• Preventive Nutrition and Food Science
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• 제5권3호
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• pp.131-135
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• 2000

The inhibitory effect of various organic acids on the growth and survival of Escherichia coli O157:H7 in tryptic soy broth with 0.6% yeast extract at 37$^{\circ}C$ or 4$^{\circ}C$ was determined. Minimal inhibitory pHs of acetic acid, citric acid, fumaric acid, hydrochloric acid and lactic acid were 5.0, 4.0, 4.5, 4.0 and 4.5, respectively. Acetic acid (0.012 m) showed the strongest antimicrobial activity, based on the pH values or equivalent molar concentrations, followed by lactic acid (0.0006 M), fumaric acid (0.004M) and citirc acid (0.004 M), respectively, E. coli O157:H7 with an initial inoculum of {TEX}$10^{7}${/TEX} CFU/ml and {TEX}$10^{5}{/TEX} CFU/ml in tryptic soy broth supplemented with 0.6% yeast extract, acidified to target pH with citric, fumaric and lactic acids at 37$^{\circ}C$, was completely inactivated after 7 d and 5 d incubation, respectively, except for the acetic acid (9 d). The bactericidal effect decreased at the same pH when the incubation temperature a was reduced from 37$^{\circ}C$ to 4$^{\circ}C$. The pH values of 0.2% acetic (pH 5.1), 0.6% citric (pH 4.2) and 0.4% lactic acid (pH 4.3) in TSBYE were almost correspondent to the minimal inhibitory pH values on E. coli O157:H7 of acetic (pH 4.0), citric (pH 4.0) and lactic acids (pH 4.5).

• 한국수산과학회지
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• 제46권4호
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• pp.371-376
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• 2013

A feeding trial was conducted to determine the optimum dietary protein and lipid levels for the growth of juvenile muddy loach Misgurnus anguillicaudatus. Eight experimental diets (designated as P20L7, P20L14, P30L7, P30L14, P40L7, P40L14, P50L7 and P50L14) were formulated to contain 20%, 30%, 40% and 50% protein with 7% and 14% lipid. Three replicate groups of muddy loach (1.5 g/fish) were fed one of the experimental diets ad libitum for 8 weeks. Survival of fish fed the P20L14 diet was lower than in other groups (P<0.05). Specific growth rate (SGR) and feed efficiency (FE) of fish were affected by dietary protein (P<0.05) and lipid (P<0.005) levels. SGR and FE of fish tended to decrease with increasing dietary lipid level at the same protein level. There were no significant differences in SGR and FE among fish fed diets containing different protein levels ranging from 30% to 50% with the same lipid level. Whole body moisture and lipid contents were affected by dietary protein and lipid levels. Crude lipid content of fish fed the 14% lipid diets was higher than that of fish fed 7% lipid diets at each protein level. The results of this study indicate that a diet containing 30% protein with 7% lipid would be suitable for the optimum growth and effective feed utilization of juvenile muddy loach.

• Journal of Nutrition and Health
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• 제33권6호
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• pp.647-659
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• 2000

o assess the food intake and the sodium and potassium intakes and urinary excretion of preschool children in Pusan and to evaluate the relationship among variables dietary behaviors food and nutrient intake and 24hr urinary sodium and potassium excretion were measured with 97 subjects. The mean sodium and potassium intakes were 1890. 1mg(82,2meq) and 1479.7mg(37.8meq) respectively. The mean potassium intake(p<0.05) and density(p<0.01) were significantly low at the group who had food intake pattern absen of fruit and daily groups. The mean urinary sodium and potassium excretion were 735.3mg(32.0meq) and 418.7mg(10.7meq) respectively. The mean sodium intake(p<0.01) and urinary excretion were 735.3mg(32.0meq) and 418.7mg(10.7meq) respectively. The mean sodium intake(p<0.01) and urinary excretion (p<0.001, p<0.001) energy intake(p<0.01) sodium intake and density (p<0.001, p<0.05) the food number and intake frequency of vegetable group consumed (p<0.01, p<0.01) dietary frequency score(p<0.05) and negative correlations with the food number and frequency of dairy group consumed (p<0.05 p<0.05) The urinary potassium excretion showed positive correlations with height and weight(p<0.05, p<0.01) urine volume and urinary creatinie excretion(p<0.01 p<0.001) potassium intake(p<0.05) food number and intake frequency of dairy group consumed (p<0.05, p<0.001). Based on the results urinary sodium excretion was related to age sodium intake and food intake of vegetable and dairy group and urinary potassium excretion was related to potassium intake and food intake of dairy group. So nutritional education is needed in order to decrease sodium intake especially from food intake of vegetable group when preschool children have less food intake of diary group,.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.157-160
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• 2002

The dosage of intra-operative BNCT using near-threshold $^{7}$ Li(p,n)$^{7}$ Be direct neutrons was evaluated with the calculation method validated with the phantom experiment. The production of both neutrons by near-threshold $^{7}$ Li(p,n)$^{7}$ Be and gamma rays by $^{7}$ Li(p,p'gamma)$^{7}$ Li in a Li target was calculated using Lee's method and their transport in the phantom was calculated with MCNP-4B. As a result, the region satisfying the requirements of the protocol in intra-operative BNCT for brain tumors in Japan was acknowledged to be comparable to present BNCT, for the proton energy of 1.900 MeV for example. A boron-dose enhancer (BDE) introduced in this study to increase $^{10}$ (n,$\alpha$)$^{7}$ Li dose in a living body was effective. The void used to increase doses in deep regions was also valid with the BDE. It was found that intra-operative BNCT using near-threshold $^{7}$ Li(p,n)$^{7}$ Be direct neutrons is feasible.

• 대한화학회지
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• 제18권6호
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• pp.430-436
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• 1974

여러 pH에서 1,1-dicyano-2-p-dimethylaminophenyl-2-chloroethylene(DPC)의 가수분해 속도상수를 측정하고 넓은 pH 범위에서 잘 맞는 반응 속도로식을 구하였다. 이 식에 의하면 넓은 pH 범위에서 DPC에 대한 가수분해 반응메카니즘을 잘 설명할 수 있다. pH3이하와 7.5이상에서는 속도상수는 hydronium ion과 hydroxide ion 농도에 각각 비례한다. 또 pH 3∼7.5 사이에서는 물, hydronium ion 과 hydroxide ion이 DPC의 가수 분해에 촉매 역활을 함을 알았다.

• 한국항해항만학회지
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• 제36권6호
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• pp.513-519
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• 2012

오염 원인 물질의 해양 내 거동에 대한 파악은 환경 변화에 따른 부영양화 등 해양 수질 오염에 대한 예측 및 대응 방안 선정을 위한 전제 조건이다. 본 연구에서는 부영양화 원인 물질인 인의 해양퇴적물에서 해수로의 용출 특성을 조사하였다. 검토된 환경 조건은 pH 7-9, 온도 10-$20^{\circ}C$, 용존 산소 농도(dissolved oxygen, DO) 0.7-7.0 mg/L 였다. 생물학적 요인을 배제한 조건에서 회분식 실험을 통해 구해진인 용출 자료는 1차 반응식으로 해석되었으며, 환경 조건의 영향은 통계학적 방법을 통해 정량화 되었다. 해양 퇴적물로부터 해수로의 인 용출은 pH와 온도가 높고 DO가 낮을수록 증가하였다. 1차 반응 평형 농도 기준으로 검토된 범위의 pH 증가, 온도 증가, DO 감소는 각각 인용출을 2-3배 증가시켰다.

• The Korean Journal of Physiology and Pharmacology
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• 제10권1호
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• pp.7-11
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• 2006

Interstitial cells of Cajal (ICCs) are pacemakers in gastrointestinal tracts, regulating rhythmicity by activating nonselective cation channels (NSCCs). In the present study, we investigated the general characteristics and pH-mediated regulation of pacemaker activity in cultured interstitial cells of Cajal. Under voltage clamp mode and at the holding potential of -60 mV, the I-V relationships and difference current showed that there was no reversal potential and voltage-independent inward current. Also, when the holding potentials were changed from +20 mV to -80 mV with intervals of 20 mV, there was little difference in inward current. In pacemaker activity, the resting membrane potential (RMP) was depolarized (In pH 5.5, $23{\pm}1.5$ mV depolarized) and the amplitude was decreased by a decrease of the extracellular pH. However, in case of increase of extracellular pH, the RMP was slightly hyperpolarized and the amplitude was decreased a little. The melastatin type transient receptor potential (TRPM) channel 7 has been suggested to be required for intestinal pacemaking activity. TRPM7 produced large outward currents and small inward currents by voltage ramps, ranging from +100 to -100 mV from a holding potential of -60 mV. The inward current of TRPM7 was dramatically increased by a decrease in the extracellular pH. At pH 4.0, the average inward current amplitude measured at -100 mV was increased by about 7 fold, compared with the current amplitude at pH 7.4. Changes in the outward current (measured at +100 mV) were much smaller than those of the inward current. These results indicate that the resting membrane potential of pacemaking activity might be depolarized by external acidic pH through TRPM7 that is required for intestinal pacemaking activity.

• Asian-Australasian Journal of Animal Sciences
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• 제20권11호
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• pp.1670-1676
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• 2007

Fifty repeat breeder (RB) Friesian cows were allocated to five groups of 10 cows each, to determine the effect of progesterone (P4) supplement on P4 concentrations and pregnancy rates during the periods of corpus luteum (CL) formation and development between days 2-7 and 7-12 following a spontaneous or $PGF_{2{\alpha}}$-induced estrus. Cows were artificially inseminated during $PGF_{2{\alpha}}$-induced (PGF-P4-d2 and PGF-P4-d7 groups) or spontaneous (S-P4-d2, S-P4-d7, and control groups) estrus. Progesterone-releasing intravaginal device (PRID) devoid of estrogen capsule were inserted either on d 2 (PGF-P4-d2 and S-P4-d2 groups) or d 7 (PGF-P4-d7 and S-P4-d7 groups) post-insemination and left in place for 5 days. Control cows did not receive any treatment. Blood samples were collected for progesterone analysis from all cows once daily for 4 days starting on the day of estrus (d 0) and once every 3 days thereafter until d 22. Progesterone treatment by day interaction accounted for higher plasma P4 in treated than non-treated control cows. Progesterone concentrations differed significantly (p<0.05) during metestrus (d 2 to d 7) but not during diestrus (d 7 to d 12). $PGF_{2{\alpha}}$ treatment, lactation number, service number or their interactions did not affect progesterone concentrations and pregnancy rates. Therefore, cows were grouped according to the day of P4 supplement irrespective of the $PGF_{2{\alpha}}$ treatment. Progesterone supplement on d 7 but not d 2 significantly increased (p<0.03) pregnancy rates in repeat breeding cows with four or more previous services but not in cows in their third service. In conclusion, post-insemination P4 supplement to repeat breeding cows with four or more previous services improved pregnancy rates and should be advocated when no specific reason for infertility is diagnosed. Further studies with larger numbers of repeat breeding cows under field conditions are needed to ascertain the findings of this study.

• 한국가금학회지
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• 제48권1호
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• pp.31-39
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• 2021

본 연구는 White Leghorn에서 부화 후 일령(0-d, 3-d, 7-d, 14-d 및 21-d)에 따른 소화기관의 발달과 기능 및 항산화 방어작용에 대한 변화를 조사하기 위해 실시하였다. 일령에 따른 체중은 부화 후 0, 3 및 7일령까지는 변화가 적었지만, 7일령 이후에는 유의하게(P<0.05) 증가하였다. 체중에 따른 소화 장기의 상대적 무게(g/100 g BW)에서, 간의 상대적 무게는 0일령에서 현저히 낮았지만 3~7일령에 현저히 증가한 후(P<0.05) 21일령까지 유의차 없이 점차 감소하였다. 상대적 췌장 무게 역시 간 무게의 변화와 유사한 경향을 보이며, 7일령에서 최대 발달을 보였지만(P<0.05) 그 이후에는 점차 감소하는 경향을 보였다. 상대적 소장 무게와 길이의 변화는 부화 후 급격히 증가하여 7일령에서 최대 성장을 보이고(P<0.05) 점차 감소하여 21일령 이후에는 현저히 낮아졌다. 소장 점막세포의 무게는 부화 후 현저히 증가하여(P<0.05) 14일령에 최대 발달률을 보였으나 21일령에는 감소하였다(P<0.05). 이당류 분해효소의 특이적 활성도는 0일령에 가장 낮았으나, 3일령에서 유의적으로 높은 최대 활성도 증가를 보였다(P<0.05). Sucrase 활성도는 14일령 이후 유의하게 감소하였으나(P<0.05), maltase는 지속적으로 높은 활성도를 유지하는 것으로 나타났다. Leucine aminopeptiase 특이적 활성도는 0일령부터 높게 나타나 일령에 상관없이 일정하게 유지되는 것으로 나타났다. SOD와 GST 특이적 활성도는 0일령에서 가장 낮았으나, 7일령 이후 유의적으로 높은 활성도를 보였다(P<0.05). GPX 활성도는 0, 7일령과 비교 시 14일령 이후 활성도가 현저하게 증가하였다(P<0.05). 지질 과산화(MDA) 함량은 모든 일령에서 매우 낮게 나타나 일령에 따른 차이가 없었다. 이상의 결과로 보아, White Leghorn 병아리는 부화 후 3~7일령에서 소화 장기 발달과 소화 효소 활성도가 급격히 증가하며, 7일령 이후 체 성장과 간 조직의 대사 작용이 활발해지면서 항산화 효소의 활성도가 함께 증가하는 것으로 나타났다.

• 분석과학
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• 제21권1호
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• pp.20-24
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• 2008

본 연구에서는 lucigenin과 $H_2O_2$에 의한 화학발광을 이용하여 vitamin $P_1$을 정량하는 방법에 대하여 연구하였다. 분석의 최적 조건을 구하기 위해서 화학발광에 영향을 미치는 $H_2O_2$의 농도, pH 그리고 lucigenin의 농도를 조사하였다. 이러한 분석 최적조건의 검정곡선에서 직선성이 성립하는 범위는 $7.5{\times}10^{-6}$에서 $5.0{\times}10^{-4}mol/L$이었고, 검정곡선에서 직선성이 성립하는 농도구간에서 구한 검출한계는 $5.7{\times}10^{-7}mol/L$이었다. 최적 vitamin $P_1$의 농도인 $7.5{\times}10^{-5}mol/L$에서의 상대표준편차는 0.75%(n=10), 상관계수(S/N=3)는 0.9984이었다.