• Journal of Urban Science
• /
• v.9 no.2
• /
• pp.45-50
• /
• 2020

The formation characteristics of calcium carbonates are closely related to the durability and mechanical properties of cement-based materials. In this regard, a deep understanding of the reaction pathway of calcium carbonates is critical. Recently, non-classical nucleation theory was summarized and it was presumed that prenucleation clusters are present. The formation of the prenucleation cluster at undersaturated condition (≈ 0.1 ml) in the present study was investigated via electrical characteristics of an electrolytic solution. Calcium chloride dihydrate (CaCl2·2H2O) and sodium carbonate (Na2CO3) were used as starting materials to supply calcium and carbonate sources, respectively. Furthermore, the reaction pathway of calcium carbonates was investigated by time-resolved polarization and depolarization characteristics of the electrolytic solution. The time-resolved polarization and depolarization tests were conducted by switching polarity with an interval of 20 seconds for 1 hr and by measuring the variation of electrical resistance. It can be inferred from the results obtained in the present study that the reactive constituent for the formation of calcium carbonates was mostly consumed in the period possibly associated with the prenucleation and the reaction pathways may be governed by the monomer-addition mechanism.

• The Korean Journal of Physiology
• /
• v.1 no.1
• /
• pp.7-22
• /
• 1967

인간(人間)의 감각(感覺), 운동(運動), 사고등(思考等)에 직접관여(直接關與)하는 체성신경원(體性神經元)이 인체내(人體內)에 있어서 단일세포동물(單一細胞動物)과 비체성신경원(非體性神經元)과 같이 각종(各種)의 자극(刺戟)에 직접응(直接應)하므로써 기능적(機能的) 활동(活動)을 개시(開始)한다는 한연(漢然)한 예상하(豫想下)에서 말초(末梢)에서는 혹종(或種)의 통소(痛素)를, 중추(中樞)에서는 어떤 묘(妙)한 화학적(化學約)인 흥분전달물질(興奮傳達物質)을 탐구(探求)하고 있으며 말초(末梢)의 통흥분시발(痛興奮始發)과 대뇌피질(大腦皮質)의 기능발생(機能發生)같은 중요(重要)한 제기전(諸機轉)이 해명(解明)될 가능성(可能性)조차 보이지 않는 것이 체성신경생리학(體性神經生理學)의 현상(現狀)이다. 저자(著者)는 생태분리(生態分離)한 단일신경섬유실험(單一神經纖維實驗)과 임상적연구(臨床的硏究)로서 인체내(人體內)의 체성신경섬유(體性神經纖維)와 그 구심성종말(求心性終末)은 최종(最終) 공통기계적자극(共通機械的刺戟)을 받는 점(點)을 입증(立證)하고 뇌피질내(腦皮質內)의 입사(入射)에 의(依)한 Synapse 전달(傳達)이 기계적(機械的)인 점(點)과 모세혈관확대(毛細血管擴大)에 의(依)한 Glial Satellite 부(部)의 기계적전달(機械的傳達)과 Spine Koph 에서는 입사(入射) 없이도 Massage에 의(依)하여 초발탈분극(初發脫分極)이 발생(發生)될 필연성(必然性)을 지적(指摘)하는 동시(同時)에 저자(著者)가 부르는 ${\ulcorner}$체성신경계(體性神經系)의 기계적생리학(機械的生理學)${\lrcorner}$에 의(依)하면 난간(難間)에 속(屬)하는 대다수(大多數)의 신경현상(神經現象)과 정신현상(精神現象)이 구체적(具體的)이며 합리적(合理的)이요 또 실용적(實用的)으로 해명(解明)됨을 실례(實例)를 들어서 예시(例示)한다. 본연구(本硏究)는 습수만예(拾數萬例)의 단일신경섬유관찰(單一神經纖維觀察)과 수백예(數百例)의 임상적연구(臨床的硏究)와 최근고도(最近高度)로 발달(發達)된 기술(技術)에 의(依)한 징소생리학적(徵少生理學的) 제연구업속(諸硏究業續)과 전자현미경적형태학성과(電子顯徵鏡的形態學成果)를 종합(綜合)하므로써 성립(成立)된 것이요 하등(何等)적 무리(無理)한 억측(憶測)을 내포(內包)하지 않음을 확신(確信)한다.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.27 no.3
• /
• pp.400-409
• /
• 2000

This study used in vivo intracellular and extracellular field potential recording to evaluate the intrinsic membrane properties and connection pattern within facial nucleus. 1. There were four subdivisions of medial, intermediate, lateral, and dorsolateral in facial nucleus. 2. Principal cells in the facial nucleus was recorded from and filled with neurobiotin in anesthetized rats. The extent of their dendrites and the characteristics of cell body were examined. 3. Principal cells had a large amplitude action potential and afterhyperpolarization was followed a single action potential. 4. The response from facial motonucleus to electrical stimulation of the facial nerve was mainly a monophasic wave, with a latency of 1 msec, which was assumed to reflect antidromic activation of facial motoneurons. In some of rats the response in addition showed late components at a latency of about 7-8 msec, but its amplitude was small. 5 Most of cells exhibited accommodation of spike discharge upon depolarization of membrane by 0.8 nA for 400 ms. Our results support the hypothesis that there normally are weak connections between different parts of the facial motonucleus to explain pathophysiology of hemifacial spasm and facial naive paralysis.

• Journal of Embryo Transfer
• /
• v.21 no.1
• /
• pp.35-43
• /
• 2006

Ions play important roles in various cellular processes including fertilization and differentiation. However, it is little known whether how ions are regulated during early embryonic development in mammalian animals. In this study, we examined changes in $Ca^{2+}\;and\;K^+$ concentrations in embryos and oviduct during mouse early embryonic development using patch clamp technique and confocal laser scanning microscopy. The intracellular calcium concentration in each stage embryos did not markedly change. At 56h afier hCG injection when 8-cell embryos could be Isolated from oviduct, $K^+$ concentration in oviduct increased by 26% compared with that at 14h after injection of hCG During early embryonic development, membrane potential was depolarized (from -38 mV to -16 mV), and $Ca^{2+}$ currents decreased, indicating that some $K^+$ channel might control membrane potential in oocytes. To record the changes in membrane potential induced by influx of $Ca^{2+}$ in mouse oocytes, we applied 5 mM $Ca^{2+}$ to the bath solution. The membrane potential transiently hyperpolarized and then recovered. In order to classify $K^+$ channels that cause hyperpolarization, we first applied TEA and apamin, general $K^+$ channel blockers, to the bath solution. Interestingly, the hyperpolarization of membrane potential still appeared in oocytes pretreated with TEA and apamin. This result suggest that the $K^+$ channel that induces hyperpolarization could belong to another $K^+$ channel such as two-pore domain $K^+(K_{2P})$channel that a.e insensitive to TEA and apamin. From these results, we suggest that the changes in $Ca^{2+}\;and\;K^+$ concentrations play a critical role in cell proliferation, differentiation and reproduction as well as early embryonic development, and $K_{2P}$ channels could be involved in regulation of membrane potential in ovulated oocytes.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.10
• /
• pp.1317-1323
• /
• 2009

In the present study, we investigated the anti-proliferation activity of Citrus grandis Osbeck peel (CGP) in HL60 (human promyelocytic leukemia) cells. It was found that 80% ethanol extract of CGP could inhibit the cell growth in a dose-dependent manner ($250{\sim}1,000{\mu}g/mL$), which was associated with morphological changes and apoptotic cell death such as depolarized mitochondrial membrane, formation of apoptotic bodies and increased populations of apoptotic sub-G1 phase. The results indicate that CGP extract inhibits the growth of HL60 cancer cells by the induction of apoptosis, which may be mediated by its ability to change the Bcl family proteins and increase the activation of caspase-3 and PARP. Therefore, it is suggested that CGP has the potential to provide a remarkable natural defense against the proliferation of HL60 cells.