• 한국전기전자재료학회논문지
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• 제24권7호
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• pp.589-593
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• 2011

[ $SnO_2$ ]nano powders were prepared by solution reduction method using tin chloride($SnCl_2{\cdot}2H_2O$), hydrazine($N_2H_4$) and NaOH. The $SnO_2$ thick films for gas sensors were fabricated by screen printing method on alumina substrates and annealed at $300^{\circ}C$ in air, respectively. XRD patterns of the $SnO_2$ nano powders showed the tetragonal structure with (110) dominant orientation. The particle size of $SnO_2$ nano powders at the ratio of $SnCl_2:N_2H_4$+NaOH= 1:6 was about 60 nm. The sensing characteristics were investigated by measuring the electrical resistance of each sensor in a test box. Sensitivity of $SnO_2$ gas sensor to 5 ppm $CH_4$gas and 5 ppm $CH_3CH_2CH_3$ gas was investigated for various $SnCl_2:N_2H_4$+NaOH proportion. The highest sensitivity to $CH_4$ gas and $CH_3CH_2CH_3$ gas of $SnO_2$ sensors was observed at the $SnCl_2:N_2H_4$+NaOH= 1:8 and $SnCl_2:N_2H_4$+NaOH= 1:6, respectively. Response and recovery times of $SnO_2$ gas sensors prepared by $SnCl_2:N_2H_4$+NaOH= 1:6 was about 40 s and 30 s, respectively.

• 한국작물학회지
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• 제49권5호
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• pp.368-372
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• 2004

The lignin contents between IR-29 and Pokkali were not significantly different in the absence of NaCl, but they were slightly increased at 40 mM NaCl. Although lignin contents were not relatively significantly different between salt treated and control plants, the total yields of alkaline nitrobenzene oxidation ranged from 17.4-20.0 mg/g of cell wall residue at 40 mM NaCl were significantly different compared with control plants (11.8-12.2 mg/g). The total amounts of ester-linked hydroxycin-namic acids in IR-29 were decreased from 14.5 to 9.9mg/g, while Pokkali is almost same levels (14.9-15.0 mg/g) under treated and control with 40 mM NaCl. In contrast, the total amounts of ether-linked hydroxycinnamic acids were increased from 9.4 to 13.9 mg/g together with an opposite trend in Pokkali as a decrease 10.9 to 8.8 mg/g under treated and control with 40 mM NaCl. These results revealed that IR-29 is more sensitive in response to 40 mM NaCl in terms of hydroxycinnamic acids than Pokkali.

• 한국발생생물학회지:발생과생식
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• 제26권2호
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• pp.71-77
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• 2022

In response to luteinizing hormone (LH), a higher concentration of progesterone (P4) is produced in luteal cells of corpus luteum (CL). Mitochondria are an essential cellular organelle in steroidogenesis. The specific engagement of the concept regarding mitochondrial shaping with early stages of steroidogenesis was suggested in reproductive endocrine cells. Although the specific involvement of GTPase dynamin-related protein 1 (Drp1) with steroidogenesis has been demonstrated in luteal cells of bovine CL in vitro, its actual relationship with ovarian steroidogenesis during the estrous cycle remains unknown. In this study, while Fis1 and Opa1 protein levels did not show significant changes during the estrous cycle, Drp1, Mfn1, and Mfn2 proteins exhibited relatively lower levels at proestrus than at estrus or diestrus. 3β-HSD showed higher levels at proestrus than at estrus or diestrus. In addition, Drp1 phosphorylation (s637) was higher in proestrus than in estrus or diestrus. Immune-positive cells for Drp1, pDrp1 (s637), and 3β-HSD were all localized in the cytoplasm of luteal cells in the CL. The immune-positive cells for 3β-HSD were more frequently seen in the CL at proestrus than at estrus or diestrus. Immunoreactivity for Drp1 in luteal cells at proestrus was weaker than that at estrus or diestrus. However, pDrp1 (s637) immune-positive cells were mostly detected in luteal cells at proestrus. These results imply that steroidogenesis (P4 production) in the CL is closely related to phosphorylation of Drp1 at serine 637. Taken together, this study presents evidence that Drp1 phosphorylation at serine 637 is an important step in steroidogenesis in the CL.

• 생명과학회지
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• 제18권8호
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• pp.1164-1168
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• 2008

염분 스트레스에 노출된 옥수수(Zea mays) 유식물의 원뿌리는 길이생장이 억제되는데, 본 연구에서는 위와 같은 조건에서 뿌리의 굴중성 반응을 조사하였다. 고농도의 NaCl과 KCl에 의해 스트레스를 받은 옥수수 원뿌리는 수평 상태에서 중력 자극을 받기 시작한 지 2시간 이후부터 대조구에 비하여 현저한 굴중성 반응을 나타내었다. 이러한 굴중성 촉진 현상은 $Na^{+}$가 아니라 $K^{+}$에 의한 것이었으며, Cl-도 굴중성 반응 촉진에 기여하였다. 이로부터 이들 $K^{+}$와 $Cl^{-}$이온들이 세포 팽창에 필요한 삼투 조절자로 기능한다는 결론을 얻었다. 또한 염분 스트레스에 의하여 뿌리의 길이 생장이 억제되더라도 중력장 내에서의 위치 결정은 억제되지 않고 오히려 촉진된다는 점도 확인하였다.

• 한국환경농학회지
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• 제18권1호
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• pp.61-65
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• 1999

본 실험은 간척지 식물들의 내염성 정도를 알아보고 식물의 내염성 기작을 규명하고자 14종의 식물을 공시하여 이들의 생리적 변화를 확인하였다. 염 농도가 높아질수록 식물체내의 프롤린 함량은 증가하였다. 깨풀, 도깨비바늘, 붉은서나물, 망초, 미국개기장, 까마중은 200mM NaCl에서 급격한 함량 증가를 보였으나 가는갯는쟁이, 나문제는 변화의 폭이 작았다. 또한 염 농도가 높아질수록 식물내 $Na^+$, $Cl^-$의 함량은 모두 증가하였다. 비염생식물인 깨풀, 바랭이, 까마중은 200mM NaCl에서 $Na^+$과 $Cl^-$은 증가폭이 컸고 나문제, 가는갯는쟁이, 갯개미자리는 200mM까지 $Na^+$, $Cl^-$은 증가폭이 작았다. 염 농도가 높아질수록 $K^+/Na^+$율은 감소하였고, 염생식물인 나문제, 가는갯는쟁이, 갯개미자리의 $K^+/Na^+$ 율은 감소폭이 작아 세포내 이온균형의 항상성이 유지되고 있음을 보여주었다.

• 전기화학회지
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• 제19권2호
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• pp.29-38
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• 2016

전기화학적 방법을 통한 요산 (Uric acid) 정량분석을 위해 수용성 고분자 (hydrogel polymer)를 배위시킨 오스뮴 고분자 화합물과 요산 산화효소 (Uricase), 가교를 위한 PEGDGE (poly(ethylene glycol) diglycidyl ether)가 혼합된 용액을 스크린 프린팅된 탄소 전극 (SPCEs) 위에 흡착하여 측정하였다. 수용성 오스뮴 고분자의 전위를 조절하기 위해 리간드인 피리딘링의 4번 위치에 다른 전기음성도의 작용기를 갖는 오스뮴 고분자 화합물을 합성하였다. 합성된 오스뮴 고분자 화합물은 PAA-PVI (Poly(acrylic acid)-poly(vinyl imidazole)-$[osmium(4,4^{\prime}-dichloro-2,2^{\prime}-bipyridine)_2Cl]^{+/2+}$), PAA-PVI-$[osmium(4,4^{\prime}-dimethyl-2,2^{\prime}-bipyridine)_2Cl]^{+/2+}$, PAA-PVI-$[osmium(4,4^{\prime}-dimethoxy-2,2^{\prime}-bipyridine)_2Cl]^{+/2+}$이다. 제작된 효소전극은 순환전압전류법 (cyclic voltammetry)을 통해 uric acid에 의한 오스뮴 고분자 화합물들의 산화 촉매 전류(oxidation catalytic current)를 측정하여 uric acid의 농도를 정량적으로 분석할 수 있었다. 오스뮴 고분자 화합물들 중 0.215 V의 산화환원 전위를 갖는 $PAA-PVI-[Os(dme-bpy)_2Cl]^{+/2+}$ (PAA-PVI-osmium$(4,4^{\prime}-dimethyl-2,2^{\prime}-bipyridine)_2Cl$]$^{+/2+}$) 화합물을 이용하여 대표적인 간섭물질인 아스코르브산 (AA)과 포도당 (glucose)의 산화 신호의 간섭효과를 피할 수 있었다. 이를 이용하여 제작된 전극은 0.33 V 전위에서 다양한 농도의 uric acid (1.0, 1.5, 2.0, and 5.0 mM)의 전류를 측정한 결과 $r^2=0.9986$의 좋은 선형성을 갖는 것을 확인하였다. 이는 복잡하지 않은 간단한 방법과 일회용의 전극을 사용하기 때문에 현장현시 검사 (point of care; POC)에 적합한 요산측정용 바이오센서로서의 가능성을 확인 할 수 있었다.

• 한국축산식품학회지
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• 제30권5호
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• pp.764-772
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• 2010

Staphylococcus aureus lipase is regarded as a virulence factor. The response of lipase activity to various factors can provide important insights concerning the prevention of S. aureus during meat fermentation. This study was conducted to evaluate the main effects of nutrients used in culture media, and their combined effects on the inhibition of lipase activity and cell growth of pathogenic S. aureus SK1593 isolated from fermented pork meat. A Plackett-Burman design was used to evaluate the main effects of variables, including olive oil, soybean oil, grapeseed oil, sesame oil, $CuSO_4$, $MgCl_2$, $KNO_3$, $CaCl_2$, and KCl. Significant negative effects on lipase activity were detected with soybean oil, grapeseed oil, $KNO_3$, and $CaCl_2$. Additionally, these nutrients were further selected as variables for the investigation of their combined effect on lipase activity, via response surface methodology. In order to confirm the regression model, a situation that only inhibits lipase activity was simulated. The predicted lipase activity and cell growth of the simulated situation were 14.0 U/mL and $9.6\;{\log}_{10}$ (CFU/mL), respectively, and the estimated value of those in the same medium showed 15.14 U/mL and $9.4\;{\log}_{10}$(CFU/mL) respectively. The lipase activity of the simulated medium was inhibited approximately 5-fold as compared to the basal medium, but no significant differences in cell counts were noted to exist between the basal and simulated media. These results suggest that soybean oil, grapeseed oil, $KNO_3$, and $CaCl_2$ can be used to inhibit the growth of pathogenic S. aureus during the process of meat fermentation.

• 대한화학회지
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• 제28권2호
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• pp.86-94
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• 1984

${\beta}-Ag_3SI$의 단결정을 만들어 막전극으로의 응용을 살펴보았다. 그 결과 할로겐 이온들에 대해 감응함을 알았고, 분리용액법과 혼합용액법으로 할로겐 이온들에 대한 선택계수를 얻어 이론값과 비교검토 하였으며, 전위시간 곡선으로 부터 이 전극이 유리 전극기구에 의해 전도함을 알았고, 넓은 pH 범위에서 전위가 일정한 값을 가짐을 알았다. 한편 분석화학에의 응용을 살펴 본 결과 할로겐이온의 혼합용액에서 좋은 지시전극으로 사용할 수 있음을 알았다

• The Korean Journal of Physiology and Pharmacology
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• 제8권5호
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• pp.289-293
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• 2004

To investigate whether VacA (vacuolating toxin) produced by Helicobacter pylori Korean stain 99 induces intestinal secretion, purified VacA was added to T84 cell monolayers mounted in Ussing chambers, and electrical parameters were monitored. Mucosal addition of low pH-pretreated VacA increased short circuit current (Isc). The effect was time- and dose-dependent and saturable. The time-to-peak Isc was concentration-dependent. Chloride channel inhibitors, niflumic acid or 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB), inhibited VacA-stimulated Isc. Carbachol (CCh)-induced increase of Isc was prolonged by the addition of VacA to the mucosal side only. The effect was unaltered by the addition of niflumic acid. VacA did not show cytopathic effects. These studies indicate that VacA is a nonlethal toxin that acts in a polar manner on T84 monolayers to potentiate $Cl^-$ secretion and the response to CCh secretion without decrease in monolayer resistance. VacA may contribute to diarrhea diseases in human intestinal epithelial cells.

• 분석과학
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• 제13권3호
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• pp.315-322
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• 2000

시금치의 뿌리 조직과 ferrocene을 탄소반죽 전극에 고정하여 과산화수소를 정량할 수 있는 전극을 만들었다. Ag/AgCl 전극에 대하여 -0.3~0.0V의 전위의 범위에서 전극의 감도를 관찰하였으며 전극의 감응시간은 11.8sec로 나타났다. 전극의 검출한계는 $2.25{\times}10^{-6}M$ 이었으며, $1.0{\times}10^{-3}M$ 과산화수소를 이용해 15회 반복 측정한 결과, 상대표준편차는 1.87% 이었다. 효소전극의 감도는 19일 사용 후 40%로 감소하였다.