The Experts below are selected from a list of 133590 Experts worldwide ranked by ideXlab platform
Richard Slaughter - One of the best experts on this subject based on the ideXlab platform.
-
cryolife o brien stentless valve 10 year results of 402 implants
The Annals of Thoracic Surgery, 2005Co-Authors: Mark F Obrien, Michael A H Gardner, Bruce Garlick, Homayoun Jalali, Julie A Gordon, Wendy E Strugnell, Sarah L. Whitehouse, Richard SlaughterAbstract:Background This truly stentless porcine valve is composite, without Dacron, and implanted supra-annularly. Ten-year analysis with magnetic resonance imaging is presented. Methods From 1992 to 2002, 402 patients (mean 73.5 years) had aortic valve replacement. Associated procedures were required in 252 patients (63%). Serial echoes provided 1340 studies. Clinical follow-up was 100%. Magnetic resonance imaging focused on aortic annulus extensibility. Results The 30-day mortality was 0.99% (4 deaths). Morbidity comprised thromboembolism (40 patients including 18 patients with permanent strokes); endocarditis (9 patients); and reoperation (9 patients [periprosthetic leak, 2; endocarditis, 5; technical needle damage, 1; and Structural degeneration, 1]). Of 402 valves more than 10 years, five valves were explanted, one only for Structural Failure. Except for endocarditis (2 patients), no late deaths (69 patients, 1.5 months to 5.7 years) were valve related. Echocardiography demonstrated low gradients with good orifice areas, excellent ventricular regression ( p = 0.0001 preoperative and postoperative comparisons) and late incompetence (mild in 45 patients and moderate in 9 patients). No living patient has severe incompetence. Magnetic resonance imaging demonstrated the annulus ‘expanding and relaxing' throughout the cardiac cycle, the mean increase in cross-sectional area being 37%, resembling normal aortic root dynamics. Conclusions Elderly patients received this hemodynamically acceptable valve with its simple, supra-annular implantation and satisfactory mid-term morbid-free lifestyle to 10 years maximum follow-up. With only one Structural Failure, restoration of valve annular extensibility may have a favorable influence on long-term durability.
-
cryolife o brien stentless valve 10 year results of 402 implants
Faculty of Built Environment and Engineering, 2005Co-Authors: Mark F Obrien, Michael A H Gardner, Bruce Garlick, Homayoun Jalali, Julie A Gordon, Wendy E Strugnell, Sarah L. Whitehouse, Richard SlaughterAbstract:Background This truly stentless porcine valve is composite, without Dacron and implanted supra-annularly. Ten year analysis with magnetic resonance imaging is presented. Methods From 1992 to 2002, 402 patients (mean 73.5 yrs) had aortic valve replacement. Associated procedures were required in 252 patients (63%). Serial echoes provided 1340 studies. Clinical follow-up was 100%. Magnetic Resonance Imaging focused on aortic annulus extensibility. Results The 30 day mortality was 0.99% (4 deaths). Morbidity comprised (a) thromboembolism (40 patients including 18 patients with permanent strokes); (b) endocarditis (nine patients); (c) re-operation (nine patients) - peri-prosthetic leak (2), endocarditis (5), technical needle damage (1) and Structural degeneration (1). Of 402 valves over 10 years, five valves were explanted, one only for Structural Failure. Except for endocarditis (2), no late deaths (69 pts, 1.5 months – 5.7 yrs) were valve related. Echocardiography demonstrated low gradients with good orifice areas, excellent ventricular regression (p = 0.0001 pre and post-operative comparisons) and late incompetence - mild (45 pts) and moderate (nine pts). No living patient has severe incompetence. Magnetic Resonance Imaging demonstrated the annulus ‘expanding and relaxing’ throughout the cardiac cycle, the mean increase in cross-sectional area being 37%, resembling normal aortic root dynamics. Conclusion Elderly patients received this hemodynamically acceptable valve with its simple, supra-annular implantation and satisfactory mid-term morbid-free lifestyle to 10 years maximum follow-up. With only one Structural Failure, restoration of valve annular extensibility may have a favourable influence on long-term durability.
Mark F Obrien - One of the best experts on this subject based on the ideXlab platform.
-
cryolife o brien stentless valve 10 year results of 402 implants
The Annals of Thoracic Surgery, 2005Co-Authors: Mark F Obrien, Michael A H Gardner, Bruce Garlick, Homayoun Jalali, Julie A Gordon, Wendy E Strugnell, Sarah L. Whitehouse, Richard SlaughterAbstract:Background This truly stentless porcine valve is composite, without Dacron, and implanted supra-annularly. Ten-year analysis with magnetic resonance imaging is presented. Methods From 1992 to 2002, 402 patients (mean 73.5 years) had aortic valve replacement. Associated procedures were required in 252 patients (63%). Serial echoes provided 1340 studies. Clinical follow-up was 100%. Magnetic resonance imaging focused on aortic annulus extensibility. Results The 30-day mortality was 0.99% (4 deaths). Morbidity comprised thromboembolism (40 patients including 18 patients with permanent strokes); endocarditis (9 patients); and reoperation (9 patients [periprosthetic leak, 2; endocarditis, 5; technical needle damage, 1; and Structural degeneration, 1]). Of 402 valves more than 10 years, five valves were explanted, one only for Structural Failure. Except for endocarditis (2 patients), no late deaths (69 patients, 1.5 months to 5.7 years) were valve related. Echocardiography demonstrated low gradients with good orifice areas, excellent ventricular regression ( p = 0.0001 preoperative and postoperative comparisons) and late incompetence (mild in 45 patients and moderate in 9 patients). No living patient has severe incompetence. Magnetic resonance imaging demonstrated the annulus ‘expanding and relaxing' throughout the cardiac cycle, the mean increase in cross-sectional area being 37%, resembling normal aortic root dynamics. Conclusions Elderly patients received this hemodynamically acceptable valve with its simple, supra-annular implantation and satisfactory mid-term morbid-free lifestyle to 10 years maximum follow-up. With only one Structural Failure, restoration of valve annular extensibility may have a favorable influence on long-term durability.
-
cryolife o brien stentless valve 10 year results of 402 implants
Faculty of Built Environment and Engineering, 2005Co-Authors: Mark F Obrien, Michael A H Gardner, Bruce Garlick, Homayoun Jalali, Julie A Gordon, Wendy E Strugnell, Sarah L. Whitehouse, Richard SlaughterAbstract:Background This truly stentless porcine valve is composite, without Dacron and implanted supra-annularly. Ten year analysis with magnetic resonance imaging is presented. Methods From 1992 to 2002, 402 patients (mean 73.5 yrs) had aortic valve replacement. Associated procedures were required in 252 patients (63%). Serial echoes provided 1340 studies. Clinical follow-up was 100%. Magnetic Resonance Imaging focused on aortic annulus extensibility. Results The 30 day mortality was 0.99% (4 deaths). Morbidity comprised (a) thromboembolism (40 patients including 18 patients with permanent strokes); (b) endocarditis (nine patients); (c) re-operation (nine patients) - peri-prosthetic leak (2), endocarditis (5), technical needle damage (1) and Structural degeneration (1). Of 402 valves over 10 years, five valves were explanted, one only for Structural Failure. Except for endocarditis (2), no late deaths (69 pts, 1.5 months – 5.7 yrs) were valve related. Echocardiography demonstrated low gradients with good orifice areas, excellent ventricular regression (p = 0.0001 pre and post-operative comparisons) and late incompetence - mild (45 pts) and moderate (nine pts). No living patient has severe incompetence. Magnetic Resonance Imaging demonstrated the annulus ‘expanding and relaxing’ throughout the cardiac cycle, the mean increase in cross-sectional area being 37%, resembling normal aortic root dynamics. Conclusion Elderly patients received this hemodynamically acceptable valve with its simple, supra-annular implantation and satisfactory mid-term morbid-free lifestyle to 10 years maximum follow-up. With only one Structural Failure, restoration of valve annular extensibility may have a favourable influence on long-term durability.
Chikatoshi Honda - One of the best experts on this subject based on the ideXlab platform.
-
the western bulge of 162173 ryugu formed as a result of a rotationally driven deformation process
arXiv: Earth and Planetary Astrophysics, 2019Co-Authors: Masatoshi Hirabayashi, Eri Tatsumi, Hideaki Miyamoto, Goro Komatsu, Seiji Sugita, Seiichiro Watanabe, Daniel J Scheeres, O S Barnouin, P Michel, Chikatoshi HondaAbstract:162173 Ryugu, the target of Hayabusa2, has a round shape with an equatorial ridge, which is known as a spinning top-shape. A strong centrifugal force is a likely contributor to Ryugu's top-shaped features. Observations by Optical Navigation Camera onboard Hayabusa2 show a unique longitudinal variation in geomorphology; the western side of this asteroid, later called the western bulge, has a smooth surface and a sharp equatorial ridge, compared to the other side. Here, we propose a Structural deformation process that generated the western bulge. Applying the mission-derived shape model, we employ a finite element model technique to analyze the locations that experience Structural Failure within the present shape. Assuming that materials are uniformly distributed, our model shows the longitudinal variation in Structurally failed regions when the spin period is shorter than ~3.75 h. Ryugu is Structurally intact in the subsurface region of the western bulge while other regions are sensitive to Structural Failure. We infer that this variation is indicative of the deformation process that occurred in the past, and the western bulge is more relaxed Structurally than the other region. Our analysis also shows that this deformation process might occur at a spin period between ~3.5 h and ~3.0 h, providing the cohesive strength ranging between ~4 Pa and ~10 Pa.
-
the western bulge of 162173 ryugu formed as a result of a rotationally driven deformation process
The Astrophysical Journal, 2019Co-Authors: Masatoshi Hirabayashi, Eri Tatsumi, Hideaki Miyamoto, Goro Komatsu, Seiji Sugita, Seiichiro Watanabe, Daniel J Scheeres, O S Barnouin, P Michel, Chikatoshi HondaAbstract:162173 Ryugu, the target of Hayabusa2, has a round shape with an equatorial ridge, which is known as a spinning top shape. A strong centrifugal force is a likely contributor to Ryugu's top-shaped features. Observations by the Optical Navigation Camera on board Hayabusa2 show a unique longitudinal variation in geomorphology; the western side of this asteroid, later called the western bulge, has a smooth surface and a sharp equatorial ridge, compared to the other side. Here, we propose a Structural deformation process that generated the western bulge. Applying the mission-derived shape model, we employ a finite element model technique to analyze the locations that experience Structural Failure within the present shape. Assuming that materials are uniformly distributed, our model shows the longitudinal variation in Structurally failed regions when the spin period is shorter than ~3.75 hr. Ryugu is Structurally intact in the subsurface region of the western bulge while other regions are sensitive to Structural Failure. We infer that this variation is indicative of the deformation process that occurred in the past, and the western bulge is more relaxed Structurally than the other region. Our analysis also shows that this deformation process might occur at a spin period between ~3.5 and ~3.0 hr, providing the cohesive strength ranging between ~4 and ~10 Pa.
Guangchun Zhou - One of the best experts on this subject based on the ideXlab platform.
-
stressing state analysis of an integral abutment curved box girder bridge model
Materials, 2019Co-Authors: J Shen, Guangchun Zhou, Xiaohui Yu, Pengcheng LiAbstract:This paper experimentally investigates the working behavior characteristics of an integral abutment curved box-girder (IACBG) bridge model based on the Structural stressing state theory. First, the stressing state of the bridge model is represented by generalized strain energy density (GSED) values at each load Fj and characterized by the normalized GSED sum Ej,norm. Then, the Mann-Kendall (M-K) criterion is adopted to detect the stressing state mutations of the bridge model from Ej,norm-Fj curve in order to achieve the new definition of Structural Failure load. Correspondingly, the stressing state modes for the bridge model’s sections and internal forces are reached in order to investigate their variation characteristics and the coordinated working behavior around the updated Failure load. The unseen knowledge is revealed by studying working behavior characteristics of the bridge model. Therefore, the analytical results could provide a new Structural analysis method, which updates the definition of the existing Structural Failure load and provides a reference for future design of the bridges.
-
experimental investigation into stressing state characteristics of large curvature continuous steel box girder bridge model
Construction and Building Materials, 2018Co-Authors: Weitao Li, Kaikai Zheng, Kangkang Yang, Guangchun ZhouAbstract:Abstract This paper conducts the experimental investigation into the whole working process of a large-curvature continuous steel box-girder bridge model to reveal its behavior characteristics and unseen Failure mechanism, based on the Structural stressing state theory. Firstly, the Structural stressing state and corresponding characteristic parameters are expressed by the generalized strain energy density (GSED) derived from the experimental strain data. Then, the Mann-Kendall (M-K) criterion is introduced to distinguish the Structural stressing state leaps of the bridge model, leading to the updated definition of the Structural Failure load and the revelation of Structural progressive Failure. Furthermore, this paper proposes stressing state submodes and evaluates their roles in the Structural “Failure”. Finally, the coordinative working performance of the divided sub parts is modeled through the ratios between the GSED sums of individual sub parts and the ensemble.
Christian Gerber - One of the best experts on this subject based on the ideXlab platform.
-
long term outcome after Structural Failure of rotator cuff repairs
Journal of Bone and Joint Surgery American Volume, 2006Co-Authors: Bernhard Jost, Christian W A Pfirrmann, Matthias A Zumstein, Christian GerberAbstract:Background: In a previous study, twenty consecutive patients with a rerupture of the rotator cuff, as documented with magnetic resonance imaging, were found to have significantly less pain and better function and strength, compared with the preoperative state, at 3.2 years postoperatively. It was the purpose of this study to determine the clinical and Structural outcomes of these reruptures in the same twenty patients after a longer period of follow-up. Methods: At a mean of 7.6 years postoperatively, the twenty patients were reexamined clinically and with standard radiographs and magnetic resonance imaging with use of the same clinical, radiographic, and magnetic resonance imaging criteria as were utilized in the review at 3.2 years. The mean age at the time of final follow-up was sixty-six years. Results: Nineteen of the twenty patients continued to be either very satisfied or satisfied with the outcome. The relative Constant score averaged 88% and was not significantly different from the score at 3.2 years, which averaged 83%. The mean scores for pain, function, and strength also had not changed significantly. Overall, the twenty reruptures had not increased in size, and eight of them had healed Structurally at the time of the 7.6-year follow-up. Seven of these eight reruptures had been of the supraspinatus tendon only, and seven had been smaller than 400 mm2 at 3.2 years. Twelve reruptures persisted, and five were larger than the preoperative tear. Fatty infiltration of the infraspinatus muscle progressed significantly (p = 0.015) and the acromiohumeral distance decreased significantly (p = 0.006) between the two follow-up periods. Neither fatty infiltration of the supraspinatus and subscapularis muscles nor glenohumeral osteoarthritis progressed significantly. Conclusions: At an average of 7.6 years, the clinical outcomes after Structural Failure of rotator cuff repairs remained significantly improved over the preoperative state in terms of pain, function, strength, and patient satisfaction. Overall, the reruptures that had been present at 3.2 years did not increase in size. We also found that reruptures of the supraspinatus that had been smaller than 400 mm2 had the potential to heal. Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.
-
clinical outcome after Structural Failure of rotator cuff repairs
Journal of Bone and Joint Surgery American Volume, 2000Co-Authors: Bernhard Jost, Christian W A Pfirrmann, Christian GerberAbstract:Background: The clinical outcome for patients with documented rerupture after open repair of one or more rotator cuff tendons is not well known. The purpose of this study was to evaluate the clinical outcomes of a consecutive series of rotator cuff reruptures after repair and to provide information concerning the advisability of rotator cuff repair in situations in which there may be a high probability of rerupture. Methods: During prospective follow-up after rotator cuff repairs, we detected, with magnetic resonance imaging, Structural Failure of the repair in twenty patients, who had a mean age of fifty-nine years at the time of the rotator cuff repair. All patients were clinically examined for the purpose of this report at a mean of thirty-eight months. Results: The reruptures invariably involved the originally torn tendon but were smaller than the original tear in sixteen of the twenty patients. Fatty degeneration of the supraspinatus and infraspinatus muscles, atrophy of the supraspinatus muscle, and glenohumeral osteoarthritis progressed significantly from the preoperative state (p < 0.05). At the time of the most recent follow-up, the subjective shoulder value averaged 75 percent of the value for a normal shoulder. Eleven patients were very satisfied with the result, six were satisfied, two were disappointed, and one was dissatisfied. The mean relative score according to the system of Constant and Murley had increased from 49 percent of the score for a normal shoulder preoperatively to 83 percent postoperatively (p = 0.0001). Pain had decreased significantly, and the ranges of active, pain-free forward elevation and abduction as well as the abduction strength had improved significantly (p < 0.05). The clinical outcome was significantly correlated with the size of the postoperative tear, the stage of postoperative fatty muscle degeneration of the infraspinatus and subscapularis, the postoperative acromiohumeral distance, and the degree of postoperative glenohumeral osteoarthritis (p < 0.05). Conclusions: This study documents that an attempt at rotator cuff repair significantly decreases pain (p = 0.0026) and significantly improves function (p = 0.0005) and strength (p = 0.0137) even if magnetic resonance imaging documents that the repair has failed. This finding suggests that the potential for rerupture should not be considered a formal contraindication to an attempt at repair if optimal functional recovery is the goal of treatment.
