In this study, we examine the relationships between the National Oceanic and Atmospheric Administration (NOAA) space weather scale frequencies and the maximum monthly sunspot number in each solar cycle: 1975 to 2020 for radio blackouts (R scales) and solar radiation storms (S scales), 1932 to 2020 for geomagnetic storms (G scales). Our main results are as follows. First, we find that NOAA space weather scale frequencies have strong solar cycle dependencies. Second, we propose new linear relationships between the frequency of certain scales (R1 to R4, and G1 to G4) and the maximum monthly sunspot number. T-test results show that R1 to R3 and G1 to G4 relationships are statistically meaningful, but marginal for R4. Third, our results significantly reduce the root-mean-square error (RMSE) between observed and suggested frequencies compared to the NOAA’s current frequencies. For example, in the case of solar cycle 24, our new prediction (74) for R3 scale is much more consistent with the observational frequency (74) than the NOAA prediction (175), and our prediction (85) for G3 scale is much closer to the observation (40) than the NOAA prediction (200). Our work may provide a useful guideline for advancing the space weather scales.

급성 뇌경색 진단에는 환자에 따라 관류강조영상과 조영증강 자기공명혈관영상이 동시에 촬영되는 경우가 있으며, 이 과정에서 MRI 조영제인 가돌리늄의 T1 단축 효과가 발생하여 동맥과 정맥의 신호 겹침이 빈번히 발생한다. 특 히, 3D T1 경사에코 기법을 사용한 CE-MRA에서 첫 번째 조영제 주입(PWI) 후 연속적으로 발생하는 T1 감소 효과로 인해 혈관의 정확한 묘사에 한계가 있었다. 본 연구에서는 이러한 문제를 해결하기 위해 마스크 영상의 획득 시점을 조정하여 새로운 방법(B)을 제안하였다. 기존 방법(A)에서는 관류강조영상 이전에 마스크 영상을 획득했지 만, 새로운 방법(B)에서는 관류강조영상 이후 마스크 영상을 획득하여 동맥과 정맥 신호 겹침을 효과적으로 줄였다. 연구 결과, S상 정맥동과 내경정맥에서 새로운 방법이 기존 방법보다 유의미하게 낮은 대조대잡음비를 보였으며, 신호 겹침이 줄어들어 정맥 신호의 억제 효과가 극대화되었다(p<0.05). 본 연구의 새로운 방법은 기술적으로 추가적 인 복잡성 없이 효율적으로 정맥 신호를 제거하여 CE-MRA 영상의 진단적 정확성을 향상하는 유용한 기법으로 평 가된다. 향후 연구에서는 더 다양한 환자군을 대상으로 본 방법의 유용성을 검증하고, 최적의 방안 모색을 할 필요가 있다.

Background: In healthy dentin conditions, odontoblasts have an important role such as protection from invasion of pathogens. In mammalian teeth, progenitors such as mesenchymal stem cells (MSCs) can migrate and differentiate into odontoblast-like cells, leading to the formation of reparative dentin. For differentiation using stem cells, it is crucial to provide conditions similar to the complex and intricate in vivo environment. The purpose of this study was to evaluate the potential of differentiation into odonto/ osteoblasts, and compare co-culture with/without epithelial cells. Methods: MSCs and epithelial cells were successfully isolated from dental tissues. We investigated the influences of epithelial cells on the differentiation process of dental pulp stem cells into odonto/osteoblasts using co-culture systems. The differentiation potential with/without epithelial cells was analyzed for the expression of specific markers and calcium contents. Results: Differentiated odonto/osteoblast derived from dental pulp tissue-derived mesenchymal stem cells with/without epithelial cells were evaluated by qRT-PCR, immunostaining, calcium content, and ALP staining. The expression of odonto/ osteoblast-specific markers, calcium content, and ALP staining intensity were significantly increased in differentiated cells. Moreover, the odonto/osteogenic differentiation capacity with epithelial cells co-culture was significantly higher than without epithelial cells co-culture. Conclusions: These results suggest that odonto/osteogenic differentiation co-cultured with epithelial cells has a more efficient application.

The increase in the use of artificial intelligence (AI) in the workplace has introduced changes to traditional working environments. However, these are changes not only to employee productivity but also to how employees feel and think about their work. Based on prior research that has suggested connections between employees’ perceptions of AI and their emotions and thoughts at work, the present study tested a moderated mediation model in which the perception of AI opportunity is indirectly related to job insecurity via employee hope, with tenure as a moderator. Data obtained from 290 Korean full-time employees illustrated that the perception of AI opportunity was negatively related to job insecurity through hope acting as a mediator. In addition, this indirect relationship was found to be dependent on the moderating role of tenure. Specifically, at lower levels of tenure, the aforementioned indirect relationship was statistically significant, but at higher levels of tenure, this indirect relationship was no longer found to be statistically significant. The implications, limitations, and future research directions of this study are discussed.

Pollination is an important ecosystem service mostly provided by diversity of pollinating insects and other animals. As in the anthropocene biodiversity crisis with the climate change, pollination systems are experiencing strongly challenged such as pollinator diversity and abundance decline, pollinator health weakness, pollinator-plant network instability as well as the crop-pollinator habitat fragmentation and insuitability. Here we present some research progress conducted from our group in the last decade. As the pollination dependence of Korean agriculture increases, pollination contribute ap. one forth of national agricultural production, and is responsible substantial portion of vitamin and mineral provisioning. Pollinator diversity is declining in various crop systems and network connectivity is decreasing. Still in agricultural landscape, honeybee (Apis spp) is the main pollinator, accounting ap. 70% of bees, and showed the possible resource partitioning between the native, A. cerana and the introduced, A. mellifera. Simulation of crop-pollinating insect distribution suitability showed up and down directional responses, but more on the negative Further research area for better understanding and stabilizing the plant-pollinator system was proposed.