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Mg-3Al-1Zn magnesium alloy sheets processed by high temperature rolling were annealed at different temperatures ranging from 250°C to 500°C, which resulted in an increase in grain size from 7μm to 16μm but similarly retained weak basal textures. The annealed sheets were used for investigating the influences of grain size on mechanical properties and press formability at room temperature. Increasing the grain size results in a decrease in r-value and an increase in n-value, which are generally favored for the improvement of sheet formability. However, both stretch formability and deep drawability deteriorate with an increase in grain size. The sheet annealed at 250°C exhibits superior deep drawability with a high limited drawing ratio of 1.87. In contrast, the sheet annealed at 500°C fractures at the flange when drawn at a ratio of 1.72. For the former sheet, the restricted tensile twinning activity due to the smaller grain size leads to a delay of texture strengthening for the TD-texture forming at the flange during deformation, which is responsible for the enhanced deep drawability. [ABSTRACT FROM AUTHOR]

Background. The purpose of this study was to review our experience with modified De Vega tricuspid annuloplasty versus ring annuloplasty for treating functional tricuspid regurgitation (TR). Methods. In all, 448 consecutive patients undergoing tricuspid annuloplasty with concomitant procedures between 2000 and 2012 were included. Modified De Vega annuloplasty was performed in 216 patients (group 1) and ring annuloplasty in 232 patients (group 2). Clinical and echocardiographic follow-up results were used to assess TR grade. Recurrent TR was defined as grade 2 or greater at echocardiography. Results. Preoperative clinical and echocardiographic characteristics were comparable in the two groups. Early mortality was similar (group 1, 0.9%, versus group 2,1.3%; p < 0.67). Follow-up was available for 97%; New York Heart Association class and symptoms of right-side heart failure were significantly improved. Survival rates at 1 and 5 years were comparable (97% and 84% for group 1, and 96% and 82% for group 2, respectively). Postoperative echocardiography showed significant improvement in tricuspid valve function, with reduction in TR grade from 3.4 to 0.6, and no differences between groups. However, recurrence-free survival was better for group 2 than for group 1 (78.8% versus 74.5%; p < 0.62). Risk factors for recurrent TR included severity of preoperative TR, atrial fibrillation, and pulmonary hypertension. Conclusions. The modified De Vega tricuspid annuloplasty is acceptable for repair of functional TR and improvements in clinical and echocardiographic status on a long-term basis, although the long-term recurrence-free survival appeared to be lower than that for ring annuloplasty. [ABSTRACT FROM AUTHOR]

Mutual information (MI) has been widely used in multisensor image matching, but it may lead to mismatch among images with messy background. However, additional prior information can be of great help in improving the matching performance. In this paper, a robust Bayesian estimated mutual information, named as BMI, for multisensor image matching is proposed. This method has been implemented by utilizing the gradient prior information, in which the prior is estimated by the kernel density estimate (KDE) method, and the likelihood is modeled according to the distance of orientations. To further improve the robustness, we restrict the matching within the regions where the corresponding pixels of template image are salient enough. Experiments on several groups of multisensor images show that the proposed method outperforms the standard MI in robustness and accuracy and is similar with Pluim's method. However, our computation is far more cost saving. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the feasibility, safety and efficacy of the Spider™ patent foramen ovale (PFO) occluder for the treatment of PFOs in an animal model. Method: The foramen ovale was punctured to establish an animal model of a PFO. Under fluoroscopic guidance, the PFO was occluded with the Spider PFO occluder. The piglets were electively sacrificed at months 1, 2, 3, 6 and 12 after occlusion for macroscopic and microscopic examination. Results: PFOs were successfully created and occluded percutaneously in 20 piglets. All piglets recovered from the procedure in good condition and completed follow-up. Macroscopic examination of all hearts showed complete closure of the PFO. The position of each device was correct. All devices were completely covered and embedded in pale and smooth tissue. There was no evidence of interference with adjacent structures of the heart or valves. The occluder was partially covered by endocardium after 1 month, almost completely covered by fresh endocardium after 3 months, and embedded within thick fibrous tissues and fresh vessels after 6 months. The tissue covering both occluder discs demonstrated some infiltration of inflammatory cells, including patches of lymphocyte aggregation. This inflammatory cell reaction diminished with increasing distance from the device. Furthermore, the number of inflammatory cells decreased gradually during follow-up and eventually, at 6-month follow-up, the inflammatory response was no longer visible. The 12-month histological findings did not differ from the 6-month findings. Conclusion: Transcatheter closure of PFO with the Spider PFO occluder is effective and safe in an animal model. These results support further investigation of this device in animals and, if the results are confirmed, in human clinical trials. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Aims: There existed an ambiguity in the current echo literature about the identification of the pulmonary veins imaged by echocardiography. This study was designed to identify the site and blood flow of individual pulmonary veins by transthoracic echocardiography. [ABSTRACT FROM PUBLISHER]

In order to decrease the power consumption of current piezoelectric stack actuator for incus-body driving type middle ear implant (MEI), a new MEI's piezoelectric actuator with a flextensional amplifier was proposed. To aid the design process of this actuator, a human middleear mechanical model, which incorporated the viscoelastic properties of middle ear soft tissues, was established using finite element method. And the validation of this model was confirmed by comparing the model-predicted results with temporal bone experimental data. Then, based on this model, a coupling mechanical model of the flextensional piezoelectric actuator and the human ear was constructed and used to study the equivalent sound pressure level and power consumption of the actuator. The results show that the hearing compensation performance of the piezoelectric actuator was improved by introducing the flextensional amplifier, and the power consumption of the actuator was reduced significantly. [ABSTRACT FROM AUTHOR]