25,570 research outputs found
sj-docx-1-jdr-10.1177_00220345221106676 – Supplemental material for Deep Learning–Based Prediction of the 3D Postorthodontic Facial Changes
No full textSupplemental material, sj-docx-1-jdr-10.1177_00220345221106676 for Deep Learning–Based Prediction of the 3D Postorthodontic Facial Changes by Y.S. Park, J.H. Choi, Y. Kim, S.H. Choi, J.H. Lee, K.H. Kim and C.J. Chung in Journal of Dental Research</p
Author Correction: Evaluation of skin cancer resection guide using hyper‑realistic in‑vitro phantom fabricated by 3D printing
No full textThe original version of this Article contained an error in the spelling of the author Taehun Kim which was incorrectly given as Teahun Kim. The original Article has been corrected
Effect of PEO grafts on the surface properties of PEO-grafted PU/PS IPNs : AFM study
No full textThe change of the interfacial phenomena of muticomponent polymeric systems based on self-reorganization is very important for many applications of them. Specially, when they are used for biomedical application, the change of surface properties in water is a key factor because they are mostly used in the aqueous environment of the human body. An interpenetrating polymer network (IPN) is a mixture of network polymers. The morphology of an IPN can be controlled to obtain materials with nanoscale domains, and the morphology once formed is permanent due to the presence of the physical interlocking between the networks. In this study, surface compositional mapping was attempted with atomic force microscopy (AFM) images of poly(ethylene oxide)-grafted polyurethane/polystyrene IPNs (PEO-grafted PU/PS IPNs) to investigate the structural change under water, and the effect of hydrophilic PEO pendant chains on the change of local elasticity and surface energy of the IPN under water was studied by using the "force-distance (FID) analysis" of AFM. The compositional mapping in water showed that the area fraction of the hydrophilic PU-rich phase was increased by PEO grafting, but the structural reorganization did not occur. From the result of FID analysis in water, the mobile and flexible pendant PEO chains increased the surface elasticity and softness of PU/PS IPNs. The crystallinity also affected the surface hardness of the dried PEO-grafted PU, but it did not when the samples were swollen in water
Effect of synthesis temperature of PEO-grafted PU/PS IPNs on surface morphology and in vitro blood compatibility
No full textWhen hydrophilic/hydrophobic polymers have a microdomain structure, platelet adhesion and activation are effectively suppressed by prohibition of the excessive assembly of glycoproteins and adenosine triphosphate (ATP) consumption of the platelets on the surface. In this study, poly(ethylene oxide)-grafted hydrophilic polyurethane (PU)/hydrophobic polystyrene (PS) interpenetrating polymer networks (IPNs) were synthesized by varying the synthesis temperature to control the phase separation and the microdomain surface structure, and the effect of the degree of phase separation on the in vitro blood compatibility. The size of the dispersed PS-rich domains in the PU-rich matrix decreased, and the hydrophilicity also decreased as the synthesis temperature of the PS network during the IPN synthesis was decreased, as the phase separation was suppressed during the synthesis. The amount of the adsorbed bovine plasma fibrinogens (BPF) on the PEO-grafted PU/PS IPNs decreased as the synthesis temperature was decreased, and the in vitro adhesion of the platelets was also suppressed on the PEO-grafted PU/PS IPNs prepared at lower temperature. The microdomain structure on the surface affected the adhesion and the activation of the adhered platelets, and the suppression of the phase separation resulted in the decrease of the domain size, which also enhanced the blood compatibility of the PEO-grafted PU/PS IPNs
Controlling the morphology of polyurethane/polystyrene interpenetrating polymer networks for enhanced blood compatibility
No full textPolyurethane (PU)/polystyrene (PS) IPNs were simultaneously synthesized at 80degreesC, controlling the reaction kinetics to change the morphology. Polymerization kinetics of styrene was controlled by the content of initiator, and that of polyurethane by the catalyst concentration. The effect of the initiator and the catalyst on the polymerization rate was analyzed by NMR spectroscopy and FTIR. Gelation time was also measured by using the advanced rheometric expansion system (ARES). Samples with sea-and-island morphology were obtained, when the polymerization rate of PS was relatively slow, and the phase separation time was long. When the polymerization rate of PS was relatively fast, and the phase separation time was short, cocontinuous morphology was obtained. The degree of phase separation and surface roughness decreased, as the rate of PU network formation was increased, and the phase-continuity was increased. The in vitro blood-compatibility tests showed that the surface roughness was an important factor on the adsorption of fibrinogens and platelets. A large amount of fibrinogens and platelets were adsorbed on the relatively rough surface of samples showing sea-island morphology. (C) 2002 John Wiley Sons, Inc
PEO-grafting on PU/PS IPNs for enhanced blood compatibility-effect of pendant length and grafting density
No full textPolyurethane (PU) homopolymers and PU/polystyrene (PS) interpenetrating polymer networks (IPNs) were successfully synthesized changing the length of the pendant poly(ethylene oxide) (PEO) chains and the grafting density of PEO chains. All the PU/PS IPNs had the microphase-separated structures in which the PS-rich phase domains were dispersed in the matrix of the PU-rich phase. The domain size decreased a little, as the degree of grafting with PEO chains was increased. The water swelling ratio increased, and the interfacial energy decreased, as the length of the pendant PEO chains, and the grafting density of PEO chains of the PEO-grafted PU/PS IPNs were increased, since the mobile hydrophilic pendant PEO chains effectively induced and absorbed the water, when they were contacted with water. The hydrophilic and highly concentrated pendant PEO chains could easily prohibit the adhesion of the fibrinogens and the platelets on the surface, and the blood compatibility of IPNs was enhanced by increasing of grafting with PEO chains. The adsorption of the fibrinogens and the platelets was suppressed, as the length of pendant PEO chains, and the grafting density were increased. (C) 2002 Elsevier Science Ltd. All rights reserved
Analysis of reaction injection molding process of polyurethane-unsaturated polyester blends, computer simulation
No full textPrevalence investigation of swine pathogens in the wild rodents and cats
No full textKim, Y.H.; Seo, T.W.; Yi, J.Y.; Hahn, T.W.; Kim, H.C.; Han, J.H.; Yoon, B.I.. (2008). Prevalence investigation of swine pathogens in the wild rodents and cats. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/155086
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