Styrene과 2-Hydroxypropylacrylate(2-HPA) 공중합 특성

박근호,정영언,김남석,설수덕,서영옥 東亞大學校 大學院 1999 大學院論文集 Vol.24 No.-

Solution copolymerization of Styrene(St.) with 2-Hydroxypropylacrylate(2-HPA) was carried out with Benzoylperoxide(BPO) as an initiator in toluene at 80℃ in a batch reactor. Reaction volume and reaction time were 0.3 liters, 7hours respectively. The time to reach steady state was about the six time. The monomer reactivity ratios, r1(St.) and r2(2HPS) were determined by both the Kelen-Tudos method and the Fineman-Ross method : r1(St.)=0.376(0.330), r2(2-HPA)=0.408(0.778). The activation energy of thermal decomposition was in range of 33∼55 kcal/mol.

노인틀니 보험급여를 위한 건강보험재정추계연구

권호근,김영남,정기호,송근배,박덕영 대한구강보건학회 2003 大韓口腔保健學會誌 Vol.27 No.3

The purpose of this study is to estimate the National Health Insurance budget needed for the Korean elderly's denture service coverage. For more exact estimating the budget, denture need and demand were calculated by using 2000 National Oral Health Survey data. The results were summarized as follows ; 1. Over 65 years old, full denture and partial denture need per arch were each 8.5% and 16.8%. And over 70 years old, those were each 11.3% and 17.8%. 2. Over 65 years old, full denture and partial denture demand per arch were each 22.8% and 21.2%. And over 70 years old, those were each 27.%% and 21.1%. 3. Based on the denture need, the health insurance budget needed in the first operative year was about 955.4 billion won, over 65 years old and about 644.2 billion won, over 70 years old. 4. Based on the denture demand(wear), the health insurance budget needed in the first operative year was about 207.5 billion won, over 65 years old and was about 151.6 billion won, over 70 years old. If health insurance policy of elderly's denture service coverage is performed, actual denture wear rate is going to increase, and the budget needed is also increasing. Because current National Health Insurance budget status is poor, it is difficult to execute health insurance coverage for elderly's denture service. Therefore we suggest that health insurance coverage for preventive service is to be considered in order to reducing denture need in the long term view.

초내식성 스테인리스강 선재와 브라켓의 내식성 및 금속 이온 용출 특성

오근택,정경진,황충주,박용수,김경남 大韓齒科器材學會 2001 대한치과재료학회지 Vol.28 No.4

Metallic orthodontic appliances are known to release metal ions in an oral cavity. It is not advisable that toxic corrosion products derived from the appliances is absorbed into the body. Metal ions release from orthodontic appliances is known to have large effects on the result of orthodontic treatment and systemic health. Metal bracket and wire were made of super stainless steel(S32050) with high corrosion resistance. The corrosion resistance and ion release property of S32050 and conventionally used appliances were examined. Four types of wire were ligated in either super stainless steel(SB) or Tomy bracket(TB) with O-ring, and then each group was immersed in an artificial saliva at 37℃ for 12 weeks. Amount of released metal ions was measured with immersion time by graphite furnace atomic absorption spectroscopy and surface morphology was investigated. S32050 showed the low passive current density of about 1 μA/㎠ and the stable passive region to a high potential in artificial saliva. S32050 appliances did hardly release nickel ions in artificial saliva. S32050 wire(SRW) and NiTi wire(NW) didn't show significant difference of Ni ion release with immersion time, meanwhile, Remanium wire(RW) showed significant difference in 12 weeks. Ni ion releasce from the brackets didn't show any significant difference with immersion time and between SB and TB. Amounts of Ni ion released from TB-SRW showed significant difference in 12 weeks, those from TB-RW showed significant difference from 4 weeks later and highest release among all groupsin12weeks. TB-NW released little Ni ion for all immersion time and showed significant difference from 4 weeks later, TB-TW(TMA wire) showed significant difference in 12 weks. SB-SRW didn't show any significant difference and SB-RW signigicant difference in 12 weeks,but lower compared with TB group. SB-NW and SB-TW didn't show any significant difference. Corrosion products didn't be observed in mostly groups during the immersion time, except that in TB-RW, they were observed on the bracket surface between O-ring and wire from 8 weeks later. Super stainless steel wire had good corrosion resistance compared with stainless steel wire, and it is believed that it can be used as orthodontic material for bracket and wire.

교정학적 적용을 위한 초내식성 스테인리스강의 특성

오근택,김금진,황충주,박용수,김경남 大韓齒科器材學會 2001 대한치과재료학회지 Vol.28 No.3

Various kinds of orthodontic appliances have been developed for ideal tooth movement during orthodontic treatment. The orthodontic appliances made of metals are bands, arch wires, brackets and miniscrews as orthodontic anchorage. Generally, these appliances are made of stainless steel, pure titanium, Ni-Ti and TMA with the proper biocompatibility. However, localized corrosion of these materials can frequently occur in the particular environment. Super stainless steels, recently developed, have good corrosion resistance to reduce metal ion release induced by many kinds of corrosion. Recently, it has been reported that nickel ion release from orthodontic appliances affect the prevalence of nickel sensitization; however, there has been some controversy about nickel hypersensitivity to orthodontic appliances containing nickel. The purpose of this study was to evaluate and compare the microhardness, nickel ion release, corrosion resistance and cytotoxicity of 4 types of super stainless steels and 316L stainless steel as the control group according to nickel contents, and to determine the acceptability as the new material for various kinds of orthodontic appliances. All super stainless steels showed higher microhardness than 316L stainless steel, SR-3Mo showed especially the highest microhardness. In anodic polarization test, corrosion resistance was high in order of SR-50A, SFSS, SR-6DX, 316L stainless steel, SR-3Mo. There was no increase in nickel ion release from SR-50A, SR-6DX, 316L stainless steel with immersion time in artificial saliva; whereas there was some increase from SFSS and SR-3Mo with immersion time. All super stainless steels showed very low cytotoxicity regardless of nickel contents although SR-3Mo showed relatively higher cytotoxicity than the others. It is concluded that SR-50A among super stainless steels has the highest corrosion resistance and biocompatibility. It is undesirable to consider the alloys with high nickel content to release lots of nickel ion.

치과 재료용 NiTi 합금의 특성에 대한 Ag 첨가의 영향

오근택,박기호,심형민,황충주,김경남 大韓齒科器材學會 2001 대한치과재료학회지 Vol.28 No.4

Equiatomic and near-equiatomic nickel-titanium alloys have shape memory effect and superelasticity. However nickel-titanium alloys are extremely sensitive to the precise nickel-titanium ratio and alloying additions. There are many reports on the alloying additions such as Fe, Al, Cr, Co, V, Pt, Pd, Zr, Hf, Nb and Cu. The purpose of this study was to investigate the effect of silver addition to nickel-titanium alloy for dental and medical application.Arc melting process was used to fabricate nickel-titanium alloys. The casts were heat-treated in a vacuum furnace at 950℃ for 72 hours to homogenize their composition. Subsequently, they were hot-rolled at 950℃ to obtain the plate samples and annealed in a vacuum furnace at 950℃. To investigate the properties of nickel-titanium alloys, phases, transformation temperature, compositions, corrosion resistance and hardness were evaluated using X-ray diffractometer, differential scanning calorimeter, energy dispersive spectroscopy or atomic absorption spectroscopy, potentiostat and micro-vickers hardness tester, respectively. NiTiAg alloys showed the low silver recovery rate for the cast due to its low evaporation temperature, and showed low silver solubility to NiTi alloy. Silver addition to NiTi alloy increased transition temperature range (TTR) above 100℃ and stabilized martensitic phase(monoclinic structure) at room temperature because Ms temperature was above room temperature. Martensitic and austenitic phase existed in x-ray diffraction pattern of solution annealed NiTiAg alloys. The Silver addition is considered to improve corrosion resistance and change largely the mechanical properties depending upon the amount of alloying addition and types of addition elements.

거대적아구성빈혈의 임상적 고찰

곽승근,천재민,박남숙,박상은,박수진,윤환중,김삼용,조덕연 충남대학교 의학연구소 2003 충남의대잡지 Vol.30 No.2

Megaloblastic anemias are disorders caused by impaired DNA synthesis and chara-cterized by the presence of megaloblastic cells. Clinical data on these disorders in Korea are limited. The aim of this study was to analyze clinical characteristics of megaloblastic anemias caused by vitamin B12 deficiency. We identified 40 cases who were diagnosed as megaloblastic anemia from January 1993 to December 2002 in a retrospective study on the basis of chart review. We investigated the annual distribution of diagnosed patients, clinical manifestations and response to treatment. 19 cases were complicated with a previous total gastrectomy(gastrectomy group) and 21 cases had no history of surgical operation(non-gastrectomy group). The most common presenting complaint was generalized weakness. The median age at diagnosis was 7(range: 38-79) years in non-gastrectomy group. The mean pos-toperative duration was 7(range: 4-25)years in group of total gastrectomy and mean level of serum vitamin B12 was lower than 100 pg/mL in both group. Peripheral blood revealed thrombocy-topenia, macrocytic anemia and hypersegmented neutrophil in all cases. After treatment of pareliteral vitamin B12, Their clinical symptoms and hematologic findings improved except two patients who had bone marrow with lower cellularity. Cobalamin replacement after total gastrectomy is still missing. Diagnoses are made too late in a population of patients, resulting in irreversible neurological sequale, and we suggest that Pernicious anemia seems not to be very rare in Korea.

VDT작업별 정신사회적 스트레스와 근골격계 장애에 관한 연구

백남종,강종두,주영수,배인근,권호장,박종만,조수헌,김돈규,김재용,최홍렬 大韓産業醫學會 1998 대한직업환경의학회지 Vol.10 No.4

It has been hypothesized that jobs that have both high psychological demands and low decision latitude("job strain") can lead to musculoskeletal disorder. The objective of this study was to test whether job strain was correlated with the presence of work-related musculoskeletal disorder, especially myofascial pain syndrome(MPS). Information on demographic factors, confounders such as household load and taking care of children or not, and scores for decision latitude, job demand, and social support was obtained by self-administered questionnaire, which had been developed in Korean language, by adopting NIOSH instrument and Extended Karasek Model(16 items). All subjects were also examined by rehabilitation medicine specialists for musculoskeletal disorders. Subjects(n=370) could be categorized into 4 groups, these were, housewives(n=89), shipyard CAD workers(n=89), general female workers(n=79; nurses, insurance counselors, public officials, clerks, etc), and telephone directory assistance operators(n=113). Results from univariate analyses indicated that all demographic factors, all confounders, scores for decision latitude and social support were not associated with the risk of musculoskeletal disorder. However, score for job demand was higher in musculoskeletal disorder cases than others. In subgroup analysis, this association was convinced again, in telephone directory assistance operators. Job strain model showed that the group of telephone directory assistance operators was high-stain group, and OR of musculo skeletal disorder was 2.446(95% C. I. : 1.174, 5.096), when comparing this with the low strain group. In conclusion, job strain is a risk factor for work-related musculoskeletal disorder.

골내 고정 장치용 초내식성 오스테나이트 및 듀플렉스 스테인리스강 가공재의 특성

오근택,강국진,박용수,김경남 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.3

Nickel is one of the most common causes of allergic contact dermatitis and hypersensitivity. In case of stainless steel as biomaterials, the higher the corrosion resistance and the lower the nickel content, the better it is or the human body. However, because nickel plays an essential role in the stabilization of the austenitic phase and the corrosion resistance of stainless steel, it is difficult to remove the nickel from the constituents of stainless steels completely. Therefore, the purpose of this study was to investigate corrosion resistance, cytotoxicity, and mechanical property of super stainless steels, which had high corrosion resistance by synergistic effect of Mo(or W) and N, with respect to nickel content and to evaluate their potential for orthodontic applications. Super austenitic stainless steel(SR-50A) had high nickel content of 22% and super duplex stainless steels nickel contents of 6~10%. Super austenitic and duplex stainless steels had nitrogen contents of above 0.2%. Also, these steels had high Mo or W contents which were able to increase the localized corrosion resistance. In terms of hardness, super stainless steels, which had Vickers hardness values of 374~400 Hv in cold-rolled state and 186~285 Hv in annealed state, exhibited higher values than 316L S. S.. Duplex stainless steels exhibited higher mechanical properties than austenitic stainless steels. In terms of corrosion resistance, super stainless steels exhibited lower passive current density(2.3~3.8 ㎂/cm^2) than pure Ti(6.6㎂/cm^2) in the body-simulated solution and similar potentiodynamic polarization behaviors. Pitting corrosion occurred in 316L S. S. but not in the others. Thus these steels were considered to have high corrosion resistance in the human body. In terms of cytotoxicity, SR-5OA and SAF2507 exhibited none cytotoxicity and the others slight. This results indicated that the cytotoxicity of alloys containing nickel had no relation with nickel content because SR-5OA with the highest nickel content exhibited none cytetoxicity In conclusion, it is considered that super stainless steels with high corrosion resistance and good biocompatibility can be used for orthodontic applications because of the enhanced passive film by high addition of Mo, W, N, etc.

한국인 강박장애와 Val-158-Met Catechol-O-Methyltransferase 유전자 다형성 간의 상관성 연구

천근아,김세주,김찬형,구민성,남윤영,박성혁,이홍식 大韓神經精神醫學會 2006 신경정신의학 Vol.45 No.5

목적 COMT(Catechol-O-Methyltransferase) 효소는 도파민성과 노어아드레날린성 체계의 조절에서 매우 중요한 작용을 하며 염색제 22q11에 위치해 있다. 일부의 강박장애 환자들은 도파민 차단제에 좋은 치료 반응을 보이며 이런 현상은 COMT가 강박장애의 병인론에 역할을 하고 있을 가능성을 말해준다. Val-158-Met COMT 유전자의 다형성은 효소의 감소를 유도하는 L(저활성) 대림형질, 활성의 증가를 유발하는 H(고활성) 대립형질로 알려져 있으며 L 대립형질 또는 LL 유전형이 강박장애와 연관이 있다는 보고가 있으나, 아직까지 강박장애와 COMT 다형성 사이의 연관성에 대한 연구결과들은 일관되지 않다. 따라서 본 연구에서는 한국인 강박장애 환자들을 대상으로 Val-158-Met COMT 유전자의 다형성과의 연관성을 알아보고자 하였다. 방법 2002년 3월부터 2004년도 2월까지 약 24개월동안 서울지역 일 대학병원과 경기지역 일 대학병원 강박장애 클리닉을 방문하여 강박장애로 진단받은 124명의 환자들을 연구대상으로 하였고 정상 대조군으로는 나이와 성별을 고려하여 자원자 170명이 선별되어 포함되었다. 강박장애군과 정상 대조군의 혈액으로부터 유전자 추출 후 COMT 유전자 형벌 (genotyping)을 시행하였다. 다형성을 H/H 와 H/L, L/L 유전형으로 나눈 뒤 강박장애와 정상대조군 사이의 유전자 빈도를 카이 검정법으로 비교하여 연관성을 관찰하었다. 또한 강박장애 환자들에게 시행한 YBOCS로부터 측정한 강박장애 심각도 및 Hamilton Depression Raing Scale (HDRS) 총점과 COMT 유전자 다형성 사이의 연관성을 비교하였다. 결과 본 연구 결과 한국인 강박장애와 COMT 다형성 간에는 유의한 상관성이 관찰되지 않았다. YBOCS 심각도와 COMT 유전자형과의 유의한 연관성이 관찰되지 않았다. 그러나, 강박장애 환자군들의 COMT 유전자형 세 군 사이의 우울증상 점수에서는 유의한 차이가 관찰되었다. 결론 한국인에서 강박장애와 COMT 유전자 다형성 사이에는 연관성이 없었다. 그러나, COMT의 H 대립형질과 강박장애 군에서 공존하는 우울증상 척도가 유의한 연관성을 보인 현상은 COMT 유전자의 다형성이 강박장애의 공존 우울증상에 영향을 미칠 수 있는 가능성을 시사한다고 생각된다. Objectives : The definite cause of obsessive-compulsive disorder (OCD) is still unknown. Evidences from familial, twin and segregation studies support the role of a genetic factor. There are also growing evidence indicating that OCD has specific neurochemical and neuroanatomical basis. Derived from the effectiveness of treatment with dopamine receptor blocker in certain part of OCD patients (eg. SSRI treatment-resistant OCD), several candidate genes related to dopamine dysregulation have been hypothesized to play an important role in the development of OCD. One of them is the Catechol-O-Methyltransferase (COMT) gene. The aim of this study was to investigate the association between COMT and OCD in Korean population. Methods : 124 OCD patients and 170 normal controls participated in this study. Genomic DNA was extracted from their blood. The genotypes and allele frequencies of the COMT polymorphism between OCD group and control group were compared. We investigated the association between severity of OCD assessed by Yale-Brown obsessive compulsive symptom scale (YBOCS) and Hamilton depression rating scale (HDRS) scores and COMT polymorphism. Results : In this case-control study, we could not find any association between COMT gene polymorphism and development of OCD. In OCD group, patients with H/H genotype had significantly higher scores for the HDRS than those with H/L or L/L genotype. Conclusion : In this study, there was no difference in genotype distributions of COMT between OCD and control groups. However, H/H genotype of COMT gene polymorphism might be related to depressive symptoms in OCD patients.

인슐린 비의존성 당뇨병에 동반된 심상성 천포창 1 례

이상준,박진용,임태형,윤영호,권순대,남창욱,허규찬,박근용,구본식,김상표,장종억 啓明大學校 醫科大學 1997 계명의대학술지 Vol.16 No.3

저자들은 인슐린 비의존형 당뇨병 환자에서 통증성 구강내 미란 및 전신성 수포성 미란을 동반한 심상성 천포창 1예를 경험하였기에 문헌고찰과 함께 보고하는 바이다. Various skin conditions such as diabetic dermopathy, necrobiosis lipoidica diabeticorum, bullosis diabeticorum, granuloma annulare occur frequently in diabetes, although common lesions may be associated by chance. Pemphigus vulgaris(PV) is a blistering skin disease seen predominantly in elderly patients. This disorder is characterized by the loss of cohesion between epidermal cells with the resultant formation of intraepidermal blisters. These blisters rupture easily, leaving denuded areases that may crust and enlarge peripherally. In half or more of patients, lesions begin in the mouth: approximately 90% of patients have oromucosal involvement at some time during the course of their disease. But the relationship of this disorder with diabetes is not clear. We experienced a case of pemphigus vulgaris associated with NIDDM in 67 years old woman who was admitted due to painful oral ulcer and control of blood glucose, so we present this case with a review of literatures.