• Title/Summary/Keyword: Initial growth

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Development of Predictive Growth Model of Listeria monocytogenes Using Mathematical Quantitative Assessment Model (수학적 정량평가모델을 이용한 Listeria monocytogenes의 성장 예측모델의 개발)

  • Moon, Sung-Yang;Woo, Gun-Jo;Shin, Il-Shik
    • Korean Journal of Food Science and Technology
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    • v.37 no.2
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    • pp.194-198
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    • 2005
  • Growth curves of Listeria monocytogenes in modified surimi-based imitation crab (MIC) broth were obtained by measuring cell concentration in MIC broth at different culture conditions [initial cell numbers, $1.0{\times}10^{2},\;1.0{\times}10^{3}\;and\;1.0{\times}10^{4}$, colony forming unit (CFU)/mL; temperature, 15, 20, 25, 37, and $40^{\circ}C$] and applied to Gompertz model to determine microbial growth indicators, maximum specific growth rate constant (k), lag time (LT), and generation time (GT). Maximum specific growth rate of L. monocytogenes increased rapidly with increasing temperature and reached maximum at $37^{\circ}C$, whereas LT and GT decreased with increasing temperature and reached minimum at $37^{\circ}C$. Initial cell number had no effect on k, LT, and GT (p > 0.05). Polynomial and square root models were developed to express combined effects of temperature and initial cell number using Gauss-Newton Algorism. Relative coefficients of experimental k and predicted k of polynomial and square root models were 0.92 and 0.95, respectively, based on response surface model. Results indicate L. monocytogenes growth was mainly affected by temperature and square root model was more effective than polynomial model for growth prediction.

Transient Breakup Phenomena of Initial Spray from High-Pressure Swirl Injector (와류형 고압인젝터의 초기분무의 분열 과도현상)

  • Choi, Dong-Seok;Kim, Duck-Jool;Ko, Chang-Kwon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.8
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    • pp.1132-1140
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    • 1998
  • The disintegration process of initial spray from high-pressure swirl injector was investigated at different injection pressures. The transient breakup phenomena that were difficult to observe at high injection pressure were easily observed at the low injection pressure of 0.4MPa. The effect of fuel remained inside a nozzle hole volume on the penetration of initial spray was also investigated. The disintegration process of initial spray could be classified four regions: the formation of mushroom shape, the first collision, the second collision, and the development of spray, The liquid film of cup shape was particularly found in the second collision region, and the growth ratio of its length and width at low and high injection pressures were compared.

A Longitudinal Study on the Correlation between School-life Adjustment and Suicidal Ideation in Adolescents based on the Korean Children and Youth Panel Survey (청소년의 학교생활적응과 자살생각에 관한 종단적 관계연구: 한국아동·청소년패널조사를 중심으로)

  • Yang, Su Jeong;Lee, Jong-Eun
    • Research in Community and Public Health Nursing
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    • v.31 no.1
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    • pp.86-95
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    • 2020
  • Purpose: The aim of this study was to examine the correlation between school-life adjustment and suicidal ideation in adolescents by applying the latent growth curve models to the longitudinal data. Methods: This study analyzed three waves of data from the Korean Children & Youth Panel Survey (2014~2016). A total of 1,534 students were included in the analysis. In the application of the latent growth curve models to the longitudinal survey data, we analyzed the initial status and growth changes for each wave, identified individual differences in the general characteristics, and examined the direct relationship between the two latent constructs. Results: The analysis revealed that variations in the initial status and rate of school-life adjustment were significant with respect to parents' education level, household income and academic satisfaction. Variations in the initial status and growth rate of suicidal ideation were significantly associated with household income and family structure. The relationship between school-life adjustment and suicidal ideation showed a negative correlation in which the starting value of the former increased and that of the latter decreased and vice versa. Conclusion: The results confirmed that school-life adjustment and suicidal ideation varied according to students' general characteristics. In addition, school-life adjustment was negatively correlated with suicidal ideation, thereby highlighting students' ability to adjust as an important factor influencing their suicidal thinking.

Production of 10-deacetylbaccatin III in Taxus cuspidata Suspension Cell Culture (주목 현탁세포배양을 이용한 10-deacetylbaccatin III 생산)

  • Lee, Gue-Wha;Kim, Dong-Il
    • KSBB Journal
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    • v.14 no.6
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    • pp.665-671
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    • 1999
  • In this study, enhanced production of 10-deacetylbaccatin III(10-DAB), a precursor of taxol in semisynthesis, was investigated in Taxus cuspidata cell suspension cultures. The effects of initial inoculum size and sugar concentration were examined to prove the relationship between the production of 10-DAB and cell growth. The cell growth was found to be stimulated in Schenk and Hildebrandt(SH) medium. The lower the inoculum size as well as initial sugar concentration, the faster the cell growth rate. When the initial sugar concentration was dept low, the production of 10-DAB into medium was increased. By using perfusion culture, continuous cell growth was possible until the end of culture and more than 34.67 g/L of cell concentration could by obtained. This is about 2.5 times higher level than that of control batch culture.

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Growth Rate and Biomass Productivity of Chlorella as Affected by Culture Depth and Cell Density in an Open Circular Photobioreactor

  • Liang, Fang;Wen, Xiaobin;Geng, Yahong;Ouyang, Zhengrong;Luo, Liming;Li, Yeguang
    • Journal of Microbiology and Biotechnology
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    • v.23 no.4
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    • pp.539-544
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    • 2013
  • The effects of culture depth (2-10 cm) and cell density on the growth rate and biomass productivity of Chlorella sp. XQ-200419 were investigated through the use of a self-designed open circular pond photobioreactor-imitation system. With increases in culture depths from 2 to 10 cm, the growth rate decreased significantly from 1.08 /d to 0.39 /d. However, the biomass productivity only increased slightly from 8.41 to 11.22 $g/m^2/d$. The biomass productivity (11.08 $g/m^2/d$) achieved in 4 cm culture with an initial $OD_{540}$ of 0.95 was similar to that achieved in 10 cm culture with an initial $OD_{540}$ of 0.5. In addition, the duration of maximal areal productivity at a 4 cm depth was prolonged from 1 to 4 days, a finding that was also similar to that of the culture at a 10 cm depth. In both cases, the initial areal biomass densities were identical. Based on these results and previous studies, it can be concluded that the influence of culture depth and cell density on areal biomass productivity is actually due to different areal biomass densities. Under suitable conditions, there are a range of optimal biomass densities, and areal biomass productivity reaches its maximum when the biomass density is within these optimal ranges. Otherwise, biomass productivity will decrease. Therefore, a key factor for high biomass productivity is to maintain an optimal biomass density.

Growth Factor According to Rebleeding in Small Volume Spontaneous Intracerebral Hemorrhage (소량의 자발성 뇌내출혈에서 재출혈에 의한 혈종 성장에 미치는 인자)

  • Jung, Hyun Ho;Kim, Sei Yoon;Whang, Kum;Cho, Sung Min;Pyen, Jhin Soo;Hu, Chul;Hong, Soon Ki
    • Journal of Korean Neurosurgical Society
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    • v.30 no.sup2
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    • pp.259-265
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    • 2001
  • Objectives : Spontaneous intracerebral hemorrhage(S-ICH) is generally considered to be a mon-ophasic event. But some patients with ICH continued to bleed even after hospitalization. In order to evaluate the rebleeding and growth factor of hematoma in small volume S-ICH, 125 cases of S-ICH were reviewed retrospectively. Methods : We assesed age, sex, initial mental state, location of hemorrhage, systolic and diastolic blood pressure, blood pressure patterns, hematologic profile, trauma and stroke history, alcohol consumption and smoking history. Two subgroups-rebleeding groups versus no rebleeding groups-were compared, in terms of data analysis, with student T-test and chi-square test. Results : Substantial growth in the volume of S-ICH occurred in 21 cases(16.8%)-putamen(7 cases), thalamus(6 cases), subcortex(5 cases), cerebellum(2 cases), pons(1 case)-of the 125 patients. There was no significant difference in any of the parameters except initial systolic blood pressure(p=0.037) when patients with and without rebleeding were compared. Conclusion : The rebleeding and growth of the small volume S-ICH was related to the markedly elevated initial systolic blood pressure(${\geq}180mmHg$) and labile pattern of blood pressure.

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Optimization of Fermentation Process for Acetic Acid Production (초산 생성을 위한 발효공정의 최적화)

  • Shin, Jin-A;Oh, Nam-Soon
    • Food Engineering Progress
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    • v.14 no.3
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    • pp.217-221
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    • 2010
  • Various conditions of acetic acid fermentation by Acetobacter aceti B20 strain were investigated and evaluated to optimize the fermentative production of acetic acid. The effects of the initial ethanol concentration on growth and acid productivity in a flask and fermentor were also studied. The growth of A. aceti B20 strain was inhibited as the concentration of ethanol increased. However, the highest total acidity and fermentation yield were 5.34% and 56.1%, respectively when the initial concentration of ethanol was 7% in the batch fermentation. Although the concentration of initial glucose influenced the growth rate of B20 strain, it did not influence the total acidity in the flask culture. When the agitation speed increased, the growth, total acidity and fermentation yield were all improved. In fed-batch fermentation, total acidities and fermentation yields were 7.14-8.76% and 39.1-53.0%, respectively, and their values mostly depended on the feeding methods.

A Study on the Influence of Socio-economic Deprivation on Depression : Focusing on Latent Growth Modeling Analysis (사회경제적 박탈이 우울에 미치는 영향에 관한 연구: 잠재성장모형 분석을 중심으로)

  • Sohn, Yong Jin
    • Journal of the Korean Data Analysis Society
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    • v.20 no.6
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    • pp.3227-3238
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    • 2018
  • This study attempts to investigate the trajectories of socio-economic deprivation on the depression trajectories among middle-aged individuals using a latent growth model over the last five years. Using the Korea welfare panel study data ranged from the year 2013 (8th wave) to the year 2017 (12th wave), a sample of 7,437 aged over 40 was selected. Three hypothesis was proposed as follows. Is the trajectory of depression changing over the years? Are the initial values of socio-economic deprivation causally related to the initial values of depression? Are the rates of change in socio-economic deprivation causally related to the rates of change in depression? Results showed that the growth curve of depression tended to decline negatively over the five-year period. As the intial values of socio-economic deprivation increased, so did the initial values of depression move upwards. Finally, as the changes of socio-economic deprivation tended to get larger, those changes of depression also accordingly increased as well. The public policy implications based on the current study were discussed to pay more attention to those middle-aged individuals suffering from socio-economic deprivations.

The Growth Analysis of the Crawfish (Cambaroides similis Koelbel) (Crustacea) 2. Relative Growth (가재(Cumbaroides similis Koelbel)의 상대성장 분석)

  • 연근성;노용태정병균
    • The Korean Journal of Zoology
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    • v.35 no.2
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    • pp.231-239
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    • 1992
  • For the analysis of the relative grouch of six body pans, such as carapace width. abdominal length, abdominal width, cheliped length, second pereiopod length and third pereiopod length, to the carapace length of crayfish (Comboroides similis Koelbel), the equation Y = bXa were applied. The results were as follows: 1. In the relative srourth of each body part to the carapace length, abdominal width and abdomial length in both sexes showed as positive allometrv, the third pereiopod length in both sexes as isometry and the rest shouted as negative. The least coefficient of the relative growth was found in cheliped length in female (0.9300).2. The grolwth gradient of each body part to the carapace length in each sex revealed decreasing pattern in abdominal length and third pereiopod length in both sexes and the abdominal width in male with the growth centers on the initial growth period. and the rest showed increasing pattern with the growth centers on the 6th growvth period except the abdomini,d uridth in female on the 3rd growth period.

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The effect of parental rearing behavior on self-esteem and gender role Stereotypes in Adolescents: Mediating effect of self-esteem -The use of Latent Growth Model-

  • Ju, Sunyoung
    • Journal of the Korea Society of Computer and Information
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    • v.24 no.6
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    • pp.189-197
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    • 2019
  • The purpose of this study was to investigate about the effects of parental rearing behavior on self-esteem and gender role stereotype during adolescence and to reveal the mediating effect of self-esteem on adolescents' gender role strerotype. Also investigated the relationship among these variables and condition variables. For this purpose, used the Second Grade longitudianl Panel data of Middle School from the Korea Youth Panel Survay(KYPS). And the latent growth model was analyzed 3,449 men and women adolescents' cases of the first, the fourth and the sixth wave of the Korea Youth Panel Survey(KYPS) administered by Korea Institute for Youth development. And the structural equation model was used to investigate whether self-esteem mediates parental rearing behavior and male and female gender role Strerotype. The results of this study, the direct effect between variable factors showed that the more positive the parenting behavior of the second grader of middle school is, the more positive the self-esteem of male adolescents and the initial value of stereotypes of male gender role. It also affects the self-esteem of female adolescents and stereotypes of female gender roles but not statistically significant. The male gender role stereotypes were decreased in influence by the rate of change of parental rearing behaviors, and the initial value and the rate of change of self-esteem were statistically influenced to the male gender role stereotypes and the higher the self-esteem, the higher the self-esteem. However, there was no significant effect on stereotypes of female gender roles. As a result of analyzing the mediating effect of self-esteem, partially mediated between the initial value of parental rearing behavior and initial stereotype of male gender role, but there was no longitudinal mediation effect. There was no mediating effect of self-esteem between parental rearing behaviors and stereotypes of female gender roles and there was no longitudinal mediation effect. The effect of condition variable gender was found that female adolescents are more affected by paretal rearing behavior than male adolescents and also affected by the growth process. The monthly income of households influenced the initial value of parental rearing behaviors and showed a difference in parental rearing behavior according to household income. And the higher the mother 's educational level, the more the self-esteem of male adolescents was affected.