• Asian-Australasian Journal of Animal Sciences
• /
• 제16권6호
• /
• pp.894-902
• /
• 2003

Prebiotics (peptides, N-acetyglucoamine, fructo-oligosaccharides, isomalto-oligosaccharides and galactooligosaccharides) were added to skim milk in order to improve the growth rate of contained Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium longum and Bifidobacterium bifidum. The purpose of this research was to study the potential synergy between probiotics and prebiotics when present in milk, and to apply modern optimization techniques to obtain optimal design and performance for the growth rate of the probiotics using a response surface-modeling technique. To carry out response surface modeling, the regression method was performed on experimental results to build mathematical models. The models were then formulated as an objective function in an optimization problem that was consequently optimized using a genetic algorithm and sequential quadratic programming approach to obtain the maximum growth rate of the probiotics. The results showed that the quadratic models appeared to have the most accurate response surface fit. Both SQP and GA were able to identify the optimal combination of prebiotics to stimulate the growth of probiotics in milk. Comparing both methods, SQP appeared to be more efficient than GA at such a task.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제10권3호
• /
• pp.192-197
• /
• 2005

The effects of macronutrients $(NO_3^-,\; NH_4^+\;and\;PO_4^{3-})$ on cell growth and triterpenoids production in Centella asiatica cell suspension cultures were analyzed using the Box­Behnken response surface model experimental design. In screening and optimization experiments, $PO_4^{3-}$ as a single factor significantly influenced cell growth where increasing the phosphate level from 0.1 to 2.4 or 2.6 mM, elevated cell growth from 3.9 to $14\~16g/L$. The optimum values predicted from the response surface model are 5.05mM $NH_4^+$, 15.0mM $NO_3^-$ and 2.6mM $PO_4^{3-}$, yielding 16.0g/L cell dry weight with $99\%$ fitness to the experimental data. While the $NH_4^+-NO_3^-$ interaction influenced cell growth positively in the optimization experiment, $NH_4^+$ and $NO_3^-$ as single factors; and interactions of $NO_3^--PO_4^{3-},\;NH_4^+-PO_4^{3-}$ and $NH_4^+-NO_3^-$ were all negative in the screening experiment. Cell growth and the final pH level were positively affected by $PO_4^{3-}$, but negatively affected by $NH_4^+\;and\;NH_4^+-PO_4^{3-}$ interactions. The different effects of factors and their interactions on cell growth and final pH are influenced by a broad or narrow range of macronutrient concentrations. The productions of triterpenoids however were lower than 4mg/g cell dry weight.

• Journal of Microbiology and Biotechnology
• /
• 제17권9호
• /
• pp.1437-1444
• /
• 2007

A response surface model was developed for predicting the growth rates of Staphylococcus aureus in tryptic soy broth (TSB) medium as a function of combined effects of temperature, pH, and NaCl. The TSB containing six different concentrations of NaCl (0, 2, 4, 6, 8, and 10%) was adjusted to an initial of six different pH levels (pH 4, 5, 6, 7, 8, 9, and 10) and incubated at 10, 20, 30, and $40^{\circ}C$. In all experimental variables, the primary growth curves were well ($r^2=0.9000$ to 0.9975) fitted to a Gompertz equation to obtain growth rates. The secondary response surface model for natural logarithm transformations of growth rates as a function of combined effects of temperature, pH, and NaCl was obtained by SAS's general linear analysis. The predicted growth rates of the S. aureus were generally decreased by basic (pH 9-10) or acidic (pH 5-6) conditions and higher NaCl concentrations. The response surface model was identified as an appropriate secondary model for growth rates on the basis of correlation coefficient (r=0.9703), determination coefficient ($r^2=0.9415$), mean square error (MSE=0.0185), bias factor ($B_f=1.0216$), and accuracy factor ($A_f=1.2583$). Therefore, the developed secondary model proved reliable for predictions of the combined effect of temperature, NaCl, and pH on growth rates for S. aureus in TSB medium.

• 한국축산식품학회지
• /
• 제35권6호
• /
• pp.815-823
• /
• 2015

This study developed probabilistic models to describe Listeria monocytogenes growth responses in meat products with low concentrations of NaNO₂ and NaCl. A five-strain mixture of L. monocytogenes was inoculated in NBYE (nutrient broth plus 0.6% yeast extract) supplemented with NaNO₂ (0-141 ppm) and NaCl (0-1.75%). The inoculated samples were then stored under aerobic and anaerobic conditions at 4, 7, 10, 12, and 15℃ for up to 60 d. Growth response data [growth (1) or no growth (0)] for each combination were determined by turbidity. The growth response data were analyzed using logistic regression to predict the growth probability of L. monocytogenes as a function of NaNO₂ and NaCl. The model performance was validated with the observed growth responses. The effect of an obvious NaNO₂ and NaCl combination was not observed under aerobic storage condition, but the antimicrobial effect of NaNO₂ on the inhibition of L. monocytogenes growth generally increased as NaCl concentration increased under anaerobic condition, especially at 7-10℃. A single application of NaNO₂ or NaCl significantly (p<0.05) inhibited L. monocytogenes growth at 4-15℃, but the combination of NaNO₂ or NaCl more effectively (p<0.05) inhibited L. monocytogenes growth than single application of either compound under anaerobic condition. Validation results showed 92% agreement between predicted and observed growth response data. These results indicate that the developed model is useful in predicting L. monocytogenes growth response at low concentrations of NaNO₂ and NaCl, and the antilisterial effect of NaNO₂ increased by NaCl under anaerobic condition.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제10권4호
• /
• pp.304-308
• /
• 2005

The response of IPTG induction was investigated through the monitoring of the alkali consumption rate and buffer capacity during the cultivation of recombinant E. coli BL21 (DE3) harboring the plasmid pRSET-LacZ under the control of lac promoter. The rate of alkali consumption increased along with cell growth, but declined suddenly after approximately 0.2 h of IPTG induction. The buffer capacity also declined after 0.9 h of IPTG induction. The profile of buffer capacity seems to correlate with the level of acetate production. The IPTG response was monitored only when introduced into the mid-exponential phase of bacterial cell growth. The minimum concentration of IPTG for induction, which was found out to be 0.1 mM, can also be monitored on-line and in-situ. Therefore, the on-line monitoring of alkali consumption rate and buffer capacity can be an indicator of the metabolic shift initiated by IPTG supplement, as well as for the physiological state of cell growth.

• 한국양식학회지
• /
• 제16권1호
• /
• pp.31-36
• /
• 2003

사육 염분의 급성교환 실험에서, 해수의 담수화가 1시간 이내에 이루어졌을 경우 농어, 유어들은 다소의 스트레스 반응과 이온의 변화가 있었으며. 24시간 뒤에도 정상 회복이 더딘 것으로 나타났다. 그러나 5시간에 걸친 담수화 과정 중에 스트레스 반응은 담수화 직후 높게 나타났지만, 24시간 후 빠르게 정상으로 회복되는 것을 알 수 있다. 장기간 염분별 사육실험 결과, 20 ppt가 가장 높은 사료섭식량을 나타내었고, 2 ppt구가 가장 낮았다. 사료효율 또한 2 ppt구이 가장 낮게 나타났고, 10 ppt구가 가장 높았으며, 실험구별 유어의 성장은 실험 종료시 10, 20 및 30 ppt구가 2 ppt보다 유의하게 높은 길이 성장을 보였다. 무게 성장은 실험 종료시 20 ppt가 가장 빠른 무게 성장을 나타내었고, 다음으로 30 ppt, 10 ppt. 2 ppt순으로 나타났다. 염분별 사육유어의 혈액 성상은 2 ppt~30 ppt 사육수에 있어 농어 유어들의 혈액 조성은 큰 차이가 없는 것으로 나타났다.

• 대한한방소아과학회지
• /
• 제18권1호
• /
• pp.221-246
• /
• 2004

Objective: The purpose of this study was to investigate the effects of Kamikwiryongtang (KKT) on the immune response and growth in a young mouse (3 weeks mice). Methods The viability of thymocytes and splenocytes in vivo and in vitro system, the population of helper T (Th) cells and cytotoxic T (Tc) cells in thymocytes and increased the population of T-lymphocytes and the population of Th cells in splenocytes, the production of ${\gamma}$ -interferon, interleukin-2 and interleukin-4 in splenocytes was investigated. KKT (500mg/kg) was administerd p.o. once a day for 7 days. Results: KKT increased the viability of thymocytes and splenocytes in vivo, but did not affect the viability of thymocytes and enhanced the viability of splenocytes in vitro system. In addition, KKT did not affect the population of helper T (Th) cells and cytotoxic T (Tc) cells in thymocytes and increased the population of T -lymphocytes and the population of Th cells in splenocytes. Also, KKT increased the production of ${\gamma}$-interferon, interleukin-2 and interleukin-4 in splenocytes. Furthermore, KKT increased the production of nitric oxide in vivo, but did not affect the production of nitric oxide in vitro system. KKT enhanced the phagocytic activity of peritoneal macrophages in vivo, but decreased the phagocytic activity in vitro system: KKT increased the body weight of a young mouse. Conclusions: KKT stimulates the specific immune response via increase of, the viability of thymocytes and splenocytes and the non-specific immune response via increase of phagocytic activity of peritoneal macrophages and stimulates the growth of a young mouse.

• 한국환경복원기술학회지
• /
• 제13권3호
• /
• pp.36-45
• /
• 2010

To analyze the relationship between climatic factors (monthly mean temperature and total precipitation) and tree-ring growths of Quercus mongolica Fischer (Mongolian oak) with different topographic sites in Mt. Worak, more than 10 trees were selected from each of seven stands. Two cores from each tree were measured for ring width. After crossdating, each ring-width series was double standardized by fitting first a negative exponential or straight regression line and secondly a 60-year cubic spline. Seven stands were categorized in two groups using cluster analysis for tree-ring index patterns. Cluster I (four stands) was located in higher elevation (550-812 m) with aspects of east, west and northwest, and cluster II (three stands) was located in rather lower election (330-628 m) with aspects of north and northwest. The aspects of two clusters were not significantly different. Response-function analysis showed a significant positive response to March precipitation for both clusters. It indicates that moisture supply during early spring season is important to radial growth because the cambial growths of ring-porous species, such as Mongolian oak, start before leaf growth. Cluster II showed a positive response to the precipitation of middle and late growing season, too.

• 한국환경과학회지
• /
• 제27권10호
• /
• pp.875-881
• /
• 2018

To select fruit trees suitable for shaded urban garden with Elaeagnus umbellata var. coreana, Malus domestica 'Alps Otome', Malus domestica 'Fujii', Prunus mume, Prunus persica for. persica, Rubus fructicosus, and Vaccinium corymbosum 'Reka', leaf growth in response to different light was investigated two years after 35% shade treatment. Leaf area of E. umbellata var. coreana, M. domestica 'Alps Otome', P. mume, P. persica for. persica, and V. corymbosum 'Reka' increased in shading. Fresh weight of leaves make inconsistent response to shading in every species but dry weight of E. umbellata var. coreana and P. persica for. persica showed the highest 150% and 148%, increment, respectively. Althought leaf water content of E. umbellata var. coreana decreased in shading, there is no difference in P. persica for. persica. Chlorophyll value of E. umbellata var. coreana and P. persica for. persica that showed higher than any other species is correlated with dark leaf green. Compared to specific leaf weight of E. umbellata var. coreana, P. persica for. persica, and V. corymbosum 'Reka' showed lower than any other species in shading, that of M. domestica 'Fujii', and R. fructicosus increased in reverse. These results indicate that E. umbellata var. coreana and P. persica for. persica that showed high value in several invesetigaton items are suitable for shady urban condition considering leaf growth in response to shading.

• 한국화재소방학회논문지
• /
• 제34권4호
• /
• pp.45-51
• /
• 2020

본 연구에서는 스프링클러 헤드의 해석모델을 통해 화재성장모드별 스프링클러 작동시 연층기류의 열유동조건을 파악하고자 한다. 화원은 최대발열량 3 MW의 시간제곱의 화재성장을 가정하였다. 시험대상 스프링클러헤드는 작동온도 65~105 ℃, RTI 25~171 m^1/2s^1/2 범위의 표준형과 조기반응형 8종을 대상으로 한다. 연층기류의 온도와 감열부의 온도차는 화재성장이 느리고 스프링클러 헤드의 RTI값이 작을수록 감소하는 경향을 보였다. 스프링클러 헤드 작동 순간의 연층 기류 온도와 속도조건은 전체적으로 시험기준의 범위와 비교적 잘 일치하고 있으나 저성장 화재에서는 최저시험기준 이하의 온도와 속도조건에서 작동이 이루어질 수 있음을 파악하였다. 본 연구는 스프링클러 헤드의 작동에 대한 기초연구로서 시험기준의 신뢰성을 향상시키는데 기여할 수 있다.