• The Korean Journal of Physiology
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• 제24권2호
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• pp.281-291
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• 1990

The $Ca^{2+}-substitutional$ roles of strontium for the contractile processes were investigated in the rabbit renal artery. The contractions induced by either norepinephrine or high $K^+$ in the condition which intra- and extracellular $Ca^{2+}$ were replaced by $Sr^{2+}$, i.e. $Sr^{2+}-mediated$ contractions, were dose-dependent. And then the maximal amplitude of contraction, as compared with $Ca^{2+}-mediated$ contraction, was about 50% in norepinephrine and about 70% in high $K^+$. The $Sr^{2+}-mediated$ contractions were independent in the contraction by norepinephrine $(10^{-5}M)$ but dependent in those by high $K^+(100\;mM)$ on the extracellular $Sr^{2+}$ concentration. Also $Sr^{2+}-mediated$ contractions induced by norepinephrine were observed in the $Sr^{2+}-free$ Tyrode's solution. The $Sr^{2+}-mediated$ contractions induced by either norepinephrine or high $K^+$ were suppressed by verapamil, a $Ca^{2+}-channel$ blocker. By extracellular addition of $Sr^{2+}$, the $Ca^{2+}-mediated$ contractions induced by norepinephrine $(10^{-5}M)$ or 40 mM $K^+$ were inhibited but those by high $K^+(100\;mM)$ were increased. And the $Sr^{2+}-mediated$ contractions were increased by extracellular addition of $Ca^{2+}$ but did not reach the level of $Ca^{2+}-mediated$ contraction. Therfore it is suggested that in the vascular smooth muscle of rabbit renal artery $Sr^{2+}$ could enter the smooth muscle cells easily through the potential-operated calcium channel (POC) but not easily through the receptor-operated calcium channel (ROG), and $Sr^{2+}$ might be stored in the intracellular $Ca^{2+}-binding$ site and released by NE and induced the contraction by a way of activating directly the contractile apparatus.

• 분석과학
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• 제18권6호
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• pp.469-474
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• 2005

본 연구에서는 음이온 교환수지와 Sr-Spec 수지를 사용하여 토양중 $^{90}Sr$, $^{241}Am$ 및 Pu 동위원소들에 대하여 축차적으로 분리하는 정량법을 제시하였다. 플루토늄은 음이온 교환수지를 이용하여 분리하였고, 아메리슘 및 스트론튬은 옥살산 공침법 및 Sr-Spec 수지를 사용하여 순수 분리하였다. Pu 및 Am 동위원소는 알파 스펙트로메트리법으로 정량하였고, Sr-90은 액체섬광계수기를 사용하여 정량하였다. 본 연구에서 고찰된 $^{90}Sr$, $^{241}Am$ 및 Pu 동위원소 분석법을 IAEA 기준시료에 적용하여 분석법의 타당성을 검증하였다.

• 한국재료학회지
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• 제20권3호
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• pp.155-160
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• 2010

In this study, we investigated primary biocompatibility and osteogenic gene expression of porous granular BCP bone substitutes with or without strontium (Sr) doping. In vitro biocompatibility was investigated on fibroblasts like L929 cells and osteoblasts like MG-63 cells using a cell viability assay (MTT) and one cell morphological observation by SEM, respectively. MTT results showed a cell viability percent of L929 fibroblasts, which was higher in Sr-BCP granules (98-101%) than in the non-doped granules (92-96%, p < 0.05). Osteoblasts like MG-63 cells were also found to proliferate better on Sr-doped BCP granules (01-111%) than on the non-doped ones (92-99%, p < 0.05) using an MTT assay. As compared with pure BCP granules, SEM images of MG-63 cells grown on sample surfaces confirmed that cellular spreading, adhesion and proliferation were facilitated by Sr doping on BCP. Active filopodial growth of MG-63 cells was also observed on Sr-doped BCP granules. The cells on Sr-doped BCP granules were well attached and spread out. Gene expression of osteonectin, osteopontin and osteoprotegrin were also evaluated using reverse transcriptase polymerase chain reaction (RT-PCR), which showed that the mRNA phenotypes of these genes were well maintained and expressed in Sr-doped BCP granules. These results suggest that Sr doping in a porous BCP granule can potentially enhance the biocompatibility and bone ingrowth capability of BCP biomaterials.

• 한국세라믹학회지
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• 제52권6호
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• pp.467-472
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• 2015

The effect of $SrCO_3$ content on the microstructure, porosity, flexural strength, and pore size distribution of clay-based membrane supports was investigated. Green compacts prepared from low cost materials such as kaolin, bentonite, talc, sodium borate, and strontium carbonate were sintered at $1000^{\circ}C$ for 8 h in air. It was possible to control the porosity of the clay-based membrane supports within the range of 33% to 37% by adjusting the $SrCO_3$ content. The flexural strength of the clay-based membrane supports was found to strongly depend on their porosity. In turn, the porosity was affected by the $SrCO_3$ content. The average pore size and flexural strength of the clay-based membrane supports containing 4 wt% $SrCO_3$ were $0.62{\mu}m$ and 33 MPa at 34% porosity.

• 한국해양학회지
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• 제10권1호
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• pp.25-32
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• 1975

Continued to the previous paper, the present investigation deals with stronitium-90 activities and calcium contents among 54 samples of edible marine algae collected along the coast of Korea during September, 1973 and April, 1974. The calcium contents are variable 2.0-17.8%, and 6.38% on an average. Most of the members investigated contain 2-4% in green and red algae, and 8-10% in brown algae. Strontium-90 activities are 0.32-0.37 pCi/l in sea-water, and 0.80-28.66 pCi$\^$90/Sr/g Ca in edible seaweeds. Among the algal phyla, they are 12.49 in green, 3.34 in brown, and 9.39 pCi$\^$90/Sr/g Ca in red algae, while they are 6.25 pCi$\^$90/Sr/g Ca on an average. In a single species collected at the same season, the highest activities appear mostly from the eastern coast, and from the western and southern coasts, in turn. The green algae, Capsosiphon- Enteromorpha complex show about 3 times higher activities, 28.66 pCi$\^$90/Sr /g Ca compared with the other members showing rather higher activities, and would be an indicator plant of strontium-90 activities of the marine algae along the coast of Korea.

• Journal of Periodontal and Implant Science
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• 제39권1호
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• pp.9-16
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• 2009

Purpose: The present study was performed to evaluate the effect of hydroxyapatite dental paste on tooth hypersensitivity compared to other materials. Materials and methods: In the general fluoride dental paste, strontium fluoride dental paste and hydroxyapatite dental paste, patient-performed VAS and VAS(ice test) were measured at baseline, 1weeks and 4weeks. Results: 1. In patient-performed VAS, there were significant differences reducing of tooth hypersensitivity between general fluoride toothpaste and hydroxyapatite toothpaste. 2. In operator-performed VAS(ice test), there were significant differences reducing of tooth hypersensitivity among each group, between general fluoride toothpaste and hydroxyapatite toothpaste and between general fluoride toothpaste and strontium fluoride toothpaste. Conclusion: In conclusion, hydroxyapatite toothpaste can be applied for control of tooth hypersensitivity.

• Journal of Radiation Protection and Research
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• 제24권3호
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• pp.155-160
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• 1999

환경 중에는 핵실험 및 원자력 발전소에서 방출되는 여러 가지 방사성 핵종들과 천연방사성 핵종들이 존재한다. 이 중에서 원자력발전소 운영과 관련하여, 환경 중의 인공방사성 핵종에 대한 관심이 높아지고 있다. 핵실험이나 원자력발전소와 관련된 인공방사선 핵종들은 주로 핵분열 생성물들로서, 그 수가 200여종에 이른다. 이 중에서도 $^{90}Sr$과 $^{137}Cs$은 선량특성상 특히 주목되어 왔다. 본 논문에서는 환경준위의 $^{90}Sr$ 정량 분석 방법에 대한 연구를 수행하였다. 환경 중의 $^{90}Sr$은 저준위이며, 특성 감마선과는 달리 연속 스팩트럼의 베타선원으로, $^{89}Sr$, $^{90}Y$ 및 다른 방사성 핵종들과 혼합되어 있기 때문에 정량적인 분석이 매우 어렵다. 저준위 방사성 스트론튬 분석을 위해서는 농축 과정 및 분석에 영향을 주는 타 방사성 핵종과의 화학적 분리과정이 필요하다. 그 동안 국내 여러 기관에서 공통적으로 스트론튬 회수율 산정을 위해 중량법을 사용하였고, 화학분리절차도 중량법을 사용하기에 적합하도록 개발하여 사용하였다. 최근 분석기기의 발달로 인해서, ppm 이나 ppb 단위의 안정원소 분석을 쉽게 할 수 있다는 점에 근거하여, 원자분광분석기기(ICP : Inductively Coupled atomic Plasma emission spectrophotometer)를 사용한 회수율 산정 및 그에 적합한 절차를 개발하였다. 개발된 절차는 기존의 중량법에 비해서 화학적 처리절차가 훨씬 간편하면서도 정확도가 높아서, 환경방사성 스트론튬의 정량분석에 적절히 사용될 수 있다.

• 한국막학회:학술대회논문집
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• 한국막학회 2001년도 추계 총회 및 학술발표회(한국막학회)
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• pp.123-126
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• 2001

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2013년도 자성 및 자성재료 국제학술대회
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• pp.161-161
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• 2013

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 추계학술발표회요약집
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• pp.289.1-289
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• 2001