Sphingolipids have been suggested to act as second messengers for an array of cellular signaling activities in plant cells, including stress responses and programmed cell death （PCD）. However, the mechanisms underpi...Sphingolipids have been suggested to act as second messengers for an array of cellular signaling activities in plant cells, including stress responses and programmed cell death （PCD）. However, the mechanisms underpinning these processes are not well understood. Here, we report that an Arabidopsis mutant, fumonisin B1 r_esistant11-1 （/br11-1）, which fails to generate reactive oxygen intermediates （ROIs）, is incapable of initiating PCD when the mutant is challenged by fumonisin B l （FB0, a specific inhibitor of ceramide synthase. Molecular analysis indicated that FBR11 encodes a long-chain base 1 （LCB 1） subunit of serine palmitoyltransferase （SPT）, which catalyzes the first rate-limiting step of de novo sphingolipid synthesis. Mass spectrometric analysis of the sphingolipid concentrations revealed that whereas the fbr11-1 mutation did not affect basal levels of sphingoid bases, the mutant showed attenuated formation of sphingoid bases in response to FBl. By a direct feeding experiment, we show that the free sphingoid bases dihydrosphingosine, phytosphingosine and sphingosine efficiently induce ROI generation followed by cell death. Conversely, ROI generation and cell death induced by dihydrosphingosine were specifically blocked by its phosphorylated form dihydrosphingosine- 1-phosphate in a dosedependent manner, suggesting that the maintenance of homeostasis between a free sphingoid base and its phosphorylated derivative is critical to determining the cell fate. Because alterations of the sphingolipid level occur prior to the ROI production, we propose that the free sphingoid bases are involved in the control of PCD in Arabidopsis, presumably through the regulation of the ROI level upon receiving different developmental or environmental cues.展开更多
A new scheme named personalized image retrieval technique based on visual perception is proposed in this letter, whose motive is to narrow the semantic gap by directly perceiving user's visual information. It uses...A new scheme named personalized image retrieval technique based on visual perception is proposed in this letter, whose motive is to narrow the semantic gap by directly perceiving user's visual information. It uses visual attention model to segment image regions and eye-tracking technique to record fixations. Visual perception is obtained by analyzing the fixations in regions to measure gaze interests. Integrating visual perception into attention model is to detect the Regions Of Interest (ROIs), whose features are extracted and analyzed, then feedback interests to optimize the results and construct user profiles.展开更多
Plantar Region of Interest （ROI） detection is important for the early diagnosis and treatment ofmorphologic defects of the foot and foot bionic research. Conventional methods have employed complex procedures and exp...Plantar Region of Interest （ROI） detection is important for the early diagnosis and treatment ofmorphologic defects of the foot and foot bionic research. Conventional methods have employed complex procedures and expensive instruments which prohibit their widespread use in healthcare. In this paper an automatic plantar ROIs detection method using a customized low-cost pressure acquisition device is proposed. Plantar pressure data and 3D motion capture data were collected from 28 subjects （14 healthy subjects and 14 subjects with hallux valgus）. The maximal inter-frame difference during the stance phase was calculated. Consequently, the ROIs were defined by the first-order difference in combination with prior anatomic knowl- edge. The anatomic locations were determined by the maximal inter-frame difference and second maximal inter-frame differ- ence, which nearly coincided. Our system can achieve average recognition accuracies of 92.90%, 89.30%, 89.30%, 92.90%, 92.90%, and 89.30% for plantar ROIs hallux and metatarsi I-V, respectively, as compared with the annotations using the 3D motion capture system. The maximal difference of metatarsus heads II-V, and the impulse of the medial and lateral heel features made a significant contribution to the classification ofhallux valgus and healthy subjects with ≥ 80% sensitivity and specificity. Furthermore, the plantar pressure acquisition system is portable and convenient to use, thus can be used in home- or commu- nity-based healthcare applications.展开更多
感兴趣区域（regions of interest,ROIs）的选择及其光谱提取是高光谱图像无损检测分析的关键一步。为快速准确检测羊肉pH,在473～1 000nm波段,开展了两种不同提取ROIs方法对羊肉pH高光谱检测模型的影响研究。采用＂矩形区域法＂和＂图...感兴趣区域（regions of interest,ROIs）的选择及其光谱提取是高光谱图像无损检测分析的关键一步。为快速准确检测羊肉pH,在473～1 000nm波段,开展了两种不同提取ROIs方法对羊肉pH高光谱检测模型的影响研究。采用＂矩形区域法＂和＂图像分割法＂两种ROIs方法分别获得相应的122条羊肉光谱,对比了不同预处理方法对建模效果的影响,并比较了两种ROIs方法下逐步多元线性回归（SMLR）、主成分回归（PCR）和偏最小二乘回归（PLSR）的模型精度。结果表明,提取光谱数据建模中SMLR和PLSR模型效果分别最优。＂矩形区域法＂提取ROIs对应的SMLR模型校正集的相关系数（R_（cal））和均方根误差（RMSEC）分别为0.85和0.085,预测集的相关系数（R_p）和均方根误差（RMSEP）分别为0.82和0.097。＂图像分割法＂提取ROIs对应的PLSR模型校正集的Rcal和RMSEC分别为0.95和0.050,预测集的Rp和RMSEP分别为0.91和0.071。其次通过比较＂矩形区域法＂和PCR,SMLR和PLSR三个模型中,＂图像分割法＂提取的ROIs光谱数据建模效果较优。表明,应用高光谱图像技术结合＂图像分割法＂提取ROIs快速无损准确检测羊肉pH具有可行性。展开更多
基金Acknowledgments We would like to thank the Arabidopsis Biological Resources Center （Ohio State University, USA） for providing seeds and Dr Teresa Dunn （Uniformed Services University of the Health Sciences, USA） for providing yeast strains. We are grateful to Drs Weicai Yang, Yongbiao Xue （Institute of Genetics and Developmental Biology, Chinese Academy of Sciences） and De Ye （China Agriculture University） for critical reading of the manuscript. This work was supported by grants from the National Natural Science Foundation of China （30330360, 30125025 and 30221002） and the Chinese Academy of Sciences to Jianru Zuo.
文摘Sphingolipids have been suggested to act as second messengers for an array of cellular signaling activities in plant cells, including stress responses and programmed cell death （PCD）. However, the mechanisms underpinning these processes are not well understood. Here, we report that an Arabidopsis mutant, fumonisin B1 r_esistant11-1 （/br11-1）, which fails to generate reactive oxygen intermediates （ROIs）, is incapable of initiating PCD when the mutant is challenged by fumonisin B l （FB0, a specific inhibitor of ceramide synthase. Molecular analysis indicated that FBR11 encodes a long-chain base 1 （LCB 1） subunit of serine palmitoyltransferase （SPT）, which catalyzes the first rate-limiting step of de novo sphingolipid synthesis. Mass spectrometric analysis of the sphingolipid concentrations revealed that whereas the fbr11-1 mutation did not affect basal levels of sphingoid bases, the mutant showed attenuated formation of sphingoid bases in response to FBl. By a direct feeding experiment, we show that the free sphingoid bases dihydrosphingosine, phytosphingosine and sphingosine efficiently induce ROI generation followed by cell death. Conversely, ROI generation and cell death induced by dihydrosphingosine were specifically blocked by its phosphorylated form dihydrosphingosine- 1-phosphate in a dosedependent manner, suggesting that the maintenance of homeostasis between a free sphingoid base and its phosphorylated derivative is critical to determining the cell fate. Because alterations of the sphingolipid level occur prior to the ROI production, we propose that the free sphingoid bases are involved in the control of PCD in Arabidopsis, presumably through the regulation of the ROI level upon receiving different developmental or environmental cues.
基金Supported by the National Natural Science Foundation of China (No.60472036, No.60431020, No.60402036)the Natural Science Foundation of Beijing (No.4042008)and Ph.D. Foundation of Ministry of Education (No.20040005015).
文摘A new scheme named personalized image retrieval technique based on visual perception is proposed in this letter, whose motive is to narrow the semantic gap by directly perceiving user's visual information. It uses visual attention model to segment image regions and eye-tracking technique to record fixations. Visual perception is obtained by analyzing the fixations in regions to measure gaze interests. Integrating visual perception into attention model is to detect the Regions Of Interest (ROIs), whose features are extracted and analyzed, then feedback interests to optimize the results and construct user profiles.
基金Acknowledgments This study was financed, in part, by the National Natural Science Foundation of China （Grant Nos. 60932001, 61072031, and 51105359）, the National Ba- sic Research （973） Program of China （Sub-grant 6 of Grant No. 2010CB732606）, and the Knowledge Inno- vation Program of the Chinese Academy of Sciences, and was also supported by the Guangdong Innovation Research Team Fund for Low-cost Healthcare Tech- nologies and the China Postdoctoral Science Foundation （Grant No. 2011M500402）.
文摘Plantar Region of Interest （ROI） detection is important for the early diagnosis and treatment ofmorphologic defects of the foot and foot bionic research. Conventional methods have employed complex procedures and expensive instruments which prohibit their widespread use in healthcare. In this paper an automatic plantar ROIs detection method using a customized low-cost pressure acquisition device is proposed. Plantar pressure data and 3D motion capture data were collected from 28 subjects （14 healthy subjects and 14 subjects with hallux valgus）. The maximal inter-frame difference during the stance phase was calculated. Consequently, the ROIs were defined by the first-order difference in combination with prior anatomic knowl- edge. The anatomic locations were determined by the maximal inter-frame difference and second maximal inter-frame differ- ence, which nearly coincided. Our system can achieve average recognition accuracies of 92.90%, 89.30%, 89.30%, 92.90%, 92.90%, and 89.30% for plantar ROIs hallux and metatarsi I-V, respectively, as compared with the annotations using the 3D motion capture system. The maximal difference of metatarsus heads II-V, and the impulse of the medial and lateral heel features made a significant contribution to the classification ofhallux valgus and healthy subjects with ≥ 80% sensitivity and specificity. Furthermore, the plantar pressure acquisition system is portable and convenient to use, thus can be used in home- or commu- nity-based healthcare applications.
文摘感兴趣区域（regions of interest,ROIs）的选择及其光谱提取是高光谱图像无损检测分析的关键一步。为快速准确检测羊肉pH,在473～1 000nm波段,开展了两种不同提取ROIs方法对羊肉pH高光谱检测模型的影响研究。采用＂矩形区域法＂和＂图像分割法＂两种ROIs方法分别获得相应的122条羊肉光谱,对比了不同预处理方法对建模效果的影响,并比较了两种ROIs方法下逐步多元线性回归（SMLR）、主成分回归（PCR）和偏最小二乘回归（PLSR）的模型精度。结果表明,提取光谱数据建模中SMLR和PLSR模型效果分别最优。＂矩形区域法＂提取ROIs对应的SMLR模型校正集的相关系数（R_（cal））和均方根误差（RMSEC）分别为0.85和0.085,预测集的相关系数（R_p）和均方根误差（RMSEP）分别为0.82和0.097。＂图像分割法＂提取ROIs对应的PLSR模型校正集的Rcal和RMSEC分别为0.95和0.050,预测集的Rp和RMSEP分别为0.91和0.071。其次通过比较＂矩形区域法＂和PCR,SMLR和PLSR三个模型中,＂图像分割法＂提取的ROIs光谱数据建模效果较优。表明,应用高光谱图像技术结合＂图像分割法＂提取ROIs快速无损准确检测羊肉pH具有可行性。
