• Tribology and Lubricants
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• v.19 no.2
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• pp.72-77
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• 2003

Chitosan derivatives, Fluorinated chitosan, and N,N,N-Trimethyl chitosan iodide were synthesized as the disperse phases for the electrorheological fluid. The synthesis of these materials were confirmed by Fourier transform infrared spectroscopy (FT-lR). Chitosan derivative suspensions showed ER effect under the electric field. Especially, N,N,N-Trimethyl chitosan iodide suspension showed better electrorheological and electric properties than Fluorinated chitosan. It is due to difference in electron strength of polar groups composed derivatives. N,N,N-Trimethyl chitosan iodide suspension exhibited a linear dependence on an electric field power of 2.07.

• Korean Journal of Materials Research
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• v.26 no.1
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• pp.1-7
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• 2016

The graphene oxides (GOs) were tested as a fluorescent quencher in the field of DNA-diagnostics. The various suspensions of GO nanoplates were prepared by changing the synthesis conditions. The suspensions were stable for at least 6 weeks by differing degrees of functionalization of various oxygen-containing groups of atoms. Depending on the properties of GO nanoplates, their fluorescent quenching abilities, which were determined by the amount of the tagged immobilized oligonucleotide, were also changed. GO suspension synthesized at $75^{\circ}C$ of reaction mixture showed the fluorescent quenching of 16.39 nmol/mg, which would be a potential substitution of molecular fluorescent quencher in test-systems for DNA-diagnostics.

• Journal of Acupuncture Research
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• v.26 no.4
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• pp.99-106
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• 2009

Objectives : The antidepressant effect of the subchronic administration of the methanolic extract of wild ginseng(WG) was investigated compared with that of cultivated ginseng(CG, panax ginseng) extract. Methods : To assess the antidepressant effect of the ginseng extracts, tail suspension test(TST) was executed in mice after daily administration of WG or CG extract for five consecutive days. Results : The WG extract at daily dose of 600mg/kg significantly reduced the total duration of immobility in the TST, whereas there was no significant reduction at daily dose of 300mg/kg WG and 600mg/kg CG. There were no individual differences between experimental groups in open field test (OFT) to evaluate psychostimulant effects of WG or CG extract. In the high performance liquid chromatography(HPLC) analysis of the extracts, it was found that WG included four times more ginsenoside Rg1 and Re, three times more Rf, and six times more Rb1 and Rc than CG. Conclusions : It is suggested that WG extract has stronger antidepressant effect than CG extract, which means it includes more antidepressant compounds than CG.

• Journal of Oriental Neuropsychiatry
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• v.21 no.2
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• pp.61-73
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• 2010

Objectives : The purpose of this study was to assess anti-depressive effects of Bee Venom(BV) on an Animal Model of Depression induced immobility stress. Methods : There was 2 pre-experiments MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and Western blot test and 3 main experiments ; forced swimming test, tail suspension test and Y-maze task. Male rats were used for main experiment. The subject was divided into 4 groups(1. control group injected only saline, without immobility stress 2. Negative group injected saline after 2 hours immobility stress 3. Positive group injected Amitriptyline after 2 hours immobility stress 4. BV group injected Bee Venom after 2 hours immobility stress). Each group consisted of 6 rats. Forced swimming test, tail suspension test, Y-maze task were used to evaluate anti-depressive effect of Bee Venom. Results : In MTT assay, as the density of BV increased, the existence rate of primary neuronal cell increased. In Western blot test, the density of CREB and AKT was increasing as time went by. In forced swimming test, BV group showed immobility decreased more than Normal group and Positive group. In tail suspension test, Normal group and Positive group showed immobility decreased more than BV group. In Y-maze task, BV group showed immobility decreased more than Normal group, but Positive group showed immobility decreased more than BV group. Conclusions : These results suggest that Bee Venom may have anti-depressive effect on depression.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.628-633
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• 2013

Carbon black was surface-modified to prepare styrene-based suspension polymerized toner with excellent carbon black dispersibility inside toner particles. Carbon black was oxidized first to introduce hydroxyl groups on the surfaces, then esterification between the hydroxyl groups and carboxyl groups of organic acids (oleic acid, palmitic acid, acrylic acid) was followed to obtain organically surface-modified carbon black. The surface-modification of carbon black was confirmed by FTIR. Apparent carbon black dispersibility in the monomer mixture of the binder resin was tested and the particle size of dispersed carbon black was measured by particle size analyzer. Optical micrographs showed that carbon black dispersibility inside toner particles was improved considerably when the carbon black surfacemodified with oleic acid was used. The polymerized toner prepared with the carbon black surface-modified with oleic acid showed ideal particle size and size distribution as a toner.

• Physical Therapy Korea
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• v.9 no.1
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• pp.17-42
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• 2002

The purpose of this study was to investigate the treatment effect of three interventions on the disuse atrophy of rat hindlimb after two weeks suspension. Forty-eight 11~12 weeks old female Sprague-Dawley white rats were divided into four intervention groups: 1) suspension only (S; n=10), 2) intensive weight bearing treadmill (IWBT; n=10), 3) electrical stimulation (ES; n=9), 4) 2)+3) (ES/IWBT; n=9). Another 10 rats received no intervention or hindlimb suspension and served as controls (C). After the interventions, 1) the cross-sectional area (CSA), 2) the ratio of white muscle fiber composition (WMFC), 3) isometric tetanic tension (ITT), and 4) muscle weights (MWs) were measured from the four calf muscle specimens. The results were as follows: 1. In all intervention groups, the CSAs of medial and lateral gastrocnemius (MG LG), soleus (SOL), and flexor digitorum superficialis (FDS) decreased when compared to the control (C) group (p<.05). The CSA increased in FDS and LG for the IWBT group, in SOL for the ES/IWBT group compared to the S only group (p<.05). 2. The ratios of WMFC in MG, LG, SOL, and FDS increased compared to the C group for all interventions (p<.05). The ratios of WMFC decreased in SOL and LG for the IWBT group, in SOL for the ES/IWBT group compared to the S only group, and decreased in SOL for the ES/IWBT group compared to the IWBT group (p<.05). 3. The ITT in the MG, LG, SOL, and FDS decreased compared to the C group for all interventions (p<.05). The ITT increased in MG LG/FDS, SOL, and the whole calf muscles (WCMs) in the IWBT, ES and ES/IWBT groups compared to the S only group (p<.05). 4. The MWs in MG LG/FDS, SOL, WCMs decreased compared to the C group for all interventions (p<.05). The MWs increased in MG LG/FDS and WCMs for the IWBT group, in SOL for the ES group, and in SOL for the ES/IWBT group compared to the S only group (p<.05). 5. In atrophied muscles, the IWBT group showed the best recovery and the ES/IWBT and ES groups followed in decreasing order. The most susceptible muscle to disuse atrophy was the SOL. But conversely, it showed the best recovery in the ES/IWBT group. After two weeks of hindlimb suspension, the calf muscles of rats atrophied and their isometric tension decreased. These changes were best reversed by hindlimb-focused treadmill activity. The next best results were achieved by electrical stimulation combined with the treadmill followed by only electrical stimulation. These findings indicate that full weight bearing treadmill activity alone or in combination with electrical stimulation are effective treatments for non-weight bearing induced muscle atrophy. Further study of the effect of different intensities of electrical stimulation and variations in the duration period of full weight bearing treadmill activity on disuse atrophy is recommended.

• The Korean Journal of Physiology
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• v.9 no.1
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• pp.1-11
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• 1975

The present experiments were carried out to investigate the active center of sodium and potassium ion activated adenosine triphosphatase. An ATPase, activated by sodium ion Plus potassium ion in the presence of magnesium ion, and inhibited by ouabain, has been obtained from rabbit red cell ghosts. The ATPase activity was measured by inorganie phosphate released from ATP. From this values of the measured inorganic phosphate, the activity of ATPase was calculated. The following results were observed. 1. The activity of $(Na^++K^+)-ATPase$ is inhibited by ouabain. This effect may not be due to an effect on sulfhydryl groups, amino groups, carboxyl groups, imidazole groups and hydroxyl groups. 2. The $(Na^++K^+)$-activated enzyme system is inhibited by p-chloromercuribenzoate and by d nitroflurobenzene, and this effect may be due to an effect on sulfhydryl groups. These results indicate that the sulfhydryl groups is attached to sodium-potassium dependent adenosine triphosphate, an aspect of the pump. 3. The $(Na^++K^+)-activated$ enzyme system is inhibited by maleic anhydride and this inhibition is reversed by lysine. This Seems to indicate that the active center of this enzyme is the amino groups. 4. The $(Na^++K^+)$-activated enzyme system is inhibited by iodoacetamide and this inhibition is reversed by the simultaneous present of cysteine and aspartic acid in the suspension medium. This result indicates that this enzyme contains sulfhydryl groups and carboxyl groups. 5. The $(Na^++K^+)-ATPase$ activity is accelerated by adrenaline and this effect is abolished by aspartic acid. This effect of aspartic acid indicate that carboxyl group might be involved in the hydrolysis of ATP by the enzyme system. On the hydrolysis of ATP by the enzyme system. On the basis of these experiments it f·as suggested that the active center of $(Na^++K^+)-activated$ ATPase contains sulfhydryl groups, amino groups and carboxyl groups.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3269-3273
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• 2013

Graphene oxide (GO) has been of particular interest because it provides unique properties due to its high surface area, chemical functionality and ease of mass production. GO is produced by chemical exfoliation of graphite and is decorated with oxygen-containing groups such as phenol hydroxyl, epoxide groups and ionizable carboxylic acid groups. Due to the presence of those functional groups, GO can be utilized as a novel platform for hybrid nanocomposites in chemical synthetic approaches. In this work, GO-$SnO_2$ nanocomposites have been prepared through the spontaneous formation of molecular hybrids. When $SnO_2$ precursor solution and GO suspension were simply mixed, $Sn^{2+}$ was spontaneously formed into $SnO_2$ nanoparticles upon the deoxygenation of GO. Through further chemical reduction by adding hydrazine, reduced GO-$SnO_2$ hybrid was finally created. Our investigation for the electrocapacitive properties of hybrid electrode showed the enhanced performance (389 F/g), compared with rGO-only electrode (241 F/g). Our approach offers a scalable, robust synthetic route to prepare graphene-based nanocomposites for supercapacitor electrode via spontaneous hybridization.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.711-721
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• 2014

PPWS, a large number of which a main cable of a suspension bridge consists of, must be precisely erected at a target location under construction considering the differences among design conditions. The absolute sag is measured for several PPWSs, which are reference strands and the relative sag is surveyed from them to other PPWSs, which are divided into several groups. And the adjustment of PPWS length is performed to erect it at target configuration. When PPWS is being under erection in a real bridge site, the procedures are as follows; evaluate sag sensitivities according to sag variation factors, calculate an adjustment length of PPWS corresponding to them and adjust a sag of PPWS by controlling the calculated amount of PPWS length. In this study, the differential-related equations of sag sensitivity were proposed for support movement of PPWS. Before site demonstration study of a series of them, we established a catenary model system and accomplished verification tests of them. From test results, the validation of them was done.

• Journal of Biosystems Engineering
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• v.28 no.4
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• pp.351-360
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• 2003

This study was carried out to settle the plugging problem which occurs frequently when agricultural wettable powder is used in pest control work using the crushing and the dispersing effects caused by irradiation of ultrasonic wave. Sonication was applied to the wettable powder suspension in a beaker for 30 seconds using a 28 kHz, 200 W PZT BLT, and the image of suspension before and after sonication was observed using a microscope and a SEM. The image of tow commercial wettable powder suspensions in water observed using an optics microscope showed that the agglomerated particles were irregularly distributed over the whole observed region when stirred mechanically, while showing more uniform distribution composed of comparatively single particles in the whole observed region after sonication. Concerning the above, the projected areas of particles in the four suspensions after sonication were decreased distinctively in the observed range of the microscope and the atomization of crystals was much developed. Over the measured range of 5.6∼4,157 ${\mu}$m particle size, the overall projected area of particles was decreased to 58.3∼89.6% on the average after sonication. When the SEM images of sonicated wettable powder suspensions dissolved in water and CH$_3$OH were compared to the suspensions before sonication, such phenomena as the atomization of particles, the expansion of voids between particles, the reduction and the decrease of agglomerated particle groups, and the progress of crack developments on the surface of flake-shaped particles were observed. It seemed possible that the plugging problem that occurs frequently in pest control machine when using wettable powder would be settled by the use of sonication.