• Archives of Pharmacal Research
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• 제18권5호
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• pp.346-350
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• 1995

To assess the behavior of the various chemicals, such as ethylcholine axiridinium (AF54A), scopolamine and morphine, the chemicals were administered into eitheer rat or mice. And water maze tests were performed before and during drug administration. In AF64A-treated groups (3 nmol/each ventricle), the latencies to escape was significantly increased in both of the pretraining-and posttraining groups. In scopolamine-treatment (2mg/kg, sc) to the pretrained group, the latency to escape was significantly shortened after the acute administration of scopolamine. However in subscute treatment group with scopolamine, the latency to escape was significantly increased. In morphine-treated groups (10 mg/kg, ip), the subacute treatmment with morphine, the latency to escape was not ahcnged. The results indicate that each chemical induces the learning impariment. However the chrmical-induced learning impairment may have different characteristics upon the exposed chemical. Also the results suggest that both the motivation and the retrieval of memory might be impaired by AF64A.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.605-609
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• 2014

Magnetic multi-granule nanoclusters (MGNCs) were investigated as an inexpensive means to effectively remove arsenic from aqueous environment, particularly groundwater sources consumed by humans. Various size MGNCs were examined to determine both their capacity and efficiency for arsenic adsorption for different initial arsenic concentrations. The MGNCs showed highly efficient arsenic adsorption characteristics, thereby meeting the allowable safety limit of $10{\mu}g/L$ (ppb), prescribed by the World Health Organization (WHO), and confirming that 0.4 g and 0.6 g of MGNCs were sufficient to remove 0.5 mg/L and 1.0 mg/L of arsenate ($AsO_4{^{3-}}$) from water, respectively. Adsorption isotherm models for the MGNCs were used to estimate the adsorption parameters. They showed similar parameters for both the Langmuir and Sips models, confirming that the adsorption process in this work was active at a region of low arsenic concentration. The actual efficiency of arsenate removal was then tested against 1 L of artificial arsenic-contaminated groundwater with an arsenic concentration of 0.6 mg/L in the presence of competing ions. In this case, only 1.0 g of 100 nm MGNCs was sufficient to reduce the arsenic concentrations to below the WHO permissible safety limit for drinking water, without adjusting the pH or temperature, which is highly advantageous for practical field applications.

• KSBB Journal
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• 제13권2호
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• pp.209-213
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• 1998

The characteristics of de-emulsification of pertroleum emulsion by Nocardia amarae were investigated. Insoluble medium containing n-hexadecane was more effective than soluble medium in de-emulsification of emulsion containing diesel and bunker C as the organic phase. Emulsion made by the addition of xanthan or bioemulsifier was de-emulsified by N. amarae, and longer culture age was effective. In low viscosity range, organic phase with longer carbon chain was more effective. The contact, angle between bacterial film and water droplet in air increased from 16 degree for 4 day culture age to 26 degree for 15 day. The contact angle between bacterial film and water droplet in kerosene, n-heyxane or n-hexadecane also increased to greater than 100 degree after 3 day culture age. The hydrophobicity of bactgerial film increased according to the culture age.

• 대한화학회지
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• 제60권4호
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• pp.261-266
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• 2016

The major physical characteristics of macromolecules used in silicone hydrogel ophthalmic lenses include optical transmittance, oxygen permeability, water content, and refractive index. For the preparation of highly functional silicone hydrogel lens materials, two silicone monomers were used in the presence of 2-hydroxyethyl methacrylate (HEMA) and hydroxypropyl methacrylate (HPMA). The samples containing HEMA and HPMA had oxygen transmissibility (Dk) values in the range of 73.38–50.98 × 10^-11 (cm²/s) (mLO₂/mL×mmHg) and 71.94–42.80 × 10^-11 (cm²/s) (mLO₂/mL×mmHg), respectively. Furthermore, the water contents of samples containing HEMA and HPMA were in the range of 32.73–34.67% and 31.94–33.74%, respectively, and the refractive indices were in the range of 1.4348–1.4364 and 1.4385–1.4407, respectively. Thus, silicone monomers containing HEMA and HPMA are expected to be useful for fabricating high-oxygen-permeability silicon hydrogel ophthalmic lenses.

• Bulletin of the Korean Chemical Society
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• 제30권4호
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• pp.887-890
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• 2009

Hydroxyapatite (HAp)-based materials have attracted considerable attention on account of their excellent stability and recrystallization. Nanoscale HAp powders with a mean particle size of 200 nm were used to regenerate the enamel layers of damaged teeth. An artificially scratched tooth was immersed in a nanoscale HAp powder suspension in d.i. water (HAp of 70 wt%) at 37 ${^{\circ}C}$ for a period of 1~3 months. SEM and AFM showed that the scratched surface was ultimately inlaid with HAp after three months and the roughness increased from 2.80 to 5.51. Moreover, the hardness of the neo-generated HAp layer on the crown was similar to that of the innate layer. $Ca^{2+}$ and ${PO_4}^{3-}$ ions from the HAp powders dissolved in d.i. water were precipitated on the tooth to produce cemented pasteson the enamel surface due to its high recrystallizing characteristics, resulting in a hard neo-regenerated HAp layer on the enamel layer. This nanoscale HAp powder solution might be used to heal decayed teeth as well as to develop tooth whitening appliances.

• 웰빙융합연구
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• 제4권4호
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• pp.15-25
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• 2021

Purpose: The purpose of this study is to form a new cosmetic market through the development of a composition with high skin permeability after adding omega 3 to Aloe Vera soothing gel products. Research design, data and methodology: In this study, omega-3 fatty acids were added to cosmetic products in the form of soothing gels. By applying nanoparticle technology to rapidly increase the penetration of raw materials into the skin, characteristics related to skin moisture and regeneration were determined. Omega-3 was used as a raw cosmetic material. Then 5% and 15% nanoparticle aqueous products containing omega-3 were prepared. The developed water hydrate was subjected to skin permeability test using artificial skin. Results: 53 hours of artificial transdermal penetration of the developed composition, the ethanol-based omega-3 containing nanoparticle solubilized raw material was about three times higher penetration than the ethanol-based omega-3 containing nanoparticle solubilized raw material. Conclusions: The raw material product (SR-1901) containing 5% of omega-3 nanoparticle water hydrate has skin regeneration ability and pain reduction effect. It can be expected that the skin cosmetics market will be reorganized into a new distribution structure and opportunity through omega-3 supplemented soothing gel cosmetics with improved efficacy than existing cosmetics.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.52-58
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• 2019

Marine emissions of Volatile Organic Compounds (VOCs) have received much attention because the International Maritime Organization (IMO) requires the installation of vapour emission control systems for the loading of crude oils or petroleum products onto ships. It was recently recognised that significant corrosion occurs inside these vapour emission control systems, which can cause severe clogging issues. In this study, we analysed the chemical composition of drain water sampled from currently operating systems to investigate the primary causes of corrosion in vapour recovery systems. Immersion and electrochemical tests were conducted under simulated conditions with various real drain water samples, and the impact of corrosion on the marine vapour recovery system was carefully investigated. Moreover, corrosion tests on alternative materials were conducted to begin identifying appropriate substitutes. Thermodynamic calculations showed the effects of environmental factors on the production of condensed sulphuric acid from VOC gas. A model of sulphuric acid formation and accumulation by the characteristics of VOC from crude oil and flue gas is suggested.

• Bulletin of the Korean Chemical Society
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• 제17권3호
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• pp.262-268
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• 1996

Flow properties of all suspensions are controlled by their flow units. The factors effecting on the flow units are the characteristics of the particle itself (surface properties, particle sizes, particle shapes and etc.), the electrostatic interactions among the particles and the influences of the medium in the suspensions. Here, we studied the transition between the flow units with shear rate which can be added to the above factors. For the concentrated starch-water suspensions, by using the Couette type rotational viscometer, we confirmed that at low shear rate, dilatancy is appeared, but it is transformed to thixotropy with increasing shear rate. In order to explain this fact, we derived the following flow equation, representing the transition from dilatancy to thixotropy with shear rate, by assuming the equilibrium between the flow units. f = X1β1s./α1 + 1/(1+Kexp(c0s.2/RT))((1-X1)/α2)sinh-1{(β2)0 s. exp(c2s.2/RT)} + K exp(c0s.2/RT)/(1+K exp(c0s.2/RT))((1-X1)/α3)sinh-1{(β3)0 s. exp(-c3s.2/RT)} By applying this flow equation to the experimental flow curves for the concentrated starch-water suspensions, the flow parameters were obtained. And, by substituting the obtained flow parameters to the flow equation, the theoretical flow curves were reproduced. Also, Ostwald curve was represented by applying the flow equation, and the applicability for stress relaxation was discussed.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권1호
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• pp.60-70
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• 2022

We evaluated the performance of in-situ capping to prevent the release of phenol, one of hazardous chemicals of concern for their impact on sediment. Sediment near the estuary of Hyeongsan River, Korea, and commercially-available sand were collected to evaluate their physical properties and phenol sorption characteristics. Biodegradation kinetics of phenol spiked into the sediment was evaluated under freshwater and estuarine salinity conditions. These experimental measurements were parameterized and used as input parameters for executing CapSim, a software predicting the performance of in-situ capping. The CapSim simulation demonstrated that capping with 50-cm sand reduced the phenol release by several orders of magnitude over 0.25- and 1-year duration for almost all simulation scenarios. The variables tested, i.e., cap thickness, pore-water movement, and biodegradation rate, showed high correlation to each other to influence the extent of phenol release from sediment to the water column. The findings and the framework employed to evaluate the performance of in-situ capping in this study can be adopted to determine whether in-situ capping is appropriate remedial approach at sediment sites impacted by hazardous chemicals due to accidental spills.

• 한국축산식품학회지
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• 제26권3호
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• pp.337-342
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• 2006

본시험은 돼지에 대한 산삼 배양액 급여 효과를 구명하기 위하여 $60{\pm}3kg(126{\pm}3$일령)의 Berkshire 종 암퇘지와 거세돼지 각각 60두씩 총 120두를 선발하여 2(성; 암 vs. 거세)${\times}2$(대조구 vs. 산삼 배양액 첨가구) 'factorial' 실험설계 하에 돈방당 30두씩 4 돈방에 임의로 배치한 다음 약 110 kg($193{\pm}4$일령)까지 70일간 비육 시험을 수행하였다. 이때 대조구는 산삼 배양액을 첨가하지 않은 구로 하였고, 시험구는 산삼 배양액을 1일 1L씩 첨가 음수시켰고, 그 결과는 다음과 같다. 처리 간에 암퇘지의 경우 수분 함량, 경도 및 씹힘성은 대조구보다 처리구가 높게 나타났으나, 보수력과 지방의 $L^*$값은 반대로 낮게 나타났다(p<0.05). 처리 간에 거세돼지의 경우 전단가와 육색 $a^*$값이 대조구보다 처리구가 높게 나타나(p<0.05) 산삼 배양액 급여에 따라 조직이 단단해지고 육의 $a^*$값은 향상되나 보수력과 지방의 명도가 낮아지는 단점을 나타내었다. 성별 간에 처리구의 경우 조지방 함량, 지방의 $a^*$와 $b^*$값, 경도, 응집성 및 씹힘성은 암퇘지보다 거세돼지가 낮게 나타났으나, pH는 반대로 높게 나타나(p<0.05) 암퇘지에 비하여 거세돼지가 조지방 함량은 적고, 조직이 무르나 지방의 $b^*$값은 낮고 pH가 높은 장점을 나타내었다.