• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.107-118
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• 2000

For the last several decades, the fate of organic pollutants has been extensively studied in natural environments with emphasis on sorption and desorption phenomena. Although the mechanisms involved are not clear yet there is a consensus about the existence of hysteresis in the sorption and desorption of organic pollutants. Furthermore, it is found that hysteresis is the outcome of slow nonequilibrium sorption of organic pollutants, which results in the formation of desorption-resistant fractions of the pollutants. Desorption-resistant fractions may increase as a function of the residence time of the pollutants in the environments. Field monitoring data show a slow but continuous decline of chemicals applied to soil, followed by little or no subsequent disappearance. One plausible explanation for such resistance to biodegradation, desorption, or extraction can be attributed the gradual movement of organic pollutants to less accessible remote sites inside the matrix with time. This phenomenon has been termed sequestration or aging. The fact that some pollutants are sequestered in soil with time may have a great impact on bioremediation and risk assessment, Some portion of the resistant pollutants may still be present in the environments after bioremediation. It requires vigorous means to completely remove the aged portion that may not be further bioavailable. However, precaution should be taken since aging is not always evident. Aging seems to be soil and chemical specific.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.123-123
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• 1998

A number of uracil derivatives have been developed as anti-AIDS drugs having a mechanism of inhibiting cellular reverse transcriptase. A simple and rapid assay technique for recently synthesized KR-V analogues was developed using a high-performance liquid chromatography, and oral pharmacokinetics was examined for assessing their oral bioavailabilites. Plasma samples were analyzed by reversed-phase HPLC using an ODS column with an ultraviolet detection system. All the analogues were eluted within 12 min and the LOQ was 15-30 ng/$m\ell$. The extraction recoveries were higher than 85%, except KR-V1039, 1068 and 1720 having ester group. This chromatic method was well applied to the kinetic studies for KR-V analogues. Among 16 analogues tested in the present work, the 6 compounds including KR-V1123, 1122, 1784, 1783, 1736 and 1700 were found to be bioavailable for oral administration to rats.

• Journal of Microbiology and Biotechnology
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• v.19 no.6
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• pp.604-609
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• 2009

To investigate the potential use of microbial heme as an iron source, recombinant Escherichia coli coexpressing ALA synthase (HemA) as well as the NADP-dependent malic enzyme (MaeB) and dicarboxylic acid transporter (DctA) were cultured. The typical red pigment extracted from the recombinant E. coli after 38 h showed highest absorbance at 407 nm, and the amount of iron in 38.4 mg of microbial heme extract derived from 6-1 fermentation broth was 4.1 mg. To determine the commercial potential of the recombinant E.coli-synthesized iron-associated heme as an iron source, mice were fed the iron-free provender with the microbial heme extract. The average body weight reduction of mice fed non-iron provender was 2.3%, whereas no detectable weight loss was evident in mice fed microbial heme addition after 15 days. The heme content of the blood from microbial heme fed mice was 4.2 mg/ml whereas that of controls was 2.4 mg/ml, which implies that the microbial heme could be available for use as an animal iron source.

• Environmental Engineering Research
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• v.24 no.4
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• pp.654-661
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• 2019

This study assessed the stabilization of fluorine (F)-contaminated soil using calcium hydroxide (Ca(OH)₂) and the consequent changes in human health risk. The bioavailable F decreased to 3.5%, (i.e., 57.9 ± 1.27 mg/kg in 6% Ca(OH)₂-treated soil sample) from 43.0%, (i.e., 711 ± 23.4 mg/kg in control soil sample). This resulted from the conversion of water-soluble F to stable calcium fluoride, which was confirmed by XRD spectrometry. Soil ingestion, inhalation of fugitive dust from soil, and water ingestion were selected as exposure pathways for human health risk assessment. Non-carcinogenic risks of F in soils reduced to less than 1.0 after stabilization, ranging from 4.2 to 0.34 for child and from 3.0 to 0.25 for adult. Contaminated water ingestion owing to the leaching of F from soil to groundwater was considered as a major exposure pathway. The risks through soil ingestion and inhalation of fugitive dust from soil were insignificant both before and after stabilization, although F concentration exceeded the Korean soil regulatory level before stabilization. Our data suggested that substantial risk to human health owing to various potential exposure pathways could be addressed by managing F present in soil.

• Journal of the Speleological Society of Korea
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• no.92
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• pp.9-18
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• 2009

A number of closed metal mines act as point sources of contamination on nearby streams, soils and plants in our country. The contamination of twelve decomposed samples had earned from nine closed metal mines had been evaluated by TEA-3000. The contents of heavy metal with ion fraction exchange and carbonate fraction forms had been showed that the speciation of heavy metals represented with easy solubility, mobility and bioavailable of plants, and in case of sulfide compounds and organic residuals forms are related with the speciation of metals which may be stable forms because of strong bindable capacity. Also heavy metals elements in mosts of mines got with relative stable within crystal lattice, but results of trace element analyser showed that, in the most of tailings from mine areas, large portions of concentration of heavy metals were explained as stable from, sulfides/ organics and residual. In tailing from Imchun mines, the concentrations extracted by water were relatively high as compared with other mine areas whose total concentrations were very high because of large quantities of exchangeable ions and carbonates and low soil pH. Danger Index (D.I.) suggested in this study was based on the cumulative concentrations of step 1 and 2 from the result of trace element analyser. When the soil pH was considered, this index became better indicator to determine the priority for the remediation of mine area.

• Journal of Nutrition and Health
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• v.30 no.4
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• pp.425-433
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• 1997

Levels and distribution of five B-6 vitamers(PMP, PM, PLP, PL, and PN) and pyridoxine $\beta$-glucoside conjugates(PN-glucoside) were examined in milk of American women who received supplements of 2.5 or 10mg PN HCl/d and of unsupplemented Egyptian women during the first six months of lactation. B-6 vitamer and PN-glucoside levels in human milk were determined by reverse-phase HPLC. Pyridoxal(PL), which has been reported to be the most rapidly absorbed form of vitamin B-6 and may facilitate bioavailability, was the predominant vitamer in human milk of all three groups. Pyridoxal made up 72% of total vitamin B-6 for the 2.5mg supplemented group, 76% for the 10mg group, and 59% for the Egyptian group. Level and Percent PL were significantly lower for Egyptian women. Mean growth of the two American groups was similar to each other and within the normal range of the NCHS reference, however, Egyptian infants showed growth faltering at 6 months. The Percent of PN-glucoside, a less bioavailable form of vitamin B-6 in humans was 1% in milk of American women and was 11% in Egyptian women and these values were significantly different. for Egyptian women, total vitamin B-6 levels in breast milk correlated Positively with animal protein intake(r=0.91) and percent PN-glucosides(r=0.53) and negatively with plant protein intake(r=-0.55). These findings showed that high plant protein intake was associated with low concentrations of PL and total vitamin B-6 in human milk.

• Food Engineering Progress
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• v.14 no.4
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• pp.342-345
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• 2010

The purpose of current study was to examine bioaccessibility of antioxidant activity and total phenolic content in each part of water spinach (Ipomoea aquatic Forsk.). In vitro biomimicking system simulated human digestive fluid was employed in order to measure bioavailable anti-oxidative effect and phenolic content. Antioxidant activity and total phenolic content was measured by using the DPPH method and the Folin-Ciocalteu assay, respectively. Stem of water spinach had a higher DPPH free radical scavenging effect (5.43 mg/mL for $IC_{50}$) than leaf (5.95 mg/mL for $IC_{50}$), while leaf had a greater level of total phenolic content (287.45 ${\mu}g$ GAE/mL) than stem (216.45 ${\mu}g$ GAE/mL). Bioaccessible antioxidant capacity and digestive stability of total phenolic content showed a similar pattern to what found in raw materials. Our result also indicated that total phenolic content was not found to be a major marker for prediction of antioxidant activity. It is plausible that other constituents such as vitamin E and C in water spinach could be contributors for antioxidant activities.

• The Korean Journal of Food And Nutrition
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• v.32 no.2
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• pp.133-137
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• 2019

Curcumin is a hydrophobic polyphenol extracted from turmeric that exhibits a variety of biological functions has albeit with limited efficacy as a functional food material owing to its low absorption when administered orally. The newly developed curcumin powder formulation exhibits improved absorption rate in vivo. This study evaluates the anti-oxidant effects of $Theracurmin^{(R)}$ (TC), which is highly bio-available in curcumin powder. The antioxidant activity of TC was investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, ferrous reducing antioxidant power (FRAP) assays, NO radical, superoxide radical, $H_2O_2$ scavenging activity, and total antioxidant capacity (TAC). Additionally, we evaluated the antioxidant activity of TC in high-fat diet (HFD)-fed streptozotocin (STZ)-induced Type 2 diabetic rats. As a result of oral administration of TC for 13 weeks in type 2 diabetic rats, the group administration of 2,000 mg/kg significantly increased FRAP, superoxide dismutase (SOD), and reduced the level of glutathione (GSH) in liver tissue 1.9, 1.2, and 1.2-times, respectively. Furthermore, serum TAC levels increased by 1.3-fold after the rats were administered with a dose of 500 mg/kg. These results were consistent with the in vitro assay results. In conclusion, TC exhibited its potential as a functional food material through its antioxidant properties.

• Korean Journal of Agricultural Science
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• v.43 no.1
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• pp.14-20
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• 2016

One of the most powerful health management practices is the use of antibiotics, but their use is being restricted because of health safety issues. The swine industry has been looking for various alternatives to antibiotics and increasingly considers the use of dietary factors like feed ingredients, feed additives, feed formulation practices, or feeding methods, instead of using antibiotics to improve pig health and performance. Among other alternatives to antibiotics, spray-dried plasma may be a candidate. Spray-dried plasma is a blood product that provides bioavailable nutrients and physiologically active components such as immunoglobulins, glycoproteins, growth factors, peptides, etc. It is an excellent protein source with balanced and highly digestible amino acids. Several beneficial physiological activities depend on components of spray-dried plasma, such as immune competence (antibacterial activity), modulation of microbiota and/or immune system, integrity of intestinal barrier function, etc. These beneficial effects can contribute to improvement of pig performance and health by modulation of microbiota in the digestive tract and/or immune system. Therefore, it is suggested that spray-dried plasma has great potential as an antibiotics alternative.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.5
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• pp.689-694
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• 2016

The objective of the current study was to evaluate the effect of supplementation of either L-methionine (L-Met) or DL-methionine (DL-Met) to diets of starter pigs on nitrogen (N) balance, metabolism, and serum amino acid profile. Eighteen crossbred ($Duroc{\times}Landrace{\times}Yorkshire$) barrows weighing $15.45{\pm}0.88kg$ were randomly allotted to 1 of 3 diets with 6 pigs per treatment. The diets included a basal diet (Met-deficient diet) containing 0.24% standardized ileal digestibility Met with all other essential nutrients meeting the pig's requirements. The other two diets were produced by supplementing the basal diet with 0.12% DL-Met or L-Met. The experiment lasted for 18 days, consisting of a 13-day adaptation period to the diets followed by a 5-day experimental period. Pigs were fed ad libitum and free access to water throughout the experiment. Results showed that the supplementation of either L-Met or DL-Met improved N retention, and serum methionine concentration, and decreased N excretion compared with basal diet (p<0.01). The N retention of pigs fed diets supplemented with the same inclusion levels of DL-Met or L-Met were not different (p>0.05). In conclusion, on equimolar basis DL-Met and L-Met are equally bioavailable as Met sources for starter pigs.