• Advances in materials Research
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• v.4 no.4
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• pp.193-205
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• 2015

Contamination by bacterial strands is a major problem after bone replacement surgeries, so there is a great need to develop low cost biocompatible antibacterial bioactive scaffolds to be used in bone tissue engineering. For this purpose, nano-zinc doped hydroxyapatite with different zinc-concentrations (5, 10 and 15 mol%) was successfully prepared by the wet chemical precipitation method. The prepared powders were used to form porous scaffolds containing biodegradable Ca-cross-linked alginate (5%) in order to enhance the properties of alginate scaffolds. The scaffolds were prepared using the freeze-gelation method. The prepared powders were tested by X-ray diffraction; transmission electron microscope and Fourier transform infrared analyses, while the prepared scaffolds were investigated by Fourier transform infrared analyses, thermogravimetric analyses and measurement of the antibacterial properties. Best results were obtained from scaffold containing 15% mol zinc-doped hydroxyapatite powders and 5% alginate concentration with ratio of 70:30.

• The Korean Journal of Food And Nutrition
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• v.31 no.6
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• pp.821-827
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• 2018

Ecklonia cava which is a kind of phaeophyta and belongs to Laminariales Alariaceae is a perennial seaweed distributed over Jeju and Dokdo islands. The purpose of this study evaluate antioxidant activities of Ecklonia cava crackers. Crackers were prepared with different measurements (0, 2, 4, 6, 8 g) of Ecklonia cava; indicated as S1, S2, S3, S4 and S5, and are used to examine and compare antioxidant activities, and quality characteristics. Ecklonia cava powder was used, after being extracted with 70% ethanol in hot water and done in freeze dehydration. To examine antioxidant activities of Ecklonia cava and cracker, DPPH radical scavenging activity, total phenolic and reducing power were tested. Total phenolic content was 36.86 mg GAE/g. DPPH radical scavenging activity and reducing power showed good vitality as amounts of Ecklonia cava powder increased (p<0.001). pH level decreased as amounts of power increased. L (lightness) values and b (yellowness) values decreased with an increased concentration of Ecklonia cava powder (p<0.001), whereas (redness) values didn't show tendency. S5 indicated the lowest spreadness. According to sensory evaluation, S4 (6 g) was preferred the most in terms of color, flavor, taste, appearance, texture, and overall palatability. Results suggest that Ecklonia cava powder has antioxidant effect and is useful as a functional food resource.

• Polymer(Korea)
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• v.29 no.6
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• pp.599-604
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• 2005

The hyaluronic acid (HA) with excellent biocompatibility has been combined with lactide, the ester dimer of polylactide, with good biodegradability to produce biocompatible materials which can control the period of degradation in a human body. By freeze frying method, HA and lactide were crosslinked with crosslinking agent, 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC). Degree of lactide and EDC reaction was determined by the analysis of nuclear magnetic resonance spectroscopy. Both lactyl group and EDC conversion increased as the mole ratio of lactide to HA increased from 5 to 13. The membrane swelled less and became more brittle with the more addition of lactyl group resulting from the higher mole ratio of lactide to HA. Swelling ratio decreased and tensile modulus increased due to the more addition of lactyl group as the EDC concentration increased or reaction temperature decreased. Drug release experiment from various membranes with different degree of crosslinking showed that permeability decreased with increasing degree of crosslinking. The degradation became slower with the more addition of lactyl group. Mechanical property and degradation rate of the synthesized membrane were shown to be controlled through adjusting operation parameters such as mole ratio, temperature, and crosslinking agent concentration.

• Food Science of Animal Resources
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• v.37 no.2
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• pp.228-241
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• 2017

Hematological, chemical and functional characteristics of porcine, chicken and duck blood were evaluated. A porcine blood sample showed the most abundant red blood cell, hemoglobin concentration, packed cell volume and plasma protein content as well as its freeze-dried blood possessed the highest contents of protein, fat, Cu and Cr with the highest percentage of heme iron (p<0.05). Unlike porcine blood, chicken blood showed a well balance in some essential amino acids, specifically for a higher isoleucine content (p<0.05). Furthermore, it possessed the highest contents of carbohydrate, Zn and non-heme iron (p<0.05). The most rapid response to form a strong gel, especially at $70^{\circ}C$ and $80^{\circ}C$, was found in chicken blood, followed by duck and porcine blood, respectively. The result of emulsion activity index (EAI) and emulsion stability index (ESI) at the low protein concentration indicated that chicken blood had the most superior emulsion properties (p<0.05). Regarding duck blood, it exhibited the highest content of Mg and Mn (p<0.05). Moreover, duck blood had similar foaming properties to porcine blood in which they showed higher values than chicken blood (p<0.05). Specific characteristics of blood were therefore diminished by animal species in which this information could be used as food supplementation or product development based on their potential applications.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.2
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• pp.87-90
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• 2002

$LiCoO_{2}$ powders were synthesized at various temperatures using lithium hydroxide and cobalt hydroxide as precursors prepared by precipitation process and freeze-drying. In this study, the$LiCoO_{2}$ samples were synthesized via a solid state reaction with various LiOH concentration between 10 % and 30 % excess. And $LiCoO_{2}$powders were calcined at 600~$800^{\circ}C$ in a short time. Measurements of XRD and SEM were performed to characterize the properties of the prepared materials. The effect of amount of Li ions on the structural change in powder has been examined using the XRD analysis. For the not added excess of LiOH, CoOOH phase presented in the XRD pattern of $LiCoO_{2}$ due to loss of Li ions during firing. The morphology and particle size of the powders were examined using SEM. The obtained powders are high temperature-$LiCoO_{2}$HT-LiCoO$_{2}$) and homogeneous with the range of grain size in the order of hundreds of nanometers. The effects of variation of LiOH concentration on the structural change in powder were investigated using the Rietveld analysis. As an analysis result, c/a is constant by 4.99 on all occasions. Finally, the structure of HT-$LiCoO_{2}$ was simulated by the commercial software $Creius^{2}$(Molecular Simulations, Inc.) from the results of Rietveld analysis.

• Korean journal of food and cookery science
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• v.14 no.5
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• pp.498-502
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• 1998

In order to develop a natural food preservative, freeze dried plantain (Plantago asiatica L.) was extracted with several solvents, and the antimicrobial activity was investigated. The methanol extract exhibited antimicrobial activites against five strains of bacteria such as Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, and Vibrio parahaemolyticus. The methanol extract at the concentration of 1.0 mg/ml completely inhibited the growth of B. subtilis and V. parahaemolyticus. Antimicrobial activity of the ethylacetate fraction from the methanol extract was the strongest compared with those of other solvent fractions such as n-hexane, chloroform, n-butanol and water. The ethylacetate fraction showed the inhibitory effect at the concentration of 0.5 mg/disc on the growth of B. subtilis and V. parahaemolyticus.

• Preventive Nutrition and Food Science
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• v.11 no.2
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• pp.94-99
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• 2006

This study investigated the protective effect of the butanol (BuOH) fraction from Laminaria japonica (BFLJ) extract on high glucose-induced oxidative stress in human umbilical vein endothelial cells (HUVECs). Freeze-dried L japonica was extracted with distilled water, and the extracted solution was mixed with ethanol then centrifuged. The supernatant was subjected to sequential fractionation with various solvents. The BuOH fraction was used in this study because it possessed the strongest antioxidant activity among the various solvent fractions. To determine the protective effect of the BFLJ, oxidative stress was induced by exposing of HUVECs to the high glucose (30 mM) or normal glucose (5.5 mM) for 48 hr. Cell viability, lipid peroxidation, glutathione (GSH) concentration, and antioxidant enzyme activities such as catalase, superoxide dismutase (SOD), glutathione peroxidase (GSH-px), and glutathion reductase (GSH-re) were measured. Exposure of HUVECs to high glucose for 48 hr resulted in a significant (p<0.05) decrease in cell viability, SOD, GSH-px and GSH-re and a significant (p<0.05) increase in thiobarbituric acid reactive substances (TBARS) formation in comparison to the cells treated with 5.5 mM glucose or untreated with glucose. BFLJ treatment decreased TBARS formation and increased cell viability, GSH concentration, and activities of antioxidant enzymes including catalase, SOD, GSH-px, and GSH-re in high glucose pretreated HUVECs. These results suggest that BFLJ may be able to protect HUVECs from high glucose-induced oxidative stress, partially through the antioxidative defence systems.

• Nutrition Research and Practice
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• v.6 no.3
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• pp.187-194
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• 2012

In this study, the antibacterial effect was evaluated to determine the benefits of high speed drying (HSD) and far-infrared radiation drying (FIR) compared to the freeze drying (FD) method. Citrus press-cakes (CPCs) are released as a by-product in the citrus processing industry. Previous studies have shown that the HSD and FIR drying methods are much more economical for drying time and mass drying than those of FD, even though FD is the most qualified drying method. The disk diffusion assay was conducted, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined with methanol extracts of the dried CPCs against 11 fish and five food-related pathogenic bacteria. The disk diffusion results indicated that the CPCs dried by HSD, FIR, and FD prevented growth of all tested bacteria almost identically. The MIC and MBC results showed a range from 0.5-8.0 mg/mL and 1.0-16.0 mg/mL respectively. Scanning electron microscopy indicated that the extracts changed the morphology of the bacteria cell wall, leading to destruction. These results suggest that CPCs dried by HSD and FIR showed strong antibacterial activity against pathogenic bacteria and are more useful drying methods than that of the classic FD method in CPCs utilization.

• Polymer(Korea)
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• v.28 no.2
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• pp.194-200
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• 2004

Porcine small intestine submucosa (SIS) has been widely used as a biomaterial without immunorejection responses. Crosslinked SIS sponges were characterized for the possibility of the bio-interactive wound dressings and tissue engineered scaffolds. SIS powders were dissolved in 3% acetic acid aqueous solution at 48hrs followed by pouring into mold and then fabricated by freeze-drying method. SIS sponge was prepared by crosslinked with 1-ethyl-(3-3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC) solution (deionized water: ethanol=5:95) with 1-100mM concentration for 24 hrs and Iyophilized. SIS sponges were characterized by scanning electron microscopy, differential scanning calorimeter, and Fourier transform infrared spectrometer and were tested their porosity and water absorption ability. It was observed that the concentration of EDC might be exceeded 50 mM to get good physical characteristics. In conclusion, it seems that SIS sponge could be very useful for the applications of wound healing and tissue construction.

• Korean Journal of Veterinary Research
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• v.30 no.4
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• pp.487-497
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• 1990

This study was carried out to observe in vitro effect of praziquantel on the tegumental changes of Heterophyopsis continua with scanning electron microscope. Metacercariae were collected from the perch, Lateolabrax japonicus, by artificial digestion technique and fed to 2-week old chickens. Adult worms were recovered from small intestine of chickens 8 days after infection. For working solutions, praziquantel was diluted with TC199 medium at concentration of 0.01, 0.1. 1 and $10{\mu}g/ml$. To each petri dish containing 10ml of solution, 5~10 worms were introduced and incubated at $37^{\circ}C$. For the scanning electron microscopy(SEM), the worms were fixed in cold 2.5% glutaraldehyde, dehydrated in a series of graded ethanol and freeze-dried. Dried specimen was mounted on stub and coated with gold and observed in an SEM. The results were as follows: 1. Severe tegumental alterations were recognized by scanning electron microscope. Bleb formation of tegument was observed in 5 minute group and most pronounced on anterior tegument of worms. The number and size of blebs increased as incubation time prolonged. 2. The surface destruction was more pronounced at ventral margin between the oral and the ventral suckers. 3. The sensory papillae were slightly affected, but destruction of tegumental spine was not recognized. 4. The effect of praziquantel on the worm was found dependent on the concentration and incubation time, however, the effect was more dependent upon the incubation time.