• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.86-91
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• 1995

In order to expand the utility of alginic acid in the food industry, we have investigated to prepare low viscous alginic acid using a method for degradation of alginic acid with the enzyme system of Vibrio sp. AL-145. The enzyme showed maximum activity at pH 8.0 and $37^{\circ}C$, and was stable in the pH range 7.5 to 8.5 and at temperature up to $30^{\circ}C$, and 0.5M NaCl needed for the enzyme activity. The viscosity of alginic acid decreased with the reaction time courses regardless of alginic acid and enzyme concentration, and 90% of viscosity decreased with 60 min of reaction time, but the changes of reducing sugar not exhibited. The soluble concentration of partially degradated alginic acid(PDA) in water was about 10%(w/v), and adsorption capacity of $Ca^{2+}$ ion increased with increasing the concentration of PDA. The alcohol concentration on precipitation of PDA was higher than Na-alginic acid.

• Research in Community and Public Health Nursing
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• v.13 no.3
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• pp.471-480
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• 2002

Objectives: This study was designed to provide basic information for smoking prevention education for middle school students by examining their knowledge and attitudes toward smoking. Method: A survey was conducted in this study on 1.250 students from 12 middle schools in the six educational bureaus in the Busan region. Results from the preliminary survey showed that the reliability of the instruments for knowledge and attitudes toward smoking were 0.84 and 0.86. respectively. The data for this study were collected for 20 days from Dec. 1 to 20, 2000, and then statistically analyzed with the SAS program using frequency, percentage, mean and standard deviation. and two-way ANOVA. Results: (1) The highest frequency of responses found that both male and female students did not smoke at all. Among 170 students who had experiences of smoking, 66.5% reported they tried smoking because of curiosity, and 38.2% reported they first smoked during the 2nd grade of middle school and 1.2% during 4th grade of primary school. (2) In scores on smoking knowledge, the item with the highest score in both male and female students was one that they had no smoking experiences et al. followed by smoking experiences in the past and experiences of regular smoking. (3) In scores on attitude toward smoking, both male and female students were scored as the highest at the item that they had no smoking experiences et all. followed by the item that they smoked in the past and that they experienced regular smoking. (4) There was no significant correlation between knowledge and attitude toward smoking among the whole subjects (r=0.09. P=0.00). With regard to regular smoking experiences among the male and female students at the 3rd grade of middle school. there was a relatively high correlation between knowledge and attitude toward smoking among them (r=0.57. P=0.00: r=0.56. P=0.01). Conclusion: Students who had never smoked or smoked only in the past need smoking prevention education consistently. Particularly, for those who were regular smokers, not only individualized but also organized in small size groups, they need an intensive educational program on the basis of counseling to reduce smoking and to put in practice smoking cessation.

• Molecules and Cells
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• v.41 no.5
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• pp.413-422
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• 2018

Soybean transgenic plants with ectopically expressed AtABF3 were produced by Agrobacterium-mediated transformation and investigated the effects of AtABF3 expression on drought and salt tolerance. Stable Agrobacterium-mediated soybean transformation was carried based on the half-seed method (Paz et al. 2006). The integration of the transgene was confirmed from the genomic DNA of transformed soybean plants using PCR and the copy number of transgene was determined by Southern blotting using leaf samples from $T_2$ seedlings. In addition to genomic integration, the expression of the transgenes was analyzed by RT-PCR and most of the transgenic lines expressed the transgenes introduced. The chosen two transgenic lines (line #2 and #9) for further experiment showed the substantial drought stress tolerance by surviving even at the end of the 20-day of drought treatment. And the positive relationship between the levels of AtABF3 gene expression and drought-tolerance was confirmed by qRT-PCR and drought tolerance test. The stronger drought tolerance of transgenic lines seemed to be resulted from physiological changes. Transgenic lines #2 and #9 showed ion leakage at a significantly lower level (P < 0.01) than ${\underline{n}}on-{\underline{t}}ransgenic$ (NT) control. In addition, the chlorophyll contents of the leaves of transgenic lines were significantly higher (P < 0.01). The results indicated that their enhanced drought tolerance was due to the prevention of cell membrane damage and maintenance of chlorophyll content. Water loss by transpiration also slowly proceeded in transgenic plants. In microscopic observation, higher stomata closure was confirmed in transgenic lines. Especially, line #9 had 56% of completely closed stomata whereas only 16% were completely open. In subsequent salt tolerance test, the apparently enhanced salt tolerance of transgenic lines was measured in ion leakage rate and chlorophyll contents. Finally, the agronomic characteristics of ectopically expressed AtABF3 transgenic plants ($T_2$) compared to NT plants under regular watering (every 4 days) or low rate of watering condition (every 10 days) was investigated. When watered regularly, the plant height of drought-tolerant line (#9) was shorter than NT plants. However, under the drought condition, total seed weight of line #9 was significantly higher than in NT plants (P < 0.01). Moreover, the pods of NT plants showed severe withering, and most of the pods failed to set normal seeds. All the evidences in the study clearly suggested that overexpression of the AtABF3 gene conferred drought and salt tolerance in major crop soybean, especially under the growth condition of low watering.

• Current Research on Agriculture and Life Sciences
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• v.5
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• pp.40-51
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• 1987

This experiment was conducted to search for Rhizobia with good nitrogen fixation abilities and to investigate their physiological characteristics isolated from 12 soybean cultivars and the affinities of root nodule bacteria with soybeans. The results obtained were as follows; Based on colors, Rhizobia grown on YMA medium were divided into 3 groups, i. e., white, translucent and transparent, amounting to 60, 30 and 10%, respectively. In litmus milk reaction, the strains which produced alkali, acid serum, alkaline serum and acid reached to 51, 29, 9 and 11%, respectively. Strains, S022, and S096 were slow-growers and produced alkaili, while strains, S080, S-090, and S118 were fastgrowers and produced acid. The growth of root nodule bacteria on YMA medium was favorable between the initial pHs of 6.0~7.0. Glutamine, asparagine and al1antoin as nitrogen sources enhanced the growth of root nodule bacteria. All the strains tested formed nodules on the soybean roots, and the strains with good symbiotic nitrogen fixation abilities that had white color, small colony, nitrate reduction abilities and no nitrite reduction abilities showed comparatively high nitrogen fixing activities. Some strains varied in nitrogen fixing activities according to soybean cultivars, and a few strains fanned ineffective nodules which showed no nitrogen fixing activity.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.197-197
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• 2019

총인처리시설에서는 응집제를 주입하여 인이나 오염물질을 침전시켜 처리하고 있으며 PAC(poly aluminum chloride)나 $FeCl_3$, $Al_2(SO_4)_3$, 등 다양한 종류의 응집제가 사용되어지고 있다. 하지만 기존에 사용되어 지고 있는 알루미늄계열의 응집제는 처리수에 잔류이온이 존재하게 되어 인체에 축적돼 알츠하이머 병 등 신체질환을 유발할 수 있는 단점이 있다. 따라서 이러한 단점을 사전에 예방하기 위해 $TiCl_4$와 같은 티타늄계열 응집제에 대한 연구가 진행되고 있다. $TiCl_4$ 응집제는 인 제거에 효과적으로 적용할 수 있으며 수중에 잔류이온을 유발하지 않으며 Ti이온은 치과임플란트나 의료장비로 사용될 만큼 인체에 무해하다고 알려져 있다. 응집제 사용에 따라 생성된 응집슬러지의 처리방안에 있어서 기존 응집제의 경우 생성된 슬러지의 대부분은 하수슬러지 위탁처리업체를 통해 소각 및 매립, 재활용 되고 있으나, $TiCl_4$를 응집제로 사용할 경우 생성된 슬러지를 인발하여 건조 및 소성을 통해 이산화티타늄으로 재활용할 수 있어 슬러지를 친환경적으로 처리가 가능해 기존 슬러지 처리방안의 경제적, 환경적 부담을 줄일 수 있는 장점이 있다. 따라서 본 연구에서는 $TiCl_4$를 하수처리장 방류수에 주입하여 수중의 총인(T-P)을 처리한 후 생성된 슬러지를 인발하여 건조와 소성과정을 거쳐 이산화티타늄을 제조하였다. 방류수를 취수해 2.5mg/L의 초기 총인 농도를 가진 원수를 제조하였으며 제조된 원수에 $TiCl_4$를 0.6mL 주입하였을 때 99.93%의 총인제거효율을 얻을 수 있었다. 응집 실험 후 생성된 슬러지를 인발하여 건조 후 $300{\sim}1000^{\circ}C$의 각각 다른 온도조건에서 소성하여 이산화티타늄을 제조하였으며, SEM과 XRD를 통해 제조된 이산화티타늄의 표면특성과 결정성 분석을 실시하였다. 제조된 이산화티타늄은 $500{\sim}800^{\circ}C$에서는 아나타제, $900{\sim}1000^{\circ}C$에서는 루타일 결정구조가 나타났다. 또한, $TiCl_4$ 주입량에 따른 이산화티타늄의 최종 생산량과 제조 시 사용되는 건조로 및 소성로의 경제적 비용 등을 고려하여 이산화티타늄 1Ton을 제조하기 위해 필요한 단가를 산출하였다. 본 연구에서 제조된 이산화티타늄 1kg의 생산단가는 약 5,400원으로 나타났으며, 가장 많이 사용되는 P-25 광촉매 보다 저렴한 가격으로 제조 및 판매를 기대할 수 있다. 따라서 하수처리장에 적용 시 기존 응집제 보다 비싼 $TiCl_4$ 비용을 보완하고 친환경적인 슬러지 처리로 제조된 이산화티타늄의 유통 및 현장적용을 통해 경제적, 환경적으로 우수하다고 판단된다.

• Korean Journal of Optics and Photonics
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• v.12 no.2
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• pp.135-142
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• 2001

Recently, plastic optical fiber draws a lot of attention as a new transmission medium for local area network (LAN) and home network applications. As PMMA based GI-POF (Graded Index Plastic Optical Fiber) has very low loss at about 500 nm and 650 nm wavelengths, it is very important to have a compact ultra short optical pulse source at these wavelength windows. In this paper, we have investigated detailed characteristics of gain switched laser system by using a commercially available low cost RF devices and an InGaAlP Fabry Perot semiconductor laser operating at 650 nm wavelength. The shortest optical 'pulse obtained was 33 psec with 1 GHz repetition rate. Depending on the DC bias current and the modulation frequency, the FWHM and the pulse energy of the gain switched pulses show 33.3-82.8 psec and 0.97-9.69 pI respectively. Also, the spectral bandwidths for CW and gain switched operations are 0.44 nm and 1.50 nm. We believe that these results are quite useful for high bit rate optical transmission applications with PMMA based plastic optical fibers in addition to estimate properties of ultra fast optical components and electro-optic devices. vices.

• Korean Journal of Heritage: History & Science
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• v.40
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• pp.413-430
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• 2007

This study analyzed the foreign substances in waterlogged archaeological woods and compounds in soil where waterlogged archaeological wood was buried, in order to examine the relationship between burial environment and foreign substances in waterlogged archaeological wood. The XRF(X-ray Fluorescence Spectroscopy) and EDX(Energy Dispersive X-ray) analysis were conducted to examine the effect of iron(Fe) to blacken the waterlogged wood. The XRF results showed that investigated soil contained Si, Al, and Fe. Wood ash contained more sulfur and Fe than any other elements in the EDX analysis. Cellulose and hemicellulose were significantly reduced at the surface of wood, which is the blackened part of waterlogged wood. Foreign substances changed the surface color. These problems could be solved by removal of foreign substances in waterlogged archaeological wood using EDTA(Ethylene Diamine Tetra Acetic acid). The optimum condition to remove Fe from waterlogged wood by EDTA was investigated. To do this, the concentration of Fe removed was measured with various concentration of EDTA-2Na. The optimum pH of EDTA-2Na was figured to be 4.1 to 4.3. As the concentration of EDTA increased, the extracted concentration of Fe also increased. In the case of 0.4 wt% of EDTA-2Na, about 60ppm of Fe was eliminated and was stabilized after 48 hours. In the case of EDTA-3Na, the optimum pH was 7 to 8, and about 10 ppm of Fe was eliminated at 0.4 wt% of EDTA-3Na. In the case of EDTA-4Na, the optimum pH was 10 to 11, and about 20 ppm of Fe was eliminated at 0.4 wt% of EDTA-4Na. In conclusion, the iron(Fe) in waterlogged archaeological wood was removed by EDTA treatment and it increased the whiteness of the surface.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.4
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• pp.263-275
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• 2022

There is a paucity of detailed data related to the effect of senescence on the mitochondrial antioxidant capacity and redox state of senescent human cells. Activities of TCA cycle enzymes, respiratory chain complexes, hydrogen peroxide (H₂O₂), superoxide anions (SA), lipid peroxides (LPO), protein carbonyl content (PCC), thioredoxin reductase 2 (TrxR2), superoxide dismutase 2 (SOD2), glutathione peroxidase 1 (GPx1), glutathione reductase (GR), reduced glutathione (GSH), and oxidized glutathione (GSSG), along with levels of nicotinamide cofactors and ATP content were measured in young and senescent human foreskin fibroblasts. Primary and senescent cultures were biochemically identified by monitoring the augmented cellular activities of key glycolytic enzymes including phosphofructokinase, lactate dehydrogenase, and glycogen phosphorylase, and accumulation of H₂O₂, SA, LPO, PCC, and GSSG. Citrate synthase, aconitase, α-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, isocitrate dehydrogenase, and complex I-III, II-III, and IV activities were significantly diminished in P25 and P35 cells compared to P5 cells. This was accompanied by significant accumulation of mitochondrial H₂O₂, SA, LPO, and PCC, along with increased transcriptional and enzymatic activities of TrxR2, SOD2, GPx1, and GR. Notably, the GSH/GSSG ratio was significantly reduced whereas NAD⁺/NADH and NADP⁺/NADPH ratios were significantly elevated. Metabolic exhaustion was also evident in senescent cells underscored by the severely diminished ATP/ADP ratio. Profound oxidative stress may contribute, at least in part, to senescence pointing at a potential protective role of antioxidants in aging-associated disease.

• Journal of Dental Anesthesia and Pain Medicine
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• v.22 no.5
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• pp.323-338
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• 2022

Burning mouth syndrome (BMS) is a chronic oral disorder of unknown etiology which presents therapeutic challenges. Alpha-lipoic acid (ALA) has been studied as a potential treatment for BMS. The objective of this systematic review and meta-analysis was to evaluate the effectiveness of ALA compared to that of placebo or other interventions in individuals with BMS. Randomized controlled trials (RCT) using ALA to treat BMS were identified from MEDLINE, Cochrane Library, EMBASE, and Web of Science up to February 3, 2021. The assessment of the risk of bias in the included studies was based on the Cochrane guidelines. The primary outcome evaluated was the visual analog scale (VAS) pain intensity. ALA was compared with placebo, clonazepam, gabapentin, pregabalin, ALA plus gabapentin, capsaicin, Biotène^®, and laser therapy. Altogether, 137 records were scanned for inclusion/exclusion, and nine RCTs (two unclear and seven at high risk of bias) were included in the qualitative and quantitative analyses, with a total of 594 patients with BMS included in this review. All studies reported an improvement in VAS pain scores ranging from -0.72 to -2.77. Meta-analysis results showed a non-significant reduction in pain intensity for ALA (P = 0.616) compared to that of placebo on a VAS of 0-10. Patients taking ALA were 1.923 times more likely to show an improvement in self-reported BMS symptoms (P = 0.031) than those in the placebo group. Clonazepam and pregabalin showed a significant VAS pain reduction of 4.08 and 4.68 (P < 0.001), respectively, compared to that with ALA. Although ALA intervention provided a non-significant improvement in the pain score and was more likely to produce a reduction in BMS symptoms, the evidence was of low quality. Further research is needed to establish clear guidelines for the use of ALA for BMS treatment.

• Journal of Conservation Science
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• v.38 no.4
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• pp.289-300
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• 2022

In the 6^th and 7^th centuries, 5 iron artifacts excavated form the Baekje Stone Tomb in Guryong-ri site, Ungcheon, Boryeong, were studied. The sample were metal microscopic observation, SEM-EDS analysis and Raman micro-spectroscopy analysis were conducted to understand the metallurgical characteristics. The microstructure observation showed the presence of ferrite and pearlite throughout, and differences in carbon content existed depending on the direction. Non-metallic inclusions were in the form of long lines, and most of them were wüstite, fayalite. It is indicated that the artifacts were forge welded using hypoeutectoid steel, with signs of carburizing and decarburizing processes. Some crystals with high P₂O₅, TiO₂, CaO content were identified as sarcopside, ulvöspinel, and perovskite, respectively, through Raman spectroscopy. A comparison of the results with previous studies on the sites of Bujang-ri site in Seosan and Bongseon-ri site in Seocheon, which are adjacent sites in the coastal area, revealed that, while heat treatment technology was available, the artifacts were not heat-treated considering the purpose for use for these artifacts. The chemical composition of the non-metallic inclusions P₂O₅, TiO₂, CaO were plotted in proportions to SiO₂ and compared with adjacent sites. Considering that the P₂O₅/SiO₂ ratio was widely distributed, the refining technology was not uniform. In addition, the TiO₂/SiO₂ ratio was found to be higher than that of other sites, meaning that a titanium-containing ore was used to manufacture the artifacts, unlike in surrounding sites, but it is not detected in all artifacts, so it may have been affected by various factors such as furnace walls in addition to raw materials. Although slag formers were used, considering the CaO/SiO₂ ratio and the (Al₂O₃/SiO₂)/(CaO/SiO₂) ratio, which appear to be similar to the surrounding sites, but it is possible that CaO containing raw ore was used because it is also affected by the components of raw ore. As a result of the study, it is highly likely that ore different from that of the surrounding sites was used for production, but a more comprehensive comparative study with the surrounding sites is needed in the future.