1,869 research outputs found
Thymectomy with angioplasty through a thoracoscopic subxiphoid approach with double elevation of the sternum in Masaoka stage III thymoma
No full textSubxiphoid thymectomy with double elevation of the sternum is a novel minimally invasive method that might provide a good surgical view and space for operating.1,2 Here we report the use of this approach to manage a Masaoka stage III thymoma with invasion to the edge of the innominate vein, which proved safe and feasibl
A New Hybrid Optimization Algorithm for the Estimation of Archie Parameters
No full textArchie formula, which contains three fundamental parameters (a, m, n), is the basic equation to compute the water saturation in a clean or shaly formation. These parameters are known as Archie parameters. To identify accurately the water saturation for a given reservoir condition, it depends critically on the accurate estimates of the values of Archie parameters (a, m, n). These parameters are interdependent and hence it is difficult to identify them accurately. So we present a new hybrid global optimization technique, where a gradient-based method with BFGS update is combined with an intelligent algorithm called Artificial Bee Colony. This new hybrid global optimization technique has both the fast convergence of gradient descent algorithm and the global convergence of swarm algorithm. It is used to identify Archie parameters in carbonate reservoirs. The results obtained are highly satisfactory. To further test the effectiveness of the new hybrid global optimization method, it is applied to ten non-convex benchmark problems. The outcomes are encouraging
Bio-inspired nanostructures for enhanced light management
No full textThe biological surface has developed functional structures during long-term evolution, which inspires the development of biomimic materials for optical and optoelectronic applications. For example, the micropapillae and nanofolding structures of rose petals could enhance light absorption and color saturation. Here, the authors report a successful replication of rose hierarchical surface structures by simple and cost-effective processes. A variety of rose structured surfaces were investigated, which confirmed the diversity of functional surface architecture. The polydimethylsiloxane (PDMS) negative replica was formed by casting PDMS solution on top of a rose petal followed by a temperature-assisted curing process. The hierarchical structure was further transferred into photoresist films by ultraviolet nanoimprint using the PDMS replica as molds. The imprinted photoresist films demonstrated uniform replications of rose microconvex cells with nanofolding details in the scale of a square centimeter. Super-hydrophobicity was demonstrated on both PDMS negative replica and photoresist positive replica. The incorporation of photoresist replica on the surface of photodetectors improved the responsivity by 35% to 42% due to enhanced light management effect. This bio-inspired transfer imprint process with PDMS provided a high-fidelity and cost-effective method to reproduce functional structures from biological surfaces. This study also demonstrated the potential of utilizing rose structures in photovoltaic and optoelectronic applications.This work was partially supported by the National Science Foundation (Grant Nos. CBET-1606141 and ECCS-0955027).Erik Jonsson School of Engineering and Computer Scienc
Optimizations in Project Scheduling: A State-of-Art Survey
No full textAbstract Project scheduling is concerned with an optimal allocation of resourcesto activities realized over time. To survive in today’s competitive environment, efficientscheduling for project development becomes more and more important. Theclassical project scheduling is based on the critical path method (CPM) in whichresources required are assumed unlimited. This is however impractical. To overcomeCPM’s drawback, several techniques and optimizations have been proposedin project scheduling literature. In this chapter, we will present a state-of-art surveyon project scheduling from the optimization point of view. In particularly, we willfocus on the advancements of optimization formulations and solutions on projectscheduling in the recent years
An Improved Method for InSAR Atmospheric Phase Correction in Mountainous Areas
No full textTime series interferometric synthetic aperture radar (TS-InSAR) has been a powerful tool for monitoring land surface deformation over the last two decades. Atmospheric effects cause large-scale delays in InSAR observations, which is one of the difficulties facing deformation calculations from differential InSAR and time-series InSAR. Currently, the atmospheric delay is derived mainly from auxiliary data from sources such as the global navigation satellite system (GNSS) and moderate-resolution imaging spectroradiometry (MODIS), but GNSS data are limited by the sparse distribution of observation stations. MODIS data may also not temporally match SAR image acquisition, which leads to low accuracy in atmospheric phase correction. This article presents a decomposition method to remove the atmospheric delay. We consider the atmospheric phase to be caused by the combined changes in spatial position and elevation. Therefore, quadtree segmentation is applied to divide the topographic units, and we improve the drift function of universal kriging by adding an elevation component. We then interpolate the whole atmospheric phase space from reliable sampling points estimated by the coherence coefficient. Using Sentinel-1 data, we test the proposed method in discriminating and monitoring a mining subsidence area in Shanxi Province and compare the results with the results from interferometric point target analysis and the network-based variance-covariance estimation method. The results demonstrate that the proposed method is superior to existing methods for the detection of deformation inverted from TS-InSAR
Stabilization of switched linear systems with time-delay
No full textIn this paper, we discuss a class of switched integro-differential control system with time delayin detection of switching signal, sufficient conditions are given to guarantee the system being asymptotically stable or exponentially stable
sj-rar-3-tej-10.1177_20417314221132093 – Supplemental material for A new cell-free therapeutic strategy for liver regeneration: Human placental mesenchymal stem cell-derived extracellular vesicles
No full textSupplemental material, sj-rar-3-tej-10.1177_20417314221132093 for A new cell-free therapeutic strategy for liver regeneration: Human placental mesenchymal stem cell-derived extracellular vesicles by Ting Li, Yu Fu, Zeyi Guo, Honglei Zhu, Hangyu Liao, Xiaoge Niu, Lin Zhou, Shunjun Fu, Yang Li, Shao Li, Lujia Wang, Yizhou Zheng, Lei Feng, Yi Gao and Guolin He in Journal of Tissue Engineering</p
Robust Optimal Control of Continuous Linear Quadratic System Subject to Disturbances
No full textIn this chapter, the robust optimal control of linear quadratic system is considered. This problem is first formulated as a minimax optimal control problem. We prove that it admits a solution. Based on this result, we show that this infinite-dimensional minimax optimal control problem can be approximated by a sequence of finite-dimensional minimax optimal parameter selection problems. Furthermore, these finite-dimensional minimax optimal parameter selection problems can be transformed into semi-definite programming problems or standard minimization problems. A numerical example is presented to illustrate the developed method
A novel drainage strategy using chest tube plus pleural catheter in uniportal upper lobectomy: A randomized controlled trial
No full textBACKGROUND: In this study we explored whether one pleural catheter plus single chest tube drainage could achieve a noninferior drainage effect when compared with the traditional two chest tubes in uniportal video‐assisted thoracoscopic surgery (VATS) for an upper pulmonary lobectomy. METHODS: Patients that underwent an upper pulmonary lobectomy from January to November 2020 were enrolled in this single‐center, randomized, open‐label, noninferiority trial. Prior to closure, patients were randomized to an intervention group who received an improved drainage strategy involving one pleural catheter with one chest tube (24 Fr), while traditional double chest tube drainage was applied for the control group. RESULTS: A total of 390 patients entered the study, although 190 were excluded for changing nonuniportal surgical approaches or opting for nonlobectomy resections. Finally, 200 patients were randomized (100 in the intervention group and 100 in the control group). The baseline demographic and clinical characteristics were comparable between the groups. The incidence of pneumothorax in the intervention and control groups was similar on postoperative Day 1 (noninferiority, 10% vs. 13%, p = 0.658). In addition, there were no significant differences in secondary outcomes such as incidence of pneumothorax by Day 30, postoperative chest tube/pleural catheter removal time, amount of drainage on Day 1, total amount of drainage after operation, or postoperative hospitalization. A significantly lower pain score was observed in the intervention group (3.33 ± 0.68 vs. 3.68 ± 0.94, p = 0.003). CONCLUSIONS: The new strategy is noninferior to double chest tube drainage after an upper pulmonary lobectomy offers superior pain control, and is recommended for an upper lobectomy by uniportal VATS
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