The purpose of the study was to evaluate the effect of motion compensation by non-rigid registration combined with the Karhunen-Loeve Transform (KLT) filter on the signal to noise (SNR) and contrast-to-noise ratio (CN...The purpose of the study was to evaluate the effect of motion compensation by non-rigid registration combined with the Karhunen-Loeve Transform (KLT) filter on the signal to noise (SNR) and contrast-to-noise ratio (CNR) of hybrid gradient-echo echoplanar (GRE-EPI) first-pass myocardial perfusion imaging. Twenty one consecutive first-pass adenosine stress perfusion MR data sets interpreted positive for ischemia or infarction were processed by non-rigid Registration followed by KLT filtering. SNR and CNR were measured in abnormal and normal myocardium in unfiltered and KLT filtered images following nonrigid registration to compensate for respiratory and other motions. Image artifacts introduced by filtering in registered and nonregistered images were evaluated by two observers. There was a statistically sig- nificant increase in both SNR and CNR between normal and abnormal myocardium with KLT filtering (mean SNR increased by 62.18% ± 21.05% and mean CNR increased by 58.84% ± 18.06%;p = 0.01). Motion correction prior to KLT filtering reduced significantly the occurrence of filter induced artifacts (KLT only-artifacts in 42 out of 55 image series vs. registered plus KLT-artifacts in 3 out of 55 image series). In conclusion the combination of non-rigid registration and KLT filtering was shown to increase the SNR and CNR of GRE-EPI perfusion images. Subjective evaluation of image artifacts revealed that prior motion compensation significantly reduced the artifacts introduced by the KLT filtering process.展开更多
The one-dimensional carbon nanotubes/nanorods(CNT/CNR)mixed nano-carbon material was successfully prepared by halloysite nanotubes(HNTs)as the template for the first time,in which CNT was formed through PVA modificati...The one-dimensional carbon nanotubes/nanorods(CNT/CNR)mixed nano-carbon material was successfully prepared by halloysite nanotubes(HNTs)as the template for the first time,in which CNT was formed through PVA modification in internal surface of HNTs and CNR was obtained by nanocasting PVA in hollow nanostructure of HNTs.The CNT of the mixture with flexible structure has ca.20 nm in pore diameter and ca.500 nm in length,whereas the CNR with hard and solid structure shows ca.30 nm in diameter and ca.2μm in length.For application as fillers,the CNT/CNR mixed nano-material is used to reinforce the properties of polytetrafluoroethylene(PTFE).The mechanical and tribological properties of PTFE nanocomposites were intensively examined by a series of testing.The ring-on-ring counterface was used to evaluate the tribological behavior of the nanocomposites.The results showed that the volume wear rate of the CNT/CNR-reinforced PTFE nanocomposite after being filled with 0.3%of CNT/CNR was only 1/700 of that of the pure PTFE under a load of 200 N and a rotary speed of 200 r/min,while other mechanical and tribological performance was comparable to the performance of pure PTFE,which exhibited a desirable application prospect.展开更多
Wireless Sensor Networks(WSNs)are an integral part of the Internet of Things(IoT)and are widely used in a plethora of applications.Typically,sensor networks operate in harsh environments where human intervention is of...Wireless Sensor Networks(WSNs)are an integral part of the Internet of Things(IoT)and are widely used in a plethora of applications.Typically,sensor networks operate in harsh environments where human intervention is often restricted,which makes battery replacement for sensor nodes impractical.Node failure due to battery drainage or harsh environmental conditions poses serious challenges to the connectivity of the network.Without a connectivity restoration mechanism,node failures ultimately lead to a network partition,which affects the basic function of the sensor network.Therefore,the research community actively concentrates on addressing and solving the challenges associated with connectivity restoration in sensor networks.Since energy is a scarce resource in sensor networks,it becomes the focus of research,and researchers strive to propose new solutions that are energy efficient.The common issue that is well studied and considered is how to increase the network’s life span by solving the node failure problem and achieving efficient energy utilization.This paper introduces a Clusterbased Node Recovery(CNR)connectivity restoration mechanism based on the concept of clustering.Clustering is a well-known mechanism in sensor networks,and it is known for its energy-efficient operation and scalability.The proposed technique utilizes a distributed cluster-based approach to identify the failed nodes,while Cluster Heads(CHs)play a significant role in the restoration of connectivity.Extensive simulations were conducted to evaluate the performance of the proposed technique and compare it with the existing techniques.The simulation results show that the proposed technique efficiently addresses node failure and restores connectivity by moving fewer nodes than other existing connectivity restoration mechanisms.The proposed mechanism also yields an improved field coverage as well as a lesser number of packets exchanged as compared to existing state-of-the-art mechanisms.展开更多
LeSPL-CNR is a crucial transcription factor for fruit ripening of Solanum lycopersicum. The cnr (colorless non-ripening) epimutation resulted from hypermethylation in a 286 bp region of LeSPL-CNR promoter inhibits nor...LeSPL-CNR is a crucial transcription factor for fruit ripening of Solanum lycopersicum. The cnr (colorless non-ripening) epimutation resulted from hypermethylation in a 286 bp region of LeSPL-CNR promoter inhibits normal fruit ripening. In present study, potential regulators of LeSPL-CNR, which could bind to the specific 286 bp region, were screened via south-western blotting and yeast one-hybrid (Y1H) library screening system. Results indicated that a total of 13 and 19 candidate proteins were acquired respectively, and both ribulose-1,5-bisphosphate carboxylase/oxygenase and 40S ribosomal protein were identified by two methods. These would provide some information for revealing roles of DNA methylation and the regulatory mechanism for LeSPL-CNR.展开更多
文摘The purpose of the study was to evaluate the effect of motion compensation by non-rigid registration combined with the Karhunen-Loeve Transform (KLT) filter on the signal to noise (SNR) and contrast-to-noise ratio (CNR) of hybrid gradient-echo echoplanar (GRE-EPI) first-pass myocardial perfusion imaging. Twenty one consecutive first-pass adenosine stress perfusion MR data sets interpreted positive for ischemia or infarction were processed by non-rigid Registration followed by KLT filtering. SNR and CNR were measured in abnormal and normal myocardium in unfiltered and KLT filtered images following nonrigid registration to compensate for respiratory and other motions. Image artifacts introduced by filtering in registered and nonregistered images were evaluated by two observers. There was a statistically sig- nificant increase in both SNR and CNR between normal and abnormal myocardium with KLT filtering (mean SNR increased by 62.18% ± 21.05% and mean CNR increased by 58.84% ± 18.06%;p = 0.01). Motion correction prior to KLT filtering reduced significantly the occurrence of filter induced artifacts (KLT only-artifacts in 42 out of 55 image series vs. registered plus KLT-artifacts in 3 out of 55 image series). In conclusion the combination of non-rigid registration and KLT filtering was shown to increase the SNR and CNR of GRE-EPI perfusion images. Subjective evaluation of image artifacts revealed that prior motion compensation significantly reduced the artifacts introduced by the KLT filtering process.
基金funded by the Talent Introduction Fund of Yangzhou University(2012)the Zhenjiang High Technology Research Institute of Yangzhou University(2017)+5 种基金the Key Research Project-Industry Foresight and General Key Technology of Yangzhou(YZ2015020)the Innovative Talent Program of Green Yang Golden Phoenix(yzlyjfjh2015CX073)the Yangzhou Social Development Project(YZ2016072)the Jiangsu Province Six Talent Peaks Project(2014-XCL-013)the Jiangsu Industrial-Academic-Research Prospective Joint Project(BY2016069-02)the Priority Academic Program Development of Jiangsu Higher Education Institutions and Top-notch Academic Programs Project of Jiangsu Higher Education Institutions(PPZY2015B112)for the financial support
文摘The one-dimensional carbon nanotubes/nanorods(CNT/CNR)mixed nano-carbon material was successfully prepared by halloysite nanotubes(HNTs)as the template for the first time,in which CNT was formed through PVA modification in internal surface of HNTs and CNR was obtained by nanocasting PVA in hollow nanostructure of HNTs.The CNT of the mixture with flexible structure has ca.20 nm in pore diameter and ca.500 nm in length,whereas the CNR with hard and solid structure shows ca.30 nm in diameter and ca.2μm in length.For application as fillers,the CNT/CNR mixed nano-material is used to reinforce the properties of polytetrafluoroethylene(PTFE).The mechanical and tribological properties of PTFE nanocomposites were intensively examined by a series of testing.The ring-on-ring counterface was used to evaluate the tribological behavior of the nanocomposites.The results showed that the volume wear rate of the CNT/CNR-reinforced PTFE nanocomposite after being filled with 0.3%of CNT/CNR was only 1/700 of that of the pure PTFE under a load of 200 N and a rotary speed of 200 r/min,while other mechanical and tribological performance was comparable to the performance of pure PTFE,which exhibited a desirable application prospect.
基金This research is funded by Najran University Saudi Arabia,under the research Project Number(NU/ESCI/17/093).URL:www.nu.edu.sa。
文摘Wireless Sensor Networks(WSNs)are an integral part of the Internet of Things(IoT)and are widely used in a plethora of applications.Typically,sensor networks operate in harsh environments where human intervention is often restricted,which makes battery replacement for sensor nodes impractical.Node failure due to battery drainage or harsh environmental conditions poses serious challenges to the connectivity of the network.Without a connectivity restoration mechanism,node failures ultimately lead to a network partition,which affects the basic function of the sensor network.Therefore,the research community actively concentrates on addressing and solving the challenges associated with connectivity restoration in sensor networks.Since energy is a scarce resource in sensor networks,it becomes the focus of research,and researchers strive to propose new solutions that are energy efficient.The common issue that is well studied and considered is how to increase the network’s life span by solving the node failure problem and achieving efficient energy utilization.This paper introduces a Clusterbased Node Recovery(CNR)connectivity restoration mechanism based on the concept of clustering.Clustering is a well-known mechanism in sensor networks,and it is known for its energy-efficient operation and scalability.The proposed technique utilizes a distributed cluster-based approach to identify the failed nodes,while Cluster Heads(CHs)play a significant role in the restoration of connectivity.Extensive simulations were conducted to evaluate the performance of the proposed technique and compare it with the existing techniques.The simulation results show that the proposed technique efficiently addresses node failure and restores connectivity by moving fewer nodes than other existing connectivity restoration mechanisms.The proposed mechanism also yields an improved field coverage as well as a lesser number of packets exchanged as compared to existing state-of-the-art mechanisms.
文摘LeSPL-CNR is a crucial transcription factor for fruit ripening of Solanum lycopersicum. The cnr (colorless non-ripening) epimutation resulted from hypermethylation in a 286 bp region of LeSPL-CNR promoter inhibits normal fruit ripening. In present study, potential regulators of LeSPL-CNR, which could bind to the specific 286 bp region, were screened via south-western blotting and yeast one-hybrid (Y1H) library screening system. Results indicated that a total of 13 and 19 candidate proteins were acquired respectively, and both ribulose-1,5-bisphosphate carboxylase/oxygenase and 40S ribosomal protein were identified by two methods. These would provide some information for revealing roles of DNA methylation and the regulatory mechanism for LeSPL-CNR.
