2.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.
3.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.
4.Development and Performance Evaluation of a Quantitative Reverse Transcription PCR Kit for the Determination of prohibitin Gene Expression
Bo-Ram NA ; Young-Eun LEE ; Min-Gu KANG ; Yonggwan WON ; Hye-Ran KIM ; Myung-Geun SHIN
Laboratory Medicine Online 2020;10(3):214-220
Background:
Prohibitin (PHB) regulates intracellular signal pathways, transcription, and cell cycles. Aberrant expression of the PHB gene is known to be related totumorigenesis, tumor progression, and chronic metabolic and inflammatory diseases. The present study aimed to develop a one-step quantitative reverse transcription PCR (RT-qPCR) kit for quantifying PHB mRNA levels and evaluate its performance in the laboratory.
Methods:
TaqMan chemistry was used to develop the one-step PHB1 and PHB2 RT-qPCR kit. Normal peripheral blood cells from healthy individuals (N=20) and leukemia cells from patients initially diagnosed with acute myeloid leukemia (AML, N=20), chronic myeloid leukemia (CML, N=13), and acute lymphoid leukemia (ALL, N=7) were enrolled to evaluate the laboratory performance of the kit using commercially available total human RNA controls.
Results:
The intra-assay and inter-assay precision of the kit developed in this study was less than 2%. The distribution of PHB1 mRNA expression of AML, CML, and ALL was 0.898-0.993 (median: 0.936), 0.817-0.976 (0.918), and 0.844-1.074 (0.973), respectively. The distribution of PHB2 mRNA expression of AML, CML, and ALL was 0.957-1.024 (median: 0.985), 0.988-1.047 (1.002), and 0.937-1.059 (1.004), respectively. The sensitivity, specificity, positive and negative predictive value, and test effectiveness of the developed PHB1 and PHB2 kit were greater than 50% for each parameter.
Conclusions
Our developed kit would be useful for diagnosing leukemia as well as detecting residual disease. Additionally, this kit could be used for monitoring and conducting molecular pathophysiological studies of obesity, metabolic, and inflammatory diseases.
5.Changing the frequency and spectra of chromosomal aberrations in Korean patients with acute leukemia in a tertiary care hospital
Je-Hyun PARK ; Min-Gu KANG ; Hye-Ran KIM ; Young-Eun LEE ; Jun Hyung LEE ; Hyun-Jung CHOI ; Jong-Hee SHIN ; Myung-Geun SHIN
Blood Research 2020;55(4):225-245
Background:
Chromosomal analysis is essential for the diagnosis and risk stratification of all leukemia patients. Not surprisingly, racial differences in chromosomal aberrations (CA) in hematological malignancies could be found, and CA incidence in leukemia might change over time, possibly due to environmental and lifestyle changes. Thus, we compared the frequency and range of CA in patients with acute leukemia (AL) during two time periods (2006‒2009 vs. 2010‒2015) and compared them with other prior studies.
Methods:
We enrolled 717 patients with AL during a six-year period (2010‒2015). We compared the results to those of our earlier study (2006‒2009) [1]. Conventional cytogenetics, a multiplex reverse transcriptase (RT)-PCR system, and fluorescence in situ hybridization were employed to assess bone marrow specimens or peripheral blood at the diagnostic stage in AL patients to detect CA.
Results:
The incidence of CA changed in the leukemia subgroups during the two time periods.Notably, the most frequent CA of childhood acute myeloid leukemia (AML) was PML/RARA, and was followed by RUNX1/RUNX1T1 in the current study. In contrast, the most common CA was RUNX1/RUNX1T1 in a previous study [1] and was followed by PML/RARA. In this study, the most frequent CA of the mixed phenotype AL was BCR/ABL1, which was followed by KMT2A/MLLT3. In a previous report, [1] the most frequent CA was BCR/ABL1, which was followed by KMT2A/ELL.
Conclusion
The distribution of CA in Korean AL patients changed over time in a single institute. This change might be due to environmental and lifestyle changes.
7.Fluoranthene-Induced Cytotoxicity and Direct Effect of Aryl Hydrocarbon Receptor Antagonist on Hematopoietic Stem Cell Differentiation
Seung Hyun YANG ; Min Gu KANG ; Hye Ran KIM ; Young Eun LEE ; Bo Ram NA ; Jun Hyung LEE ; Jong Hee SHIN ; Myung Geun SHIN
Annals of Laboratory Medicine 2019;39(6):580-583
No abstract available.
Hematopoietic Stem Cells
;
Receptors, Aryl Hydrocarbon
8.Study on Assessment and Treatment Patterns of Speech-Language Pathologists in Pediatric Vocal Problem Through Multicenter Survey
Jong Geun LEE ; Seung Hwan BANG ; Jae Min JEON ; Jung Kyu LEE ; Angela Yun KIM ; Jeong Soo WOO ; Jae Gu CHO
Journal of the Korean Society of Laryngology Phoniatrics and Logopedics 2019;30(1):39-47
BACKGROUND AND OBJECTIVES: Pediatric vocal health problems are relatively common. However, it is not yet well studied whether uniform diagnosis and treatment is done properly in South Korea. The purpose of this study was to investigate the methods that the Korean speech therapists use to diagnose and treat pediatric voice problem. MATERIALS AND METHOD: An anonymous online questionnaire was administered to 32 speech language therapists registered at the Korean laryngeal speech linguistics society detailing demographics, employment institution, general management of pediatric patients with vocal problem including assessment and treatment procedures. RESULTS: Current practice patterns were analyzed on 32 speech language therapists providing services in South Korea mostly working at tertiary university hospital. One third of pediatric patients were assessed without proceeding to treatment. One fifth of patients were treated without assessment. Perceptual assessment was the main pre-treatment assessment methods used. Treatment was done in the following order : Voice rest, SOVT, yawn-sigh and resonant voice. Post-treatment evaluation was used in the following order : Instrumental assessment, clinical judgment, and recording comparison. CONCLUSION: Speech language therapists practice in South Korea mostly follows the ASHA practice guidelines. However, there are still great amount of cases in which only the evaluation was done without appropriate treatment. Further research is needed to make SPLs more systematic and efficient for evaluating and treating pediatric vocal patients.
Anonyms and Pseudonyms
;
Clothing
;
Demography
;
Diagnosis
;
Employment
;
Humans
;
Judgment
;
Korea
;
Linguistics
;
Methods
;
Voice
9.Comparison of work-related musculoskeletal symptoms between male cameramen and male office workers
Han Seur JEONG ; Byung Seong SUH ; Soo Geun KIM ; Won Sool KIM ; Won Cheol LEE ; Kyung Hun SON ; Min Woo NAM
Annals of Occupational and Environmental Medicine 2018;30(1):28-
BACKGROUND: Previous studies have classified cameramen’s job as physiologically heavy work and identified the risk factors of work-related musculoskeletal disorders (WRMDs) in cameramen. However, those studies limited their research subjects to cameramen. In this study, we compared the frequency and severity of WRMDs between cameramen and office workers. METHODS: A total of 293 subjects working in four broadcasting companies in Korea were recruited. A questionnaire survey was conducted for a month, starting in October 2016. The subjects were divided into cameramen and office workers according to their occupation. We compared the frequency and severity of WRMDs and ergonomic risk assessment results between the two groups. RESULTS: The high-risk WRMD group had a higher proportion of cameramen than office workers. Moreover, the high ergonomic risk group also had a higher proportion of cameramen than office workers for WRMDs in the upper extremities and waist+lower extremities. In the multivariable-adjusted model comparing cameramen and office workers, the odds ratio (OR) with 95% confidence interval (95% CI) for high-risk WRMDs was 3.50 (95% CI: 1.92–7.72) for the upper extremities and 3.18 (95% CI: 1.62–6.21) for the waist and the lower extremities. The ORs by body parts were 3.11 (95% CI: 1.28–7.57) for the neck, 3.90 (95% CI: 1.79–8.47) for the shoulders, and 4.23 (95% CI: 1.04–17.18) for the legs and feet. CONCLUSIONS: Our study suggests that cameramen are at high risk of WRMDs. Workplace improvements and management of the neck, shoulders, and lower extremities, which are susceptible to WRMDs, are necessary to prevent musculoskeletal disorders among cameramen.
Extremities
;
Foot
;
Human Body
;
Human Engineering
;
Humans
;
Korea
;
Leg
;
Lower Extremity
;
Male
;
Neck
;
Occupations
;
Odds Ratio
;
Research Subjects
;
Risk Assessment
;
Risk Factors
;
Shoulder
;
Upper Extremity
10.Electroconvulsive Seizure Alters the Expression and Daily Oscillation of Circadian Genes in the Rat Frontal Cortex.
Se Hyun KIM ; Hong Geun PARK ; Seong Hoon JEONG ; Ung Gu KANG ; Yong Min AHN ; Yong Sik KIM
Psychiatry Investigation 2018;15(7):717-726
OBJECTIVE: Electroconvulsive therapy (ECT) is the most effective treatment for mood disorders. Accumulating evidence has suggested the important role of circadian genes in mood disorders. However, the effects of ECT on circadian genes have not been systemically investigated. METHODS: We examined the expression and daily oscillation of major circadian genes in the rat frontal cortex after electroconvulsive seizure (ECS). RESULTS: Firstly, mRNA and protein level were investigated at 24 hr after single ECS (E1X) and repeated ECS treatements for 10 days (E10X), which showed more remarkable changes after E10X than E1X. mRNA expression of Rorα, Bmal1, Clock, Per1, and Cry1 was decreased, while Rev-erbα expression was increased at 24 hr after E10X compared to sham. The proteins showed similar pattern of changes. Next, the effects on oscillation and rhythm properties (mesor, amplitude, and acrophase) were examined, which also showed more prominent changes after E10X than E1X. After E10X, mesor of Rorα, Bmal1, and Cry1 was reduced, and that of Rev-erbα was increased. Five genes, Rev-erbα, Bmal1, Per1, Per2, and Cry2, showed earlier acrophase after E10X. CONCLUSION: The findings suggest that repeated ECS induces reduced expression and phase advance of major circadian genes in the in vivo rat frontal cortex.
Animals
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Circadian Rhythm
;
Electroconvulsive Therapy
;
Frontal Lobe*
;
Mood Disorders
;
Rats*
;
RNA, Messenger
;
Seizures*

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