http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
코로나바이러스감염증-19의 사회적 거리두기 상황에서 한국 대학생의 신체활동, 사회활동 수준 및 우울 증상과의 관계에 대한 조사연구
전세현(Chon, SaeHyun),이서희(Lee, SeoHee),배은지(Bae, EunJi),김진실(Kim, JinShil) 전남대학교 간호과학연구소 2021 Nursing and Health Issues(NHI) Vol.26 No.1
Purpose: This study aimed to examine the depressive symptoms of college students associated with the limited physical and social activities during the coronavirus disease 2019 (COVID-19) pandemic. Methods: A web-based survey was conducted with a standardized e-questionnaire generated using the Google form. The web-link was distributed to college students through the social media platform, Facebook, to obtain data on the levels of physical and social activities and depressive symptoms owing to strict social distancing measures adopted for coronavirus prevention. Physical and social activities and depressive symptoms were assessed by the Korean version of the International Physical Activity Questionnaire-Short Form, measured on a 0-to-100 numerical rating scale, and Center for Epidemiology Studies Short Depression Scale, respectively. Results: A total of 261 university students participated in this survey. The median score of depressive symptoms was 3.0 (IQ1,3=2.0, 5.0), with 61.3% experiencing depression using the cut-off point≥3. The levels of physical activity were classified as level 1(inactive group), 27.2%, level 2 (minimally active group), 42% to level 3 (health-enhancing group), 29.9%. Depressive symptoms were not significantly different by physical activity levels (H=5.01, p =.081). The median score of perceived restriction in social activity was 70.0 (50.0, 80.0), suggesting that increased perceived social activity restriction was associated with increased likelihood of depression (OR=1.012, CI=1.001, 1.023). Conclusion: Owing to social distancing during the COVID-19 pandemic, depressive symptoms in college students were substantial. Notably, depressive symptoms increased with more perceived restrictions in social activity, suggesting the urgent need to address college students mental health during this global crisis of the COVID-19.
The Dehydration Process and Evaluation of NaCl-MgCl2 Using Elemental Mg
Jihun Kim,Wonseok Yang,Saehyun Choi,Wonseok Lee,Taeho Jang,Sungyeol Choi 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1
Molten salt reactors have several advantages over conventional light water reactors. These include producing less nuclear waste, operating at higher power efficiency and inherent safety due to the low operating pressure. NaCl-MgCl2 eutectic salt is one of the candidates for the molten salt reactor coolant. However, because the salt is very hygroscopic, structural material corrosion occurs resulting in the high cost to maintain. To mitigate corrosion there have been many studies for the dehydration of the salt, especially focusing on the magnesium chloride. The reason is that the moisture adsorbed to the magnesium chloride undergoes hydrolysis over 200 degrees Celsius and decomposes to MgOHCl while the moisture associated with the NaCl is easily liberated during the heating procedure without chemical reaction. As the operating temperature of the molten salt is between 500 and 700 degrees Celsius, the MgOHCl is believed as the main cause for the structural corrosion. In this research, thermal dehydration of the salt with elemental Mg, for the NaCl-MgCl2 eutectic, was studied based on the previous dehydration methods and considering scalable and easy to handle. The MgOHCl was removed both through the thermal decomposition and the reduction by Mg metal. After the removal of MgOHCl, based on the difference between the freezing points and the density, the salt cooled down very slowly to ensure the separation between the purified salt and the disposals such as MgO and remaining Mg metals. The efficiency of the dehydration method was determined by the concentration of the MgOHCl. The concentration was determined by cyclic voltammetry and the result was compared with undehydrated salt and salt dehydrated thermally without the addition of Mg metal. To qualify and quantify the MgOHCl content through the cyclic voltammetry, it was necessary to observe the signal by adding MgOHCl to each sample. Based on the thermogravimetric analysis result of MgCl2· 6H2O, MgOHCl powder was formed through heating the MgCl2·6H2O.
Unusual size-dependence of effective interactions between collapsed polymers in crowded environments
Oh, Inrok,Choi, Saehyun,Jung, YounJoon,Kim, Jun Soo The Royal Society of Chemistry 2014 SOFT MATTER Vol.10 No.45
<P>We investigate the influence of macromolecular crowding on interactions between collapsed polymers using computer simulations, to gain insights into biomacromolecular interactions in crowded biological environments. The effective attraction is induced between two collapsed polymers due to the macromolecular crowding, and it is found that the strength of the effective attraction decreases as the crowder size is reduced for a fixed crowder volume fraction, which is sharply contrasted with the conventional viewpoint based on the depletion attraction observed for hard-core spherical colloids. This unusual trend of size-dependence is interpreted by dividing the effective interaction into the polymer-mediated repulsion and crowder-mediated attraction. It is found that the ranges of repulsive and attractive contributions overlap significantly due to the flexible nature of polymer boundaries, resulting in partial cancellation over this range which leads to the observed size-dependence. Thus, this work suggests that the effective interactions between biomacromolecules in crowded environments may be qualitatively different from the depletion interactions predicted for hard-core spherical colloids.</P> <P>Graphic Abstract</P><P>Size-dependence of depletion attraction on collapsed polymers. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4sm01486c'> </P>
Lee, Yoonjung,Yoon, Eojin,Cho, Saehyun,Schmä,hling, Sigrun,Mü,ller, Jü,rg,Song, Ji-Joon Elsevier 2019 Structure Vol.27 No.5
<P><B>Summary</B></P> <P>Human ASH1L is the catalytic subunit of the conserved histone methyltransferase (HMTase) complex AMC that dimethylates lysine 36 in histone H3 (H3K36me2) to promote gene transcription in mammals and flies. Unlike AMC, ASH1L alone shows poor catalytic activity, because access to its substrate binding pocket is blocked by an autoinhibitory loop (AI loop) from the postSET domain. We report the crystal structure of the minimal catalytic active AMC complex containing ASH1L and its partner subunit MRG15. The structure reveals how binding of the MRG domain of MRG15 to a conserved FxLP motif in ASH1L results in the displacement of the AI loop to permit substrates to access the catalytic pocket of the ASH1L SET domain. Together, ASH1L activation by MRG15 therefore represents a delicate regulatory mechanism for how a cofactor activates an SET domain HMTase by releasing autoinhibition.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Crystal structure of ASH1L_MRG15 complex was determined </LI> <LI> MRG15 binding to ASH1L releases the autoinhibitory loop </LI> <LI> MRG15 binding to ASH1L activates ASH1L histone methyltransferase activity </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>