수용액에서 〔Co(en)_3〕Cl_3 및 〔Co(NH_3)_6〕Cl_3 착물의 이온 해리에 미치는 압력의 영향

鄭倧在,盧炳吉 慶北大學校 物理化學硏究所 1986 硏究論文集 Vol.7 No.-

25℃에서 〔Co(en)_3〕Cl_3, 〔Co(NH_3)_6〕Cl_3 수용액의 열역학적 해리상수를 1∼2000bar의 압력범위에서 전도도법으로 측정하였다. 착물이 해리할 때 하전을 띤 이온이 생성하여 부피가 감소하므로 압력이 증가함에 따라 해리상수(K^T)는 커졌다. 즉 〔Co(en)_3〕Cl_3에 대한 _pK^T값은 1bar에서 2.16, 500bar에서 2.08, 1000bar에서 2.08, 1500bar에서 2.05, 2000bar에서는 2.03이었고, Co(NH_3)_6〕Cl_3의 _pK^T는 1bar에서 2.02, 500bar에서 1.96, 1000bar에서 1.90, 1500bar에서 1.88, 2000bar에서는 1.87이었다. 각 압력에서 Stokes반경과 해리상수(K_T)값을 비교 분석하여 착물의 이온쌍 형성에는 정전기적 인력 이외에 Internal Conjugate Base(ICB) 효과도 영향을 미쳤으며 이 효과는 압력이 증가할 수록 커졌다. The thermodynamic dissociation constants of 〔Co(en)_3〕Cl_3 and 〔Co(NH_3)_6〕Cl_3 in aqueous solutions at 25℃ and at the pressure from 1 bar to 2000 bars were measured by conductometric method. The dissociation constants were increased with pressure elevation because of volume decreasing by the formation of charged ions during dissociation reaction. That is, the _pK^T values of 〔Co(en)_3〕Cl_3 were 2.16 for 1 bar, 2.08 for 500 bars, 2,08 for 1000 bars, 2.05 for 1500 bars and 2.03 for 2000 bars, respectively and those of 〔Co(NH_3)_6〕Cl_3 were 2.02 for 1 bar, 1.96 for 500 bars, 1.90 for 1000 bars, 1.88 for 1500 bars and 1.87 for 2000 bars, respectively. Comparing and analyzing the values of Stokes' radii and K^T, the formation of ion pair compound was affected by not only the electrostatic interaction, but also the Internal Conjugate Base(ICB), which was incresed by the elevation of the pressure.

유치열과 혼합치열기 어린이의 상악 절치부 외상

정주현,이제호,김성오,최병재 大韓小兒齒科學會 2004 大韓小兒齒科學會誌 Vol.31 No.2

현대인의 생활양식과 환경이 도시화 및 인공화되고 취미활동이 다양화됨에 따라 외상을 받을 수 있는 요인들을 증가하고, 특히 어린이 활동량이 많아져 외상의 기회가 잦아지고 있다. 어린이에서 외상이 발생하는 경우, 어린이의 일상적인 활동 뿐 아니라, 사회성 및 정서 발달에도 영향을 미칠 수 있으며, 그 보호자에게도 부정적인 영향을 미칠 수 있기에 외상의 발생 빈도를 줄이고 예방하는 것이 중요하다. 본 연구는 유지열과 혼합치열기에 발생하는 치아 외상을 예방하기 위한 기초 자료를 얻기 위하여, 특히 구강악안면부의 외상시 치아 외상을 가장 많이 받는 상악 유절치와 영구절치를 연구하기 위하여, 2002년 6월부터 2003년 5월까지 연세대학교 치과대학병원 소아치과에 내원한 유치열과 혼합치열기의 신환 8.799명중 상악 절치부 외상을 주소로 내원한 어린이 487명(남자 316명, 여자 171명)의 상악 절치 955개(유절치543개, 영구절치 412개)를 조사하여 다음과 같은 결과를 얻었다. 1. 상악 절치부 외상이 호발하는 나이는 유절치에서 1~3세, 영구절치에서 7세였으며 남자대 여자의 비율은 1.85:1이었다. 2. 상악 절치부 외상은 유절치와 영구절치 모두 오후 시간에 많이 발생하였으며, 유절치는 외상 장소로 집이 가장 많았고 (44.1%), 영구절치는 길에서 다치는 경우가 가장 많았다(17.5%). 3. 외상의 원인으로 유절치와 영구절치 모두 넘어져 다치는 경우가 가장 많았으며(39.8%, 12.9%), 다음으로 부딪히는 경우가 많았다(22.2%, 6.0%). 유절치에서는 다음으로 떨어져 다치는 경우, 교통사고, 폭력과 운동에 의한 외상 순이었으며, 영구절치에서는 폭력, 운동, 교통사고, 떨어져 다치는 순이었다. 4. 조사대상 어린이 1명당 유절치는 1.6개, 영구절치는 2.8개에 외상을 입었다. 5. 유절치와 영구절치 모두에서, 치관 파절 양상은 치수미노출 치관 파절이 많았고, 치주조직 외상 양상은 아탈구가 가장 많았다. 최근 어린이의 단체 생활이나 운동과 취미 활동에 참여하는 나이가 예전에 비하여 점차 낮아지고 있어, 이번 연구 결과와 같이, 외상이 발생하는 나이 역시 지속적으로 낮아질 수 있다. 나이에 따른 어린이의 외상을 받는 장소는 특별한 곳이 아닌, 집이나 학교와 같은 일상의 생활공간이기 때문에 단순한 주의만으로도 외상의 발생을 예방할 수 있을 것으로 사료된다. In children, change in lifestyles such as an increase in participation of physical activities has increased the chance of receiving an injury, harming the child and their parents. This study was carried out to give basic information of traumatic injuries to the upper anterior teeth which can be used in prevention of future complications that may arise. From June, 2002 to May, 2003, of the 8,799 children in their primary and mixed dentition visiting Department of Pediatric Dentistry, College of Dentistry, Yonsei University. 955 upper anterior teeth(primary 543, permanent 412) of 487 children(ma1e 316, female 171) with traumatic injures to the upper incisors were studied. The results were as follows: 1. Trauma to the primary teeth prevailed at the age of 1-3 and to the permanent teeth at the age of 7. The male to female ratio was 1.851. 2. Trauma to the upper incisors for both the primary and permanent teeth occurred in the afternoon. Primary teeth were injured most frequently in the home(44.1%) and the permanent teeth outdoors, in the street(l7.5%). 3. Both the primary and permanent teeth were most injured by fall-down injuries(39.8%, 12.9%), and next were collisions(22.2%, 6.0%) :For the primary teeth, high fall, traffic accident, violence and sports are next in order, and for the permanent teeth, violence, sorts, traffic accidents were next. 4. Average number of 1.6 primary teeth and 2.8 permanent teeth were injured with the right central incisor most prevailing. 5. Crown fracture without pulpal exposure and subluxation injures were highest in frequency in both the primary and permanent teeth.

급성하벽심근경색에서 전흉부유도 ST절 하강의 의의

정병천,배호상,곽동훈,김영태,배용학,황종현,임현주,류재근,조용근,채성철,전재은,박의현 慶北大學校 醫科大學 1997 慶北醫大誌 Vol.38 No.2

목적 : 급성하벽심근경색증 환자에서 심전도상 흔히 동반되는 전흉부유도 ST절 하강의 의의를 알아보았다. 방법 : 심근경색후 24시간에서 48시간에 얻은 심전도를 기준으로 52명의 급성하벽심근경색증 환자를 전흉부유도에서 ST절의 하강이 있는 군과 없는 군으로 나누었으며 심도자, 관상동맥조영술, 심초음파도 및 방사성 핵종을 이용한 좌심구혈율 측정 등을 시행하였다. 결과 : 1) 좌심실확장기말압은 전흉부유도에서 ST절의 하강이 있는 경우에서 16.9±5.33mmHg로 없는 경우의 11.0±4.02mmHg보다 유의하게 높았다(p<0.05). 그러나 운동량 및 좌심구혈을은 흥부 유도상 ST절의 하강이 있는 경우 7.6±3.0 METs 및 53.9±9.1%로 없는 경우의 9.1±2.7 METs 및 54.6±9.5%보다 낮았으나 통계적 유의성은 없었다(p=0.180, p=0.823). 2) 관상동맥조영술상 전흉부 ST절의 하강이 동반된 군에서는 유의한 좌전하행지나 좌회선지의 협착이 있는 경우가 60.9% 및 57.9%로 ST절의 하강이 없는 군에서의 34.5% 및 7.7%와 비교해 좌관상동맥에 협착이 동반된 경우가 많았다(p=0.050, p=0.001). 3) 관상동맥조영술상 세 혈관질환의 빈도는 흉부유도상 ST절의 하강을 보인 23예에서 10예로 ST절 하강이 없었던 29예중 2예에 비하여 유의하게 많았고(P=0.007), 단 혈관질환의 빈도는 ST절의 하강을 보인 군에서 23예중 5예로 ST절 하강이 없었던 29예중 17예에 비하여 유의하게 적었다(P=0.002). 두 혈관질환의 경우에는 각각 8예와 10예로 양군간에 유의한 차이가 없었다. 4) 흉부유도상 ST절 하강의 빈도는 단 혈관질환 22예 중 5예에서, 두 혈관질환 18예중 8예, 세 혈관질환 12예 중 10예에서 관찰되어 협착이 있는 관상동맥의 수가 많을수록 ST절의 하강이 나타나는 빈도가 많음을 보였다(p=0.00308). 그러나 흉부유도상 나타난 ST절의 하강을 모두 합하여 구한 ST절 하강의 합은 협착이 있는 관상동맥의 수와 통계적인 유의성이 없었다. 5) 심초음파도상 좌심실 하벽의 벽운동은 ST절 하강을 보인 군에서는 akinesia가 83.3%, hypokinesia가 11.1%, 정상 벽운동이 5.6%로, ST절 하강이 없었던 군에서의 dyskinesia가 3.6%, akinesia가 39.3%, hypokinesia가 25.0%, 정상 벽운동이 32.1%와 비교하여 ST절의 하강이 있는 군에서 유의하게 벽운동의 장애가 빈번함을 보였다(p=0.03891). 그러나 좌심실전벽, 측벽 및 중격부위에서는 유의한 벽운동의 차이가 없었다. 결론 : 급성하벽심근경색증 환자의 전흉부유도에서 ST절의 하강이 동반되는 경우 다혈관 질환의 가능성이 높으며 좌심실확장기말압이 상승되었고 운동능력은 감소되어 있었다. 또한 심초음파도상 좌심실하벽의 벽운동장애도 심하였다. 따라서 전흉부 ST절의 하강을 동반한 급성하벽심근경색증 환자는 전흉부유도에 ST절 하강이 없는 경우보다 예후가 불량할 것으로 생각되며, 보다 적극적인 치료가 필요할 것으로 생각된다. The purpose of this study was to determine the significance of precordial ST segment depression appearing during acute inferior myocardial infarction and to assess the correlation of that with angiographic finding. 52 patients were allocated into two groups based on the existence of precordial ST segment depression : 23 patients with ST segment depression and 29 patients without ST segment depression. The extent of coronary artery disease as well as the prevalence of significant stenosis (≥70%) in left anterior descending artery were more frequent in patients showing precordial ST segment depression than in patients not showing them (p=0.050) and the result were similar in cases of left circumplex artery (p=0.001). On echocrdiographic examination of left ventricular (LV) wall motion, it showed more severely decreased inferior LV wall motion in patients showing precordial ST segment depression than in patients not showing them (p=0.03891) even though the other segment of LV wall motion didn't show the statistical difference between both groups. The other cardiac parameters such as LVEDP, exercise amount (METs) and ejection fraction were tend to showing bad profile in patients with precordial ST segment depression. From the above results, we could deduce that patients with precordial ST segment depression have relatively large infarction or concomitant left coronary artery disease, so they need more caution and intensive theraphy.

아세톤-물 혼합용매에서 cis-[Co(en)(NH_3)_2Cl_2]Cl의 수화반응에 미치는 압력의 영향

鄭倧在,李炳煥 慶北大學校 物理化學硏究所 1985 硏究論文集 Vol.6 No.-

전도도법을 이용하여 cis-〔Co(en)(NH_3)_2Cl_2〕^+ 착이온의 아세톤-물 혼합용매에서 온도, 압력 및 용매의 조성변화에 따른 속도상수를 구하였다. 속도상수의 변화로 부터 열역학적 파라미터들을 구하여 이 반응의 메카니즘을 규명하고, 용매의 조성변화에 따른 반응속도상수의 변화를 조사하여 메카니즘을 재확인 하였다. 수화반응의 일차반응 속도상수는 1기압 25℃의 순수물 용매에서는 3.47×10 exp (-4)/sec이고 압력이 증가할수록 감소하였으며 온도가 10℃ 증가함에 따라 약 3배정도 증가하였다. 한편 아세톤의 함량이 증가할수록 반응속도 상수는 감소하였다. 이 반응의 활성화 부피는 2.82∼8.2㎤/mole이며 활성화압축률과 활성화엔트로피는 작은 값들을 나타내므로 이 반응의 메카니즘은 전이상태에서 리간드인 Cl^-이온이 중심금속에서 떨어지는 것이 H_2O가 결합하는 것보다 우세한 I_d 메카니즘일 것으로 추정하였다. 또한 Grunwald-Winstein 식에서 구한 m값이 0.25정도로써 이미 I_d 메카니즘으로 알려진 다른 코발트 착물의 값들과 잘 일치하고 있다. 자유에너지순환도를 이용한 메카니즘의 재확인으로 이 반응착물의 수화는 I_d 메카니즘으로 진행된다는 것을 확인하였다. The rates for the aquation of cis-〔Co(en)(NH_3)_2Cl_2〕Cl in acetone-water mixtures have been measured at various pressures and temperatures by the electric conductivity method. The rate constant measured at 25℃ in pure water solvent is 3.47×10 exp (-4)/sec. Rate constants are increased with increasing temperature, and decreased with increasing pressure and mole fraction of acetone. Activation volumes and other activation parameters are calculated from these rate constants. The activation volumes are all positive and lie in the limited range +2.82∼+8.2㎤/mole. The rate constants in aqueous acetone solution are analyzed with the solvent compositions. Plots of log k_obs vs. Grunwald-Winstein Y values show that log k_obs varies linearly and the gradients are about 0.25. The applications of a free energy cycle relating the process initial state→transition state in water to that in acetone-water mixture show that the changes in solvation of the transition state have a dominant effect on the rate. From these results the aquation of this complex would be discussed in terms of dissociative mechanism (I_d).

Protein Methylase Ⅱ에 依한 Carboxylmethylation이 胎盤組織 Na^+, K^+―ATPase 活性에 미치는 影響

鄭顯,林圭,黃炳斗,李載欣 충남대학교 의과대학 지역사회의학연구소 1987 충남의대잡지 Vol.14 No.2

Partial purified human placental Na+, K+-ATPase and plasma membrane proteins were enzymically carboxylmethylated by human placental protein methylase II, and changes in their Na^+, K^+-ATPase acivities were studied. 1.. The rates of enzymatic carboxylmethylation by protein methylase II of the placental Na^+, K^+-ATPase fraction, which had been purified 19-fold, and of the plasma membrane proteins were 0.71 and 0.50 pmoles/mg protein/minute, respectively, when measured by the incorporation of ^3H-methyl group from S-adenosylmethionine into the proteins. 2. The enzymatic carboxylmethylation was found to be a function of the concentration of S-adenosylmethionine as well as of the substrates and incubation time. 3. More than 60% of the carboxylmethylated Na^+, K^+-ATPase fraction and plasma membranes were demethylated during 30 minutes incubation at pH 7.4, with the demethylation half time of 15 and 8 minutes, respectively. 4. The placental Na^+, K^+-ATPase fraction and plasma membrane proteins were found to be better substrates for protein methylase II than histone IIA. 5. Polyacrylamide gel electrophoresis of the carboxylmethylated plasma membrane proteins and Na^+, K^+-ATPase fraction showed multiple carboxylmethylated subfractions: in the plasma membrane, subfractions of molecular weight 95000, 43,000, 26,000 and less than 20,000, among which molecular weight 26,000 fraction was most strongly carboxylmethylated, and in the Na^+, K^+-ATPase fraction, subfractions of molecular weight 50,000, 40,000, 26,000, and less than 20,000 were carboxylmethylated. 6. Na^+, K^+-ATPase activities of the plasma membrane and the Na^+, K^+-ATPase fraction were increased by 36% and 9% when carboxylmethylated, and decreased by 25% and 21% after cAMP-dependent phosphorylation, respectively. These results suggest that protein merhylase II may have some indirect role in the regulation of Na+, K+-ATPase activity.

조기 후두암의 Docetaxel-Cisplatin 유도 화학요법에 대한 임상연구

정주섭,권보란,최영진,왕수건,이병주,조군제 부산대학교 병원 암연구소 2009 부산대병원학술지 Vol.- No.25

과학수업모형의 비교 분석 및 내용과 활동 유형에 따른 적정 과학수업모형의 고안

정완호,권재술,최병순,정진우,김효남,허명 한국교원대학교 과학교육연구소 1996 청람과학교육연구논총 Vol.6 No.1

The purpose of this study is to develop appropriate science teaching models which can be applied effectively to relevant situations. Five science teaching models; cognitive conflict teaching model, generative teaching model, learning cycle teaching model, hypothesis verification teaching model and discovery teaching model, were identified from the existing models. The teaching models were modified and in primary and secondary students using a nonequivalent pretest-posttest control group design. Major findings of this study were as follows: 1. For teaching science concepts, three teaching models were found more effective; cognitive conflict teaching model, generative teaching model and discovery teaching model. 2. For teaching inquiry skills, two teaching models were found more effective; learning cycle teaching model and hypothesis verification teaching model. 3. For teaching scientific attitudes, two teaching models were found more effective; learning cycle teaching model and discovery teaching model. Each teaching model requires specific learning environment. It is strongly suggested that teachers should select a suitable teaching model carefully after evaluating the learning environment including teacher and student variables, learning objectives and curricular materials.

토끼의 만성 뇌혈관연축 모델에서 혈관확장제에 의한 비가역적 혈관수축의 발현시기와 혈관벽의 전자현미경소견상 이상소견이 발현되는 시기와의 시간관계

정천기,조병규,김하영,지제근,김종재,한대희 대한신경외과학회 1995 Journal of Korean neurosurgical society Vol.24 No.11

One of the characteristics of the cerebral vasospasm is its irreversibility with the vasodilators.Under the hypothesis that the irreversibility with vasodilators might be caused by the structural change in the arterial wall, authors examined the chronological relationships between the irreversibility and the electron microscopic findings of the arterial wall in the rabbit chronic vasospasm model. The development of the vasospasm and the irreversibility of the vasospasm with the intra-arterial papaverine were defined angiographically. After the second angiography done in one to 30 days after subarachnoid hemorrhage(SAH), eighteen rabbits were sacrificed, and the basilar artery was examined with electron microscope. Arterial narrowing was the severest one day after SAH(54.1% of the pre-SAH diameter), and was maintained up to 30 days afer SAH. The irreversibility of the arterial constriction with the papaverine developed 5 days after SAH, which had a tendency to recover 6 to 9 days after SAH. However the irreversibility was noted again 16 days after SAH. Electron microscopy revealed the endothelial wrinkling, disorganization of muscle fiber, myonecrosis, thickening of smooth muscle fibers, and increase of connective tissue in the tunica media. These structural changes were severest one day after SAH, and gradually diminished up to 30 days after SAH. These data show that there are no chronological relationships between the irreversibility and the structural change per se. However the fact that the irreversibility developed during the reparative phase of the arterial wall injury by SAH suggests that the chronic vasospasm is not a primary event but a secondary phenomenon following an injury to the cerebral arterial wall.

알루미늄-크롬 용융도금강판의 미세조직과 집합조직에 미치는 크롬의 영향

임병문,홍승현,정재인,최장현,정원섭 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.10

Microstructure and texture changes of aluminized coatings on steel sheets having Cr ranging from 0.0% to 1.0% in the coated layer were investigated. The surface morphology of the Al-Cr coated steel is not influenced by the increase of Cr contents in the coated layer. While the coated layer of aluminized steel consisted of two phases of Al and Al_(5)Fe₂, the aluminized coating layer containing Cr was composed of three phases of Al, Al_(13)Cr₂, and Al_(13)Fe₄+Al_(5)Fe₂. The surface layer was Al, the middle layer was Al_(13)Cr₂, and the interfacial layer between the coating and the steel substrate was Al_(13)Fe₄and Al_(5)Fe₂. The texture of the aluminized coating without Cr was characterized as a {001} fiber texture which major orientation was {001}<110>. As the Cr content in the aluminized layer was increased to 1.0%, the texture of the aluminized coating was not changed but the intensity of the {001} fiber texture was increased. The major orientation in the {001} fiber texture was changed from the rotated cube orientation of the aluminized coating with 0.1%Cr to the cube orientation of the aluminized coating with 1.0%Cr.

과학 실험·실습의 지도평가를 위한 모형과 도구개발

고재걸,민경덕,최종락,오대섭,권병규,변창진,여환진,정원우 경북대학교 과학교육연구소 1988 科學敎育硏究誌 Vol.12 No.-

The purpose of this study is to develop models and instruments for teaching and assessing scientific experiments and practices. General objectives for teaching and evaluating scientific experiments and practices in secondary schools were analyzed and categorized into three domains:they were inquiry skill, scientific thinking skill, and scientific attitude. The sub-categories for each domain were constructed, and specific objectives for each general objective were also stated in terms of behavioral objectives according to Mager's suggestion. The tables of specification (content×behavior) were developed in order to assist secondary school teachers to teach and evaluate scientific experiments in class. In addition, we introduced some useful assessment techniques which can be adopted to evaluating learning outcomes of each specific objective. The sample test items corresponding to each objective were listed for practical usage in class.