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Now showing items 113 - 128 of 134

  • Cerebral vasculopathy in a Chinese family with neurofibromatosis type I mutation

    Liang, Jian-Tao   Huo, Li-Rong   Bao, Yu-Hai   Wang, Zhen-Yu   Ling, Feng  

    Neurofibromatosis type I (NF1) is a hereditary, autosomal dominant, neurocutaneous syndrome that is attributed to NF1 gene mutation. NF1 has been associated with scoliosis, macrocephaly, pseudoarthrosis, short stature, mental retardation, and malignancies. NF1-associated vasculopathy is an uncommon and easily-overlooked presentation. Examination of a Chinese family affected by NF1 combined with cerebral vessel stenosis and/or abnormality suggested a possible relationship between NF1 and vessel stenosis. To determine which NF1 gene mutation is associated with vascular lesions, particularly cerebral vessel stenosis, we examined one rare family with combined cerebral vessel lesions or maldevelopment. Vascular lesions were detected using transcranial Doppler sonography and digital subtraction angiography in family members. Next, denaturing high-performance liquid chromatography and sequencing were used to screen for NF1 gene mutations. The results revealed a nonsense mutation, c.541C > T, in the NF1 gene. This mutation truncated the NF1 protein by 2659 aminoacid residues at the C-terminus and co-segregated with all of the patients, but was not present in unaffected individuals in the family. Exceptionally, three novel mutations were identified in unaffected family members, but these did not affect the product of the NF1 gene. Thus the nonsense mutation, c.541C > T, located in the NF1 gene could constitute one genetic factor for cerebral vessel lesions.
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  • Poly[2,7-(9,9-dihexylfluorene)]-block-poly[2-(dimethylamino)ethylmethacrylate] as resilient cathode interlayers in polymer solar cells: the effect of block ratios

    Fu, Jianfei   Yuan, Ligang   Ling, Feng   Duan, Ruomeng   Chen, Qiaoyun   Ma, Hui   Zhou, Mi   Song, Bo   Zhou, Yi   Li, Yongfang  

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  • Optimal Endmember-Based Super-Resolution Land Cover Mapping

    Li, Xinyan   Li, Xiaodong   Foody, Giles   Yang, Xiaohong   Zhang, Yihang   Du, Yun   Ling, Feng  

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  • An Iterative Interpolation Deconvolution Algorithm for Superresolution Land Cover Mapping

    Ling, Feng   Foody, Giles M.   Ge, Yong   Li, Xiaodong   Du, Yun  

    Superresolution mapping (SRM) is a method to produce a fine-spatial-resolution land cover map from coarse-spatial-resolution remotely sensed imagery. A popular approach for SRM is a two-step algorithm, which first increases the spatial resolution of coarse fraction images by interpolation and then determines class labels of fine-resolution pixels using the maximum a posteriori (MAP) principle. By constructing a new image formation process that establishes the relationship between the observed coarse-resolution fraction images and the latent fine-resolution land cover map, it is found that the MAP principle only matches with area-to-point interpolation algorithms and should be replaced by deconvolution if an area-to-area interpolation algorithm is to be applied. A novel iterative interpolation deconvolution (IID) SRM algorithm is proposed. The IID algorithm first interpolates coarse-resolution fraction images with an area-to-area interpolation algorithm and produces an initial fine-resolution land cover map by deconvolution. The fine-spatial-resolution land cover map is then updated by reconvolution, back-projection, and deconvolution iteratively until the final result is produced. The IID algorithm was evaluated with simulated shapes, simulated multispectral images, and degraded Landsat images, including comparison against three widely used SRM algorithms: pixel swapping, bilinear interpolation, and Hopfield neural network. Results show that the IID algorithm can reduce the impact of fraction errors and can preserve the patch continuity and the patch boundary smoothness simultaneously. Moreover, the IID algorithm produced fine-resolution land cover maps with higher accuracies than those produced by other SRM algorithms.
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  • Study on Regional Division Based on Self-Adaptive FCM Clustering

    Shi, Shuicai   Ling, Feng   Lv, Xueqiang   Li, Shengdong  

    Through researching and analyzing self-adaptive strategy and fuzzy C-means (;FCM); clustering algorithm, we put them together to form a self-adaptive FCM clustering algorithm. It is a good solution to the problem of local optimum as well as sensitivity to the initial value for the traditional FCM clustering algorithm. Finally, the new algorithm has been used in the regional division of police patrols in a city. In the division of the region, it has been proved by experiments that the sum of distance between a police vehicle and each possible accident scene can achieve the minimum value, which shows a significant effect of police patrols. And through the improved dijkstra algorithm to calculate shortest path length between a police vehicle and an accident scene, it proves that a police vehicle in the division of the region arrives at an accident scene within three minutes after accepting the warnings, whose proportion is 90.2%;.
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  • Mitochondrial fission proteins Fis1 and Mdv1, but not Dnm1, play a role in maintenance of heteroplasmy in budding yeast

    Bradshaw, Elliot   Yoshida, Minoru   Ling, Feng  

    In budding yeast, the mitochondrial DNA (mtDNA) replication pathway involving the homologous DNA pairing protein Mhr1 promotes mitochondrial allele segregation. Mitochondrial fusion facilitates the recombination-mediated replication pathway; however, the role of fission remains largely unknown. By monitoring mitochondrial allele segregation during zygotic division, we found that the absence of fission proteins Fis1 or Mdv1, but not Dnm1, resulted in increased initial homoplasmy levels and decreased mtDNA copy number. However, decreases in mtDNA copy number alone were not sufficient for rapid establishment of homoplasmy, suggesting that inhibiting the activities of certain fission proteins promotes homoplasmy by reducing the number of mtDNA segregation units. (C) 2012 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.
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  • Cilia oscillations

    Man, Yi   Ling, Feng   Kanso, Eva  

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  • Super-resolution land-cover mapping using multiple sub-pixel shifted remotely sensed images

    Ling, Feng   Du, Yun   Xiao, Fei   Xue, Huaiping   Wu, Shengjun  

    Super-resolution land-cover mapping is a promising technology for prediction of the spatial distribution of each land-cover class at the sub-pixel scale. This distribution is often determined based on the principle of spatial dependence and from land-cover fraction images derived with soft classification technology. However, the resulting super-resolution land-cover maps often have uncertainty as no information about sub-pixel land-cover patterns within the low-resolution pixels is used in the model. Accuracy can be improved by incorporating supplemental datasets to provide more land-cover information at the sub-pixel scale; but the effectiveness of this is limited by the availability and quality of these additional datasets. In this paper, a novel super-resolution land-cover mapping technology is proposed, which uses multiple sub-pixel shifted remotely sensed images taken by observation satellites. These satellites take images over the same area once every several days, but the images are not identical because of slight orbit translations. Low-resolution pixels in these remotely sensed images therefore contain different land-cover fractions that can provide useful information for super-resolution land-cover mapping. We have constructed a Hopfield Neural Network (HNN) model to solve it. Maximum spatial dependence is the goal of the proposed model, and the fraction maps of all images are constraints added to the energy function of HNN. The model was applied to synthetic artificial images as well as to a real degraded QuickBird image. The output maps derived from different numbers of images at different zoom factors were compared visually and quantitatively to the super-resolution map generated from a single image. The resulting land-cover maps with multiple remotely sensed images were more accurate than was the single image map. The use of multiple remotely sensed images is therefore a promising method for decreasing the uncertainty of super-resolution land-cover mapping. Moreover, remotely sensed images with similar spatial resolution from different satellite platforms can be used together, allowing a fusion of information obtained from remotely sensed imagery.
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  • Specific and nonspecific thalamocortical functional connectivity in normal and vegetative states

    Zhou, Jingsheng   Liu, Xiaolin   Song, Weiqun   Yang, Yanhui   Zhao, Zhilian   Ling, Feng   Hudetz, Anthony G.   Li, Shi-Jiang  

    Recent theoretical advances describing consciousness from information and integration have highlighted the unique role of the thalamocortical system in leading to integrated information and thus, consciousness. Here, we examined the differential distributions of specific and nonspecific thalamocortical functional connections using resting-state fMRI in a group of healthy subjects and vegetative-state patients. We found that both thalamic systems were widely distributed, but they exhibited different patterns. Nonspecific connections were preferentially associated with brain regions involved in higher-order cognitive processing, self-awareness and introspective mentalizing (e.g., the dorsal prefrontal and anterior cingulate cortices). In contrast, specific connections were prevalent in the ventral and posterior part of the prefrontal and precuneus, known involved in representing externally-directed attentions. Significant reductions of functional connectivity in both systems, especially the nonspecific system, were observed in VS. These data suggest that brain networks sustaining information and integration may be differentiated by the nature of their thalamic functional connectivity. (C) 2010 Elsevier Inc. All rights reserved.
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  • Traumatic spinal perimedullary arteriovenous fistula: a case report

    Meng, Xiaoli   Zhang, Hongqi   Chen, Yanfei   Ling, Feng  

    Spinal perimedullary arteriovenous fistula, a subtype of spinal arteriovenous malformation, is generally considered to be a congenital lesion by maldevelopment of the spinal vascular system. However, several cases of perimedullary arteriovenous fistula had been reported in the literature, which were thought to be acquired lesions. We presented a case of perimedullary arteriovenous fistula, which was believed to be derived from spinal cord trauma. The etiology and pathophysiology of this case were discussed, and it might provide further insight into the pathogenesis of such lesions.
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  • Research on Motion Detection and Target Contour Extraction in Wearable Video System

    Li, Yinxiang   Ling, Feng   Li, Tao   Li, Xiaoping  

    The wearable video system supports decision making through analyzing video images. Because personnel who wear the system or the object monitored is always moving; the technology of motion detection and target contour extraction used in the wearable video system are studied. First; the frequently-used algorithms for motion detection are studied; including frame difference method and background subtraction method; and an algorithm composing of those methods for motion detection is proposed. The principle using traditional snake model to extract contour is analyzed. The result of motion detection is used to auto initialize the contour of target band; and B-spline Snake model is used to extract the contour of moving object. The test achieved good results.
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  • Management of extracranial carotid artery aneurysm:A report of four cases

    Song, Gang   Jiao, Liqun   Chen, Yanfei   Wang, Yabing   Ma, Yan   Ling, Feng  

    Extracranial carotid artery aneurysm (ECAA) is an uncommon type of peripheral artery aneurysm. The treatment of this disease requires surgical intervention. Due to the limited number of large studies, the safety and efficacy of surgical and interventional management of ECAA is not well characterized. The optimum treatment has not been clearly defined. The present study reports four cases of ECAA. The patients received end-to-end anastomosis, carotid artery stents and balloon occlusion, respectively. These four cases demonstrate that ECAA may be successfully managed using end-to-end anastomosis. Furthermore, end-to-end anastomosis is a better intervention compared with endovascular treatment as it facilitates the removal of lesions under direct observation. The advantage of open surgery is the surgical repair of end-to-end anastomosis under direct observation. However, few studies have investigated the effect of the timing of resection of an aneurysm on patient outcome and the control of bleeding remains a challenge for surgeons. Therefore, the proximal and distal ends of aneurysm should be under direct observation during surgery.
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  • Pediatric thoracic SCIWORA after back bend during dance practice:a retrospective case series and analysis of trauma mechanisms

    Ren, Jian   Zeng, Gao   Ma, Yong-jie   Chen, Nan   Chen, Zan   Ling, Feng   Zhang, Hong-qi  

    The purpose of the study was to describe a unique type of low-energy traumatic pediatric thoracic spinal cord injury without radiographic abnormality (SCIWORA) after a back bend during dance practice and analyze the trauma mechanisms and treatment protocols. This was a retrospective case series from September 2007 to August 2016. The study was conducted at a tertiary medical center in Beijing, China (Xuanwu Hospital, China International Neuroscience Institute [China-INI], Capital Medical University). A total of 12 pediatric patients who had a clear traumatic history after back bend movements and had been diagnosed with thoracic SCIWORA were included. Clinical and imaging data were obtained for each patient. The follow-up data was analyzed. The traumatic mechanisms were investigated by analyzing the patients' medical history, spinal diffusion tensor imaging (DTI) and fiber tractography data. Of the 12 patients, 11 (91.7%) were younger than 8 years old. The mean age of the patients was 6.6 years. All patients had a clear traumatic history of severe thoracic spinal cord injury after performing back bend movements. The mean follow-up time was 36.5 months. During the follow-up period, 1 patient (8.3%) recovered completely, and 11 patients (91.7%) had unfavorable prognoses, including 4 (33.3%) with incomplete recovery and 7 (58.3%) with no change. Two patients underwent spinal DTI, which showed rupture of the nerve fiber bundle in the section of the injury. Back bend movements performed during dance practice may cause pediatric thoracic SCIWORA, particularly in children younger than 8 years old. We suggest that the mechanism of primary injury is the longitudinal distraction of the thoracic spine during back bend movements, which leads to violent distraction of the spinal cord and blunt injury of nerve axons, nerve cells, and small vessels. Spinal DTI may facilitate the diagnosis and prognostic evaluation of SCIWORA.
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  • Epidemiological profile of dengue in Zhejiang Province, southeast China

    Ren, Jiangping   Ling, Feng   Sun, Jimin   Gong, Zhenyu   Liu, Ying   Shi, Xuguang   Zhang, Rong   Zhai, Yujia   Chen, Enfu   Chen, Zhiping  

    Background Dengue is one of the most important vector-bore infectious diseases in China because of its drastic increase in incidence, geographic extension and profound influence on China's economy. This study aims to retrospectively uncover the epidemiological profile of dengue in Zhejiang, one of the most developed provinces in China, and to find the problem existing in dengue control and prevention. Methodology Descriptive analyses on the dengue incidence and associated factors were performed. We also identified potential space-time cluster and generated the risk map of dengue. Principal findings A total of 529 cases were reported in Zhejiang Province from 2005 to 2016, and 44.4% were imported. 67.7% of cases were 25-60 years old and the overall male-to-female sex ratio was 1.09:1. Dengue was reported all year round and 70.7% of cases occurred between August and October. Indigenous cases were only reported in the period between July to November and more than half occurred in September. Geographically, dengue was most distributed in Jinghua (3.62 per million), Shaoxing (1.00 per million) and Taizhou (0.81 per million) prefecture level cities. Outbreaks were confirmed in Yiwu, Keqiao and Huangyan counties in 2009, 2015, and 2016, respectively. 73.9% cases would seek medical advice within two days after onset and be confirmed within 9 days after onset. 75.6% would be recognized as dengue within 8 days after their first visit. The time intervals between onset and confirmation (median 7 vs 6 days; Wilcoxon rank sum test Z=3D-2.40, P=3D 0.016), first visit and confirmation (median 7 vs 6 days; Wilcoxon rank sum test Z=3D-2.59, P =3D0.009) of indigenous cases were significantly longer than those of imported ones. However, the time intervals between onset and first visit for indigenous cases was shorter (median 0 vs 1 days; Wilcoxon rank sum test Z=3D -2.10, P=3D 0.036). Fever (99.1%), fatigue (81.9), rash (63.7%), headache (67.2%) and myalgia (52.60%) were the most frequently mentioned symptoms. Conclusions Zhejiang has recently witnessed an increase in incidence and geographic extension of dengue. Timely diagnosis is important to stop local transmission and outbreak.
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  • Spatial-temporal fraction map fusion with multi-scale remotely sensed images

    Zhang, Yihang   Foody, Giles M.   Ling, Feng   Li, Xiaodong   Ge, Yong   Du, Yun   Atkinson, Peter M.  

    Given the common trade-off between the spatial and temporal resolutions of current satellite sensors, spatial-temporal data fusion methods could be applied to produce fused remotely sensed data with synthetic fine spatial resolution (FR) and high repeat frequency. Such fused data are required to provide a comprehensive understanding of Earth's surface land cover dynamics. In this research, a novel Spatial-Temporal Fraction Map Fusion (STFMF) model is proposed to produce a series of fine-spatial-temporal-resolution land cover fraction maps by fusing coarse-spatial-fine-temporal and fine-spatial-coarse-temporal fraction maps, which may be generated from multi-scale remotely sensed images. The STFMF has two main stages. First, FR fraction change maps are generated using kernel ridge regression. Second, a FR fraction map for the date of prediction is predicted using a temporal-weighted fusion model. In comparison to two established spatial-temporal fusion methods of spatial-temporal super-resolution land cover mapping model and spatial-temporal image reflectance fusion model, STFMF holds the following characteristics and advantages: (1) it takes account of the mixed pixel problem in FR remotely sensed images; (2) it directly uses the fraction maps as input, which could be generated from a range of satellite images or other suitable data sources; (3) it focuses on the estimation of fraction changes happened through time and can predict the land cover change more accurately. Experiments using synthetic multi-scale fraction maps simulated from Google Earth images, as well as synthetic and real MODIS-Landsat images were undertaken to test the performance of the proposed STFMF approach against two benchmark spatial-temporal reflectance fusion methods: the Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model (ESTARFM) and the Flexible Spatiotemporal Data Fusion (FSDAF) model. In both visual and quantitative evaluations, STFMF was able to generate more accurate FR fraction maps and provide more spatial detail than ESTARFM and FSDAF, particularly in areas with substantial land cover changes. STFMF has great potential to produce accurate time-series fraction maps with fine-spatial-temporal-resolution that can support studies of land cover dynamics at the sub-pixel scale.& nbsp;
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  • Comparison of Monitoring of Cerebral Blood Flow by c-FLOW and Transcranial Doppler in Carotid Endarterectomy

    Wang, Xu   Yang, Bin   Ma, Yan   Gao, Peng   Wang, Yabing   Chen, Yanfei   Jiao, Liqun   Ling, Feng   Zhao, Guoguang  

    OBJECTIVE: To prospectively compare the use of the cerebral blood flow monitor (c-FLOW) and transcranial Doppler (TCD) as 2 techniques for assessing brain perfusion during carotid endarterectomy. METHODS: This was a prospective, single-center, observational study. All patients were monitored using c-FLOW and TCD during the operation. Changes from baseline values of cerebral blood flow index and blood flow velocity of middle cerebral artery (V-MCA) were recorded following carotid artery clamping and unclamping. The correlation analysis was conducted for c-FLOW and TCD monitoring values. RESULTS: Seventy-three consecutive patients were enrolled from August 2015 to March 2016. No death or stroke occurred during the postoperative hospitalization. Fresh infarction was identified on magnetic resonance imaging in 17 patients. Ten patients showed a significant decrease of V-MCA following carotid clamping. A shunt was placed for only 4. The Pearson correlation index between CFI and V-MCA was 0.647 (P < 0.001). A cut-off of 21% decrease of CFI was proposed as optimal to detect intraoperative hypoperfusion. Seven patients were diagnosed as having hyperperfusion by TCD monitoring. The Pearson correlation index between CFI and V-MCA was 0.286 (P =3D 0.014). A cut-off of 15% increase of CFI following carotid unclamping was suggested as optimal to detect the postoperative hyperperfusion. CONCLUSIONS: c-FLOW could continuously and non-invasively monitor the cerebral blood flow in real-time during carotid endarterectomy and effectively detect the intraoperative hypoperfusion and postoperative hyperperfusion as defined by TCD so that it may serve as a favorable modality in future intraoperative monitoring.
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