• Journal of Radiation Protection and Research
• /
• v.14 no.2
• /
• pp.10-17
• /
• 1989

A study for the assessment of dose given by outdoor radon to respiratory system has been carried out by making use of radon-cups containing CR-39 plastic track detectors. Detection efficiencies were determined by irradiation of the radon-cups in a standard radon chamber of known concentration. Thus determined detection factors of CR-39 plastic track detector in bare, open cup and filtered cup geometry are found to be 0.273, 0.0813 and 0.0371 $trmm^{-2}$/(37$Bqm^{-3}{\cdot}d$), respectively, which are chemically etched in 30% NaOH solution of $70^{\circ}C$ for 220 minutes. The outdoor radon concentrations measured at Taejeon(Chungnam National University) from May 1988 to March 1989 are in the range of 27.4 - 135.8 Bq/$m^3$(0.74 - 3.67pCi/l)by open cup and 16.7 - 143.9 Bq/$m^3$(0.45 - 3.89 pCi/l) by filtered cup, which yield overall annual average value of outdoor radon concentration of $70.8Bq/m^3$(1.91 pCi/l). Corresponding effective dose equivalent rate to respiratory system of ICRP standard man is assessed to be 520 nSv /h.

• Asian-Australasian Journal of Animal Sciences
• /
• v.30 no.5
• /
• pp.653-659
• /
• 2017

Objective: This trial was performed to examine the effects of ruminally degradable starch (RDS) levels in total mixed ration (TMR) with low corn-based starch on the milk production, whole-tract nutrient digestibility and nitrogen balance in dairy cows. Methods: Eight multiparous Holstein cows (body weight [BW]: $717{\pm}63kg$; days in milk [DIM]: $169{\pm}29$) were assigned to a crossover design with two dietary treatments: a diet containing 62.3% ruminally degradable starch (% of total starch, low RDS) or 72.1% ruminally degradable starch (% of total starch, high RDS). Changes to the ruminally degradable levels were conducted by using either finely ground corn or steam-flaked corn as the starch component. Results: The results showed that dry matter intake, milk yield and composition in dairy cows were not affected by dietary treatments. The concentration of milk urea nitrogen was lower for cows fed high RDS TMR than low RDS TMR. The whole-tract apparent digestibility of neutral detergent fiber, acid detergent fiber and crude protein decreased, and that of starch increased for cows fed high RDS TMR over those fed low RDS TMR, with no dietary effect on the whole-tract apparent digestibility of dry matter and organic matter. The proportion of urinary N excretion in N intake was lower and that of fecal N excretion in N intake was higher for cows fed high RDS TMR than those fed low RDS TMR. The N secretion in milk and the retention of N were not influenced by the dietary treatments. Total purine derivative was similar in cows fed high RDS TMR and low RDS TMR. Consequently, estimated microbial N flow to the duodenum was similar in cows fed high RDS TMR and low RDS TMR. Conclusion: Results of this study show that ruminally degradable starch levels can influence whole-tract nutrient digestibility and nitrogen balance in dairy cows fed low corn-based starch diets, with no influence on performance.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.11
• /
• pp.1395-1400
• /
• 2008

This study was aimed to analyze the nutritional components and anticancer properties of Haesongi mushroom (Hypsizigus marmoreus), which has been recently available in Korea, to estimate its nutritional and functional values. Fruit body of Haesongi mushroom was investigated for its proximate components and mineral contents. Its water and ethanol extracts were compared for nutritional components such as $\beta$-glucan, protein, and total sugar. Anticancer effects of both extracts were measured against human cancer cell lines in vitro. This mushroom contained high protein (22.63%), total dietary fiber (30.80%), and K (3383.3 mg/100 g). The water extract contained more nutritional components such as $\beta$-glucan (9.32 mg/g), protein (17.71%), and total sugar (39.93%), compared with the ethanol extract. Moreover the extraction yield of the water extract was higher than the ethanol extract. The growth inhibitory effects of the water extract (5 mg/mL) on AGS, HepG2, and SW480 human cancer cells were 90.61, 75.43, and 58.49%, respectively. However, the ethanol extract showed 81.79, 49.90, and 25.71% growth inhibition, respectively. In this study, it is demonstrated that water is a more efficient solvent than ethanol for extracting nutritional and functional components from Haesongi mushroom.

• Journal of the Mineralogical Society of Korea
• /
• v.25 no.4
• /
• pp.283-293
• /
• 2012

In order to have better insights into the chemical differentiation of Earth from its magma ocean phase to the current stratified structure, detailed information of crystallization kinetics of silicate melts consisting of the magma ocean is essential. The structural transitions in oxide glasses and melts upon crystallization provide improved prospects for a systematic and quantitative understanding of the crystallization processes. Here, we report the $^{27}Al$ 3QMAS NMR spectra for sol-gel synthesized $Al_2O_3$ glass with varying temperature and annealing time. The NMR spectra for the amorphous $Al_2O_3$ show well-resolved Al coordination environments, characterized with mostly $^{[4,5]}Al$ and a minor fraction of $^{[6]}Al$. The fraction of $^{[5]}Al$ in the alumina phase decreases with increasing annealing time at constant temperature. The NMR results of $Al_2O_3$ phases also imply that multiple processes (e.g., crystallization and/or changes in structural disorder within glasses) could involve upon its phase transition. The current results and method can be useful to understand crystallization kinetics of diverse natural and multi-component silicate glasses and melts. The potential result may yield atomic-level understanding of Earth's chemical evolution and differentiation from the magma ocean.

• Korean Chemical Engineering Research
• /
• v.54 no.4
• /
• pp.443-447
• /
• 2016

The microalgae have cellulose as a main structural component of their cell wall and the lignin content in microalgae is much lower than other lignocellulosic biomass. Therefore, fermentable sugar production from microalgae (Tetraselmis KCTC 12236BP) can be carried out under pretreatment without high temperature and high pressure. It was investigated that the effect of hot-water pretreatment using sulfuric acid for lipid extracted algae which is expected to be a next generation biomass. The effects of three major variables including extraction temperature, acid concentration and time on the enzymatic hydrolysis were investigated. Among the tested variables, temperature and acid concentration showed significant effects and optimum pretreatment conditions for the economic operation criteria were obtained as follows: reaction temperature of $120^{\circ}C$, sulfuric acid concentration of 2 mol and pretreatment time of 40 min. Under the optimum conditions of acidic hot water pretreatment, experimentally obtained hydrolysis yield were 95.9% which showed about 2.1 fold higher compared with enzymatic hydrolysis process. Therefore, acid pretreatment under mild condition was proven to be an effective method for fermentable sugar production from lipid extracted microalgae.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.55 no.4
• /
• pp.292-298
• /
• 2010

This study aims to understand the contribution rate of plant parts on biomass in five winter forage crops including barley, wheat, oat, rye and triticale. In barley and oat, the major plant parts on dry matter yields were changed from culm to spike at 20 days after heading(DAH), but culm was very important part on biomass of rye, wheat and triticales until 30DAH. Wheat, rye and triticales showed same pattern in dry weight increase indicating that culm was main component of biomass from heading stage but spike became heavier after 30 DAR. Barley and oat were similar in dry weight increase where spike was the main components of biomass at 20 DAR. After heading stage the major biomass of most winter forage crops were dependent on the weight of culm and spike, while the contribution of leaves to plant biomass was lower as compared to culm and spike. Thus culm and spike were very important factors for improving the dry matter production of winter forage crops breeding and early maturing is also additively required under Korean climatic condition.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.3 no.1
• /
• pp.73-83
• /
• 1995

Effect of water treatment sludge(alum sludge) application on the growth of Korea local corn(Zeas Mays L.) was evaluated and phytotoxicity of alum sludge on the growth of corn roots and plant height was tested. Alum sludge itself and composted alum sludge compost were applicated by 1500kg/ha in the plot respectively. For the fertility test, yield, chlorophyll content, plant height of corn treated by alum sludge and composted alum sludge were better than that of control. No clear toxixity of alum sludge was found. At the food chemical analyses of seed corn, no obvious component variation were evaluated either. Test of pH effect on phytotoxicity of alum sludge on corns showed that plant height and root growth of corns were inhibited at low pH 4 solution. Phytotoxicity test of alum sludge extract which was extracted at various pH solutions, showed that growth and cations uptake inhibition were found the more serious the lower the pH. Plant height and root growth injury were serious at higher than 100ppm Al content solution.

• Journal of Plant Biotechnology
• /
• v.29 no.2
• /
• pp.139-144
• /
• 2002

Sterols play two major roles in plants: a bulk component in biological membranes and precursors of plant steroid hormones. Physiological effects of plant steroids, brassinosteroids (BRs), include cell elongation, cell division, stress tolerance, and senescence acceleration. Arabidopsis mutants that carry genetic defects in BR biosynthesis or its signaling display characteristic phenotypes, such as short robust inflorescences, dark-green round leaves, and sterility. Currently there are more than 100 dwarf mutants representing 7 genetic loci in Arabidopsis. Mutants of 6 loci, dwf1/dim1/cbb1, cpd/dwf3, dwf4, dwf5, det2/dwf6, dwf7 are rescued by exogenous application of BRs, whereas bri1/dwf2 shares phenotypes with the above 6 loci but are resistant to BRs. These suggest that the 6 loci are defective in BR biosynthesis, and the one locus is in BR signaling. Biochemical analyses, such as intermediate feeding tests, examining the levels of endogenous BR, and molecular cloning of the genes revealed that dwf7, dwf5, and dwf1 are defective in the three consecutive steps of sterol biosynthesis, from episterol to campesterol via 5-dehydroepisterol. Similarly, det2/dwf6, dwf4, and cpd /dwf3 were shown to be blocked in D$^4$reduction, 22a-hydroxylation, and 23 a-hydroxylation, respectively. A signaling mutant bril/dwf2 carries mutations in a Leucine-rich repeat receptor kinase. Interestingly, the bri1 mutant was shown to accumulate significant amount of BRs, suggesting that signaling and biosynthesis are dynamically coupled in Arabidopsis. Thus it is likely that transgenic plants over-expressing the rate-limiting step enzyme DWF4 as well as blocking its use by BRIl could dramatically increase the biosynthetic yield of BRs. When applied industrially, BRs will boost new sector of plant biotechnology because of its potential use as a precursor of human steroid hormones, a novel lead compound for cholesterol-lowering effects, and a various application in plant protection.

• Korean Journal of Food Science and Technology
• /
• v.27 no.2
• /
• pp.230-234
• /
• 1995

Angiotensin converting enzyme(ACE) inhibitory peptides lowering blood pressure were fractionated from a commercial soybean paste(Doenjang). When the freeze-dried sample of soybean paste was extracted with cold water, the recovery yield of total nitrogen(TN) was shown to be 73.3% in 30 minutes. The cold water extract was filtered through PM-10 membrane(Amicon) for 3 hours in order to remove high molecular weight polypeptides. The TN and salt of ultrafiltrate were recovered to 80.8% and 99.2%, respectively, and its ACE $IC_{50}$ was $41.8{\mu}g/ml$. When the ultrafiltrate was divided into 7 fractions by reverse phase prep-HPLC, F5 fraction showed the highest ACE inhibitory activity ($IC_{50}=6.8{\mu}g/ml$) and salt could be collected into F1 fraction. Subsequently, the F5 fraction was divided into another five fractions by ion exchange prep-HPLC, all of which appeared to be high ACE inhibitory activity($IC_{50}=2.5{\sim}8.3{\mu}g/ml$). Among them, F53 fraction had the highest ACE inhibitory activity, and its main amino acid component was found to be histidine.

• Applied Biological Chemistry
• /
• v.39 no.4
• /
• pp.268-273
• /
• 1996

Fundamental data for new type of product development from Lycii fructus was experimentally determined. The chemical composition, and Hunter value changes, optimum extraction, volatile components of extract under different extraction conditions and heat treatment were mainly studied. Results are summarized as follows. The proximate compositions of dried Lycii fructus were water 21.8%, total sugar 27.6%, reducing sugar 15.2%, crude protein 14.29%, crude fat 5.65%, crude fiber 7.48%, and ash 7.98% in percent stale, respectively. Extracted yield on the basic of solid extract was getting increased when more solvent was used for extraction. The most recommendable extraction was 1 to 10 part of sample to solvent ratio. When water was employed as extraction solvent, the highest amount of solid extract was obtained. Extract of Lycii fructus in terms of yields and color was most acceptable when raw sample was treated 8 minute roasting at $180^{\circ}C$ and 60 minute heating at $120^{\circ}C$, respectively. Major volatile components of fresh Lycii fructus were to hexadecanoic acid, methyl linoleate, benzyl alcohol, dimetane benzene by GC/MS. By the roasting of raw sample, the compounds of 2-methyl-2buthenal, 1,4-dimethyl benzene, and benzyl alcohol were reduced. Wheras, methyl thiopropanol, benzene acetaldehyde and ethyl linoleate were slightly increased.