Orthopedic Surgery Planning Based on the Integration of Reverse Engineering and Rapid Prototyping

This paper describes orthopedic surgical planning based on the integration of RE and RP. Using symmetrical characteristics of the human body, CAD data of the original bone without damages for the injured extent are generated from a mirror transformation of undamaged bone data for the uninjured extent. The physical model before the injury is manufactured from RP apparatus. Surgical planning, such as the selection of the proper implant, pre-forming of the implant, decision of fixation positions and incision sizes, etc., is determined by a physical simulation using the physical model. In order to examine the applicability and efficiency of surgical planning technology for orthopedics, various case studies, such as a proximal tibia plateau fracture, a distal tibia comminuted fracture and an iliac wing fracture of pelvis, are carried out. As a result of the examination, it has been shown that the orthopedic surgical planning based on the integration of RE and RP is an efficient surgical tool.Mechanical Engineerin

Double activation of oxygen intermediates of oxygen reduction reaction by dual polymer/oxide electrocatalysts

Department of Energy Engineering (Energy Engineering)Oxygen reduction reaction (ORR) is one of the classical topics in electrochemistry which has been investigated for several decades. ORR, a notoriously sluggish cathodic process, requires an electrocatalyst to improve its kinetics. Platinum is well-known as the best catalyst for ORR. However, due to its high cost, many kinds of catalyst such as non-precious-metal-based catalysts (metal oxide, metal alloy and M-N-C) and metal-free catalysts (nitrogen doped carbon) have been studied as replacements for platinum. These studies on catalyst development commonly focus on significant generation of active sites. In this dissertation, dual polymer/oxide electrocatalytic system is presented, which further improves catalytic activity by adding the polymers that interact with the oxygen, not active site of oxides. The additional components act as co-catalysts by simultaneously participating in ORR with the original catalyst. The double activation of oxygen intermediates in the dual electrocatalytic system reduces adsorption energies of intermediates compared to a single catalytic system. Dual electrocatalysis achieved by simply mixing metal oxide particles (original catalyst) with polymers (additional catalyst) is one of the most efficient and easiest ways to improve the catalytic activity of cost-efficient catalysts to match the level of precious metal catalysts. Firstly, perovskite oxides were investigated as a catalyst for ORR. Perovskite is a good model for the basic investigation of electrocatalysis because their physical properties, especially electrical conductivities, can be dynamically controlled with their composition and stoichiometry. Controlling conductive environment surrounding active sites, achieved by more conductive catalysts (providing internal electric pathways) or higher carbon content (providing external electric pathways), contributes to presenting the conductivity-dependent trend of the number of electron transfer in ORR. Then, the perovskite catalysts were studied in presence of polypyrrole (pPy), which is the first additional catalyst considered for ORR. Nitrogen-containing electrocatalysts such as metal-nitrogen-carbon (M-N-C) composites and nitrogen-doped carbons are known to exhibit high activities for ORR. Even if the mechanism by which nitrogen improves the activities is not completely understood, strong electronic interaction between nitrogen and active sites has been found in these composites. In this work, I demonstrate a case in which nitrogen improves electroactivity, but in the absence of strong interaction with other components. The overpotentials of ORR and oxygen evolution reaction (OER) on perovskite oxide catalysts were significantly reduced by simply mixing the catalyst particles with polypyrrole/carbon composites (pPy/C). Any strong interactions between pPy (a nitrogen-containing compound) and active sites of the catalysts were not confirmed, but interaction between secondary amine(N-H) of pPy and oxygen was observed. To activate oxygen and other intermediates, a series of the secondary amine conjugated polymers (HN-CPs) was tested with three different cobalt-based electrocatalysts (CoO, Co3O4, and LiCoO2). In this work, the synergistic electrocatalysis of oxygen reduction reaction (ORR) was successfully demonstrated by showcasing the significantly improved kinetics of ORR. The electron donation number of the HN-CPs to diatomic oxygen (?? in O2??-) described the order of activity improvement by polypyrrole (pPy) > polyaniline (pAni) > polyindole (pInd). The maximum overpotential gain at ~150 mV was achieved by using pPy, characterized by the highest ??. In the mechanism, the activated diatomic oxygen species (O2??-) was transferred to the active site of electrocatalysts, while maintaining interaction with NH-CPs. As ORR proceeded along the mechanistic pathway following *OO ??? *OOH ??? *O ??? *OH ??? *OO (the surface intermediates on catalyst), the proton of the HN-CP was transferred to the single oxygen surface species (*O). The kinetic gains were obtained in the surface single oxygen formation step (*OOH to *O) at the equilibrium potential and the proton transfer step (*O to *OH) at a biased potential by the dual catalysis, when compared with the conventional electrocatalysis in the absence of OA (RDS = the surface peroxide formation step of *OO to *OOH).clos

RemoteNet: Remote Sensing Image Segmentation Network based on Global-Local Information

Remotely captured images possess an immense scale and object appearance variability due to the complex scene. It becomes challenging to capture the underlying attributes in the global and local context for their segmentation. Existing networks struggle to capture the inherent features due to the cluttered background. To address these issues, we propose a remote sensing image segmentation network, RemoteNet, for semantic segmentation of remote sensing images. We capture the global and local features by leveraging the benefits of the transformer and convolution mechanisms. RemoteNet is an encoder-decoder design that uses multi-scale features. We construct an attention map module to generate channel-wise attention scores for fusing these features. We construct a global-local transformer block (GLTB) in the decoder network to support learning robust representations during a decoding phase. Further, we designed a feature refinement module to refine the fused output of the shallow stage encoder feature and the deepest GLTB feature of the decoder. Experimental findings on the two public datasets show the effectiveness of the proposed RemoteNet

Organizing Pneumonia by Paragonimiasis and Coexistent Aspergilloma Manifested as a Pulmonary Irregular Nodule

Organizing pneumonia by paragonimiasis and coexistent aspergilloma as a pulmonary nodule is a rare case of lung disease. Its radiographic or CT feature has not been described before in the radiologic literature. We present organizing pneumonia by paragonimiasis and coexistent aspergilloma manifested as a pulmonary irregular nodule on CT

Rewarded meta-pruning: Meta Learning with Rewards for Channel Pruning

Convolutional Neural Networks (CNNs) have a large number of parameters and take significantly large hardware resources to compute, so edge devices struggle to run high-level networks. This paper proposes a novel method to reduce the parameters and FLOPs for computational efficiency in deep learning models. We introduce accuracy and efficiency coefficients to control the trade-off between the accuracy of the network and its computing efficiency. The proposed Rewarded meta-pruning algorithm trains a network to generate weights for a pruned model chosen based on the approximate parameters of the final model by controlling the interactions using a reward function. The reward function allows more control over the metrics of the final pruned model. Extensive experiments demonstrate superior performances of the proposed method over the state-of-the-art methods in pruning ResNet-50, MobileNetV1, and MobileNetV2 networks

Estimation of Appropriate Process Parameters for a Plasma Electron Beam Re-Melting Process Using Finite Element Analysis

Metal additive manufacturing using electron beam melting (EBM) process applies electron beam for heating, sintering, and melting of powders to fabricate a three-dimensional component. The component may contain residual porosity internally and may be subjected to poor surface finish externally. To improve the quality of the surface finish and densification, re-melting is conducted. The purpose of this paper was to estimate the appropriate process conditions for a plasma electron beam remelting process using heat transfer finite element analyses (FEAs). The impact of the travel speed of table and thickness of the deposited part on temperature distributions were examined. The size of molten pool was estimated from the results of the thermal FEA. From the estimated size of molten pool, the travel speed of table and the hatch spacing between remelting tracks are discussed and selected as the appropriate process conditions for electron beam re-melting process from the perspective of minimum overlapping region of the molten pool

Comparison of Ulnar Collateral Ligament Reconstruction Techniques in the Elbow of Sports Players

Ulnar collateral ligament injuries have been increasingly common in overhead throwing athletes. Ulnar collateral ligament reconstruction is the current gold standard for managing ulnar collateral ligament insufficiency, and numerous reconstruction techniques have been described. Although good clinical outcomes have been reported regarding return to sports, there are still several technical issues including exposure, graft selection and fixation, and ulnar nerve management. This review article summarizes a variety of surgical techniques of ulnar collateral ligament reconstructions and compares clinical outcomes and biomechanics