1.Effect of investment materials on 3-point flexural strength of heat pressed zirconia core
Tae-Yeon KIM ; Seha KIM ; Jeong-Hui JI ; Byoung gu LIM ; Sung Geun OH ; Jaewoo SHIN ; Junghwan LEE ; Min-Ho LEE ; Tae-Sung BAE
Korean Journal of Dental Materials 2020;47(4):211-220
The purpose of this study was to evaluate the effect of the reaction between investment material and zirconia on the strength of zirconia in the application of heat-pressing method. Sixty specimens were cut (24 mm×4 mm×0.5 mm) into plates from Zirtooth ™ Multi O-9814 block (∅98×14T, HASS, Gangwondo, Korea) and sintered at 1450℃. Specimens were divided into 6 subgroups according to the depending on the investement material; (a) UN group (Control), (b) PH group (Prime vest HS), (c) CP group (Calibra-press), (d) BV group (BC-Vest), (e) MH group (Microstar-HS), (f) F1 group (Formula 1). Five investment materials were buried according to the procedure recommended by the manufacturer and left at room temperature for 30 minutes. The investment mold was dried and maintained at an elevated temperature of 850℃ for 50 minutes. Then, Amber Lisi-POZ LT (HASS) was placed in a thermoformed electric furnace (Programat EP3000/G2, Ivoclar Vivadent, Schaan, Liechtenstein) together with the mold, heated to 915℃ at an elevation temperature of 45℃/min, and moored for 15 minutes. The specimens were loaded to fracture in a universal testing machine and the fracture surface was examined by a field-emission scanning electron microscopy (FE-SEM). The surface of the zirconia specimen with the investment material was analyzed by energy dispersive X-ray spectroscopy (EDS). The 3-point flexural strength test showed the highest value (1265.5 MPa) in the UN group and the lowest value (756.1 MPa) in the F1 group. As a result of EDS analysis, the largest amount of Si was detected in the F1 group, and the most interfacial changes occurred as a result of FE-SEM analysis. It was concluded that when the zirconia is buried with the investment material and the heat press molding is performed, the state of the interface is changed due to the investment material at the bonding interface while the strength is lowered.
2.Hard Ticks as Vectors Tested Negative for Severe Fever with Thrombocytopenia Syndrome in Ganghwa-do, Korea during 2019-2020
Kyoung JIN ; Yeon-Ja KOH ; Seong Kyu AHN ; Joonghee CHO ; Junghwan LIM ; Jaeyong SONG ; Jinyoung LEE ; Young Woo GONG ; Mun Ju KWON ; Hyung Wook KWON ; Young Yil BAHK ; Tong-Soo KIM
The Korean Journal of Parasitology 2021;59(3):281-289
This study aimed to characterize the seasonal abundance of hard ticks that transmit severe fever with thrombocytopenia syndrome virus from April to November 2019 and 2020 on Ganghwa-do, Incheon Metropolitan City, Korea. The ticks were collected at grassland, grave site, copse and mountain road using a collection trap method. The ixodid hard ticks comprising three species (Haemaphysalis longicornis, H. flava, and Ixodes nipponensis) collected were 6,622 in 2019 and 3,811 in 2020. H. longicornis was the most frequent (97.9% in 2019 and 96.0% in 2020), followed by H. flava (2.0% and 3.0% in 2019 and 2020, respectively) and I. nipponensis (less than 0.1%). Our study demonstrated that seasonal patterns of the tick populations examined for two years were totally unsimilar. The hard ticks tested using RT-qPCR were all negative for severe fever with thrombocytopenia syndrome virus.
3.Hard Ticks as Vectors Tested Negative for Severe Fever with Thrombocytopenia Syndrome in Ganghwa-do, Korea during 2019-2020
Kyoung JIN ; Yeon-Ja KOH ; Seong Kyu AHN ; Joonghee CHO ; Junghwan LIM ; Jaeyong SONG ; Jinyoung LEE ; Young Woo GONG ; Mun Ju KWON ; Hyung Wook KWON ; Young Yil BAHK ; Tong-Soo KIM
The Korean Journal of Parasitology 2021;59(3):281-289
This study aimed to characterize the seasonal abundance of hard ticks that transmit severe fever with thrombocytopenia syndrome virus from April to November 2019 and 2020 on Ganghwa-do, Incheon Metropolitan City, Korea. The ticks were collected at grassland, grave site, copse and mountain road using a collection trap method. The ixodid hard ticks comprising three species (Haemaphysalis longicornis, H. flava, and Ixodes nipponensis) collected were 6,622 in 2019 and 3,811 in 2020. H. longicornis was the most frequent (97.9% in 2019 and 96.0% in 2020), followed by H. flava (2.0% and 3.0% in 2019 and 2020, respectively) and I. nipponensis (less than 0.1%). Our study demonstrated that seasonal patterns of the tick populations examined for two years were totally unsimilar. The hard ticks tested using RT-qPCR were all negative for severe fever with thrombocytopenia syndrome virus.
4.Effect of investment materials on 3-point flexural strength of heat pressed zirconia core
Tae-Yeon KIM ; Seha KIM ; Jeong-Hui JI ; Byoung gu LIM ; Sung Geun OH ; Jaewoo SHIN ; Junghwan LEE ; Min-Ho LEE ; Tae-Sung BAE
Korean Journal of Dental Materials 2020;47(4):211-220
The purpose of this study was to evaluate the effect of the reaction between investment material and zirconia on the strength of zirconia in the application of heat-pressing method. Sixty specimens were cut (24 mm×4 mm×0.5 mm) into plates from Zirtooth ™ Multi O-9814 block (∅98×14T, HASS, Gangwondo, Korea) and sintered at 1450℃. Specimens were divided into 6 subgroups according to the depending on the investement material; (a) UN group (Control), (b) PH group (Prime vest HS), (c) CP group (Calibra-press), (d) BV group (BC-Vest), (e) MH group (Microstar-HS), (f) F1 group (Formula 1). Five investment materials were buried according to the procedure recommended by the manufacturer and left at room temperature for 30 minutes. The investment mold was dried and maintained at an elevated temperature of 850℃ for 50 minutes. Then, Amber Lisi-POZ LT (HASS) was placed in a thermoformed electric furnace (Programat EP3000/G2, Ivoclar Vivadent, Schaan, Liechtenstein) together with the mold, heated to 915℃ at an elevation temperature of 45℃/min, and moored for 15 minutes. The specimens were loaded to fracture in a universal testing machine and the fracture surface was examined by a field-emission scanning electron microscopy (FE-SEM). The surface of the zirconia specimen with the investment material was analyzed by energy dispersive X-ray spectroscopy (EDS). The 3-point flexural strength test showed the highest value (1265.5 MPa) in the UN group and the lowest value (756.1 MPa) in the F1 group. As a result of EDS analysis, the largest amount of Si was detected in the F1 group, and the most interfacial changes occurred as a result of FE-SEM analysis. It was concluded that when the zirconia is buried with the investment material and the heat press molding is performed, the state of the interface is changed due to the investment material at the bonding interface while the strength is lowered.
5.p38 MAPK Participates in Muscle-Specific RING Finger 1-Mediated Atrophy in Cast-Immobilized Rat Gastrocnemius Muscle.
Junghwan KIM ; Kyung Jong WON ; Hwan Myung LEE ; Byong Yong HWANG ; Young Min BAE ; Whan Soo CHOI ; Hyuk SONG ; Ki Won LIM ; Chang Kwon LEE ; Bokyung KIM
The Korean Journal of Physiology and Pharmacology 2009;13(6):491-496
Skeletal muscle atrophy is a common phenomenon during the prolonged muscle disuse caused by cast immobilization, extended aging states, bed rest, space flight, or other factors. However, the cellular mechanisms of the atrophic process are poorly understood. In this study, we investigated the involvement of mitogen-activated protein kinase (MAPK) in the expression of muscle-specific RING finger 1 (MuRF1) during atrophy of the rat gastrocnemius muscle. Histological analysis revealed that cast immobilization induced the atrophy of the gastrocnemius muscle, with diminution of muscle weight and cross-sectional area after 14 days. Cast immobilization significantly elevated the expression of MuRF1 and the phosphorylation of p38 MAPK. The starvation of L6 rat skeletal myoblasts under serum-free conditions induced the phosphorylation of p38 MAPK and the characteristics typical of cast-immobilized gastrocnemius muscle. The expression of MuRF1 was also elevated in serum-starved L6 myoblasts, but was significantly attenuated by SB203580, an inhibitor of p38 MAPK. Changes in the sizes of L6 myoblasts in response to starvation were also reversed by their transfection with MuRF1 small interfering RNA or treatment with SB203580. From these results, we suggest that the expression of MuRF1 in cast-immobilized atrophy is regulated by p38 MAPK in rat gastrocnemius muscles.
Aging
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Animals
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Atrophy
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Bed Rest
;
Fingers
;
Imidazoles
;
Immobilization
;
Muscle, Skeletal
;
Muscles
;
Myoblasts
;
Myoblasts, Skeletal
;
p38 Mitogen-Activated Protein Kinases
;
Phosphorylation
;
Protein Kinases
;
Pyridines
;
Rats
;
RNA, Small Interfering
;
Space Flight
;
Starvation
;
Transfection
6.Severe Liver Dysfunction after Donor Lymphocyte Infusion for Relapsed Multiple Myeloma
Tae-Hoon NO ; Nae-Yun HEO ; Seung Ha PARK ; Joon Hyuk CHOI ; Junghwan LEE ; Sung Nam LIM ; Seon Yang PARK
The Korean Journal of Gastroenterology 2024;83(3):123-126
Donor lymphocyte infusion (DLI) is performed to augment an anti-tumor immune response or ensure donor stem cells remain engrafted following allogeneic stem cell transplantation but may induce graft-versus-host disease (GVHD) involving skin, intestine, and liver. Although hepatic involvement of GVHD can manifest as mild to severe hepatitis, few reports have mentioned acute severe liver dysfunction with encephalopathy. We experienced a case of acute severe liver dysfunction with semicoma after DLI in a patient with relapsed multiple myeloma following allogeneic stem cell transplantation, in whom chronic viral hepatitis B had been suppressed by antiviral treatment. The patient recovered after high-dose glucocorticoid administration based on an assessment of hepatic GVHD.Clinicians should be aware of the possibility of this catastrophic hepatic complication after DLI in hematologic disorders.