4,135 research outputs found

    Channel Optimized Visual Imagery based Robotic Arm Control under the Online Environment

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    An electroencephalogram is an effective approach that provides a bidirectional pathway between the user and computer in a non-invasive way. In this study, we adopted the visual imagery data for controlling the BCI-based robotic arm. Visual imagery increases the power of the alpha frequency range of the visual cortex over time as the user performs the task. We proposed a deep learning architecture to decode the visual imagery data using only two channels and also we investigated the combination of two EEG channels that has significant classification performance. When using the proposed method, the highest classification performance using two channels in the offline experiment was 0.661. Also, the highest success rate in the online experiment using two channels (AF3-Oz) was 0.78. Our results provide the possibility of controlling the BCI-based robotic arm using visual imagery data.Comment: 4 pages, 2 figures, 3 table

    An Active and Soft Hydrogel Actuator to Stimulate Live Cell Clusters by Self-folding

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    The hydrogels are widely used in various applications, and their successful uses depend on controlling the mechanical properties. In this study, we present an advanced strategy to develop hydrogel actuator designed to stimulate live cell clusters by self-folding. The hydrogel actuator consisting of two layers with different expansion ratios were fabricated to have various curvatures in self-folding. The expansion ratio of the hydrogel tuned with the molecular weight and concentration of gel-forming polymers, and temperature-sensitive molecules in a controlled manner. As a result, the hydrogel actuator could stimulate live cell clusters by compression and tension repeatedly, in response to temperature. The cell clusters were compressed in the 0.7-fold decreases of the radius of curvature with 1.0 mm in room temperature, as compared to that of 1.4 mm in 37 degrees C. Interestingly, the vascular endothelial growth factor (VEGF) and insulin-like growth factor-binding protein-2 (IGFBP-2) in MCF-7 tumor cells exposed by mechanical stimulation was expressed more than in those without stimulation. Overall, this new strategy to prepare the active and soft hydrogel actuator would be actively used in tissue engineering, drug delivery, and micro-scale actuators

    The Distribution Strategy Of A Representative Fair Trade Organization In Korea: The Case Of Beautiful Coffee

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    This case study analyzes the distribution strategy of Beautiful Coffee, a leading fair trade organization in Korea. Because of their focus on matters of public interest, fair trade organizations often face financial difficulties, and such difficulties can limit their growth and force them to pursue differentiated distribution strategies. The results indicate that Beautiful Coffee can serve as a good role model for fair trade organizations and have important practical implications for firms pursuing sustainable growth as a social enterprise

    Performance Improvement of a High Side Scroll Compressor by Thrust Surface Oil Groove

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    Performance analysis has been carried out on a high side scroll compressor having a fixed scroll equipped with a circular oil groove on its thrust surface. Oil is supplied to the oil groove through an intermittent opening from a high pressure oil reservoir formed inside the orbiting scroll hub. Oil in the groove is then delivered to both suction and back pressure chambers by pressure differentials and viscous pumping action of the orbiting scroll base plate. Mathematical modeling of this oil groove system has been incorporated into main compressor performance simulation program for optimum oil groove design. Pressure in the oil groove can be controlled by changing the oil passage area and oil groove configuration. With an enlarged oil passage, pressure in the oil groove increases due to increased flow rate, but pressure increase in the back pressure chamber is not that large, resulting in reduced friction loss at the thrust surface between the two scrolls. On the other hand, by increasing the oil passage area, oil content in the refrigerant flow increases, and the orbiting scroll stability could be negatively affected by oil groove pressure increase. Considering all these factors, EER could be improved by about 3.6% at ARI condition by optimum oil groove design

    A lab-on-a-disc platform enables serial monitoring of individual CTCs associated with tumor progression during EGFR-targeted therapy for patients with NSCLC

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    Rationale: Unlike traditional biopsy, liquid biopsy, which is a largely non-invasive diagnostic and monitoring tool, can be performed more frequently to better track tumors and mutations over time and to validate the efficiency of a cancer treatment. Circulating tumor cells (CTCs) are considered promising liquid biopsy biomarkers; however, their use in clinical settings is limited by high costs and a low throughput of standard platforms for CTC enumeration and analysis. In this study, we used a label-free, high-throughput method for CTC isolation directly from whole blood of patients using a standalone, clinical setting-friendly platform. Methods: A CTC-based liquid biopsy approach was used to examine the efficacy of therapy and emergent drug resistance via longitudinal monitoring of CTC counts, DNA mutations, and single-cell-level gene expression in a prospective cohort of 40 patients with epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer. Results: The change ratio of the CTC counts was associated with tumor response, detected by CT scan, while the baseline CTC counts did not show association with progression-free survival or overall survival. We achieved a 100% concordance rate for the detection of EGFR mutation, including emergence of T790M, between tumor tissue and CTCs. More importantly, our data revealed the importance of the analysis of the epithelial/mesenchymal signature of individual pretreatment CTCs to predict drug responsiveness in patients. Conclusion: The fluid-assisted separation technology disc platform enables serial monitoring of CTC counts, DNA mutations, as well as unbiased molecular characterization of individual CTCs associated with tumor progression during targeted therapy
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