• The Journal of Internal Korean Medicine
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• v.42 no.6
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• pp.1255-1268
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• 2021

Objectives: This study aimed to analyze the healthcare utilization behavior of patients visiting the department of Korean internal medicine in the Korean medicine hospital of Wonkwang University in Jeon-ju from July 2018 to June 2021. Methods: We retrospectively analyzed the medical records of 26,108 patients and sorted the data by period, month, visiting types, new or returning types, sex, and age group. IBM SPSS 26.0 and the R 4.05 'changepoint' package were used with various statistical methods, such as Independent t-test, Mann-Whitney test, Chi-square test, Simple regression analysis. The P-value was set at 0.05. Results and Conclusions: Females outnumbered males regardless of period, and the ratio of females fell after COVID-19. Regardless of visiting types, patients in their 50s, 60s, and 70s outrated any other age group. The average number of females among the returning patients decreased significantly after COVID-19, but did not in males. Outpatients under 10 and in their 10s decreased significantly after COVID-19, as did inpatients in their 40s and 60s. The average duration of hospitalization was extended significantly after COVID-19. The number of outpatients and inpatients decreased as time passed after COVID-19. We expect that the results of this study will be used as reference materials in analyzing the effects of COVID-19 on healthcare utilization.

• Journal of Digestive Cancer Research
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• v.4 no.1
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• pp.32-35
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• 2016

Pseudomyxoma peritonei (PMP) is a rare clinical syndrome characterized by profuse jelatinous materials in the abdominal cavity and pelvis with mucinous implants on the peritoneal surface. There are some studies for serum tumor markers, including carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9) and carbohydrate antigen 125 (CA125), to assess the risk of recurrence following cytoreductive surgery and intraperitoneal chemotherapy. However, rare cases were reported about recurrence with increasing serum CEA levels. Herein, we report a case of recurrence of PMP according to serially elevated serum CEA.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.5
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• pp.489-500
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• 2004

Statement of problem: The use of zirconia prostheses fabricated with CAD/CAM system is on an increasing trend in dentistry. However, evaluation of the fit related to internal relief and marginal reproducibility of zirconia has not been reported. Purpose : This study was to evaluate the fit related to internal relief and marginal reproducibility of zirconia core fabricated with CAD/CAM system. Materials and methods: The evaluation was based on 30 zirconia cores and 5 IPS-Empress2 cores. Zirconia cores were fabricated in different conditions of internal relief(0, 10, 20, 30, 40 and $50{\mu}m$), and IPS-Empress2 cores were fabricated in accordance with the manufacturer's instructions. Before cementation, the marginal discrepancies or cores were measured on metal die. And then, each core was cemented to stone die, embedded in an acrylic resin and sectioned in two planes(mesiodistally and labiopalatally). The internal gaps were measured at the margin and axial surface. Measurements for the marginal discrepancies, the internal marginal gaps and the internal axial gaps were performed under a measuring microscope(Compact measuring microscope STM5; Olympus, Japan) at a magnification of ${\times}100$. In addition, the marginal conagurations of metal die, zirconia core and IPS-Empress2 core were examined with SEM(S-2700, Hitachi, Japan). Results : Within the limits of this study the results were as follows. 1. Compared with IPS-Empress2 cores, the marginal discrepancies of zirconia cores had no significant differences. the internal marginal gaps were statistically smaller and the internal axial gaps were statistically larger in each condition of internal relief. 2. The marginal discrepancies and the internal marginal gaps of zirconia cores had no significant differences related to the conditions of internal relief(P>0.05). 3. The internal axial gaps of zirconia cores with $0{\sim}20{\mu}$m for internal relief were significantly larger than that with $50{\mu}m$ (P<(0.0001). 4. SEM micrographs showed favorable marginal reproducibility of zirconia core and smooth texture on the milling surface. Conclusion: The marginal discrepancy and the internal gaps of zirconia core were clinically acceptable and the milling surface was showed smooth texture. For fabrication of the durable esthetic restoration, further investigations on complex design of core, milling accuracy, compatability of enamel porcelain and porcelain firing seems to be needed.

• Korean Journal of Optics and Photonics
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• v.31 no.5
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• pp.205-212
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• 2020

In the performance of a wind turbine system, the blades play a vital role. However, they are susceptible to damage arising from complex and irregular loading (which may even cause catastrophic collapse), and they are expensive to maintain. Therefore, it is very important both to find defects after blade manufacturing is completed and to find damage after the blade is used for a certain period of time. This study provides a new perspective for the detection of internal defects in glass-fiber- and carbon-fiber-reinforced panels, which are used as the main materials in wind turbine blades. A gap or fracture between fiber-reinforced materials, which may occur during blade manufacturing or operation, is simulated by drilling a hole 5 mm in diameter in the middle layer of the laminated material. Then, a digital-image-correlation (DIC) method is used to detect internal defects in the blade. Tensile load is applied to the fabricated specimen using a tensile tester, and the generated changes are recorded and analyzed with the DIC system. In the glass-fiber-reinforced laminated specimen, internal defects were detected from a strain value of 5% until the end of the experiment, while in the case of the carbon-fiber-reinforced laminated specimen, internal defects were detected from 1% onward. It was proved using the DIC system that the defect was detected as a certain level of strain difference developed around the internal defects, according to the material properties.

• The Journal of Internal Korean Medicine
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• v.23 no.1
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• pp.99-106
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• 2002

Background : Nowadays a lot of research is based on natural substances or materials world wide since many kinds of side effects are accompanied by anti tumor chemotherapy. In Chinese medicine, Dioscorea bulbifera L is widely used to treat many kinds of cancer, but in Korea it is rarely used. Therefore, we need to scientifically identify anti tumor effects of Dioscorea bulbifera L. Objective : We aimed to identify anti tumor effects of Dioscorea bulbifera L on the stomach cancer cells through molecular biological methods. Materials & Methods : We used AGS, a stomach cancer cell from American Type Culture Collection. We injected the boiled extract of Dioscorea bulbifera L 5 ul(sample 1), 10ul(sample 2) to cultured media(ml) for 0,6,12,18,24 hours. We measured the killing effect on stomach cancer cells through Tryphan blue exclusion test and suppressive effect on viability of stomach cancer cells via MTT assay. Results : Tryphan blue exclusion test showed that each test group killed more stomach cancer cells than the controlled group with a dosage-dependent, but not significantly. MTT assay showed that each test group had a more suppressive effect on viability of stomach cancer cells than the controlled group without a dosage-independent, but not significantly. The cell cycle analysis via flow cytometry showed that the test group extended cell cycle, and there was no peak in M phase, the number of sub G1, G0, G1 phase cells increased a little, but not significantly. Conclusion : This experiment showed that Dioscorea bulbifera L. has an anti-tumor effect, but not significantly. This is in vitro experiment and basic experiment on Dioscorea bulbifera L. We hope more progressive researches on Dioscorea bulbifera L. will be conducted and its anti tumor will be more accurately identified.

• Journal of Korean Elementary Science Education
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• v.35 no.1
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• pp.123-135
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• 2016

Interest is one of the important factors in science education. The purpose of this study was to investigate factors affecting the follow-up interest of elementary school students on topics of 'Small Organisms' World'. The follow-up interests of the students on the topic were grouped into three categories; the developed-expanded-deepened (EDD), the simply expanded and maintained (SEM), and the stoped or decreased (SD) types. Each types had specific distinguishing features. Through the examination of students' responses and the in-depth interviews, the factors affecting on the follow-up interests of the students were analyzed. The factors were classified into two types of the external factor and the internal one. While the external factors were mainly related to the instructional materials used in science class and teaching methods, the internal factors were related to the desire for knowing, prior knowledge, students' experience and attitude toward the topics of science. In relation to the types of the follow-up interests, these factors were affected by different causes. The EDD type was most affected by internal factors, such as desire for knowing and prior knowledge. The SEM type was shown to be most affected by external factors, such as instructional materials. The SD type was mainly influenced by external factors, such as teaching methods. From the analysis of internal factors, it was revealed that the attitude and the prior knowledge about the topic are related with the follow-up interests. There was a positive relationship between the levels of science attitude and science knowledge. The students who had EDD type had a higher level of attitude and knowledge. However, there were some students who had higher level of scientific knowledge with SD type. The results of in-depth interviews showed that they were influenced by negative perceptions about science and stress on their grades. In conclusion, each follow-up interest type were caused by the external factors contained in the processes of the science class and the internal ones associated with the individual features and were influenced by the science class. So, the teacher should help the students be able to have the EDD type of follow-up interest which is persisted even after the completion of the science curriculum. For this, when the teachers design science curriculum and plan lesson, they should consider both internal and external factors significantly influencing the students' follow-up interests.

• Journal of Gastric Cancer
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• v.23 no.4
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• pp.574-583
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• 2023

Purpose: Gastric cancer (GC) is among the most prevalent and fatal cancers worldwide. National cancer screening programs in countries with high incidences of this disease provide medical aid beneficiaries with free-of-charge screening involving upper endoscopy to detect early-stage GC. However, the coronavirus disease 2019 (COVID-19) pandemic has caused major disruptions to routine healthcare access. Thus, this study aimed to assess the impact of COVID-19 on the diagnosis, overall incidence, and stage distribution of GC. Materials and Methods: We identified patients in our hospital cancer registry who were diagnosed with GC between January 2018 and December 2021 and compared the cancer stage at diagnosis before and during the COVID-19 pandemic. Subgroup analyses were conducted according to age and sex. The years 2018 and 2019 were defined as the "before COVID" period, and the years 2020 and 2021 as the "during COVID" period. Results: Overall, 10,875 patients were evaluated; 6,535 and 4,340 patients were diagnosed before and during the COVID-19 period, respectively. The number of diagnoses was lower during the COVID-19 pandemic (189 patients/month vs. 264 patients/month) than before it. Notably, the proportion of patients with stages 3 or 4 GC in 2021 was higher among men and patients aged ≥40 years. Conclusions: During the COVID-19 pandemic, the overall number of GC diagnoses decreased significantly in a single institute. Moreover, GCs were in more advanced stages at the time of diagnosis. Further studies are required to elucidate the relationship between the COVID-19 pandemic and the delay in the detection of GC worldwide.

• Korean Journal of Materials Research
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• v.23 no.1
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• pp.67-71
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• 2013

Porous $Al_2O_3$ dispersed with nano-sized Cu was fabricated by freeze-drying process and solution chemistry method using Cu-nitrate. To prepare porous $Al_2O_3$, camphene was used as the sublimable vehicle. Camphene slurries with $Al_2O_3$ content of 10 vol% were prepared by milling at $50^{\circ}C$ with a small amount of oligomeric polyester dispersant. Freezing of the slurry was done in a Teflon cylinder attached to a copper bottom plate cooled to $-25^{\circ}C$ while unidirectionally controlling the growth direction of the camphene. Pores were subsequently generated by sublimation of the camphene during drying in air for 48 h. The green body was sintered in a furnace at $1400^{\circ}C$ for 1 h. Cu particles were dispersed in porous $Al_2O_3$ by calcination and hydrogen reduction of Cu-nitrate. The sintered samples showed large pores with sizes of about $150{\mu}m$; these pores were aligned parallel to the camphene growth direction. Also, the internal walls of the large pores had relatively small pores due to the traces of camphene left between the concentrated $Al_2O_3$ particles on the internal wall. EDS analysis revealed that the Cu particles were mainly dispersed on the surfaces of the large pores. These results strongly suggest that porous $Al_2O_3$ with Cu dispersion can be successfully fabricated by freeze-drying and solution chemistry routes.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.3
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• pp.219-224
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• 2020

Al₂O₃ powders with particle sizes of 0.35 ㎛, 0.5 ㎛, 1.5 ㎛, and 2.5 ㎛ are deposited onto glass and Cu substrates using the aerosol deposition (AD) process. The deposition characteristics of Al₂O₃ films using those four types of Al₂O₃ powders are investigated to determine the influence of the particle size on the films. To observe detailed micro-structures of the films, the cross-section and surface morphology are observed. Then, the crystalline size and internal strain are calculated from X-ray diffraction peaks in order to confirm the hammering effect as well as the micro-strain during the AD deposition. From the above results, deposition mechanisms related to the particle size are studied. The results of this study indicate the optimal particle size and formation mechanisms for dense Al₂O₃ film with a smooth surface roughness as well as for a porous Al₂O₃ film with a rough surface roughness.

• Nuclear Engineering and Technology
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• v.52 no.5
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• pp.1013-1021
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• 2020

A combination of simultaneous thermal analysis, evolved gas analysis and non-ambient XRD techniques was used to characterise and investigate the conversion reactions of ammonium uranates into uranium oxides. Two solid phases of the ternary system NH₃ - UO₃ - H₂O were synthesised under specified conditions. Microspheres prepared by the sol-gel method via internal gelation were identified as 3UO₃·2NH₃·4H₂O, whereas the product of a typical ammonium diuranate precipitation reaction was associated to the composition 3UO₃·NH₃·5H₂O. The thermal decomposition profile of both compounds in air feature distinct reaction steps towards the conversion to U₃O₈, owing to the successive release of water and ammonia molecules. Both compounds are converted into α-U₃O₈ above 550 ℃, but the crystallographic transition occurs differently. In compound 3UO₃·NH₃·5H₂O (ADU) the transformation occurs via the crystalline β-UO₃ phase, whereas in compound 3UO₃·2NH₃·4H₂O (microspheres) an amorphous UO₃ intermediate was observed. The new insights obtained on these uranate systems improve the information base for designing and synthesising minor actinide-containing target materials in future applications.