231 results on '"Zhanhong Ma"'
Search Results
152. Hardness of metallic crystals
- Author
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K. E. Cao, Baohong Tian, Fengzhang Ren, Zhanhong Ma, Li Wuhui, and Juanhua Su
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Electron density ,Materials science ,Condensed matter physics ,Radius ,Nanocrystalline material ,Grain size ,Shear modulus ,Metal ,Crystallography ,Mechanics of Materials ,visual_art ,Atom ,visual_art.visual_art_medium ,General Materials Science ,Dislocation - Abstract
This paper presents a new formula for calculating the hardness of metallic crystals, resulted from the research on the critical grain size with stable dislocations. The formula is H = 6 kG/[pi(1 - nu)e(eta)], where H is the hardness, k the coefficient, G the shear modulus, nu the Poisson's ratio, eta a function of the radius of an atom (r) and the electron density at the atom interface (n). The formula will not only be used to testify the critical grain size with stable dislocations, but also play an important role in the understanding of mechanical properties of nanocrystalline metals.
- Published
- 2011
153. Chemical Composition of the Fruit Essential Oil ofPhellodendron chinense(Rutaceae) from China and Its Antifungal Activity against Plant Pathogenic Fungi
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Xiaolin Li, Zhanhong Ma, Ze-jian Guo, Jingguo Wang, X. Shi, Ligang Zhou, Mingan Wang, and Youwen Gong
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biology ,General Chemistry ,biology.organism_classification ,Antimicrobial ,Plant disease ,law.invention ,chemistry.chemical_compound ,Horticulture ,Rutaceae ,chemistry ,law ,Myrcene ,Botany ,Spore germination ,Phellodendron chinense ,Essential oil ,Mycelium - Abstract
Essential oil of Phellodendron chinense fruit was obtained by hydrodistillation and analyzed by GC-FID and GC-MS. Myrcene (70.7%), β-elemene (4.7%) and p-cymene (4.4%) were the major compounds of the 20 identified components. The antifungal activity of the oil, evaluated against fifteen plant pathogenic fungi, was determined by mycelial radial growth inhibition method. The values of the mean inhibitory concentration (IC50) against the tested fungi were at a range of 0.24–1.46 mg/mL. Furthermore, IC50 of the oil against spore germination of Magnaporthe oryzae was determined to be 2.60 mg/mL. These results indicated that P. chinense oil could be a potential source of antimicrobial ingredients for plant disease control.
- Published
- 2011
154. Analysis of population structure of Puccinia striiformis in Yunnan Province of China by using AFLP
- Author
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Xiufeng Liu, Zhenyu Sun, Chong Huang, Zhanhong Ma, Junmin Liang, and Yong Luo
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Veterinary medicine ,education.field_of_study ,Molecular epidemiology ,Wheat diseases ,Population ,food and beverages ,Population genetics ,Plant Science ,Horticulture ,Biology ,parasitic diseases ,Genotype ,Botany ,Puccinia striiformis ,Amplified fragment length polymorphism ,China ,education ,Agronomy and Crop Science ,geographic locations - Abstract
Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most destructive wheat diseases in China. Yunnan Province, located in south-western China, possesses unique features of geography, climate, wheat growth and stripe rust epidemics, different from main epidemic regions in China. The isolates of this pathogen were collected from nine counties in Yunnan Province during February to May of 2008. Used as a comparison, isolates were also collected from five counties of Gansu Province, the province important in inter-regional stripe rust epidemics in China. Amplified fragment length polymorphism (AFLP) method was applied to study the population genetics of the pathogen among different populations in these two provinces. Forty one AFLP genotypes were obtained from 150 isolates and the genotype qj3 showed the highest frequency in Yunnan Province. While 22 genotypes were detected from 40 isolates, no genotype showing as predominant was identified in Gansu Province. Genotypic diversity in Gansu Province was higher than that in Yunnan Province. A free recombination signature was detected in Gansu Province but not in Yunnan Province. We concluded that the population of P. striiformis in Yunnan Province can be considered as a clonal population.
- Published
- 2010
155. Occurrence of Puccinia polysora Causing Southern Corn Rust in the Northeast Huanghuaihai Region of China
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Zhanhong Ma, X. F. Liu, Yilin Gu, Q. Y. Sun, W. Y. Yuan, and J. Y. Xu
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Agronomy ,Plant Science ,Puccinia polysora ,Biology ,China ,Agronomy and Crop Science ,Rust - Published
- 2018
156. Effects of Fe2O3 concentration on microstructures and properties of SiC-based ceramic foams
- Author
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Zhanhong Ma, Limei Wang, Fengjun Li, Fengzhang Ren, Juanhua Su, and Zhe Wang
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Ceramic foam ,Materials science ,Scanning electron microscope ,Mechanical Engineering ,Energy-dispersive X-ray spectroscopy ,Sintering ,Mineralogy ,Condensed Matter Physics ,Microstructure ,chemistry.chemical_compound ,Compressive strength ,chemistry ,Mechanics of Materials ,visual_art ,visual_art.visual_art_medium ,Silicon carbide ,General Materials Science ,Ceramic ,Composite material - Abstract
Polyurethane foams were used as carriers to fabricate SiC-based ceramic foams. The compressive strength and thermal shock-resistance of SiC-based ceramic foams were investigated with concentration of Fe 2 O 3 . Using scanning electron microscopy and energy dispersive spectroscopy, the microstructure and composition of SiC-based ceramic foams in micro-scale were observed. It is found that when the concentration of Fe 2 O 3 increases, the number of cyclic thermal shock of the ceramic foams decreases obviously, and its compressive strength at room temperature increases rapidly. The concentration of Fe 2 O 3 pays an important rule for the sinter behavior of the SiC-based ceramic foams. Superfluous Fe 2 O 3 causes the formation of excessive glass phase in the ceramic foams.
- Published
- 2009
157. Effect of inoculating addition on machinability of gray cast iron
- Author
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Fengjun Li, Weiming Liu, Zhanhong Ma, Baohong Tian, and Fengzhang Ren
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Materials science ,Geochemistry and Petrology ,Machinability ,Metallurgy ,Ultimate tensile strength ,engineering ,General Chemistry ,Cast iron ,engineering.material ,Composite material ,Indentation hardness ,Microbial inoculant - Abstract
Gray cast irons were inoculated with FeSi75+RE and FeSi75+Sr inoculants. The changes of apex angle of the drills before and after being used were used to evaluate machinability of gray cast irons. Effect of FeSi75+RE and FeSi75+Sr inoculants on mechanical properties, machinability and sensibility of gray cast iron used in cylinder block were investigated. Experimental results showed that gray cast iron treated with 60%FeSi75+40% RE inoculants exhibited tensile strength consistently at about 295 MPa along with good hardness and improved metallurgical quality. While gray cast iron inoculated with 20%FeSi75+80% Sr inoculants exhibited the best machinability, the lowest cross-section sensibility and the least microhardness difference. The tool flank wear of the drill increased correspondingly with the increase of the microhardness difference of the matrix, indicating the great effect of homogeneity of the matrix on the machinability of gray cast iron.
- Published
- 2009
158. Canopy Spectral Characterization of Wheat Stripe Rust in Latent Period
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Shuhe Wang, Yilin Gu, Zhanhong Ma, Cuicui Wang, and Qi Liu
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Canopy ,Training set ,Article Subject ,Wheat diseases ,Discriminant partial least squares ,Stripe rust ,Atomic and Molecular Physics, and Optics ,Analytical Chemistry ,Statistics ,Puccinia striiformis ,lcsh:QC350-467 ,Spectral data ,Spectroscopy ,lcsh:Optics. Light ,Remote sensing ,Urediniospore ,Mathematics - Abstract
Stripe rust, caused byPuccinia striiformisf. sp.tritici(Pst), is one of the important wheat diseases worldwide. In this study, the spectral data were collected from wheat canopy during the latent period inoculated with three different concentrations of urediniospores and classification models based on discriminant partial least squares (DPLS) were built to differentiate leaves with and without infection of the stripe rust pathogen. The effects of different spectra features, wavebands, and the number of the samples used in modeling on the performances of the models were assessed. The results showed that, in the spectral region of 325–1075 nm, the model with the spectral feature of 2nd derivative of Pseudoabsorption index had better accuracy than others. The average accuracy rate was 97.28% for the training set and 92.98% for the testing set. In the waveband of 925–1075 nm, the model with the spectral feature of 1st derivative Pseudoabsorption index had better accuracy than other models, and the average accuracy rates were 98.27% and 94.33% for the training and testing sets, respectively. The results demonstrated that wheat stripe rust in latent period can be qualitatively identified based on the canopy spectral detection. Thus, the method can be used for early monitoring of infections of wheat stripe rust.
- Published
- 2015
- Full Text
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159. Quantitative Determination of Germinability of Puccinia striiformis f. sp. tritici Urediospores Using Near Infrared Spectroscopy Technology
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Long-Lian Zhao, Jun-hui Li, Pei Cheng, Xiaolong Li, Zhanhong Ma, Haiguang Wang, Feng Qin, and Yaqiong Zhao
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Materials science ,Training set ,Article Subject ,Near-infrared spectroscopy ,Analytical chemistry ,Stripe rust ,Atomic and Molecular Physics, and Optics ,Quantitative determination ,Analytical Chemistry ,Partial least squares regression ,Spore germination ,lcsh:QC350-467 ,Puccinia striiformis ,Near infrared reflectance spectroscopy ,lcsh:Optics. Light ,Spectroscopy - Abstract
Stripe rust caused byPuccinia striiformisf. sp.tritici(Pst) is an important disease on wheat. In this study, quantitative determination of germinability ofPsturediospores was investigated by using near infrared reflectance spectroscopy (NIRS) combined with quantitative partial least squares (QPLS) and support vector regression (SVR). The near infrared spectra of the urediospore samples were acquired using FT-NIR MPA spectrometer and the germination rate of each sample was measured using traditional spore germination method. The best QPLS model was obtained with vector correction as the preprocessing method of the original spectra and 4000–12000 cm−1as the modeling spectral region while the modeling ratio of the training set to the testing set was 4 : 1. The best SVR model was built when vector normalization was used as the preprocessing method, the modeling ratio was 5 : 1 and the modeling spectral region was 8000–11000 cm−1. The results showed that the effect of the best model built using QPLS or SVR was satisfactory. This indicated that quantitative determination of germinability ofPsturediospores using near infrared spectroscopy technology is feasible. A new method based on NIRS was provided for rapid, automatic, and nondestructive determination of germinability ofPsturediospores.
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- 2015
- Full Text
- View/download PDF
160. Identification and Disease Index Inversion of Wheat Stripe Rust and Wheat Leaf Rust Based on Hyperspectral Data at Canopy Level
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Qi Liu, Pei Cheng, Hui Wang, Rui Wang, Xiaolong Li, Zhanhong Ma, Feng Qin, Liu Ruan, and Haiguang Wang
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Canopy ,Article Subject ,biology ,Wheat diseases ,0211 other engineering and technologies ,Hyperspectral imaging ,Inversion (meteorology) ,04 agricultural and veterinary sciences ,02 engineering and technology ,biology.organism_classification ,Atomic and Molecular Physics, and Optics ,Analytical Chemistry ,Wavelet packet decomposition ,Support vector machine ,Wheat leaf rust ,Statistics ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,lcsh:QC350-467 ,Data pre-processing ,Spectroscopy ,lcsh:Optics. Light ,021101 geological & geomatics engineering ,Mathematics - Abstract
Stripe rust and leaf rust with similar symptoms are two important wheat diseases. In this study, to investigate a method to identify and assess the two diseases, the canopy hyperspectral data of healthy wheat, wheat in incubation period, and wheat in diseased period of the diseases were collected, respectively. After data preprocessing, three support vector machine (SVM) models for disease identification and six support vector regression (SVR) models for disease index (DI) inversion were built. The results showed that the SVM model based on wavelet packet decomposition coefficients with the overall identification accuracy of the training set equal to 99.67% and that of the testing set equal to 82.00% was better than the other two models. To improve the identification accuracy, it was suggested that a combination model could be constructed with one SVM model and two models built usingK-nearest neighbors (KNN) method. Using the DI inversion SVR models, the satisfactory results were obtained for the two diseases. The results demonstrated that identification and DI inversion of stripe rust and leaf rust can be implemented based on hyperspectral data at the canopy level.
- Published
- 2015
161. Rapid and Precise Detection of Latent Infections of Wheat Stripe Rust in Wheat Leaves using Loop-Mediated Isothermal Amplification
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Haiguang Wang, Zhenyu Sun, Jiahui Yan, Zhanhong Ma, Yong Luo, and Chong Huang
- Subjects
Molecular epidemiology ,Physiology ,Inoculation ,Loop-mediated isothermal amplification ,food and beverages ,Stripe rust ,Plant Science ,Biology ,Virology ,Spore ,chemistry.chemical_compound ,chemistry ,Botany ,Genotype ,Genetics ,Poaceae ,Agronomy and Crop Science ,DNA - Abstract
Wheat stripe rust caused by Puccinia striiformis f.sp. tritici (Pst) is one of the most important diseases of wheat worldwide. Detection of latent infection in leaves is critical for estimating the initial inoculum potential of epidemics. A loop-mediated isothermal amplification (LAMP) assay was developed and evaluated for the detection of Pst DNA in spores and wheat seedlings with latent infections. LAMP assay could detect as low as 2 pg/μl template DNA and detect latent infections from leaves as early as 24 h after inoculation. This provides a rapid and accurate method of estimating latent infection levels.
- Published
- 2011
162. Multiple displacement amplification of whole genomic DNA from urediospores of Puccinia striiformis f. sp. tritici
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B. M. Wu, R. Zhang, and Zhanhong Ma
- Subjects
Genetics ,Amplified Fragment Length Polymorphism Analysis ,Basidiomycota ,Multiple displacement amplification ,Fungal genetics ,food and beverages ,General Medicine ,Nucleic acid amplification technique ,Genomics ,Biology ,Real-Time Polymerase Chain Reaction ,Molecular biology ,DNA extraction ,chemistry.chemical_compound ,genomic DNA ,chemistry ,Amplified fragment length polymorphism ,Genome, Fungal ,DNA, Fungal ,Nucleic Acid Amplification Techniques ,DNA ,Triticum - Abstract
Biotrophic fungi, such as Puccinia striiformis f. sp. tritici, because they cannot be cultured on nutrient media, to obtain adequate quantity of DNA for molecular genetic analysis, are usually propagated on living hosts, wheat plants in case of P. striiformis f. sp. tritici. The propagation process is time-, space- and labor-consuming and has been a bottleneck to molecular genetic analysis of this pathogen. In this study we evaluated multiple displacement amplification (MDA) of pathogen genomic DNA from urediospores as an alternative approach to traditional propagation of urediospores followed by DNA extraction. The quantities of pathogen genomic DNA in the products were further determined via real-time PCR with a pair of primers specific for the β-tubulin gene of P. striiformis f. sp. tritici. The amplified fragment length polymorphism (AFLP) fingerprints were also compared between the DNA products. The results demonstrated that adequate genomic DNA at fragment size larger than 23 Kb could be amplified from 20 to 30 urediospores via MDA method. The real-time PCR results suggested that although fresh urediospores collected from diseased leaves were the best, spores picked from diseased leaves stored for a prolonged period could also be used for amplification. AFLP fingerprints exhibited no significant differences between amplified DNA and DNA extracted with CTAB method, suggesting amplified DNA can represent the pathogen’s genomic DNA very well. Therefore, MDA could be used to obtain genomic DNA from small precious samples (dozens of spores) for molecular genetic analysis of wheat stripe rust pathogen, and other fungi that are difficult to propagate.
- Published
- 2014
163. Pulmonary involvement in patients with Behçet's disease: report of 15 cases
- Author
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Xiaolei, Zhang, Huaping, Dai, Zhanhong, Ma, Yuanhua, Yang, and Yan, Liu
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Adult ,Lung Diseases ,Male ,Young Adult ,Behcet Syndrome ,Humans ,Female ,Middle Aged ,Pulmonary Artery ,Tomography, X-Ray Computed ,Retrospective Studies - Abstract
Behçet's disease (BD) is a multisystem vasculitis, and pulmonary involvement in BD can have complex clinical manifestations. We aimed to analyze the clinical and radiological features, as well as the outcomes, of BD patients with pulmonary manifestation.We retrospectively reviewed the medical records of 106 patients with BD diagnosed in our institute between January 2000 and January 2013. Patients with pulmonary vascular or parenchymal abnormalities on chest radiography, thorax computed tomography, magnetic resonance imaging or pulmonary scintigraphy were included in this study.Fifteen patients (14%) were identified to have pulmonary involvement. Pulmonary artery aneurysms (PAA) was observed in six patients, and all of them had concomitant thrombi, attenuation or occlusion of PAs, and five of them also had radiographic parenchymal changes. Three patients had solely pulmonary artery thrombus (PAT) without PAA. For the six patients with isolated radiographic parenchyma changes, pulmonary infiltration resolved with immunosuppressant therapy in four subjects; the lesion remained unchanged in one subject with radiographic interstitial changes, and acid-fast bacilli were found in the remaining subject. Patients with PAA or PAT had more frequency of hemoptysis and extra-pulmonary vascular lesions compared with isolated parenchymal involvement. Radiographic parenchyma changes are nonspecific, with ill-defined ground-glass opacity being the most common pulmonary radiographic parenchymal changes. Patients with isolated parenchymal changes had better prognosis than those with PAA or PAT.BD with pulmonary involvement can have a wide spectrum of abnormal clinical and radiographic manifestations, and multiple pulmonary lesions can exit in the same patient.
- Published
- 2014
164. Nanometer-scale regular grooves and ridges created with scanning tunnelling microscope
- Author
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Dongxia Shi, Haiqiang Yang, Ning Liu, Yunlong Jiang, Zhanhong Ma, Z. Q. Xue, S.J. Pang, and J.N Gao
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geography ,geography.geographical_feature_category ,Microscope ,Morphology (linguistics) ,Silicon ,business.industry ,Chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,Surfaces, Coatings and Films ,law.invention ,Optics ,Ridge ,law ,Optoelectronics ,Nanometre ,business ,Groove (music) ,Deposition (law) ,Quantum tunnelling - Abstract
The scanning tunnelling microscope (STM) has been employed to fabricate grooves by extracting Si atoms out of the Si(111)-7×7 surface and deposit the Si atoms back onto the Si(111)-7×7 surface at room temperature. The deposited Si atoms can form a straight ridge under controlled conditions. The width of the ridge can be controlled better than 2 nm. Ridges can only be formed after the tip extracts enough atoms out of the Si(111)-7×7 surface. If the tip is clean, no atoms will be deposited from the tip under the depositing conditions. This suggests that the deposited atoms are silicon atoms extracted out of the Si(111)-7×7 surface. The deposition mechanism is discussed.
- Published
- 1998
165. Development of a Web-Based Prediction System for Wheat Stripe Rust
- Author
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Wancai Liu, Zhanhong Ma, Haiguang Wang, and Weigang Kuang
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Computer science ,business.industry ,Sql server ,Web application ,Regression analysis ,Stripe rust ,Data mining ,Prediction system ,computer.software_genre ,business ,computer ,Predictive modelling - Abstract
A web-based prediction system for wheat stripe rust was developed based on B/S (Browser/Server) mode in this study. Some existing prediction models of wheat stripe rust were collected, analyzed and then stored in SQL Server 2005 database according to certain rules. All these models could be called through this web-based system and used to predict wheat stripe rust. Meanwhile, Using multiple regression analysis principle, prediction regression model could be built based on the input historical data of wheat stripe rust through the network programming via this system, and significance tests of prediction factors could be conducted to obtain optimal prediction model and the built model could be stored into the model database for further prediction of this disease. Using WebGIS technologies, the prediction results of wheat stripe rust could be displayed in different colors in the web map according to the prediction values of disease prevalence. The web-based prediction system for wheat stripe rust developed in this study provided a convenient and fast way for the prediction of wheat stripe rust.
- Published
- 2013
166. Development of a Single-Leaf Disease Severity Automatic Grading System Based on Image Processing
- Author
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Haiguang Wang, Zhanhong Ma, and Guanlin Li
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Computer science ,business.industry ,media_common.quotation_subject ,Image processing ,Pattern recognition ,Adaptability ,Plant disease ,Disease severity ,Leaf disease ,Segmentation ,Artificial intelligence ,MATLAB ,business ,Grading (education) ,computer ,computer.programming_language ,media_common - Abstract
In order to realize accurately calculating and automatically grading of plant disease severity, a single-leaf disease severity automatic grading system based on image processing was developed by using MATLAB GUIDE platform. Using this system, the single-leaf disease severity could be automatically assessed and graded via image development technologies including segmentation processing technologies of plant disease images and related data mining technologies. Structural diagram of the system, algorithms used in the system and realization of the system functions were described. The problems in the current version of the system were discussed and further research on this subject was suggested. The usefulness and adaptability of the system was evaluated using the images of grape downy mildew caused by Plasmopara viticola. The results showed that the effectiveness of the system was favorable with high accuracy.
- Published
- 2012
167. Image recognition of plant diseases based on backpropagation networks
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Xiaolong Li, Haiguang Wang, Guanlin Li, and Zhanhong Ma
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business.industry ,Wheat diseases ,Feature extraction ,Pattern recognition ,Image processing ,Image segmentation ,Image texture ,Pattern recognition (psychology) ,Computer vision ,Artificial intelligence ,business ,Cluster analysis ,Mathematics ,Image compression - Abstract
To achieve automatic diagnosis of plant diseases and improve the image recognition accuracy of plant diseases, two kinds of grape diseases (grape downy mildew and grape powdery mildew) and two kinds of wheat diseases (wheat stripe rust and wheat leaf rust) were selected as research objects, and the image recognition of the diseases was conducted based on image processing and pattern recognition. After image preprocessing including image compression, image cropping and image denoising, K_means clustering algorithm was used to segment the disease images, and then 21 color features, 4 shape features and 25 texture features were extracted from the images. Backpropagation (BP) networks were used as the classifiers to identify grape diseases and wheat diseases, respectively. The results showed that identification of the diseases could be effectively achieved using BP networks. While the dimensions of the feature data were not reduced by using principal component analysis (PCA), the optimal recognition results for grape diseases were obtained as the fitting accuracy and the prediction accuracy were both 100%, and that for wheat diseases were obtained as the fitting accuracy and the prediction accuracy were both 100%. While the dimensions of the feature data were reduced by using PCA, the optimal recognition result for grape diseases was obtained as the fitting accuracy was 100% and the prediction accuracy was 97.14%, and that for wheat diseases was obtained as the fitting accuracy and the prediction accuracy were both 100%.
- Published
- 2012
168. Identification and Severity Determination of Wheat Stripe Rust and Wheat Leaf Rust Based on Hyperspectral Data Acquired Using a Black-Paper-Based Measuring Method
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Qi Liu, Haiguang Wang, Pei Cheng, Liu Ruan, Xiaolong Li, Rui Wang, Feng Qin, Zhanhong Ma, and Hui Wang
- Subjects
0106 biological sciences ,Leaves ,Support Vector Machine ,Light ,lcsh:Medicine ,Plant Science ,01 natural sciences ,Rust ,Remote Sensing ,Machine Learning ,Partial least squares regression ,Statistics ,lcsh:Science ,Triticum ,Multidisciplinary ,biology ,Plant Anatomy ,Physics ,Electromagnetic Radiation ,Plant Fungal Pathogens ,food and beverages ,Hyperspectral imaging ,Agriculture ,04 agricultural and veterinary sciences ,Plants ,Data Acquisition ,Spectrophotometry ,Wheat ,Physical Sciences ,Engineering and Technology ,Research Article ,Paper ,Computer and Information Sciences ,China ,Mean squared error ,Plant Pathogens ,Crops ,Wheat Stripe Rust ,Cross-validation ,Wheat leaf rust ,Artificial Intelligence ,Support Vector Machines ,Grasses ,Least-Squares Analysis ,Plant Diseases ,Basidiomycota ,lcsh:R ,Organisms ,Biology and Life Sciences ,Plant Pathology ,biology.organism_classification ,Plant Leaves ,Support vector machine ,Agronomy ,Remote Sensing Technology ,040103 agronomy & agriculture ,Cognitive Science ,0401 agriculture, forestry, and fisheries ,lcsh:Q ,Data pre-processing ,Crop Science ,Cereal Crops ,Neuroscience ,010606 plant biology & botany - Abstract
It is important to implement detection and assessment of plant diseases based on remotely sensed data for disease monitoring and control. Hyperspectral data of healthy leaves, leaves in incubation period and leaves in diseased period of wheat stripe rust and wheat leaf rust were collected under in-field conditions using a black-paper-based measuring method developed in this study. After data preprocessing, the models to identify the diseases were built using distinguished partial least squares (DPLS) and support vector machine (SVM), and the disease severity inversion models of stripe rust and the disease severity inversion models of leaf rust were built using quantitative partial least squares (QPLS) and support vector regression (SVR). All the models were validated by using leave-one-out cross validation and external validation. The diseases could be discriminated using both distinguished partial least squares and support vector machine with the accuracies of more than 99%. For each wheat rust, disease severity levels were accurately retrieved using both the optimal QPLS models and the optimal SVR models with the coefficients of determination (R2) of more than 0.90 and the root mean square errors (RMSE) of less than 0.15. The results demonstrated that identification and severity evaluation of stripe rust and leaf rust at the leaf level could be implemented based on the hyperspectral data acquired using the developed method. A scientific basis was provided for implementing disease monitoring by using aerial and space remote sensing technologies.
- Published
- 2016
169. Application of neural networks to image recognition of plant diseases
- Author
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Guanlin Li, Haiguang Wang, Xiaolong Li, and Zhanhong Ma
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Engineering ,Artificial neural network ,business.industry ,Wheat diseases ,Feature extraction ,Probabilistic logic ,Image processing ,Machine learning ,computer.software_genre ,Backpropagation ,Digital image ,Radial basis function ,Computer vision ,Artificial intelligence ,business ,computer - Abstract
Digital image recognition of plant diseases could reduce the dependence of agricultural production on the professional and technical personnel in plant protection field and is conducive to the development of plant protection informatization. In order to find out a method to realize image recognition of plant diseases, four kinds of neural networks including backpropagation (BP) networks, radial basis function (RBF) neural networks, generalized regression networks (GRNNs) and probabilistic neural networks (PNNs) were used to distinguish wheat stripe rust from wheat leaf rust and to distinguish grape downy mildew from grape powdery mildew based on color features, shape features and texture features extracted from the disease images. The results showed that identification and diagnosis of the plant diseases could be effectively achieved using BP networks, RBF neural networks, GRNNs and PNNs based on image processing. For the two kinds of wheat diseases, the best prediction accuracy was 100% with the fitting accuracy equal to 100% while BP networks, GRNNs or PNNs were used, and the best prediction accuracy was 97.50% with the fitting accuracy equal to 100% while RBF neural networks were used. For the two kinds of grape diseases, the best prediction accuracy was 100% with the fitting accuracy equal to 100% while BP networks, GRNNs or PNNs were used, and the best prediction accuracy was 94.29% with the fitting accuracy equal to 100% while RBF neural networks were used.
- Published
- 2012
170. Image recognition of plant diseases based on principal component analysis and neural networks
- Author
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Guanlin Li, Zhanhong Ma, Haiguang Wang, and Xiaolong Li
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biology ,Contextual image classification ,Artificial neural network ,business.industry ,Computer science ,Wheat diseases ,Feature extraction ,Stripe rust ,Pattern recognition ,Machine learning ,computer.software_genre ,biology.organism_classification ,Backpropagation ,Plant disease ,Wheat leaf rust ,Image texture ,Principal component analysis ,Downy mildew ,Computer vision ,Artificial intelligence ,business ,computer ,Powdery mildew - Abstract
Plant disease identification based on image processing could quickly and accurately provide useful information for the prediction and control of plant diseases. In this study, 21 color features, 4 shape features and 25 texture features were extracted from the images of two kinds wheat diseases (wheat stripe rust and wheat leaf rust) and two kinds of grape diseases (grape downy mildew and grape powdery mildew), principal component analysis (PCA) was performed for reducing dimensions in feature data processing, and then neural networks including backpropagation (BP) networks, radial basis function (RBF) neural networks, generalized regression networks (GRNNs) and probabilistic neural networks (PNNs) were used as the classifiers to identify wheat diseases and grape diseases, respectively. The results showed that these neural networks could be used for image recognition of these diseases based on reducing dimensions using PCA and acceptable fitting accuracies and prediction accuracies could be obtained. For the two kinds of wheat diseases, the optimal recognition result was obtained when image recognition was conducted based on PCA and BP networks, and the fitting accuracy and the prediction accuracy were both 100%. For the two kinds of grape diseases, the optimal recognition results were obtained when GRNNs and PNNs were used as the classifiers after reducing the dimensions of feature data with PCA, and the prediction accuracies were 94.29% with the fitting accuracies equal to 100%.
- Published
- 2012
171. Prediction of Wheat Stripe Rust Based on Neural Networks
- Author
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Haiguang Wang and Zhanhong Ma
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Artificial neural network ,Computer science ,business.industry ,Prediction methods ,Probabilistic logic ,Stability (learning theory) ,Stripe rust ,Artificial intelligence ,business ,Machine learning ,computer.software_genre ,computer ,Backpropagation - Abstract
Stripe rust caused byPuccinia striiformis f. sp.tritici, is a devastating wheat disease in the world. The prediction of this disease is very important to make control strategies. In order to figure out suitable prediction methods based on neural networks that could provide accurate prediction information with high stability, the predictions of wheat stripe rust by using backpropagation networks with different transfer functions, training functions and learning functions, radial basis networks, generalized regression networks (GRNNs) and probabilistic neural networks (PNNs) were conducted in this study. The results indicated that suitable backpropagation networks, radial basis networks and GRNNs could be used for the prediction of wheat stripe rust. Good fitting accuracy and prediction accuracy could be obtained by using backpropagation networks with trainlm, trainrp or trainbfg as training function. Radial basis networks had more power than backpropagation networks and GRNNs to predict wheat stripe rust. GRNNs were easier to be used than backpropagation networks. New methods based on neural networks were provided for the prediction of wheat stripe rust.
- Published
- 2012
172. Monitoring Wheat Stripe Rust Using Remote Sensing Technologies in China
- Author
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Zhanhong Ma, Haiguang Wang, and Jie-Bin Guo
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business.industry ,Remote sensing (archaeology) ,Global Positioning System ,Environmental science ,Stripe rust ,business ,Remote sensing - Abstract
Many studies on remote sensing monitoring of plant diseases have been conducted. Remote sensing (RS) has played an important role in monitoring some kinds of plant diseases and making decisions for the management of the diseases. Progress on remote sensing monitoring of wheat stripe rust in China was summarized from four aspects including remote sensing monitoring stripe rust of single wheat leaves and monitoring this disease using ground, aerial and space remote sensing technologies. The phenomena of same object with different spectra and different objects with same spectrum, the lowest threshold of disease prevalence for remote sensing monitoring, the spectral information distilling technologies, and the methods to develop inversion models based on spectral information were also discussed. Moreover, the development trends of multi-pest remote sensing, space remote sensing and integrated utilization of RS, geographical information system (GIS) and global positioning system (GPS) in monitoring wheat stripe rust were prospected.
- Published
- 2012
173. Image Recognition of Grape Downy Mildew and Grape Powdery Mildew Based on Support Vector Machine
- Author
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Guanlin Li, Haiguang Wang, and Zhanhong Ma
- Subjects
Support vector machine ,business.industry ,Computer science ,fungi ,food and beverages ,Downy mildew ,Unsupervised segmentation ,Computer vision ,Artificial intelligence ,business ,Cluster analysis ,Powdery mildew - Abstract
In order to realize automatic disease diagnosis and provide related information for disease prediction and control timely and accurately, the identification and diagnosis of grape downy mildew and grape powdery mildew was conducted based on image recognition technologies. The method based on K_means clustering algorithm was used to implement unsupervised segmentation of the disease images. Fifty shape, color and texture features were extracted from the images of the diseases. Support vector machine (SVM) classifier for the diseases was designed based on thirty-one effective selected features. The training recognition rates of these two kinds of grape diseases were both 100%, and the testing recognition rates of grape downy mildew and grape powdery mildew were 90% and 93.33%, respectively. The recognition results using the SVMs with different kernels indicated that the SVM with linear kernel was the most suitable for image recognition of the diseases. This study provided an effective way for rapid and accurate identification and diagnosis of plant diseases, and also provided a basis and reference for further development of automatic diagnosis system for plant diseases.
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- 2012
174. Technetium-99m-labelled HL91 and technetium-99m-labelled MIBI SPECT imaging for the detection of ischaemic viable myocardium: a preliminary study
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Min, Liu, Zhanhong, Ma, Xiaojuan, Guo, Jianguo, Zhu, and Jun, Su
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Male ,Technetium Tc 99m Sestamibi ,Tissue Survival ,Tomography, Emission-Computed, Single-Photon ,China ,Time Factors ,Myocardium ,Myocardial Ischemia ,Myocardial Perfusion Imaging ,Coronary Disease ,Pilot Projects ,Organotechnetium Compounds ,Middle Aged ,Predictive Value of Tests ,Coronary Circulation ,Oximes ,Humans ,Female ,Radiopharmaceuticals ,Aged - Abstract
The assessment of myocardial viability has become an important aspect of the diagnostic and prognostic work-up of patients with coronary artery disease. Technetium-99m labelled sestamibi ((99m)Tc-MIBI) myocardial perfusion imaging may underestimate the viability of ischaemic myocardium. Technetium-99m labelled 4,9-diaza-3,3,10,10-tetramethyldodecan-2,11-dione dioxime ((99m)Tc-HL91) is a hypoxia-avid agent which can identify acutely ischaemic viable myocardium in a canine model using a standard gamma camera. The aim of this study was to evaluate uptake character of ischaemic viable myocardium and diagnostic performance of single-photon emission computed tomography (SPECT) imaging by (99m)Tc-HL91 and (99m)Tc-MIBI in detecting ischaemic viable myocardium in coronary heart disease.A total of 41 patients with coronary artery disease were recruited from March 2008 to May 2009. For detecting ischaemic viable myocardium, SPECT imaging by (99m)Tc-HL91 and (99m)Tc-MIBI were performed in all patients before coronary revascularization. Six patients with single ischaemic myocardial segment received a 2-day SEPCT/CT imaging protocol and the uptake of (99m)Tc-HL91 in ischaemic myocardium was quantitatively analysed. The remaining 35 patients received a 1-day (99m)Tc-HL91 and (99m)Tc-MIBI SPECT imaging protocol. Resting (99m)Tc-MIBI myocardial perfusion imaging in 3-18 months after revascularization was used as the standard methodology to evaluate the myocardial viability.In 41 patients, 66 ischaemic myocardial segments were proven to be viable and 12 to be necrotic by resting (99m)Tc-MIBI myocardial perfusion imaging after coronary revascularization. Furthermore, 60 viable segments with negative uptake of (99m)Tc-MIBI showed positive uptake of (99m)Tc-HL91. The remaining six viable segments and 12 necrotic segments showed both negative uptake of (99m)Tc-HL91 and (99m)Tc-MIBI. The sensitivity, specificity, accuracy, Younden Index, positive predictive value and negative predictive value for evaluating ischaemic viable myocardium were 90·9%, 100%, 92·3%, 90·9%, 100% and 66·7%, respectively. Ischaemic viable myocardium had the negative (99m)Tc-MIBI uptake and positive (99m)Tc-HL91 uptake, which demonstrated a mismatched uptake character. Quantitative analysis indicated the uptake of (99m)Tc-HL91 in viable myocardium was increasing in the first 1-3 h and remained stable at the 3-4 h after injection.Functional SPECT imaging with (99m)Tc-HL91 and (99m)Tc-MIBI can be used to detect the seriously ischaemic but viable myocardium with a mismatched uptake character. The uptake of (99m)Tc-HL91 in the viable myocardium reached a stable level at 3-4 h after injection.
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- 2011
175. Cardiovascular parameters of computed tomographic pulmonary angiography to assess pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension
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Chen Wang, Xiang-yun Chen, Zhanhong Ma, Min Liu, Yuanhua Yang, and Xiaojuan Guo
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Male ,medicine.medical_specialty ,Pulmonary Circulation ,Adolescent ,Hypertension, Pulmonary ,Hemodynamics ,Sensitivity and Specificity ,Young Adult ,medicine.artery ,medicine ,Pulmonary angiography ,Humans ,Aged ,Retrospective Studies ,Aged, 80 and over ,Receiver operating characteristic ,Cobb angle ,business.industry ,Angiography ,Retrospective cohort study ,Stepwise regression ,Middle Aged ,eye diseases ,medicine.anatomical_structure ,ROC Curve ,Pulmonary artery ,Chronic Disease ,Vascular resistance ,Linear Models ,Female ,Vascular Resistance ,sense organs ,Radiology ,Cardiology and Cardiovascular Medicine ,business ,Pulmonary Embolism ,Tomography, X-Ray Computed - Abstract
Objectives The purpose is to identify the role of cardiovascular parameters of computed tomographic pulmonary angiography (CTPA) to assess pulmonary vascular resistance (PVR) in patients with chronic thromboembolic pulmonary hypertension (CTEPH). Background The assessment of PVR is of great importance in the management of patients with CTEPH. The role of CPTA in assessment of PVR of CTEPH remains to be explored. Methods Clinical and radiological data of 90 patients (55 men, age 17–84years) with CTEPH were retrospectively reviewed in this study. All patients received CTPA before right-heart catheterization. Cardiovascular parameters and Pulmonary Artery Obstruction Indices including Qanadli Index and Mastora Index were evaluated on CTPA. Hemodynamic PVR was calculated with the standard formula according to data from right-heart catheterization. The correlation of cardiovascular parameters of CTPA and PVR was analyzed. Results In Cardiovascular parameters, neither Qanadli Index(r=0.134, p=0.208) nor Mastora Index (r=0.149, p=0.90) did correlate with PVR. Cobb angle(r=0.613, p=0.000), the ratio of right to left ventricular area(r=0.422, p=0.000)and the ratio of right to left ventricular transverse diameter (r=0.410, p=0.000) respectively correlated with PVR. By receiver operating characteristic curve analysis, a Cobb angle cutoff value of 67.55° had a sensitivity of 72.5% and a specificity of 84.0% to determine PVR ≥1000 (dyn.sec/cm 5 ) and its Area Under Curve is (0.800±0.048). By stepwise linear regression analysis, Cobb angle was only one variable (R=0.601) shown to be independently associated with PVR, leading to the following equation: PVR=25.796×Cobb angle−585.935(F=37.929, p=0.000). Conclusion The analysis of CTPA-derived cardiovascular parameters, especially the Cobb angle, is a reliable tool for estimating PVR in patients with CTEPH, but Pulmonary Artery Obstruction Indices do not correlate with PVR.
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- 2011
176. Computed tomographic pulmonary angiography in the assessment of severity of chronic thromboembolic pulmonary hypertension and right ventricular dysfunction
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Xiaojuan Guo, Zhanhong Ma, Min Liu, Yuanhua Yang, Hongxia Zhang, and Chen Wang
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Adult ,Male ,medicine.medical_specialty ,Adolescent ,Hypertension, Pulmonary ,Ventricular Dysfunction, Right ,Hemodynamics ,Sensitivity and Specificity ,Severity of Illness Index ,Computed tomographic ,Young Adult ,Internal medicine ,medicine.artery ,Pulmonary angiography ,Medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Respiratory system ,Aged ,Aged, 80 and over ,business.industry ,Angiography ,Reproducibility of Results ,General Medicine ,Middle Aged ,medicine.disease ,Pulmonary hypertension ,Right ventricular dysfunction ,Pulmonary artery ,Chronic Disease ,Cardiology ,Radiographic Image Interpretation, Computer-Assisted ,Chronic thromboembolic pulmonary hypertension ,Female ,business ,Pulmonary Embolism ,Tomography, X-Ray Computed - Abstract
Purpose The aim was to investigate the role of computed tomographic pulmonary angiography (CTPA) in the assessment of severity and right ventricular function in chronic thromboembolic pulmonary hypertension (CTEPH). Materials and methods Clinical and radiological data of 56 patients with CTEPH January 2006–October 2009 were retrospectively reviewed in the present study. All patients received CTPA with a 64-row CT using the retrospective ECG-Gated mode before digital subtraction pulmonary angiography and right-heart catheterization. CTPA findings including Right Ventricular diameter (RVd) and left ventricular diameter (LVd) were measured at the end diastole. CT Pulmonary Artery Obstruction Indexes including Qanadli Index and Mastora Index were used in the assessment of severity of pulmonary arterial obstruction. Hemodynamic parameters and pulmonary hypertension classification were evaluated by right-heart catheterization in all patients. Right ventricular function was measured with echocardiography in 49 patients. Results Qanadli Index and Mastora Index respectively were (37.93±14.74)% and (30.92±16.91)%, which showed a significant difference ( Z =−5.983, P =0.000) and a good correlation ( r =0.881, P =0.000). Neither Qanadli nor Mastora Index correlated with pulmonary hypertension classification ( r =−0.009, P =0.920) or New York Heart Association heart function classification ( r =−0.031, P =0.756). Neither Qanadli nor Mastora Index correlated with any echocardiographic right ventricular parameters ( P >0.05), while RVd/LVd by CTPA correlated with echocardiographic right ventricular functional parameters ( P r =−0.288, P =0.006) and Mastora Index ( r =−0.203, P =0.032) demonstrated a weakly negative correlation with SPO 2 . CTPA findings correlated with hemodynamic variables. Backward linear regression analysis revealed that the RVd/LVd, Right Ventricular Anterior Wall Thickness (RVAWT), Main Pulmonary Artery trunk diameter (MPAd) were shown to be independently associated with mean Pulmonary Artery Pressure (mPAP) levels (model: r 2 =0.351, P =0.025; RVd/LVd: beta=11.812, P =0.000; RVAWT: beta=2.426, P =0.000; MPAd: beta=0.677, P =0.003). Conclusion Computed tomographic pulmonary angiography is a valuable tool to evaluate hemodynamics, right ventricular function of CTEPH, but neither Qanadli Index nor Mastora Index can reflect pulmonary arterial obstruction in CTEPH accurately.
- Published
- 2010
177. Investigation of periodic structures of polyethylene crystal lamellas with STM
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Zhanhong Ma, Z.Q. Xue, W.M. Liu, Hongyi Gao, S. J. Pang, and Congshan Zhu
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Plane parallel ,Materials science ,General Physics and Astronomy ,Surfaces and Interfaces ,General Chemistry ,Polyethylene ,Condensed Matter Physics ,Surfaces, Coatings and Films ,law.invention ,Crystallography ,chemistry.chemical_compound ,chemistry ,Transmission electron microscopy ,law ,Ionization ,Lamellar structure ,Scanning tunneling microscope ,Thin film - Abstract
We have prepared polyethylene thin films with the ionized cluster beam (ICB) deposition technique. There are perfect polyethylene crystal lamellas in the thin films. We have observed the polyethylene lamellar surface topography with scanning tunneling microscopy (STM), and found the fold chain structures on the (001) surface of polyethylene crystal lamellas first. We have analyzed polyethylene thin films with transmission electron microscopy (TEM) and found the (001) plane parallel to the surface of the substrate. There are strict periodic structures in the (110) plane, but no good periodic structures in the [110] direction.
- Published
- 1992
178. Isoquinoline alkaloids from Macleaya cordata active against plant microbial pathogens
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Weibo Jiang, Jihua Wang, Zhanhong Ma, Jingguo Wang, Hao Liu, Ligang Zhou, Jianglin Zhao, and Shiqiong Lu
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Magnetic Resonance Spectroscopy ,Plant Science ,Microbial Sensitivity Tests ,Mass Spectrometry ,Rhizoctonia solani ,chemistry.chemical_compound ,Alkaloids ,Papaveraceae ,Drug Discovery ,Botany ,Sanguinarine ,Isoquinoline ,Pharmacology ,Macleaya cordata ,biology ,Traditional medicine ,Bacteria ,Fungi ,General Medicine ,biology.organism_classification ,Isoquinolines ,Anti-Bacterial Agents ,Chelerythrine ,Complementary and alternative medicine ,chemistry ,Protopine ,Indicators and Reagents ,Chromatography, Thin Layer ,Antibacterial activity - Abstract
Bioassay-guided fractionation of the crude extract of the whole plant of Macleaya cordata R. Br. led to the isolation of four alkaloids, which were identified as sanguinarine (1), chelerythrine (2), protopine (3) and α-allocryptopine (4) on the basis of their physicochemical and spectrometric data. Compounds 1 and 2 demonstrated a significant antifungal activity against the six test fungi with median inhibitory concentrations (IC50) ranging from 0.47 to 6.13 μg/mL. Compound 1 was the most effective with an IC50 of 0.47 μg/mL on Rhizoctonia solani. Furthermore, compounds 1 and 2 also demonstrated strong antibacterial activity, with IC50 values ranging from 5.01 to 11.3 μg/mL, and minimum inhibitory concentrations (MIC) ranging from 8.0 to 32.0 μg/mL. This is the first report on the activity of the alkaloids from M. cordata against economically important phytopathogenic fungi and bacteria.
- Published
- 2009
179. A study of gaits in Parkinson's patients using autoregressive model
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Zhanhong Ma, Yang Han, and Ping Zhou
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business.industry ,Speech recognition ,Pattern recognition ,Neurophysiology ,medicine.disease ,Gait ,Degenerative disease ,Autoregressive model ,Gait analysis ,Pattern recognition (psychology) ,medicine ,Artificial intelligence ,Psychology ,business ,Realization (probability) ,Motor skill - Abstract
Background: Parkinson's disease (PD) is a degenerative disease of the brain that often do harm to the motor skills of patients. A disturbed gait is very common among PD patients, who are easy to fall down and may lose their functional independence. Purpose: In this paper, we extract features from the gait signals in PD patients and control subjects for the purpose of comparison and realization of automatic recognition in computer. Also, we want to extract the pattern of walking in PD and help explain the disturbed gait through the perspective of bioinformatics. Method: In this paper, autoregressive (AR) model is applied to analysis of foot-pressure based on Yule-Walker equation for the calculation of power spectra. In the comparison process, we also give our own definition to Associated Discrete Index (ADI) in order to measure the discrete degree at a same frequency. Results: We analyze the data from three research groups: Ga, Ju and Si. The database includes 18, 25, 29 control subjects and 29, 29, 35 PD patients respectively. In the framework of 31–50Hz in the power spectra of Ga; 7–12Hz, 25–38Hz, 43–50Hz in Ju; and 2–10Hz in Si, we can see obvious difference between PD patient and control subject through t-test. Conclusions: The AR model can be used as a novel and useful tool to study the time series of foot-pressure. Associated Discrete Index could be an indicator in classification the gait signal in PD patient.
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- 2009
180. Analysis of Parkinson gait based on wavelet packet entropy
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Zhanhong Ma, Yang Han, Zhicheng Liu, and Ping Zhou
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Wavelet ,business.industry ,Network packet ,Computer science ,Feature extraction ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Entropy (information theory) ,Pattern recognition ,Artificial intelligence ,business ,Wavelet entropy ,Wavelet packet decomposition - Abstract
In this paper we show the possibility of using wavelet packet to analysis and characterize the gait signal of patients with Parkinson disease. Entropy has been defined to help extract the feature from results of wavelet packet decomposition. And the assessment of results has been performed by the means of T-test, showing that control group and PD group are statistically different from each other and our procedure based on wavelet packet could be applied to feature extraction of gait data.
- Published
- 2009
181. Atmospheric continuous filament discharge plasma (ACFDP) applied to crop sterilizatinon
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Haiguang Wang, Zhijie Zhu, Guixin Zhang, Zhanhong Ma, and Liang Liu
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Glow discharge ,Materials science ,Atmospheric pressure ,business.industry ,chemistry.chemical_element ,Dielectric barrier discharge ,Plasma ,law.invention ,chemistry ,law ,Electrode ,Optoelectronics ,Coaxial ,business ,Alternating current ,Helium - Abstract
Summary form only given. The ability of killing some microorganisms by atmospheric pressure glow discharges (APGD) has been demonstrated in a number of previous researches and can be extensively applied to medical treatment, sanitation, environmental protection and food reservation. At present, we designed a set of plasma device, which produce the dielectric barrier discharge plasma between the coaxial bar electrode and barrel electrode. This device adopts alternating current supply of 10 kHz to produce atmospheric continuous filament discharges plasma (ACFDP) at the gap distance of 5 mm and voltage of 15 kV. Because of the high exciting frequency, the plasma is generated constantly. We install nine of these devices in parallel and the applied power required to sustain stable discharges is around 400 W. When working gas (nitrogen, air, helium, etc) is inflated at a relatively high speed, the particle density decreases and the evenness degree of plasma increases, which is similar to the glow discharge. We use this plasma to treat some bacteria and fungus in crops, especially in wheat and the sterilization result is demonstrated to be remarkable
- Published
- 2006
182. An Investigation of the Influences of Mesoscale Ocean Eddies on Tropical Cyclone Intensities.
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ZHANHONG MA, JIANFANG FEI, LEI LIU, XIAOGANG HUANG, and YAN LI
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MESOSCALE eddies , *TROPICAL cyclones , *SIMULATION methods & models , *EDDIES , *OCEAN temperature , *METEOROLOGY statistical methods - Abstract
The impact of mesoscale ocean eddies on tropical cyclone intensities is investigated based on a combination of observations and atmosphere-ocean coupling simulations. A statistical analysis reveals that the tropical cyclone-eddy interactions occur at very high frequencies; over 90% of the recorded tropical cyclones over the western North Pacific have encountered ocean eddies from 2002 to 2011. The chances of confronting a cold core eddy (CCE) are slightly larger than confronting a warm core eddy (WCE). The observational sea surface temperature data have statistically evidenced that CCEs tend to promote the sea surface temperature decrease caused by tropical cyclones while WCEs tend to restrain such ocean responses. The roles of CCEs are statistically more significant than those of WCEs in modulating the sea surface temperature response. It is therefore proposed that CCEs should be paid no less attention than WCEs during the TC-ocean interaction process. The CCE-induced changes in sea surface temperature decreases are observed to be more remarkable for more intense and slower-moving tropical cyclones and for thinner depth of mixed layers. A set of numerical experiments reveal that the effects of ocean eddies are positively related to their strengths and storm intensities, and the eddy feedback is less pronounced when the eddy is located at one side of storm tracks than right below the tropical cyclone center. The eddy-induced moisture disequilibrium sooner vanishes after the departure of tropical cyclones. The intensity recoveries last for 1-2 days because of the dependence of surface enthalpy fluxes on surface winds. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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183. Multiparametric MRI in differentiating pulmonary artery sarcoma and pulmonary thromboembolism: a preliminary experience.
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Luo, Chunhai, Wang, Ying, Guo, Xiaojuan, Ma, Zhanhong, Yang, Yuanhua, Zhang, Tianjing, Min Liu, Xiaojuan Guo, Zhanhong Ma, Chunhai Luo, Ying Wang, Yuanhua Yang, Tianjing Zhang, and Liu, Min
- Subjects
MAGNETIC resonance imaging ,PULMONARY artery ,SARCOMA ,THROMBOEMBOLISM ,CANCER - Abstract
Purpose: We aimed to define multiparametric magnetic resonance imaging (MRI) findings to differentiate between pulmonary artery sarcoma (PAS) and pulmonary thromboembolism (PTE).Methods: Eleven patients with suspected PTE were prospectively included to undergo pulmonary MRI before surgery or biopsy. MRI protocol included an unenhanced sequence, diffusion-weighted imaging (DWI, b=800 s/mm2) and a dynamic contrast-enhanced sequence. Morphologic characteristics including distribution, filling defect, and intensity were observed on T1-, T2-, and fat-suppressed T2-weighted imaging, DWI, and contrast-enhanced MRI. Apparent diffusion coefficient (ADC) values were calculated.Results: Six patients were pathologically diagnosed as PAS and the other five as chronic PTE. There were no significant differences in age, gender, presenting symptoms, D-dimer, and N-terminal pro-brain natriuretic peptide between the two groups (P > 0.05). Among MRI findings that were tested for their ability to diagnose PAS, area under the curve (AUC) was significantly higher than 0.5 for main pulmonary artery involvement (AUC, 0.83±0.13; P = 0.011), hyperintensity on fat-suppressed T2-weighted imaging (AUC, 0.82±0.14; P = 0.025), hyperintensity on DWI (AUC, 0.88±0.12; P = 0.002), contrast enhancement (AUC, 0.92±0.10; P < 0.001) and pleural effusion (AUC, 0.82±0.14; P = 0.025). Moreover, grape-like appearance in distal pulmonary artery and cardiac invasion had 100% specificity for diagnosis of PAS. However, ADC value of PAS was not significantly different than that of chronic PTE (U, 12.00; P = 0.584).Conclusion: Hyperintense filling defect in main pulmonary artery on fat-suppressed T2-weighted imaging and DWI and contrast enhancement may help to discriminate PAS from PTE. [ABSTRACT FROM AUTHOR]- Published
- 2017
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184. Study of ultrafine particles-organic polymer thin films
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Z.Q. Xue, W.M. Liu, Jun Shen, Qihui Wu, Zhanhong Ma, Congshan Zhu, Hongyi Gao, Xingyu Zhao, S. J. Pang, and Y.W. Liu
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Fullerene ,Materials science ,genetic structures ,Metals and Alloys ,Nanotechnology ,Surfaces and Interfaces ,Crystal structure ,Polyethylene ,eye diseases ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,Lattice constant ,Carbon film ,Chemical engineering ,chemistry ,Transmission electron microscopy ,Ultrafine particle ,Materials Chemistry ,sense organs ,Thin film - Abstract
Au ultrafine particles-polyethylene thin films and C 60 -polyethylene thin films have been prepared in an ionized-cluster-beam time-of-flight mass spectrometer system and analysed by transmission electron microscopy. We found that the small Au clusters with a size of 2.0–5.0 nm are suspended randomly in the polyethylene thin films, and the C 60 -polyethylene thin films are f.c.c. structures with a lattice constant a of 1.454 nm.
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- 1993
185. Observed lattice structures of polyethylene with TEM and STM
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Zhanhong Ma, Hongyi Gao, Z.Q. Xue, Congshan Zhu, W.M. Liu, Xingyu Zhao, and S. J. Pang
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Plane parallel ,Materials science ,Crystal structure ,Polyethylene ,Condensed Matter Physics ,Surfaces, Coatings and Films ,law.invention ,Crystallography ,chemistry.chemical_compound ,chemistry ,Transmission electron microscopy ,law ,Ionization ,Lamellar structure ,Thin film ,Scanning tunneling microscope ,Instrumentation - Abstract
Polyethylene thin films were prepared by the ionized cluster beam (ICB) deposition technique. There are perfect polyethylene crystal lamellae in the thin films. We have analyzed polyethylene thin films with the transmission electron microscope (TEM) and found the (001) plane parallel to the surface of the substrate. There are strict periodic structures in the (110) plane, but no good periodic structures in the [110] direction. We have observed the polyethylene lamellar surface topography with the scanning tunneling microscope (STM), and found the fold chain structures on the (001) surface of polyethylene crystal lamellae.
- Published
- 1992
186. Antibacterial phenolics from chenopodiaceaeous plant Anabasis aphylla L
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Zhanhong Ma, Xiaojiang Hao, Jianglin Zhao, Ligang Zhou, Hongbing Yang, Ye Wang, and Hua Du
- Subjects
Chemistry ,Botany ,Bioengineering ,General Medicine ,Anabasis aphylla ,Applied Microbiology and Biotechnology ,Biotechnology - Published
- 2008
187. The effects of ocean feedback on tropical cyclone energetics under idealized air-sea interaction conditions
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Xiaogang Huang, Jianfang Fei, Zhanhong Ma, and Xiaoping Cheng
- Subjects
Atmospheric Science ,Work (thermodynamics) ,Atmospheric sciences ,Kinetic energy ,Boundary layer ,Geophysics ,Space and Planetary Science ,Latent heat ,Earth and Planetary Sciences (miscellaneous) ,Moist static energy ,Environmental science ,Tropical cyclone ,Equivalent potential temperature ,Lagrangian analysis - Abstract
[1] The effects of ocean feedback on the energetic characteristics of the tropical cyclone (TC) are investigated based on idealized TC-ocean coupling simulations. Results reveal notable impacts of ocean response on TC energetics. The ocean feedback reduces the latent energy of TCs, and consequently less latent heat is released in TC clouds, which leads to an evident decrease of the kinetic energy. A bulk equivalent potential temperature (θe) budget analysis demonstrates that the upward heat fluxes at the top of the boundary layer, of comparable magnitudes with the surface heat fluxes, are significantly diminished by the ocean feedback. A relatively higher portion of energy extracted from the ocean has been retained by the boundary layer under influences of the ocean feedback. The air parcels in contact with the cold wake possess evidently lowered moist static energy. To evaluate the evolution of moist static energy following these cooled air parcels, a three-dimensional Lagrangian analysis is conducted using a large sample of trajectory seeds. Statistical results indicate that there is a mixing process between the cooled and ambient air parcels that lasts mostly less than 240 min. Over 70% of the seeded air parcels approach to a radius of 30–90 km from the TC center before they obtain adequate energy from surrounding air to balance their negative asymmetric θe. Most of the cooled air parcels are warmed up in the boundary layer, thereby producing impacts on TC energetics through changing directly the moist static energy of the boundary layer. More work of real case simulations is required to generalize the findings reported herein.
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- 2013
188. Composition analysis of the volatile oil from endophytic fungus Pichia guilliermondii from Paris polyphylla var. Yunnanensis and its antibacterial activity
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Lijian Xu, Jianglin Zhao, Zhanhong Ma, Ligang Zhou, Xiaoyue Cai, and Yongfu Huang
- Subjects
Pichia guilliermondii ,Botany ,Bioengineering ,General Medicine ,Composition analysis ,Paris polyphylla var. yunnanensis ,Biology ,Endophytic fungus ,Antibacterial activity ,Applied Microbiology and Biotechnology ,Biotechnology - Published
- 2008
189. Antifungal activity of the extracts and fractions of six chenopodiaceaeous plant species
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Zhanhong Ma, Ligang Zhou, Hongbing Yang, Yaming Zhou, Hao Liu, Hua Du, and Chun Li
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Antifungal ,Traditional medicine ,medicine.drug_class ,medicine ,Plant species ,Bioengineering ,General Medicine ,Biology ,Applied Microbiology and Biotechnology ,Biotechnology - Published
- 2008
190. Forecast of maize dwarf mosaic using growth model forecasting method.
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Haiguang Wang and Zhanhong Ma
- Published
- 2010
191. A study of gaits in Parkinson's patients using autoregressive model.
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Yang Han, Zhanhong Ma, and Ping Zhou
- Published
- 2009
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192. Dual-source CT coronary angiographic evaluation of coronary artery fistulas.
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MIN LIU, QING HOU, XIAOJUAN GUO, SHUANGKUN WANG, and ZHANHONG MA
- Subjects
CORONARY angiography ,CORONARY artery surgery ,COMPUTED tomography ,LEFT heart ventricle ,FISTULA - Abstract
The aim of the present study was to retrospectively evaluate the incidence and morphological features of coronary artery fistulas (CAFs) detected by dual-source computed tomography coronary angiography (DS-CTCA). Between January 2011 and January 2013, 19,584 consecutive patients that had undergone electrocardiogram-triggering DS-CTCA were retrospectively reviewed. Image reconstructions were performed and image quality was evaluated. The medical information of the patients with CAF was reviewed from the medical records. Among the 19,584 patients, 66 patients were diagnosed with CAFs by CTCA, including 60 patients with coronary pulmonary artery fistulas (CPAFs) and six with coronary left ventricular fistulas. Therefore, the incidence of CAFs was 0.34%. Image quality was considered to be excellent in 61 patients and moderate in five cases. CPAFs were identified as small and tortuous vessels in 24 patients and dilated vessels close to the surface of the pulmonary artery (PA) in 36 patients. The coronary left ventricular fistulas were identified as dilated vessels that were draining into the posterior wall of the left ventricle. Among the 66 patients, 54 patients had one traceable fistula and the remaining 12 patients were shown to have two fistula vessels. The average diameter of the detected fistulas, measured with CTCA, was 3.1±1.9 mm. A high-density flow jet of contrast agent shunting from the fistula into the low density PA was observed in 46 patients with CPAF. The results indicate that DS-CTCA is a reliable noninvasive tool that allows the accurate delineation of CAFs. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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193. Non-invasive evaluation of hemodynamics in pulmonary hypertension by a Septal angle measured by computed tomography pulmonary angiography: Comparison with right-heart catheterization and association with N-terminal pro-B-type natriuretic peptide.
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QIANG TANG, MIN LIU, ZHANHONG MA, XIAOJUAN GUO, TUGUANG KUANG, and YUANHUA YANG
- Subjects
PULMONARY hypertension treatment ,CARDIAC catheterization ,NATRIURETIC peptides ,HEMODYNAMICS ,PULMONARY hypertension ,HYPERTENSION ,THERAPEUTICS ,COMPUTED tomography ,ENZYME-linked immunosorbent assay ,PATIENTS - Abstract
The septal angle, an angle between the interventricular septum and the line connecting the sternum midpoint and thoracic vertebral spinous process, as measured by computed tomographic pulmonary angiography (CTPA), has been observed to be increased in patients with pulmonary hypertension (PH), but its meaning remains unclear. The aim of this study was to investigate the potential role of the septal angle in evaluating hemodynamics and its association with N-terminal pro-B-type natriuretic peptide (NT-proBNP) in patients with PH. Patients with PH (n=106), including 76 with chronic thromboembolic pulmonary hypertension (CTEPH) and 30 with pulmonary artery hypertension (PAH), were retrospectively reviewed. The patients underwent CTPA prior to right-heart catheterization. The septal angle was measured on transversal CTPA images. Hemodynamic parameters were evaluated by right-heart catheterization. The level of plasma NT-proBNP was measured by enzyme-linked sandwich immunoassay. The septal angle had a moderate correlation with cardiac output (CO; r=-0.535, P=0.000) and a high correlation with pulmonary vascular resistance (PVR; r=0.642, P=0.000). The mean level of NT-proBNP in PH was 1,716.09±1,498.30 pg/ml, which correlated with the septal angle (r=0.693, P=0.000). In a stepwise forward regression analysis, the Septal angle was entered into the final equation for predicting PVR, leading to the following equation: PVR = 28.256 x Septal angle - 728.72. In CTEPH, the Septal angle strongly correlated with NT-proBNP (r=0.668, P=0.000) and PVR (r=0.676, P=0.000). In PAH, the Septal angle strongly correlated with NT-proBNP (r=0.616, P=0.003) and PVR (r=0.623, P=0.000). The CTPA-derived Septal angle is a superior predictor for evaluating and monitoring the level of NT-proBNP and PVR in patients with PH. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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194. Killing the teliospores of tilletia controversa Kuhn (TCK) with atmospheric microwave plasma.
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Jian Feng, Guixin Zhang, Liang Liu, Shumin Wang, Qing Zhang, Zhenyu Sun, Zhanhong Ma, and Haiguang Wang
- Published
- 2008
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195. Atmospheric continuous filament discharge plasma (ACFDP) applied to crop sterilizatinon.
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Liang Liu, Guixin Zhang, Zhijie Zhu, Haiguang Wang, and Zhanhong Ma
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- 2006
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196. Clonal Expansion and Dispersal Pathways of Puccinia polysora in China.
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Qiuyu Sun, Jie Liu, Chong Huang, Xiufeng Liu, Jianmeng Gao, Leifu Li, Yong Luo, and Zhanhong Ma
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- *
PUCCINIA , *MICROSATELLITE repeats , *POPULATION genetics , *GENETIC variation , *RUST diseases , *MOLECULAR cloning , *LEAF rust of wheat - Abstract
Southern corn rust (SCR) caused by Puccinia polysora is one of the most devastating diseases in the world. In recent years, SCR has been upgraded from a minor to a major disease around the world, including in China. However, little is known about its population genetics and structure in China. In this study, we analyzed 288 isolates collected from various localities during 2017 in seven Chinese provinces: Guangxi, Guangdong, Anhui, Hunan, Shandong, Henan, and Shaanxi. The isolates were analyzed using nine microsatellite markers. The population structure, genetic diversity, and reproduction mode of P. polysora were investigated based on genotype data. Strong genotypic diversity was detected and clonal reproduction was dominant. The populations collected from the pathogen's winter-reproductive regions harbored more genotypes than those collected from the pathogen's epidemic regions. The spatial differences in genotypic richness, and evenness among the populations were significant, and showed a decreasing trend from south to north. Most isolates were clustered into two clonal groups. Two high-frequency multilocus genotypes (MLGs), MLG1 and MLG2, were widely distributed in all populations. Our analyses confirmed that P. polysora employed clone dispersal from the pathogen's winter-reproductive regions to the pathogen's epidemic regions, and in addition to the sources from the pathogen's winter-reproductive regions, the pathogen in Anhui and Hunan might also have other sources from areas such as Taiwan, China, or/and Southeast Asia, and the pathogen went through a genetic bottleneck during its dispersal. These findings provide initial insights into the reproduction mode and dispersal pathways of P. polysora in China. [ABSTRACT FROM AUTHOR]
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- 2023
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197. Long-Distance Spore Transport of Wheat Stripe Rust Pathogen from Sichuan, Yunnan, and Guizhou in Southwestern China.
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Haiguang Wang, Yang, X. B., and Zhanhong Ma
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- *
PUCCINIA striiformis , *WHEAT diseases & pests , *PATHOGENIC microorganisms , *DISEASED plants - Abstract
Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is the most devastating wheat disease in China. Although pathogens oversummering and overwintering in many regions of southwestern China have been studied, spore exchange among these regions is largely unknown. It is especially important to study the role of Sichuan, Yunnan, and Guizhou provinces in southwestern China in contributing to regional disease outbreaks in the major wheat-growing areas of China. Long-distance transport of P. striiformis f. sp. tritici urediniospores after oversummering and overwintering in Sichuan, Yunnan, and Guizhou was investigated using the HYSPLIT-4 model based on meteorological data. Results suggest that the pathogen spores can interchange frequently among Sichuan, Yunnan, and Guizhou in both spring and autumn. The sources of inoculum in Sichuan, Yunnan, and Guizhou have a high probability of impacting the epidemics in northern, northwestern, and southwestern China. In particular, disease epidemics in Guizhou can be affected not only by local inoculum but also by that from Yunnan in the spring. [ABSTRACT FROM AUTHOR]
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- 2010
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198. Genetic Structure and Asymmetric Migration of Wheat Stripe Rust Pathogen in Western Epidemic Areas of China.
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Junmin Liang, Xiufeng Liu, Tsui, Clement K. M., Zhanhong Ma, and Yong Luo
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- *
STRIPE rust , *WHEAT rusts , *AMPLIFIED fragment length polymorphism , *MICROSATELLITE repeats , *PRINCIPAL components analysis , *PUCCINIA striiformis - Abstract
Puccinia striiformis f. sp. tritici causes severe global epidemics of wheat stripe rust primarily by airborne urediniospores. Understanding long-distance migration patterns of P. striiformis f. sp. tritici is critical for disease forecasting and management. Although the western epidemic areas in China have been considered as the source of inoculum spread eastward across the country, migration pathways among different populations within the western epidemic areas are poorly understood. In this study, we investigated the population genetics of 200 P. striiformis f. sp. tritici isolates from western epidemic areas using amplified fragment length polymorphism and simple sequence repeat markers. A coalescent approach was also used to calculate the migration rates among populations. Data analyses with both marker systems indicated high genetic diversity in each regional population. The Mantel test revealed significant positive correlation between genetic and geographic distances. Both discriminant analysis of principal components and STRUCTURE analysis supported moderate population structure shaped by seasonality and geography. The calculated migration rates indicated the presence of asymmetric migration between major populations in western epidemic areas, with greater migration rates from high elevation, oversummering areas to low elevation, overwintering areas. Sichuan Basin, one of the low elevation, overwintering areas, sampled in both fall and spring, was inferred as a recipient in fall but a donor in spring. Migration among P. striiformis f. sp. tritici populations may be partly attributable to terrace farming and prevailing wind direction in different seasons. Our study provides a better understanding of fine-scale population structure and the interregional migration pattern of P. striiformis f. sp. tritici in northwestern China and will inform future rust management. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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199. Effects of Climate Change on Epidemics of Powdery Mildew in Winter Wheat in China.
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Xiuli Tang, Xueren Cao, Xiangming Xu, Yuying Jiang, Yong Luo, Zhanhong Ma, Jieru Fan, and Yilin Zhou
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- *
WINTER wheat , *CLIMATE change , *EPIDEMICS , *ATMOSPHERIC temperature , *GLOBAL temperature changes , *HUMIDITY - Abstract
Powdery mildew is a highly destructive winter wheat pathogen in China. Since the causative agent is sensitive to changing weather conditions, we analyzed climatic records from regions with previous wheat powdery mildew epidemics (1970 to 2012) and investigated the long-term effects of climate change on the percent acreage (PA) of the disease. Then, using PA and the pathogen’s temperature requirements, we constructed a multi-regression model to predict changes in epidemics during the 2020s, 2050s, and 2080s under representative concentration pathways RCP2.6, RCP4.5, and RCP8.5. Mean monthly air temperature increased from 1970 to 2012, whereas hours of sunshine and relative humidity decreased (P < 0.001). Year-to-year temperature changes were negatively associated with those of PA during oversummering and late spring periods of disease epidemics, whereas positive relationships were noted for other periods, and year-to-year changes in relative humidity were correlated with PA changes in the early spring period of disease epidemics (P < 0.001). Our models also predicted that PA would increase less under RCP2.6 (14.43%) than under RCP4.5 (14.51%) by the 2020s but would be higher by the 2050s and 2080s and would increase least under RCP8.5 (14.37% by the 2020s). Powdery mildew will, thus, pose an even greater threat to China’s winter wheat production in the future. [ABSTRACT FROM AUTHOR]
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- 2017
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200. Modeling of the overwintering distribution of Puccinia striiformis f. sp. tritici based on meteorological data from 2001 to 2012 in China
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Xiaojing WANG,Zhanhong MA,Yuying JIANG,Shouding SHI,Wancai LIU,Juan ZENG,Zhiwei ZHAO,Haiguang WANG
- Subjects
stripe rust ,wheat ,overwintering ,geospatial distribution ,geographic information system ,climate change ,Agriculture (General) ,S1-972 - Abstract
Wheat stripe rust caused by Puccinia striiformis f. sp. tritici occurs widely in China and seriously affects wheat production. Global warming could profoundly impact the incidence and prevalence of low-temperature diseases such as stripe rust. Studies on the effects of temperature on the distribution of overwintering stripe rust could help us understand the incidence and prevalence of the disease and could also provide support for monitoring, forecasting and developing control strategies. An exponential model and a spherical model of the ordinary Kriging method in the ArcGIS platform were used to predict the overwintering regions of stripe rust based on the probability that the average temperature of the coldest month from December to February was higher than -6 or -7ºC from 2001 to 2012. The results showed that the areas with a probability between 70% and 90% were transition regions for the overwintering of stripe rust. Based on annual mean temperature of the coldest month from December to February for 2001 to 2012, overwintering distribution of stripe rust was likewise evaluated. The boundary for overwintering of stripe rust was consistent with the areas where the probability was predicted to be 70% to 90% for the overwintering distribution of stripe rust, but the boundary was shifted northward toward Beijing in North China. Some areas in Xinjiang, including Akto, Pishan, Hotan and Yutian, were also predicted to be suitable for the overwintering of stripe rust.
- Published
- 2014
- Full Text
- View/download PDF
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