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| 1 | Neomycin biosynthesis is regulated positively by AfsA-g and NeoR in Streptomyces fradiae CGMCC 4.7387显示文摘Neomycins are a group of aminoglycoside antibiotics with both clinical and agricultural applications.To elucidate the regulatory mechanism of neomycin biosynthesis,we completed draft genome sequencing of a neomycin producer Streptomyces fradiae CGMCC 4.7387 from marine sediments,and the neomycin biosynthesis gene cluster was identified.Inactivation of the afsA-g gene encoding a γ-butyrolactone(GBL) synthase in S.fradiae CGMCC 4.7387 resulted in a significant decrease of neomycin production.Quantitative RT-PCR analysis revealed that the transcriptional level of neoR and the aphA-neoGH operon were reduced in the afsA-g::aac(3)Ⅳ mutant.Interestingly,a conserved binding site of AdpA,a key activator in the GBL regulatory cascade,was discovered upstream of neoR,a putative regulatory gene encoding a protein with an ATPase domain and a tetratricopeptide repeat domain.When neoR was inactivated,the neomycin production was reduced about 40%in comparison with the WT strain.Quantitative RT-PCR analysis revealed that the transcriptional levels of genes in the aphA-neoGH operon were reduced clearly in the neoR::aac(3)Ⅳ mutant.Finally,the titers of neomycin were improved considerably by overexpression of qfsA-gand neoR in S.fradiae CGMCC 4.7387. | Xiangxi Meng Wenzhao Wang Zhoujie Xie Pengwei Li Yue Li Zhengyan Guo Yingjian Lu Jie Yang Kaile Guan Zhaoxin Lu Huarong Tan Yihua Chen | 2017 | Science China(Life Sciences)2017，60，9： | 7 |
| 2 | Numerical simulation of the dimensional transformation of atomization in a supersonic aerodynamic atomization dust-removing nozzle based on transonic speed compressible flow显示文摘To simulate the transonic atomization jet process in Laval nozzles,to test the law of droplet atomization and distribution,to find a method of supersonic atomization for dust-removing nozzles,and to improve nozzle efficiency,the finite element method has been used in this study based on the COMSOL computational fluid dynamics module.The study results showed that the process cannot be realized alone under the two-dimensional axisymmetric,three-dimensional and three-dimensional symmetric models,but it can be calculated with the transformation dimension method,which uses the parameter equations generated from the two-dimensional axisymmetric flow field data of the three-dimensional model.The visualization of this complex process,which is difficult to measure and analyze experimentally,was realized in this study.The physical process,macro phenomena and particle distribution of supersonic atomization are analyzed in combination with this simulation.The rationality of the simulation was verified by experiments.A new method for the study of the atomization process and the exploration of its mechanism in a compressible transonic speed flow field based on the Laval nozzle has been provided,and a numerical platform for the study of supersonic atomization dust removal has been established. | Tian Zhang Deji Jing Shaocheng Ge Jiren Wang Xiangxi Meng ShuaiShuai Ren | 2020 | International Journal of Coal Science & Technology2020，7，3： | 6 |
| 3 | Mining of a streptothricin gene cluster from Streptomyces sp.TP-A0356 genome via heterologous expression显示文摘Streptothricins (STs) are used commercially to treat bacterial and fungal diseases in agriculture. Mining of the sequenced microbial genomes uncovered two cryptic ST clusters from Streptomyces sp. C and Streptomyces sp. TP-A0356. The ST cluster from S. sp. TP-A0356 was verified by successful heterologous expression in Streptomyces coelicolor M145. Two new ST analogs were produced together with streptothricin F and streptothricin D in the heterologous host. The ST cluster was further confirmed by inactivation of gene stnO, which was proposed encoding an aminomutase supplying -lysines for the poly-β-Lys chain formation. A putative biosynthetic pathway for STs is proposed based on bioinformatics analyses of the ST genes and experimental evidence. | LI JinE GUO ZhengYan HUANG Wei MENG XiangXi AI GuoMin TANG GongLi CHEN YiHua | 2013 | Science China(Life Sciences)2013，56，7： | 3 |
| 4 | Symmetry-enforced three-dimensional Dirac phononic crystals显示文摘Dirac semimetals,the materials featuring fourfold degenerate Dirac points,are critical states of topologically distinct phases.Such gapless topological states have been accomplished by a band-inversion mechanism,in which the Dirac points can be annihilated pairwise by perturbations without changing the symmetry of the system.Here,we report an experimental observation of Dirac points that are enforced completely by the crystal symmetry using a nonsymmorphic three-dimensional phononic crystal.Intriguingly,our Dirac phononic crystal hosts four spiral topological surface states,in which the surface states of opposite helicities intersect gaplessly along certain momentum lines,as confirmed by additional surface measurements.The novel Dirac system may release new opportunities for studying elusive(pseudo)and offer a unique prototype platform for acoustic applications. | Xiangxi Cai Liping Ye Chunyin Qiu Meng Xiao Rui Yu Manzhu Ke Zhengyou Liu | 2020 | Light(Science & Applications)2020，9，1： | 2 |
| 5 | Effects of carbon on Pr_(0.15)Tb_(0.30)Dy_(0.55)Fe_(1.85) compound显示文摘The structure, Curie temperature and magnetostriction of Pr0.15Tb0.30Dy0.55Fe1.85Cx (x=0-0.1) compounds were investigated by X-ray diffraction, a vibrating sample magnetometer and a standard strain technique. All the samples show entirely MgCu2-type Laves phase structure. The lattice parameter and Curie temperature increase with C content increasing. The magnetostriction at high magnetic field shows maximum value at x=0.05. | LIU Heyan LI Yangxian YU Xiao LI Songtao MENG Xiangxi XU Xuewen | 2006 | Rare Metals2006，25，z2： | 1 |
| 6 | Sigma-Mixed Unscented Kalman Filter-Based Fault Detection for Traction Systems in High-Speed Trains显示文摘Fault detection(FD)for traction systems is one of the active topics in the railway and academia because it is the initial step for the running reliability and safety of high-speed trains.Heterogeneity of data and complexity of systems have brought new challenges to the traditional FD methods.For addressing these challenges,this paper designs an FD algorithm based on the improved unscented Kalman filter(UKF)with consideration of performance degradation.It is derived by incorporating a degradation process into the state-space model.The network topology of traction systems is taken into consideration for improving the performance of state estimation.We first obtain the mixture distribution by the mixture of sigma points in UKF.Then,the Lévy process with jump points is introduced to construct the degradation model.Finally,the moving average interstate standard deviation(MAISD)is designed for detecting faults.Verifying the proposed methods via a traction systems in a certain type of trains obtains satisfactory results. | CHENG Chao WANG Weijun MENG Xiangxi SHAO Haidong CHEN Hongtian | 2023 | Chinese Journal of Electronics2023，32，5： | 0 |
| 7 | Food supplements could be an effective improvement of diabetes mellitus:a review显示文摘Diabetes mellitus is a disease of endocrine and metabolism disorders,characterized by hyperglycemia,and increased risk of cardiovascular disease complications.Although oral hypoglycemic drugs have the effect of maintaining blood sugar control in diabetic patients,these drugs still have serious side effects for many patients,such as gastrointestinal diseases related to acarbose.Recently,certain food supplements and their bioactive ingredients have been shown to improve diabetes mellitus and can be readily found in the marketplace.This literature review focuses on food supplements with a hypoglycemic function,with an emphasis on their biologically active ingredients and pharmacological effects.The biologically active ingredients can be divided into 6 categories:polyphenols,polysaccharides,terpenoids,saponins,alkaloids,and others.The sources,models used for their study,efficacy,and mechanisms of action of food supplements are described.The sources,models used for their study,efficacy,and mechanisms of action of food supplements are described,including regulation of microflora,modulation of glucose metabolism,and improvement in insulin function.By classifying medicinal plants that can be used as food supplements and their activities,we have provided useful information to support further investigation and application of food supplements to prevent or improve diabetes mellitus. | Xiangxi Meng Qinyu Li Ruyu Shi Jiayin Chang Hong Chang Minhui Li | 2021 | Journal of Future Foods2021，1，1： | 0 |
| 8 | CorelKit:An Extensible CorelDraw VBA Program for Geoscience Drawing显示文摘CorelKit is developed with the built-in VBA environment of CorelDraw?,and is a new plug-in in CorelDraw for geological and geochemical drawing.CorelKit can help users quickly and easily draw geological and geochemical graphs,such as scatterplot,triangular scatterplot,line chart,histogram,bar chart,box plot,pie graph,etc.In order to adapt to the geological application,the above functions are strengthened.Scatterplot and triangular scatterplot provide nearly 150 common basemaps,covering rock classification,structural environment discrimination,mineral genesis,isotope geochemistry,etc.,for the convenience of the user mapping.Meanwhile,CorelKit further provides a structural joint rose diagram and sulfur isotopic composition diagram.This software also has many practical functions such as Bézier line topology,Multiple Bézier lines close fill,Single inner fill,Correction basemap,Add a compass,Add a scale,which facilitates daily geological drawing.The software has a friendly interface,in both Chinese and English versions,and is suitable for CorelDraw X4 and later versions.We introduced the Bézier line topology to CorelKit for the first time,which is similar to the GIS®topology for geological maps.According to the“GB/T 958-2015 Geological Legends Used for Regional Geological Map”,a two-color filling library of rock pattern pictures is established,which is convenient to realize the twocolor filling of sedimentary rocks,metamorphic rocks and magmatic rocks patterns.Obviously,CorelKit makes up for many shortcomings of CorelDraw in geosciences and is a very practical tool for geoscience researchers. | Junwu Zhang Xian Liang Fangyue Wang Huaikun Wang Yu Fan Te Ba Xiangxi Meng | 2023 | Journal of Earth Science2023，34，3： | 0 |
| 9 | An overview of the research undertakings of the development of China's archives informatization from 1997 to 2007显示文摘This paper makes a comprehensive statistical analysis of the papers published in recent years on the development of China’s archives informatization from the aspects of the quantity,research focuses and approaches and thematic contents.In addition,it summarizes the current research situation in this field in general. | CHEN Zhonghai MENG Xiangxi | 2009 | Chinese Journal of Library and Information Science2009，，2： | 0 |
| 10 | Synthesis and in-situ noble metal modification of WO3·0.33H2O nanorods from a tungsten-containing mineral for enhancing NH3 sensing performance显示文摘Ag-and Pt-doped WO3-0.33 H2O nanorods with high response and selectivity to NH3 were synthesized from a tungsten-containing mine ral of scheelite concentrate by a simple combined process,namely by a high pressure leaching method to obtain tungstate ions-containing leaching solution and followed by a hydrothermal method to prepare corresponding nanorods.The microstructure and NH3 sensing perfo rmance of the final products were investigated systematically.The microstructure characte rization showed that the as-prepared WO3-0.33 H2 O nanorods had a hexagonal crystal structure,and Ag and Pt nanoparticles were uniformly distributed in the WO3-0.33 H2O nano rods.Gas sensing measurements indicated that Ag and Pt nanopa rticles not only could obviously enhance NH3 sensing properties in terms of response,selectivity as well as response/recovery time,but also could reduce the optimal operating temperature at which the highest response was achieved.The highest responses of 22.4 and 47.6 for Agand Pt-doped WO3-0.33 H2O nanorods to 1000 ppm NH3 were obtained at 225 and 175℃,respectively,which were about four and eight folds higher than that of pure one at 250℃.The superior NH3 sensing properties are mainly ascribed to the catalytic activities of noble metals and the different work functions between noble metals and WO3-0.33 H2 O. | Tingting Li Yanbai Shen Sikai Zhao Pengfei Zhou Xiangxi Zhong Shuling Gao Dezhou Wei Fanli Meng | 2020 | Chinese Chemical Letters2020，31，8： | 0 |
| 11 | Simulation and quantitative analysis of fluorescence intensity distribution based on the Monte Carlo method显示文摘The Monte Carlo method is a versatile simulation algorithm to model the propagation of photons inside the biological tissues.It has been applied to the reconstruction of the fluorescence molecular tomography(FMT).However,such method suffers from low computational efficiency,and the time consumption is not desirable.One way to solve this problem is to introduce a priori knowledge which will facilitate iterative convergence.We presented an in vivo simulation environment for°uorescence molecular tomography(ISEFMT)using the Monte Carlo method to simulate the photon distribution of fluorescent objects and their sectional view in any direction quantitatively.A series of simulation experiments were carried out on different phantoms each with two fluorescent volumes to investigate the relationship among fluorescence intensity distribution and the excitation photon number,the locations and sizes of the fluorescence volumes,and the anisotropy coefficient.A significant principle was discovered,that along the direction of the excitation light,the fluorescent volume near the excitation point will provide shelter effect so that the energy of the fluorescent volume farther away from the excitation point is relatively lower.Through quantitative analysis,it was discovered that both the photon energy distribution on every cross section and the fluorescence intensity distributed in the two volumes exhibit exponential relationships.The two maximum positions in this distribution correspond to the centers of fluorescent volumes.Finally,we also explored the effect of the phantom coefficients on the exponential rule,and found out that the exponential rule still exists,only the coefficient of the exponential rule changed.Such results can be utilized in locating the positions of multiple fluorescent volumes in complicated FMT reconstruction involving multiple fluorescent volumes.Thus,a priori knowledge can be generalized,which would accelerate the reconstruction of FMT and even other images. | Kun Zhou Jian Tian Qiushi Zhang Xiangxi Meng Kun Yang Qiushi Ren | 2015 | Journal of Innovative Optical Health Sciences2015，8，6： | 0 |
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