• 대한환경공학회지
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• 제22권11호
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• pp.1969-1976
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• 2000

폐수의 복합독성과 다수의 미지 화합물의 영향을 평가하는 것은 많은 시간이 요구되고 분석상 어려움이 존재하는 경우가 많다. 그러므로 폐수중 독성을 나타내는 원인물질의 탐색과 처리효과를 평가하기 위한 방법을 확립하는 것이 절실히 요구된다. 본 연구에서는 질산화 저해제를 이용하여 혼합미생물중 질산화 미생물과 종속영양미생물을 구분하여 암모니아 저해도 실험을 수행하였으며, 이때 저해도는 dehydrogenase activity(DHA)를 이용한 미생물활성도의 차이로서 평가하였다. DHA에 의한 암모니아 저해 연구는 총 암모니아의 영향, 유리 암모니아의 영향, 질산화 미생물과 종속영양미생물의 암모니아 저해도에 대해 각각 평가되었다. 암모니아 독성은 총 암모니아 농도와 pH가 증가할수록 크게 나타나 유리 암모니아의 역할이 중요하게 작용함이 밝혀졌으나 미생물의 DHA는 총 암모니아와 유리 암모니아가 함께 고려되어야 정확히 평가될 수 있었다. 3.000mg/L 이상의 고농도의 암모니아에서는 질산화 미생물이 종속영양미생물 보다 심한 저해를 받는 것으로 나타났다.

• 한국식품위생안전성학회지
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• 제14권3호
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• pp.270-276
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• 1999

Alteromonas sp. SR-14의 배양여액을 사용하여 C. calcitrans의 증식에 미치는 영향과 조류 증식저해 물질의 특성을 살펴보았다. Alteromonas sp. SR-14의 peptone broth 배양여액은 C. calcitrans에 대하여 증식 저해 활성을 나타내었으며, 이 균에 의한 조류 증식 저해 물질은 온도 $15~20^{\circ}C$, pH 7.0~9.0, 염분 농도 $23~30{\textperthousand}$의배양 조건에서 강한 활성으로 생성되었으며, 이러한 조건(온도 $20^{\circ}C$, pH 8.0, 염분 농도 $30\textperthousand$)에서는 정지기부터 활성이 증가하였다. Alteromonas sp. SR-14가 peptone broth에서 생산하는 조류 증식 저해 물질의 분자량은 약 3KDa~12KDa의 복합 물질이었는데, $100^{\circ}C$에서 10분간 열처리하였을 때 3~10KDa 이하의 물질은 내열성이 있었으나 10KDa 이상의 물질은 불활성 되었다.

• Journal of Chest Surgery
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• 제28권12호
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• pp.1079-1095
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• 1995

Recently endogenous digitalis-like substances were found in the blood of various cardiovascular diseases and they have been considered one of the causes of evoking hypertension. However, the mechanism of endogenous digitalis-like substances-induced hypertension is not clarified yet. Therefore, the effects of Na-K pump inhibition on the contractility of vascular smooth muscle[conduit and resistant artery were investigated, using organ bath and bioassay experiment. Aortic and carotid arterial rings[conduit artery and the branches of brachial and superior mesenteric artery[resistant artery were used to find the effect of Na-K pump inhibition. The results obtained were as followes;The magnitudes of contractions induced by norepinephrine, serotonin, or acetylcholine in all these arteries were significantly increased by the inhibition of Na-K pump. The increased contractile responses to these agonists, especially to serotonin, were much more prominant in resistant arteries. Nitroprusside-induced relaxations were attenuated by Na-K pump inhibition and there were no significant differences in the effects of Na-K pump inhibition on nitroprusside-induced relaxations of these blood vessels. Endothelium-dependent relaxation was suppressed by the inhibition of Na-K pump, especially by the administration of ouabain, and this inhibitory effect was much more prominent in the branches of superior mesenteric artery, compared with other arteries. In the branches of superior mesenteric arteries, endothelium-dependent relaxation was completely blocked by ouabain. The release of EDRF was partially suppressed by Na-K pump inhibition.From the above results, it is suggested that the hypertension due to the increase in vascular resistance can be evoked by the inhibition of Na-K pump and endogenous digitalis-like substances induce hypertension through this mechanism.

• 한국식품영양학회지
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• 제11권2호
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• pp.228-236
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• 1998

달걀의 Allergenicity를 감소시킬 수 있는 방안을 강구하고자 물리적 처리, 축합 인산염 처리 및 효소처리를 하여 Guinea pig를 이용한 Passive Cutaneous Anaphylaxis(PCA) inhibition 실험과 Non Proteic Nitrogen(NPN)정량을 통한 가수분해율의 측정결과 다음과 같은 결론을 얻었다. 달걀의 allergenicity는 가열에 의해 감소하였으며 가열시간이 길수록 단백질 가수분해율 및 PCA inhibition을 증가 시켰다. Ultraviolet 조사와 Microwave 조사는 단백 가수분해율과 PCA inhibition을 증가 시켜서 allergenicity를 저하시켰으며 ultraviolet이 저해효과가 더 컸으며 부화 달걀은 allergenicity를 감소시키지 않은 것으로 나타났다. 효소처리는 단백질의 가수분해율 및 PCA inhibition을 증가 시키며 allergenicity를 현저히 감소시켰으며 alcalase의 재해효과가 더 컸다. Polyphosphate의 참가는 단백질의 가수분해는 유도하지 않았으나 PCA inhibition을 증가 시키며 allergenicity를 감소시켰다. Allergenicity를 감소시키기 위한 처리를 한 달걀 gel의 주사전자현미경 사진은 효소처리 시 표면이 밝게 나타나서 단백질이 분해되었음을 알 수 있었고 neutrase가 alcalase보다 밝게 나타났으나 반응시간의 증가에 따라 모든 효소 표면이 밝게 나타났다. Instron에서 달걀 gel의 경도를 측정한 결과 효소와의 반응시간이 길수록 경도가 감소하는 경향을 보였다.

• BMB Reports
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• 제32권4호
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• pp.385-392
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• 1999

The $NAD^+$-specific activity of a dual coenzyme-specific isocitrate dehydrogenase (IDH; EC 1.1.1.41) from the primitive fungus Pythium ultimum was investigated to elucidate the regulatory factors that may influence the intracellular distribution of carbon and the availability of intermediates, e.g. citrate, for fatty acid synthesis. Inhibition of $NAD^+$-IDH activity by diphospho- and triphosphonucleotides (ATP, ADP, and GTP) reflected the sensitivity of this enzyme to cellular energy charge even though monophosphonucleotides (AMP and GMP) had little effect on activity. NADPH, but not NADH, substantially inhibited $NAD^+$-IDH activity, showing noncompetitive inhibition with isocitrate. Oxalacetate and ${\alpha}$-ketoglutarate showed competitive inhibition with isocitrate, while citrate and cis-aconitate showed mixed-noncompetitive inhibition with isocitrate. Inhibition by these substances ranged from 29 to 46% at 10 mM. The inhibitory effect of oxalacetate was increased synergistically by glyoxylate, which alone caused 31% uncompetitive inhibition at 10 mM, and a mixture of the two substances at 1 mM each showed 98% inhibition of $NAD^+$-IDH activity. The regulation of $NAD^+$-IDH in Pythium ultimum seems to be a complex process involving mitochondrial metabolites. The addition of glyoxylate (3 mM) and oxalacetate (3 mM) to the culture medium resulted in the production of 49% more lipid by P. ultimum.

• Journal of Dairy Science and Biotechnology
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• 제38권1호
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• pp.37-44
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• 2020

The antimicrobial activity of the ethanol extract of Hibiscus sabdariffa L. (Roselle) powder against various food-borne pathogens was tested using the lawn diffusion assay. The results showed that the ethanol extract exhibited antimicrobial activities against Staphylococcus aureus (total inhibition), Salmonella enteritidis (partial inhibition), Listeria monocytogenes (partial inhibition), Escherichia coli (partial inhibition), Cronobacter sakazakii (partial inhibition), and Bacillus cereus (partial inhibition). Therefore, it is strongly recommended that Hibiscus sabdariffa L. (Roselle) should be considered for use as a natural food-grade additive for the inhibition of various food-borne pathogens, including both gram-positive and gram-negative pathogens, and the improvement of the overall quality of various dairy products, including milk.

• 약학회지
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• 제45권1호
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• pp.85-92
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• 2001

Nitric oxide is a tonically produced vasodilator that maintains blood pressure in the normal animal. The chronic inhibition of nitric oxide synthase (NOS) elicits the hypertension in rats. However, the mechanism of hypertension induced by chronic inhibition of NOS is not clear. Thus, to clarify the mechanism of the occurance of hypertension, the changes in $\alpha$-adrenergic systems in rats treated with NOS inhibitors for 21 days were examined. Chronic administration of L-NAME significantly increased in the basal blood pressure, but chronic administration of 7-nitroindazole did not. Phenylephrine and G-protein stimulator elicited the more potent contraction in the aorta of the L-NAME-induced hypertensive rats. However when the contractile responses by phenylephrine and G-protein stimulator were calculated the proportion to the contraction by 25 mM KCL, there was no difference between the vehicle-treated rats and the L-NAME-treated rats. The density of $\alpha$-adrenergic receptors in aortic tissue was not changed by the chronic inhibition of NOS. These results suggest that hypertension induced by chronic inhibition of NOS is due to the inhibition of eNOS and the increased responses to the adrenergic drugs are due to the changes of the intracellular contactile mechanism of aortic tissue rather than the changes of receptor density.

• Journal of Electrochemical Science and Technology
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• 제10권1호
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• pp.69-81
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• 2019

The corrosion inhibiting mechanism of Vietnam orange peel essential oil (OPEO) for mild steel in 1 N HCl solution was investigated elaborately. Corrosion inhibition ability of OPEO was characterized by electrochemical polarization, electrochemical impedance spectroscopy (EIS), and weight loss method. In the corrosive solution, OPEO worked as a mixed inhibitor and the inhibition efficiency of OPEO increased with the increase of its concentration. High inhibition efficiencies over 90% were achieved for the concentration of 3 - 4 g/L OPEO, comparable to that of 3.5 g/L urotropine (URO), a commercial corrosion inhibitor for acid media used in industry. By using adsorption isotherm models (Langmuir, Temkin and Frumkin), thermodynamic parameters of adsorption were calculated. The obtained results indicated physical adsorption mechanism of OPEO on the steel surface. The components responsible for the corrosion inhibition activity of OPEO were not only D-limonene, but also other compounds, which contain C=O, C=C, O-H, C-O-C, -C=CH and C-H bonding groups in the molecules.

• Molecules and Cells
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• 제42권3호
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• pp.210-217
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• 2019

The maintenance of mitochondrial function is closely linked to the control of senescence. In our previous study, we uncovered a novel mechanism in which senescence amelioration in normal aging cells is mediated by the recovered mitochondrial function upon Ataxia telangiectasia mutated (ATM) inhibition. However, it remains elusive whether this mechanism is also applicable to senescence amelioration in accelerated aging cells. In this study, we examined the role of ATM inhibition on mitochondrial function in Hutchinson-Gilford progeria syndrome (HGPS) and Werner syndrome (WS) cells. We found that ATM inhibition induced mitochondrial functional recovery accompanied by metabolic reprogramming, which has been known to be a prerequisite for senescence alleviation in normal aging cells. Indeed, the induced mitochondrial metabolic reprogramming was coupled with senescence amelioration in accelerated aging cells. Furthermore, the therapeutic effect via ATM inhibition was observed in HGPS as evidenced by reduced progerin accumulation with concomitant decrease of abnormal nuclear morphology. Taken together, our data indicate that the mitochondrial functional recovery by ATM inhibition might represent a promising strategy to ameliorate the accelerated aging phenotypes and to treat age-related disease.

• Corrosion Science and Technology
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• 제23권1호
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• pp.20-32
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• 2024

Metal corrosion in acidic environments is a major issue in various industrial applications. This study evaluates the 4-piperonylideneaminoantipyrine (PPDAA) corrosion inhibition efficiency for mild steel in a hydrochloric acid (HCl) solution. The weight loss method was used to determine the corrosion inhibition efficiency at different concentrations and immersion time periods. Results revealed that the highest inhibition efficiency (94.3%) was achieved at 5 mM concentration after 5 hours of immersion time. To inspect the surface morphology of the inhibitor film on the mild steel surface, scanning electron microscopy (SEM) was used before and after immersion in 1.0 M HCl. Density functional theory (DFT) calculations were performed to investigate the molecular structure and electronic properties of the inhibitor molecule to understand the corrosion inhibition mechanism. Theoretical results showed that the inhibitor molecule can adsorb onto the mild steel surface through its nitrogen and oxygen atoms, forming a protective layer that prevents HCl corrosive attack. These findings highlight the potential of PPDAA as an effective corrosion inhibitor for mild steel in HCl solution. Moreover, combining experimental and theoretical approaches provides insights into the mechanism of corrosion inhibition, which is essential for developing effective strategies to prevent metal corrosion in acidic environments.