1.MECHANICAL PROPERTIES OF TITANIUM CONNECTORS TREATED BY VARIOUS WELDING TECHNIQUES.
Soo Young LEE ; Ik Tae CHANG ; Seong Joo HEO ; Soon Ho YIM
The Journal of Korean Academy of Prosthodontics 1999;37(5):545-566
The use of pure titanium and titanium alloys have been increased recently in fixed, removable prosthodontics and implant fields as a framework. But when they were used for superstructures of implant of metal framework of removable prosthesis, welding is necessary to reconnect the fracture site to control the casting distortions. To overcome the difficulties in soldering the titanium due to high oxidation property, much effort have been devoted. In this study, some of mechanical properties were compared between pure titanium and Ti-6Al-4V alloy by usingl aser welding, electron beam welding technique and tungsten arc welding. Mechanical properties such as tensile strength, yield strength, elongation and microhardness were measured. And, in order to compare the effect of welding site and surrounding metal tissue according to the welding condition, SEM photographs were taken an element distribution was observed by Wave Dispersion Spectroscopy. Through analyses of the data, following results were obtained; 1. In items such as tensile strength, yield strength and elongation according to the welding techniques of pure titanium, only tungsten arc welded group showed significant lower value than other groups(P<0.05). 2. In items such as tensile strength and yield strength according to the welding techniques of Ti-6Al-4V alloy, control group and tungsten arc welded group showed significant difference among all the groups(P<0.05). 3. Ti-6Al-4V alloy exhibited significantly greater elongation than control group when the laser welding method and electron beam welding method were used, and elongation showed increasing tendency. 4. Pure titanium specimens exhibited increasing tendency of microhardness regardless of the welding technique applied, and especially tungsten arc welded group demonstrated a great increase of microhardness than parent metal. 5. There was no hardness change in laser welded group and electron bean welded group of Ti-6Al-4V ally, but in tungsten arc welded group, hardness changed greatly from parent metal to weld seam. 6. Through the metallographic examination and scanning electron microscopy, laser welding caused central fusion and recristallizations were formed and tungsten arc welding caused localized fusion to 0.3-0.7mm from the surface.
Alloys
;
Hardness
;
Humans
;
Microscopy, Electron, Scanning
;
Parents
;
Prostheses and Implants
;
Prosthodontics
;
Spectrum Analysis
;
Tensile Strength
;
Titanium*
;
Tungsten
;
Welding*
2.Behavioral and psychological symptoms in Korean patients with mild Alzheimer’s disease: Preliminary study
Soo-Ji Lee ; Jae-Hyeok Heo ; Hee-Tae Kim ; Jin-Young Ahn
Neurology Asia 2013;18(1):65-71
Behavioral and psychological symptoms of dementia are major components of Alzheimer’s disease.
In this study, we aimed at investigating the prevalence and severity of behavioral and psychological
symptoms of dementia in very mild to mild Alzheimer’s disease. Forty-four patients with Alzheimer’s
disease who visited the neurology outpatient clinic of Seoul Medical Center were included. A trained
neurologist or a supervised test technician administered the neuropsychological test, the Seoul
Neuropsychological Screening Battery including Mini Mental State Examination and Clinical Dementia
Rating. The instrument used for assessing behavioral and psychological symptoms of dementia was
Neuropsychiatric Inventory-Questionnaire. In order of prevalence, apathy, depression, irritability,
anxiety, and agitation were the most common symptoms occurring in very mild-to-mild Alzheimer’s
disease group. The prevalence and severity of behavioral and psychological symptoms of dementia
were found to be in positive correlation with the Clinical Dementia Rating scores. Behavioral and
psychological symptoms of dementia are found even in the very early stage of Alzheimer’s disease,
apathy and depression being the most common symptoms. Physicians should be aware of this when
managing dementia patients.
3.Development of Smartphone Application That Aids Stroke Screening and Identifying Nearby Acute Stroke Care Hospitals.
Hyo Suk NAM ; Joonnyung HEO ; Jinkwon KIM ; Young Dae KIM ; Tae Jin SONG ; Eunjeong PARK ; Ji Hoe HEO
Yonsei Medical Journal 2014;55(1):25-29
PURPOSE: The benefits of thrombolytic treatment are time-dependent. We developed a smartphone application that aids stroke patient self-screening and hospital selection, and may also decrease hospital arrival time. MATERIALS AND METHODS: The application was developed for iPhone and Android smartphones. Map data for the application were adopted from the open map. For hospital registration, a web page (http://stroke119.org) was developed using PHP and MySQL. RESULTS: The Stroke 119 application includes a stroke screening tool and real-time information on nearby hospitals that provide thrombolytic treatment. It also provides information on stroke symptoms, thrombolytic treatment, and prescribed actions when stroke is suspected. The stroke screening tool was adopted from the Cincinnati Prehospital Stroke Scale and is displayed in a cartoon format. If the user taps a cartoon image that represents abnormal findings, a pop-up window shows that the user may be having a stroke, informs the user what to do, and directs the user to call emergency services. Information on nearby hospitals is provided in map and list views, incorporating proximity to the user's location using a Global Positioning System (a built-in function of smartphones). Users can search for a hospital according to specialty and treatment levels. We also developed a web page for hospitals to register in the system. Neurology training hospitals and hospitals that provide acute stroke care in Korea were invited to register. Seventy-seven hospitals had completed registration. CONCLUSION: This application may be useful for reducing hospital arrival times for thrombolytic candidates.
*Cellular Phone
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Geographic Information Systems
;
Hospitals
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Humans
;
Republic of Korea
;
Stroke/*diagnosis
4.Risk Factors of Unfavorable Outcomes, Major Bleeding, and All-Cause Mortality in Patients with Venous Thromboembolism
Han Young LEE ; Tae Hoon YEO ; Tae Kyung HEO ; Young Gyu CHO ; Dong Hui CHO ; Kyung Bok LEE
Vascular Specialist International 2021;37(4):46-
Purpose:
This study aimed to analyze the clinical outcomes of venous thromboembolism (VTE) patients and identify the risk factors for VTE-related unfavorable outcomes, major bleeding, and 30-day all-cause mortality.
Materials and Methods:
From January 2016 to December 2020, 198 patients with confirmed VTE were enrolled. Potential risk factors for unfavorable outcomes, major bleeding, and all-cause mortality were analyzed.
Results:
VTE-related unfavorable outcomes developed in 13.1%, while 30-day all-cause mortality was 8.6%. In the multivariate analysis, a pulse ≥110/min and respiratory rate ≥30/min were statistically significant predictors for VTE-related unfavorable outcomes. Diabetes was a significant risk factor for major bleeding. In addition, a history of malignancy, no anticoagulation treatment, and need for mechanical ventilation were significant predictors of all-cause mortality.
Conclusion
VTE-related mortality and morbidity rates remained high. In cases of tachycardia and tachypnea, early aggressive treatment is needed to prevent unfavorable outcomes. Patients with risk factors should be closely monitored.
5.Color stability of current prosthetic composites under accelerated aging and Immersion in a coffee solution.
Hyo Jin KIM ; Seong Joo HEO ; Jai Young KOAK ; Ik Tae CHANG
The Journal of Korean Academy of Prosthodontics 2002;40(3):225-235
The color stability of current prosthetic composites is unknown, even though the quality of com-posite materials has been improving. This study examined the intrinsic color stability of various current prosthetic resins (ceramic-polymers) after an accelerated aging process and the extrinsic color stability after immersion in a coffee solution. By comparing the amount of dis-coloration after aging with that without aging, the effect of the accelerated aging process on external discoloration could be evaluated. Three current prosthetic composites (Artglass, Targis, Sculpture), one light polymerized direct composite (Z100) and one dental porcelain control (Ceramco) were assessed. The col-or changes (delta E) of all the specimens were determined using the CIE L*a*b* color order system with a reflected spectrophotometer. The results were as follows: 1. The prosthetic composite materials subjected to the accelerated aging test showed no sig-nificant difference in color changes (p> .05). 2. In the coffee solution immersion test after the aging process, the color changes of the Targis and Artglass groups were not different from that of the Z100 group, which showed the highest color change. 3. In the immersion only test, a significantly high color change was observed in the sculpture glazing group. 4. The aging process influenced on the color changes more in the Targis, Artglass and Z100 groups than in the Sculpture and Ceramco groups.
Aging*
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Coffee*
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Dental Porcelain
;
Immersion*
;
Polymers
;
Sculpture
6.A STUDY ON THE STRESS DISTRIBUTION OF ABUTMENT TEETH AND RESIDUAL RIDGE AREA BETWEEN TELESCOPIC AND CLASP TYPE RPD BY FEM METHOD.
Jai Young KOAK ; Kwang Nam KIM ; IK Tae CHANG ; Seong Joo HEO
The Journal of Korean Academy of Prosthodontics 1999;37(1):104-126
The purpose of this study was to compare and evaluate the stress distribution and displacement developed in the abutment teeth and residual ridge area by madibular unilateral distal extension removable partial denture with 2 different retainer designs. The retainers on right and left canine and right 2nd molar were Akers clasp in one model and telescopic crown in the other model. The stress distribution of abutment teeth and residual ridge area on two model were compared and analyzed with 3-dimensional finite element method. 150N and 400N forces were applied vertically, 30 degree and horizontally on the central fossa area of left 1st molar of the removable partial denture, and then stress distribution patterns were analyzed and compared. The results were as follows 1. As the magnitude and angulation of applied force were increased, the magnitude of stress on the right and central residual ridge area and the right canine of the telescopic type increased and comparing to those of the Akers clasp type. 2. As the magnitude and angulation of applied force were increased, the mesial direction of displacement on the right residual ridge area and the right tooth of the telescopic type increased and the distal direction of displacement on left residual ridge area and the left canine increased comparing to those of Akers clasp type. 3. As the vertical force was applied, the distal direction of the displacement of the right tooth were greater and that of the left canine was smaller and the upward displacement of the right canine was greater in telescopic partial denture than those of Akers clasp type. 4. As the 30 degree force was applied, the mesial direction of the displacement of the right tooth were greater and the distal direction of the displacement of the left canine was smaller and the upward displacement of the right canine was greater in telescopic partial denture than those of Akers clasp type. In the horizontal force the results were same in right area tooth but the distal direction of displacement was greater in left canine. 5. In both removable partial dentures, as the magnitude and degree of force were increased, the stress and displacement were increased. The compressive force was dominative than the tensile force. 6. In both removable partial dentures, the magnitude of stress was greater on mucosal tissue area than that of the alveolar bone area on distal extension residual ridge area but the result was reversed on anterior residual ridge area. The displacement was always greater on mucosal tissue area than that of alveolar bone area.
Crowns
;
Denture, Partial
;
Denture, Partial, Removable
;
Molar
;
Mucous Membrane
;
Tooth*
7.Phase II study of 5-fluorouracil and recombinant interferon-gamma in patients with advanced colorectal cancer.
Heung Tae KIM ; Chang In SUH ; Si Young KIM ; Dae Seog HEO ; Yung Jue BANG ; Noe Kyeong KIM
Journal of the Korean Cancer Association 1992;24(5):743-758
No abstract available.
Colorectal Neoplasms*
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Fluorouracil*
;
Humans
;
Interferon-gamma*
8.The Programming of Chemotherapy Order System.
Jung Tae KIM ; Je Hwan LEE ; Hye Won HAN ; Young Seol HEO ; Yeong Man LEU ; Tae Won KIM ; Jung Shin LEE
Journal of Korean Society of Medical Informatics 1999;5(3):45-49
As a part of plan to construct a multifunctional hospital information system, We planned to develop a chemotherapy order system. First, a software developing team was established which is composed of hematooncology staffs, special pharmacists and programmer who are responsible for OCS. We set up an outline of this system after collecting various kinds of sources such as foreign examples, gathered protocol that are used for chemotherapy, and organized these protocol in programming the chemotherapy order system. This project is expected to provide accurate prescription, to shorten the time to prepare prescription, to standardize the protocol of chemotherapy within the medical center, to manage an effective dispensing schedule and to be used as a source for education and research.
Appointments and Schedules
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Drug Therapy*
;
Education
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Hospital Information Systems
;
Humans
;
Pharmacists
;
Prescriptions
9.Computed Tomography-Based Morphologic Analysis of Osteoarthritis of the Distal Radioulnar Joint Associated with Extensor Tendon Ruptures
Min-Gu JANG ; Youn Moo HEO ; Young Ki MIN ; Tae Gyun KIM ; Byung Hak OH ; Tae Hyeong KIM
Clinics in Orthopedic Surgery 2021;13(1):97-104
Background:
Although the scallop sign is considered the most important risk factor for extensor tendon ruptures (ETRs) in patients with osteoarthritis of the distal radioulnar joint (DRUJ), previous reports provide a limited understanding of the changes at DRUJ, as risk factors were examined in plain radiographs of the wrist. The aim of this study was to assess the changes of DRUJ using axial images of computed tomography (CT) in patients with DRUJ osteoarthritis and associated ETRs and to evaluate the relationship between the changes of DRUJ and ETRs.
Methods:
Twelve patients with ETRs due to osteoarthritis of the DRUJ were enrolled. The changes of DRUJ were examined on axial images of CT and the following 8 parameters were measured: width of radius, anteroposterior (AP) length of radius, width of sigmoid notch (SN), AP length of SN, AP length of ulnar head, subluxation length of ulnar head, dorsal inclination of SN, and distance from Lister’s tubercle to SN. Radiological parameters of the DRUJ were measured in 60 control wrists without trauma or osteoarthritis, and the patient and control groups were statistically compared.
Results:
Statistically significant differences were observed between the patient and control groups in all the radiological parameters except for the AP length of SN and AP length of ulnar head. The width of radius, AP length of radius, width of SN, subluxation length of ulnar head, and dorsal inclination of SN were greater and the distance from Lister’s tubercle to SN was smaller in the patient group than in the control group. The width of SN, dorsal inclination of SN, and distance from Lister’s tubercle to SN were statistically significant risk factors among the 8 parameters.
Conclusions
ETRs due to osteoarthritis of the DRUJ was related to the changes of DRUJ, especially the changes around SN of the distal radius. In addition to the existing risk factors, a decreased distance from Lister’s tubercle to SN and increased dorsal inclination of SN were identified as new risk factors. Axial images of CT were effective to evaluate degenerative changes at the DRUJ.
10.Seroprevalence of Hepatitis C Virus Infection in North Korean Defectors Residing in Korea
Young Mi HONG ; Ki Tae YOON ; Young Joo PARK ; Hyun Young WOO ; Jeong HEO
Journal of Korean Medical Science 2023;38(34):e270-
Background:
This study aimed to investigate the prevalence rate of hepatitis C virus (HCV) infection and identify the demographic, and sociological characteristics and changes in awareness of HCV infection by participating the study for North Korean defectors residing in South Korea.
Methods:
This study prospectively enrolled participants. Demographic, sociological and clinical data, and questionnaire surveys focused on awareness of HCV infection were collected.
Results:
In total, 211 North Korean defectors participated in this study from September 2020 until June 2021. There were 174 women (82.5%), and the overall mean age was 48.9 years (range, 20 to 80 years). Of these participants, 112 (53.1%) had immigrated to South Korea since 2011. The overall prevalence of anti-HCV antibody among North Korean defectors was 1.9%. Thirty participants (14.2%) had hepatitis B surface antigens. A huge lack of awareness regarding HCV infection has been observed among North Korean defectors.
Conclusion
This is the first prospective study to investigate the prevalence rate of HCV infection among North Korean defectors residing in South Korea. As North Korean defectors are a vulnerable group concerning HCV infection, they may benefit from HCV screening policies and educational interventions for HCV infection.