients and controls （P 〉 0.05）. However, significant differences in 5-HTTVNTR genotypes and allele frequencies were detected （P 〈 0.01 ）. The Stin2.10 allele and 10/10 genotype associated with major depressive disorder （OR = 2.61,7.7, P 〈 0.05; analysis of dose-response relationships Х^2 = 12.35, P 〈 0.01）. CONCLUSION： Results from the present study revealed no association between 5-HTTLPR and major depressive disorder. However, a significant association between 5-HTTVNTR and major depressive disorder existed in a population of Chinese Han. The presence of Stin2.10 and 10/10 genotypes increased the risk for major depressive disorder in a dose-dependent manner.
基金supported by National Natural Science Foundation of China(Nos.62001095 and U20B2043)the Fundamental Research Funds for the Central Universities of China(No.ZYGX2018KYQD200)+1 种基金the National Science and Technology Major Project of the Ministry of Science and Technology of China(No.SQ2019YFA040012)the National Defense Basic Scientific Research Program of China(No.2020-JCJQ-ZD-072)。
文摘In this work,the theoretical analysis and experiment results investigating the influence of plasma-induced reflected wave variations on microwave transmission characterization are presented.Firstly,an analytical transmission line model for transmission characterization of plasma in shock tube is derived and validated against full-wave simulation.Then,the theoretical analysis of transmission characterization based on a time-dependent reconstruction algorithm that takes into account the variations of reflected wave is presented and the influence of reflection variations under various states of plasma is also investigated.The unusual increase in the amplitude of transmitted wave is theoretically predicted and experimentally demonstrated as well.Finally,the experiment results are also presented to illustrate the effects of reflected wave variations in practical microwave transmission characterization of supersonic plasma excited in shock tube.
基金Project supported by the National Key Research and Development Program of China (Grant Nos.2020YFF01014706 and 2017YFC0601901)the National Natural Science Foundation of China (Grant Nos.61571019 and 52177026)。
文摘Josephson junction plays a key role not only in studying the basic physics of unconventional iron-based superconductors but also in realizing practical application of thin-film based devices,therefore the preparation of high-quality iron pnictide Josephson junctions is of great importance.In this work,we have successfully fabricated Josephson junctions from Co-doped BaFe_(2)As_(2)thin films using a direct junction fabrication technique which utilizes high energy focused helium ion beam(FHIB).The electrical transport properties were investigated for junctions fabricated with various He^(+)irradiation doses.The junctions show sharp superconducting transition around 24 K with a narrow transition width of 2.5 K,and a dose correlated foot-structure resistance which corresponds to the effective tuning of junction properties by He^(+)irradiation.Significant J_c suppression by more than two orders of magnitude can be achieved by increasing the He^(+)irradiation dose,which is advantageous for the realization of low noise ion pnictide thin film devices.Clear Shapiro steps are observed under 10 GHz microwave irradiation.The above results demonstrate the successful fabrication of high quality and controllable Co-doped BaFe_(2)As_(2)Josephson junction with high reproducibility using the FHIB technique,laying the foundation for future investigating the mechanism of iron-based superconductors,and also the further implementation in various superconducting electronic devices.
基金supported by the National Natural Science Foundation of China (No.62273119).
文摘To efficiently and accurately design satellite constellations equipped with Reentry Glide Vehicles(RGVs),new analytical solutions are developed for calculating their coverage perfor-mance.Specifically,a new coverage model is established by approximating the Reentry Reachable Domain(RRD).However,the computation of real-time relative distances between satellites and targets,which is essential for coverage analysis based on this model,imposes a significant compu-tational burden.To address this challenge,a coverage analysis method based on two-dimensional map theory is proposed.This method represents the coverage conditions of a target as a fixed area on a two-dimensional map and transforms the satellite trajectory into a series of parallel lines.By determining the intersection points between these lines and the area boundaries,the coverage ana-lytical solutions for a target point are derived.On this basis,coverage theorems are presented for rapid calculation of the constellation coverage performance for an area.Simulation results demon-strate the effectiveness and high precision of the proposed analytical solutions.
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region,China(Nos.2023D01C187 and 2022D01E33)National Natural Science Foundation of China(No.52267010)Tianshan Talent Training Program(Nos.2023TSYCCX0037 and 2023TSYCQNTJ0020).
文摘This paper introduces a novel color image encryption algorithm based on a five-dimensional continuous memristor hyperchaotic system(5D-MHS),combined with a two-dimensional Salomon map and an optimized Arnold transform.Firstly,convert the test image to a 2D pixel matrix then processed in blocks,and each block of the pixel matrix is permuted with chaotic sequences generated by 5D-MHS and 2D Salomon map.Then,the permuted image is permuted for three rounds with the optimized Arnold algorithm.Finally,one of the chaotic sequences generated by 5D-MHS is employed to diffuse the permuted image to obtain the final ciphertext image.In this paper,several pseudo-random sequences are generated and mixed in the permutation stage to achieve higher security.The algorithm achieves a key space of 2472,the information entropy of the ciphertext image for the color image is 7.9998,number of pixels change rate(NPCR)and unified average changing intensity(UACI)reached 99.6131%and 33.4361%,respectively,and the correlation between pixels is close to 0.The simulation results show that the encryption algorithm is efficient and the key system is secure.
文摘目的:分析EX-PRESS引流钉联合生物羊膜植入术治疗原发性开角型青光眼(primary open angle glaucoma,POAG)的有效性及安全性。方法:回顾性分析2015-01/2017-02在我院接受EXPRESS引流钉(P50)+羊膜植入术(31例38眼,试验组)与单纯EX-PRESS引流钉(P50)植入术(22例34眼,对照组)患者的临床资料,统计分析两组术前,术后1d,1wk,3、6mo眼压变化、滤过泡情况以及并发症发生率。结果:术后各个时间点上,试验组及对照组的平均眼压均较术前明显下降,其差异有统计学意义(P<0.05),术后1d,1wk,试验组与对照组平均眼压差异无统计学意义(P>0.05),在术后3、6mo,对照组眼压较试验组眼压高,其差异有统计学意义(P<0.05)。在术后3mo,试验组中功能性滤过泡比例较对照组高,其差异有统计学意义(P<0.05),试验组和对照组术后并发症主要包括浅前房、出血、虹膜后粘连、角膜水肿,两组中其发生率差异无统计学意义(P>0.05)。结论:EX-PRESS引流钉植入术联合生物羊膜植入可以安全有效降低眼压,改善术后滤过泡情况,并有远期降低眼压的作用。
基金supported by the National Natural Science Foundation of China(No.61627810)。
文摘Efficient experiment design is of great significance for the validation of simulation model with high nonlinearity and large input space.Excessive validation experiment raises the cost while insufficient test increases the risks of accepting an invalid model.In this paper,an adaptive sequential experiment design method combining global exploration criterion and local exploitation criterion is proposed.The exploration criterion utilizes discrepancy metric to improve the space-filling property of the design points while the exploitation criterion employs the leave one out error to discover informative points.To avoid the clustering of samples in the local region,an adaptive weight updating approach is provided to maintain the balance between exploration and exploitation.Besides,the credibility distribution function characterizing the relationship between the input and result credibility is introduced to support the model validation experiment design.Finally,six benchmark problems and an engineering case are applied to examine the performance of the proposed method.The experiments indicate that the proposed method achieves satisfactory performance for function approximation in accuracy and convergence.
基金funded by the National Natural Science Foundation of China(No.81000754 and No. 81471994)received a grant from the Key Laboratory for Laboratory Medicine of Jiangsu Province of China(No.XK201114)
文摘Rapid dissemination of antibiotic resistance genes among bacterial isolates is an increasing problem in China. Integron, a conserved DNA sequence, which is carried on episomal genetic structures, plays a very important role in development of antibiotic resistance. This systematic analysis was based on MEDLINE and EMBASE databases. We summarized the distribution and proportion of different types of gene cassette arrays ofintegrons （including class 1, 2, 3 and atypical class 1 integron） from clinical bacteria isolates in China. Fifty-six literatures were included in this study. Most of the strains were Gram-negative bacteria （94.1%, 7,364/7,822） while only 5.9% strains were Gram- positive bacteria. Class 1 integrons were detected in 54.2% （3956/7295） Gram-negative strains, aadA2 was the most popular gene cassette array detected from 60 Gram-positive bacteria while dfrA 17-aadA5 were detected in 426 Gram- negative bacteria. This study identified 12 novel gene cassette arrays which have not been previously found in any species. All the novel gene cassette arrays were detected from Gram-negative bacteria. A regional characteristic of distribution of integrons was presented in this study. The results highlight a need for continuous surveillance of integrons and provide a guide for future research on integron-mediated bacteria resistance.
基金supported by the National Natural Science Foundation of China(No.61473100)。
文摘With the explosion of the number of meteoroid/orbital debris in terrestrial space in recent years, the detection environment of spacecraft becomes more complex. This phenomenon causes most current detection methods based on machine learning intractable to break through the two difficulties of solving scale transformation problem of the targets in image and accelerating detection rate of high-resolution images. To overcome the two challenges, we propose a novel noncooperative target detection method using the framework of deep convolutional neural network.Firstly, a specific spacecraft simulation dataset using over one thousand images to train and test our detection model is built. The deep separable convolution structure is applied and combined with the residual network module to improve the network’s backbone. To count the different shapes of the spacecrafts in the dataset, a particular prior-box generation method based on K-means cluster algorithm is designed for each detection head with different scales. Finally, a comprehensive loss function is presented considering category confidence, box parameters, as well as box confidence. The experimental results verify that the proposed method has strong robustness against varying degrees of luminance change, and can suppress the interference caused by Gaussian noise and background complexity. The mean accuracy precision of our proposed method reaches 93.28%, and the global loss value is 13.252. The comparative experiment results show that under the same epoch and batchsize, the speed of our method is compressed by about 20% in comparison of YOLOv3, the detection accuracy is increased by about 12%, and the size of the model is reduced by nearly 50%.
基金the National Nature Science Foundation of China(Grant No.31972677)the Construction Project of Liaoning Provincial Key Laboratory,China(2022JH13/10200026).
文摘The NS5A non-structural protein of classical swine fever virus(CSFV)is a multifunctional protein involved in viral genomic replication,protein translation,assembly of infectious virus particles,and regulation of cellular signaling pathways.Previous report showed that NS5A inhibited nuclear factor kappa B(NF-κB)signaling induced by poly(I:C);however,the mechanism involved has not been elucidated.Here,we reported that NS5A directly interacted with NF-κB essential modulator(NEMO),a regulatory subunit of the IκB kinase(IKK)complex,to inhibit the NF-κB signaling pathway.Further investigations showed that the zinc finger domain of NEMO and the aa 126–250 segment of NS5A are essential for the interaction between NEMO and NS5A.Mechanistic analysis revealed that NS5A mediated the proteasomal degradation of NEMO.Ubiquitination assay showed that NS5A induced the K27-linked but not the K48-linked polyubiquitination of NEMO for proteasomal degradation.In addition,NS5A blocked the K63-linked polyubiquitination of NEMO,thus inhibiting IKK phosphorylation,IκBαdegradation,and NF-κB activation.These findings revealed a novel mechanism by which CSFV inhibits host innate immunity,which might guide the drug design against CSFV in the future.
基金founded by science and technology planning project of Xuzhou City(No.KC14SH088)
文摘Cystatin C,cathepsin S,and IL-1 are three important biomarkers of atherosclerosis.Previous studies emphasized the relationship between individual biomarkers in coronary artery disease（CAD） patients and severity of atherosclerostic lesions of the coronary arteries,while combined cystatin C,cathepsin S,and IL-1 have not been reported for clinical classification of CAD.We aimed to establish a link between cystatin C,cathepsin S,IL-1 and CAD in this cohort study.Totally 112 subjects were enrolled and divided into the stable angina pectoris group,the unstable angina pectoris group and the acute myocardial infarction（AMI） groups,and 50 healthy adults served as controls.The levels of the three biomarkers were detected by ELISA.The results showed that serum level of cystatin C（mg/L） was higher in CAD patients compared with those in the healthy controls（AMI vs.unstable angina pectoris vs.stable angina pectoris vs.controls：1.27±0.18 vs.1.09±0.19 vs.0.91±0.05 vs.0.78±0.07,all P〈0.01）.Cathepsin S（ng/mL） was also significantly different among the groups（AMI vs.unstable angina pectoris vs.stable angina pectoris vs.controls：67.30±8.36 vs.56.90±7.16 vs.49.8±2.72 vs.67.30±8.36,all P〈0.01）.IL-1（pg/mL） was significantly different among the groups as well（AMI vs.unstable angina pectoris vs.stable angina pectoris vs.controls：2.96±0.57 vs.2.46±0.24 vs.2.28±0.09 vs.2.02±0.13,all P〈0.01）.Spearman＇s correlation test revealed positive correlation between cystatin C,cathepsin S,IL-1 and Gensini score（r=0.451,0.491,0.397,respectively）.It is suggested that simultaneous detection of cystatin C,cathepsin S,and IL-1 in serum may be useful in clinical classification and assessment of severity of CAD.
文摘Recently there has been a wide concern on inorganic nanoparticles as drug delivery carriers. CaCO3 particles have shown promising potential for the development of carriers for drugs, but little research had been performed regarding their safe dosage for maximizing the therapeutic activity without harming biosystems. In this study, we assessed the biological safety of porous spherical CaCO3 microparticles on Hela cells. The reactive oxygen species (ROS), glutathione (GSH), carbonyl content in proteins (CCP), DNA-protein crosslinks (DPC) and cell viability were measured. Results showed that with the exposure concentration increase, ROS and CCP in Hela cells presented a significant increase but GSH contents in Hela cells and cell viability showed a significant decrease respectively compared with the control. DPC coefficient ascended, but no statistically significant changes were observed. The results indicated that porous spherical CaCO3 microparticles may induce oxidative damage to Hela cells. But compared with other nanomaterials, porous spherical CaCO3 appeared to have good biocompatibility. The results implied that porous spherical calcium carbonate microparticles could be applied as relatively safe drug vehicles, but with the caveat that the effect of high dosages should not be ignored when attempting to maximize therapeutic activity by increasing the concentration.
基金Supported by the National Key R&D Program of China under Grant No 2016YFB0400200
文摘We study the effect of the AlGaN interlayer on structural quality and strain engineering of the GaN films grown on SiC substrates with an AlN buffer layer, hnproved structural quality and tensile stress releasing are realized in unintentionally doped GaN thin films grown on 6H-SiC substrates by metal organic chemical vapor deposition. Using the optimized AlGaN interlayer, we find that the full width at half maximum of x-ray diffraction peaks for GaN decreases dramatically, indicating an improved crystalline quality. Meanwhile, it is revealed that the biaxial tensile stress in the GaN film is significantly reduced from the Raman results. Photoluminescence spectra exhibit a shift of the peak position of the near-band-edge emission, as well as the integrated intensity ratio variation of the near-band-edge emission to the yellow luminescence band. Thus by optimizing the AlGaN interlayer, we could acquire the high-quality and strain-relaxation GaN epilayer with large thickness on SiC substrates.
