Venom Peptide Toxins Targeting the Outer Pore Region of Transient Receptor Potential Vanilloid 1 in Pain: Implications for Analgesic Drug Development

The transient receptor potential vanilloid 1 (TRPV1) ion channel plays an important role in the peripheral nociceptive pathway. TRPV1 is a polymodal receptor that can be activated by multiple types of ligands and painful stimuli, such as noxious heat and protons, and contributes to various acute and chronic pain conditions. Therefore, TRPV1 is emerging as a novel therapeutic target for the treatment of various pain conditions. Notably, various peptides isolated from venomous animals potently and selectively control the activation and inhibition of TRPV1 by binding to its outer pore region. This review will focus on the mechanisms by which venom-derived peptides interact with this portion of TRPV1 to control receptor functions and how these mechanisms can drive the development of new types of analgesics.     

Machinability of Silicon Nitride/Boron Nitride Nanocomposites

The machinability and deformation mechanism of Si₃N₄/BN nanocomposites were investigated in the present work. The fracture strength of Si₃N₄/BN microcomposites remarkably decreased with increased hexagonal graphitic boron nitride ( h -BN) content, although machinability was somewhat improved. However, the nanocomposites fabricated using the chemical method simultaneously had high fracture strength and good machinability. Hertzian contact tests were performed to clarify the deformation behavior by mechanical shock. As a result of this test, the damage of the monolithic Si₃N₄ and Si₃N₄/BN microcomposites indicated a classical Hertzian cone fracture and many large cracks, whereas the damage observed in the nanocomposites appeared to be quasi-plastic deformation.     

Fe3O4@SiO2@TiO2@PDA Nanocomposite for the Degradation of Organic Materials

In order to enhance the effectiveness of pollutant removal by photocatalysis under visible light, a multifunctional photocatalyst was prepared by grafting polydopamine (PDA) with the core-shell nanocomposite Fe₃O₄@SiO₂@TiO₂ (FST). The structural, morphological, and magnetic responses of FST@PDA were characterized by X-ray diffraction pattern, Fourier transform infrared spectroscopy, transmission electron microscopy, etc. FST@PDA showed a high degradation rate of rhodamine B, reaching 98.7 % and 95.7 % after 150 min of ultraviolet and visible light radiation, respectively. In addition, the prepared FST@PDA had good safety and high recyclability due to the strong covalent bonds between FST and PDA.     

Sinterability, mechanical, and electrical properties of Al2O3/8YSZ nanocomposites prepared by ultrasonic spray pyrolysis

Al2O3 nanoparticles added the YSZ for improving the mechanical property and the ionic conductivity. Al2O3/YSZ nanocomposites were prepared by ultrasonic spray pyrolysis and PECS process. The relative density of the Al2O3/YSZ nanocomposites was fully densified at a sintering temperature of 1100 degrees C. The grain size for 5 vol.% Al2O3/YSZ was less than 100 nm. The fracture toughness and total ionic conductivity of Al2O3/YSZ nanocomposites were improved compared with Al2O3/YSZ nanocomposites by conventional process, due to homogeneous dispersion and uniform particle size of added Al2O3.     

Nanoscale biofilm modification-method concerning a myoglobin/11-MUA bilayers for bioelectronic device

We developed surface modification tools for the fabrication of a bioelectronic device which consists of a myoglobin monolayer self-assembled on an 11-MUA layer. To utilize a single protein as the active element, it was necessary to reduce protein aggregation on the protein layer in the nanobio electronic device, which was developed in our previous study and shown to display basic biomemory functions. Here, the reduction of myoglobin aggregation was accomplished by using 3-(3-cholamidopropyl) dimethylammonio-11-propanesulfonate (CHAPS) to fabricate a well-defined protein layer on the bioelectronic device. We investigated two different surface modification methods for making well oriented biofilm. The effects of CHAPS on the formation of a myoglobin layer self-assembled on an 11-MUA layer were examined by atomic force microscopy and Raman spectroscopy. The size of the myoglobin aggregates was reduced from 200-250 nm to 10-40 nm depending on treatment method. The sustaining redox property of the CHAPS treated myoglobin layer was examined using cyclic voltammetry. Using these techniques, we found that after surfactant CHAPS treatment, protein aggregation was dramatically reduced and the protein layer still maintained its inherent electrochemical properties.     

Evaluation of recirculation sump performance for OPR1000 plant: Part I debris transport during the blow-down phase of LOCA

After TMI-2 accident, long-term core cooling management takes more importance rather than short-term management since probabilistic safety assessment performed revealed that long-term management had higher risk than the risk from short-term management. Regarding to this, since 1992, blockage of sump suction strainer was taken a place in Barseback Unit 2 (Sweden, BWR) and the United States Nuclear Regulatory Commission (USNRC) took into consideration as a General Safety Issue 191 (GSI-191), “PWR Sump Blockage,” in 1998 and opening an investigation.As a response to GSI-191 the Nuclear Energy Institute (NEI) submitted a recirculation sump evaluation methodology called NEI 04–07. In this methodology 0.75 was recommended for blow-down transport to lower containment based on the study on a boiling water reactor sump clogging issue and engineering judgment. USNRC quantitatively evaluated the blow-down transport in the safety evaluation report to NEI 04–07, and concluded the recommended blow-down transport fraction in NEI 04–07 was sufficiently conservative. However, the safety evaluation report to NEI 04–07 includes many values in evaluation steps which depend much on the containment configuration and engineering judgment. In particular the dependency on the plant type limits the generality of the USNRC’s conclusion on blow-down transport, when the considered plant is different from the volunteer plant.This study provides a modified evaluation method and results of debris blow-down transport for an Optimized Power Reactor 1000 MWe (OPR1000) in Korea. The modified method includes more realistic physical background with less uncertainty while providing consistent result with NEI and USNRC methods.     

Estimation of exposure dose for decontamination workers from contaminated soil at a nuclear decommissioning site in Korea

Assessment of the exposure dose for workers is crucial to protecting workers from the radiological risk.This preliminary study estimates the potential radiological exposure for a soil remediation worker at a nuclear decommissioning site contaminated with Cs-137 in Korea,and then calculates the maximum workable soil concentration to comply with the occupational dose constraint of 20 mSv per year.The Korean characteristic data,detailed exposure scenarios for workers by the type of work,and relevant exposure pathways were used in the dose estimation.As a result,the most severe exposure-induced work type was identified as the excavator operation with an annual individual dose of 5.92×10^-5 mSv for a unit concentration of soil,from which the derived maximum workable soil concentration was 3.38×10⁵ Bq/kg.Furthermore,dose contribution by each exposure pathway was found to be decreased in the following order:external radiation exposure,soil ingestion,dust inhalation,and skin contamination.The results of this study are expected to be used effectively to optimize radiation protection for workers and establish appropriate work procedures for future site remediation.     

Laser soldering for chip-on-glass mounting in flat panel display application

Chip-on-glass (COG) mounting of area array electronic packages was attempted by heating the rear surfrace of a contact pad film deposited on a glass substrate. The pads consisted of an adhesion (i.e., Cr or Ti) and a top coating layer (i.e., Ni or Cu) was heated by an UV laser beam transmitted through the glass substrate. The laser energy absorbed on the pad raised the temperature of a solder ball which was in physical contact with the pad, forming a reflowed solder bump. The effects of the adhesion and top coating layer on the laser reflow soldering were studied by measuring the temperature profile of the ball during the laser heating process. The results were discussed based on the measurement of reflectivity of the adhesion layers. In addition, the microsctructures of solder bumps and their mechanical properties were examined.     

The effect of parameters on the formation of ZnO nanoparticles by statistical experimental design method in vibrating milling process

Zinc oxide (ZnO) nanoparticles were synthesized by vibrating milling process. Amorphous ZnO powders prepared by the milling process were washed with water to remove NaCl, and then the powders were sintered at 300–500 °C for 2 h. In this work, statistical experimental design method was used and it was found that the particle size and size distribution of ZnO nanoparticles were dependent on the milling time and mass ratio of ball to powder. Therefore, ZnO nanoparticles with about 100 nm of mean crystallite size were obtained.     

Transport properties of Bi<Subscript>43</Subscript>Se<Subscript>4</Subscript>Te<Subscript>53</Subscript> thermoelectric alloy fabricated by mechanical grinding and pulse discharge sintering

Mechanical grinding followed by pulse discharge sintering was applied to fabricate n-type Bi₄₃Se₄Te₅₃ thermoelectric materials. Calorimetric measurements demonstrated that a Se-rich phase was developed from Bi₂(Se, Te)₃ phase after 10h of milling. However, when the milling time was extended to 25 h or longer, a Te-rich phase was formed. Hall measurements showed that the development of the Se/Te-rich phase considerably increased the carrier concentration but decreased the carrier mobility. The oxygen contamination in the smashed powders was also an important consideration for the degeneration of the figure of merit of the sintered samples.