• 한국발생생물학회지:발생과생식
• /
• 제15권1호
• /
• pp.31-39
• /
• 2011

Change in intracellular $Ca^{2+}$-concentration ($[Ca^{2+}]_i$) is an essential event for egg activation and further development. $Ca^{2+}$ ion is originated from intracellular $Ca^{2+}$-store via inositol 1,4,5-triphosphate receptor and/or $Ca^{2+}$ influx via $Ca^{2+}$ channel. This study was performed to investigate whether changes in $Ca^{2+}$/calmodulin dependent protein kinase II (CaM KII) activity affect $Ca^{2+}$ influx during artificial egg activation with ethanol using $Ca^{2+}$ monitoring system and whole-cell patch clamp technique. Under $Ca^{2+}$ ion-omitted condition, $Ca^{2+}$-oscillation was stopped within 30 min post microinjection of porcine sperm factor, and ethanol-induced $Ca^{2+}$ increase was reduced. To investigate the role of CaM KII known as an integrator of $Ca^{2+}$- oscillation during mammalian egg fertilization, CaM KII activity was tested with a specific inhibitor KN-93. In the eggs treated with KN-93, ethanol failed to induce egg activation. In addition, KN-93 inhibited inward $Ca^{2+}$ current ($I_{Ca}$) in a time-dependent manner in whole-cell configuration. Immunostaining data showed that the voltage-dependent $Ca^{2+}$ channels were distributed along the plasma membrane of mouse egg and 2-cell embryo. From these results, we suggest that $Ca^{2+}$ influx during fertilization might be controlled by CaM KII activity.

• 한국주조공학회지
• /
• 제26권3호
• /
• pp.146-151
• /
• 2006

In this study, effects of CaD and Ca addtions on microstructure and ignition resistance of pure Mg were investigated. With increasing Ca and CaO contents, the grains in Ca and CaO added Mg were refined and ignition temperatures of CaO and Ca added Mg increased, too. As a result of phase analysis, CaO seemed to be reduced to Ca. $Mg_2Ca$ phase was formed even in 0.1 wt%CaO added pure Mg by reduction mechanism, while $Mg_2Ca$ phase was formed in over 1.35 wt% Ca added pure Mg. Thermodynamical consideration for the reduction mechanism of CaO in pure Mg was carried out.

• Biomolecules & Therapeutics
• /
• 제15권4호
• /
• pp.212-217
• /
• 2007

In atrial myocytes, lacking t-tubules, $Ca^{2+}$ current ($I_{Ca}$)-initiated $Ca^{2+}$ release at the peripheral junctional sites propagates into the interior of the cell by diffusion of $Ca^{2+}$. We have previously reported that time of activation of the central sites is independent of $I_{Ca}$. In the present study we have probed the effects of Bay K 8644 on $Ca^{2+}$ propagation wave to the center of the myocyte using rapid 2-D confocal $Ca^{2+}$ imaging in the rat atrial myocytes. Enhancement of $I_{Ca}$ by Bay K 8644 accelerated the rate of peripheral $Ca^{2+}$ release, but did not affect the speed of propagation of central release. In contrast, enhancement of $I_{Ca}$ by intracellular cAMP reduced the magnitude of peripheral and central $Ca^{2+}$ transients, but significantly accelerated the speed of central $Ca^{2+}$ release. Our data suggest that the speed of central $Ca^{2+}$ propagation triggered by $I_{Ca}$ is not regulated by the magnitude of either $I_{Ca}$ or local cytosolic $Ca^{2+}$ releases.

• 분석과학
• /
• 제24권6호
• /
• pp.527-532
• /
• 2011

IQGAP1은 세포 내에서 암세포화, 세포이동과 같은 다양한 기능을 수행하고 있으며, $Ca^{2+}$-비의존성 calmodulin (CaM) 결합 단백질로 잘 알려져 있다. IQGAP1내에는 IQ부위가 4 번 반복해서 나타나는데, 이 부위가 IQGAP1의 CaM 결합에 중요한 역할을 한다고 알려져 있다. 이전의 연구를 통해 4개의 IQ 부위 모두 $Ca^{2+}$/CaM과의 결합에 관여하고, IQ3와 IQ4는 $Ca^{2+}$이 결합되지 않는 상태의 CaM인 proCaM 결합에 관여 한다고 알려져 있다. 그러나, 이러한 각각의 IQ 부위와의 결합성이 CaM과 직접적인 결합인지, 아니면 다른 단백질이 매개하는 간접적인 결합인지 알려져 있지 않았다. 따라서, 본 연구에서는 IQGAP1의 각각의 IQ 부위와 CaM의 결합성을 직접적으로 알아보기 의해 in vitro에서 조사해 보았다. 그 결과, 흥미롭게도 이전의 결과와는 다르게 4개의 IQ 부위 중에서 IQ3는 의미있는 $Ca^{2+}$-비의존성 CaM결합성이 있음을 알게 되었고, IQ1는 약한 $Ca^{2+}$-의존성 CaM 결합성이 있음을 알게 되었다. 반면에, 다른 IQ 부위들은 CaM과의 결합력이 약하거나 없음을 확인하였다. 또한, 기존의 IQ 부위 이외에 IQ(2.7-3)과 IQ(3.5-4.4) 부위가 의미있는 CaM 결합성이 있음을 확인하게 되었다. 따라서, 본 연구 결과 CaM이 IQGAP1을 기존의 보고와는 다른 방식으로 조절할 수 있을 가능성이 있음을 알게 되었고, 새로운 결합 부위 동정을 통해 IQGAP1과 CaM의 결합이 미치는 생리학적인 의미를 연구할 수 있는 토대를 마련하였다.

• Journal of Nutrition and Health
• /
• 제31권4호
• /
• pp.716-728
• /
• 1998

To investigate the effect of dietary Ca levels on metabolic changes of Ca and skeleton in postmenopausal women, 10-month-old ovariectomized female rats were compared with 2 month old rats. The rats were fed either 0.2% or 1.2% Ca diets for 16 weeks. Food intake and weight gain as higher in rats fed high Ca diets and in ovariectomized rats. Apparent Ca absorption as higher, and Ca balance was lower in the low Ca groups. Vertebrae density was higher in old rats or those fed a high Ca diets. The old rats and ovariectomized rats showed decreased bone formation, increased bone resorption and kidney function deterioration resulting in increased urinary Ca excretion. Contradictory to the above observation, old rats and ovariectomized rats still showed higher bone mass and bone ash content. Therefore aging was not fully onging in 10-month-old rats. Bone weights, mineral contents, and mineral/wt ratio were lower in ovariectomized rats. Dietary Ca level did not affect urinary Ca excretion, urinary protein excretion, GFR, serum alkaline phosphatase, or urinary hydroxyporline excretion. This means that dietary Ca level did not influence kidney function or bone turnover. However Ca content and the ash content of femur, 4th vertebra, and scapula were increased in high Ca groups. Therefore, it is considered that decreased bone formation and accelerated bone resorption may account for the increased osteoporotic risk in women in menopause after middle age. However, Ca metabolism can be improved and bone components can be maintained if Ca is supplemented.

• 한국유기농업학회지
• /
• 제18권3호
• /
• pp.377-386
• /
• 2010

`부유' 단감은 주로 MA를 통해서 저장되지만, 저장기간 동안 과육의 과정부 갈변과 과피 흡변을 가져와서 과실의 품질을 저하시킨다. 칼슘은 세포막에 중요한 역할을 하며 칼슘과 관련된 과실 생리장해를 경감시킨다. 본 연구는 수용성 칼슘 관주와 엽면살포가 토양의 화학성, 근활력 그리고 엽 내 무기성분에 어떠한 영향을 미치는지에 에 대해서 조사하였다. 칼슘 관주(Ca-FG)와 칼슘과 IBA를 혼용한 관주(Ca+IBA)처리는 대조구(Cont), 칼슘 엽면살포(Ca-FA), 그리고 IBA관주처리 (IBA)보다 높은 토양 칼슘함량을 보였으며, 토양 내 칼슐함량의 증가는 pH를 상승시키는 경향을 보였다. Ca+IBA처리는 근활력을 증가시켰다. 엽내 칼슘은 CA-FA에 증가되었고, Ca+IBA와 Ca-FG에 의해서도 증가하는 경향이 나타났다.

• Journal of Nutrition and Health
• /
• 제40권5호
• /
• pp.419-427
• /
• 2007

This study explored the effects of dietary calcium level and Hijikia fusiforme supplementation on bone indices and serum lipid levels using 36 female Sprague-Dawley rats as a model. Rats received low Ca diet for 3 weeks after ovariectomy. The rats were then divided into six dietary groups and fed low (0.1% Ca), normal (0.5% Ca) and high (1.5% Ca) Ca diets (CaL, CaN, CaH) and low, normal, high Ca diets with Hijikia fusiforme supplementation (CaLH, CaNH, CaHH) for 3 weeks. After each experimental periods, 24 hour urine and/or blood samples, left and right femurs were collected for analysis. Serum Ca concentration showed no significant difference by dietary Ca levels and Hijikia fusiforme supplementation. Alkaline phosphatase activity was significantly higher in normal and high Ca group compared to low Ca group. Serum total cholesterol, triglyceride and total lipid were not significantly different among groups. HDL-cholesterol showed no significant difference by Hijikia fusiforme supplementation. However, the normal and high Ca groups showed significantly higher HDL-cholesterol compared to the low Ca group. Urinary hydroxyproline and hydroxyproline/creatinine ratio were not significantly different among groups. The wet weight of the femur was significantly higher in low Ca group compared to normal or high Ca group. The dry weight, wet weight/body weight, length and breaking force of the femur were not significantly different among groups. Ash contents/wet weight of the femur was significantly increased as dietary Ca levels up and significantly higher in Hijikia fusiforme supplementation groups. The Ca content of the femur were significantly higher in the normal and high Ca groups than the low Ca group. However, there was no significant difference in Ca content by Hijikia fusiforme supplementation.

• 한국통신학회논문지
• /
• 제18권8호
• /
• pp.1102-1107
• /
• 1993

CaO-TiO2 이성분계에서 40~50 mol% CaO 조성범위를 선택하여 CaTiO3과 CaTiO3-TiO2세라믹스의 마이크로파 유전특성을 조사하였다. CaTiO3 단일상 (50 mol% CaO조성)일 때 유전율(er) 178, 공진주파수 (fo)의 온도계수(r,)+1000ppm/C, 픔질계수인 Q값 2760(fo=2.7 GHz)으로 가장 큰 값을 나타내었다. CaTiO3와 TiO2상이 혼합상으로 있는 유전체에서는 CaO 함량이 감소함에 따라서 유전율과 공진주파수의 온도계수는 점차 감소하였으나 Q값과 밀도는 47 mol% CaO조성에서 가장 낮았다. 이것은 이상 혼합 세라믹에서 TiO2상의 감소로 인해 CaTiO3의 결정립 성장이 급속하게 일어남으로써 입계와 입내에 큰 기공이 존재하지 때문으로 생각된다.

• 한국식품영양과학회지
• /
• 제28권3호
• /
• pp.677-684
• /
• 1999

This study has dealt the effect of Ca regulating hormones and dietary Ca levels on Ca metabolism. Animals(BALB/c mice) were divided into three dietary groups(high and medium Ca and Ca free) and hormones including parathyroid hormone(PTH), calcitonin(CT), cholecalciferol(Vit D) were i.p. injected. After feeding experimental diets for five weeks, mice were anaethetized and sacrificed by heart puncture. We found that femur growth of mouse was slightly increased by high dietary Ca without showing statistical significance comparing to low dietary Ca group. The combination of PTH and CT showed the same effect when dietary Ca was high. At the same time, total mineral retention in bone was most affected by dietary Ca. In general, high Ca diet elevated Ca level in the serum. When dietary Ca was low, PTH stimulated Ca release from the bone into the serum, which was shown to be inhibited by CT treatment. Comparing to the control, PTH, Vit D and CT together tended to inhibit serum Ca level at high and medium dietary Ca. PTH and Vit D inhibited Ca reserve in the liver at all dietary levels of Ca. Both PTH and Vit D stimulated bone Ca retention when dietary Ca was low, but this effect was reversed when dietary Ca was high. When PTH, Vit D and CT were administered together, bone Ca level was greatly enhanced at low dietary Ca than at high dietary Ca, which suggests that these hormonal cooperation is needed for proper bone density maintenance especially when dietary minerals are not sufficient.

• 한국통신학회논문지
• /
• 제39A권9호
• /
• pp.497-507
• /
• 2014

본 논문은 3GPP REL-12 에서 논의하는 반송파 집성(Carrier aggregation, CA) 기술의 표준 동향, 이를 지원하기 위한 단말요구 사항 정의, 그리고 이를 바탕으로 예측한 향후 기술 발전의 방향에 관한 것이다. 이는 REL-12에서 논의되는 상향 링크(Uplink, UL)에서의 2UL CA, 하향 링크(Downlink, DL)에서 3개의 반송파를 집성하는 3DL CA, TDD와 FDD를 결합하는 TDD-FDD CA 등이 포함되며, 또한 단말 RF 단에서 필요한 공존 이슈, 대역외 방사 이슈를 비롯한 여러 RF 요구사항을 분석 및 실험 결과들을 포함한다. 또한 CA 진화의 한 축인 비면허 대역과 LTE 운용 주파수 대역과의 반송파 집성기술인 LTE-U를 포함한 CA 진화 방향에 대해서도 기술한다.