4,219 research outputs found
Some inequalities on totally real submanifolds in locally conformal Kaehler space forms
In this article, we establish sharp relations between the sectional curvature and the shape operator and also between the k-Ricci curvature and the shape operator for a totally real submanifold in a locally conformal Kaehler space form of constant holomorphic sectional curvature with arbitrary codimension.Korea Research Foundation Gran
Outcomes of endovascular treatment for aortic pseudoaneurysm in Behcet's disease
ObjectiveTo evaluate the effectiveness of endovascular stent grafting for surgical management of aortic pseudoaneurysm in patients with Behcet's disease (BD).MethodsWe present a single-institution retrospective cohort of patients with aortic pseudoaneurysm and BD treated with aortic stent grafting. Computed tomography imaging was obtained preoperatively in all patients and once within 2 weeks postoperatively, and then annually. Clinical follow-up and erythrocyte sedimentation rate were used to follow BD activity. Immunosuppressant therapy was instituted prior to endovascular treatment unless a contraindication existed.ResultsFrom 1998 to 2012, 10 patients (eight male, two female; median age, 39) with BD and aortic pseudoaneurysm were treated with endovascular stent grafting at this institution. Ninety percent of these patients received immunosuppressive therapy before and after surgical treatment. The median follow-up period was 57 months (interquartile range, 43-72). The locations of the 12 pseudoaneurysms treated in this cohort were infrarenal abdominal aorta (seven), descending thoracic aorta (four), and aortic arch (one). Median pseudoaneurysm size was 4.5 cm (interquartile range, 3.4-5.9). At long-term follow-up, complete resolution of the aortic pseudoaneurysm was noted in all patients. No endoleaks occurred. Newly developed pseudoaneurysm at the distal margin of the stent graft was noted in one patient 17 months after the stent graft procedure. One patient required a subsequent stent graft placement for an expanding pseudoaneurysm of the subclavian artery. No patient deaths occurred during the follow-up period.ConclusionsEndovascular treatment of aortic pseudoaneurysm with stent-grafting in patients with BD is safe and effective with long-term durability
Computational Synthesis of Wearable Robot Mechanisms: Application to Hip-Joint Mechanisms
Since wearable linkage mechanisms could control the moment transmission from
actuator(s) to wearers, they can help ensure that even low-cost wearable
systems provide advanced functionality tailored to users' needs. For example,
if a hip mechanism transforms an input torque into a spatially-varying moment,
a wearer can get effective assistance both in the sagittal and frontal planes
during walking, even with an affordable single-actuator system. However, due to
the combinatorial nature of the linkage mechanism design space, the topologies
of such nonlinear-moment-generating mechanisms are challenging to determine,
even with significant computational resources and numerical data. Furthermore,
on-premise production development and interactive design are nearly impossible
in conventional synthesis approaches. Here, we propose an innovative autonomous
computational approach for synthesizing such wearable robot mechanisms,
eliminating the need for exhaustive searches or numerous data sets. Our method
transforms the synthesis problem into a gradient-based optimization problem
with sophisticated objective and constraint functions while ensuring the
desired degree of freedom, range of motion, and force transmission
characteristics. To generate arbitrary mechanism topologies and dimensions, we
employed a unified ground model. By applying the proposed method for the design
of hip joint mechanisms, the topologies and dimensions of non-series-type hip
joint mechanisms were obtained. Biomechanical simulations validated its
multi-moment assistance capability, and its wearability was verified via
prototype fabrication. The proposed design strategy can open a new way to
design various wearable robot mechanisms, such as shoulders, knees, and ankles.Comment: 28 pages, 7 figures, Supplementary Material
B.-Y. Chen's inequality for submanifolds of generalized space forms
In this article, we investigate sharp inequalities involving δ-invariants for submanifolds in both generalized complex space forms and generalized Sasakian space forms, with arbitrary codimension.Ministerio de Educación y CienciaPlan Andaluz de Investigación (Junta de Andalucía
- …