• 대기
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• 제25권3호
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• pp.501-510
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• 2015

In this study, the characteristics of flows around building groups are investigated using a computational fluid dynamics (CFD) model. For this, building groups with different volumetric ratios in a fixed area are considered. As the volumetric ratio of the building group increases, the region affected by the building group is widened. However, the wind-speed reduced area rather decreases with the volumetric ratio near the ground bottom (z ${\lesssim}$ 0.7H, here, H is the height of the building group) and, above 0.7H, it increases. As the volumetric ratio decreases (that is, space between buildings was widened), the size of recirculation region decreases but flow recovery is delayed, resulting in the wider wind-speed reduced area. The increase in the volumetric ratio results in larger drag force on the flow above the roof level, consequently reducing wind speed above the roof level. However, above z ${\gtrsim}$ 1.7H, wind speed increases with the volumetric ratio for satisfying mass conservation, resultantly increasing turbulent kinetic energy there. Inside the building groups, wind speed decreased with the volumetric ratio and averaged wind speed is parameterized in terms of the volumetric ratio and background flow speed. The parameterization method is applied to producing averaged wind speed for 80 urban areas in 7 cities in Korea, showing relatively good performance.

• Restorative Dentistry and Endodontics
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• 제45권1호
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• pp.10.1-10.8
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• 2020

Objectives: This study aimed to compare the shear bond strength (SBS) of a self-adhering flowable composite (Dyad Flow) and a bulk-fill flowable composite (Smart Dentin Replacement [SDR]) to several pulp-capping materials, including MTA Plus, Dycal, Biodentine, and TheraCal. Materials and Methods: Eighty acrylic blocks with 2-mm-deep central holes that were 4 mm in diameter were prepared and divided into 2 groups (n = 40 each) according to the composite used (Dyad Flow or SDR). They were further divided into 4 sub-groups (n = 10 each) according to the pulp-capping agent used. SBS was tested using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed using 2-way analysis of variance. A p value of < 0.05 was considered to indicate statistical significance. Results: A statistically significant difference (p = 0.040) was found between Dyad Flow and SDR in terms of bond strength to MTA Plus, Dycal, Biodentine, and TheraCal. Conclusions: Among the 8 sub-groups, the combination of TheraCal and SDR exhibited the highest SBS.

• The Journal of Korean Physical Therapy
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• 제30권2호
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• pp.41-46
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• 2018

Purpose: This study examined the effects of knee extension exercise using blood flow restriction on the changes in the thickness and static balance ability of the tendon of the rectus femoris muscle and achilles tendon. Methods: A total of 30 subjects was were divided into two groups of 15 subjects each. The changes in the thickness and balance of their tendons were measured by ultrasonography and balance equipment. The measurements were taken three times: before the experiment, 4 weeks after, and 8 weeks after. The results were analyzed by repeated measure ANOVA, one-way ANOVA was conducted in cases where there were time-to-group interactions in the intra-individual effects test. Results: Significant differences in the thickness of the tendon of the rectus femoris muscle and Achilles tendon were found between the groups, over time, and in the time-to-group interactions (p<0.05). The changes in balance in both feet when the supporting positions between eye-open and eye-closed states were significantly different in the time-to-group interactions (p<0.05), but were not different between the groups (p>0.05). Conclusion: Knee extension exercise using blood flow restriction leads to significant differences in the increase in tendon thickness and changes in balance, indicating that the results of this study can be utilized as basic data for future studies and for rehabilitation treatment at clinics.

• The Journal of Korean Physical Therapy
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• 제17권2호
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• pp.88-106
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• 2005

AMF(amplitude modulated frequency) is defined as currents in the frequency range 1 to 100Hz. The aim of this study was to determine the effects of blood flow and skin temperature according to different stimulating frequency($1{\sim}30Hz,\;30{\sim}50Hz,\;50{\sim}100Hz$) of interferential currents. The results were as follow; 1. There were statistical significance on the blood flow with IFC 1, IFC 2, and IFC 3 group, and inter-groups(p<0.05). 2. There were statistical significance on the skin temperature with IFC 1 and IFC 3 group, and inter-groups(p<0.05). 3. IFC 1 was more statistical significance than IFC 3 group on blood flow(pP<0.05) 4. There was no statistical significance between IFC 1 and IFC 3 group on skin temperature(p>0.05).

• 한국엔터테인먼트산업학회논문지
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• 제14권4호
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• pp.333-340
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• 2020

본 연구는 하지혈류제한벨트를 한 그룹과 하지 않은 그룹의 균형과 순발력의 변화를 알아보기 위해 광주 지역에 소재한 K대학교 학생 40명을 선정하여 실험군 20명과 대조군 20명을 무작위 배치하여 2019년 9월 16일부터 10월 11일까지 4주간 스쿼트 운동을 실시하였다. 스쿼트 운동 시 혈류제한은 BFR band를 착용하였고 편안하게 선 상태에서 120 mmHg 압력을 넣어 하지혈류제한을 하였다. 실험 결과 앞·중간·뒷부위 발바닥 압력의 시간에 따른 변화에서 두 그룹 모두 통계학적으로 유의한 차이가 나타나지 않았고(p>.05), 실험군과 대조군 간 상호작용 차이도 없었다(p>.05). Height, Maximum Concentric Power, Take Off Speed에서 시간에 따른 유의한 차이를 확인할 수 있었다(p<.05). 이와 같은 결과로 보아 낮은 강도 운동을 통해서도 하지혈류제한을 통해 큰 효과를 얻을 수 있을 것으로 사료된다. 본 논문은 혈류제한운동이 순발력과 균형에 미치는 영향을 알아보고자 하였으며 향후 하지혈류제한 운동을 통해 낮은 강도의 운동으로도 큰 운동 효과를 얻을 수 있는 것의 기초자료로 활용될 수 있을 것이다.

• 대한한방내과학회지
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• 제29권1호
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• pp.258-264
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• 2008

Objectives : The aim of this study was to confirm the characteristics of oral malodor patients by evaluating the differences of salivary flow rate, secretory immunoglobulin A (sIgA) level in saliva between the patient and control groups, and the correlation with the tongue coating, volatile sulfur compound (VSC), salivary flow rate and sIgA level in saliva in the patients group. Methods : Forty-seven patients with oral malodor and twenty healthy volunteers were included in this study. Their tongue coating was assessed with the Winkel tongue coating index, and salivary flow rate, sIgA concentrations in saliva and the level of VSC in oral cavity were measured. Results : There were no significant differences of the salivary flow rate and the sIgA level in saliva between the patient and control groups, but there was a significant relationship between the accumulation of tongue coating and the level of VSC in oral cavity. Conclusions : Our results suggest that tongue coating is closely related to oral malodor, but further studies are needed to confirm the relationship between tongue coating and sIgA level in saliva.

• Journal of Ginseng Research
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• 제33권4호
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• pp.268-277
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• 2009

Ginsenosides are among the most well-known traditional herbal medicines frequently used for the treatment of cardiovascular symptoms in South Korea. The anti-ischemic effects of compound K (CK), a metabolite of ginsenoside Rb1, on ischemia-induced isolated rat hearts were investigated through the analyses of the changes in the hemodynamics (blood pressure, aortic flow, coronary flow, and cardiac output) and the measurement of the infarct region. The subjects in this study were divided into four groups: the normal control, the CK-alone group, the ischemia-induced group without any treatment, and the ischemia-induced group treated with CK. No significant differences in perfusion pressure, aortic flow, coronary flow, and cardiac output were found between the groups before ischemia was induced. The oxygen and buffer supply was stopped for 30 min to induce ischemia 60 min after reperfusion in the isolated rat hearts, and the CK was administered 5 min before ischemia induction. The CK treatment significantly prevented decreases in perfusion pressure, aortic flow, coronary flow, and cardiac output under ischemic conditions. In addition, the hemodynamics (except for the heart rate) of the group treated with CK significantly recovered 60 min after reperfusion, unlike in the control group. CK significantly limited the infarct. These results suggest that CK treatment has distinct anti-ischemic effects in an exvivo model of an ischemia-reperfusion-induced rat heart.

• 대한수학회논문집
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• 제13권1호
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• pp.123-129
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• 1998

In this paper, we study some dynamical properties of a weakly almost periodic flow. In particular we get, in a weakly almost periodic flow (X,T), the groups I and A(I) of all automorphisms of I are isomorphic, where E(X) is the enveloping semigroup of (X,T) and I is the minimal right ideal in E(X).

• The Journal of Asian Finance, Economics and Business
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• 제7권11호
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• pp.177-184
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• 2020

This paper analyzes factors affecting corporate investment decisions in economic groups listed on the Vietnam stock market. The panel data of the research sample includes 39 economic groups listed on the Vietnam stock market from 2009 to 2019. The Generalized Least Square (GLS) is employed to address econometric issues and to improve the accuracy of the regression coefficients. In this research, the investment rate is a dependent variable. Cash-flow (CF), Investment opportunities (ROA), Fixed capital intensity (FCI), Leverage (LEV), Sales growth (GR), Size (SZ), Business risk (RISK) are independent variables in the study. The model results show that cash flow and sales growth have the same impact on investment decisions of economic groups in Vietnam. In addition, investment opportunities have a negative impact on the capital investment decisions of economic groups. The remaining factors include fixed capital intensity, leverage, firm size, and business risks that have a weak and insignificant impact on capital investment decisions of economic groups in Vietnam. The findings of this article are useful for business administrators, and helping business managers make the right financial decisions. Besides, the research results are also meaningful to money management agencies. The authors recommend that the State Bank of Vietnam should maintain a sustainable monetary policy.

• 대한한방내과학회지
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• 제35권1호
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• pp.24-36
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• 2014

Objectives : This study was performed to evaluate the effects of moxibustion on cerebral blood flow, peripheral blood flow and blood pressure. Methods : We designed a randomized, cross-over study that included 20 healthy, male volunteers who were randomly assigned to one of two groups (the moxibustion group or the control group). The initial trial was followed by a washout period of one week before the groups were switched and the trial repeated. The cerebral blood flow and peripheral blood flow of the volunteers in both groups were measured by mean velocity (Vm), peak systolic velocity (Vs), pulsatility index (PI), perfusion units (PU) and mean blood pressure (BP) before the intervention (baseline), 30 minutes after the intervention, and again 60 minutes after the intervention. Results : 1. The Vm increased significantly in the moxibustion group. The Vs also constantly increased in moxibustion group, but there was no significant difference. 2. The PI decreased significantly in the control group at 0-30 minutes and in the moxibustion group at 30-60 minutes. 3. The PU constantly decreased in moxibustion group. In control group, the PU decreased at 30 minutes and increased slightly at 60 minutes. 4. The mean blood pressure did not show any significant difference between the two groups. Conclusions : This study shows that moxibustion at CV12 increased the cerebral blood flow. Based on this result, we can suggest that moxibustion at CV12 might be helpful in improving the functional recovery of stroke patients. However, further research needs to be conducted on a larger numbers of subjects in order to confirm these effects.