1.The effect of heat treatment of the TI6AL4V specimen fabricated by selective laser melting method on the crystalline structure and chemical compositions
Ho-Jun SONG ; Yeong-Joon PARK ; Won-Jin MOON ; Wan-Gil JUNG ; Seon-Shin CHO ; Byeong-Mo KANG ; Taek-Rim YOON
Korean Journal of Dental Materials 2023;50(2):99-108
In this study, the Ti6Al4V specimens were fabricated using selective laser melting (SLM) method (Ti6Al4V-AS group). These specimens were performed to heat treatment at 950℃ and 550℃ using vacuum electric furnace (Ti6Al4V-HT group). The mechanical properties, metallographic shape, crystalline structure, and chemical compositions of the alloy specimens before and after heat treatment were analyzed. The Ti6Al4V-AS group showed ultimate tensile strength (UTS) and low elongation values. Acicular crystal grains were observed in metallographic image and the α'-Ti phase was dominant. After heat treatment (Ti6Al4V-HT group), the UTS was lowered and the elongation was increased. In addition, a lamellar structure in which columnar crystal grains are arranged was observed, α+β-Ti phase was formed, and crystallinity increased. As a result of analyzing the chemical composition, the Ti6Al4V-AS specimen contained a higher carbon content than the Ti6Al4V-HT specimen. This high carbon content could be related to the formation of α'-phase, high strength and low elongation of the Ti6Al4V-AS specimen. Ti6Al4V-HT specimen showed that the overall carbon content was low, but the carbon content was locally high in the α-Ti phase region. Therefore, it is necessary to control effectively the incorporation of carbon gas in the production of Ti6Al4V specimens using SLM.
2.Fates of retained hepatic segment IV and its prognostic impact in adult split liver transplantation using an extended right liver graft
Yong-Kyu CHUNG ; Shin HWANG ; Chul-Soo AHN ; Ki-Hun KIM ; Deok-Bog MOON ; Tae-Yong HA ; Gi-Won SONG ; Dong-Hwan JUNG ; Gil-Chun PARK ; Young-In YOON ; Woo-Hyoung KANG ; Hwui-Dong CHO ; Jin Uk CHOI ; Minjae KIM ; Sang Hoon KIM ; Byeong-Gon NA ; Sung-Gyu LEE
Annals of Surgical Treatment and Research 2021;101(1):37-48
Purpose:
When splitting a liver for adult and pediatric graft recipients, the retained left medial section (S4) will undergo ischemic necrosis and the right trisection graft becomes an extended right liver (ERL) graft. We investigated the fates of the retained S4 and its prognostic impact in adult split liver transplantation (SLT) using an ERL graft.
Methods:
This was a retrospective analysis of 25 adult SLT recipients who received split ERL grafts.
Results:
The mean model for end-stage liver disease (MELD) score was 27.3 ± 10.9 and graft-recipient weight ratio (GRWR) was 1.98 ± 0.44. The mean donor age was 26.5 ± 7.7 years. The split ERL graft weight was 1,181.5 ± 252.8 g, which resulted in a mean GRWR of 1.98 ± 0.44. Computed tomography of the retained S4 parenchyma revealed small ischemic necrosis in 16 patients (64.0%) and large ischemic necrosis in the remaining 9 patients (36.0%). No S4-associated biliary complications were developed. The mean GRWR was 1.87 ± 0.43 in the 9 patients with large ischemic necrosis and 2.10 ± 0.44 in the 15 cases with small ischemic necrosis (P = 0.283). The retained S4 parenchyma showed gradual atrophy on follow-up imaging studies. The amount of S4 ischemic necrosis was not associated with graft (P = 0.592) or patient (P = 0.243) survival. A MELD score of >30 and pretransplant ventilator support were associated with inferior outcomes.
Conclusion
The amount of S4 ischemic necrosis is not a prognostic factor in adult SLT recipients, probably due to a sufficiently large GRWR.
3.Fates of retained hepatic segment IV and its prognostic impact in adult split liver transplantation using an extended right liver graft
Yong-Kyu CHUNG ; Shin HWANG ; Chul-Soo AHN ; Ki-Hun KIM ; Deok-Bog MOON ; Tae-Yong HA ; Gi-Won SONG ; Dong-Hwan JUNG ; Gil-Chun PARK ; Young-In YOON ; Woo-Hyoung KANG ; Hwui-Dong CHO ; Jin Uk CHOI ; Minjae KIM ; Sang Hoon KIM ; Byeong-Gon NA ; Sung-Gyu LEE
Annals of Surgical Treatment and Research 2021;101(1):37-48
Purpose:
When splitting a liver for adult and pediatric graft recipients, the retained left medial section (S4) will undergo ischemic necrosis and the right trisection graft becomes an extended right liver (ERL) graft. We investigated the fates of the retained S4 and its prognostic impact in adult split liver transplantation (SLT) using an ERL graft.
Methods:
This was a retrospective analysis of 25 adult SLT recipients who received split ERL grafts.
Results:
The mean model for end-stage liver disease (MELD) score was 27.3 ± 10.9 and graft-recipient weight ratio (GRWR) was 1.98 ± 0.44. The mean donor age was 26.5 ± 7.7 years. The split ERL graft weight was 1,181.5 ± 252.8 g, which resulted in a mean GRWR of 1.98 ± 0.44. Computed tomography of the retained S4 parenchyma revealed small ischemic necrosis in 16 patients (64.0%) and large ischemic necrosis in the remaining 9 patients (36.0%). No S4-associated biliary complications were developed. The mean GRWR was 1.87 ± 0.43 in the 9 patients with large ischemic necrosis and 2.10 ± 0.44 in the 15 cases with small ischemic necrosis (P = 0.283). The retained S4 parenchyma showed gradual atrophy on follow-up imaging studies. The amount of S4 ischemic necrosis was not associated with graft (P = 0.592) or patient (P = 0.243) survival. A MELD score of >30 and pretransplant ventilator support were associated with inferior outcomes.
Conclusion
The amount of S4 ischemic necrosis is not a prognostic factor in adult SLT recipients, probably due to a sufficiently large GRWR.
4.Prognosis of Split Liver Transplantation Compared with Whole Liver Transplantation in Adult Patients:Single-center Results under the Korean MELD Score-based Allocation Policy
Gil-Chun PARK ; Shin HWANG ; Gi-Won SONG ; Dong-Hwan JUNG ; Tae-Yong HA ; Chul-Soo AHN ; Deok-Bog MOON ; Ki-Hun KIM ; Young-In YOON ; Woo-Hyoung KANG ; Hwui-Dong CHO ; Jin Uk CHOI ; Minjae KIM ; Byeong-Gon NA ; Sang Hoon KIM ; Sung-Gyu LEE
Journal of Korean Medical Science 2020;35(37):e304-
Background:
Split liver transplantation (SLT) has been occasionally performed in Korea. This study compared the incidence and prognosis of SLT with whole liver transplantation (WLT) in adult patients.
Methods:
Between June 2016 and November 2019, 242 adult patients underwent a total of 256 deceased donor liver transplantation operations. SLT was performed in 7 patients (2.9%).
Results:
The mean age of SLT donors was 29.7 ± 7.4 years, and the mean age of recipients was 55.7 ± 10.6 years, with the latter having a mean model for end-stage liver disease score of 34.6 ± 3.1. Mean split right liver graft weight was 1,228.6 ± 149.7 g and mean graft-recipient weight ratio was 1.97 ± 0.39. Of the seven SLT recipients, Korean Network for Organ Sharing (KONOS) status was one in status 1, one in status 2 and five in status 3. The graft (p = 0.72) and patient (p = 0.84) survival rates were comparable in the SLT and WLT groups. Following propensity score matching, graft (p = 0.61) and patient (p = 0.91) survival rates remained comparable in the two groups. Univariate analysis showed that pretransplant ventilator support and renal replacement therapy were significantly associated with patient survival, whereas KONOS status category and primary liver diseases were not. Multivariate analysis showed that pretransplant ventilator support was an independent risk factor for patient survival.
Conclusion
Survival outcomes were similar in adult SLT and WLT recipients, probably due to selection of high-quality grafts and low-risk recipients. Prudent selection of donors and adult recipients for SLT may expand the liver graft pool for pediatric patients without affecting outcomes in adults undergoing SLT.
5.Efficacy of Cognitive Health Promotion Workbook for Community-Dwelling Elderlies with Mild Cognitive Impairment or Dementia Performed by Trained Dementia Partners
Hyun Ju YOU ; Seon Kyung YUN ; Byeong Kil YEON ; Jae Myeong KANG
Journal of Korean Geriatric Psychiatry 2019;23(1):6-13
OBJECTIVE: The aim of this study is to assess the efficacy of cognitive health promotion workbook for community-dwelling elderlies with mild cognitive impairment and dementia performed by trained dementia partners. METHODS: The trained dementia partners performed cognitive training program with the workbook developed by Incheon Metropolitan Dementia Center to 36 participants with mild cognitive impairment or dementia at their home. The cognitive training program consisted of 60-minute sessions held twice weekly for 10 weeks. We evaluated their cognitive performances at baseline and after intervention. Pre- and post-intervention measures included Korean version of Mini-Mental Status Examination for Dementia Screening (MMSE-DS), Global Deterioration Scale, Korea Activities of Daily Living Scale, Korea Instrumental Activities of Daily Living Scale, Korean Version of Short Form Geriatric Depression Scale (SGDS-K) and Korean Quality of Life-Alzheimer's Disease (KQoL-AD). RESULTS: Participants showed significant improvements compared with their baseline in MMSE-DS (p=0.002), SGDS-K (p=0.001) and KQoL-AD (p<0.001). There were no significant differences of improvement between high cognitive function group (MMSE ≤20, n=16) and low cognitive function group (MMSE ≤20, n=20). CONCLUSION: These findings suggest that the cognitive training program with cognitive health promotion workbook can improve cognitive function, quality of life and depression for community-dwelling elderlies with mild cognitive impairment and dementia and it would be efficient that trained dementia partners perform the cognitive training program regularly at their home.
Activities of Daily Living
;
Cognition
;
Dementia
;
Depression
;
Education
;
Health Promotion
;
Incheon
;
Korea
;
Mass Screening
;
Mild Cognitive Impairment
;
Quality of Life
6.Comparative Study of the Effects of Supportive Educational Programs : for Family Caregivers of the Elderly with Dementia.
Heup SONG ; Jae Myeong KANG ; Steven B KIM ; Seong Jin CHO ; Seonkyung YUN ; Hyejin YOON ; Byeong Kil YEON
Journal of Korean Geriatric Psychiatry 2017;21(1):17-28
OBJECTIVE: We studied the effect of Hyu-Sig-Gong-Gan and Hye-Ah-Rim on several evaluations and compared the two programs. We then investigated factors associated with the difference between pre- and post-ratings. METHODS: Thirty-six patients were randomized to Hyu-Sig-Gong-Gan (n=23) or Hye-Ah-Rim (n=13). We tested for the effect of each program on several evaluations and compared the two programs through Zarit Burden Interview (ZBI), Center for Epidemiologic Studies-Depression Scale, Dementia Attitude Scale (DAS)-intelligence, DAS-comfort and DAS-total. We then investigated whether the difference between pre- and post-rating depends on other factors. RESULTS: We observed significant positive effect of Hyu-Sig-Gong-Gan on DAS-comfort (t=1.843, p=0.039) and significant positive effect of Hye-Ah-Rim on ZBI (t=-2.327, p=0.019), DAS-comfort (t=2.241, p=0.022), and EuroQol-5 Dimensions-Visual Analogue Scale (t=2.537, p=0.013). For comparing the two programs, we found a lack of evidence for the difference in any of the five commonly observed evaluations. In the secondary analysis, we observed a strong trend that the two programs were particularly effective for caregivers with negative pre-ratings. CONCLUSION: The two programs showed positive effects on the various evaluations, but some evaluations could not reach statistical significance. The programs appear to be particularly helpful for those who are in need before the program participation.
Aged*
;
Caregivers*
;
Dementia*
;
Humans
;
Program Evaluation
7.Dementia Care by Healthy Elderly Caregivers Is Associated with Improvement of Patients' Memory and the Caregivers' Quality of Life: A Before and After Study.
Seung Gul KANG ; Kyoung Sae NA ; Jae Myeong KANG ; Byeong Kil YEON ; Jun Young LEE ; Seong Jin CHO
Psychiatry Investigation 2017;14(4):458-462
OBJECTIVE: The provision of care for elderly people with dementia by healthy elderly caregivers is one of the new health-care paradigms in South Korea. The aim of this study was to determine whether this type of care, which includes cognitive stimulation, would improve the cognitive function of dementia patients and the quality of life of the healthy elderly caregiver. METHODS: Totals of 132 dementia patients and 197 healthy elderly caregivers participated in this study. We evaluated the cognitive function of the dementia patients at baseline and after providing the program for 6 months using the Korean version of the Consortium to Establish a Registry for Alzheimer's disease, 1st Edition (CERAD-K). We also evaluated the quality of life of the healthy elderly caregivers using the World Health Organization Quality of Life-Short Version (WHOQOL-BREF) at baseline and after 6 months. RESULTS: The word-list memory results of CERAD-K for the included dementia patients improved after 6 months (Z=-2.855, p=0.004). The WHOQOL-BREF score among the elderly caregiver also improved significantly (Z=-2.354, p=0.019). CONCLUSION: These data suggest that dementia care is associated with improvements in both the cognitive function of dementia patients and the quality of life of the healthy elderly caregivers.
Aged*
;
Alzheimer Disease
;
Caregivers*
;
Cognition
;
Dementia*
;
Humans
;
Korea
;
Memory*
;
Quality of Life*
;
World Health Organization
8.Accuracy of the CT guided implant template by using an intraoral scanner according to the edentulous distance.
Byeong Gil KANG ; Hee Jung KIM ; Chae Heon CHUNG
The Journal of Korean Academy of Prosthodontics 2017;55(1):1-8
PURPOSE: The purpose of this study is to compare the accuracy of the CT guided implant template that was produced by using an intraoral scanner according to the edentulous distance. MATERIALS AND METHODS: Five maxillary casts were fabricated using radiopaque acrylic resin with the second premolars, first molars, and second molars missing. Then a virtual cast was acquired by scanning each resin cast. Implant treatment was planned on the missing sites by superimposing the presurgical CT DICOM file and the virtual cast. Then the implants were placed using a surgical template followed by postsurgical CT scan. The distance and angle of the platform and apex between the presurgical implant and postsurgical implant were measured using the X, Y, and Z axis of the superimposed presurgical CT and postsurgical CT via software followed by statistical analysis using Kruskall-Wallis test and Mann-Whitney test. RESULTS: The implant placement angle error increased towards the second molars but there was no statistically significant difference. The implant placement distance error at the platform and apex also increased towards the second molars and there was a statistically significant error at the second molars. CONCLUSION: Although the placement angle had no statistically significant difference between the presurgical implant and postsurgical implant, the placement distance at the platform and apex showed a larger error and a statistically significant difference at the second molar implant.
Bicuspid
;
Molar
;
Tomography, X-Ray Computed
9.Implant prosthesis using intraoral scanner: Case Report.
Byeong Gil KANG ; Hee Jung KIM ; Chae Heon CHUNG
The Journal of Korean Academy of Prosthodontics 2015;53(3):256-261
Accuracy is the most important thing in implant prosthesis, for this reason it is essential procedure to check the accuracy of impression taking. However, impression material has its own error and the error occurs in model-making procedure. As an alternative way to this, using intraoral scanner can be suggested and many studies were issued reporting that there's no statistically significant difference in accuracy between intraoral scanner and conventional impression. Therefore, the purpose of this study is to report the process of making of implant prosthesis using intraoral scanner, which is more convenient, fast, accurate compared with conventional method.
Prostheses and Implants*
10.Pneumatosis Cystoides Intestinalis with Pneumoperitoneum Complicating Systemic Sclerosis: A Case Report.
Jae Uk IM ; Eun Hye KIM ; Hong Gil JUN ; Ji Seon OH ; Seung Won CHOI ; Byeong Seong KANG
Korean Journal of Medicine 2013;84(6):868-872
The gastrointestinal tract is commonly involved in patients with systemic sclerosis. The manifestations include motility disorder, pseudo-obstruction, malabsorption, bacterial overgrowth, diverticuli, and, less commonly, pneumatosis cystoides intestinalis (PCI). PCI is characterized by the presence of air in the submucosal or subserosal layer of the bowel wall and is often accompanied by pneumoperitoneum. Although PCI is a benign condition that often responds to conservative management, it is a poor prognostic factor of systemic sclerosis. We report a case of PCI in a patient with systemic sclerosis. The chest and abdominal radiographic findings comprised pneumoperitoneum, marked dilation of the bowels, and intramural air, compatible with PCI. The patient's symptoms improved spontaneously. It is important to recognize PCI as a gastrointestinal manifestation of systemic sclerosis, and physicians should differentiate it from serious complications-such as intestinal perforation-based on clinical manifestations.
Gastrointestinal Tract
;
Humans
;
Pneumatosis Cystoides Intestinalis
;
Pneumoperitoneum
;
Scleroderma, Systemic
;
Thorax

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