• 수면정신생리
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• 제20권2호
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• pp.69-74
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• 2013

목 적 : 의학전문대학원 학생들은 과도한 학업으로 인해 수면 시간이 부족하고 수면의 질이 낮다고 알려져 있다. 본 연구는 의학전문대학원 학생의 수면 양상 및 이와 연관이 있을 것으로 생각되는 심리적 문제를 조사하였다. 방 법 : 부산대학교 의학전문대학원 1~4학년 학생 352명을 대상으로 수면 양상, Pittsburgh sleep quality index(PSQI), Epworth sleepiness scale(ESS), global assessment of recent stress scale(GASS), the center for epidemiologic studies-depression scale(CES-D), and Moudsley obsessive-compulsive inventory(MOCI)를 조사하였다. 두 군간 연속변수 비교에는 독립 t-검정, 비연속비교는 ${\chi}^2$-검정, 두 변수간의 상관관계는 Pearson 상관분석, 그리고 세 군 이상 비교에는 ANOVA를 이용하였다(p<0.05, 양측검정). 결 과 : 평일 수면시간 5시간 36분, 주말 수면시간 7시간 39분으로, 주말 수면시간이 더 길었다(t=15.94, p<0.001). 취침 시각은 평일 0 : 49, 주말 1 : 34으로 주말에 더 늦게 취침하였고(t=-5.23, p<0.001), 기상 시각은 평일 6 : 58,. 주말 9 : 30으로 주말에 더 늦게 기상하였다(t=-24.48, p<0.001). PSQI는 ESS(r=0.383, p<0.001), GASS(r=0.326, p<0.001), CES-D(r=0.393, p<0.001), 그리고 MOCI 점수(r=0.247, p< 0.001)와 양의 상관관계를 보였지만, 성적과는 상관관계를 보이지 않았다(r=0.072, p=0.228). 학년이 높을수록 PSQI, GASS, CES-D, MOCI 점수가 낮았다(p<0.05). 결 론 : 의학전문대학원생들의 수면의 질은 낮았고 수면 시간은 부족하였다. 수면의 질은 주간졸림, 우울감, 스트레스, 강박 성향과 연관성이 있었다.

• 융합정보논문지
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• 제11권5호
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• pp.50-56
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• 2021

본 연구는 임부의 사회적 지지, 임신 스트레스 그리고 불안이 삶의 질에 영향을 미치는 영향요인을 파악하기 위해 시도 되었다. 본 연구는 2개 지역 D 와 S 지역에 거주하는 임부 117명을 대상으로 한 서술적 조사연구이다. 설문 전 연구의 취지와, 목적, 절차에 대하여 설명을 하고 진행하였다. 자료는 SPSS 21.0 을 이용하였고, 빈도분석, 분산분석, t검증, 상관분석, 희귀분석으로 실시하였다. 자료 수집은 2020년 1월부터 2월까지 하였다. 본 연구결과는 일반적 특성에 따른 임부의 삶의 질 차이는 수면시간, 경제수준, 건강상태, 활동량, 임신주기에서 유의미한 차이를 보였다. 삶의 질에 영향을 미치는 변수는 사회적 지지(β= .432, p= .000), 임신 스트레스(β=- .407, p= .000), 불안(β=- .182, p= .010) 순으로 확인되었다. 임부는 임신 스트레스와 불안 등을 경험하는 삶의 질 저하문제로 이어질 수 있어 임부에 대한 건강증진 프로그램 개발을 해야 할 것이며 삶의 질 증진을 위한 적극적인 간호중재 제공에 대한 필요성이 제기된다.

• 한국수산과학회지
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• 제36권1호
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• pp.65-67
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• 2003

Flounder (Paralichthys olivaceus) fish goes through metamorphosis in the larvae phase. In this phase, it secretes much thyroid hormone to control metamorphosis. Sharp change in the environment and nutrition deficiency may cause stress in the metamorphosis phase. It leads to interfering with the development of thyroid hormone and finally inhibits the normal growth of larvae. In this study, the correlation between the change in thyroid hormones and the albinism appearance was examined by growing them with low temperature ($13^{\circ}C$) stress over the premetamorphosis stages (stage $D\~F$) of flounder metamorphosis. Albinism rate was $15\%$ in the low temperature group and $25\%$ in the control goup. $T_{4}\;and\;T_{3}$ of the control group tended to increase from stage F as larvae grew. $T_{4}$ increased 2 times compared to the control group as 72 ng/g at stage H, the increasing phae of water temperature, in the low temperature group. $T_{3}$ increased 8 times compared to the control group as 2.9 ng/g at stage E, the decreasing phase of water temperature. Therefore, it is judged that the albinism appearance of flouner is caused from the sharp increase in $T_{3}$ by the inappropriate secretion of thyroid hormone.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권9호
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• pp.431-437
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• 2002

Low hemolysis is one of the key factors in the production of successful rotary blood pumps. It is, however, difficult to identify the areas where hemolysis occurs. Computational fluid dynamics(CFD) analysis enables the engineer to predict hemolysis on a computer Fluid dynamics in five different axial flow pumps was analyzed 3-dimensionally using CFD software. The impeller was rotated at a speed which supplied a flow of 5L/min at a pressure difference of 100mmHg. Changes in the turbulent kinetic energy along streamlines through the pumps were computed. Reynolds' shear stress( (equation omitted) ) was calculated using the turbulent kinetic energy. Hemolysis was evaluated based on Reynolds'shear stress and its exposure time(t) : dHb/Hb=3.62$\times$10$^{-5}$ $t^{0.785}$$\tau$$^{2.416}$ . Hemolysis of the pumps was measured in vitro using fresh bovine blood to which citrate phosphate dextrose was added to prevent clotting. A pump flow of 5L/min was maintained at a pressure difference of 100mmHg for 3h. The normalized index of hemolysis(NIH) as measured. Reynolds' shear stress was high behind the impellers. The measured NIH and the calculated hemolysis(dHb/Hb) shoed a good correlation; NIH=0.0003(dHb/Hb) (r=0.90, n=6) in the range of NIH between 0.003 and 1.1. CFD analysis can predict the in vitro results of hemolysis as well as the areas where hemolysis occurs.ysis occurs.

• Steel and Composite Structures
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• 제12권3호
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• pp.249-260
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• 2012

In this study, stress and deflection behaviours of T-type welding joint applied to HE200M steel beam and column were investigated in finite element method (FEM) under different distributed loads. In the 3D-FEM modelling, glue option was used to contact between steel materials and weld nuggets. Geometrical model was designed as 3-dimensional solid in ANSYS software program. After that, homogeneous, linear and isotropic properties were used to design to materials of model. Solid-92 having 3-dimensional, 4 faced and 10-noded was selected as element type. In consequence of mesh operation, elements of 13285 and nodes of 28086 were occurred. Load distribution was applied to top surface of steel beam to determine behaviours of stress and deflection. As a result of FEM analysis applied with the loads of 55,000 N, 110,000 N and 220,000 N, maximum values were obtained as 116 N/$mm^2$, 232 N/$mm^2$ and 465 N/$mm^2$ for stress and obtainedas 1,083 mm, 2,166 mm and 4.332 mm for deflection, respectively. When modelling results and classical calculation values were compared, it was obtained difference of 10 % for stress values and 2.5% for deflection values.

• Interaction and multiscale mechanics
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• 제4권2호
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• pp.85-105
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• 2011

The influence of surface elasticity and surface residual stress on the elastic field of an isotropic nanoscale elastic layer of finite thickness bonded to a rigid material base is considered by employing the Gurtin-Murdoch continuum theory of elastic material surfaces. The fundamental solutions corresponding to buried vertical and horizontal line loads are obtained by using Fourier integral transform techniques. Selected numerical results are presented for the cases of a finite elastic layer and a semi-infinite elastic medium to portray the influence of surface elasticity and residual surface stress on the bulk stress field. It is found that the bulk stress field depends significantly on both surface elastic constants and residual surface stress. The consideration of out-of-plane terms of the surface stress yields significantly different solutions compared to previous studies. The solutions presented in this study can be used to examine a variety of practical problems involving nanoscale/soft material systems and to develop boundary integral equations methods for such systems.

• Food Science and Biotechnology
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• 제18권1호
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• pp.162-166
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• 2009

This study evaluated glucose effect on Listeria monocytogenes survival under gamma irradiation and NaCl stress. L. monocytogenes in phosphate buffered saline (PBS) plus glucose (0-4%) was treated with gamma irradiation (0-0.5 kGy), and the samples were then exposed to NaCl (0-9%) in tryptic soy agar plus 0.6% yeast extract. $D_{10}$ and $t_{3D}$ values were determined, and a model for prediction of $D_{10}$ values was developed. Cell counts of L. monocytogenes reduced as irradiation dose increased, and L. monocytogenes in PBS (no glucose) was more sensitive to irradiation and NaCl compared to those in PBS (2 or 4% glucose). $D_{10}$ values were 0.07-0.1, 0.12-0.16, and 0.13-0.15 kGy for 0, 2, and 4% glucose, respectively. The $t_{3D}$ values were 0.22-0.3 (0% glucose), 0.35-0.48 (2% glucose), and 0.40-0.44 (4% glucose). A model performance was acceptable. These results indicate that glucose in foods would increase the resistance of L. monocytogenes to gamma irradiation and NaCl stress.

• The Korean Journal of Physiology and Pharmacology
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• 제13권2호
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• pp.85-89
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• 2009

Puerariae flos (PF) is a traditional oriental medicinal plant and has clinically been prescribed for a long time. The purpose of the present study was to examine the effect of PF on repeated stress-induced alterations of learning and memory on a Morris water maze (MWM) test in ovariectomized (OVX) female rats. The changes in the reactivity of the cholinergic system were assessed by measuring the immunoreactive neurons of choline acetyltransferase (ChAT) in the hippocampus after behavioral testing. The female rats were randomly divided into four groups: the nonoperated and nonstressed group (normal), the sham-operated and stressed group (control), the ovariectomized and stressed group (OS), and the ovariectomized, stressed and PF treated group (OSF). Rats were exposed to immobilization stress (IMO) for 14 d (2 h/d), and PF (400 mg/kg, p.o.) was administered 30 min before IMO stress. Results showed that treatments with PF caused significant reversals of the stress-induced deficits in learning and memory on a spatial memory task, and also increased the ChA T immunoreactivities. In conclusion, administration of PF improved spatial learning and memory in OVX rats, and PF may be useful for the treatment of postmenopausal-related dementia.

• Journal of Microbiology
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• 제44권4호
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• pp.369-374
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• 2006

To investigate the mechanism of salt tolerance of gram-positive moderately halophilic bacteria, two-dimensional gel electrophoresis (2-D PAGE) was employed to achieve high resolution maps of proteins of Halobacillus dabanensis $D-8^T$. Approximately 700 spots of proteins were identified from these 2-D PAGE maps. The majority of these proteins had molecular weights between 17.5 and 66 kDa, and most of them were distributed between the isoelectric points (pI) 4.0 and 5.9. Some protein spots were distributed in the more acidic region of the 2-D gel (pI <4.0). This pattern indicated that a number of proteins in the strain $D-8^T$ are acidic. To understand the adaptation mechanisms of moderately halophilic bacteria in response to sudden environmental changes, differential protein profiles of this strain were investigated by 2-D PAGE and $Imagemaster^{TM}$ 2D Platinum software after the cells were subjected to salt shock of 1 to 25% salinity for 5 and 50 min. Analysis showed 59 proteins with an altered level of expression as the result of the exposure to salt shock. Eighteen proteins had increased expression, S proteins were induced, and the expression of 33 proteins was down-regulated. Eight of the up-regulated proteins were identified using MALDI-TOF/MS and MASCOT, and were similar to proteins involved in signal transduction, proteins participating in energy metabolism pathways and proteins involved in stress.

• Animal Bioscience
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• 제36권4호
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• pp.601-608
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• 2023

Objective: This study was conducted to investigate the effects of energy and protein levels in the diet of Hanwoo heifers on growth response and animal behavior. Methods: Forty heifers were randomly allocated into three experimental groups according to the target daily weight gain in 8 pens (T-0.2, 2 replications; T-0.4 and -0.6, 3 replications) based on similar body weight (BW) and age in months. The target average daily gain (ADG) was set at 0.2 (T-0.2), 0.4 (T-0.4), and 0.6 kg/d (T-0.6), and feed was based on National Institute of Animal Science (NIAS, 2017). In order to minimize hunger stress of T-0.2 and -0.4, the feeding ratio of rice straw was set to 55%, 50%, and 45% for T-0.2, -0.4 and T-0.6, respectively, so that the dry matter (DM) intake for all treatment groups was uniform but the energy and protein levels in the diet were adjusted differently. A total of 6 items (lying, standing, eating, rumination, walking and drinking) of animal behavior were analyzed. Results: During the whole period of the experiment, the ADG of the T-0.2, -0.4 and -0.6 treatments were 0.48, 0.56, and 0.65 kg/d (p<0.05), respectively, showing higher gain than the predicted value, especially for the low target ADG group. Based on these results, regression equations for the total digestible nutrient (TDN) and crude protein (CP) requirements were derived. No behavioral differences were found according to the energy and protein levels in the diet because the DM intake was kept constant by adjusting the roughage and concentration ratio. However, eating time was longer (p<0.05) at T-0.2 than T-0.6 during the whole day. Conclusion: Through this study, it was possible to derive regression equations for predicting TDN and CP requirements according to the target ADG and BW.