• Journal of Marine Bioscience and Biotechnology
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• v.14 no.1
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• pp.1-8
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• 2022

This study examined the growth, fatty acid (FA) content, and carotenoids of a newly isolated freshwater microalga, Mychonastes sp. 246, in various culture media. The appropriate temperature and light intensity for culturing Mychonastes sp. 246 were determined as 18℃-22℃ and 200-250 µmol/m²/s using a high throughput photobioreactor. The microalgal cells were cultivated in 0.5 L bubble column photobioreactors using BG11, Bold's Basal media, and f/2 media. According to the growth results of the microalgae, BG11, among the tested media, showed the highest biomass concentrations (3.5 ± 0.1 g/L in 10 d). To enhance the biomass growth of the microalgae, the N:P ratio in BG11 was manipulated from 45:1 to 7:1 based on the stoichiometric cell composition. The biomass concentrations of Mychonastes sp. 246 grown on the manipulated BG11 (MBG) increased to 38% (4.6 ± 0.3 g/L in d) compared with the original BG11 (3.3 g/L). The FA content of the microalgae grown on the MBG was lower (8.4%) than that of the original BG11 (10.1%) while the FA compositions did not exhibit any significant differences. Furthermore, three kinds of carotenoids were identified in Mychonastes sp. 246, zeaxanthin, lutein, and β-carotene. These results suggest an effective strategy for increasing biomass concentrations, FA content, and carotenoids of microalgae by performing a simple N:P adjustment in the culture media.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.1
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• pp.38-47
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• 1988

To determine the response of soybean cultivars to nitrogen in relation to acidity, nodulation, content of allantoin nitrogen and major chemical compositions of soybean plants were investigated with two cultivars under two levels of soil pH and four levels of nitrogen fertilization in a field and nutri-culture experiments. Nodulation and contents of allantoin nitrogen, total nitrogen, potassium, calcium, magnesium and manganese of soybean plants decreased under acidic condition, but the degree of decrease was smaller in the variety Jangbaegkong compared to the variety Danyeobkong. On the other hand, nodulation, content of allantoin nitrogen and potassium decreased with increased nitrogen fertilization, particulary under pH 7 condition. Nodulation was positively correlated with the content of allantoin nitrogen of soybean plants. The content of total nitrogen of soybean plants increased with increased nitrogen fertilization, and this tendency was remarkable under acidic condition and in the variety Jangbaegkong.

• Journal of Practical Agriculture & Fisheries Research
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• v.7 no.1
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• pp.109-117
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• 2005

This study was carried out to determine effects of the feeding length of spent mushroom composts from selenium-enriched mushroom (Se-SMC) on meat quality and carcass characteristics in finishing Hanwoo steers. A total of 20 steers were used in this trial with four treatments. Treatments included control (no Se-SMC), Se-SMC groups of three different feeding lengths (2, 4, and 6 months). After the completion for each feeding length, steers were slaughtered and then loin muscle (Longissimus dorsi) was sampled to evaluate meat quality characteristics. Chemical compositions of the loin, except for protein content, were not different across treatments. Protein content was highest in 6 months feeding groups, however, it was lowest in 4 months. Physical property and meat color (L*, a* and b* values) were not affected by the feeding length of Se-SMC. However, water holding capacity (WHC) for Se-SMC feeding treatments was significantly more improved (p<0.05) in comparison with the control group, showing 63.8 (2 months), 64.4 (4 months), 64.2 (6 months), and 59.5% (control), respectively. Grades for meat quality and quantity, and carcass characteristics were not affected by feeding length of Se-SMC. Our results showed that Se-SMC supplementation was not significantly associated with parameters for meat quality and carcass characteristics. However, as feeding Se-SMC lengthens, WHC for loin was more improved, suggesting that the improved WC may result in the expression of antioxidant effect.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.675-695
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• 2023

The tracksite of dinosaurs and pterosaurs in Sanbuk-dong of Gunsan is the largest early Cretaceous dinosaur footprint fossil site in Korea, and all the footprints are important evidence indicating that large ornithopod and theropod dinosaurs inhabited the Korean peninsula during the early Cretaceous. The Sanbuk-dong site was covered with waterproof sheet in an outdoor environment until the installation of a protective enclosure in 2021. As a result, various factors such as shear force, load reduction, temperature and humidity fluctuations, acid rain, salinity and microorganisms have complexly interacted in the substrate of fossils, exacerbating the damage to footprints. For 159 footprints in 12 trackways among the footprints found in the site, the damage types were classified in detail and the level of each damage was assessed. The damages were classified into 6 types through the classification of deterioration degree of individual footprints. As a result of ultrasonic physical property evaluation on the surface of the fossil site, most of these footprints are in the completely weathered (CW) stage. Furthermore, various weathering patterns were observed in the study area, and surface contaminants were analyzed along the stratigraphy. Although the patterns of freshness and contaminants varied at different points within the fossil site, the chemical compositions were similar. Based on the results, an efficient conservation management system for dinosaur footprint fossils was established, and a conservation treatment type for each footprint was proposed.

• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.665-669
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• 2023

The crude methylnaphthalene oil (CMNO) contains nitrogen compounds (NCs) such as quinoline (QU), isoquinoline (IQU), and indole (IN). These NCs in the CMNO are treated as impurities contained in the CMNO due to contamination of the atmospheric environment and unpleasant odors. In order to improve the quality of CMNO, this study examined the effect of extraction experimental factors on the reduction of NCs contained in CMNO using CMNO as a raw material and an aqueous formamide solution as a solvent, respectively. The increase in the volume ratio of solvent to feed in initial (S/F)₀ in initial increased the distribution coefficient of NCs and the selectivity of NCs in reference to 2-methylnaphthalene (2MNA). Additionally, an increase in operating temperature (T) increased the distribution coefficient of NCs but conversely decreased selectivity. The compositions of QU, IQU, and IN in the raffinate oil recovered through equilibrium extraction under a constant condition (volume fraction of water to solvent in initial (y_w,0) = 0.1, (S/F)₀ = 9, T = 303 K, liquid-liquid contacting time = 72 h) were reduced by about 58.5 wt%, 61.9 wt%, and 73.4 wt%, respectively, compared to those of CMNO. The formamide extraction method in this study was expected to be an effective reduction method for NCs contained in CMNO.

• Animal Bioscience
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• v.37 no.6
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• pp.1096-1109
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• 2024

Objective: This research aims to explore the nutritional and bioactive peptide properties of goat meat taken from various primal cuts, including the breast, shoulder, rib, loin, and leg, to produce these bioactive peptides during in vitro gastrointestinal (GI) digestion and absorption. Methods: The goat meat from various primal cuts was obtained from Boer goats with an average carcass weight of 30±2 kg. The meat was collected within 3 h after slaughter and was stored at -80℃ until analysis. A comprehensive assessment encompassed various aspects, including the chemical composition, cooking properties, in vitro GI digestion, bioactive characteristics, and the bioavailability of the resulting peptides. Results: The findings indicate that the loin muscles contain the highest protein and essential amino acid composition. When the meats were cooked at 70℃ for 30 min, they exhibited distinct protein compositions and quantities in the sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile, suggesting they served as different protein substrates during GI digestion. Subsequent in vitro simulated GI digestion revealed that the cooked shoulder and loin underwent the most significant hydrolysis during the intestinal phase, resulting in the strongest angiotensin-converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) inhibition. Following in vitro GI peptide absorption using a Caco-2 cell monolayer, the GI peptide derived from the cooked loin demonstrated greater bioavailability and a higher degree of ACE and DPP-IV inhibition than the shoulder peptide. Conclusion: This study highlights the potential of goat meat, particularly cooked loin, as a functional meat source for protein, essential amino acids, and bioactive peptides during GI digestion and absorption. These peptides promise to play a role in preventing and treating metabolic diseases due to their dual inhibitory effects on ACE and DPP-IV.

• Journal of Life Science
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• v.34 no.1
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• pp.68-77
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• 2024

Airborne particulate matter (PM) is an environmentally hazardous pollutant that originates from various sources. PM is comprised of solid particles and liquid droplets of diverse composition and size. Hazardous chemical compositions of PM include elemental and organic carbon, organic compounds, biological compounds and metals. Upon acute and chronic PM exposure, toxic contaminants enter and accumulate within physiological systems and prompt cell structure changes accompanied with intracellular endoplasmic reticulum stress, mitochondrial dysfunction, oxidative stress, inflammation, lipid accumulation, and cell cycle arrest. Ultimately, these cellular response leads to the development of key characteristics of aging. In addition, PM internalization enhances autophagy reflux and lysosomal dysfunction, which is involved in cell aging. Previous studies have emphasized a positive association between PM and increased mortality or decreased lifespan, although these are evidenced mostly by observational studies. Direct evidence of the link between PM and aging is still limited. This review evaluates the evidence from not only observational studies but also in vitro and in vivo evidence of PM on aging progression and age-related diseases development. This evidence is based on age-associated cellular changes including endoplasmic reticulum stress, mitochondrial dysfunction, oxidative stress, inflammation, adipose accumulation, autophagy, which strengthen the association between PM exposure and aging. Understanding the underlying cellular responses under PM may allow for the development of new therapeutic targets for PM-induced aging.

• Korean Journal of Mineralogy and Petrology
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• v.37 no.2
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• pp.13-22
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• 2024

X-ray absorption near-edge structure (XANES) spectroscopy can provide qualitative insights into the coordination chemistry of calcium (Ca) across a variety of geological materials. However, systematic studies on Ca K-edge XANES spectral features and the Ca coordination parameters are rare. This study investigated potential correlations between the spectral features of Ca K-edge XANES and the coordination parameters of Ca for selected Ca-bearing minerals (anorthite, aragonite, calcite, diopside, dolomite, grossular, monohydrocalcite, perovskite, and wollastonite), employing density functional theory (DFT) calculations. DFT calculations accurately reproduced the main features of their experimental Ca K-edge XANES spectra for representative silicates, carbonates, and titanates. No strong correlation was observed between XANES peak positions vs. Ca-O distances (or Ca coordination numbers). However, a significant correlation was noted between the peak intensity of post-edge peaks vs. the effective coordination number of Ca in minerals of similar chemical compositions. These results show the potential, yet limited, applicability of XANES spectra for molecular-level research of Ca-bearing geomaterials, and highlight the critical role of DFT computations in interpretating XANES spectra.

• Applied Biological Chemistry
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• v.14 no.2
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• pp.137-148
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• 1971

Studies were carried out to investigate the main fermentation microorganisms and their flora changes during Korean native soy-sauce fermentation. Korean native Maeju loaves collected from 5 Do's were separated into surface and inner parts. Four different soy-sauces-the surface part Maeju fermented soy-sauce, the inner part, the surface and inner part combined Maeju fermented soy-sauce, and the semi-Japanese type soy-sauce were fermented and the changes of fermentation microorganism flora and the various chemical components during the period of their fermentations were studied. Besides, 14 home-made soy-sauces collected from 14 different places all over Korea were examined in comparison with the laboratory soy-sauces and to determine the characteristics of Korean native soy-sauce. The results were as follows: 1. The main microorganisms in Korean native soy-sauce fermentation were determined as; Aerobic bacteria: Bacillus subtilis, Bacillus pumilus Lactic acid bacteria: Pediococcus halophilus, Leuconostoc mesenteroides Yeasts: Torulopsis datila, Saccharomyces rouxii 2. Microflora changes during Korean native soy-sauce fermentation were as follows; Aerobic bacteria increased until the 2nd week of fermentation and then gradually decreased. The lactic acid bacteria increased until the 3rd week, after which decreased. When the lactic acid fermentation lowered the pH value to below the 5.4, yeasts were able to grow and participate the fermentation. As the production of organic acids amounted, to a certain height, the growth of all microorganisms lead to the period of decline or death at about the 2nd month of fermentation. After boiling of soy-sauce most microorganisms except a few of Bacillus sp. disappeared. Occosionally yeasts and lactic acid bacteria survived depending upon the composition of soy-sauce. 3. Changes of general chemical components influencing the microflora were investigated for the period of Korean native soy-sauce fermentation. Tetal acidity, salt concentration and total nitrogen were increasing steadily over the entire period of fermentation. pH values were dropping to a certain degree of about 4.5. Salt concentration and pH value seemed to be the important factors influencing the microflora. 4. The microflora were influenced by chemical components of soy-sauce. Aerobic bacteria were able to survive in all soy-sauce as they made spores. Growth of lactic acid bacteria was inhited at 23-26% of salt concentration and pH 4.8. Soy-sauce yeasts started to grow only at pH below 5.4 and seemed to be inhibited at around 26% of salt concentration under pH 4.5-4.7. 5. The open kettle boiling of soy-sauce, the characteristic process of Korean native soy-sauce manufacturing, was effective to sterilize microorganisms, increase the salt concentration, and coagulate proteins. 6. The average viable cell counts of microorganism found in collected samples of home-made Korean native soy-sauces were; Aerobic bacteria: $53{\times}10^2\;cell/ml$ Lactic acid bacteria: 34 cell/ml Yeasts: 14 cell/ml The average values of chemical compositions of samples of home-made Korean native soy-sauce were; Salt concentration: 28.9% pH value: 4.79 Total acidity(lactic acid): 0.91g/100ml Total nitrogen: 1.09g/100ml

• Journal of the Korean Magnetics Society
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• v.19 no.5
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• pp.180-185
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• 2009

Fe$_3$O$_4$ particles, prepared by a sol-gel method, were examined for their structural characteristic, particle shapes and sizes, and their magnetic properties. Two different chemical compositions (using a mol rate Fe$^{2+}$/Fe$^{3+}$ = 1/2 and only Fe$^{2+}$) and 2-methoxyethanol were used for making proper solutions. And the solutions were refluxed and dry in a dry oven and the samples were fired at 200$\sim$600$^{\circ}C$ in the N$_2$ atmosphere. The formation of single-phased spinel ferrite powders was identified with the X-ray diffraction measurement as they were fired at above 250$^{\circ}C$. The result of scanning electron microscopy measurement showed the increase of annealing temperature yielded the particle size increased. The magnetic transition was observed using the Mossbaur spectroscopy measurement. As the ferrite, prepared with the chemical composition (Fe$^{2+}$/Fe$^{3+}$ = 1/2), was fired at 250$^{\circ}C$, 78% of the ferrite had a ferrimagnetic property and 22% of the ferrite was non-magnetic. In case of preparing the sample with only Fe$^{2+}$ and annealed at 200$^{\circ}C$, it had a single phased spinel structure but its particle size was too small to be ferrimagnetic. The annealing temperature above 250$^{\circ}C$ made powders a spinel structure regardless of the preparation method. They had a typical soft magnetic property and their saturation magnetization and coercivity became larger as the annealing temperature increased.