New-type of Multi-purpose Standard Radon Chamber in South Korea

Radon is an inert and a radioactive gas which is colorless, tasteless and odorless. As the radon decay proceeds, and if DNA damage continues beyond repair capacity of cells in the human body, it can cause severe health problems such as lung cancer in the long-term. There is a tendency that those countries where legal restriction on radon is strict, various studies related to radon are under way. In South Korea, radon has been regulated under recommendation level. Even though there are about 3 standard radon chambers in Korea, they have not been in an active use because of lack of demand. Also, most of them are specialized in calibration of radon detectors only. Recently, Korean government started giving some attention to radon issue and supporting radon research fields. Thus, this study was carried out to develop a new type of radon chamber for multi-purpose such as 1) radon emission rate from natural and artificial radon sources; 2) calibration of radon detectors; 3) evaluation of radon mitigation efficiency. Keywords: Radon, Radon Chamber, Indoor Air Quality, Chamber Desig

Central peaks, acoustic modes, and the dynamics of polar nanoregions in Pb[(Zn1/3Nb2/3)xTi1−x]O3 single crystals studied by Brillouin spectroscopy

Temperature dependence of acoustic behaviors and quasielastic central peaks (CPs) of Pb[(Zn1/3Nb2/3)xTi1−x]O3 (PZN-xPT) single crystals with x=4.5% and 9% have been investigated in a temperature range of 300–900 K by using the Brillouin light scattering. The temperature dependence of the C11 elastic constant of both crystals showed a deviation from normal lattice anharmonicity at the Burns temperature (TB) of about 730 K upon cooling, indicating the onset of the electrostrictive coupling between the polar nanoregions (PNRs) and the longitudinal acoustic (LA) waves. Upon further cooling, depolarized CP began to appear at a certain temperature (Td) located in 500–550 K, which was accompanied by substantial softening of the C44 elastic constant below this temperature suggesting anisotropic electrostrictive coupling between PNRs and the two acoustic waves. In addition, the onset of significant increase in the acoustic damping of both acoustic waves at Td could be seen from the temperature dependence of the linewidth of Brillouin doublets. These results suggested that electrostrictive coupling of the strain to the square of the local polarization of PNRs and the resultant order-parameter fluctuations are enhanced not at TB but at a much lower temperature of Td, which may be ascribed to a local structural transformation occurring in PNRs at Td. This suggestion is consistent with recent studies on PZN-xPT single crystals reporting the appearance of strong acoustic emission signals [M. Roth et al., Phys. Rev. Lett. 98, 265701 (2007)] and substantial changes in the Raman spectrum [O. Svitelskiy, Phys. Rev. B 72, 172106 (2005)] at almost the same temperature. From the comparison of the present results to those of two typical relaxors, Pb(Mg1/3Nb2/3)O3 and Pb(Mg1/3Ta2/3)O3, it was suggested that the existence of an intermediate characteristic temperature Td below TB may be considered as a more common characteristic in the temperature evolution of PNRs of relaxor ferroelectrics

Enhancement on Radon Adsorption Property of GAC using Nano-size Carbon Colloids

Granular activated carbon (GAC) is well-known as an efficient adsorbent against a number of gaseous pollutants. Radon is one of those pollutants, and radon has been classified as the second leading cause of lung cancer in USA. This study was to enhance the radon removal efficiency with applying nano-technology. Nano-size carbon colloids (NCC) was produced through electrolysis which is simple and cheap. NCC was used for impregnation with activated carbon. Surface areas of both NCC-treated and non-treated activated carbon did not show a significant difference. However, the results of radon removal efficiency show that impregnated carbon with NCC could capture about 1.3 ~ 2 times of more radon gas compared to non-treated activated carbon. It is assumed that nano-size carbon colloids might have filled up meso-pores, and meso-pores turned into micro-pores eventually. Because meso-pores initially accounted for large portion of whole pores, more radon could be captured to NCC-impregnated activated carbon. Keywords: Radon, Nano-Size Carbon Collid, Activated Carbo

Ruin Theory for User Association and Energy Optimization in Multi-access Edge Computing

In this letter, a novel framework is proposed for analyzing data offloading in a multi-access edge computing system. Specifically, a two-phase algorithm, is proposed, including two key phases: \emph{1) user association phase} and \emph{2) task offloading phase}. In the first phase, a ruin theory-based approach is developed to obtain the users association considering the users' transmission reliability. Meanwhile, in the second phase, an optimization-based algorithm is used to optimize the data offloading process. In particular, ruin theory is used to manage the user association phase, and a ruin probability-based preference profile is considered to control the priority of proposing users. Here, ruin probability is derived by the surplus buffer space of each edge node at each time slot. Giving the association results, an optimization problem is formulated to optimize the amount of offloaded data aiming at minimizing the energy consumption of users. Simulation results show that the developed solutions guarantee system reliability under a tolerable value of surplus buffer size and minimize the total energy consumption of all users.Comment: This paper has been submitted to IEEE Wireless Communications Letter

Microheterogeneity and field-cooling effects on Pb[(Zn1/3Nb2/3)0.955Ti0.045]O3 single crystals probed by micro-Brillouin scattering

Microheterogeneity and field-cooling effects were investigated on Pb[(Zn1/3Nb2/3)0.955Ti0.045]O3 (PZN-4.5%PT) single crystals by using a high-resolution micro-Brillouin scattering. The temperature dependence of Brillouin shift showed a typical relaxor behavior with marked softening on approaching the diffuse phase transition, but also revealed a clear microareal variation in a rhombohedral phase below 150 °C which means a heterogeneity exists over a length scale of at least a few microns in PZN-4.5%PT. These two features seem to correlate with the coexistence of both micronsized domains and irregular nanosized domains, recently confirmed by high-resolution domain studies. This complex domain structure may make each microdomain represent different relaxor behaviors due to its own polar nanoregions and their dynamics. When the crystal was cooled under the electric field along the [001] direction from a cubic phase, two field-induced changes were observed in the Brillouin shift at around 143 °C and 106 °C. This observation is in good agreement with the dielectric measurements, meaning a medium-range ordered phase exists between short-range ordered and long-range order phases

Hysteresis in acoustic properties of ferroelectric relaxor Pb[(Zn1/3Nb2/3)0.955Ti0.045]O3 single crystals studied by Brillouin and dielectric spectroscopies

Acoustic and dielectric properties of Pb[(Zn1/3Nb2/3)1–xTix]O3 (PZN-xPT) single crystals with x=0.045 have been studied by the high-resolution micro-Brillouin scattering and dielectric spectroscopy in a wide temperature range. The softening of the Brillouin shift and the increase of dielectric relaxation time upon cooling indicated the formation of polar nanoregions (PNRs) and the slowing down of their dynamics. In contrast to the acoustic properties of typical model relaxors such as lead magnesioniobate, the change in the Brillouin shift near its minimum became sharper on heating compared to the change on cooling, pointing to the clear existence of hysteresis in the dynamics of the diffuse phase transition in PZN-4.5%PT. Since the number of PNRs will increase upon cooling, it may be expected that the kinetics of the phase transition would become slower, the lower the transition temperature resulting in the more sluggish, broad feature of the Brillouin shift observed during cooling. This result may indicate that the number and size of polar nanoregions, which are dependent on temperature, play an important role in the development of the mesoscopic ferroelectric order in PZN-4.5%PT

Evaluation of the efficacy of ivermectin against Theileria orientalis infection in grazing cattle

Background Raising cattle on pastures is known to be beneficial for animal welfare and cost reduction. However, grazing is associated with the risk of contracting tick-borne diseases, such as theileriosis. Here, the efficacy of ivermectin against these diseases and associated clinical symptoms were evaluated. Results A total of 68 cattle from a grazing cattle farm were selected and divided into two groups: the control group (17 cattle) with no preventive treatment and the ivermectin-treated group (51 cattle) in which cattle were treated with pour-on ivermectin prior to grazing. The infection rates of Theileria orientalis and the red blood cell (RBC) profile (e.g., RBC count, hematocrit value, and hemoglobin concentration) were compared in the spring (before grazing) and summer (during grazing) between the two groups. Based on PCR amplification of the major piroplasm surface protein (MPSP) gene, 12 cattle were positive for T. orientalis infection. Phylogenetic analysis revealed that the isolates identified in this study consisted of three MPSP types (1, 2, and 7). The T. orientalis infection rate in the control group during grazing was 3-fold higher than that in the ivermectin-treated group. Moreover, differences in RBC parameters during grazing were greater in the control group than in the ivermectin-treated group. In particular, the hematocrit value was significantly reduced in the control group. Conclusions The results of this study demonstrated that ivermectin had protective effects against T. orientalis infection and RBC hemolysis in grazing cattle.This work was supported by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea (NRF2017R1A2B2005685). This research was partially supported by Technology Development Program (Project No. 1116043–1) for Bio-industry, Ministry for Agriculture, Food and Rural Affairs, Republic of Korea. The funders had no role in the study design, data collection and analysis, interpretation of results, writing of the report, decision to submit the paper for publication

Analysis of triterpenoids, carotenoids, and phenylpropanoids in the flowers, leaves, roots, and stems of white bitter melon (Cucurbitaceae, Momordica charantia)

Purpose: To evaluate the contents of carotenoids, triterpenoids, and phenylpropanoids in different parts of white bitter melon.Methods: We evaluated the accumulation of 2 triterpenoids, 10 carotenoids, and 11 phenylpropanoids in different parts of white bitter melon, including fruits at four different developmental stages using HPLC.Results: Charantin, lutein, and rutin were the main triterpenoids, carotenoids, and phenylpropanoids, respectively. The accumulation of triterpenoids (momordicine and charantin), carotenoids (antheraxanthin, lutein, violaxanthin, α-carotene, and β-carotene), and phenylpropanoids (caffeic acid, chlorogenic acid, epicatechin, gallic acid, p-coumaric acid, rutin, and trans-cinnamic acid) was high inthe leaves and/or flowers, which are exposed to direct sunlight, but low in the roots.Conclusion: Most of the analyzed components were accumulated at high levels in the leaves and/or flowers. These results will help exploit the compounds in various parts of white bitter melon that are beneficial for human health. Keywords: Momordica charantia, Bitter melon, Triterpenoid, Carotenoid, Phenylpropanoi