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Objectives: Patients undergoing a prior failed attempt of chronic total occlusion‐percutaneous coronary intervention (CTO‐PCI) represent a challenging subgroup across all patients undergoing CTO‐PCI. There are limited data on the effects of a prior failed attempt on the outcomes of subsequent CTO‐PCI. We aimed to compare the procedural results and 24‐month outcomes of prior‐failed‐attempt CTO‐PCI with those of initial‐attempt CTO‐PCI. Methods: Patients who underwent attempted CTO‐PCI between January 2017 and December 2019 were prospectively enrolled. We analyzed the procedural results and 24‐month major adverse cardiac events (MACE) between patients who underwent prior‐failed‐attempt and initial‐attempt CTO‐PCI. MACE was defined as a composite of cardiac death, target vessel‐related myocardial infarction, and ischemia‐driven target vessel revascularization (TVR) during follow‐up. Results: In total, 484 patients who underwent CTO‐PCI (prior‐failed‐attempt, n = 49; initial‐attempt, n = 435) were enrolled during the study period. After propensity score matching (1:3), 147 patients were included in the initial‐attempt group. The proportion of the Japanese‐CTO (J‐CTO) score ≥2 was higher in the patients who underwent prior failed attempt than in those who underwent initial attempt (77.5% vs. 38.8%, p < 0.001). The retrograde approach was more often adopted in the prior‐failed‐attempt group than in the initial‐attempt group (32.7% vs. 3.4%, [P< 0.001). Successful CTO revascularization rates were significantly lower in the prior‐failed attempt‐group than in the initial attempt group (53.1% vs. 83.3%, P < 0.001). The multivariate analysis revealed that J‐CTO score ≥2 [odds ratio (OR), 0.359; 95% confidence interval (CI), 0.159–0.812; P = 0.014], intravascular ultrasound procedure (OR, 4.640; 95% CI, 1.380–15.603; P = 0.013), and prior failed attempt (OR, 0.285; 95% CI, 0.125–0.648; P = 0.003) were the independent predictors for successful CTO revascularization. There were no significant differences in major procedural complications (2.0% vs. 0.7%, p = 0.438) and MACE rates (4.1% vs. 8.8%, p = 0.438) between the groups, mainly due to the TVR rate (4.1% vs. 8.2%, P = 0.522). Conclusions: Compared with initial‐attempt CTO‐PCI, prior‐failed‐attempt CTO‐PCI deserves more attention, since it is associated with a lower successful CTO revascularization rate. Prior failed attempt, J‐CTO score ≥2, and IVUS procedure are the determining factors for predicting successful CTO revascularization. There are no significantly different unfavorable outcomes between patients who undergo prior‐failed‐attempt and initial‐attempt CTO‐PCI. [ABSTRACT FROM AUTHOR]

Recent studies of the northeastern part of the Tibetan Plateau have called attention to two emerging views of how the Tibetan Plateau has grown. First, deformation in northern Tibet began essentially at the time of collision with India, not 10-20 Myr later as might be expected if the locus of activity migrated northward as India penetrated the rest of Eurasia. Thus, the north-south dimensions of the Tibetan Plateau were set mainly by differences in lithospheric strength, with strong lithosphere beneath India and the Tarim and Qaidam basins steadily encroaching on one another as the region between them, the present-day Tibetan Plateau, deformed, and its north-south dimension became narrower. Second, abundant evidence calls for acceleration of deformation, including the formation of new faults, in northeastern Tibet since ~15 Ma and a less precisely dated change in orientation of crustal shortening since ~20 Ma. This reorientation of crustal shortening and roughly concurrent outward growth of high terrain, which swings from NNE-SSW in northern Tibet to more NE-SW and even ENE-WSW in the easternmost part of northeastern Tibet, are likely to be, in part, a consequence of crustal thickening within the high Tibetan Plateau reaching a limit, and the locus of continued shortening then migrating to the northeastern and eastern flanks. These changes in rates and orientation also could result from removal of some or all mantle lithosphere and increased gravitational potential energy per unit area and from a weakening of crustal material so that it could flow in response to pressure gradients set by evolving differences in elevation. Key Points The north-south limits of Tibet were set by lateral variations in strength Roughly 15 million years ago, deformation of NE Tibet accelerated Since 20-15 million years ago, the orientation of shortening rotated eastward ©2013. American Geophysical Union. All Rights Reserved.

Silicon carbide-reinforced aluminum matrix composites (SiCp/Al) have excellent physical properties, but the presence of SiC particles in the reinforcing phase causes severe tool wear and more serious surface defects during cutting, which seriously hinders the machining efficiency of SiCp/Al composites. To improve the surface quality of SiCp/Al composites and improve the tool wear problem, it were carried out that simulation and experimental verification of the milling tool parameters of SiCp/Al composites and experimental study of CMQL with the selected tool parameters. The results show that the cutting tool with rake angle of 4° and relief angle of 10° can achieve efficient cutting of SiCp/Al composites. The CMQL condition can effectively reduce the surface roughness, improve the surface microstructure, reduce tool wear and increase tool life; The increase of cutting speed can reduce the machined surface roughness, while the increase of feed and cutting depth will lead to the increase of surface roughness. [ABSTRACT FROM AUTHOR]