• Journal of Food Hygiene and Safety
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• v.28 no.2
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• pp.168-173
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• 2013

This study was carried out to develop and validate predictive models of E. coli O157:H7 growth. Growth data of E. coli O157:H7 in Paprika were collected at 12, 24, 30 and $36^{\circ}C$. The population increased into 3.0 to 3.8 log10 CFU/g within 4 days, then continued to increase at a slower rate through 10 days of storage at $12^{\circ}C$. The lag time (LT) and maximum specific growth rate (SGR) obtained from each primary model was then modeled as a function of temperature using Davey and square root equations, respectively. For interpolation of performance evaluation, growth data for a mixture of E. coli O157:H7 were collected at time intervals in paprika incubated at the different temperatures, which was not used in model development. Results of model performance for interpolation data demonstrated that induced secondary models showed acceptable goodness of fit. Relative errors in the LT and SGR model for interpolation data (18 and $27^{\circ}C$) was 100%, which show acceptable goodness of fit and validated for interpolation. The primary and secondary models developed in this study can be used to establish tertiary models to quantify the effects of temperature on the growth of E. coli O157:H7 in paprika.

• Journal of Microbiology and Biotechnology
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• v.15 no.6
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• pp.1323-1329
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• 2005

A mathematical model was developed for predicting the growth kinetics of Listeria monocytogenes in tryptic soy broth (TSB) as a function of combined effects of temperature, pH, and NaCl. The TSB containing four different concentrations of NaCl (2, 4, 5, and $10\%$) was initially adjusted to six different pH levels (pH 5, 6, 7, 8, 9, and 10) and incubated at 4, 10, 25, or 37$^{circ}C$. In all experimental variables, the primary growth curves were well fitted ($r^{2}$=0.982 to 0.998) to a Gompertz equation to obtain the lag time (LT) and specific growth rate (SGR). Surface response models were identified as appropriate secondary models for LT and SGR on the basis of coefficient determination ($r^{2}$=0.907 for LT, 0.964 for SGR), mean square error (MSE=3.389 for LT, 0.018 for SGR), bias factor ($B_{1}$B,=0.706 for LT, 0.836 for SGR), and accuracy factor ($A_{f}$=1.567 for LT, 1.213 for SGR). Therefore, the developed secondary model proved reliable predictions of the combined effect of temperature, NaCl, and pH on both LT and SGR for L. monocytogenes in TSB.

• The Journal of Internal Korean Medicine
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• v.30 no.2
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• pp.288-297
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• 2009

Objective : Inflammatory cytokines have a close relationship to insulin dependent diabetes mellitus (IDDM). The inhibitory effect of Smilacis Glabrae Rhizoma (SGR) were examined on production of nitric oxide (NO), prostaglandin $E_2$ $(PGE_2)$, synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and NF-${\kappa}$B activation in Raw 264.7 cells. Methods: Raw 264.7 cells were pretreated with SGR(20, 50, 100 ${\mu}g$/ml), and then cultured with lipopolysaccharides (LPS). Cell viability was measured by MTT assay; inhibition of NO, $PGE_2$, and TNF-${\alpha}$ production were measured by Griess reagent and enzyme-linked immunosorbent assay(ELISA). Induction of COX-2 and iNOS were determined by western blotting analysis. Inhibition of NF-${\kappa}$B was measured by immunofluorescence assay (IFA). Results: SGR inactivated NF-${\kappa}$B, and inhibited the production of NO, iNOS, and $PGE_2$. Inhibition of COX-2 and TNF-${\alpha}$ could not be confirmed. Conclusions: From the above result. SGR was found to have an anti-inflammatory effect of inhibition of NO, iNOS, and $PGE_2$ production via inhibition of NF-${\kappa}$B.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.41.1-41.1
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• 2016

The Galactic center, Sagittarius A* (Sgr A*), is the closest supermassive black hole and emits synchrotron radiation. It provides great opportunity to study the origin of mm/sub-mm emission. Currently, two competing models have been suggested as a jet base and a radiatively inecient accretion flow (RIAF). To unveil the properties, the extremely high resolution(${\sim}10{\mu}as$) corresponding to the projected Schwarzschild radius of ~0.1AU is necessary. With KVN, a jet model can be tested by multi- frequency simultaneous observations because the optically thick surface in a jet (i.e. radio core) moves toward the center at a higher frequency. We conducted 8 observations with KVN at 43/86GHz in 2015, and found that the measured positional shift to the reference calibrator, J1744-3116, was ~0.3 mas to the south of Sgr A* using the source frequency phase referencing (SFPR) at Q/W bands for the first time. With the result, in the future, we will attempt to measure the variation of source position shifts that can constrain the direction of approaching jets and the variability of black hole activity of Sgr A*.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.1
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• pp.27-33
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• 2011

In this paper, for a software-based Global Positioning System receiver (SGR), the principle capturing Global Positioning System (GPS) signal is researched extensively in order to analyze the processing of the GPS raw data signal at the lowest level, and the process of capturing the GPS signal was simulated by Matlab. The simulation results show the accuracy and the feasibility of this method, which is comparable to study under a true environment. We know that the improvement of the receiving facilities is of very vital significance to the performance of this system, and the fine frequency can be found through comparing phases within a few tens of Hertz.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.836-843
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• 2009

The Water Glass grouting method has been applied frequently to impermeable grouting in practice. But there is raising problems which are durability decrease by passage time and environmentally adverse effect. So, Earth Natural Grouting method which uses micro cement is developed to overcomes the problems of the Water Glass grouting method. And it is displayed ground injection extent like Water Glass grouting method. For verifying impermeability of ENG, it is carried out a triaxial permeability test about manufacturing specimen of ENG, SGR method which is a presentative Water Glass grouting method. Although Coefficient of permeability, k, of SGR is measured a little high than k of ENG whose value is $a{\times}10^{-6}cm/sec$, the value of ENG belong to impermeable rage. And, k of SGR shows relatively rapid increase according to cure time due to durability decrease of water glass. Also, in-situ test result of ENG has similar value with SGR method for similar ground.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.73.2-73.2
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• 2016

We present the results of KaVA SgrA* observation together with Takahagi(32m), Yamaguchi(32m) and Nobeyama(45m) telescopes at 22 and 43GHz, respectively. In early 2014, G2 cloud was expected to encounter with SgrA* and to make a significant flux variation, but it has not been measured yet. So it's worth to check our amplitude calibration method to confirm if we have a missing flux caused by uncertainty in measuring it. We have tested both a standard method using system noise temperature(Tsys) with antenna gain information, and a template method in order to calibrate antenna gain using nearby maser source. As a result, we found that the latter method is useful for antennas which have inaccurate gain information or poor Tsys measurements, and is especially effective for sources at low elevation like SgrA*. In addition, the comparison shows that the amplitude calibration by standard method can be improved up to 10% with a correction factor using a template method. This result implies we can get more accurate flux from a standard method when any maser source not exists around target.

• Journal of The Korean Astronomical Society
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• v.26 no.1
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• pp.73-78
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• 1993

We have mapped the $C_3H_2\;2_{12}-1_{01}$ transition line toward the Sgr A molecular cloud on a 1' grid spacing and derived $C_3H_2$ column densities of $3\~7\times10^{14}\;cm^{-2}$ for molecular clouds of Sgr A. The fractional abundances of $C_3H_2$ relative to $H_2$ are obtained to be $3\~6\times10^{-9}$, which are slightly lower than that for the cold dark cloud TMC-1 but are enhanced by factors of 5-60 compared to those for Sgr B2 and the Orion extended ridge. We also estimate from the $C_3H_2$ column densities total masses of $\~10^6\; M_\bigodot$ for two clouds (M - 0.13 - 0.08 and M - 0.02 - 0.07), which are thought to be close to the virial equilibrium. We suggest that the large abundance of $C_3H_2$ in Sgr A may be partly due to the activities of the Galactic center.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.715-720
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• 2006

This study was performed to develop a predictive model for the growth kinetics of Listeria monocytogenes in tryptic soy broth (TSB) using a response surface model with a combination of potassium lactate (PL), temperature, and pH. The growth parameters, specific growth rate (SGR), and lag time (LT) were obtained by fitting the data into the Gompertz equation and showed high fitness with a correlation coefficient of $R^2{\geq}0.9192$. The polynomial model was identified as an appropriate secondary model for SGR and LT based on the coefficient of determination for the developed model ($R^2\;=\;0.97$ for SGR and $R^2\;=\;0.86$ for LT). The induced values that were calculated using the developed secondary model indicated that the growth kinetics of L. monocytogenes were dependent on storage temperature, pH, and PL. Finally, the predicted model was validated using statistical indicators, such as coefficient of determination, mean square error, bias factor, and accuracy factor. Validation of the model demonstrates that the overall prediction agreed well with the observed data. However, the model developed for SGR showed better predictive ability than the model developed for LT, which can be seen from its statistical validation indices, with the exception of the bias factor ($B_f$ was 0.6 for SGR and 0.97 for LT).

• Journal of the Korean GEO-environmental Society
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• v.13 no.7
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• pp.31-38
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• 2012

Water glass chemical grouts are primarily used in ground injection projects. Natural and Durable Stabilizer (NDS), Space Grout Rocket (SGR), and other similar materials composing of inorganic accelerating agents with ultra fine cement have been gaining popularity as ground improvement material in South Korea. However, there are questions as to grouting results and environmental issues caused by NDS grout. This study uses the injection method in mudstone embarkment to evaluate the differences in strength, permeability, and optimum injection volume through the use of uniaxial and triaxial compression tests and fish poison tests for NDS and SGR materials. After 28 days, results showed SGR and NDS to have a 50% increase in strength and 50% decrease in permeability with the proper injection rate at 50%.