• Journal of Food Hygiene and Safety
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• v.37 no.3
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• pp.143-148
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• 2022

This study was to investigate an analytical method for determining dieckol content in Ecklonia stolonifera extract. According to the guidelines of International Conference on Harmonization. Method validation was performed by measuring the specificity, linearity, precision, accuracy, limit of detection (LOD), and limit of quantification (LOQ) of dieckol using high-performance liquid chromatography-photodiode array. The results showed that the correlation coefficient of calibration curve (R²) for dieckol was 0.9997. The LOD and LOQ for dieckol were 0.18 and 0.56 ㎍/mL, respectively. The intra- and inter-day precision values of dieckol were approximately 1.58-4.39% and 1.37-4.64%, respectively. Moreover, intra- and inter-day accuracies of dieckol were approximately 96.91-102.33% and 98.41-105.71%, respectively. Thus, we successfully validated the analytical method for estimating dieckol content in E. stolonifera extract.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.398-403
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• 2023

Process-based K-cabbage model is based on physiological processes such as photosynthesis and phenology, making it possible to predict crop growth under different climate conditions that have never been experienced before. Current first-stage process-based models can be used to assess climate impact through yield prediction based on climate change scenarios, but no comparison has been performed between big data obtained from the main production area and model prediction so far. The aim of this study was to find out the direction of model improvement when using the current model for yield prediction. For this purpose, model performance evaluation was conducted based on data collected from farmers growing 'Chungwang' cabbage in Taebaek and Samcheok, the main producing areas of Chinese cabbage in highland region. The farms surveyed in this study had different cultivation methods in terms of planting date and soil water and nutrient management. The results showed that the potential biomass estimated using the K-cabbage model exceeded the observed values in all cases. Although predictions and observations at the time of harvest did not show a complete positive correlation due to limitations caused by the use of fresh weight in the model evaluation process (R²=0.74, RMSE=866.4), when fitting the model based on the values 2 weeks before harvest, the growth suitability index was different for each farm. These results are suggested to be due to differences in soil properties and management practices between farms. Therefore, to predict attainable yields taking into account differences in soil and management practices between farms, it is necessary to integrate dynamic soil nutrient and moisture modules into crop models, rather than using arbitrary growth suitability indices in current K-cabbage model.

• Journal of Food Hygiene and Safety
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• v.39 no.2
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• pp.61-71
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• 2024

In this study, we analyzed chlorogenic acid indicator components in preparation for the additional listing of green coffee bean extract in the Health Functional Food Code and optimized caffeine for simultaneous analysis. We extracted chlorogenic acid and caffeine using 30% methanol, phosphoric acid solution, and acetonitrile-containing phosphoric acid and analyzed them at 330 and 280 nm, respectively, using liquid chromatography. Our analysis validation results yielded a correlation coefficient (R²) revealing a significance level of at least 0.999 within the linear quantitative range. The chlorogenic acid and caffeine detection and quantification limits were 0.5 and 0.2 ㎍/mL and 1.4, and 0.4 ㎍/mL, respectively. We confirmed that the precision and accuracy results were suitable using the AOAC validation guidelines. Finally, we developed a simultaneous chlorogenic acid and caffeine analysis approach. In addition, we confirmed that our analysis approach could simultaneously quantify chlorogenic acid and caffeine by examining the applicability of each formulation through prototypes and distribution products. In conclusion, the results of this study demonstrated that the standardized analysis would expectably increase chlorogenic acidcontaining health functional food quality control reliability.

• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.805-809
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• 2006

Ozonized olive oil was tested for its mutagenic potential in a Salmonella/microsome assay. Additionally, antimicrobial activity was tested against Propionibacterium acnes, Staphylococcus epidermidis, Staphylococcus aureus and Pseudomonas aeruginosa, pathogenic strains related to acne, using the paper disk and agar dilution method. Ozonized olive oil showed antimicrobial activities against all the strains tested, with minimal inhibitory concentrations (MICs) values in a range of 2${\sim}$10 mg/mL. Mutagenicity of ozonized olive oil was evaluated with Salmonells typhimurium TA98, TA100 and Ta1535, with and without addition of S9 mixture. No increase in the number of $his^{+}$ revertants over the negative control (solvent and non-ozonized olive oil) values was observed with TA98 (1,000 ${\mu}g/plate$), TA100 (1,500 ${\mu}g/plate$) and TA1535 (1,500 ${\mu}g/plate$) strains. The results from this study suggested that ozonized olive oil does not show any mutagenic potential.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.381-392
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• 2002

This study attempted to indentify changeability of the factorial structure of kinematic analysis in bowling. Subjects of group composed of three groups : Higher bowers who are national representative bowers with 200 average point and one pro-bowler. Middle bowlers who are three common persons with 170 average points. Lower bowler who are three common persons with 150 average points. Motion analysis on throw motion in three groups respectively has been made through three-dimension cinematography using DLT method. Two high-speed video camera at operating 180 and 60 frame per secondary. T-test factorial structure analysis has been used to define variable relations. It was concluded that : 1. The difference of x1, x2, x4, x8, x9, x11, x12, x13 where significant between two group. 2. The difference of number of spin and angle of the back-hand where statistically significant between two group(p<.001, p<.05) 3. The correlation over r=.5 between the kinematic data x1, x2, x3, x9, x10, x11. In the rotation loading matrix Factor 1 was x1, x2, x9, x10 and Factor 2 relates to x3, x11. 4. In order to obtain the factor score as follow as ; Factor 1 = (0.248)X1 + (0.265)X2 + (-0.074)X3 + (0.259)X9 + (0.259)X10 + (-0.025)X11 Factor 2=(-0.016)X1 + (-0.055)X2 + (0.84)X3 + (-0.013)X9 + (-0.007)X10 + (0.553)X11.

• Parasites, Hosts and Diseases
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• v.55 no.2
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• pp.207-212
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• 2017

Infections of Toxoplasma gondii and Babesia microti are reported in many wild animals worldwide, but information on their incidence and molecular detection in Korean wild fields is limited. In this study, the prevalence of T. gondii and B. microti infection in blood samples of 5 animal species (37 Chinese water deer, 23 raccoon dogs, 6 roe deer, 1 wild boar, and 3 Eurasian badgers) was examined during 2008-2009 in Gangwon-do (Province), the Republic of Korea (=Korea) by using serological and molecular tests. The overall seropositivity of T. gondii was 8.6% (6/70); 10.8% in Chinese water deer, 4.3% in raccoon dogs, and 16.7% in roe deer. PCR revealed only 1 case of T. gondii infection in Chinese water deer, and phylogenic analysis showed that the positive isolate was practically identical to the highly pathogenetic strain type I. In B. microti PCR, the positive rate was 5.7% (4/70), including 2 Chinese water deer and 2 Eurasian badgers. Phylogenetic analysis results of 18S rRNA and the ${\beta}$-tubulin gene showed that all positive isolates were US-type B. microti. To our knowledge, this is the first report of B. microti detected in Chinese water deer and Eurasian badger from Korea. These results indicate a potentially high prevalence of T. gondii and B. microti in wild animals of Gangwon-do, Korea. Furthermore, Chinese water deer might act as a reservoir for parasite infections of domestic animals.

• Korean Journal of Food Science and Technology
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• v.41 no.5
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• pp.587-591
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• 2009

Volatiles in Artemisia princeps Pampan. cv. sajabal (sajabalssuk) and A. princeps Pampan. (ssuk) treated with different processing were analyzed using headspace-solid phase microextraction (HS-SPME)/gas chromatography- a mass selective detector (GC-MS). Sajabalssuk and ssuk were treated with steam distillation (SD) and freeze-dried/steam distillation (FD/SD) while controls were raw sajabalssuk and raw ssuk. Sajabalssuk had significantly more total volatiles than ssuk in control and FD/SD treated samples (p<0.05). Major volatiles in raw sajabalssuk were 2-hexenal, 1,8-cineol, trans-caryophyllene, and hexanal while those in raw ssuk were 1-hexanol, ${\beta}$-myrcene, limonene, and 2-hexenal, which implies that substantial lipid oxidation occurred in raw samples. Sajabalssuk with SD and FD/SD treatment had higher peak areas of 1,8-cineole, 4-terpineol, 1-octen-3-ol, and ${\alpha}$-terpineol while ssuk with SD and FD/SD treatment possessed 1,8-cineol, camphor, borneol, artemisia ketone, ${\alpha}$-thujone, and 1-octen-3-ol, which showed that steam distillation produced more volatiles from terpenoids than raw samples. Based on the results of HS-SPME/GC-MS, relative amounts of volatiles from lipid oxidation including 2-hexenal, hexanal, and 1-hexanol were reduced in sajabalssuk and ssuk with freeze-drying and/or steam distillation treatment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.2
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• pp.220-227
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• 2016

In this paper, polychlorinated biphenyls (PCBs) were measured in surface sediments collected three times (June, October, December, 2013), inside Jeju Harbor as major harbors of Jeju Island. The concentration of PCBs inside Jeju Harbor was in the range of 1.62~4.45 (mean) ng/g on a dry weight basis and the levels were very low. In the analysis of PCBS homologue patterns, high-chlorinated PCB congeners were dominant in surface sediments inside Jeju Harbor, indicating that their sources were originated from shipping activity. In the relationships between PCBs concentrations and particle size (mud, sand and gravel) in surface sediments, PCBs concentrations were higher in the sediments with higher mud content, indicating that higher PCBs were distributed with increasing sediments of fine gradules. The PCBs concentrations in surface sediments in this study were very low, compared with ER-L (effect range-low) and TEL (threshold effects level) among sediment quality guideleines (SQGs) applied in foreign countries, such as USA, Canada, and Australia, etc), indicating that their biological effects on the bottom organisms in marine environment were expected to be very low.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.1
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• pp.11-14
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• 2012

The AlGaN layer has direct wide bandgaps ranging from 3.4 to 6.2 eV. Nowadays, it is becoming more important to fabricate optical devices in an UV region for the many applications. The high quality AlGaN layer is necessary to establish the UV optical devices. However, the growth of AlGaN layer on GaN layer is difficult due to the lattice mismatch and difference thermal expansion coefficient between GaN layer and AlGaN layer. In this paper, we attempted to grow the LED structure on GaN template by mixed-source HVPE method with multi-sliding boat system. We tried to find the optical and lattice transition of active layer by control the Al content in mixed-source. For the growth of epi layer, the HCl and $NH_3$ gas were flowed over the mixed-source and the carrier gas was $N_2$. The temperature of source zone and growth zone was stabled at 900 and $1090^{\circ}C$, respectively. After the growth, we performed the x-ray diffraction (XRD) and electro luminescence (EL) measurement.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.1
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• pp.72-76
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• 1983

Absorption pattern and sensitivity of radishes to boron were compared with different boron treatment: soil application, foliar spray and no boron application. Six radish cultivars were planted on April 7 and harvested on June 23. Borax 1.5 Kg per 10 a was applied to soil before seeding and the 150 litters of 0.5 ppm solution with bolic acid was sprayed on leaves 3 times during the growing period. Boron content in plant was markedly increased by the soil application but no significant difference in boron contents in plants was observed between foliar spray and no application, presumably because of the insufficient dose of foliar spray. The darkening rot in root, a boron deficiency, was negligible in radishes grown in soil application plots whereas a relatively higher percentage of boron deficient plant was found from foliar spray or no application plots. The appearance of root darkening rot occurred at the rapid root enlargement stage, apparently from 55 days to 65 days after seeding. The boron contents in plants of soil application plots slightly increased at this stage while those of no boron application and foliar spray decreased. This obviously verified that boron deficiency should cause root rots showing highly significant relationship.