• Food Science and Preservation
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• v.6 no.4
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• pp.351-356
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• 1999

To develop and extend the shelf-life of vitamin C enriched fresh-cut apples using CA stored Fuji apples, dipping in 10% L-ascorbic acid and packaging with 0.03 mm LDPE, 0.04 mm PP and 0.08 mm Nylon/PE film(N$_2$displacement) were carried out. The changes of gas concentrations in the packaging and quality attributes of fresh-cut apples were examined during storage at 10$^{\circ}C$. The concentrations of O$_2$was maintained lower in Nylon/PE film than the other film, the level of O$_2$was in the range of 1∼3%. The increase of C$_2$H$_4$ concentrations in Nylon/PE film bag was more suppressed than the others. The vitamin C content of fresh-cut apples was enriched by dipping in L-ascorbic acid solution up to 241 mg$.$100 g-1 f.w., and the loss or that content was retarded differently by the package conditions of lower O$_2$level during storage. Browning in fresh-cut apples was shown after 6 days of storage in LDPE and PP film. but it was not shown by 14 days of storage in Nylon/PE film. Spoilage and off odor in fresh-cut apples were not detected up to 14 days of storage in Nylon/PE film. The results indicated that the vitamin C enriched fresh-cut apples can be processed from the long-term CA stored apples, and maintaining high quality of the products ill be possible in cases of the application of sealing packaging after O$_2$removal with film having low O$_2$permeability.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.634-639
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• 2021

This study investigated the effects of cold plasma (CP) treatment on the properties of biopolymer films prepared with defatted mustard meal (DMM films). CP treatments using N₂, O₂, He, Ar, and dry air did not affect the tensile properties, water vapor permeability, color, and morphology of DMM films, whereas the treatments using He and Ar improved their printability. The tensile strength (TS) of O₂- or air-CP-treated DMM films and the elastic modulus (EM) of O₂-, He-, Ar-, or air-CP-treated films were lower than those of the untreated films. An increase in the power of Ar-CP treatment resulted in an increase in EM. The optimum treatment power and time for minimizing yellowness changes by Ar-CP treatment were 420 W and 40 min, respectively. The results demonstrated the potential application of CP treatment to improve the film properties of DMM films and possibly other agricultural by-product-based biopolymer films, making the films more applicable to food packaging.

• Korean Journal of Ichthyology
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• v.30 no.4
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• pp.232-237
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• 2018

The feeding habits of Beringraja pulchra were studied using 203 specimens collected from February 2017 to March 2018 in the coastal waters of Incheon, Korea. The size of B. pulchra ranged from 31.1 to 77.7 cm in disc width (DW) and the stomachs of 16 specimens were empty. B. pulchra was a carnivore that mainly consumed fishes and shrimps, but also ate various benthic crustaceans and other invertebrates with small amounts. The main prey items in the diets of shrimps and fishes were Crangon hakodatei and Ammodytes personatus, respectively. The proportion of fishes in prey items increased with size-related while that of shrimps decreased. With increasing disc width of B. pulchra, the mean number of preys per stomach (mN/ST) and the mean weight of preys per stomach (mW/ST) were increased.

• Geomechanics and Engineering
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• v.17 no.4
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• pp.333-342
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• 2019

Geological dynamic hazards during coal mining can be caused by the failure of a composite system consisting of roof rock and coal layers, subject to different loading rates due to different advancing velocities in the working face. In this paper, the uniaxial compression test simulations on the composite rock-coal layers were performed using $PFC^{2D}$ software and especially the effects of loading rate on the stress-strain behavior, strength characteristics and crack nucleation, propagation and coalescence in a composite layer were analyzed. In addition, considering the composite layer, the mechanisms for the advanced bore decompression in coal to prevent the geological dynamic hazards at a rapid advancing velocity of working face were explored. The uniaxial compressive strength and peak strain are found to increase with the increase of loading rate. After post-peak point, the stress-strain curve shows a steep stepped drop at a low loading rate, while the stress-strain curve exhibits a slowly progressive decrease at a high loading rate. The cracking mainly occurs within coal, and no apparent cracking is observed for rock. While at a high loading rate, the rock near the bedding plane is damaged by rapid crack propagation in coal. The cracking pattern is not a single shear zone, but exhibits as two simultaneously propagating shear zones in a "X" shape. Following this, the coal breaks into many pieces and the fragment size and number increase with loading rate. Whereas a low loading rate promotes the development of tensile crack, the failure pattern shows a V-shaped hybrid shear and tensile failure. The shear failure becomes dominant with an increasing loading rate. Meanwhile, with the increase of loading rate, the width of the main shear failure zone increases. Moreover, the advanced bore decompression changes the physical property and energy accumulation conditions of the composite layer, which increases the strain energy dissipation, and the occurrence possibility of geological dynamic hazards is reduced at a rapid advancing velocity of working face.

• Journal of Animal Science and Technology
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• v.61 no.5
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• pp.260-271
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• 2019

The objective of this study was to determine the effect of different stocker management programs on skeletal muscle development and growth characteristics, satellite cell (SC) activity in growing-finishing beef cattle as well as the effects of SC-conditioned media on preadipocyte gene expression and differentiation. Fall-weaned Angus steers (n = 76; $258{\pm}28kg$) were randomly assigned to 1 of 4 stocker production systems: 1) grazing dormant native range (NR) supplemented with a 40% CP cottonseed meal-based supplement ($1.02kg{\cdot}steer^{-1}{\cdot}d^{-1}$) followed by long-season summer grazing (CON, 0.46 kg/d); 2) grazing dormant NR supplemented with a ground corn and soybean meal-based supplement fed at 1% of BW followed by short-season summer grazing (CORN, 0.61 kg/d); 3) grazing winter wheat pasture (WP) at high stocking density (3.21 steers/ha) to achieve a moderate rate of gain (LGWP, 0.83 kg/d); and 4) grazing winter WP at low stocking density (0.99 steers/ha) to achieve a high rate of gain (HGWP, 1.29 kg/d). At the end of the stocker (intermediate harvest, IH) and finishing (final harvest, FH) phases, 4 steers / treatment were harvested and longissimus muscles (LM) sampled for cryohistological immunofluorescence analysis and SC culture assays. At IH, WP steers had greater LM fiber cross-sectional area than NR steers; however, at FH, the opposite was observed (p < 0.0001). At IH, CORN steers had the lowest Myf-5+:Pax7+ SC density (p = 0.020), while LGWP steers had the most Pax7+ SC (p = 0.043). At FH, CON steers had the highest LM capillary density (p = 0.003) and their cultured SC differentiated more readily than all other treatments (p = 0.017). At FH, Pax7 mRNA was more abundant in 14 d-old SC cultures from HGWP cattle (p = 0.03). Preadipocytes exposed to culture media from proliferating SC cultures from WP cattle isolated at FH had more $PPAR{\gamma}$ (p = 0.037) and less FABP4 (p = 0.030) mRNA expression compared with NR cattle. These data suggest that different stocker management strategies can impact skeletal muscle growth, SC function, and potentially impact marbling development in growing-finishing beef cattle.

• Geophysics and Geophysical Exploration
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• v.22 no.3
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• pp.107-115
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• 2019

Recently, since earthquakes have happened frequently in Gyeongju and Pohang areas in Korea, the earthquake detection research gets lots of attention. Geophysical monitoring data have been changed during the earthquake activity because the huge amount of energy is accumulated. The change of telluric current can be predicted by both of piezoelectric and electrokinetic effects before or during the earthquake occurrence, and if the change value exceeds the conventional telluric current noise, we can measure changes in the electric field associated with earthquakes. In this study, we have self-developed and verified the system that can monitor the telluric current. In order to verify our telluric current monitoring system, we installed lines of 40 m (E-W direction) and 28 m (N-S direction) on the site in Pohang. The telluric currents were sampled at 1 kHz for about a month. We have compared and analyzed the data of earthquake signals and electrical noises based on the earthquakes that occurred during the monitoring period. We have monitored if there were significant signals related to the earthquake on measured time series data. Through this study, we will suggest the direction of continuous research in the future.

• The Journal of the Korean dental association
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• v.57 no.10
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• pp.560-568
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• 2019

Purpose: This study evaluated the antibacterial effects of curcuma, ginger, and finger root extracts in water-soluble powder on planktonic Streptococcus mutans(S.mutans), which is known to cause dental caries, in order to confirm whether these extracts could perform as photosensitizers for the effects of photodynamic therapy (PDT). Methods: This study used the strain of streptococcus mutans ATCC 25175 distributed by the Korean Collection for Type Cultures of the Korea Research Institute of Bioscience & Biotechnology. Commercial edible curcuma, ginger and finger root were used as the natural extracts for the use of photosensitizer. To extract organic solvent, 3 g of each powder was mixed in $30m{\ell}$ of dimethyl sulfoxide (DMSO, VWR, Germany) before extraction. $1.8m{\ell}$ of the photosensitizer solution, manufactured in the concentrations of 5, 0.5, and $0.05mg/m{\ell}$, was mixed with $0.2m{\ell}$ of the S. mutans culture medium that had been cultured for 2 days. To induce the photodynamic reaction, Qraycam (AIOBIO, Seoul, Korea) equipped with 405 nm LED was used to expose light for 5 minutes to irradiate 59 nW energy for 300 seconds. Results: Compared with the case with no light, a higher photodynamic therapeutic effect was confirmed with $0.05mg/m{\ell}$ curcuma powder extract, the concentration of $0.5mg/m{\ell}$ and LED light of 405 nm wavelength (p=0.000, p=0.003). $0.05mg/m{\ell}$ of curcuma powder extract and the concentration of $0.5mg/m{\ell}$ showed 100% antibacterial effect when exposed to light, whereas the concentration of $5mg/m{\ell}$ showed 11.95% antibacterial effect. When exposed to light, $0.05mg/m{\ell}$ of ginger powder extract showed an antibacterial effect which didn't statistically decrease. The concentrations of $0.5mg/m{\ell}$ and $5mg/m{\ell}$ did not show any antibacterial effects. As a result of examining any photodynamic therapeutic effects of finger root powder extract on S. mutans, no statistically significant effect was found. Conclusion: The curcuma powder extract is expected to perform as a photosensitizer. Even though belonging to the same ginger family, ginger powder and finger root powder seem difficult to perform as photosensitizer.

• Korean Journal of Plant Resources
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• v.32 no.4
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• pp.379-406
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• 2019

A floristic study on the vascular plants from Juwangsan National Park was conducted 13 times in total, from March to October 2017. Based on the voucher specimens and pictures, it was revealed that the vascular plants in this region comprised 758 taxa: 112 families, 399 genera, 672 species, 4 subspecies, 72 varieties, and 10 forma. Among these plants, 221 taxa were recorded for the first time from this region. The taxa in category II of endangered plants designated by the Korean Ministry of Environment were two taxa, including Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. and Epilobium hirsutum L. The rare plants numbered 5 taxa designated by National Institute of Biological Resources were also found. 20 taxa of Korean endemic plants including Corydalis alata B.U.Oh & W.R.Lee, Iris odaesanensis Y.N.Lee, and Scrophularia cephalantha Nakai were investigated in this region. 40 taxa of floristic regional indicator plants in the 3rd to the 5th degrees were identified. Naturalized plants of 55 taxa were recorded, and 3 taxa of ecosystem disturbance plants, which were Ambrosia artemisiifolia L., Aster pilosus Willd., and Lactuca scariola L., also found.

• Animal Bioscience
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• v.34 no.1
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• pp.2-11
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• 2021

Objective: The aim of the study was to evaluate the influence of polymorphic loci and other factors on milk performance and the technological properties of milk. Methods: The analysis was performed on Simmental and Holstein cows in field conditions (n = 748). Milk yield in kg, fat and protein percentage and yield were evaluated. Technological properties were evaluated by milk fermentation ability, renneting, and an alcohol test. Polymorphisms in the acyl-CoA diacylgycerol transferase 1 (DGAT1), leptin (LEP), fatty acid synthase (FASN), stearoyl CoA desaturase 1 (SCD1), casein beta (CSN2), casein kappa (CSN3), and lactoglobulin beta genes were genotyped, and association analysis was performed. Results: The DGAT1 AA genotype was associated with higher milk, protein and fat yields (p<0.05). The MM genotype in the LEP gene was associated with a lower protein percentage and the W allele with a higher protein percentage (p<0.05). In cows with the FASN GG genotype, the protein percentage was higher, but the A allele was associated with higher milk, protein and fat yields than the G allele. The TT genotype in SCD1 was associated with the lowest milk, protein and fat yields and with the highest milk protein percentage (p<0.01). The T allele had higher values than the C allele (p<0.05) except for fat percentage. The genotype CSN3 AA was associated with a significantly heightened milk yield; BB was associated with a high protein percentage. The effect of the alleles on the technological properties was not significant. The CSN2 BB genotype was associated with the best alcohol test (p<0.01), and the renneting order was inverse. Milk from cows with the CSN2 A1A1 genotype was best in the milk fermentation ability. CSN3 significantly affected the technological properties. Conclusion: The findings revealed the potential of some polymorphic loci for use in dairy cattle breeding and for the management of milk quality. In field research, the pivotal role of farms in milk yield, composition and technological properties was confirmed.

• Journal of The Korean Astronomical Society
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• v.55 no.5
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• pp.173-194
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• 2022

We complete the survey for finite-source/point-lens (FSPL) giant-source events in 2016-2019 KMTNet microlensing data. The 30 FSPL events show a clear gap in Einstein radius, 9 𝜇as < 𝜃_E < 26 𝜇as, which is consistent with the gap in Einstein timescales near t_E ~ 0.5 days found by Mróz et al. (2017) in an independent sample of point-source/point-lens (PSPL) events. We demonstrate that the two surveys are consistent. We estimate that the 4 events below this gap are due to a power-law distribution of free-floating planet candidates (FFPs) dN_FFP/d log M = (0.4 ± 0.2) (M/38 M_⊕)^-p/star, with 0.9 ≲ p ≲ 1.2. There are substantially more FFPs than known bound planets, implying that the bound planet power-law index 𝛾 = 0.6 is likely shaped by the ejection process at least as much as by formation. The mass density per decade of FFPs in the Solar neighborhood is of the same order as that of 'Oumuamua-like objects. In particular, if we assume that 'Oumuamua is part of the same process that ejected the FFPs to very wide or unbound orbits, the power-law index is p = 0.89 ± 0.06. If the Solar System's endowment of Neptune-mass objects in Neptune-like orbits is typical, which is consistent with the results of Poleski et al. (2021), then these could account for a substantial fraction of the FFPs in the Neptune-mass range.