• Dementia and Neurocognitive Disorders
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• v.21 no.4
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• pp.147-161
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• 2022

Background and Purpose: Subjective cognitive decline (SCD) refers to the self-perception of cognitive decline with normal performance on objective neuropsychological tests. SCD, which is the first help-seeking stage and the last stage before the clinical disease stage, can be considered to be the most appropriate time for prevention and treatment. This study aimed to compare characteristics between the amyloid positive and amyloid negative groups of SCD patients. Methods: A cohort study to identify predictors for the clinical progression to mild cognitive impairment (MCI) or dementia from subjective cognitive decline (CoSCo) study is a multicenter, prospective observational study conducted in the Republic of Korea. In total, 120 people aged 60 years or above who presented with a complaint of persistent cognitive decline were selected, and various risk factors were measured among these participants. Continuous variables were analyzed using the Wilcoxon rank-sum test, and categorical variables were analyzed using the χ² test or Fisher's exact test. Logistic regression models were used to assess the predictors of amyloid positivity. Results: The multivariate logistic regression model indicated that amyloid positivity on PET was related to a lack of hypertension, atrophy of the left temporal lateral and entorhinal cortex, low body mass index, low waist circumference, less body and visceral fat, fast gait speed, and the presence of the apolipoprotein E ε4 allele in amnestic SCD patients. Conclusions: The CoSCo study is still in progress, and the authors aim to identify the risk factors that are related to the progression of MCI or dementia in amnestic SCD patients through a two-year follow-up longitudinal study.

• Korean Journal of Plant Resources
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• v.37 no.4
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• pp.314-320
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• 2024

To speed up the extract of endoparasitic nematodes from roots, four extraction methods with or without root-grinding were compared; 1) immersion, 2) immersion + Air, 3) Oostenbrink dish, and 4) Mistifier. The experiments were conducted for nine days by using perilla roots infested with Pratylenchus vulnus. Root-lesion nematodes continuously extracted from perilla roots during the experiments and as much as 3-10% in 9^th days. The total number of nematodes extracted from 2 g of perilla root in nine days were varied among methods (379-1,824 nematodes); the most nematodes were extracted by root grinding + immersion + air (1,824) and the root-grinding + mistifier method (1,349) (p = 0.05). In the first two days of extraction, root-grinding + mistifier extracted the most nematodes (725 nematodes), followed by root-grinding + immersion + Air (555 nematodes), and root-grinding + Oostenbrink dish (421 nematodes). Root-grinding effected as much as 16-108% more nematodes extraction when compared to without root-grinding (p = 0.01).

• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3835-3850
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• 2024

The high-temperature gas-cooled reactor (HTGR) with spherical fuel elements contains complex pebble flow. The flow behavior of pebbles is influenced by various factors, such as pebble density, friction coefficient, wall structure, and discharge port size. Using a GPU-DEM numerical model, the effects of the friction coefficient on the cyclic loading and unloading of pebbles in the full-scale HTR-PM are studied. Numerical simulations with up to 420,000 spherical pebbles are conducted. Four sets of friction coefficient values are determined for comparative analysis based on experimental measurements. Discharging speed, residence time, stress, porosity, and velocity distribution are quantitatively analyzed. In addition, a comparison with the CT-PFD experiment is carried out to validate the numerical model. The results show that near-wall retention phenomena are observed in the reactor core only when using large friction coefficients. However, using friction coefficient values closer to the measured experimental values, the pebble bed in HTR-PM exhibited good flow characteristics. Furthermore, the friction coefficient also influences the porosity and velocity distribution of the pebble bed, with lower friction coefficients resulting in lower overall stress in the bed. The discharge outlet's influence varies with different friction coefficient values. In summary, this study demonstrates that the value of the friction coefficient has a complex influence on the pebble flow in HTR-PM, which provides important insights for future numerical and experimental studies in this field.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.1
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• pp.1-12
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• 2013

Acoustic backscatter profiles were measured by Eco-sounder along an east-west section in the mid-eastern Yellow Sea and at an anchoring station in the low salinity region off the Keum River estuary in September 2012, with observing physical water property structure by CTD. Tidal front was established around the sand ridge developed in 50 m depth region. Internal waves measured by Eco-sounder during low tide period in the eastern side of the sand ridge were nonlinear depression waves with wave height of 15 m and mean wavelength of 500 m. These waves were interpreted into tidal internal waves that were produced by tidal current flowing over the sand ridge to the southeast. When weakly non-linear soliton model was applied, propagation speed and period of these internal depression wave were 50 m/s and 16~18 min. Red tides by Dinoflagelates Cochlodinium were observed in the sea surface where strong acoustic scattering layer was raised up to 7 m. Hourly CTD profiles taken at the anchoring station off the Keum River estuary showed the halocline depth change by tidal current and land-sea breeze. When tidal current flowed strongly to the northeast during flood period and land-breeze of 7 m/s blew to the west, the halocline was temporally raised up as much as 2 m and acoustic profile images showed a complex structure in the surface layer within 5-m depth: in tens of seconds the declined acoustic structure of strong and weak scattering signals alternatively appeared with entrainment and intrusion shape. These acoustic profile structures in the surface mixed layer were observed for the first time in the coastal sea of the mid-eastern Yellow Sea. The acoustic profile images and turbidity data suggest that relatively transparent low-layer water be intruded or entrained into the turbid upper-layer water by vertical shear between flood current and land breeze-induced surface current.

• The Journal of Industrial Distribution & Business
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• v.2 no.2
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• pp.39-45
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• 2011

The Korean distribution industry is gearing up for an endless competition. Greeting low growth era, less competitive parties will be challanged seriously for their survival. But for large discount stores, they have shown steady annual growth for years. However, because of the saturation for numbers of stores, the difficulty of gaining new sites, and the changes in the consumer's consumption behavior caused by the recession, now they are seeking for a new customers-based business formats. Accordingly, a large corporate comopanies made supermarkets which are belonged to affiliated companies of large corporate comopanies. They based on the strong buying power, focused on SSM(Super Super Market) ave been aggressively develop nationwide multi-stores. The point is that these stores are threatening at small and medium-sized, community-based private supermarkets. Private supermarkets and retailers, who are using existing old operation systems and their dilapidated facilities, are losing a competitive edge in business. Recent the social effects of large series of corporate supermarkets for traditional markets has been very controversial, and commercial media, academia, and industry associated with it have been held many seminars and public hearings. This may slow down the speed in accordance with the regulations, but will not be the crucial alternative. The reason for this recent surge of enterprise-class SSM up, one of the reasons is a stagnation in their offline discount mart, so they are finding new growth areas. Already in the form of large supermarkets across the country got most of the geographical centre point and is saturated with stages. Targeting small businesses that do not cover discount Mart, in order to expand business in the form of SSM is urgent. By contrast, private supermarkets are going to lose their competitiveness. The vulnerability of individual supermarkets, one of the vulnerabilities is price which economies of scale can not be realized so they are purchasing a small amount of products and difficult to get a quantity discount. The lack of organization and collaboration, and education which is not practical, caused the absencer of service-oriented situations. As a first solution, making specialty shops which are handling agricultures, fruits and vegetables and manufactured goods is recommended. Second, private supermarkets franchisees join the organization for the organization and collaboration is recomaned. It can be meet the scale of economy and can be formed a alternative business formats to a government. Third, the education is needed as a good service will get consumer's awareness. In addition, a psychological stores operating is also one way to stimulate consumer sentiment as SSM can't operate. Japan already has a better conditions of their lives through small chain expression. This study includes the vulnerabilities of private supermarkets, and suggests a competitiveness reinforcement strategies.

• Korean Journal of Remote Sensing
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• v.33 no.5_3
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• pp.821-834
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• 2017

The increase in the rate of industrialization due to urbanization has caused the Urban Heat Island phenomenon where the temperature of the city is higher than the surrounding area, and its intensity is increasing with climate change. Among the cities where heat island phenomenon occurs, Seoul city has different degree of urbanization, green area ratio, energy consumption, and population density in each administrative district, and as a result, the strength of heat island is also different. So It is necessary to analyze the difference of Urban Heat Island Intensity by administrative district and the cause. In this study, the UHI intensity of the administrative gu and the administrative dong were extracted from the Seoul metropolitan area and the differences among the administrative districts were examined. and linear regression analysis were conducted with The variables included in the three categories(weather condition, anthropogenic heat generation, and land use characteristics) to investigate the cause of the difference in heat UHI intensity in each administrative district. As a result of analysis, UHI Intensity was found to be different according to the characteristics of administrative gu, administrative dong, and surrounding environment. The difference in administrative dong was larger than gu unit, and the UHI Intensity of gu and the UHI Intensity distribution of dongs belonging to the gu were also different. Linear regression analysis showed that there was a difference in heat island development intensity according to the average wind speed, development degree, Soil Adjusted Vegetation Index (SAVI), Normalized Difference Built-up Index (NDBI) value. Among them, the SAVI and NDBI showed a difference in value up to the dong unit and The creation of a wind route environment for the mitigation of the heat island phenomenon is necessary for the administrative dong unit level. Therefore, it is considered that projects for mitigating heat island phenomenon such as land cover improvement plan, wind route improvement plan, and green wall surface plan for development area need to consider administrative dongs belonging to the gu rather than just considering the difference of administrative gu units. The results of this study are expected to provide the directions for urban thermal environment design and policy development in the future by deriving the necessity of analysis unit and the factors to be considered for the administrative city unit to mitigate the urban heat island phenomenon.

• Archives of design research
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• v.1 no.1
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• pp.1-162
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• 1980

The Design Society of Korea. It is our urgent task that we should map out our detailed guiedlines for the improvement of export-oriented industries and of the design of export goods in preparation for our export goal of $30 billion in the upcoming 1980s. The government, university design researchers, and most entrepreneurs have confronted diverse kinds of racking issues: how much do most export industries take advantage of the indus-trial design for the improvement of the quality of export goods\ulcorner, structural defects of most export industries, chronic and vicious cycle of overlooking the value of the industrial design in the process of manufacturing export goods and etc. In other words, the recent trend of slighting the industrial design is to speed up the sales of only unsophisticated goods on the international markets. Although Koreans have been plagued by scantiness of natural resources under these circumstances, most Korean people have showed off their strong will for today's growth. Furthermore, most exporters should do their best to sweep overseas markets by manufacturing sophisticated goods outranking those commodi-ties made by the United States, Japan, West Germany and the other developed countries. In this respect, we have to make our best efforts for the expensive application and practical use of the industrial design, one of the comprehensive sciences, in the face of the hard realities and conditions which we have confronted until now. For example, it can be attributed to the practical application of the industrial design that the neighboring Japan, West Germany, France, the United Kingdom in Europe, and the United States in North America have formulated a highly advan-ced cultural zone and braced up for their own trade protection-ism and tightened their embargoes on EEC goods. Unless any export goods take the best advantage of the industrial design, one of the behavioral sciences capable of satisfying the material mental needs of modern men and of promoting cultural growth, I am convinced that they will not infiltrate into any countries that have enjoyed their own highly cultural lives. It is absolutely important that most Korean universities, state-run, private corporations and research institutes should work out the improvement strategy for the development and practical use of the industrial design as will as the revision of the present curricula of the departments of design. However, most design researchers have come to grips with several difficult problems such as the correlation of export oriented industries and the industrial design and the development of the design of export goods. The improvement of the industrial design is our urgent assignment that we have to solve in the 1980s. Accordimgly, I cannot too much emphasize the value the recognition of the industrial design in our industrial communities because we have never witnessed the prosperity of those countries which have taken little notice of the importance of the industrial design. Hopefully, most entrepreneurs will take much consideration of the value of the industrial design and then can defeat their rival businessmen on the international markets by exporting goods of highly sophisticated design. In this respect, the main purpose of the research paper which this society presented is to underline the fact that the improvement and development of the industrial design is our common assignment to be studied from the viewpoints of national dimension as well as in conformity with our immediate goal for the export-oriented prosperity of state. In conclusion, I would like to highlight the fact that our export goods shall be continually developed in pace with the correlative improvement of the indudtrial design so as to pave the way for their bright prospect and to enhance their best impression of the first-class goods on the international markets.

• Journal of Life Science
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• v.21 no.3
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• pp.435-443
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• 2011

The purpose of this study is to identify the effects of exercise training [ET, 10~18 m/min (speed), 20~30 min (exercise duration)/a day for 5 day/wk, 6 wk) on PGC-$1{\alpha}$, GLUT-1, Tfam, Cu,Zn-SOD and Mn-SOD proteins in brain of STZ-induced diabetic rats. The male Sprague-Dawley (SD) rats were single-injected intraperitoneally with 50mg/kg of streptozotocin (STZ) to produce STZ-induced diabetic rats. Rats were divided into 3 experimental groups with 8 rats in each group, as follows: (1) non-STZ group (n=8), (2) STZ-CON group (n=8), (3) STZ-EXE group (n=8). The results of this study suggest that i) serum glucose level was significantly reduced in STZ-EXE group compared with STZ-CON group (p<0.05), ii) PGC-$1{\alpha}$ (p<0.001), mtPGC-$1{\alpha}$ (p<0.001), GLUT-1 (p<0.001), and mtTfam (p<0.001) proteins in brain of STZ-induced diabetic rats were significantly increased in STZ-EXE group compared with STZ-CON group, iii) Cu,Zn-SOD (p<0.001) and Mn-SOD (p<0.01) proteins in the STZ-induced diabetic rats were significantly increased in STZ-EXE group compared with STZ-CON group. In conclusion, the findings of the present study reveal that treadmill exercise training increases brain GLUT-1 protein level possibly through up-regulation of PGC-$1{\alpha}$ and Tfam proteins which represent key regulatory components of stimulation of brain mitochondrial biogenesis. In addition, treadmill exercise training may prevent oxidative stress by up-regulation of Cu,Zn-SOD and Mn-SOD proteins in the STZ-induced diabetic rats.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.5 no.1
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• pp.125-141
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• 1998

The purpose of this research is to analyze the effects of aerobic exercise on body composition, cardiopulmonary function, serum lipid level and antioxidants of obese and normal college female students. The subject group was made up of 13 normal students (below 30% body fat ratio) and 12 obese students (above 30% body fat ratio). After a pretest, the subjects were given an 8-week aerobic program. Then the subjects were given a posttest and analyzed of body composition, serum lipid level, antioxidants and cardiopulmonary function after the 6th and the 8th week of the program. The program schedule was made up of 4 days per week, 60 minutes per day. Test includes B.W., subscapular and triceps subcutaneous fat thickness, change of respiratory gas, and two blood sampling before treadmill exercise and post all out state, which analyzed serum lipid and antioxidants. The subjects performed treadmill exercise starting with 4km/hr of walking and then gradually increase the speed of 1km/hr per minute until all out state. The obtained data were analyzed using SAS program. The statistical methods employed here were one-way ANOVA with repeated measure, Duncan Multiple range test, paired-t test and t-test. The test results and conclusion of this research were as follows. 1. The effects of aerobic exercise on body composition were as follows ; Percent body fat was significantly reduced 6 weeks after the program and lean body mass was significantly increased 8 weeks after the program in both groups(obese group: F=3.44 P=.044, normal group: F=3.30 P=.048). subscapular skinfold of the obese group showed a remarkable decrease after the 6th week(F=4.33 P=.021) triceps skinfold of the normal group showed a remarkable decrease after the 6th and the 8th week(F=4.55 P=.017) compared with readings before the aerobic program, the aerobic program made a bigger difference concerning body fat, lean body mass, subscapular skinfold in the obese group than in the normal group(t=2.41 P=.024, t=2.40 p=.025, t=2.43 p=.028). 2. The effects of aerobic exercise on cardiopulmonary function were as follows ; Maximal $O_2$ uptake/kg was significantly increased 6 weeks after the program in the obese group(F=3.20 P=.054), but not much difference was observed in the normal group. Maximal pulse rate was significantly reduced in both groups after 6 weeks of the program(obese group: F=2.77 P=.087, normal group: F=7.17 P=.001). 3. The effects of aerobic exercise on serum lipid level were as follows ; In a resting period, total cholesterol, Triglyceride, and LDL-cholesterol were slightly higher in the obese group than in the normal group, but HDL-cholesterol was higher in the normal group. But, with the aerobic program, total-cholesterol, Triglyceride, LDL-cholesterol were reduced gradually and HDL-choleterol got increased in both groups, but not much change was noticed in the normal group. However, in the obese group, serum HDL-cholesterol level got increased significantly(F=5.12 P=.012). 4. The effects of aerobic exercise in serum antioxidants were as follows ; In a resting period, the obese group's serum Free Radical and GSSG content were higher than the normal group's and the normal group's serum GSH content was higher than the obese group's. After 6 weeks of the aerobic program, Free Radical was reduced significantly in both groups(obese group: F=13.87 P=.000, normal group: F=18.60 P=.000) In the obese group, 8 weeks after the program, GSH was increased significantly(F=13.78, P=.000). In the normal group, 6 weeks after the program, GSH was reduced but increased again after 8 weeks(F=6.07 P=.005). Plasma GSSG was significantly increased after 8 weeks of exercise in both groups(obese group: F=19.75 P=.000, normal group: F=22.42 P=.000,) Compared with readings before the aerobic program, the aerobic program made a bigger difference serum GSH in the normal group than in the obese group(t=3.37 p=.003). As this result shows, it is known that the regular aerobic exercise improves cardiopulmonary function, body composition, serum lipid effectively and through the serum Free Radical reduction and antioxidant system activation, oxidant stress was suppressed. This effect was higher in the obese group than in the normal one. At least 6weeks exercise period need for improvement of body composition, cardiopulmonary function and activation of antioxidant system. This result suggest that improvement of serum lipid profile was needed longer than 8weeks exercise period.

• Journal of Chest Surgery
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• v.32 no.3
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• pp.255-261
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• 1999

Background: Atrial fibrillation is one of the most prevalent of all arrhythmias and in up to 79% of the patients with mitral valve disease. This study examined whether the atrial fibrillation that occur in patients with mitral valve operation could be eliminated by a concommitant maze operation without cryoablation. Material and Method: From May 1997 to April 1998, 14 patients with atrial fibrillation associated with mitral valve disease underwent Maze III operation without cryoablation. Preoperatively there were 6 men and 8 women with an average age of 46.2${\pm}$10.7 years. Eleven patients had mitral stenosis, and three had mitral insufficiency. The associated heart diseases were aortic valve disease in 4, tricuspid valve regurgitation in 1 and ASD in 2. Using transthoracic echocardiography, the mean left atrial diameters was 54.7${\pm}$5.3 mm and thrombi were found in the left atrium of 2 patients. Postoperatively the ratio between the peak speed of the early filling wave and that of the atrial contraction wave (A/E ratio) was determined from transmitral flow measurement. Operations were mitral valve replacement in 13 including 4 aortic valve replacements, 1 DeVega annuloplasty and 2 ASD closures. Maze III operation was performed in 1 patient. Result: Five patients (38%) had recurred atrial fibrillation, which was reversed with flecainide or amiodarone at the average time of postoperative 38.8${\pm}$23.5 days. Postoperative complications were postoperative transient junctional rhythm in 6, transient atrial fibrillation in 5, reoperation for bleeding in 3, postpericardiotomy syndrome(1), unilateral vocal cord palsy(1), postoperative psychosis(1), and myocardial infarction(1). Postoperatively A/E ratio was 0.43${\pm}$0.22 and A wave found in 9(64%) patients. 3 to 14 months postoperatively (average follow- up, 8.1 months), all of patients had normal sinus rhythm and 9(64%) patients had left atrial contraction and 11(79%) patients were not on a regimen of antiarrhythmic medication. Conclusion: We conclude that Maze III operation without cryoablation is an effective surgical treatment in atrial fibrillation associated with the mitral valve disease.