• Korean Journal of Environment and Ecology
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• v.8 no.2
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• pp.177-182
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• 1995

Amphibian and Reptilian fauna in Chuwangsan National Park was carried out both Apr. 28, 1994 - Apr. 30, 1994 and Aug. 4, 1994-Aug. 5, 1994. 7 species in 5 Families in Amphibia and 7 species in 3 Families in Reptilia were observed in this survey. Rana dyhowskii in Amphibia and Rhabdophis tigrinus tigrinus in Reptilia were revealed dominant species in Chuwangsan National Park. The results in this survey would be use to baseline data significantly after the project of construction works in Chuwangsan National Park.

• Journal of Communications and Networks
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• v.15 no.5
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• pp.443-456
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• 2013

Compressive sensing (CS) is a novel sampling paradigm that samples signals in a much more efficient way than the established Nyquist sampling theorem. CS has recently gained a lot of attention due to its exploitation of signal sparsity. Sparsity, an inherent characteristic of many natural signals, enables the signal to be stored in few samples and subsequently be recovered accurately, courtesy of CS. This article gives a brief background on the origins of this idea, reviews the basic mathematical foundation of the theory and then goes on to highlight different areas of its application with a major emphasis on communications and network domain. Finally, the survey concludes by identifying new areas of research where CS could be beneficial.

• Journal of Photoscience
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• v.3 no.3
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• pp.133-136
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• 1996

Calcium modulates the activity of guanylate cyclase and plays a key role in dark and light adaptation in the visual system. We have measured the Ca$^{2+}$, K$^+$ and Na$^+$ concentration in dark and light adapted bullfrog's (Rana catesbeiana) vitreous humor by using the atomic absorption spectrophotometer. The calcium concentration of the light adapted bullfrog's vitreous humor was higher than that of the dark adapted bullfrog's vitreous humor. This means that ion activity between the photoreceptor and vitreous humor side is light dependent and we have found that a Ca$^{2+}$ channel and Na$^+$ - Ca$^{2+}$ exchanger exist in the vitreous humor.

• Korean Journal of Environment and Ecology
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• v.15 no.2
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• pp.153-158
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• 2001

영산강 수계의 습지생태계 모니터링의 일환으로 4개 지역을 선정하여 황소개구리 205개체를 채집하여 이들의 외부기형 출현율 및 양상을 조사하고 그들의 체내 조직에 축적된 중금속 농도를 분석하였다. 황소개구리의 기형 출현율은 6.8%로 다른 척추동물에서의 자연발생률 3%보다 높았으며, 기형은 모두 앞 또는 뒷발갉에서 나타났다. 유형별로 보면 결손(Ectrodactyly)이 64.3%로 가장 많았고 다음으로 확장(Dilation)이 28.6%, 절단(Truncation) 7.1%의 순이었다. 정상과 기형 개체간에 중금속의 농도를 조직별로 비교해 본 결과 기형개체의 신장에서 Mn은 4배, Zn 은 1.5배, Cu은 7배, Pb는 8배, Cd는 7배 정도 높았다. 또한 기형 개체에서는 이들 원소의 조직분포 패턴도 변화한 것으로 나타났다. 이러한 결과들로부터 황소개구리는 습지생태계의 모니터링 시료로서 유용하게 이용될 수 있음을 알 수 있었다.

• Applied Microscopy
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• v.25 no.4
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• pp.115-123
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• 1995

This study was carried out to observe the functional ultrastructures of photoreceptor cells in frog(Rana catesbeiana) retina using transmission electron microscope. The photoreceptor cells are divided into two types-rod and cone cells-consist of outer and inner segment. The long outer segment of rod cell contains dense stacks of membrane and formed vertical and horizontal folds. The outer segment of cone cell is small, and vertical and horizontal folds are not exist. The electron dense cytoplasm of rod cell contains compact mitochondria, Golgi complexes, and endoplasmic reticula. The inner segment of cone cell shows low electron density and contains a large lipid droplet in the upper part of inner segment. In addition, cone cell contains many mitochondria, Golgi complexes. rough endoplasmic reticula, ribosomes and numerous glycogen particles. It is believed that these ultrastructural characteristics are closely associated with photoreceptive function of photoreceptor cells in frog retina.

• Natural Product Sciences
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• v.12 no.4
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• pp.241-246
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• 2006

Alstonia scholaris is known as 'Saptaparna' in Ayurvedic System of Medicines and the bark is used for the treatment of various diseases. It has various ethnomedicinal values as different traditional communities find diverse medicinal properties. The present communication deals with the seasonal variation studies of the stem bark of this plant. The bark was collected in the month of January, July and November. There is no macro-microscopical changes in all the three seasons but the ash values showed significant differences. Crude fibre content showed sharp decline from January to July to November. Total tannin percentage was found maximum in January and minimum in June. TLC finger print profile showed more concentration of constituents in January as compared to June and November. Hence, the bark may show more efficacy when collected in January.

• Macromolecular Research
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• v.14 no.1
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• pp.34-37
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• 2006

Attaching the organosilyl groups to macromolecular chains of 2-hydroxyethyl methacrylate (HEMA) should lead to important modifications of polymer properties. t-$BuMe_{2}Si$ and cubane-l, 4-dicarboxylic acid (CDA) were covalently linked with 2-hydroxyethyl methacrylate (HEMA). The silyl-linked HEMA is abbreviated as TSMA, while cubane-l ,4-dicarboxylic acid (CDA) linked to two HEMA groups is the cross-linking agent (CA). Free radical cross-linking copolymerization of TSMA and HEMA with various ratios of CA as the cross-linking agent was carried out at 60-70$^{circ}C$. The compositions of the cross-linked, three-dimensional polymers were determined by FTIR spectroscopy. The glass transition temperature ($T_{g}$) of the network polymers was determined calorimetrically. The $T_{g}$ of the network polymer increased with increasing cross-linking degree.

• The Korean Journal of Zoology
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• v.37 no.2
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• pp.174-181
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• 1994

3 종의 한국산개구리를 사용하여 여포들이 생성하는 스테로이드와 난자의 성숙능이 번식기 근처에서 어떻게 변하는가를 조사하였다. 개구리의 여포를 생체외 배양하면서 이들이 뇌하수체추출물(frog pituitary homogenate, FPH) 혹은 CAMP의 자극으로 생성하는 progesterone(Pa)과 testosterone(T)의 양을 측정하여 이로부터 P4yT의 비율을 구하였으며 여포난자들이 FPH. P4 혹은 12-0-tetrsdecanoyl phorbol-13-acetate(TPA)에 반응하여 성숙을 일으키는 시기를 조사하였다. 북방산개구리의 여포난자는 11월 부터 호르몬에 반응하여 성숙을 일으켰으며 2월에 PJT의 비율이 급격히 증가하였다 참개구리는 5월에 가서of PJT의 비율이 현저히 증가하고 FPH에 반응하여 성숙을 일으켰다. 그러나 P4에 의한 난자성숙은 3월부터 시작하였다 옴개구리는 7월에 P4/T 비율의 증가가 있었으며 이때부터 또한 TPA에 반응하여 난자의 성숙을 일으켰다 따라서 3종의 개구리에서 모두 각각의 번식기 근처에서 PJT의 비가 급격히 증가하고 또한 성숙능이 생긴다는 것을 알 수있었다.

• The Korean Journal of Zoology
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• v.24 no.1
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• pp.38-57
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• 1981

Cardell, Jr. (1964)는 도룡뇽의 뇌하수체 전염에서 5가지의 분비세포를 구분하였으며 Dent와 Gupta (1967), 그리고 Iturrza (1964)는 영원류에서 5가지 분비세포를 구분하여 보고한 바 있다. 또 Doerr-Schott (1965)는 개구리에서 5가지 분비세포를, Mira-Moser (1969, 1970)는 6가지의 분비세포와 한가지의 무과립세포를 구분하였다. Shinkawa등 (1972)도 역시 7가지 cell type을 구분하였다. Shinkawa와 Nakai (1972)는 참개구리에서 역시 7가지 cell type을, 그리고 이들이 선정한 3 cell type에서 ACTH를 분비한다는 사실을 보고 하였다. 이에 본 연구자들은 산개구리를 재료로 하여 우선 동면기의 것을 실험하였던 바 7가지 cell type을 구분한 바 있고, 다시 활동기의 것을 재료로하여 세포내 소기관의 변화를 관찰하였는데 여기서 몇가지 차이점을 보고하는 바이다.

• The Journal of Korean Physical Therapy
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• v.7 no.1
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• pp.1-8
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• 1995

The purpose of this study was to determine the effects of high voltage pulsed current(HVPC) and low voltage pulsed current(LVPC) on posttraumatic edema formation in frog hind limbs In this study, 16 bullfrogs(Rana Catesbeiana), weighting 189g to 340g were used. Limb 16 anesthetized bullfrogs were systemically injuried by weight drop. One hind limb of each frogs was randomly selected to receive continuous 120 pps HVPC and 100 pps LVPC at $90\%$ of motor threshold(HVPC : 33.3v, LVPC : 0.2-1mA). The opposite hind was remained as a control. A series of six 30-minute treatment(interrupted by 30-minute rest) was begun minutes after injury. The results were as follows. 1. Cathodal HVPC has heed shown to be effective in curbing posttraumatic edema formation in frogs, but anodal HVPC did not effect. 2. Volumes of hind limbs treated with LVPC were not significantly different over time from those of untreated hind limbs. 3. Therefore, waveform(HVPC versus LVPC) seems to influence the efficacy of electrotherapy for edema control. 4. Electrical stimulation were not increased edema formation on frog hind limbs.