• Restorative Dentistry and Endodontics
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• 제35권5호
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• pp.359-367
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• 2010

연구목적: 본 연구의 목적은 glass ionomer cement (GIC)와 혼합된 mineral trioxide aggregate (MTA)의 생체친화성을 평가하고 이것을 MTA, GIC, IRM, SuperEBA와 비교해보는 것이다. 연구 재료 및 방법: 재료의 세포독성을 평가하기 위해 MG-63세포를 이용해 주사전자 현미경 관찰과 XTT assay를 실시하였다. 결과: 주사전자 현미경 관찰에서는 GIC와 혼합한 MTA, MTA, GIC의 표면에서 세포질 돌기를 가진 많은 세포들이 밀집되고 융합된 형태로 관찰되었다. 반면 IRM과 SuperEBA에서는 세포들의 수가 적고 둥근 양상을 보여주었다. XTT assay에서는 GIC와 혼합한 MTA에서의 세포 활성도는 모든 시점에서 MTA 또는 GIC와 유사하였다. 반면 IRM과 SuperEBA에서는 모든 시점에서 세포활성도가 다른 그룹에 비해 유의하게 더 낮았다. 결론: 본 연구에서 GIC와 혼합된 MTA는 MTA, GIC와 유사한 세포 반응을 나타냈다. 이것은 GIC와 혼합된 MTA가 MTA, GIC와 마찬가지로 좋은 생체친화성을 가진 재료라는 것을 시사한다.

• 대한전자공학회논문지
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• 제9권3호
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• pp.9-16
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• 1972

본논문은 "s"를 변환함수로 하는 GIC회로가 자이레이터와 마찬가지로 인덕터를 RC능동회로로서 실헐할 수 있고, 또 임의의 안정한 전달함수가 GIC를 포함한 2단자대회로의 open-circuit voltage ratio로서 실현될 수 있음을 밝힌 것이다. 트랜지스터를 사용하여 GIC회로를 구성함에 있어시 트랜지스터의 nullator-norator model이 적어도 10kHz 이하의 주파수 범위에서 훌륭하게 적용될 수 있음이 밝혀졌다. GIC를 사용한 회로합성법의 특징은 다음괴 같다. 첫째로, 임의의 안정한 전달함수는 대단히 단순한 회로구성을 되풀이함으로서 체계계적으로 또 기계적으로 실현될 수 있다. 둘째로, 전체 회로에 있어서 GIC를 제외한 모든 회로요소는 저항뿐이다. 셋째로 n차의 전달함수를 실현하는데 있어서 필요한 콘덴서의 수효는 n이며, 이것은 가능한 가장 적은 수효라고 믿어진다.

• 공업화학
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• 제9권5호
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• pp.786-790
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• 1998

리튬이온이차전지에 사용되는 탄소부극의 성능을 향상시키기 위하여 새로운 탄소부극으로서 K-GIC를 합성하여 전기화학적 특성을 조사하였다. K의 삽입량은 KCl 수용액의 농도가 $2>3>1mole/{\ell}$의 순으로 증가하였으며 $1mole/{\ell}$의 KCl 수용액으로 처리하였을 때 K와 C의 mole 비는 156~388 carbon/potassium이었다. K-GIC의 합성조건을 $1mole/{\ell}$ KCl 수용액으로 $700^{\circ}C$에서 1시간으로 처리하였을 때 가장 우수한 리튬의 삽입과 탈삽입 거동을 나타냈으며 가역성 또한 우수하였다.

• Restorative Dentistry and Endodontics
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• 제35권5호
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• pp.344-352
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• 2010

연구목적: 본 연구의 목적은 glass ionomer cement (GIC)와 혼합한 mineral trioxide aggregate (MTA)의 경화 시간, 압축 강도, 용해도, pH를 평가하고 이것을 MTA, GIC, IRM, SuperEBA와 비교하는 것이다. 연구 재료 및 방법: 경화 시간과 압축 강도는 ISO 9917, 그리고 용해도는 ISO 6876 기준에 따라 측정하였다. pH는 고체시편 전용 전극이 연결된 pH meter를 이용하여 측정하였다. 결과: GIC와 혼합한 MTA의 경화시간은 MTA보다 유의하게 짧았으며 압축 강도는 7일간 모든 시점에서 다른 재료보다 유의하게 낮았다. GIC와 혼합한 MTA 중에서 1 : 1과 2 : 1 시편의 용해도는 다른 실험군보다 유의하게 높았다. 또한 GIC와 혼합한 MTA의 pH는 혼합직후 2-4의 범위에서 1일 후 5-7 사이로 증가하였다. 결론: GIC와 혼합한 MTA의 경화시간은 MTA에 비해 개선되었으나 압축강도 및 pH와 같은 다른 성질들은 MTA에 비해 오히려 열등한 것으로 밝혀졌다. 임상적 사용이 가능하려면, MTA의 기존 장점을 저해하지 않으면서 단점을 개선하기 위한 적절한 혼합비를 찾아내고 생체친화성을 평가하는 추가적인 연구가 필수적이다.

• 조명전기설비학회논문지
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• 제26권12호
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• pp.56-61
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• 2012

There have been a lot of reports about the effects of geomagnetically induced current(GIC) on the power grids. However there has been little domestic efforts made in this relatively urgent area which include academic research or risk assessments on GIC. There still exist a claim that domestic power grids might be in the safe state from GIC since our geomagnetic latitude is low and our power grid is relatively small scale. However it has been already demonstrated that GIC has an effect on power grids located at all latitudes. In this study, we have reviewed the transpiratory principle of the GIC, case studies of the major damage in various regions and we have calculated the GIC that can occur in domestic power grids. This paper presents some of the fundamental information about the risk assessment of domestic power grids from GIC although more thorough investigation should be made to ensure the safe operation of nationwide electric power infrastructure.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1999년도 한국생물과학협회 학술발표대회
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• pp.11-11
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• 1999

;It has been reported that suspension-cultured rice cells grown on mixed carbon sources of glucose (GIc) and acetate exhibited diauxic growth in which acetate was the preferred carbon source (Lee and Lee, 1996). Carrot (Daucus carota L.) suspension cells, showing a diauxic growth very similar to that of rice cells, were used to delineate the mechanisms underlying this preferential use of acetate over GIc. Uptakes of both GIc and 3-0-methylglucose (3-0MG), a non-metabolizable GIc analogue, were similarly inhibited when acetate or butylate, weak acids which are capable of transporting protons into the cytosol, were present in the uptake assay mixture containing cells harvested during the GIc-utilizing second growth phase. Inhibition of GIc uptake by these weak acids was similar when equivalent experiments were carried out with isolated plasma membranes. It was further shown that Glc uptake, which requires a proper proton gradient across the plasma membranes, was inhibited during the first growth phase by acetate-mediated alkalization of growth medium and/or simultaneous acidification of cytosol. This study strongly suggests that Glc utilization in plant cells is inhibited by co-presenting carbon source(s) which can alter the proton gradient across the plasma membrane. We further examined diauxic growth in culture containing GIc and malate. Unlike the case in the culture with GIc and acetate, carrot cells used GIc first. Malate was utilized only after Glc is depleted from medium. These results indicate that GIc can be a preferred or less-preferred carbon source depending on the competing carbon source. It was noted that malate was not directly taken up by cells. Instead it was converted extracellularly into fumarate which was subsequently transported into cells. During the malate-growth phase malate uptake was negligible, and fumarate uptake was active and pH-sensitive. It was shown that fumarase released into medium was responsible for the extracellular conversion of malate into fumarate. An immunoblot experiments showed that fumarase antibody raised against Arabidopsis fumarase provided positive signals only in medium in malate culture, not in fumarate or GIc cultures. This study demonstrates the first example in that fumarase, a mitochondria marker enzyme, can be present in places other than mitochondria.ndria.

• Asian Pacific Journal of Cancer Prevention
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• 제17권4호
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• pp.1925-1931
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• 2016

Background: The XRCC1 protein facilitates various DNA repair pathways; single-nucleotide polymorphisms (SNPs) in this gene are associated with a risk of gastrointestinal cancer (GIC) with inconsistent results, but no data have been previously reported for the Sabah, North Borneo, population. We accordingly investigated the XRCC1 Arg194Trp and Arg399Gln SNPs in terms of GIC risk in Sabah. Materials and Methods: We performed genotyping for both SNPs for 250 GIC patients and 572 healthy volunteers using a polymerase chain reaction-restriction fragment length polymorphism approach. We validated heterozygosity and homozygosity for both SNPs using direct sequencing. Results: The presence of a variant 194Trp allele in the Arg194Trp SNP was significantly associated with a higher risk of GIC, especially with gastric and colorectal cancers. We additionally found that the variant 399Gln allele in Arg399Gln SNP was associated with a greater risk of developing gastric cancer. Our combined analysis revealed that inheritance of variant alleles in both SNPs increased the GIC risk in Sabah population. Based on our etiological analysis, we found that subjects ${\geq}50years$ and males who carrying the variant 194Trp allele, and Bajau subjects carrying the 399Gln allele had a significantly increased risk of GIC. Conclusions: Our findings suggest that inheritance of variant alleles in XRCC1 Arg194Trp and Arg399Gln SNPs may act as biomarkers for the early detection of GIC, especially for gastric and colorectal cancers in the Sabah population.

• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.443-460
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• 1998

The purpose of this study was to estimate the changes of tensile bond strength according to the difference in lining materials and lining area. Seventy non-carious extracted human molars were used in the present study, and they were randomly assigned into 2 experimental groups according to the difference in lining materials. Each experimental group was subdivided into 3 groups according to the difference in lining area. Circular cavities were prepared on the dentin surface to a diameter of 1.5mm, 2.0mm, 2.5mm and the prepared cavities were filled with Fuji II LC( Glass Ionomer Cement : GIC) or Dycal. Dentin specimens without circular cavity were used as control group. The primer and bonding agent of All-Bond 2 and composite resin (Z-100, 3M Dental Products, U. S. A.) were applied to the exposed dentin surface with or without lining. Tensile bond strengths for the experimental specimens were then measured. To examine the interface between dentin and liner & between liner and composite resin, two specimens from each group were fabricated and observed under the SEM. The results were as follows. 1. Tensile bond strength for the specimens lined with GIC was higher than that for specimens lined with Dycal. However, there was no significant difference between two groups(p>0.05). 2. Tensile bond strength for the specimens lined with GIC in a diameter of 1.5mm(GIC-1.5mm lining group) was statistically higher than that for the GIC-2.0mm lining group and GIC-2.5mm lining group(p<0.05). 3. Tensile bond strength for the specimens lined with Dycal in a diameter of 2.5mm (Dycal-2.5mm lining group)was statistically lower than that for Dycal-1.5mm lining group and Dycal-2.0mm lining group(p<0.05). 4. It was possible to observe the good adhesion of the resin composite to the GIC and the presence of a fissure between GIC and dentin all along the interface. Interfacial gaps of 7.2-$72.2{\mu}m$ between GIC and dentin were observed. The interfacial gap between GIC and dentin at the cavity base was greater. However, the gap was gradually decreased toward the occlusal portion. 5. It was possible to observe the poor adhesion of the resin composite to the Dycal. The detachment of Dycal was occurred all along the composite resin-Dycal interface, and the gaps of 2.0-$30.1{\mu}m$ were formed. In all the specimens, polymerization shrinkage of resin composite caused the detachment of Dycal from the body of Dycal. At a Dycal-dentin interface. it was possible to observe the good adhesion. but poor adhesion with interfacial gap of 2.9-$26.8{\mu}m$ was observed partially.

• Journal of Astronomy and Space Sciences
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• 제32권4호
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• pp.427-434
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• 2015

Coronal Mass Ejections (CME), which originate from active regions of the Sun's surface, e.g., sunspots, result in geomagnetic storms on Earth. The variation of the Earth's geomagnetic field during such storms induces surface currents that could cause breakdowns in electricity power grids. Hence, it is essential to both monitor Geomagnetically Induced Currents (GICs) in real time and analyze previous GIC data. In 2012, in order to monitor the variation of GICs, the Korean Space Weather Center (KSWC) installed an induced current measurement system at SINGAPYEONG Substation, which is equipped with 765 kV extra-high-voltage transformers. Furthermore, in 2014, two induced current measurement systems were installed on the 345 kV high-voltage transformers at the MIGEUM and SINPOCHEON substations. This paper reports the installation process of the induced current measurement systems at these three substations. Furthermore, it presents the results of both an analysis performed using GIC data measured at the SINGAPYEONG Substation during periods of geomagnetic storms from July 2013 through April 2015 and the comparison between the obtained GIC data and magnetic field variation (dH/dt) data measured at the Icheon geomagnetic observatory.

• 대한전자공학회논문지
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• 제11권3호
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• pp.36-41
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• 1974

임의의 차수의 전진함수의 실현에 전류변환 GIC를 쓰는데 고 admittance변환함수 h(s)가 k/s 되게 하는 경우와 k/s가 되게 하늘 경우와 두가지에 대해서 실현방법을 제시하였다. h(s)=k/s의 방법이 수동회로망에 Capacitor를 표구하지 않은 이점이 있으나 필요한 GIC의 개수가 h(s)=k/s의 경우보다 많아진다. 제시된 두가지 방법으로 2차의 부원함수를 실현하였고 회로소자의 Q와 발진주파수에 대한 Sensitivity를 조사하여 h(s)=k/s 의 방식이 비교적으로 유리함을 밝혔다.