Objective To evaluate the feasibility and accuracy of measurement of myocardial perfusion defects with intravenous contrast-enhanced real-time three-dimensional echocardiography (CE-RT3DE). Methods RT3DE was performed...Objective To evaluate the feasibility and accuracy of measurement of myocardial perfusion defects with intravenous contrast-enhanced real-time three-dimensional echocardiography (CE-RT3DE). Methods RT3DE was performed in 21 open-chest mongrel dogs undergoing acute ligation of the left anterior descending artery (LAD, n=14) or distal branch of the left circumflex artery (LCX, n=7). A perfluorocarbon microbubble contrast agent was injected intravenously to assess the resulting myocardial perfusion defects with Philips Sonos-7500 ultrasound system. Evans blue dye was injected into the occluded coronary artery for subsequent anatomic identification of underperfused myocardium. In vitro anatomic measurement of myocardial mass after removal of the animal’s heart was regarded as the control. Blinded off-line calculation of left ventricular mass and perfusion defect mass from RT3DE images were performed using an interactive aided-manual tracing technique.Results Total left ventricular (LV) myocardial mass ranged from 38.9 to 78.5 (mean±SD: 60.0±10.1) g. The mass of perfusion defect ranged from 0 to 21.4 (mean±SD: 12.0±5.0) g or 0 to 27% of total LV mass (mean±SD: 19%±6%). The RT3DE estimation of total LV mass (mean±SD: 59.8±9.9 g) strongly correlated with the anatomic measurement (r=0.98; y=2.01+0.96x). The CE-RT3DE calculation of the mass of underperfused myocardium (mean±SD: 12.3±5.3 g) also strongly correlated with the anatomic measurement (r=0.96; y=-0.10+1.04x) and when expressed as percentage of total LV mass (r=0.95; y=-0.20+1.04x). Conclusions RT3DE with myocardial contrast opacification could accurately estimate underperfused myocardial mass in dogs of acute coronary occlusion and would play an important role in quantitative assessment of myocardial perfusion defects in patients with coronary artery disease.展开更多
The correct rate of detection for fabric defect is affected by low contrast of images. Aiming at the problem,frequencytuned salient map is used to detect the fabric defect. Firstly,the images of fabric defect are divi...The correct rate of detection for fabric defect is affected by low contrast of images. Aiming at the problem,frequencytuned salient map is used to detect the fabric defect. Firstly,the images of fabric defect are divided into blocks. Then,the blocks are highlighted by frequency-tuned salient algorithm. Simultaneously,gray-level co-occurrence matrix is used to extract the characteristic value of each rectangular patch. Finally,PNN is used to detect the defect on the fabric image. The performance of proposed algorithm is estimated off-line by two sets of fabric defect images. The theoretical argument is supported by experimental results.展开更多
We investigate the effects of strain on the electronic and magnetic properties of ReS2 monolayer with sulfur vacancies using density functional theory.Unstrained ReS2 monolayer with monosulfur vacancy（Vs） and disulf...We investigate the effects of strain on the electronic and magnetic properties of ReS2 monolayer with sulfur vacancies using density functional theory.Unstrained ReS2 monolayer with monosulfur vacancy（Vs） and disulfur vacancy（V（2S））both are nonmagnetic.However,as strain increases to 8%,VS-doped ReS2 monolayer appears a magnetic half-metal behavior with zero total magnetic moment.In particular,for V（2S）-doped ReS2 monolayer,the system becomes a magnetic semiconductor under 6%strain,in which Re atoms at vicinity of vacancy couple anti-ferromagnetically with each other,and continues to show a ferromagnetic metal characteristic with total magnetic moment of 1.60μb under 7%strain.Our results imply that the strain-manipulated ReS2 monolayer with VS and V（2S） can be a possible candidate for new spintronic applications.展开更多
Compared with non-degradable materials,biodegradable biomaterials play an increasingly important role in the repairing of severe bone defects,and have attracted extensive attention from researchers.In the treatment of...Compared with non-degradable materials,biodegradable biomaterials play an increasingly important role in the repairing of severe bone defects,and have attracted extensive attention from researchers.In the treatment of bone defects,scaffolds made of biodegradable materials can provide a crawling bridge for new bone tissue in the gap and a platform for cells and growth factors to play a physiological role,which will eventually be degraded and absorbed in the body and be replaced by the new bone tissue.Traditional biodegradable materials include polymers,ceramics and metals,which have been used in bone defect repairing for many years.Although these materials have more or fewer shortcomings,they are still the cornerstone of our development of a new generation of degradable materials.With the rapid development of modern science and technology,in the 21 st century,more and more kinds of new biodegradable materials emerge in endlessly,such as new intelligent micro-nano materials and cell-based products.At the same time,there are many new fabrication technologies of improving biodegradable materials,such as modular fabrication,3 D and 4 D printing,interface reinforcement and nanotechnology.This review will introduce various kinds of biodegradable materials commonly used in bone defect repairing,especially the newly emerging materials and their fabrication technology in recent years,and look forward to the future research direction,hoping to provide researchers in the field with some inspiration and reference.展开更多
文摘Objective To evaluate the feasibility and accuracy of measurement of myocardial perfusion defects with intravenous contrast-enhanced real-time three-dimensional echocardiography (CE-RT3DE). Methods RT3DE was performed in 21 open-chest mongrel dogs undergoing acute ligation of the left anterior descending artery (LAD, n=14) or distal branch of the left circumflex artery (LCX, n=7). A perfluorocarbon microbubble contrast agent was injected intravenously to assess the resulting myocardial perfusion defects with Philips Sonos-7500 ultrasound system. Evans blue dye was injected into the occluded coronary artery for subsequent anatomic identification of underperfused myocardium. In vitro anatomic measurement of myocardial mass after removal of the animal’s heart was regarded as the control. Blinded off-line calculation of left ventricular mass and perfusion defect mass from RT3DE images were performed using an interactive aided-manual tracing technique.Results Total left ventricular (LV) myocardial mass ranged from 38.9 to 78.5 (mean±SD: 60.0±10.1) g. The mass of perfusion defect ranged from 0 to 21.4 (mean±SD: 12.0±5.0) g or 0 to 27% of total LV mass (mean±SD: 19%±6%). The RT3DE estimation of total LV mass (mean±SD: 59.8±9.9 g) strongly correlated with the anatomic measurement (r=0.98; y=2.01+0.96x). The CE-RT3DE calculation of the mass of underperfused myocardium (mean±SD: 12.3±5.3 g) also strongly correlated with the anatomic measurement (r=0.96; y=-0.10+1.04x) and when expressed as percentage of total LV mass (r=0.95; y=-0.20+1.04x). Conclusions RT3DE with myocardial contrast opacification could accurately estimate underperfused myocardial mass in dogs of acute coronary occlusion and would play an important role in quantitative assessment of myocardial perfusion defects in patients with coronary artery disease.
文摘The correct rate of detection for fabric defect is affected by low contrast of images. Aiming at the problem,frequencytuned salient map is used to detect the fabric defect. Firstly,the images of fabric defect are divided into blocks. Then,the blocks are highlighted by frequency-tuned salient algorithm. Simultaneously,gray-level co-occurrence matrix is used to extract the characteristic value of each rectangular patch. Finally,PNN is used to detect the defect on the fabric image. The performance of proposed algorithm is estimated off-line by two sets of fabric defect images. The theoretical argument is supported by experimental results.
基金Project supported by the National Natural Science Foundation of China(Grant No.11547030)
文摘We investigate the effects of strain on the electronic and magnetic properties of ReS2 monolayer with sulfur vacancies using density functional theory.Unstrained ReS2 monolayer with monosulfur vacancy（Vs） and disulfur vacancy（V（2S））both are nonmagnetic.However,as strain increases to 8%,VS-doped ReS2 monolayer appears a magnetic half-metal behavior with zero total magnetic moment.In particular,for V（2S）-doped ReS2 monolayer,the system becomes a magnetic semiconductor under 6%strain,in which Re atoms at vicinity of vacancy couple anti-ferromagnetically with each other,and continues to show a ferromagnetic metal characteristic with total magnetic moment of 1.60μb under 7%strain.Our results imply that the strain-manipulated ReS2 monolayer with VS and V（2S） can be a possible candidate for new spintronic applications.
基金supported by grants from the National Natural Science Foundation of China(11772226,81871777 and 81572154)the Tianjin Science and Technology Plan Project(18PTLCSY00070,16ZXZNGX00130)grants awarded to Xiao-Song Gu by the National Natural Science Foundation of China(31730031 and L1924064)。
文摘Compared with non-degradable materials,biodegradable biomaterials play an increasingly important role in the repairing of severe bone defects,and have attracted extensive attention from researchers.In the treatment of bone defects,scaffolds made of biodegradable materials can provide a crawling bridge for new bone tissue in the gap and a platform for cells and growth factors to play a physiological role,which will eventually be degraded and absorbed in the body and be replaced by the new bone tissue.Traditional biodegradable materials include polymers,ceramics and metals,which have been used in bone defect repairing for many years.Although these materials have more or fewer shortcomings,they are still the cornerstone of our development of a new generation of degradable materials.With the rapid development of modern science and technology,in the 21 st century,more and more kinds of new biodegradable materials emerge in endlessly,such as new intelligent micro-nano materials and cell-based products.At the same time,there are many new fabrication technologies of improving biodegradable materials,such as modular fabrication,3 D and 4 D printing,interface reinforcement and nanotechnology.This review will introduce various kinds of biodegradable materials commonly used in bone defect repairing,especially the newly emerging materials and their fabrication technology in recent years,and look forward to the future research direction,hoping to provide researchers in the field with some inspiration and reference.
