• International Journal of Heart Failure
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• v.6 no.2
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• pp.56-69
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• 2024

Background and Objectives: The number of people with heart failure (HF) is increasing worldwide, and the social burden is increasing as HF has high mortality and morbidity. We aimed to provide updated trends on the epidemiology of HF in Korea to shape future social measures against HF. Methods: We used the National Health Information Database of the National Health Insurance Service to determine the prevalence, incidence, hospitalization rate, mortality rate, comorbidities, in-hospital mortality, and healthcare cost of patients with HF from 2002 to 2020 in Korea. Results: The prevalence of HF in the total Korean population rose from 0.77% in 2002 to 2.58% (1,326,886 people) in 2020. Although the age-standardized incidence of HF decreased over the past 18 years, the age-standardized prevalence increased. In 2020, the hospitalization rate for any cause in patients with HF was 1,166 per 100,000 persons, with a steady increase from 2002. In 2002, the HF mortality was 3.0 per 100,000 persons, which rose to 15.6 per 100,000 persons in 2020. While hospitalization rates and in-hospital mortality for patients with HF increased, the mortality rate for patients with HF did not (5.8% in 2020), and the one-year survival rate from the first diagnosis of HF improved. The total healthcare costs for patients with HF were approximately $2.4 billion in 2020, a 16-fold increase over the $0.15 billion in 2002. Conclusions: The study's results underscore the growing socioeconomic burden of HF in Korea, driven by an aging population and increasing HF prevalence.

• The Korean Journal of Quaternary Research
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• v.31 no.2
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• pp.13-22
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• 2017

The age of the Sorori old fluvial deposits is assumed as old as Last Interglacial(MIS 5) when appying the thalassostatic terrace formation in mid- to downstream Keum river basin, while the young fluvial deposits are interpreted to be formed since the post-LGM(last glacial maximum), including both the Bølling-Allerød (B/A) Interstadial(12,700~14,700 cal-yrBP), and the Younger Dryas Stadial(11,700~12,900 cal-yrBP). The wild rice seed like Oryza rufipogon found in the middle organic muds of the young fluvial deposits dated after about 15,000 cal-yrsBP, when the transition from the subalpine conifer forest to the deciduous broad-leaved forest was conspicuously evidenced in the upper part of OC-2 palynofloral zone of the in Cheonju Sorori site, In particular the OC-2 palynofloral zone ranging towards the upper part of middle organic muds(peaty muds) is interpreted to be formed in the B/A Interstadial. It is regarded that Cheongju Sorori rice seeds are associated with warm palynological evidences and backswamp insects during the Lastest Glacial, showing appearance of relatively warm climate similar to the present.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.4
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• pp.251-258
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• 2024

This study investigated the effect of bearing aging on the seismic response of a three-span continuous concrete girder bridge with pot bearings installed. The pot bearings were modeled as elastic springs in the longitudinal, transverse, and vertical directions of the bridge to reflect the stiffness of fixed and movable supports. The effect of bearing aging on the seismic response of the bridge was examined by considering two factors: a decrease in the horizontal stiffness of the fixed bearings and an increase in the horizontal stiffness of the movable bearings. The finite element model of the three-span continuous girder bridge was validated by comparing its numerical natural frequencies with the designed natural frequencies. Using artificial ground motions that conform to the design response spectrum specified by the KDS bridge seismic design code, the seismic responses of the bridge's girders and bearings were calculated, considering the bearing stiffness variation due to aging. The results of a numerical analysis revealed that a decrease in the horizontal stiffness of the fixed bearings led to an increase in the absolute maximum relative displacement of the bearings during an earthquake. This increases the risk of the mortar block that supports the bearing cracking and the anchor bolt breaking. However, an increase in the horizontal stiffness of the movable bearings due to aging decreased the absolute maximum shear on the fixed bearings. Despite the shear reduction in the fixed bearings, the aging of the pot bearings change could cause additional tensile bending stress in the girder section above the free bearings, which could lead to unexpected structural damage to the continuous bridge during an earthquake.

• Korean Chemical Engineering Research
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• v.62 no.4
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• pp.355-363
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• 2024

Although copolymer aramid is a fiber with excellent flexural performance, there is no test method to evaluate flexural fatigue performance. Various studies are currently being conducted in korea to develop copolymer aramid, and in order to develop the reliability of aramid fibers to a global level, it is necessary to develop a test method to evaluate the flexural fatigue performance of aramid fibers. In this study, we developed an test equipment and test method that can evaluate the flexural fatigue performance of copolymer aramid and analyzed the flexural fatigue performance of aramid fiber. Flexing rollers are made of ceramic materials and rotating shapes to minimize friction. The diameter of the roller was set to 10 mm by calculating the minimum allowable curvature. The B₁₀ life was calculated through a flexural fatigue test, and the para-aramid was 125,770 cycles, the copolymer aramid was 598,150 cycles, and the aramid nano fiber(ANF) coated copolymer aramid was 589,073 cycles. Through the S-N diagram, the fatigue life relationship according to the load change was confirmed. copolymer aramid fibers exhibit better flexural fatigue performance than para-aramid fibers at high loads. The ANF coated copolymer aramid also exhibits excellent flexural fatigue performance.

• Journal of the Korean Applied Science and Technology
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• v.37 no.3
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• pp.594-603
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• 2020

The aim of this study was to investigate the issue in obese children with a high probability of leading to precocious puberty for they have more advanced skeletal maturation compared to normal children in order to contribute to the health of obese children by identifying the relationship between physique and physical fitness according to their skeletal maturation. A total of 243 obese children between the ages of 10-13 were enrolled as subjects, and the skeletal maturation, which symbolize indicators of biological maturation, were evaluated by using the TW3 method after hand-wrist radiographs, thus classified the skeletal maturation level into retarded group(n=70), normal group(n=128), and advanced group(n=45). A stadiometer and InBody 270 (Biospace, Korea) were used to measure 3 components in physique. A total of 7 components in physical fitness, which included muscular strength, muscular endurance, flexibility, power, cardiovascular endurance, balance, agility, were measured as well. Descriptive statistics and one-way variable analysis (ANOVA) were conducted for data processing using SPSS 25.0, and Duncan's multiple-range method was used for post hoc analysis; and it was considered significant at the level of P< .05. Analysis results of this study may be summarized as follow. First, height and weight in physique factors according to the skeletal maturation between the retarded, normal, and advanced groups in males and females were highly significant. Second, physical fitness comparison according to the skeletal maturation in males were statistically significant in muscular strength, power, and agility whereas muscular strength and balance were statistically significant in females.

• Journal of the Korean Applied Science and Technology
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• v.38 no.1
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• pp.318-331
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• 2021

This study was conducted on the assumption that bone age would be more effective when it comes to physique and physical fitness assessment for adolescents, and the purpose of this study was to identify the differences in physique and physical fitness for students in their adolescence through bone age and chronological age in order to contribute to the well-balanced physique and physical fitness development in adolescents and the health improvement in students. Total 874 adolescents(483 males, 391 females) aged 11~16 were selected as subjects out of the total population of 1100 adolescents aged 6~16 based on the PAPS(Physical Activity Promotion System) and age standards of the TW3 method; and skeletal maturation, which symbolize the indicators of biological maturation, were evaluated by using the TW3(Tanner-Whitehouse 3) method after hand-wrist radiographs, and birth date was used for chronological age. A stadiometer and InBody 270 (Biospace, Korea) were used to measure 2 components in physique. A total of 7 components in physical fitness, which included muscular strength, muscular endurance, flexibility, power, cardiovascular endurance, balance, agility, were measured as well. A independent samples t-test was conducted for data processing using SPSS 25.0, and the significance level was set at p< .05. The study results are as follows. First, bone age and chronological age used for physique comparison in males aged 11 and 12, height and weight showed significant difference; in males aged 13, weight showed signicant difference. Weight and height in females aged 11, and height in females aged 12 showed significant difference. Second, bone age and chronological age used for physical fitness comparison in males aged 11, muscular strength, power, flexibility, cardiovascular endurance showed significant difference; in males aged 12, muscular strength. power, cardiovascular endurance; in males aged 13, flexibility showed significant difference. Muscular strength, power, flexibility, muscular endurance, cardiovascular endurance in females aged 11, and flexibility in females aged 14 showed significant difference. As a result, this study concluded that in a period of rapid skeletal growth, evaluating physique and physical fitness based on bone age is more accurate than evaluating based on chronological age.

• Korean Journal of Ecology and Environment
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• v.45 no.4
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• pp.482-489
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• 2012

Visual monitoring is hard to apply on fish because they are living in a water system. To overcome this problem, acoustic telemetry, which is effective for underwater monitoring, is often used for studying fish behaviors, such as movement distance, route and patterns. In this study, in order to monitor the movement pattern of Squaliobarbus curriculus (family Cyprinidae), we used acoustic telemetry and identified the home range and movement distances. A total of nine individuals were released at two different locations: one is at the estuary barrage (Sc1~3) and the other is at the lower part of Baekjae Weir (Sc4~9), located in Geum River. Approximately, a 70 km section from the estuary barrage was investigated. Fish, which were released at the estuary barrage, utilized up to 12.7 km upstream as home range from the release site. At the lower part of Baekjae Weir, most of the fish moved and stayed within a 7.2 km downstream area, except for Sc6, which moved 53.4 km (linear maximum distance from release site) downstream from the release site. Relatively small sized fish (Sc7~9) did not show any movement. Accumulated movement distance significantly correlated with the standard length of S. curriculus ($r_s$=0.715, p=0.03). Moreover, the standard length of moving fish was significantly larger than that of not moving fish (Mann-Whitney U test, p=0.024). Therefore, the movement distance of S. curriculus has been correlated with fish size; movement distance was increased with the standard fish length. Although the sample size of monitored fish was small, various meaningful data were collected by acoustic telemetry. Consequently, this technique could be a method available for effectively monitoring the behavior and ecology of native Korean and endemic species.

• Korean Journal of Food Science and Technology
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• v.37 no.6
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• pp.882-888
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• 2005

Procedure for analysis of methylmercury in fish was developed, involving addition of HCl, extraction with toluene, and clean-up using L-cystein solution. Obtained extract is analyzed by gas chromatography with electron capture detector using Ulbon HR-Thermon-Hg column. Detection limit and recovery of the method were 0.005mg/kg (expressed as Hg), 98-107 (103%), respectively. Total mercury and methylmercury concentrations in 175 commercial fish samples ranged from [mean-max (mean), unit: mg/kg]: 0.014-1.200 (0.270) and 0.006-0.901 (0.168) in tuna-fish, 0.020-0.934 (0.323) and 0.012-0.553 (0.149) in martin-fish, 0.082-0.782 (0.391) and 0.040-0.436(0.201) in shark, 0,023-0.031 (0.026) and 0,013-0.018 (0.015) in salmon, 0.098-0.193 (0.133) and 0.031-0.015(0.090) in tilefish, and 0,031-0.214 (0.089) and 0.016-0.093 (0.042) in canned tuna respectively. No sample of analyzed fish exceeded 1.0mg/kg wet wt., limit for methylmercury established by Codex. In all species examined, estimated weekly intake was lower than Provisional Tolerable Weekly Intake recommended by the JECFA (the Joint FAO/WHO Expert Committee on Food Additives).

• Journal of Korean society of Dental Hygiene
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• v.2 no.1
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• pp.63-83
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• 2002

The purpose of this study was to serve as a basis for more efficient dental hygienist human resources utilization and for determining some of the right directions for supplementary education for dental hygienists, by examining how they actually worked and what they thought of job-related things. The subjects in this study were 537 dental hygienists who participated in a seminar by the Korea Dental Hygienist Association. After a survey was conducted, the following findings were given: 1. 50.2% of the dental hygienists investigated completed legally required eight-class education. Those who worked in clinics took less supplementary education classes than the others in the other types of dental institutions. The main reason they didn't receive supplementary education was financial burden and uncooperative employers. 73.2% took supplementary education at the association or its branches. The association was most favored by those in clinical sector as a place that provides supplementary education, followed by its branch and university in the order named. And the dental hygienists in public health sector preferred university most, and the next best favored one was the association and its branch in the order named. Those in clinical sector hoped to acquire clinical information on patient management, implant or aesthetics, and the dental hygienists in public health sector wanted to learn about health administration, public oral health operations and oral health education, which were different from what those in clinical sector wanted. 2. Regarding the period of service, 492% had worked for three years or more. This fact suggested that their service term and average age continued to grow. And they thought they would decide the retirement time on their own. 3. The most common yearly income ranged from 12 million won to 16 million won(40.7%). For-those in clinics, yearly income was 14.36 million won, and that of the dental hygienists who had worked for less than 3 years was 12.90 million won. 4. The Korea Dental Hygienist Association was most required to protect the rights and interests of the members and offer new knowledge and technology. 5. The largest group of them were engaged in patient management, and this type of job also was the most favored one for them to do. The greatest number of the dental hygienists in public health sector were in charge of dental treatment. 6. Concerning their turnover rate, 492% had never changed their occupation. Specifically, 70.0% of the respondents who had worked for less than 3 years had have no experience to do that. The time constraints for self-development and conflicts with other workers were the cause of their turnover. Those in dental hospital and general hospital changed their occupation chiefly due to the lack of time for self-development, and for the dental hygienists in clinics, the conflicts with other workers were the main reason. The above-mentioned findings suggested that the way the dental hygienists looked at things was undergoing change. The service area made a difference to their preference for the type of supplementary education and institution in charge of it, as those in public health and clinical sectors had a different opinion. And the dental hygienists in clinical sector had a different opinion as well, according to service area, about salaries, reason of not taking supplementary education, preferred type of supplementary education, cause of turnover, and type of occupation to which they hoped to change employment. To utilize and supply human resources in a more stabilized manner, job description should be more segmented, standardized and classified clearly, and dental hygienists should be motivated to perform their substantial jobs, including oral disease prevention, oral prophylaxis and oral health education. To make it happen, it seems that dentists are required to have a clear understanding of dental hygienist job and to change the way they look at it.

• Applied Microscopy
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• v.40 no.1
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• pp.37-45
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• 2010

Captured wild specimens of the big white-toothed shrew, Crocidura lasiura were classified into three age classes by tooth wear and height of molars, and seasonal variations of breeding and reproductive organs were examined. Juveniles had not tooth wear in molars and height of the third molars were lower than the first and second molars, and had only non-breeding condition. Young adults had little tooth wear and the third molars reached to the first and second molars, and old adults had heavy tooth wear in molars, young adults and old adults had breeding or non-breeding condition according to the season. On the basis of histological examination, seasonal variations of breeding were confirmed that breeding condition of young and old adult males were continued from early February to early October although the breeding activity was the highest in April, that of females were continued from the end of March to October, males reached sexual maturity earlier than females. Whereas the breeding condition seems to cease for non-breeding season because of the deficiency of food resources, soil invertebrates. Young and old adult males of the breeding season had large testes with enlarged seminiferous tubules that were filled with numerous germ cells, and expanded caudal epididymides with a vast number of spermatozoa, and were more than 10.0 g in the body weight and 0.03 g in the testis and epididymis weight. The females of the breeding season were pregnant condition with 4~6 litters or had the Graafian follicles and the corpus lutea in the ovary, and were more than 9.6 g in the body weight.