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윤대현,이영준,김옥화 인제대학교 2003 仁濟醫學 Vol.24 No.1
Objectives : The purpose of this study was to evaluate the findings of quantitative MR imaging and Gd(DTPA)^(2-) -enhanced MR imaging of articular cartilage degraded by collagenase type Ⅶ and chondroitinase ABC. Methods and Materials : Twenty-one cartilage-bone blocks obtained from 10 pig patellae were cultured with collagenase and chondroitinase. The enzymatic degradation was conducted with different concentrations and with differents durations of culture, 0. 20, 40. 80 hours respectively. The change of signal intensity and relaxation times of the articular cartilage, which was caused by the depletion of the collagen and proteoglycan, was studied with an MRI using the two different techniques mentioned above. This data was also compared with that acquired from the normal cartilage. Four different histologic stains were performed to identify a loss of collagen and proteoglycan in cartilage. Results : The depletion of the collagen and proteoglycan induced by enzymes was identified in histologic studies. Both the signal and contrast to noise ratio decreased in the groups of 40 and 80 hours enzymatic culture, as compared with the groups of 0 and 20 hours culture. A statistically significant Gd(DTPA)^(2-) -enhancement was noted in the cartilage treated with chondroitinase, resulting from depletion of the proteoglycan, but the degree of enhancement did not correlate to the duration of the culture. There was no correlation between the concentration of the enzymes or duration of culture and T1, rho, and T2 relaxation times of the cartilage. The T1 relaxation time of the cartilage after Gd(DTPA) ^(2-) -enhancement decreased in the following order : group B, group C, group A, and group D. Conclusion : The results indicate that Gd(DTPA) ^(2-) -enhancement rather than signal change or T1, rho,T2 relaxation parameters are sensitive to depict the proteoglycan depletion. Gd(DTPA) ^(2-) -enhanced MR imaging have the potential as a mean of imaging modality for early detection of biochemical degradation of the articular cartilage at 1.5 T MRI.
The Relationship between Type D Personality and Suicidality in Low-Income, Middle-Aged Adults
윤대현,김석주,이종하,김표민,박두흠,류승호,유재학,하지현 대한신경정신의학회 2015 PSYCHIATRY INVESTIGATION Vol.12 No.1
ObjectiveaaLow-income adults are considered to be a group at high risk for suicide. We sought to examine the effect of type D personality and other socio-demographic factors on suicidality in low-income, middle-aged Koreans. MethodsaaIn total, 306 low-income, middle-aged Koreans [age: 49.16±5.24 (40–59) years, 156 males, 150 females] were enrolled from the Korean National Basic Livelihood Security System. Socio-demographic data, including employment status, income, health, marital status, and educational attainment, were gathered. Beck’s 19-item Scale for Suicidal Ideation (SSI) was applied to evaluate suicidality, and the DS14 was used to assess type D personality. ResultsaaUnemployment (p<0.01) and absence of spouse (p=0.03) predicted higher SSI scores independent of other socioeconomic factors. All type D personality scores [i.e., negative affectivity (NA), social inhibition (SI), and total score] predicted higher SSI scores independent of all socioeconomic factors (all, p<0.001). Subjects with type D personality had higher SSI scores (p<0.001), and the association between suicidality and socio-demographic factors (employment or physical health) could be found only in subjects without type D personality. ConclusionaaType D personality was a risk factor for suicide in low-income Koreans, independently from socio-economic factors. In addition, the socio-demographic factors were less prominently associated with suicidality in those with type D personality.
X-선 회절을 이용한 비정질 SiO$_2$ Gel 의 구조 해석에 관한 연구
윤대현,김기선,정현채,Yoon dai Hyun,Kim Ki Sun,Jung Hyun Chai 대한화학회 1990 대한화학회지 Vol.34 No.5
Sol-gel법을 통하여 만들어진 비정질 SiO$_2$ gel들의 구조가 열처리 온도, 80$^{\circ}C$, 250$^{\circ}C$, 450$^{\circ}C$ 그리고 1000$^{\circ}C$에 따라 변화하는 과정을 X-선 회절 강도 측정으로부터 구한 동경분포곡선을 이용하여 알아보았다. 그리고 이를 6개의 결정들과 비교하여 예상되는 구조를 밝혔다. 각 시편들은 용융법으로 구한 SiO$_2$의 구조와 O-O결합쌍을 제외하고는 가장 유사한 구조를 가지며 cubic형으로 나타났다. The structural variation process of amorphous SiO$_2$ gel upon heat-treatment conditions of 80, 250, 450 and 1000$^{\circ}C$ has been studied by using the radial distribution functions (RDF$_{obs}$) estimated from the X-ray diffraction intensities. The expected gel structure was determined by comparing the RDF$_{obs}$ with those for the other six standard samples selected appropriately. The structure of specimens prepared by sol-gel method is well consistent with that of fused SiO$_2$ (${\beta}$-cristobalite with cubic symmetry) except a slight difference in O-O band distance.