Selective adhesion of intestinal epithelial cells on patterned films with amine functionalities formed by plasma enhanced chemical vapor deposition

Control of cell adhesion to surfaces is important to develop analytical tools in the areas of biomedical engineering. To control cell adhesiveness of the surface, we constructed a variety of plasma polymerized hexamethyldisiloxane (PPHMDSO) thin films deposited at the plasma power range of 10-100 W by plasma enhanced chemical vapor deposition (PECVD). The PPHMDSO film that was formed at 10 W was revealed to be resistant to cell adhesion. The resistance to cell adhesion is closely related to physicochemical properties of the film. Atomic force microscopic data show an increase in surface roughness from 0.52 nm to 0.74 nm with increasing plasma power. From Fourier transform infrared (FT-IR) absorption spectroscopy data, it was also determined that the methyl (-CH₃) peak intensity increases with increasing plasma power, whereas the hydroxyl (-OH) peak decreases. X-ray photoelectron spectroscopy data reveal an increase in C-O bonding with increasing plasma power. These results suggest that C-O bonding and hydroxyl (-OH) and methyl (-CH₃) functional groups play a critical part in cell adhesion. Furthermore, to enhance a diversity of film surface, we accumulated the patterned plasma polymerized ethylenediamine (PPEDA) thin film on the top of the PPHMDSO thin film. The PPEDA film is established to be strongly cell-adherent. This patterned two-layer film stacking method can be used to form the selectively limited cell-adhesive PPEDA spots over the adhesion-resistant surface.     

A lateral speckle tracking algorithm for ultrasound elastography

Journal of the Korean Physical Society - Speckle tracking is widely used for elastography in ultrasound imaging. Traditional speckle tracking algorithms accurately detect axial motion, but have...     

Particle-hole symmetry and the nu=5/2 quantum Hall state

We discuss the implications of approximate particle-hole symmetry in a half-filled Landau level in which a paired quantum Hall state forms. We note that the Pfaffian state is not particle-hole symmetric. Therefore, in the limit of vanishing Landau-level mixing, in which particle-hole transformation is an exact symmetry, the Pfaffian spontaneously breaks this symmetry. There is a particle-hole conjugate state, which we call the anti-Pfaffian, which is degenerate with the Pfaffian in this limit. We observe that strong Landau-level mixing should favor the Pfaffian, but it is an open problem which state is favored for the moderate Landau-level mixing which is present in experiments. We discuss the bulk and edge physics of the anti-Pfaffian. We analyze a simplified model in which transitions between analogs of the two states can be studied in detail. Finally, we discuss experimental implications.     

A Study on Usefulness Comparison of Multiple-Shot FSE PROPELLER and IDEAL-FSE Techniques for Magnetic Susceptibility Artifact

The aim of this study was to visualize multiple-shot fast spin echo (FSE) images using a periodically rotated overlapping parallel line with enhanced reconstruction (PROPELLER) technique. An iterative decomposition of water and fat with echo asymmetry and a least squares estimation (IDEAL) technique were also performed to reduce the image distortion or susceptibility artifact depending on the difference in magnetic susceptibility to the surrounding tissues caused by metal insertion. The utility of this technique was examined quantitatively. A ferromagnetic image was generated from all the metals, but the IDEAL technique caused less image distortion than the PROPELLER technique. The 3-point IDEAL technique, which used the difference in the signal phase of fat and water, required more time for the examination and image reconstruction than the PROPELLER technique, which was based on a rotating blade in k-space. On the other hand, the IDEAL technique was more useful for reducing the susceptibility artifacts. The use of a proper technique in clinical trials based on these results is expected to provide better clinical information for imaging diagnoses.     

Direct fabrication of graphene/zinc oxide composite film and its characterizations

Graphene-based composites represent a new class of materials with potential for many applications. Graphene can be attached to a metal, a semiconductor, or any polymer for enhancing properties. In this work, a new mixed dispersion approach for graphene-based composite has taken on. Graphene flakes (<4 layers) and a well-known semiconductor zinc oxide (ZnO) (<50 nm particle size) have dispersed in N-methyl-pyrrolidone. We deposited graphene/ZnO composite thin film by a simple, low-cost, environmentally friendly and non-vacuum electrohydrodynamic atomization process on silicone substrate. Experiments have been carried out by changing flow rate and applied potential while keeping stand-off distance and substrate velocity constant, to discover the optimum conditions for obtaining a high-quality thin film. It has been explored that high-quality thin composite film is obtained at optimum flow rate of 300 μl/h at 6.3 kV applied potential after curing for 2 h at 300 °C. Graphene/ZnO thin composite film has been characterized using Field emission scanning electron microscopy, Ultra-violet Visible near Infra Red spectroscopy, X-ray diffraction, Raman Spectroscopy and 3D-Nanomap. For electrical behavior analysis, a simple diode Indium tin oxide/(poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS)/polydioctylfluorene-benzothiadiazole(F8BT)/(Graphene/ZnO) has fabricated. It is observed that at voltage of 0.3 V, the current in organic structure is at low value of 1.20 × 10^?3 Amp/cm² and after that as further voltage was applied, the device current increased by the order of 110 and reaches up to 1.32 × 10^?1 Amp/cm² at voltage 2 V.     

Comparison of electrochemical performance for zinc anode via various electrolytes and conducting agents in Zn-air secondary batteries

Zn-air batteries have many advantages as energy devices but they show a poor charge-discharge cycle performance. Therefore, this study examined the effects of various types of electrolytes and conducting agents and changed the additive contents to optimize the electrochemical performance of Zn-air secondary batteries. Electrolytes, such as sodium hydroxide (NaOH) and potassium hydroxide (KOH) solutions, and conducting agents, such as super-p, denka black, acetylene black, and ketjen black, were used to increase the electric conductivity. The electrochemical performance of the zinc anode was evaluated from charge-discharge capacities and cycle efficiency. When the capacity was compared according to each electrolyte from one to ten cycles, in contrast, the zinc anode in 6 M KOH showed a higher discharge capacity in the first cycle. Therefore, zinc anode was composed in the 6-M KOH electrolyte and conducting agents were added. The zinc anode included conducting agents with a higher cycle capacity than those without conducting agents, and super-p had a higher first discharge capacity than the others. Therefore, the zinc anode with super-p of 4% shows the highest performance using 6 M KOH in Zn-air secondary batteries.