• Journal of the Korean Ceramic Society
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• v.44 no.6 s.301
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• pp.325-330
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• 2007

High porous AlO(OH) gel is used in precursor of ceramic material, coating material and porous catalyst. For use of these, not only physiochemical control for particle morphology, pore characteristic and peptization but also studies of synthetic method for preparation of high porous AlO(OH) gel were required. In this study, high porous AlO(OH) gel was prepared through the aging and filtration process of aluminum hydroxides gel precipitated by the hydrolysis reaction of $Na_2CO_3$ solution and $Al_2(SO_4)_3$ and $Na_2SO_4$ mixed solution. In this process, optimum synthetic condition of AlO(OH) gel having excellent pore volume as studying the effect of hydrolysis pH on gel precipitates has been studied. Hydrolysis pH brought about numerous changes on crystal morphology, surface area, pore volume and pore size. Physiochemical properties of gel were investigated as using XRD, TEM, TG/DTA, FT-IR and $N_2$ BET method.

• The Korean Journal of Zoology
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• v.36 no.1
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• pp.97-108
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• 1993

The biochemical characteristics of immunorecative atrial natriuretic peptide (irAUPP and the changes in the levels of irANP in the heart were investigated during the metamorphosis of frog tadpoles. Immunohistochemical localization of pro-ANP in cardiocfes and the presence of irAW in the peritoneal fluid of metamorphosing tadpoles were also examined. The major form of irANP in the cardiocvtes of tadpoles (Rana omurensisp was high molecular weight on gel filtration chromatographv and reverse-phase HPLC. The levels of irANP in the atrium of tadpoles were five to seven times higher than those in the ventricle. In metamorphosing tadpoles the levels of irANP in the atrium increased at stage XX, the climax of metamorphosis, and decreased at stage XXV (P < 0.051, the completion of metamorphosis. When the levels of irANP was expressed as a function of body weight of tadpoles, a continuous increase in the levels of irANP was observed from pre- to postmetamorphosis (P < 0.051. The levels of irAUP in the ventricle were found to be higher in the adult frogs than in tadpoles (R. omurensisl (P < 0.01). Pro-ANP (31-67) immunoreactivity was detected in the ventricle as well as in the atrium of tadpoles fR. nigromaculotal. The peritoneal fluid was also found to contain low molecular weight of irAUP and the levmils of irANP were 55.4 $\pm$ 9.1 pg/ml. Changes of the level of irANP at different stases of the life cycle suggest that ANP may play a role in the regulation of body fluid homeostasis of frog tadpoles during the metamorphosis.

• Journal of Microbiology and Biotechnology
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• v.7 no.2
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• pp.107-113
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• 1997

A strain producing a high amount of chitinase was isolated from soil, identified as Pseudomonas sp., and tentatively named Pseudomonas sp. YHS-A2. An extracellular chitinase of Pseudomonas sp. YHS-A2 was purified according to the procedure of ammonium sulfate saturation, affinity adsorption, Sephadex G-100 gel filtration and Phenyl-sepharose CL-4B hydrophobic interaction column chromatography. The molecular weight of the purified enzyme was estimated to be 55 kDa on SDS-PAGE was confirmed by active staining. Optimal pH and temperature of the enzyme are pH 7.0 and $50^{\circ}C$, respectively, and the enzyme is stable between pH 5.0 and 8.0 and below $50^{\circ}C$. The main products of colloidal chitin by the chitinase were N-acetyl-D-glucosamine and N,N'-diacetylchitobiose both of which were detected by HPLC analysis. The enzyme is supposed to be a random-type endochitinase which can degrade any position of ${\beta}$-l,4-linkages of chitin and chitooligosaccharides. The chitinase inhibited the growth of some phytopathogenic fungi, Fusarium oxysporum, Botrytis cineria, and Mucor rouxii and these antifungal effects were thought to be due to the characteristics of endochitinase.

• Environmental Engineering Research
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• v.17 no.4
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• pp.185-190
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• 2012

Rejection characteristics of perchlorate ($ClO_4^-$) were examined for commercially available reverse osmosis (RO) and nanofiltration (NF) membranes. A bench-scale dead-end stirred-cell filtration system was employed to determine the toxic ion rejection and the membrane flux. Model water solutions were used to prepare $ClO_4^-$ solutions (approximately, $1,000{\mu}g/L$) in the presence of background salts (NaCl, $Na_2SO_4$, and $CaCl_2$) at various pH values (3.5, 7, and 9.5) and solution ionic strengths (0.001, 0.01, and 0.01 M NaCl) in the presence of natural organic matter (NOM). Rejection by the membranes increased with increasing solution pH owing to increasingly negative membrane charge. In addition, the rejection of the target ion by the membranes increased with increasing solution ionic strength. The rejection of $ClO_4^-$ was consistently higher for the RO membrane than for the NF membrane and $ClO_4^-$ rejection followed the order $CaCl_2$ < NaCl < $Na_2SO_4$ at conditions of constant pH and ionic strength for both the RO and NF membranes. The possible influence of NOM on $ClO_4^-$ rejection by the membranes was also explored.

• Analytical Science and Technology
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• v.28 no.4
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• pp.270-277
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• 2015

Boiling point (BP) is one of the most fundamental physicochemical properties of organic compounds to characterize and identify the thermal characteristics of target compounds. Previously developed QSPR equations, however, still had some limitation for the specific compounds, like high-energy molecules, mainly because of the lack of experimental data and less coverage. A large BP dataset of 5,923 solid organic compounds was finally secured in this study, after dedicated pre-filtration of experimental data from different sources, mostly consisting of compounds not only from common organic molecules but also from some specially used molecules, and those dataset was used to build the new BP prediction model. Various machine learning methods were performed for newly collected data based on meaningful 2D descriptor set. Results of combined check showed acceptable validity and robustness of our models, and consensus approaches of each model were also performed. Applicability domain of BP prediction model was shown based on descriptor of training set.

• Childhood Kidney Diseases
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• v.24 no.2
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• pp.107-114
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• 2020

Purpose: The purpose of this study was to evaluate the prevalence, clinical characteristics, and long-term clinical effects of hypertension in Korean childhood-onset systemic lupus erythematous (SLE) patients. Methods: The medical records of SLE patients, diagnosed by 2019 SLE European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria, who visited Samsung Medical Center from January 2009 to May 2019 were reviewed. Disease activity and long-term damage were evaluated using the Modified Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) and the Pediatric Systemic Lupus International Collaborating Clinics/ACR Damage Index (Ped-SDI), respectively. The sex-, age- and height-blood pressure standards recommended by the American Academy of Pediatrics 2017 guideline was used to define hypertension. Results: A total of 32 patients were enrolled in this study. The median follow-up duration was 7.3 years and females were predominant. The median ages at SLE and hypertension diagnoses were 14.2 and 14.3 years, respectively. The biopsy-proven lupus nephritis was detected in 90.6% and 37.5% were class IV. During the follow-up, 12 patients (37.5%) had hypertension. Among them, 2 patients had 3 episodes of posterior reversible encephalopathy syndrome and 5 patients had left ventricular hypertrophy (LVH). Univariate analysis showed baseline hypertension was significantly correlated with a lower estimated glomerular filtration rate, higher body mass index and SLEDAI at baseline. The development of hypertension during the follow-up was significantly correlated with obesity, LVH, and higher Ped-SDI. Conclusion: Our study revealed that hypertension in pediatric SLE is associated with obesity and renal function at SLE diagnosis and could affect long-term damage.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.285-285
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• 2017

최근 전 세계적으로 심각해지는 물 부족 현상과 수질오염으로 대량의 원수를 빠른 시간 내에 여과하기 위한 여과장치의 개발 및 효율성 향상을 위한 연구의 필요성이 증가되고 있다. 특히 여과필터의 내부구조에 의해 유동이 편중되는 현상이 발생하면 여과효율 및 여과필터 유지관리에 문제가 발생되기 때문에 최적의 여과필터를 설계하는 것이 중요하다. 이에 본 연구에서는 수리모형실험으로 검토하기에 어려움이 있는 여과기 내부구조에 대한 유동특성을 수치해석을 이용하여 검토하였다. 수치해석은 유한요소법 기반의 수치모형으로 여과기 내부를 상세하게 모의할 수 없기 때문에 유한체적법 기반인 ANSYS CFX 모형을 이용하였다. 여과기 내 여과필터는 두께 2.0 mm, 공극율 25%로 가정하고 다공성 기법(porous media)을 적용하였다. 검토를 위한 경계조건은 유입부에 목표 취수량, 유출부에 대기압 조건을 적용하였으며, 여과기에 비해 매우 작게 구성된 여과필터 내부의 유동특성을 검토하기 위해 여과기는 최소 3.0 mm, 여과필터는 1.0 mm의 격자를 적용하였다. 현재 실제 여과시설에 적용되고 있는 여과기 제품 형상을 기준으로 여과기 내부 흐름공간의 크기 및 각도 조정에 따른 유동특성을 검토하여 여과효율을 비교하였으며 통과유량, 유속, 유속벡터 등을 검토하여 균등한 유량과 유속이 발생되는 최적의 여과장치 구조를 도출하였다. 본 연구에서 여과기 내부 구조 변경에 따른 유동특성 검토를 통해 도출된 최적의 여과기 내부크기 및 각도에 대한 설계인자는 여과기 내 여과필터의 효율을 증가시킬 뿐만 아니라 내구성 증진에 도움이 될 것으로 예상된다.

• Membrane and Water Treatment
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• v.1 no.4
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• pp.283-296
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• 2010

During the disinfection of potable water, humic substances present in the solution react with chlorine to form potential carcinogenic compounds. This study evaluates the feasibility of using a submerged membrane photocatalysis reactor (SMPR) process for treatment of humic substances through the characterization of both organic removal efficiency and membrane hydraulic performance. A simple SMPR was operated and led to the removal of up to 83% of the polluting humic matters. Temporal rates of organic removal and membrane fouling were found to decrease with filtration time. Using tighter membrane in the hybrid process resulted in not only higher organic removal, but also more significant membrane fouling. Under the experimental conditions tested, optimum $TiO_2$ concentration for humic removal was found to be 0.6 g/L, and increasing initial pollutant concentration expectedly resulted in a more substantial membrane fouling. The importance of the influent nature and pollutant characteristics in this type of treatment was also assessed as various water sources were tested (model humic acid solution vs. local water containing natural organic matters). Results from this study revealed the promising nature of the SMPR process as an alternative technique for organic removal in the existing water treatment system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.4
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• pp.320-326
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• 2019

Recently, the application of atmospheric plasma technology in air filtration is increasing. Sterilization by an atmospheric plasma device is very effective. However, ozone gas, which is generated during atmospheric plasma formation, poses a hazard to human health. To reduce the ozone gas during plasma discharge, we fabricated a one-plate hybrid plasma discharge device with a heating element, which can decompose ozone gas effectively by a simple heating action. In this study, we evaluated the plasma discharge characteristics and ozone concentrations with various Ar flow rates and temperatures. With increasing Ar gas flow rate, the ozone concentration and spectrum intensity increased till an Ar gas flow rate of 60 sccm, and decreased thereafter. When discharged in high temperature, the ozone concentration and spectrum intensity decreased. Further, to evaluate the state of the treated surface under various plasma discharge and heating conditions, we measured the variation in the contact angles on the surface. Regardless of the temperature, the contact angle increased with increasing discharge voltage. However, the contact angle increased when discharged at high temperature.

• Journal of Pharmacopuncture
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• v.22 no.3
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• pp.140-146
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• 2019

Objectives: Venomous fishes have different pharmacological effects and are useful. Among the venomous fish, stonefishes; especially Pseudosynanceia melanostigma has various pharmacological effects on the nervous, muscular and cardiovascular system of humans. In this study, toxicological characteristics, some blood effects, pharmacological and enzymatic properties of Pseudosynanceia melanostigma venom was investigated. Methods: Crude venom purified by using gel filtration chromatography and the molecular weights of the venom and its fractions were estimated. The approximate LD values of this venom were determinedand the effects of LD50 dose on the blood of rabbits were studied. Hemolytic and Hemorrhagic activity of the venom sample was determined. In this case coagulation tests were performed. Results: The LD50 of the Pseudosynanceia melanostigma crude venom was also determined to be $194.54{\mu}g/mouse$. The effect of two doses of LD50 showed a non-significant differences decrease in RBCs and MCV. In other cases, the results showed significant differences in WBC, Plt, Hb, MCH, MCHC and HCT; also it's showed a significant decrease. WBC count showed a significant increase with two doses of LD50 groups. The prothrombin time and partial prothrombin time were increased after venom treatment. As well as bleeding and clotting time were increased. According to the results, a minimum dose for Haemorrhagic effect $40{\mu}g$ was obtained. Conclusion: Venom of Pseudosynanceia melanostigma has inhibitory effect on platelet aggregation that can be used to design and develop of anticoagulant drugs.