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In this study, an electron-scattering device was fabricated to practically use the ultra-high dose rate electron beams for the FLASH preclinical research in Dongnam Institute of Radiological and Medical Sciences. The Dongnam Institute of Radiological and Medical Sciences has been involved in the investigation of linear accelerators for preclinical research and has recently implemented FLASH electron beams. To determine the geometry of the scattering device for the FLASH preclinical research with a 6-MeV linear accelerator, the Monte Carlo N-particle transport code was exploited. By employing the fabricated scattering device, the off-axis and depth dose distributions were measured with radiochromic films. The generated mean energy of electron beams via the scattering device was 4.3 MeV, and the symmetry and flatness of the off-axis dose distribution were 0.11% and 2.33%, respectively. Finally, the doses per pulse were obtained as a function of the source to surface distance (SSD); the measured dose per pulse varied from 4.0 to 0.2 Gy/pulse at an SSD range of 20–90 cm. At an SSD of 30 cm with a 100-Hz repetition rate, the dose rate was 180 Gy/s, which is sufficient for the preclinical FLASH studies.

본 연구는 최저임금 인상에 대한 다양한 논란과 관심 속에서 최저임금인상이 기업의 고용과 생산성에 어떠한 영향을 미치는지를 실증적으로 분석함으로써 최저임금인상의 경제적 효과를 이해하고, 최저임금 인상에 대한 정책적 시사점을 제시하고자 한다. 이를 위해 본 연구에서는 한국노동연구원의 사업체패널조사 자료와 통계청의 고용형태별근로실태조사 자료를 활용해 고용규모별, 산업별 최저임금 영향률을 추정하고, 이를 생산성과 연계해 최저임금 인상이 기업 생산성에 미치는 영향을 분석하였다. 분석결과, 첫째, 고용규모별 최저임금 영향률은 기업의 고용을 감소시키지만 근로자의 평균임금을 상승시키고, 기업의 생산성을 증가시켰다. 둘째, 산업별 최저임금 영향률은 기업 고용에 정((+)의 영향을 미치지만 기업의 생산성에 통계적으로 유의한 영향을 미치지 못하였다. 셋째, 고용규모별 Kaitz 지수는 평균임금 변화 대비 최저임금 상승폭이 클수록 기업 생산성에 긍정적인 영향을 미치는 반면 산업별 Kaitz 지수는 기업 생산성에 부정적인 영향을 미친다. 넷째, 최저임금근로자의 고용비중은 기술진보 효과를 통해 기업 생산성을 증가시키는 반면 Kaitz지수는 기술 효율성의 개선을 통해 기업의 생산성을 향상시킨다. 마지막으로 자산규모와 주가지수상승률은 기업의 생산성에 긍정적인 영향을 미치는 반면 임금상승률, 자본집약도, 물가상승률과 전기의 총요소생산성은 부(-)의 영향을 보였다.

We report newly synthesized fluorescence resonance energy transfer (FRET)-based green-, red-, and near-infrared (NIR)-emitting polymer dot (Pdot) probes. Fluorescent Pdots (∼60 nm) were prepared wi...

A uniform electron field is required for medical applications of electron linear accelerators (LINACs). Electron irradiation devices, including scattering foils and applicators for generating uniform electron fields, are widely used in medical LINACs. In this research, an electron scattering device consisting of scattering foils and applicators was designed for clinical application of a 9-MeV electron LINAC planned at the Dongnam Institute of Radiological & Medical Sciences. Monte Carlo simulations were performed to calculate the depth dose and the beam profile curves in a water phantom by using the EGSnrc Monte Carlo code.

A 9-MeV electron linear accelerator based on C-band microwaves for medical applications is being assembled at the Dongnam Institute of Radiological and Medical Sciences (DIRAMS). The accelerating column has an on-axis coupled structure and will be operated with a π/2-mode standing wave. Parameters of the cavities are selected based on simulations with CST MICROWAVE STUDIO® (CST MWS), and the cold test and micro-machining are performed to obtain the desired RF characteristics of the cavity. Then, the bead-pull test is conducted to measure the RF properties of the full accelerating column structure. The fabrication of the C-band accelerating column and the results of the low-power RF tests are discussed.

The 6-MeV C-band standing-wave accelerator was constructed in 2015 and is providing for the beam service. The new 9-MeV accelerator was designed and constructed in 2018 at the Dongnam Institute of Radiological & Medical Sciences (DIRAMS), Busan, Korea. The 5712 MHz accelerating column was designed with an average accelerating gradient of 16.7 MV/m at a pulsed resonance frequency (RF) power of 2.5 MW. The C-band coaxial magnetron was chosen for its high RF power of 2.5 MW and RF frequency of 5712 ± 10 MHz. While the 6-MeV accelerator was operating using a magnetron manufactured by BVERI, China, the 9-MeV accelerator uses a magnetron manufactured by CPI, USA. Though the CPI magnetron requires more heating power and precise heating control for high repetition operation, the frequency spectrum and the RF power distribution are satisfactory for our accelerating columns. The magnetron installed on the 9-MeV accelerator was tested with the 6-MW pulse modulator based on the thyratron-switched pulse-forming network and is currently operating for accelerator RF conditioning. In this paper, we present a brief description of the 9-MeV accelerator, the integration of the RF transport systems and the commissioning status. We also discuss the results obtained during the early commissioning and future plan.

The fate and transport of microplastics (MPs) during deep bed filtration were investigated using combined laboratory experiments and numerical modeling. A series of column experiments were conducted within the designated ranges of six operating parameters (i.e., size of the MP and collector, seepage velocity, porosity, temperature, and ionic strength). A variance-based sensitivity analysis, the Fourier amplitude sensitivity test, was conducted to determine the priority in affecting both the attachment coefficient at the pore scale, and the subsequent stabilized height of the breakthrough curve at the continuum scale, which follows non-monotonic trends with singularity in the size of MP (i.e., 1 µm). Finally, Damkohler numbers were introduced to analyze the dominant mechanisms (e.g., attachment, detachment, or straining) in the coupled hydro-chemical process. The robustness of conceptual frameworks bridges the gap between pore-scale interactions and the explicit MPs removal in the continuum scale, which could support decision-making in determining the priority of parameters to retain MPs during deep bed filtration.

The control of the immune system of pigs after weaning is important in pig farming because productivity depends on the survival of the post-weaned pigs. Previously, antibiotics would have been administered in the case of infectious diseases to increase the survival rate of post-weaned pigs, but now, the use of antibiotics is strictly restricted in order to prevent other problems such as the occurrence of antibiotic-resistant pathogens. In this study, the effect of fermented kefir as a functional feed additive as a replacement to antibiotics was evaluated in terms of the microbial profile in fecal samples, immunological factors in the blood of pigs, growth performance measured as average daily gain (ADG) and the feed conversion rate (FCR) of post-weaned pigs. In the kefir-treated group, the number of lactic acid bacteria and Bacillus spp. in the fecal samples of the pigs increased with the kefir treatments. Interestingly, the number of coliform groups as opportunistic pathogens was reduced in the fecal samples of pigs treated with kefir. We found out that treatment with kefir enhanced the innate immunity of post-weaned pigs though the reduction of IL-6 as a proinflammatory cytokine and an increase in IgG as an immunoglobulin, enhancing immunological defense against pathogens. Finally, after treatment with kefir, we observed that the ADG of post-weaned pigs increased to 135.6% but FCR decreased to 92.2%. Therefore, this study shows that fermented kefir can be used as a functional feed additive and an antibiotic alternative in order to improve both the innate immune system and growth performance of post-weaned pigs.

Litopenaeus vannamei, known as whiteleg shrimp, is susceptible to infection by pathogenic microorganisms such as viruses and bacteria. Therefore, the prevention of infections in this shrimp is important to regulate the outbreaks of pathogenic microorganisms. In this study, we investigated the effects of kefir as a functional feed additive on innate immunity, survival against WSSV (White Spot Syndrome Virus) and productivity of L. vannamei. As a result, the treatment of kefir could upregulate six of seven genes crucial for innate immunity of L. vannamei. Also, the treatment of kefir directly improved the survival rate of L. vannamei against WSSV infection. Finally, in order to determine whether kefir can improve the productivity of shrimp, we carried out field tests in three aquaculture farms in South Korea. The weight of shrimp fed kefir was increased by 120% as well as the length, compared with that of the control group. These results demonstrate that kefir can be utilized as a functional feed additive to improve both innate immunity and productivity of L. vannamei in shrimp farming with no use of antibiotics.

This study evaluates occurrence of progressive bone loss (PBL) around implants with different implant surfaces.Retrospective examination of 2,517 implants was performed in 903 patients, including 1,147 anodized-surface implants in 454 patients and 1,370 resorbable blasting media (RBM)-surface implants in 449 patients, which were placed from January 2006 to December 2010. Through regular check-up radiographs and records, presence of PBL (up to50% of fixture length) was investigated. Implant removal for any reason was regarded a failure.In total, 2,186 implants (979 anodized implants and 1,207 RBM implants) in 793 patients were included in this study. PBL was more frequently observed among anodized implants (n = 36 in 21 patients; 4%) than among RBM implants (n = 19 in 14 patients; 2%), and this difference was statistically significant (P0.001). Occurrence of PBL was significantly influenced by surface modification and implant diameter (odds ratio [OR] of anodized surface = 4.40, 95% confidence interval [CI] = 1.78 to 10.89, P = 0.001; OR of wide implants = 9.62, 95% CI = 1.13 to 81.68, P = 0.038; determined by mixed-effects logistic regression analysis with random patient effect). However, total survival rate was significantly influenced by implant diameter and not by surface modification (P = 0.019), although effect of implant diameter was observed to be significant on anodized implants (P = 0.030).Implant surface modification and implant diameter are significantly associated with occurrence of PBL.

As the resolution of the image display devices has been diversified, the image interpolation methods has played a more important role. The cubic convolution interpolation method has been widely used because it is simple but it has no limitation of using and a good performance. This paper suggests an adaptive method to the cubic convolution interpolation. Considering the difference of the neighbored pixels values to a prediction pixel, a parameter value in the cubic convolution interpolation kernel is chosen.

International audience; The morphological studies of neuron structures are of great interests for biologists. However, manually detecting dendrites structures is very labor intensive, therefore unfeasible in studies that involve a large number of images. In this paper, we propose an automated neuron detection and description method. The proposed method uses ratios of probability maps from random walk sessions to detect initial seed-points and minimal cost path integrals with Delaunay triangulations.