• Bulletin of the Korean Chemical Society
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• v.13 no.5
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• pp.479-482
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• 1992

Several poly(alkyl methacrylate-b-t-butyl methacrylate) diblock copolymers were synthesized by group transfer polymerization. The molecular weight of poly(t-butyl methacrylate) segments and the composition of the resulting block copolymers were controlled by the monomer feed ratios and mole ratios of monomer to initiator. The poly(t-butyl methacrylate) block was quantitatively hydrolyzed to poly(methacrylic acid) block by refluxing with a catalytic amount of p-toluenesulfonic acid in dioxane at $100^{\circ}C$ for 12 hrs. The thermogravimetric analysis of poly(alkyl methacrylate-b-t-butyl methacrylate) exhibited the lose of isobutylene and subsequent anhydride formation in the range of $205-300^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.18 no.6
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• pp.623-628
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• 1997

A layered perovskite oxide, $RbLa_2Ti_2NbO_{10}$, was prepared and investigated for proton exchange and intercalation behaviors. Its protonated form, $Hla_2Ti_2NbO_{10}$, exhibits the Bronsted acidity and reacts with organic amines. Polyoxonuclear cation, 4Al_{13}$, was then introduced into the interlayer by refluxing octylamine-intercalated compound with an $Al_{13}$ pillaring solution. These layered oxides were characterized by X-ray diffractometer, thermogravimeter, FT-infrared spectrometer and elemental analyzer. It is observed that the polyoxonuclear cation-pillared material exhibits a bilayer structure and is thermally more stable than organic counterpart at higher temperatures. The surface area of the pillared material annealed at 400 ℃ was the value of 25.1 m²/g.

• Elastomers and Composites
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• v.54 no.3
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• pp.252-256
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• 2019

Fullerene oxide[$C_{60}(O)_n$, ($n{\geq}1$)] was synthesized by dissolving fullerene[$C_{60}$] and 3-chloroperoxybenzoic acid in toluene under refluxing condition for 5 h. Hybrid fullerene oxide-silver nanoparticle composites were synthesized by dissolving fullerene oxide and silver nitrate[$AgNO_3$] in diethylene glycol under ultrasonic irradiation for 3 h. The synthesized hybrid nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, and ultraviolet-visible[UV-vis] spectroscopy. The catalytic activity for the reduction of various nitroanilines[NAs] was identified by UV-vis spectrophotometer. The efficiency of the catalytic reduction by the synthesized hybrid nanocomposites has an order of 4-NA > 2-NA > 3-NA.

• Elastomers and Composites
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• v.54 no.2
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• pp.105-109
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• 2019

Gold nanoparticles were synthesized by reacting potassium tetrachloroaurate ($KAuCl_4$), potassium carbonate ($K_2CO_3$), and isopropyl alcohol in the presence of fullerene oxide [$C_{60}(O)_n$, $n{\geq}1$], which was, in turn, prepared from [$C_{60}$] fullerene and m-chloroperoxybenzoic acid under refluxing conditions. The crystallinity and morphology of the prepared gold nanoparticles were confirmed by UV-vis spectroscopy, X-ray diffraction, and scanning electron microscopy. The activity of the gold nanoparticles in the reduction of 4-nitroaniline was measured in order to determine its capability as a catalyst.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.241.2-241.2
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• 2003

We report the synthesis of key intermediates for the development novel flavonoid derivatives with potential antiinflammatory activity and propose a mechanism of the one-pot reaction. The various amines (1) for this work were commercially available. Secondary amines (2) were formed by nucleophilic attraction using ethyl benzoylacetate. The C-N bond formation proceeded at refluxing in toluene with catalytic amount of p-toluenesulfonic acid and a removal of water was important in this reaction. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.183.2-183.2
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• 2003

We report the synthesis of 3,4-dihydro-2-oxo-4-quinolines 5a-e for the development novel flavonoid derivatives with potential antiinflammatory activity and propose a mechanism of the one-pot reaction. The various amines (la-e) for this work were commercially available. We isolated that ester (2a-e) were formed by nucleophilic attraction using ethyl benzoylacetate. The C-N bond formation proceeded at refluxing in toluene with catalytic amount of p-toluenesulfonic acid and a removal of water and ethanol was important in this reaction. (omitted)

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.227-227
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• 2006

It was attempted to synthesize polyimides from PPMDA and 3FPPMDA with mDAPPO/pPDA in order to afford CTE of 17ppm and adhesion property of 80g/mm, besides high Tg (>$300^{\circ}C$), good thermal stability (>$500^{\circ}C$), low water absorption and good solubility. The polyimides were prepared via a conventional two-step process; preparation of poly(amic-acid), followed by solution imidization by refluxing in NMP with o-DCB and the molar ratio of mDAPPO/pPDA was varied. The polyimides were characterized by FT-IR, NMR, DSC and TGA. In addition, intrinsic viscosity, solubility and coefficient of thermal expansion (CTE) were also measured.

• Childhood Kidney Diseases
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• v.28 no.1
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• pp.1-7
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• 2024

Antenatally diagnosed urinary tract dilatation (UTD), previously referred to as antenatal hydronephrosis, is the most commonly detected abnormality by prenatal ultrasonography. Several grading systems have been developed for the classification of antenatal UTD using prenatal and postnatal ultrasonography. UTD comprises a wide variety of congenital abnormalities of the kidney and urinary tract ranging from transient UTD to more significant abnormalities such as vesicoureteral reflux, ureteropelvic junction obstruction, ureterocele, ureterovesical junction obstruction, posterior urethral valves, and non-refluxing megaureter. Optimizing the evaluation of antenatally detected UTD is essential to recognize children with important disorders while avoiding excessive investigations. Conservative approach with close follow-up is increasingly accepted as an appropriate treatment option for patients with asymptomatic vesicoureteral reflux and ureteropelvic junction obstruction in recent years. However, predicting permanent kidney damage in an unselected group of children with antenatal UTD is still challenging. The management and follow-up of children with UTD should be individualized based on recommendations from a pediatric nephrologist, a pediatric urologist, or both. Future research directed at predicting long-term outcomes of children diagnosed with UTD from mild findings to severe disease is needed to refine management for those at higher risk of kidney disease progression.

• Childhood Kidney Diseases
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• v.2 no.2
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• pp.152-160
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• 1998

Purpose : Vesicoureteral reflux (VUR), which can result in renal failure in children, is expected to resolve spontaneously in mild cases, but severe cases require surgical correction, posing dilemma in deciding the right measures in some cases. Therefore, to delineate the factors affecting spontaneous resolution of VUR and to apply them in assessing the prognosis, we reviewed the patients with VUR who had been treated medically. Patients and Methods : 32 children (49 renal units) with reflux who had been admitted during the 5-year period from Jan '92 to Dec '96 were classified into 4 groups (Resolved, Improved, Unchanged, and Worsened) and analyzed. Results : 1) 25 were boys and 7 girls. The age at diagnosis ranged from 13 days to 9 years (mean $24.6{\pm}11.4$ mo) 2) Among 49 refluxing ureters, 4 were below 1 me of age,21 between 1 me to 1 yr, 16 between 1 yr to 6 yr, 8 beyond 6 yr. Two belonged to Grade I, 16 to Crade II, 17 to Grade III, 12 to Grade IV, and 2 to Grade V. 3) Spontaneous resolution rates of reflux were 100, 81, 47, 8, 0$\%$ for each Grade, respectively. Resolution plus improvement rates in Grade III and IV were 71 and $50\%$, each. 4) Resolution rates in relation to the age at diagnosis were $100\%$ for below 1 mo, $48\%$ between 1 mo to 1 yr, $56\%$ between 1 to 6 yr, and $13\%$ beyond 6 yr. 5) Of 15 unilateral refluxing ureters, 14 ($93\%$) resulted in resolution. Of 34 bilateral refluxing ureters, 11 ($32\%$) resolved spontaneously 6) Resolution occurred within 1 year in 20 units of 24 renal units in regular follow-up. Conclusion: The lower the initial grade and the younger the patient, the sooner the reflux resolved. Resolution was better when VUR was unilateral than bilateral. Long-term regular follow-up is essential because even the cases falling in Grades III and IV have high rates of spontaneous resolution and improvement with medical treatment.

• Journal of the Mineralogical Society of Korea
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• v.21 no.3
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• pp.283-287
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• 2008

The imogolite synthesis wore performed by using tetraethoxysilane (TEOS) and aluminium-sec-butoxide (ASB) at < $100^{\circ}C$. A mixure of TEOS and ASB in a molar ratio of 1:2 was prepared under vigorous stirring and the experiments were performed under the hydrothemal refluxing condition. When the concentration of TEOS and ASB in solution was 0.5 M, a well-crystallized imogolite was synthesized, and the reflections wore shown at d = 22.4, $9.5\;\AA$ etc., after XRD analysis. DTA analysis shows 2 exothemal peaks at 68 and $249^{\circ}C$, suggesting the dehydration and the dehyroxylation reaction, respectively. The result of TG indicates 41% weight loss. And the weak and unsymmetrical peaks by the Si-O-Al stretching vibrations at 953 and $993cm^{-1}$ and by O-Si-O bending vibration at $562cm^{-1}$ were observed after IR analysis. The synthetic imogolite was fibrous and shows a spiders web like network structure.