Ti-6Al-4V 합금의 표면개질에 의한 calcium phosphate의 형성

박은진,김도균,김교한,고 융부,김형일,정용수 대한치과기재학회 2000 대한치과재료학회지 Vol.27 No.1

The purpose of this study os to investigate the formation of calcium phosphate on Ti-6Al-4V surface on aqueous solutions containing phosphate and calcium ions. The surface of Ti-6Al-4V specimens were treated in phosphate buffered solutions for 3 days followed by immersion in calcium phosphate buffered solutions for 10 days. These solutions have different concentration and pH(pH 5.8, 7.0, 8.0) one another. Then, the specimens treated with P and Ca ions and control group without surface treatment were immersed in Hanks' balanced solution for 30 days to make sure the effectiveness of this surface treatment. All specimens were characterized using scanning electron microscopy(SEM), X-ray diffractometry(XRD) and Fourier transform infrared spectrophotometry(FT-IR). The amount of crystallized particles formed on the specimens by surface treatment was significantly increased in all experimental conditions as compared with that immersed only in Hanks' solution. Dense granular shaped precipitates were observed on the surface and these particles were recognized as calcium phosphate similar to HA(hydroxyapatite) or TCP(tri-calcium phosphate).

Effect of TaC-Coated Crucible on SiC Single Crystal Growth

Lee, Doe Hyung,Lee, Hee Tae,Bae, Byung Joong,Lee, Hee Jun,Lee, Sang II,Park, Mi Seon,Lee, Won Jae,Yeo, Im Gyu,Eun, Tai Hee,Chun, Myong Chuel Trans Tech Publications, Ltd. 2014 Materials science forum Vol.778 No.-

<P>The present research was focused to extensively investigate the effect of TaC-coated crucible on the SiC crystal growth and then compare the difference of various properties between SiC crystals grown in conventional graphite crucible and TaC-coated crucible. The bulk growth was conducted around 2200°C of the growth temperature and 40 mbar of an argon atmosphere for the growth pressure. The better crystalline quality was obtained from the crystal grown in TaC-coated crucible. The SiC crystal grown in the TaC-coated crucible exhibited superior characteristics than SiC crystal grown in the conventional crucible in terms of the crystal quality and defect density. Furthermore, nitrogen incorporation in SiC crystal grown in the TaC-coated crucible was definitely decreased.</P>

만연한 와스타와 무너진 일반화된 신뢰 -레바논과 이집트를 중심으로-

김도형 ( Kim Doe-hyung ) 부산외국어대학교 지중해지역원 2024 지중해지역연구 Vol.26 No.1

Trust serves as a crucial factor in cultivating societal cohesion, with generalized trust representing a fundamental aspect of trust in most people. The Arab world has consistently exhibited distrust in institutions, yet issues related to generalized trust have not surfaced overtly surfaced. However, various surveys such as World Values Survey have highlighted concerns regarding generalized trust in the Arab world. Particularly, Lebanon and Egypt manifest collapsed generalized trust, with a majority of respondents indicating distrust in most people, surpassing 90%. This study focuses on the phenomenon of collapsed generalized trust in Lebanon and Egypt, specifically examining it as corruption with a focus on Wasta. Wasta is known for its dual nature, encompassing both social capital and corruption. However, the evolution of Wasta’s role in the formation of modern states in Lebanon and Egypt has consistently presented its corrupt aspects. This study, seeking to understand the impact of Wasta on the collapsed generalized trust in Lebanon and Egypt, conducted binary logistic regression analysis based on recoded items including “Most people can be trusted.” as the proxy of generalized trust and “It is impossible to get a job without wasta vs. that posts are attributed according to qualifications.” as representing Wasta provided by World Values Survey. The findings of this study indicate that Wasta is related to collapsed generalized trust in both countries. Specifically, odds ratios in empirical results have shown increased distrust in most people when the perceived level of Wasta is increased. Hence, the hypothesis that pervasive Wasta generates the collapsed generalized trust in recent Lebanon and Egypt can be supported. This suggests a recommendation for policymakers in Lebanon and Egypt to exert control over Wasta as a means to enhance generalized trust to increase social efficiency. Furthermore, this study underscores the need to break the vicious cycle of corruption, declining generalized trust, and the reproduction of corrupt behaviors. It urges policymakers to address these issues to foster societal improvement.

Thermally Switchable One- and Two-Dimensional Arrays of Single-Walled Carbon Nanotubes in a Polymeric System

Doe, Changwoo,Jang, Hyung-Sik,Kim, Tae-Hwan,Kline, Steven R.,Choi, Sung-Min American Chemical Society 2009 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.131 No.45

<P>Fabrication of highly ordered arrays of single-walled carbon nanotubes (SWNTs) has been of great interest for a wide range of potential applications. Here, we report thermally switchable one- and two-dimensional arrays of individually isolated SWNTs formed by cooperative self-assembly of functionalized SWNTs and a block copolymer/water system. Small-angle X-ray scattering measurements reveal that when the block copolymer/water system is in an isotropic phase, two-dimensional hexagonal arrays of SWNTs are formed by depletion attraction, and when the block copolymer/water system is in a lamellar phase, one-dimensional lattices of SWNTs intercalated in the polar regions of the polymeric lamellar structure are formed by entropically driven segregation and two-dimensional depletion attraction. These two SWNT arrays are thermally interchangeable, following the temperature-dependent phase behavior of the block copolymer/water system.</P>

급성 및 보상기의 전정 신경염에서 전정 기능 검사

이형,이승환,임정근,이상도,박영춘,오희종 대한신경과학회 2000 대한신경과학회지 Vol.18 No.1

파킨슨병에서의 전정기능 이상

이형,김태완,김지언,이성룡,오희종,임정근,이상도,박영춘 대한신경과학회 1998 대한신경과학회지 Vol.16 No.2

Immunohistochemical Analysis of White Hair in Alopecia Areata

Roh, Doe Kywn,Choi, Sung Woo,Yi, Jong Yuk,Kim, Hyung Ok,Kim, Chung Won 가톨릭대학교 2000 Bulletin of The Catholic Research Institutes of Me Vol.28 No.-

There had been some reports of resistant white hair remaining in the alopecic patch area or regenerating white hair prior to emergence of black hair on the patients with alopecia areata. But relatively few studies pointed out this subject yet. The purpose of this study was to evaluate the histopathologic property of white and marginal hair follicles in alopecia areata patients using immunohistochemical markers. Eight patients with alopecia areata who had white hair on his scalp were selected, then obtained biopsy samples from white hair follicles, and marginal black hair follicles respectively. Immunohistochemical staining had been done with CD4, CD8, Mel-5, c-kit antibodies on both groups. Then, two different observers counted perifollicular infiltrated cells and the data scored with SAS program for statistical analysis. 1. Decreased ratio of CD4 lymphocyte to CD8 lymphocytes were observed on the white hair area(CD4:CD8=1.85:1, 53.85%) (CD4:CD8=1.16:1, 85.71%) but statistically not significant differences were seen and the ratio between them proved to be in the regeneration stage alopecia areata. 2. Significantly lower levels(p<0.05) of Mel-5/c-kit positive ratio of melanocyte observed on white hair area(c-kit:Mel-5 = 3.84:1, 26.01%) compared with marginal hair area(c-kit:Mel-5=1.74:1, 57.33%), furthermore decreased ratio of Mel-5(+) cells(black:white=2.17:1, 46.14%), but increased ratio of c-kit(+) cells(black:white=1:1, 99.16%) were observed on the white hair area : more Mel-5(-), c-kit(+) cells(precursor melanocyte) were observed on the outer root sheath of white hair area Consequently, we propose that the regenerating white hair area contained much more precursor type melanocytes and it is related to the whitish nature of regenerating hair. (Korean Journal of Dermatology 37(7):854-860, 1999)

만성 폐쇄우각 녹내장으로 진단된 만성 두통

이상도,이동국,임정근,김광수,이형,박영춘 啓明大學校 醫科大學 1992 계명의대학술지 Vol.11 No.4

A sudden increased of the intraocular pressure in angle-closure glaucoma can cause severe pain and sudden visual loss. We experienced a case of chronic angle-closure glaucoma, who complained of intermittent unilateral pulsating headache without increasing intraocular pressure simulating migraine or other wype of headache.

중추신경계질환에서 병소부위에 다른 요류역학적 관찰

이동국,이상도,유영수,박영춘,임정근,이 형 啓明大學校 醫科大學 1993 계명의대학술지 Vol.12 No.2

This study was undertaken to evaluate the correlation between urodynamic findings and localization of CNS lesions in patient with voiding disturbance. The patient group consisted of 48 patients (35 male and 13 female) with various localization of CNS lesions confirmed by CT or MRI among which were 9 cerebral cortex, 8 putamen and internal capsule, 6 thalamus and internal capsule, 7 brain stem and 18 spinal core. m and 18 spinal core. Nineteen of the 42 patients with various CNS lesions above sacral crod showed detrusor hyperreflexia. Six of the 7 patients who had suprasacral cord lesion and detrusor hyperreflexia showed detrusor sphincter dyssynergia. In 6 patients with sacral cord lesions, 5 patients showed detrusor areflexa. In summary, detrusor sphincter dyssynergia with detrusor hyperreflexia and detrusor areflexia seemed to be specific urodynamcic pattern of suprasacral spinal cord and sacral cord lesion, respectively. But other CNS lesion showed no consistent specific urodynamic pattern.

급성 뇌교 경색의 임상 연구

장상섭,이형,김지언,이상도,임정근,김근호,박영춘,김태완,김진석 啓明大學校 醫科大學 1999 계명의대학술지 Vol.18 No.1

내인성 뇌교 혈관의 공급 영역에 따라 단독 뇌교 경색은 전측(내측과 외측), 피개, 외측 뇌교경색의 세가지 유형으로 분류할 수 있고 이들의 임상 양상과 국소 해부학적 상관 관계는 일치하였다. 전측 뇌교경색은 주로 피질 척수로를 손상시켜 상하지의 부전 편마비를 일으키며 반수 이상의 환자(59%)에서 피개 징후와 증상을 동반하였다. 피개경색은 현훈, 의식변화, 안 운동장애, 감각장애 및 뇌신경마비같은 피개 증상과 징후가 나타나며 일부(30%)에서 경미한 운동장애가 동반되었다. 단독뇌교 경색은 주로 기저 동맥의 관통 동맥 폐색에 의해 발생하곡 대혈관 질환이나 심 색전증 또한 단독 뇌교 경색의 원인이 되었다. Background : In a pontine infarction, variable neurologic deficits present because the pons is very complicated organ including cranial nerve nuclei and several fiber tracts. It's the aim of this study to clarify the clinicotopographical correlation of isolated acute pontine infarcts. Methods : We studied 33 patients with acute pontine infarct and classified them into three subtypes on the basis of lesion location on MRI. Clinical features, angiographic findings and risk factors were compared. Results : Twelve patients had a ventromedial pontine infarcts, in which clinical findings included dysarthria (N=12), hemiparesis (N=12) and tegmental signs (N=6). Five patients had a ventrolateral pontine infarcts, in which clinical findings included vertigo (N=3), hemiparesis (N=3) and sensory disturbances (N=2). Fifteen patients had a tegmental infarcts, in which clinical findings were vertigo (N=13), eye movement disorders (N=10) such as abducence palsy; inter-nuclear opthalmoplegia, ocular bobbing, and sensory disturbance (N=4). Emboligenic heart disease (N=3/33 9.1%) and sign-ificant stenosis of vertebro-basilar artery (3/16 18.7%) were observed. Summary: Corresponding to territories of intrinsic pontine vessels, isolated pontine infarcts could be classified into three main syndromes. Isolated pontine infarcts were usually due to thrombosis of per-forating arteries, but large artery stenosis and cardioembolism also could be causes of isolated pontirie infarcts.