BACKGROUND Four-corner fusion(4CF)is a motion sparing salvage procedure that is used to treat osteoarthritis secondary to advanced scapholunate collapse or longstanding scaphoid nonunion advanced collapse.Little is kn...BACKGROUND Four-corner fusion(4CF)is a motion sparing salvage procedure that is used to treat osteoarthritis secondary to advanced scapholunate collapse or longstanding scaphoid nonunion advanced collapse.Little is known about the long-term survivorship and outcomes of 4CF.AIM To report on clinical and functional long-term outcomes as well as conversion rates to total wrist fusion or arthroplasty.METHODS The systematic review protocol was registered in the international prospective register of systematic reviews(PROSPERO)and followed the PRISMA guidelines.Original articles were screened using four different databases.Studies with a minimum Level IV of evidence that reported on long-term outcome after 4CF with a minimum follow-up of 5 years were included.Quality assessment was performed using the Methodological Index for Non-Randomized Studies criteria.RESULTS A total of 11 studies including 436 wrists with a mean follow-up of 11±4 years(range:6-18 years)was included.Quality assessment according to Methodological Index for Non-Randomized Studies criteria tool averaged 69%±11%(range:50%-87%).Fusion rate could be extracted from 9/11 studies and averaged 91%.Patient-reported outcomes were extracted at last follow-up from 8 studies with an average visual analog scale of 1±1(range:0-2)and across 9 studies with an average Disabilities of the Arm,Shoulder and Hand score of 21±8(range:8-37).At last follow-up,the cumulative conversion rate to total wrist fusion averaged 6%.There were no conversions to total wrist arthroplasty.CONCLUSION The 4CF of the wrist is a reliable surgical technique,capable of achieving a good long-term patient satisfaction and survivorship with low rates of conversion to total wrist fusion.展开更多
Low-NOX combustion retrofit is performed by adopting staged combustion technology for a 600 MW utility boiler with a four-corner tangential firing system. The emission data of NOX before and after retrofit are compare...Low-NOX combustion retrofit is performed by adopting staged combustion technology for a 600 MW utility boiler with a four-corner tangential firing system. The emission data of NOX before and after retrofit are compared and analyzed. The test results show that the emission concentration of NOX decreases obviously after the low-NOX retrofit. Additionally, the emission of NOX decreases by nearly 50% when the unit load is higher than 350 MW. It can also be concluded that the emission of NOX is influenced significantly by the amount of SOFA, the damper opening of auxiliary air, the differential pressure between the secondary air windbox and the furnace, and so on.展开更多
To address the incomplete problem in pulmonary parenchyma segmentation based on the traditional methods, a novel automated segmentation method based on an eight- neighbor region growing algorithm with left-right scann...To address the incomplete problem in pulmonary parenchyma segmentation based on the traditional methods, a novel automated segmentation method based on an eight- neighbor region growing algorithm with left-right scanning and four-corner rotating and scanning is proposed in this pa- per. The proposed method consists of four main stages： image binarization, rough segmentation of lung, image denoising and lung contour refining. First, the binarization of images is done and the regions of interest are extracted. After that, the rough segmentation of lung is performed through a general region growing method. Then the improved eight-neighbor region growing is used to remove noise for the upper, mid- dle, and bottom region of lung. Finally, corrosion and ex- pansion operations are utilized to smooth the lung boundary. The proposed method was validated on chest positron emis- sion tomography-computed tomography （PET-CT） data of 30 cases from a hospital in Shanxi, China. Experimental results show that our method can achieve an average volume overlap ratio of 96.21 ± 0.39% with the manual segmentation results. Compared with the existing methods, the proposed algorithm segments the lung in PET-CT images more efficiently and ac- curately.展开更多
文摘BACKGROUND Four-corner fusion(4CF)is a motion sparing salvage procedure that is used to treat osteoarthritis secondary to advanced scapholunate collapse or longstanding scaphoid nonunion advanced collapse.Little is known about the long-term survivorship and outcomes of 4CF.AIM To report on clinical and functional long-term outcomes as well as conversion rates to total wrist fusion or arthroplasty.METHODS The systematic review protocol was registered in the international prospective register of systematic reviews(PROSPERO)and followed the PRISMA guidelines.Original articles were screened using four different databases.Studies with a minimum Level IV of evidence that reported on long-term outcome after 4CF with a minimum follow-up of 5 years were included.Quality assessment was performed using the Methodological Index for Non-Randomized Studies criteria.RESULTS A total of 11 studies including 436 wrists with a mean follow-up of 11±4 years(range:6-18 years)was included.Quality assessment according to Methodological Index for Non-Randomized Studies criteria tool averaged 69%±11%(range:50%-87%).Fusion rate could be extracted from 9/11 studies and averaged 91%.Patient-reported outcomes were extracted at last follow-up from 8 studies with an average visual analog scale of 1±1(range:0-2)and across 9 studies with an average Disabilities of the Arm,Shoulder and Hand score of 21±8(range:8-37).At last follow-up,the cumulative conversion rate to total wrist fusion averaged 6%.There were no conversions to total wrist arthroplasty.CONCLUSION The 4CF of the wrist is a reliable surgical technique,capable of achieving a good long-term patient satisfaction and survivorship with low rates of conversion to total wrist fusion.
文摘Low-NOX combustion retrofit is performed by adopting staged combustion technology for a 600 MW utility boiler with a four-corner tangential firing system. The emission data of NOX before and after retrofit are compared and analyzed. The test results show that the emission concentration of NOX decreases obviously after the low-NOX retrofit. Additionally, the emission of NOX decreases by nearly 50% when the unit load is higher than 350 MW. It can also be concluded that the emission of NOX is influenced significantly by the amount of SOFA, the damper opening of auxiliary air, the differential pressure between the secondary air windbox and the furnace, and so on.
文摘To address the incomplete problem in pulmonary parenchyma segmentation based on the traditional methods, a novel automated segmentation method based on an eight- neighbor region growing algorithm with left-right scanning and four-corner rotating and scanning is proposed in this pa- per. The proposed method consists of four main stages： image binarization, rough segmentation of lung, image denoising and lung contour refining. First, the binarization of images is done and the regions of interest are extracted. After that, the rough segmentation of lung is performed through a general region growing method. Then the improved eight-neighbor region growing is used to remove noise for the upper, mid- dle, and bottom region of lung. Finally, corrosion and ex- pansion operations are utilized to smooth the lung boundary. The proposed method was validated on chest positron emis- sion tomography-computed tomography （PET-CT） data of 30 cases from a hospital in Shanxi, China. Experimental results show that our method can achieve an average volume overlap ratio of 96.21 ± 0.39% with the manual segmentation results. Compared with the existing methods, the proposed algorithm segments the lung in PET-CT images more efficiently and ac- curately.
