• The Bulletin of The Korean Astronomical Society
• /
• v.46 no.2
• /
• pp.58.1-59
• /
• 2021

Exploration of asteroids' internal structure is essential for understanding their evolutional history. It also provides a fundamental information about the history of coalescence and collision of the solar system. Among several models of the internal structures, the rubble-pile model, confirmed by the near-Earth asteroid (25143) Itokawa by Hayabusa mission [1], is now widely regarded as the most common to asteroids with size ranging from 200 m to 10 km [2]. On the contrary, monolithic and core-mantle structures are also possible for small asteroids [3]. It is, however, still challenging to look through the interior of a target object using remote-sensing devices. In this presentation, we introduce our ongoing research conducted at Seoul National and propose an idea to infer the internal structure of Apophis using available instruments. Itokawa's research provides an important benchmark for Apophis exploration because both asteroids have similar size and composition [4][5]. We have conducted research on Itokawa's evolution in terms of collision and space weathering. Space weathering is the surface alteration process caused by solar wind implantation and micrometeorite bombardment [6]. Meanwhile, resurfacing via a collision acts as a counter-process of space weathering by exposing fresh materials under the matured layer and lower the overall degree of space weathering. Therefore, the balance of these two processes determine the space weathering degrees of the asteroid. We focus on the impact evidence on the boulder surface and found that space weathering progresses in only 100-10,000 years and modifies the surface optical properties (Jin & Ishiguro, KAS 2020 Fall Meeting). It is important to note that the timescale is significantly shorter than the Itokawa's age, suggesting that the asteroid can be totally processed by space weathering. Accordingly, our result triggers a further discussion about why Itokawa indicates a moderately fresh spectrum (Sq-type denotes less matured than S-type). For example, Itokawa's smooth terrains show a weaker degree of space weathering than other S-type asteroids [7]. We conjecture that the global seismic shaking caused by collisions with >1 mm-sized interplanetary dust particles induces granular convection, which hinders the progression of space weathering [8]. Note that the efficiency of seismic wave propagation is strongly dependent on the internal structure of the asteroid. Finally, we consider possible approaches to investigate Apophis's internal structure. The first idea is studying the space weathering age, as conducted for Itokawa. If Apophis indicates a younger age, the internal structure would have more voids [9]. In addition, the 2029 close encounter with Earth provides a rare natural opportunity to witness the contrast between before and after the event. If the asteroid exhibits a slight change in shape and space weathering degree, one can determine the physical structure of the internal materials (e.g., rubble-pile monolithic, thick or thin regolith layer, the cohesion of the materials). We will also consider a possible science using a seismometer.

• Economic and Environmental Geology
• /
• v.56 no.6
• /
• pp.675-695
• /
• 2023

The tracksite of dinosaurs and pterosaurs in Sanbuk-dong of Gunsan is the largest early Cretaceous dinosaur footprint fossil site in Korea, and all the footprints are important evidence indicating that large ornithopod and theropod dinosaurs inhabited the Korean peninsula during the early Cretaceous. The Sanbuk-dong site was covered with waterproof sheet in an outdoor environment until the installation of a protective enclosure in 2021. As a result, various factors such as shear force, load reduction, temperature and humidity fluctuations, acid rain, salinity and microorganisms have complexly interacted in the substrate of fossils, exacerbating the damage to footprints. For 159 footprints in 12 trackways among the footprints found in the site, the damage types were classified in detail and the level of each damage was assessed. The damages were classified into 6 types through the classification of deterioration degree of individual footprints. As a result of ultrasonic physical property evaluation on the surface of the fossil site, most of these footprints are in the completely weathered (CW) stage. Furthermore, various weathering patterns were observed in the study area, and surface contaminants were analyzed along the stratigraphy. Although the patterns of freshness and contaminants varied at different points within the fossil site, the chemical compositions were similar. Based on the results, an efficient conservation management system for dinosaur footprint fossils was established, and a conservation treatment type for each footprint was proposed.

• Journal of Life Science
• /
• v.33 no.12
• /
• pp.1062-1073
• /
• 2023

Although depression is a common psychiatric disorder that negatively affects individuals and societies, its exact pathogenesis is not well understood. Stress is a major risk factor for depression and is known to increase susceptibility by triggering inflammation. Indeed, many preclinical and clinical studies have suggested a strong link between depression and inflammation. Depression is associated with increased levels of pro-inflammatory cytokines, such as interleukin (IL-)1β, IL-6, IL-12, tumor necrosis factor-α, and interferon-γ, and decreased levels of the anti-inflammatory IL-4, IL-10, and transforming growth factor-β. Administering pro-inflammatory cytokines causes depression-like behaviors in rodents. Conversely, administering anti-inflammatory drugs appears to ameliorate depressive symptoms. Although the importance of inflammation as a mediator of depression has been demonstrated, the mechanisms by which inflammation is activated in depression remain unclear. To address this issue, recent studies have focused on the importance of stress-induced sterile inflammation. Sterile inflammation refers to the activation of inflammatory processes due to physical and/or psychological stress in the absence of pathogens. Stress promotes the release of endogenous factors known as damage-associated molecular patterns (DAMPs), thereby triggering sterile inflammation. In turn, DAMPs are recognized by pattern recognition receptors, leading to the production of pro-inflammatory cytokines. Here, we review the role of DAMPs in depression based on preclinical and clinical evidence on the dysregulation of sterile inflammation.

• Journal of Service Research and Studies
• /
• v.14 no.1
• /
• pp.108-123
• /
• 2024

In particular, as the current educational institutions are becoming more competitive, universities need to make efforts to survive the fierce competition by improving their service qualities. In this situation, this study was conducted to confirm the effect of international students' evaluation of university service quality on university loyalty through university satisfaction and service engagements, And several implications can be suggested as follows. First, the dimensions of university service quality were identified as important factors that had a great influence on the university satisfaction of international students. Among the service quality dimensions, support services related to international students were found to be the most important variable in university satisfaction. The school's efforts to solve the inconvenience of international students and the grievances of students who feel difficulties that their own students do not feel are considered a very important factor in the satisfaction of international students. Second, it was found that international students' class engagement or friendship engagement can be increased through satisfaction with the school, and eventually, the increased engagements affect university loyalty. In particular, it has been verified that for international students, the loyalty of the school can be increased by establishing friendships with students from various countries and participating in various school programs. Finally, according to the purposes of studying abroad, the difference was confirmed between the groups studying for academic development and better employment and the group employed for overseas experience and immigration.

• Clinics in Shoulder and Elbow
• /
• v.26 no.4
• /
• pp.343-350
• /
• 2023

Background: Our purpose was to evaluate a custom reverse total shoulder arthroplasty glenoid baseplate for severe glenoid deficiency, emphasizing the challenges with this approach, including short-term clinical and radiographic outcomes and complications. Methods: This was a single-institution, retrospective series of 29 patients between January 2017 and December 2022 for whom a custom glenoid component was created for extensive glenoid bone loss. Patients were evaluated preoperatively and at intervals for up to 5 years. All received preoperative physical examinations, plain radiographs, and computed tomography (CT). Intra- and postoperative complications are reported. Results: Of 29 patients, delays resulted in only undergoing surgery, and in three of those, the implant did not match the glenoid. For those three, the time from CT scan to implantation averaged 7.6 months (range, 6.1-10.7 months), compared with 5.5 months (range, 2-8.6 months) for those whose implants fit. In patients with at least 2-year follow-up (n=9), no failures occurred. Significant improvements were observed in all patient-reported outcome measures in those nine patients (American Shoulder and Elbow Score, P<0.01; Simple Shoulder Test, P=0.02; Single Assessment Numeric Evaluation, P<0.01; Western Ontario Osteoarthritis of the Shoulder Index, P<0.01). Range of motion improved for forward flexion and abduction (P=0.03 for both) and internal rotation up the back (P=0.02). Pain and satisfaction also improved (P<0.01 for both). Conclusions: Prolonged time (>6 months) from CT scan to device implantation resulted in bone loss that rendered the implants unusable. Satisfactory short-term radiographic and clinical follow-up can be achieved with a well-fitting device. Level of evidence: III.

• Journal of the Korean Chemical Society
• /
• v.68 no.3
• /
• pp.160-175
• /
• 2024

The purpose of this study is to examine the effects of a Chemistry I class based on an artificial intelligence (AI) classification model. To achieve this, the research investigated the development and application of a class utilizing an AI classification model in Chemistry I classes conducted at D High School in Gyeongbuk during the first semester of 2023. After selecting the curriculum content and AI tools, and determining the curriculum-AI integration education model as well as AI hardware and software, we developed detailed activities for the program and applied them in actual classes. Following the implementation of the classes, it was confirmed that students' self-efficacy improved in three aspects: chemistry concept formation, AI value perception, and AI-based maker competency. Specifically, the chemistry classes based on text and image classification models had a positive impact on students' self-efficacy for chemistry concept formation, enhanced students' perception of AI value and interest, and contributed to improving students' AI and physical computing abilities. These results demonstrate the positive impact of the Chemistry I class based on an AI classification model on students, providing evidence of its utility in educational settings.

• Journal of Chest Surgery
• /
• v.9 no.1
• /
• pp.1-9
• /
• 1976

The present. study reports four cases of congenital heart diseases, who received open heart surgery by the Sarn's Heart-Lung-Machine in the department of Thoracic Surgery, Hanyang University Hospital during the period between July 1975 and May 1976. The Heart-Lung-Machine consisted of the Sarn's five head roller pump motor system (model 5000), heat exchanger, bubble trap, the Rygg-Kyvsgaard oxygenator, and monitors. The priming of pump oxygenator was carried out by the hemodilution method using Hartman's solution and whole blood. Of the four cases of the heart diseases, three whose body weight were below 30kg, received the partial hemodilution priming and the remaining one whose body weight was 52kg received the total hemodilution priming with Hartman's solution alone. The rate of hemodilution was in the average of 60.5ml/kg. Extracorporeal circulation was performed at the perfusion flow rate of the average 94.0ml/kg/min, and at the moderate hypothermia between 35'5"C and 30'5"C of the rectal temperature. In the total cardiopulmonary bypass, arterial blood pressure was anged between 30 mmHg and 85 mmHg, generally maintaining over 60 mmHg and venous pressure was measured between 4 and $23cmH_2O$, generally maintaining below $10cmH_2O$. The first case: The patient, a nine year old girl having the symptoms and physical signs typical to cardiac anomaly was definitely diagnosed as isolated pulmonary stenosis through the cardiac catheterization. There was, however, no cyanosis, no pathological finding by X-ray and E.C.G. tracings. The valvulotomy was performed through the arteriotomy of pulmouary artery under the total cardiopulmonary bypass. Postoperative course of the patient was uneventful, and murmur and the clinical symptoms disappeared. The second case: A 12 year old boy with congenital heart anomaly was positively identified as having ventricular septal defect through the cardiac catheterization. As in the case with the first case, the patient exhibited the symptoms and physical signs typical to cardiac anomaly, but no pathological abnormality by X-ray and E.C.G. tracings. The septal defect was localized on atrioventricular canal and was 2 by 10 mm in size. The septal defect was closed by direct simple sutures under the cardiopulmonary bypass. Postoperative hemodynamic study revealed that the pressure of the right ventricle and pulmonary artery were decreased satisfactory. Postoperative course of the patient was uneventful, and murmur and the clinical symptoms disappeared. The third case: The patient, a 19 year old girl had been experienced the clinical symptoms typical to cardiac anomaly for 16 years. The pink tetralogy of Fallot was definitey diagnosed through the cardiac catheterization. The patient was placed on an ablolute bed rest prior to the operation because of severe exertional dyspnea, fatigability, and frequent syncopal attacks. However, she exhibited very slight cyanosis. Positive findings were noted on E.C.G. tracings and blood picture, but no evidence of pathological abnormality on X-ray was observed. All of the four surgical approaches such as Teflon patch closure (3 by 4cm in size) of ventricular septal defect, myocardial resection of right ventricular outflow tract, valvulotomy of pulmonary valvular stenosis, and pericardial patch closing of ventriculotomy wound were performed in 95 minutes under the cardiopulmonary bypass. Postoperative hemodynamic study revealed that the pressure of the right ventricle was decreased and pulmonary artery was increased satisfactorily. Postoperative course of the patient was uneventful, and murmur and the clinical symptoms disappeared. The fourth case: The patient, a 7 1/4 year old girl had the symptoms of cardiac anomaly for only three years prior to the operation. She was positively identified as having acyanotic tetralogy of Fallot by open heart surgery. The patient showed positive findings by X-ray and E.C.G. tracings, but exhibited no cyanosis and normal blood picture. All of the three surgical approaches, such a myocardial resection of hypertrophic sight ventricular outflow tract, direct suture closing of ventricular septal defect and pericardial patch closing of ventriculotomy wound were carried out in 110 minutes under the cardiopulmonary bypass. Postoperative hemodynamic study revealed that the pressure of the right ventricle was decreased and pulmonary artery was increased satisfactorily. Postoperative course of the patient was uneventful, and the symptoms disappeared.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.11 no.1
• /
• pp.42-55
• /
• 2008

Purpose: A new health policy, referred to as the National Health Screening Program for Infants and Children, was launched in November 2007 by the Ministry of Health and Welfare and National Health Insurance Corporation in Korea. We have developed a nutrition-counseling program that was incorporated into this project. Methods: We reviewed the nutritional guidelines published by The Korean Pediatric Society and internationally well-known screening programs such as Bright Future in the United States. We also reviewed the recent Korean national surveys on nutritional issues, including the Korea National Health and Nutrition Examination Survey (KNHANES) and the 2005 National Survey of Physical Body and Blood Pressure in Children and Adolescents. The development of questions, pamphlets, computer programs, and manuals for doctors was carried out after several meetings of researchers and governmental officers. Results: We summarized the key nutritional issues according to age, including breastfeeding in infants, healthier complementary feeding, and prevention of iron deficiency anemia, establishment of healthier diets, as well as dietary prevention of overweight children with an emphasis on physical exercise. We have constructed a new Korean nutrition questionnaire and an anticipatory guidance program based on the primary care schedule of visits at 4, 9, 18, 30, and 60 months of age. Five to eight questions were asked at each visit and age-matched pamphlets for parents and guidelines for doctors were provided. Conclusion: We developed a nutrition-counseling program based on recent scientific evidence for Korean infants and children. Further research on this national program for screening the nutritional problems in detail and setting the therapeutic approaches may help identify areas of success as well as those that need further attention.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.22 no.1
• /
• pp.53-66
• /
• 1980

The research work is concerned with the analytical and experimental studies on the heat transfer phenomenon around the underground concrete digester used for biogas production Systems. A mathematical and computational method was developed to estimate heat losses from underground cylindrical concrete digester used for biogas production systems. To test its feasibility and to evaluate thermal parameters of materials related, the method was applied to six physical model digesters. The cylindrical concrete digester was taken as a physical model, to which the model,atical model of heat balance can be applied. The mathematical model was transformed by means of finite element method and used to analyze temperature distribution with respect to several boundary conditions and design parameters. The design parameters of experimental digesters were selected as; three different sizes 40cm by 80cm, 80cm by 160cm and l00cm by 200cm in diameter and height; two different levels of insulation materials-plain concrete and vermiculite mixing in concrete; and two different types of installation-underground and half-exposed. In order to carry out a particular aim of this study, the liquid within the digester was substituted by water, and its temperature was controlled in five levels-35。 C, 30。 C, 25。 C, 20。C and 15。C; and the ambient air temperature and ground temperature were checked out of the system under natural winter climate conditions. The following results were drawn from the study. 1.The analytical method, by which the estimated values of temperature distribution around a cylindrical digester were obtained, was able to be generally accepted from the comparison of the estimated values with the measured. However, the difference between the estimated and measured temperature had a trend to be considerably increased when the ambient temperature was relatively low. This was mainly related variations of input parameters including the thermal conductivity of soil, applied to the numerical analysis. Consequently, the improvement of these input data for the simulated operation of the numerical analysis is expected as an approach to obtain better refined estimation. 2.The difference between estimated and measured heat losses was shown to have the similar trend to that of temperature distribution discussed above. 3.It was found that a map of isothermal lines drawn from the estimated temperature distribution was very useful for a general observation of the direction and rate of heat transfer within the boundary. From this analysis, it was interpreted that most of heat losses is passed through the triangular section bounded within 45 degrees toward the wall at the bottom edge of the digesten Therefore, any effective insulation should be considered within this region. 4.It was verified by experiment that heat loss per unit volume of liquid was reduced as the size of the digester became larger For instance, at the liquid temperature of 35˚ C, the heat loss per unit volume from the 0. 1m$^3$ digester was 1, 050 Kcal/hr m$^3$, while at for 1. 57m$^3$ digester was 150 Kcal/hr m$^3$. 5.In the light of insulation, the vermiculite concrete was consistently shown to be superior to the plain concrete. At the liquid temperature ranging from 15。 C to 350 C, the reduction of heat loss was ranged from 5% to 25% for the half-exposed digester, while from 10% to 28% for the fully underground digester. 6.In the comparison of heat loss between the half-exposed and underground digesters, the heat loss from the former was fr6m 1,6 to 2, 6 times as much as that from the latter. This leads to the evidence that the underground digester takes advantage of heat conservation during winter.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.44 no.6
• /
• pp.162-176
• /
• 2016

The experience and play activities in forest spaces have played an effective role in children's growth and development, therefore, many studies and projects related to forest activity space have progressed actively. However, the focus of previous research has been merely on the effectiveness of forest activity but little on providing the basis for the spatial design of these types of forest activity spaces. Thus, this study aims to identify the relationship between children's developmental play activity and the physical characteristics of forest activity spaces for evidence-based design. First of all, indicators for Cognitive-Social play(CSP) was selected and forest spaces were categorize into play facility spaces and forest spaces. More detailed environmental characteristics of each space were 'play area' and 'paving materials' for play facilities and 'density of tree and shrub', 'slope', 'paving materials' and 'fixing and type of natural loose parts' for forest space. Through environmental inventory and behavior observation, the types of play behaviors and the occurrence frequency of children aged four to five were collected and analyzed. The results were as follows: 1) In play facility spaces, play behaviors occurred at a high frequency at the facility playground with play facilities and sand area. In terms of CSP, functional-solitary and functional-parallel plays occurred predominantly. 2) In forest spaces, various play behaviors occurred at high frequency in the environment with low density planting and various natural loose parts. For CSP, functional-group and symbolic-group plays occurred at a high frequency. 3) Symbolic-group play appeared to be highly affected by environmental characteristics like tree area of scatter density or less, 10~20 degree slope, and the presence of fixed large stumps. In conclusion, this study provides standards of physical environmental characteristics for forest activity space design through direct observation and analysis of children's play behaviors.