• Journal of Life Science
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• v.18 no.12
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• pp.1625-1630
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• 2008

A microorganism capable of producing high level of poly-3-hydoxybutyrate (PHB) from xylose was isolated from soil. The isolated strain J-65 was identified as Bacillus megaterium based on the morphological, biochemical and molecular biological characteristics. The optimum temperature and pH for the growth of B. megaterium J-65 were $37^{\circ}C$ and 8.0, respectively. The optimum medium composition for the cell growth was 2% xylose, 0.25% $(NH_4)_2SO_4$, 0.3% $Na_2HPO_4{\cdot}12H_2O$, and 0.1% $KH_2PO_4$. The optimum condition for PHB accumulation was same to the optimum condition for cell growth. Copolymer of ${\beta}$-hydroxybutyric and ${\beta}$-hydroxyvaleric acid was produced when propionic acid was added to shake flasks containing 20 g/l of xylose. Fermenter culture was carried out to produce the high concentration of PHB. In batch culture, cell mass was 9.82 g/l and PHB content was 35% of dry cell weight. PHB produced by B. megaterium J-65 was identified as homopolymer of 3-hydoxybutyric acid by GC and NMR.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.6
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• pp.472-481
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• 2000

This experiment used the enclosed bench-scale reactors was conducted to find out optimal aeration rate for reducing the emission of odors and producing the good-quality compost with the mixture of dairy manure and rice straw. The reactors with gas sampler were aerated at four different rates of 0.09, 0.18, 0.90 and $1.79l\;min^{-1}kg^{-1}$dry solids for 574 hours. The oxygen content within composting pile instantly decreased after aeration. Oxygen limitation(below 15%) in the treatments of $0.90l\;min^{-1}kg^{-1}$ and less was exponentially negative relationship with aeration rates and in the range of 35 to 300 hours after aeration. However, the treatment of $1.79l\;min^{-1}kg^{-1}$ didn't show the oxygen limitation. The oxygen consumption rate and the cumulative amount of oxygen consumed by different aeration rates was ranged in $0.80{\sim}1.57O_2g\;h^{-1}\;kg^{-1}VS^{-1}$, $460{\sim}900O_2g\;kg^{-1}VS^{-1}$, respectively, and they were high in the order of 0.90, 1.79, 0.18, $0.09l\;min^{-1}kg^{-1}$. The maximum oxygen consumption rate was estimated in the range of $1.2{\sim}1.3lmin^{-1}kg^{-1}$. The emission concentrations of sulfur compounds such as hydrogen sulfide, sulfur dioxide and methylmercaptan were remarkably high in the initial composting time. Then they were rapidly decreased with the passing of composting time and clearly with increasing aeration rates. Their average concentrations were in the range of 0.03~2.18, 0~0.50, $0.07{\sim}3.38mg\;kg^{-1}$, respectively and high in the order of methylmercaptan, hydrogen sulfide, and sulfur dioxide. Concentrations of sulfur compounds emitted from composting showed exponentially negative relationship at 1% statistically with the oxygen concentration. It was estimated that hydrogen sulfide and methylmercaptan suddenly increased in the level of 5% oxygen concentration and below, that they were little emitted in 15% and over but sulfur dioxide was emitted in the level of 20% oxygen.

• Journal of Animal Science and Technology
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• v.48 no.2
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• pp.293-306
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• 2006

We characterized physicochemical properties and examined the organoleptic and textural evaluations of Feta cheese made from goat's milk. Nutritional compositions of goat Feta cheese were fat 23.50%, protein 11.03% with moisture content of 59.54%. Cell numbers of lactic starter cultures in Feta cheese maintained from log 8.46 CFU/g and pH 5.76 during storage at 4℃ for 14 day's aging. The color of Feta cheese was whitish (L. 93.19) at after finishing brine salting, but became a little yellowish(b. 3.52) (a. -0.71). For texture profile analysis of goat Feta cheese, hardness, fracturability springness, and cohesiveness seemed to be week, but adhesiveness gumminess, chewiness, and resilience were enhanced as aging times extended to 14days, resulted in the overall textural properties was to be superior to control cheese(commercial Mozzarella cheese). Organoleptic evaluations were examined based on the intensities and the preferences for flavour, tastes, texture and mouth feeling. saltiness, bitterness and acidity were stronger in the intensities than control cheese, but the preferences were enhanced by aging to be better than control cheese at 14 days and later on, however, the texture changed to be weaker in hardness and unpleasant in mouthfeel. The fatty acid compositions of Feta cheese analysed by Gas chromatography were saturated fatty acid 42.06%, monoenoic acids 29.67%, di-enoic acids 24.24%, tri-enoic acids 1.21%.

• Korean Journal of Environmental Agriculture
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• v.31 no.2
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• pp.157-163
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• 2012

BACKGROUND: For the safety of imported agricultural products, the study was conducted to develop the analytical method of unregistered pesticides in domestic. The analytical method of 6 pesticides, chlorthal-dimethyl, clomeprop, diflufenican, hexachlorobenzene, picolinafen, and propyzamide, for a fast multi-residue analysis were established for two different type crops, orange and brown rice by GC-ECD and confirmed by mass spectrometry. METHODS AND RESULTS: The analytical method was evaluated to limit of quantification, linearity and recoveries. The crop samples were extracted with acetonitrile and performed cleanup by liquid-liquid partition and Florisil SPE to remove co-extracted matrix. The extracted samples were analyzed by GC-ECD with good sensitivity and selectivity of the method. The limits of quantification (LOQ) range of the method with S/N ratio of 10 was 0.02~0.05 mg/kg for orange and brown rice. The linearity for targeted pesticides were $R^2$ >0.999 at the levels ranged from 0.05 to 10.0 mg/kg. The average recoveries ranged from 74.4% to 110.3% with the percentage of coefficient variation in the range 0.2~8.8% at two different spiking levels (0.02 mg/kg and 0.2 mg/kg, 0.05 mg/kg and 0.5 mg/kg) in brown rice. And the average recoveries ranged from 77.8% to 118.4% with the percentage of coefficient variation in the range 0.2~6.6% at two different spiking levels (0.02 mg/kg and 0.2 mg/kg, 0.05 mg/kg and 0.5 mg/kg) in orange. Final determination was by gas chromatography/mass spectrometry/selected ion monitoring (GC/MS/SIM) to identify the targeted pesticides. CONCLUSION: As a result, this developed analytical method can be used as an official method for imported agricultural products.

• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.381-388
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• 2017

In this study, we investigated the levels of natural preservatives of benzoic acid, sorbic acid, and propionic acid in spices. The quantitative analysis was performed using high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) for benzoic acid and sorbic acid and gas chromatography-mass spectrometry (GC-MS) for propionic acid. The sample was extracted with ethanol using sonication, then centrifuged and evaporated to dryness and redissolved to 1 mL with ethanol to use for the instrumental analysis. The analytical method was validated based on linearity, recovery, limit of detection (LOD), and limit of quantification (LOQ). This method was suitable to determine low amounts of naturally occurring preservatives (benzoic acid, sorbic acid, and propionic acid) in various spices. Benzoic acid, sorbic acid, and propionic acid were found in 165 samples, 88 samples, and 398 samples, respectively from the total of 493 samples. The concentration of benzoic acid, sorbic acid, and propionic acid were ranged at ND-391.99 mg/L, ND-57.70 mg/L, and ND-188.21 mg/L in spices, respectively. The highest mean levels of benzoic acid, sorbic acid, and propionic acid were found in cinnamon (167.15 mg/L), basil leaves (22.79 mg/L), and white pepper (51.48 mg/L), respectively. The results in this study provide ranges of concentration regarding naturally occurring benzoic acid, sorbic acid, and propionic acid in spices. Moreover, the results may use to the case of consumer complaint or trade friction due to the inspection services of standard criteria for the preservatives of spices.

• Economic and Environmental Geology
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• v.25 no.3
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• pp.259-273
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• 1992

The Seongsan mine is one of the largest dickite deposits in the southwestern part of the Korean Peninsula. The main constithent minerals of the ore are dickite and quartz with accessory alunite, kaolinite and sericite. The geology around the Seongsan mine consists mainly of the late Cretaceous felsic volcanic rocks. In the studied area, these rocks make a synclinal structure with an axis of E-W direction plunging to the east. Most of the felsic volcanic rocks have undergone extensive hydrothermal alteration. The hydrothermally altered rocks can be classified into the following zones: Dickite, Dickite-Quartz, Quartz, Sericite, Albite and Chlorite zones, from the center to the margin of the alteration mass. Such zonal arrangement of altered rocks suggests that the country rocks, most of which are upper part of the rhyolite and welded tuff, were altered by strongly acid hydrothermal solutions. It is reasonable to consider that initial gas and solution containing $H_2S$ and other compounds were oxidized near the surface, and formed hydrothermal sulfuric acid solutions. The mineralogical and chemical changes of the altered rocks were investigated using various methods, and chemical composition of fifty-six samples of the altered rocks were obtained by wet chemical analysis and X.R.F. methods. On the basis of these analyses, it was found that some components such as $SiO_2$, $Al_2O_3$, $Fe_2O_3$, CaO, MgO, $K_2O$, $Na_2O$ and $TiO_2$ were mobilized considerably from the original rocks. The formation temperature of the deposits was estimated as higher than $200^{\circ}C$ from fluid inclusion study of samples taken from the Quartz zone. On the basis of the chemical composition data on rocks and minerals and estimated temperatures, the hydrothermal solutions responsible for the formation of the Seongsan dickite deposits were estimated to have the composition: $m_{K^+}=0.003$, $m_{Na^+}=0.097$, $m_{SiO_2(aq.)}=0.008$ and pH=5.0, here "m" represents the molality (mole/kg $H_2O$).

• Journal of Food Hygiene and Safety
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• v.33 no.5
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• pp.375-382
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• 2018

This study was conducted to analyze the microbial community and propionic acid production ability of natural microflora in the rice cakes. Genetic analysis of natural microflora in Jorangyi rice cake was performed to select propionic acid - producing bacteria. Selected propionic acid-producing bacteria were cultivated in TSB (tryptic soy broth) supplemented with glucose, and growth characteristics were analyzed by temperature and production of propionic acid was analyzed by gas chromatography (GC-FID). Linearity, detection limit, quantitative limit, and recovery rate were measured to verify propionic acid assay. A total of 98 microbial strains were detected from microflora of Joraengyi rice cake that grew after expiration of shelf life. Lactobacillus casei group accounted for 50.48% and Lactobacillus buchneri was 29.60%. Propionic acid - producing bacteria were Propionibacterium thoenii, P. cyclohexanicum, Propionibacterium_uc, P. jensenii, and P. freudenreichii. Natural bacteria and Lactobacillus spp. did not produce propionic acid during 14 days but P. cyclohexanicum, P. freudenreichii subsp. Shermanii, P. thoenii and P. jesenii produced $263.47{\mu}g/mL$, $338.90{\mu}g/mL$, $325.43{\mu}g/mL$ and $222.17{\mu}g/mL$ during 4 days and 2,462.02 and 2,904.78, 2,220.64, $3,519.17{\mu}g/mL$ during 14 days. As a result of this study, it was affirmed that the natural microflora of Joraengyi rice cake during storage can produce propionic acid from natural sources even if a high concentration of propionic acid is not intentionally added. Because of characteristics of rice cake composed of starch and glucose. This study will be used as a recognition criterion to detect natural preservatives such as propionic acid in starchy foods such as rice cakes and as reference standard safety management data.

• Tuberculosis and Respiratory Diseases
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• v.46 no.4
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• pp.500-511
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• 1999

Background: Noninvasive positive pressure ventilation (NPPV) using facial or nasal mask have been widely used for several years in stable patients with chronic neuromuscular disease or central alveolar hypoventilation, and recently have been tried in patients with acute respiratory failure. In a few studies, NPPV was also used to rescue the patients with post-extubation respiratory failure. However, yet it has not been adopted as a weaning method in patients on long-term mechanical ventilation. So we performed this prospective clinical study to evaluate the usefulness of NPPV as a weaning method after removing endotracheal tube intentionally in patients on long-term mechanical ventilation. Method: Twelve patients who had been on invasive mechanical ventilation over 10 days were enrolled and 14 trials of NPPV were done. All had failed at least one weaning trial and showed ventilator dependence(pressure support requirement between 8-15cm $H_2O$, and PEEP requirement between 5-10cm $H_2O$), so tracheostomy was being considered. After removing the endotracheal tube, NPPV was applied using facial mask. Respiratory rate, arterial blood gas, pressure support level, and PEEP level were monitored just before intended extubation, at 30 minutes, 1 to 6, 6 to 12, 12 to 24 hours, 2nd day, and 3rd day following initiation of NPPV, and just before weaning from NPPV. The successful weaning was defined as spontaneous breathing off the ventilator for 48 hours or longer without respiratory distress. Results: The weaning through NPPV after intended extubation was successful in 7(50%) of 14 trials, and tracheostomy could be avoided in them. There were no differences in age, sex, APACHE III score, duration of invasive mechanical ventilation, baseline respiratory rate, $PaCO_2$ $PaO_2/FiO_2$, and ventilatory requirement(PS and PEEP) between the success and failure groups. In the success group, respiratory rate, pH, $PaCO_2$, and $PaO_2/FiO_2$ were not different between invasive MV and NPPV period. But in the failure group, pH decreased after 30 minutes of NPPV initiation compared with that of invasive MV($7.40\pm0.08$ vs. $7.34\pm0.06$, p<0.05). The causes of failure were worsening of ABG(n=3), retained tracheal secretion(n=2), mask intolerance(n=1), and flail chest(n=1). Conclusion: NPPV may be worth trying as a bridge method in weaning patients on long-term invasive mechanical ventilation.

• Tuberculosis and Respiratory Diseases
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• v.46 no.6
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• pp.846-855
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• 1999

Background : Secondary pulmonary hypertension is an important final endpoint in patients with chronic hypoxic lung disease, accompanied by deterioration of pulmonary hemodynamics. The clinical diagnosis of pulmonary hypertension and/or cor pulmonale could be difficult, and simple noninvasive evaluation of pulmonary artery pressures has been an relevant clinical challenge for many years. Doppler echocardiography might to be a more reliable method for evaluating pulmonary hemodynamics in such patients in terms of the accuracy, reproducibility and easiness for obtaining an appropriate echocardiographic window than M-mode echocardiography. The aim of this study was to assess echocardiographic parameters associated with pulmonary arterial hypertension, defined by increasing right ventricular systolic pressure(RVSP), calculated from trans-tricuspid gradient in patients with chronic hypoxic lungs. Method : We examined 19 patients with chronic hypoxic lung disease, suspected pulmonary hypertension under the clinical guidelines by two dimensional echocardiography via the left parasternal and subcostal approach in a supine position. Doppler echocardiography measured RVSP from tricuspid regurgitant velocity in continuous wave with 2.5MHz transducer and acceleration time(AT) on right ventricular outflow tract in pulsed wave for the estimation of pulmonary arterial pressure. Results : On echocardiography, moderate to severe degree of pulmonary arterial hypertension was defined as RVSP more than 40mmHg, presenting tricuspid regurgitation. Increased right ventricular endsystolic diameter and shortened AT were noted in the increased RVSP group. Increased RVSP was correlated negatively with the shortening of AT. Other clinical data, including pulmonary functional parameters, arterial blood gas analysis and M mode echocardiographic parameters were not changed significantly with the increased RVSP. Conclusion : These findings suggest that shortened AT on pulsed doppler can be useful when quantifying pulmonary arterial pressure with increased RVSP in patients with chronic lung disease with hypoxemia. Doppler echocardiography in pulmonary hypertension of chronic hypoxic lungs is an useful option, based on noninvasiveness under routine clinical practice.

• Management & Information Systems Review
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• v.37 no.3
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• pp.27-47
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• 2018

In this study, we examine how land use zoning affects the land price controlling other variables such as road-facing condition of the land, land form, land age after its development and land size. We employ geographically weighted regression analysis which reflects spatial dependency as methodology with a data sample of land transaction price data of Jangyu, a new town, in Korea. The results of our empirical analysis show that the respective coefficients of traditional regression and geographically weighted regression are not significantly different. However, after calculating Moran's Index with residuals of both OLS and GWR models, we find that Moran's Index of GWR decreases around 26% compared to that of OLS model, thus improving the problem of spatial autoregression of residuals considerably. Unlike our expectation, though, in both traditional regression and geographically weighted regression where residential exclusive area is used as a reference variable, the dummy variable of the residential land for both housing and shops shows a negative sign. This may be because the residential land for both housing and shops is usually located in the level area while the residential exclusive area is located at the foot of a mountain or on a gentle hill where the residents can have good quality air and scenery. Although the utility of the residential land for both housing and shops is higher than its counterpart's since it has higher floor area ratio, amenity which can be explained as high quality of air and scenery in this study seems to have higher impact in purchase of land for housing. On the other hand, land for neighbourhood living facility seems to be valued higher than any other land zonings used in this research since it has much higher floor area ratio than the two land zonings above and can have a building with up to 5 stories constructed on it. With regard to road-facing condition, land buyers seem to prefer land which faces a medium-width road as expected. Land facing a wide-width road may have some disadvantage in that it can be exposed to noise and exhaust gas from cars and that entrance may not be easy due to the high speed traffic of the road. In contrast, land facing a narrow road can be free of noise or fume from cars and have privacy protected while it has some inconvenience in that entrance may be blocked by cars parked in both sides of the narrow road. Finally, land age variable shows a negative sign, which means that the price of land declines over time. This may be because decline of the land price of Jangyu was bigger than that of other regions in Gimhae where Jangyu, a new town, also belong, during the global financial crisis of 2008.