• The Journal of Korean Medicine
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• v.45 no.1
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• pp.45-64
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• 2024

Objectives: This study is purposed to investigate the effect and safety of laser therapy for stroke patients by systematic review and meta-analysis of the randomized controlled trials (RCTs). Methods: RCTs on the treatment of laser therapy for stroke patients were selected among the literature published from January 2000 to June 2022 in twelve domestic and foreign databases. The quality of the literature was evaluated using the Cochrane's Risk of Bias tool and RevMan 5.4 was used for the synthesis of results. Results: Total 2,598 patients with stroke were finally selected from 18 RCTs. Meta-analysis showed that laser therapy was effective in significantly improving activities of daily living (MBI), motor function (effective rate), upper motor function (FMA-UE), shoulder pain related factors (CGRP, ET-1, BK). Overall, the risk of bias was uncertain or low in the quality assessment of the literature. Conclusions: Although it is unclear that laser therapy is more effective than sham laser, laser therapy might be more effective in improving symptoms than conventional rehabilitation alone. Furthermore, no serious adverse events were founded in laser therapy studies. However, the quality of the selected literature was generally low. Therefore, further studies with high methodological quality on laser therapy for stroke patients would be required in the future.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.678-683
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• 2012

Ceria is one of the most important catalytic materials which can be used in three-way catalysts, waste water treatment, petroleum refining, etc. So far, many methods have been studied to produce ceria nanoparticles. In this study, ceria nanoparticles were prepared via solvothermal synthesis using supercritical methanol in short reaction time using a batch reactor. The size of synthesized ceria nanoparticles in supercritical methanol is 6 nm without capping agent, which is smaller than that made in supercritical water at the same conditions of $400^{\circ}C$ and 30 MPa. Size difference results from density and critical point difference between water and methanol and slow reaction rate at the surface of ceria particles in supercritical methanol which reduces crystal growth rate. Several organic compounds were added to modify the surface of ceria nanoparticles, and in-situ surface modification was confirmed by FT-IR and TGA analysis. Surface modified ceria nanoparticles have excellent dispersibility in organic solvent. Size and shape of surface modified ceria particles can be controlled by adjusting molar ratio of modifier to precursor and selection of modifier.

• Journal of the Korean Applied Science and Technology
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• v.34 no.1
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• pp.50-57
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• 2017

Zinc oxide is, one of metal oxide semiconductor, harmless to human and environment-friendly. It has excellent chemical and thermal stability properties. Wurtzite-zinc oxide is a large band gap energy of 3.37 eV and high exciton binding energy of 60 meV. It can be applied to various fields, such as solar cells, degradation of the dye waste, the gas sensor. The photocatalytic activity of zinc oxide is varied according to the particle shape and change of crystallinity. Therefore, It is very important to specify the additives and the experimental variables. In this study, the zinc oxide were synthesized by using a microwave assisted hydrothermal synthesis. The precursor was used as the zinc nitrate, the pH value was controlled as 11 by NaOH. Surfactants are the ethanolamine, cetyltrimethylammonium bromide, sodium dodecyl sulfate, sorbitan monooleate was added by changing the concentration. The composite particles had the shape of a star-like, curcular cone, seed shape, flake-sphere. Physical and chemical properties of the obtained zinc oxide was characterized using x-ray diffractometer, field emission scanning electron microscopy, thermogravimetric analysis and optical properties was characterized using UV-visible spectroscopy, photoluminescence and raman spectroscopy.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.777-783
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• 1997

$TiO_2$ powders were synthesized via hydrolysis reaction of titanium n-propoxide in n-propanol solvent and the reaction rates were studied by use of UV-vis spectroscopic method. Concentration of water, reaction temperature, reaction time and acid-base effects of the solution were investigated to determine the optimum conditions for $TiO_2$ powder synthesis. The reaction were controlled to proceed to pseudo-first orders reaction in the presence of excess water in n-propanol solvent. The rate constants which varied with temperature and concentration of water were calculated by Guggenheim method. Reaction using $D_2O$ was also carried out to determine the catalytic character of water. $TiO_2$ powders were synthesized only in the neutral and basic solution and those were almost spheric forms having average particle size of $0.4-0.7{\mu}m$ diameter. Particle size decreased with increasing concentration of water and reaction temperature, however, increased with increasing reaction time. Associative $S_N2$ mechanism for the hydrolysis was proposed from the data of n-value in the transition state and thermodynamic parameter. $D_2O$ solvent isotope effect showed that $H_2O$ molecules reacted as nucleophilic catalysis.

• Applied Chemistry for Engineering
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• v.27 no.1
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• pp.16-20
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• 2016

In this work, we describe the synthesis and infrared light reflecting characteristics of $TiO_2$/mica hybrid composites. $TiO_2$/mica composite materials were obtained by the hydrolysis and condensation reaction of titanium isopropoxide in an aqueous solution of acetic acid in the presence of mica particles. Amorphous phase of $TiO_2$ on the surface of mica was converted to the crystalline rutile phase via anatase phase by heat treatment ($600-1000^{\circ}C$, 1-3 h) of $TiO_2$/mica composite materials, and the size of crystals was controlled by heat treatment conditions. Physicochemical properties of mica and $TiO_2$/mica composites were investigated using FE-SEM, ED-XRF, and PXRD. The solar reflectance of $TiO_2$/mica composites in the near IR region (780~2,500 nm) measured using a diffuse reflectance NIR spectrophotometer was 88.6%, which is rather higher than that of calcined pure mica (86.6%). Therefore, $TiO_2$/mica composites can be used as NIR light reflective pigments.

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.336-341
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• 2018

In general, the synthesis of poly(3-hexylthiophene)(P3HT)-based block copolymers requires at least a 4-5 step process. To control the molecular weight, molecular weight distribution, and block ratio, the reaction conversion and time should be monitored. In addition, the reaction scale usually limited to several mg to g was difficult to increase due to the limitations of living radical polymerizations. In this study, we synthesized P3HT-b-poly(4-vinylprydine) (P3HT-b-P4VP) with a final product quantity of > 19 g via a 2-step synthetic method with an anionic polymerization. In this method, the molecular weight and molecular weight distribution of P3HT-b-P4VP can be well controlled without monitoring the reaction conversion. We also studied physical properties of P3HT-b-P4VP depending on different solvent systems, which were investigated by UV-vis spectroscopy, atomic force microscopy, and ultraviolet photoelectron spectroscopy.

• Journal of the Korean Ceramic Society
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• v.40 no.12
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• pp.1202-1207
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• 2003

Using a recently developed Hybric Plasma-Particle Accelerating Impact Deposition (HP-PAID) process, synthesis of nanostructured silicon coatings has been investigated by injecting vapor-phase TEOS (tetraethosysilane, (C$_2$H$\_$5/O)$_4$Si) into an Ar hybrid plasma. The plasma jet with reactants was expanded through nozzle into a deposition chamber, with the pressure dropping from 700 to 10 torr. Ultrafine particles accelerated in the free jet downstream of the nozzle, deposited by an inertial impaction onto a temperature controlled substrate. By using this process, nanostructured amorphous silicon coatings with grain size smaller than 10 nm could be synthesized. These samples were annealed in an Ar and crystallized at 900$^{\circ}C$ for 30 min. TEM analysis showed that the annealed coatings were also composed of nanoparticles smaller than 10 nm, which showed a good consistency that the average grain size of 7 nm was also estimated from a peak shift of 2.39 cm$\^$-1/ and Full Width at Half Maximum (FWHM) 5.92 cm$\^$-1/ of Raman analysis. The noteworthy is that a strong PL peak at 398 nm was also obtained for this sample, which indicates that the deposited coatings also contained 3∼4 nm nanostructured grains.

• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.392-395
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• 2014

(2S,3S,4S)-3,4-Dihydroxyglutamic acid (DHGA), a biologically active ${\alpha},{\beta}$-dihydroxy-${\gamma}$-amino acid, was efficiently synthesized from a readily available D-serine derivative in 30% overall yield over 11 steps. The key stereoselective $OsO_4$-catalyzed dihydroxylation reaction controlled by an N-diphenylmethylene group on the amino group of ${\gamma}$-amino-${\alpha},{\beta}$-unsaturated (Z)-ester successfully introduced the diol moiety of the intermediate 5a in 86% with more than 10 : 1 diastereomeric ration. Then it was in turn successfully converted to the desired target compound, (2S,3S,4S)-3,4-DHGA, via simple oxidation and hydrolysis in a highly stereoselective manner and a higher yield than the previous syntheses. This result strongly supports that our synthetic methodology of stereoselective $OsO_4$-catalyzed dihydroxylation should be useful in stereoselctive synthesis of various bioactive compounds with an amino diol moiety.

• Microbiology and Biotechnology Letters
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• v.43 no.4
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• pp.357-366
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• 2015

Quorum sensing (QS) is involved in the process of cell-to-cell communication and as a gene regulatory mechanism, which has been implicated in bacterial pathogenicity. Bacteria use this QS system to control a variety of physiological processes. In this study, pomegranate (Punica granatum L.) peel extract (PPE) was first screened for its ability to inhibit QS in bio-reporter strains (Chromobacterium violaceum and C. violaceum CV026). Next, the ability of PPE to inhibit swimming motility and biofilm formation was examined in Y. enterocolitica. Additionally, changes in the expression of specific genes involved in the synthesis of the N-acylhomoserine lactones (AHLs; yenI and yenR) and in the flagellar regulon (fliA, fleB and flhDC) were evaluated by reverse transcription (RT)-PCR. The results show that PPE specifically inhibited and reduced QS-controlled violacein production by 78.5% in C. violaceum CV026, and decreased QS-associated biofilm formation and swimming motility in Y. enterocolitica without significantly affecting bacterial growth. These inhibitory effects were also associated with the down-regulation of gene expression involved in the synthesis of AHLs and in motility. Our results suggest that PPE could be a potential therapeutic agent to prevent enteropathogens in humans, as well as highlight the need to further investigate the in vivo properties of PPE for clinical applications.

• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.328-333
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• 2014

Folate is a water-soluble vitamin B that is required for the synthesis of amino acids and nucleic acids. It plays an important role in cell division and cell growth in several living organisms. The purpose of this study was to screen strong folate-synthesizing bacteria and to optimize their culture conditions for folate production. Folate production was quantified by microbiological assays by using folate-dependent strain Lactobacillus rhamnosus KCTC 3237. Folate derivatives were identified by LC-MS/MS. Of the 65 strains of bifidobacteria and lactobacilli tested, L. plantarum Fol 708 demonstrated the greatest ability to produce folate. Its optimal pH for folate production was 5.5 in a pH-controlled, lab-scale fermenter. Coculturing L. plantarum Fol 708 with L. brevis GABA 100 in a milk medium enhanced the level of folate produced in comparison to culturing L. plantarum Fol 708 alone.