• The Korean Journal of Physiology
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• 제13권1_2호
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• pp.41-50
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• 1979

The activation mechanism of K-induced contracture was studied in renal vascular muscle which does not generate an action potential readily and in taenia coli which generates a spike potential spontaneously. Helical strips of arterial muscle from rabbit renal arteries and longitudinal strips of taenia coli from guinea-pig's colons, respectively, were prepared. All experiments were performed in Tris-buffered Tyrode solution which was aerated with 100% $O_2$ and kept $35^{\circ}C$. Renal arterial muscles developed the contracture rapidly, which was composed of a small phasic and a large tonic components, when exposed to a 40 mM K-Tyrode solution. In the absence of external $Ca^{++}$, however, no K-contracture appeared. The contracture induced by K-depolarization was abolished by the treatment with verapamil, which is known to be a selective $Ca^{++}-blocker$ through potential-sensitive $Ca^{++}-channel$. K-contracture of taenia coli showed the contracture composed of a large phasic and a small tonic components. In the $Ca^{++}-free$ Tyrode solution, only the tonic component was abolished and almost no change in the phasic component was observed. The amplitude of tonic component was dependent on the external $Ca^{++}$; The tonic component increased dose-dependently by a stepwise increase of the external $Ca^{++}$, and this component decreased in parallel with the increase of verapamil in the external medium. The results of this experiment suggest that K-contracture of rabbit renal artery is the direct result of the influx of the external $Ca^{++}$, while that of taenia coli is the result of both $Ca^{++}$ influx and the release of sequestered $Ca^{++}$.

• 천문학논총
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• 제32권1호
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• pp.59-61
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• 2017

The AKARI 9 and 18 µm diffuse maps reveal the all-sky distribution of the interstellar medium with relatively high spatial resolution of ~6". The zodiacal light is a dominant foreground component in the mid-infrared. Thus, removal of the zodiacal light is a critical issue to study low surface brightness Galactic diffuse emission. We carried out modeling of the zodiacal light based on the Kelsall model which is constructed from the COBE data. In the previous study, only a time-varying component of the zodiacal light brightness was used for determination of the model parameters. However, there remains a residual component of the zodiacal light around the ecliptic plane even after removal with the model. Therefore, instead of using a time-varying component, we use the absolute brightness of the zodiacal light and we find that the new model can better remove the residual component. As a result, the best-fit model parameters are changed from those in the previous study. We discuss the properties of the zodiacal light based on our new result.

• 폴리머
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• 제31권5호
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• pp.374-378
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• 2007

Acrylamide(AM), diacetone acrylamide(DAAM) 및 acrylic acid(AAc)를 사용하여 수용성 삼원공중합체를 제조하고, 4-azidoaniline을 반응하여 azido기를 고분자 곁사슬에 도입한 일성분계 포토레지스트를 제조하였다. AM을 주성분으로 하고 DAAM을 공단량체로 사용한 공중합체를 합성하구 광가교제로 4,4'-diazidostilbene 2,2'-disulfuric acid sodium salt(DAS)를 혼합한 이성분계 포토레지스트를 제조하여 두 종류 포토레지스트의 감광특성을 비교하였다. 포토레지스트의 azido기 1 mol에 대한 감광특성은 고분자 곁사슬에 azido기를 가진 일성분계의 경우가 bis-azido기를 가진 이성분계보다 약 4배정도 우수한 감광성을 나타내었다. 직경 $110{\mu}m$ 크기의 원형패턴을 낮은 광세기에서 일성분계 포토레지스트를 사용하여 얻었으며, 노광부와 비노광부 계면에 잔존물이 없이 원형 패턴이 형성되어 블랙 매트릭스용 negative 포토레지스트로 활용이 기대된다.

• KSBB Journal
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• 제29권3호
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• pp.165-178
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• 2014

Statistical medium optimization has been carried out for the production of succinic acid in anaerobic fermentations of Actinobacillus succinogenes. Succinic acid utilized as a precursor of many industrially important chemicals is a fourcarbon dicarboxylic acid, biosynthesized as one of the fermentation products of anaerobic metabolism by A. succinogenes. Through OFAT (one factor at a time) experiments, corn steep liquor (CSL), a very cheap agricultural byproduct, was found to have significant effects on enhanced production of succinic acid, when supplemented along with yeast extract. Hence, using these factors including glucose as a carbon/energy source, interactive effects were investigated through $2^n$ full factorial design (FFD) experiments, showing that the concentration of each component (i.e., glucose, yeast extract and CSL) should be higher. Further statistical experiments were conducted along the steepest ascent path, followed by response surface method (RSM) in order to find out optimal concentrations of each constituent. Consequently, optimized concentrations of glucose, yeast extract and CSL were observed to be 180 g/L, 15.08 g/L and 20.75 g/L respectively (10 g/L of $NaHCO_3$ and 100 g/L of $MgCO_3$ to be supplemented as bicarbonate suppliers), with the estimated production level of succinic acid to be 92.9 g/L (about 3.5 fold higher productivity as compared to the initial medium). Notably, the RSM-estimated production level was almost similar to the amount of succinic acid (92.9 g/L vs. 89.1 g/L) produced through the actual fermentation process performed using the statistically optimized production medium.

• 미생물학회지
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• 제6권4호
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• pp.113-121
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• 1968

This study has been aimed to determine the ecological factors with relationship to the Jongkok production in view of fermentation technology by means of some strains, Asp. kawachii, which is now preserved by the author and the following factors are included during the study; inorganic salts, nitrogen, sugar, water contents and temperature. The results, are as follows: (a) Sugar among other above-mentioned factors is increasingly affecting the number of the short type of conidiophore on culture medium and the conidiophore is increased by direct ratio until glucose concentration of 50%, at which concentration is mostly effective for the short type of conidiophore, while other factors did not affect on it. (b) Until glucose concentration of 50% sugar component of culture medium is favorable for the spore formation of Asp. kawachii by direct ratio. And peptone or asparagine on nitrogen medium, calcium-phosphate among other inorganic salts, wheat bran and rice branare also favorable, but other factors rientioned earlier show no relationship with the spore formation. Sugar, however, also related with the spore color clearness of crimson and light brown, and spore color is mostly clear at the point of glucose concentration until 50%. And asparagine on nitrogen medium, calcium phosphate among other inorganic salts, rice bran did all affect on the color clearness, while other factors did not concern with color clearness. (c) Water, sugar and temperature have related with the acid formation which is promoted, by direct ratio at the point of water-saturated condition and glucose concentration of 50%, while temperature at $25^{\circ}C$favorably affected on the acid formation which is increased by inverse ratio at the temperature$25^{\circ}C$ to $45^{\circ}C$ And pH did not relate with the acid formation. (d) Cylindrical plate method devised by the author is mostly favorable for the preservation and isolation of culture, compared with the traditional slant medium method.

• 대한의생명과학회지
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• 제19권1호
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• pp.41-47
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• 2013

Pluripotent stem cells (PSCs) have lots of potential in biomedical sciences owing to its potential to differentiate into any kind of cells in the body. However, it is still a challenge to culture PSCs on a large scale for application to regenerative medicine. Herein, we introduce a synthetic polymer that enables large-scale suspension culture of human PSCs. By employing suspension culture, it became unnecessary to use conventional substrata such as mouse embryonic fibroblast (MEF) or Matrigel$^{TM}$, which are believed to be main causative sources of xenogeneic contamination in cultured human PSCs in vitro. Human PSCs were cultured in the medium in which elastin-like polypeptide (ELP) dissolved. The ELP in the medium became harden as temperature increases by transforming the medium into a semi-solid gel that supported growth of human PSCs in suspension. Gel-sol transition temperature of ELP can be adjusted by modifying the peptide sequence in which 5 amino acids, Val-Pro-Gly-Xaa-Gly, repeated sequentially. We constructed 3D suspension media having transition temperature around $33{\sim}35^{\circ}C$ using an ELP consisted of 40, 60, or 80 repeats of a monomer, which was Val-Pro-Gly-Val-Gly. Among the ELPs, ELP80 was chosen as the best ELP to support growth of human PSCs in suspension culture. This result suggests that the ELP80 can be a medium component for culturing human PSCs in large-scale.

• KSBB Journal
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• 제7권2호
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• pp.92-95
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• 1992

동물세포 대량 배양의 저혈청 배지를 개발하기 위하여 융합제작한 하이브리도마 KA112를 대상으로 혈청의 역할을 살펴본 다음, 혈청의 구성인자를 최고세포 농도를 결정하는 소모성 영양인자와 세포성장속도를 결정하는 성장 제어인자로 나눈 혈청 역할모델을 개발하여 실험 결과와 비교 검토하였다. 이 모델이 의하면 7%이상의 혈청 첨가시에는 혈청내의 소모성 인자가 그와 같은 역할을 맡게 되며, 3% 첨가시에는 성장 제어 인자의 고갈로 인해 세포성장속도가 제한을 받는다. 동시에 소모성 단일 인자가 혈청농도에 의하여 limiting하게 됨에 따라 최고 도달 세포 농도와 세포 성장 속도를 제어함을 설명할 수도 있다. 이러한 실험결과들은 혈청농도와 기저배지 성분들의 농도를 항상 균형있게 고려해 주어야 함을 보여주고 있다.

• 한국지진공학회논문집
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• 제9권4호
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• pp.67-74
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• 2005

이 논문에서는 포화된 2상 지반의 동적해석에서 원역을 모형화하기 위한 새로운 무한요소를 제안하였다. 무한요소법은 무한영역 또는 반무한영역을 모형화해야 하는 공학문제에 효과적으로 적용되어 왔다. 그러나 현재까지 개발된 2상지반의 동적해석을 위한 무한요소는 형상함수에 사용될 수 있는 파동성문이 2개(Pl파와 P2파)로 한정되어 있다. 이 논문에서는 이와 같은 제한을 없애고 임의 개수의 파동성분을 고려할 수 있도록 하는 정식화 과정을 제안하였다. 구조물을 포함하는 근역은 유한요소로 나타내며 원역은 평행층상 반무한 지반으로 가정하였다. 제안된 무한요소의 타당성은 1차원 및 2차원 파동전달문제를 해석하고 이를 이론해 및 정밀수지해석 해와 비교하여 검증하였다.

• 한국버섯학회지
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• 제22권2호
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• pp.67-72
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• 2024

본 연구에서는 느타리버섯의 생육단계별 미생물 군집을 species수준에서 조사하였다. 살균전 배지에서는 그람 양성균이 우점하였다. 반면 배양완료 배지, 수확 후 배지, 그리고 자실체에서는 그람 음성균이 우점하였다. 미생물의 다양성을 확인한 결과 살균 전 배지가 다른 생육단계에 비해 다양한 미생물을 포함하고 있는 것을 확인하였으며, 배양완료배지, 자실체, 수확 후 배지의 순서로 다양성이 감소하는 경향을 보였다. 미생물의 유사도분석을 한 결과 배양완료배지와 수확 후 배지가 유사한 미생물군집을 보이는 것을 확인하였고, 자실체의 경우 일부 유사성을 보이지만 전반적으로는 차이를 나타내었다. 이러한 결과를 토대로 확인하였을 때 살균과정을 거치지 않은 살균 전 배지에서는 검출되지 않은 Pseudomonas tolaasii가 살균 과정을 거친 배양완료배지, 수확후 배지에서 검출된 것으로 보아 살균 이후 접종 혹은 배양하는 과정에서 미생물이 유입하였을 것으로 추정된다. 또한 유해균이 유입되었지만 병징이 나타나지 않은 것은 유해균을 억제하는 유익균의 존재와 병징을 일으키는 농도보다 낮은 것의 영향으로 추정된다. 앞으로, 유해균이 유입되었지만 병징이 나타나지 않은 원인과 기작에 대한 연구가 필요하다.

• Bulletin of the Korean Chemical Society
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• 제34권8호
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• pp.2431-2435
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• 2013

A simple and efficient method for the synthesis of spiro[4H-pyran-oxindole] derivatives by means of three-component reactions between isatins, malononitrile or ethyl cyano-acetate, and 1,3-dicarbonyl compounds in the presence of catalytic amount of magnesium perchlorate in 50% aqueous ethanol medium has been described.