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Search Results: 1 - 10 of 270146 matches for " Mahboob Iqbal;Jie Chen;Wei Yang;Pengbo Wang;Bing Sun "
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SAR Image Despeckling by Selective 3D Filtering of Multiple Compressive Reconstructed Images
Mahboob Iqbal;Jie Chen;Wei Yang;Pengbo Wang;Bing Sun
PIER , 2013, DOI: 10.2528/PIER12091504
Abstract: A despeckling technique based on multiple image reconstruction and selective 3-dimensional filtering is proposed. Multiple SAR images are reconstructed from a single SAR image by employing compressive sensing (CS) theory. In order to obtain multiple images from single SAR image, multiple subsets of pixels are selected from input SAR image by imposing restriction that each subset has at least 20% different pixels than any other subset. These subsets are taken as measurement vectors in CS framework to obtain multiple SAR images. A despeckled image is obtained by employing selective 3-dimensional filtering to multiple reconstructed SAR image. The proposed technique is tested on single look complex TerraSAT-X data set, and experimental results exhibit that the proposed technique outperformed benchmark despekling methods in terms of visual quality and despeckling quality metrics.
Kalman Filter for Removal of Scalloping and Inter-Scan Banding in Scansar Images
Mahboob Iqbal;Jie Chen;Wei Yang;Pengbo Wang;Bing Sun
PIER , 2012, DOI: 10.2528/PIER12082107
Abstract: Spaceborne synthetic aperture radar (SAR) plays more and more important role in Earth observation science, especially with ScanSAR mode which provides wide-swath coverage with moderate resolution. However, scalloping and inter-scan banding (ISB) are two major artifacts, which signi cantly degrade the quality of ScanSAR images. In this paper, a novel technique for removal of scalloping and ISB in ScanSAR images is proposed. Scalloping and ISB artifacts are modeled by two-dimensional gain and o set parameters varying as function of both azimuth time and range position. The gain and o set parameters can be split into azimuth and range components. The variations of gain/o set with respect to azimuth and range positions would represent scalloping and ISB artifacts respectively. In the proposed technique, recursive and minimum mean square error (MMSE) estimates of azimuth gain/o set parameters are found out by using Kalman lter for each azimuth location in a subswath by considering corresponding range samples as observation vector. Subsequently, range gain/o set parameters causing ISB artifacts are estimated by using Kalman lter for each range positions by considering azimuth samples as observation vector. The MMSE estimates of gain/o set parameters are used to directly remove scalloping and ISB artifacts. The proposed scheme was applied on simulated as well as calibrated real ScanSAR images. The experimental results exhibited the potential of proposed technique to be used as post processing tool for enhancing ScanSAR image quality.
A Novel Image Formation Algorithm for High-Resolution Wide-Swath Spaceborne SAR Using Compressed Sensing on Azimuth Displacement Phase Center Antenna
Jie Chen;Jianhu Gao;Yanqing Zhu;Wei Yang;Pengbo Wang
PIER , 2012, DOI: 10.2528/PIER11121101
Abstract: High-resolution wide-swath (HRWS) imaging with spaceborne synthetic aperture radar (SAR) can be achieved by using azimuth displacement phase center antenna (DPCA) technique. However, it will consequently leads to extremely high data rate on satellite downlink system. A novel sparse sampling scheme based on compressed sensing (CS) theory for azimuth DPCA SAR was proposed, by which only a small proportion of radar echoes are utilized for imaging to reduce data rate. The corresponding image formation algorithm for the proposed scheme was presented in the paper. The SAR echo signal of each channel can be reconstructed with high probability by using orthogonal matching pursuit (OMP) algorithm in Doppler frequency domain. The reconstructed echo signals of each channel are jointly processed by means of spectrum reconstructing filter for compensating Doppler spectrum aliasing resulting from non-uniform sampling in azimuth direction. The high quality SAR image can be obtained by using chirp scaling algorithm. The effectiveness of the proposed approach was validated by computer simulations using both point targets and distributed targets.
A Novel Three-Step Image Formation Scheme for Unified Focusing on Spaceborne SAR Data
Wei Yang;Jie Chen;Hongceng Zeng;Jian Zhou;Pengbo Wang;Chun-Sheng Li
PIER , 2013, DOI: 10.2528/PIER12122309
Abstract: Current advanced spaceborne synthetic aperture radar (SAR) systems may operate at multiple imaging modes, including conventional modes as stripmap, ScanSAR and spotlight, as well as the state-of-the-art SAR modes, e.g., sliding spotlight, TOPS (Terrain Observation by Progressive Scans) and inverse TOPS, etc. A novel image formation scheme for unified processing spaceborne SAR data was proposed, which significantly simplified complexity of SAR processor sub-system. The unified-model-coefficient (UMC) was defined for modeling all SAR modes by means of analyzing both imaging geometry and time-frequency diagram corresponding to each imaging mode, respectively. The unified mathematical formula for modeling all SAR modes echo signal was derived as a function of UMC. Consequently, a unified image formation scheme for accurately focusing spaceborne SAR data in an arbitrary mode was proposed, which integrates all of SAR image formation procedures into a standard three-step processing framework, namely, de-rotation, data focusing and re-sampling, which evidently improve efficiency and robustness of data processing sub-system. Computer simulation experiment results verify the effectiveness of the proposed scheme.
Relationship of carotid intima-media thickness and duration of vegetarian diet in Chinese male vegetarians
Shu-Yu Yang, Hui-Jie Zhang, Su-Yun Sun, Li-Ying Wang, Bing Yan, Chang-Qin Liu, Wei Zhang, Xue-Jun Li
Nutrition & Metabolism , 2011, DOI: 10.1186/1743-7075-8-63
Abstract: One hundred and seventy-one Chinese male vegetarians were screened for metabolic profile, cardiovascular risk and carotid IMT. They were compared with 129 age-matched omnivores recruited from a community-based health project. The effects of confounding factors were adjusted by stepwise logistic regression analysis.Compared to the omnivores, the vegetarians had lower BMI, weight, systolic blood pressure and diastolic blood pressure. Also, the levels of triglyceride, total cholesterol, HDL-Cholesterol, LDL-Cholesterol, ApoA1, ApoB, uric acid, albumin and γ-glutamyltransferase were significantly reduced in vegetarians. Omnivores had significantly higher fasting blood glucose than that of vegetarians. However, there were no differences in fasting insulin, C-reactive protein and HOMA-IR between the two groups. IMT was thinner in the vegetarian group than in the omnivore group (0.59 ± 0.16 vs. 0.63 ± 0.10 cm, P < 0.05). The vegetarians were divided according to duration of vegetarian diet (< 6 years, 6 to ≤ 11 years, > 11 years), those in tertile 1 (< 6 years) and tertile 2 (6 to ≤ 11 years) had shown thinner IMT as compared to the omnivores, and tertile 3 had shown no reduction.A decrease in multiple cardiovascular risk factors such as BMI, blood pressure and lipid profile was associated with vegetarian diet. Moreover, taking a low-calorie, low-protein, or vegetarian diet might have great beneficial effects on IMT through improved lipid profile, and the beneficial effects appeared to be correlated with the duration of vegetarian diet.The effects of vegetarian diets on the prevention of cardiovascular diseases (CVD) had been reported extensively. As a specific population which has successfully made long-term lifestyle modifications, the vegetarian diet could provide important insights into the potential efficacy of a diet in reducing cardiometabolic risk. Many studies have shown that vegetarians had both lower blood pressure and cardiovascular mortality as compared with o
Novel Evolved Immunoglobulin (Ig)-Binding Molecules Enhance the Detection of IgM against Hepatitis C Virus
Jie Cao,Qiuli Chen,Huaqun Zhang,Peipei Qi,Chao Liu,Xufang Yang,Niansong Wang,Baohua Qian,Jinhong Wang,Shaohua Jiang,Hua Yang,Shuhan Sun,Wei Pan
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0018477
Abstract: Detection of specific antibodies against hepatitis C virus (HCV) is the most widely available test for viral diagnosis and monitoring of HCV infections. However, narrowing the serologic window of anti-HCV detection by enhancing anti-HCV IgM detection has remained to be a problem. Herein, we used LD5, a novel evolved immunoglobulin-binding molecule (NEIBM) with a high affinity for IgM, to develop a new anti-HCV enzyme-linked immunosorbent assay (ELISA) using horseradish peroxidase-labeled LD5 (HRP-LD5) as the conjugated enzyme complex. The HRP-LD5 assay showed detection efficacy that is comparable with two kinds of domestic diagnostic kits and the Abbott 3.0 kit when tested against the national reference panel. Moreover, the HRP-LD5 assay showed a higher detection rate (55.9%, 95% confidence intervals (95% CI) 0.489, 0.629) than that of a domestic diagnostic ELISA kit (Chang Zheng) (53.3%, 95% CI 0.463, 0.603) in 195 hemodialysis patient serum samples. Five serum samples that were positive using the HRP-LD5 assay and negative with the conventional anti-HCV diagnostic ELISA kits were all positive for HCV RNA, and 4 of them had detectable antibodies when tested with the established anti-HCV IgM assay. An IgM confirmation study revealed the IgM reaction nature of these five serum samples. These results demonstrate that HRP-LD5 improved anti-HCV detection by enhancing the detection of anti-HCV IgM, which may have potential value for the early diagnosis and screening of hepatitis C and other infectious diseases.
Role of cathepsin B-mediated apoptosis in fulminant hepatic failure in mice
Bing-Zhu Yan, Wei Wang, Li-Yan Chen, Man-Ru Bi, Yan-Jie Lu, Bao-Xin Li, Bao-Shan Yang
World Journal of Gastroenterology , 2009,
Abstract: AIM: To investigate the pathogenic role of cathepsin B and the protective effect of a cathepsin B inhibitor (CA-074Me) in fulminant hepatic failure in mice.METHODS: LPS/D-Gal N was injected into mice of the model group to induce fulminant hepatic failure; the protected group was administered CA-074me for 30 min before LPS/D-Gal N treatment; the normal group was given isochoric physiologic saline. Liver tissue histopathology was determined with HE at 2, 4, 6 and 8 h after Lps/D-Gal injection. Hepatocyte apoptosis was examined by TUNEL method. The expression of cathepsin B in liver tissues was investigated by immunohistochemistry, Western blot and RT-PCR.RESULTS: Compared with the normal group, massive typical hepatocyte apoptosis occurred in the model group; the number of apoptotic cells reached a maximum 6 h after injection. The apoptosis index (AI) in the protected group was clearly reduced (30.4 ± 2.8 vs 18.1 ± 2.0, P < 0.01 ). Cathepsin B activity was markedly increased in drug-treated mice compared with the normal group (P < 0.01). Incubation with LPS/D-Gal N at selected time points resulted in a time-dependent increase in cathepsin B activity, and reached a maximum by 8 h. The expression of cathepsin B was significantly decreased in the protected group (P < 0.01).CONCLUSION: Cathepsin B plays an essential role in the pathogenesis of fulminant hepatic failure, and the cathepsin B inhibitor CA-074me can attenuate apoptosis and liver injury.
Advances and perspectives in catalytic oxidation of hydrocarbons in liquid phase

Zhou Lipeng,Yang Guanyu,Zhang Wei,Sun Zhiqiang,Gao Jin,Miao Hong,Chen Chen,Ma Hong,Li Xiaoqiang,Zhang Qiaohong,Wang Feng,Tong Xinli,Xu Jie,

自然科学进展 , 2007,
Abstract:
Increase of ADAM10 Level in Coronary Artery In-Stent Restenosis Segments in Diabetic Minipigs: High ADAM10 Expression Promoting Growth and Migration in Human Vascular Smooth Muscle Cells via Notch 1 and 3
Ke Yang, Lin Lu, Yan Liu, Qi Zhang, Li Jin Pu, Lin Jie Wang, Zhen Bing Zhu, Ya. Nan Wang, Hua Meng, Xiao Jie Zhang, Run Du, Qiu Jing Chen, Wei Feng Shen
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0083853
Abstract: Background This study aimed to identify major proteins in the pathogenesis of coronary artery in-stent restenosis (ISR) in diabetic minipigs with sirolimus-eluting stenting, and to investigate the roles of key candidate molecules, particularly ADAM10, in human arterial smooth muscle cells (HASMCs). Methods and Results The stents were implanted in the coronary arteries of 15 diabetic and 26 non-diabetic minipigs, and angiography was repeated at six months. The intima of one vascular segment with significant ISR and one with non-ISR in diabetic minipigs were isolated and cultured in conditioned medium (CM). The CM was analyzed by LC-MS/MS to uncover proteins whose levels were significantly increased (≥1.5-fold) in ISR than in non-ISR tissues. After literature searching, we focused on the identified proteins, whose biological functions were most potentially related to ISR pathophysiology. Among them, ADAM10 was significantly increased in diabetic and non-diabetic ISR tissues as compared with non-ISR controls. In cell experiments, retrovirus-mediated overexpression of ADAM10 promoted growth and migration of HASMCs. The effects of ADAM10 were more remarkable in high-glucose culture than in low-glucose culture. Using shRNA and an inhibitor of γ-secretase (GSI), we found that the influences of ADAM10 were in part mediated by Notch1 and notch 3 pathway, which up-regulated Notch downstream genes and enhanced nuclear translocation of the small intracellular component of Notch1 and Notch3. Conclusions This study has identified significantly increased expression of ADAM10 in the ISR versus non-ISR segment in diabetic minipigs and implicates ADAM10 in the enhanced neointimal formation observed in diabetes after vascular injury.
Area Disease Estimation Based on Sentinel Hospital Records
Jin-Feng Wang, Ben Y. Reis, Mao-Gui Hu, George Christakos, Wei-Zhong Yang, Qiao Sun, Zhong-Jie Li, Xiao-Zhou Li, Sheng-Jie Lai, Hong-Yan Chen, Dao-Chen Wang
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023428
Abstract: Background Population health attributes (such as disease incidence and prevalence) are often estimated using sentinel hospital records, which are subject to multiple sources of uncertainty. When applied to these health attributes, commonly used biased estimation techniques can lead to false conclusions and ineffective disease intervention and control. Although some estimators can account for measurement error (in the form of white noise, usually after de-trending), most mainstream health statistics techniques cannot generate unbiased and minimum error variance estimates when the available data are biased. Methods and Findings A new technique, called the Biased Sample Hospital-based Area Disease Estimation (B-SHADE), is introduced that generates space-time population disease estimates using biased hospital records. The effectiveness of the technique is empirically evaluated in terms of hospital records of disease incidence (for hand-foot-mouth disease and fever syndrome cases) in Shanghai (China) during a two-year period. The B-SHADE technique uses a weighted summation of sentinel hospital records to derive unbiased and minimum error variance estimates of area incidence. The calculation of these weights is the outcome of a process that combines: the available space-time information; a rigorous assessment of both, the horizontal relationships between hospital records and the vertical links between each hospital's records and the overall disease situation in the region. In this way, the representativeness of the sentinel hospital records was improved, the possible biases of these records were corrected, and the generated area incidence estimates were best linear unbiased estimates (BLUE). Using the same hospital records, the performance of the B-SHADE technique was compared against two mainstream estimators. Conclusions The B-SHADE technique involves a hospital network-based model that blends the optimal estimation features of the Block Kriging method and the sample bias correction efficiency of the ratio estimator method. In this way, B-SHADE can overcome the limitations of both methods: Block Kriging's inadequacy concerning the correction of sample bias and spatial clustering; and the ratio estimator's limitation as regards error minimization. The generality of the B-SHADE technique is further demonstrated by the fact that it reduces to Block Kriging in the case of unbiased samples; to ratio estimator if there is no correlation between hospitals; and to simple statistic if the hospital records are neither biased nor space-time correlated. In addition to
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