1,172 research outputs found
Dexamethasone nano-aggregates composed of PEG-PLA-PEG triblock copolymers for anti-proliferation of smooth muscle cells
No full textDexamethasone nano-aggregate was prepared for the treatment of intimal hyperplasia caused by abnormal proliferation of smooth muscle cells. Triblock copolymers composed of poly(ethylene glycol) [PEG] and poly(D,L-lactic acid) [PLA] were synthesized with different chain lengths of PEG. Triblock copolymers in organic phase were mixed with dexamethasone and dexamethasone nano-aggregates was prepared by dispersing the organic phase into water. The average diameter of the nano-aggregates ranged from 200 to 300 nm. Dexamethasone was released out from the nano-aggregates and the release profile was dependent on PEG chain lengths. The dexamethasone nano-aggregates showed superior anti-proliferation effects on smooth muscle cells compared to dexamethasone. Flow cytometry showed that smooth muscle cells treated with dexamethasone nano-aggregates was arrested at a dormant phase in a dose-dependent manner. The dexamethasone nano-aggregates are expected to be a potent candidate for anti-proliferating smooth muscle tissues after a balloon-catheter treatment. (c) 2006 Published by Elsevier B.V.Kangwon National
University
Robust real-time wireless control platform compensating for packet loss
No full textPacket loss compensation techniques are increasingly important to stable remote control over wireless communication in WNCS (Wireless Networked Control Systems). Its time varying channels, limited bandwidth, interference, and poor signal not only leads to packet loss or latency, but also can negatively affect performance and system stability. This paper presents a compensation technique exploiting an EWMA (Exponentially Weighed Moving Average)-based value estimator to clarify the influence of packet loss on the overall WNCS behavior. As an example of actuator to be remotely controlled, a rotary-type inverted pendulum has been considered, and modeled. Performance evaluation results through Matlab/Simulink and Truetime co-simulation confirm the superiority of the proposed value estimation method over previous approaches. © ICROS 2012.
IMAGE SEGMENTATION METHOD USING HIGHER-ORDER CLUSTERING, SYSTEM FOR PROCESSING THE SAME AND RECORDING MEDIUM FOR STORING THE SAME
No full textDisclosed herein is a method of processing images based on image segmentation using higher-order correlation clustering. In an image segmentation method according to an embodiment of the present invention, an input image is segmented into superpixels. A hypergraph is constructed by connecting two or more adjacent superpixels, among the superpixels, to one another. A joint feature map is created by extracting feature vectors from respective edges of the hypergraph, and partitioning the hypergraph based on higher-order correlation clustering in consideration of specific constraints
Targeted Theranostic Strategy for Atherosclerotic Plaques Using Intravascular Multimodal Imaging Techniques
No full textAtherosclerosis, a chronic inflammatory disease, is a leading cause of fatal cardiovascular events including myocardial infarction and stroke, primarily due to plaque rupture. The development of plaques is largely driven by the accumulation of macrophages and lipids within the arterial walls, which are central to the progression of atherosclerotic lesions and have emerged as potential therapeutic targets. However, current therapies cannot accurately target and resolve high-risk inflamed plaques, often leading to off-target damage to healthy vascular cells and increasing complications, such as thrombosis. Additionally, most theranostic strategies, which integrate both diagnostic and therapeutic capabilities, have primarily demonstrated efficacy in murine models, limiting their direct application to human coronary arteries. Recent advancements in targeted drug delivery and photoactivation strategies, combined with customized intravascular structural-molecular imaging, have shown significant promise in overcoming these challenges. Multimodal imaging techniques, such as optical coherence tomography (OCT) and near-infrared fluorescence (NIRF), enable real-time visualization and the precise treatment of plaque inflammation. OCT offers high-resolution imaging of plaque structures, while NIRF detects inflammatory activity, enabling accurate localization of macrophage- and lipid-rich plaques. Following targeted delivery and uptake by plaque macrophages, these theranostic strategies can rapidly resolve plaque inflammation and promote stabilization through orchestrated therapeutic interactions. Accordingly, these clinically relevant theranostic strategies could offer a promising path toward personalized, imaging-guided therapies for human cardiovascular disease, potentially revolutionizing the diagnosis and treatment of atherosclerosis.
Gram-Scale Synthesis of Highly Active and Durable Octahedral PtNi Nanoparticle Catalysts for Proton Exchange Membrane Fuel Cell
No full textProton exchange membrane fuel cells (PEMFC) are regarded as a promising renewable energy source for a future hydrogen energy society. However, highly active and durable catalysts are required for the PEMFCs because of their intrinsic high overpotential at the cathode and operation under the acidic condition for oxygen reduction reaction (ORR). Since the discovery of the exceptionally high surface activity of Pt3Ni(111), the octahedral PtNi nanoparticles have been synthesized and tested. Nonetheless, their milligram-scale synthesis method and poor durability make them unsuitable for the commercialization of PEMFCs. In this study, we focus on gram-scale synthesis of octahedral PtNi nanoparticles with Pt overlayers (PtNi@Pt) supported on the carbon, resulting in enhanced catalytic activity and durability. Such PtNi@Pt catalysts show high mass activity (1.24 A mgPt−1) at 0.9 V (vs RHE) for the ORR, compared to commercial Pt/C (0.22 A mgPt−1). Single-cell performance and electrochemical impedance spectroscopy (EIS) were also tested. The PtNi@Pt catalysts showed enhanced current density of 3.1 A cm−2 at 0.6 V in O2 flow while the commercial Pt/C had the value of 2.5 A cm−2. After 30,000 cycles of the accelerated degradation test (ADT), the PtNi@Pt still showed better performance than the commercial Pt/C in a single-cell system. The Pt layers deposition could enhance the catalytic performance and durability of octahedral PtNi nanoparticles
Thermoplasmonic Optical Fiber for Localized Neural Stimulation
No full textThermoplasmonic effect-based neural stimulation has been suggested as an alternative optical neural stimulation technology without genetic modification. Integration of near-infrared light with plasmonic gold nanoparticles has been demonstrated as a neuromodulation tool on in vitro neuronal network models. In order to further test the validity of the thermoplasmonic neural stimulation across multiple biological models (in vitro, ex vivo, and in vivo) avoiding genetic modification in optical neuromodulation, versatile engineering approaches to apply the thermoplasmonic effect would be required. In this work, we developed a gold nanorod attached optical fiber technology for the localized neural stimulation based on a thermoplasmonic effect. A simple fabrication process was developed for efficient nanoparticle coating on commercial optical fibers. The thermoplasmonic optical fiber proved that it can locally modulate the neural activity in vitro. Lastly, we simulated the spatiotemporal temperature change by the thermoplasmonic optical fiber and analyzed its applicability to in vivo animal models. Copyright © 2020 American Chemical Society.1
Hyaluronic acid modified biodegradable scaffolds for cartilage tissue engineering
No full textHyaluronic acid (hyaluronan, HA) was immobilized onto the surface of macroporous biodegradable poly(D,L-lactic acid-co-glycolic acid) [PLGA] scaffolds to enhance the attachment, proliferation. and differentiation of chondrocyles for cartilage tissue engineering. The PLGA scaffolds were prepared by blending PLGA with varying amounts of amine-terminated PLGA-PEG di-block copolymer. They were fabricated by a gas foaming/salt leaching method. HA was chemically conjugated to the surface-exposed amine groups on the pre-fabricated scaffolds. The amount of surface exposed free amine groups was quantitatively determined by conjugating an amine-reactive fluorescent dye to the PLGA blend films. The extent of HA immobilization was also confirmed by measuring water contact angles. When chondrocytes were seeded within HA modified PLGA scaffolds, enhanced cellular attachment was observed compared to unmodified PLGA scaffolds. Furthermore, glycosaminoglycan and total collagen synthesis increased substantially for HA modified PLGA scaffolds. RT-PCR result and histological examination of the resultant cartilage tissue revealed that HA modified scaffolds excelled in inducing cartilage tissue formation in terms of collagen type 11 expression and tissue morphological characteristics. (C) 2004 Elsevier Ltd. All rights reserved.the Korea
Research Foundation (R11-1997-044-06002-0) and from
the Korea Science and Engineering Foundation (R01-
2003-000-10362-0), Korea
Machine vision for vial-positioning detections towards safe automation of material synthesis
No full textThis repository contains an DenseSSD's datasets that predicts vial-positioning detection using object detection techniques. DenseSSD can play vital roles in addressing these safety issues as well as can alert to user's messenger to notify and fix safety issues as soon as possible
Single Pass Laser Process for Super-Hydrophobic Flexible Surfaces with Micro/Nano Hierarchical Structures
No full textWetting has been studied in various fields: chemical industry, automobile manufacturing, food companies, and even life sciences. In these studies, super-hydrophobic surfaces have been achieved through complex steps and processes. To realize super-hydrophobicity, however, we demonstrated a simple and single pass laser process for the fabrication of micro/nano hierarchical structures on the flexible polytetrafluoroethylene (PTFE, Teflon) surface. The fabricated hierarchical structures helped increase the hydrophobicity by augmenting the surface roughness and promoting air-trapping. In addition, we employed a low-cost and high-throughput replication process producing numerous polydimethylsiloxane (PDMS) replicas from the laser-processed PTFE film. Thanks to the anti-adhesive characteristics of PTFE and the elasticity of PDMS, the structure perfectly transferred to the replica without any mechanical failure. Moreover, our designed mesh patterns offered the possibility of large area applications through varying the process parameters (pitch, beam spot size, laser fluence, and scan speed). Even though mesh patterns had relatively large pitch (190 μm), we were able to achieve high contact angle (>150°). Through pneumatically deformed structure, we clearly showed that the shape of the droplets on our laser-processed super-hydrophobic surface was spherical. Based on these outcomes, we can expect our single laser pulse exposure process can overcome many drawbacks and offer opportunities for advancing applications of the wetting phenomena
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