• Korean Chemical Engineering Research
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• v.62 no.3
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• pp.233-237
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• 2024

This study is about the fabrication of a flexible electrode based on PAN-based carbon fibers tow using organic/inorganic nanocomposite and its application of non-enzymatic sensor. The organic/inorganic nanocomposite was composed of the conductive polymer polyaniline (PANI) and the metal oxide CuO. And glucose was used as the target of the electrochemical sensor. Commercialized CFTs were pretreated through heat treatment for desizing and electrochemical oxidation for activation. This nanocomposite was sequentially synthesized on the pretreated CFT surface using electrochemical polymerization and electrochemical deposition. Finally, the CFT/PANI/CuO NPs electrode was obtained. The electrochemical properties and sensing performance of the CFT/PANI/CuO NPs electrode were analyzed using chronoamperometry (CA), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The sensitivity of the CFT/PANI/CuO NPs electrode was about 8.352 mA/mM (in a linear range of 0.445~6.674 mM) and 3.369 mA/mM (in a linear range of 6.674~50 mM), respectively. So, the CFT/PANI/CuO NPs electrode exhibited the enhanced sensing performances due to unique properties such as small peak potential separation, low electron transfer resistance, and large specific surface area.

• Journal of Life Science
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• v.20 no.4
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• pp.535-542
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• 2010

This study was carried out to examine anthropometric parameters and related habits in female college students. Mean age, height, and body weight of the subjects in total (n=212) were 20.7 yrs, 161.8 cm, and 53.5 kg, respectively. Anthropometric parameters were measured by bioelectrical impedance analysis. Mean degree of obesity, body mass index (BMI), and waist-hip ratio (WHR) were 98.4%, $20.6\;kg/m^2$, and 0.80 respectively. Surprisingly, 63.7% of the subjects showed unbalanced weak upper bodies compared to their lower bodies. Therefore, they were divided into two groups: unbalanced weak upper body group (UU, n=135) and balanced upper body groups (BU, n=77). Bodyweight, degree of obesity, BMI, and WHR in the UU group were significantly lower than those in the BU group. Amounts of body protein, body fat, and body mineral in the UU group were also significantly lower than those of the BU group. Mid-arm muscle circumference of the UU group ($18.5{\pm}0.8\;cm$) was significantly lower than those of BU group ($20.4{\pm}1.2\;cm$), although mid-arm circumference of the UU group was not significantly different compared to those of the BU group. On a questionnaire on exercise habits, 1.5% of the UU group and 7.8% of the BU group answered that they exercised regularly, and 55.5% of the UU group and 31.2% of the BU group reported that they never exercised (p<0.01). Even in the subjects who exercised, the duration of the exercise was not sufficient because 38.4% of the UU group and 35.8% of the BU group answered that they exercised for less than 30 min. In conclusion, interventions in exercise habits may be needed for female college students who have unbalanced weak upper bodies.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.7
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• pp.966-974
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• 2010

The aim of this study was to examine characteristics between nutrient intakes, body composition and physical fitness in gifted athletic boys. The subjects were conducted in 50 boys aged 9~12 years living in Busan, Ulsan and Gyeongsangnam-do, Korea. Dietary intake information was collected from participants using 3-day food recorded and body composition was measured by bioelectrical impedance analysis, and their anthropometric parameters were measured. Swimming group's daily energy intakes were significantly higher compared to those of other groups. Athletics and swimming groups were significantly taller than gymnastics. Swimming group was significantly higher than gymnastics group in weight, fat mass, body fat percent and lean body mass. Athletics and swimming groups were significantly longer than gymnastics group in sit and ball throwing. Swimming group was significantly better than other groups in sit up, and athletics group was significantly faster than gymnastics group in 50 m run. In correlation result for nutrient intake and body composition: 1) Body weight shows positive correlation with protein, phosphorus, sodium, vitamin $B_1$, C and niacin. BMI shows positive correlation with sodium and niacin. Fat mass shows positive correlation with niacin and folate. Body fat% shows positive correlation with vitamin C, E, niacin and folate. LBM shows positive correlation with all elements except lipid, calcium, vitamin A, C, E and folate. In correlation result for nutrient intake and physical fitness: 2) Push up shows positive correlation with iron and vitamin C. Sit and throw ball shows positive correlation with the events except lipid, fiber, vitamin A, E and folate. Sit up shows positive correlation with vitamin $B_1$. Half squat shows positive correlation with iron. Standing long jump shows positive correlation with total energy, lipid, and vitamin A, B and $B_2$. Long run shows negative correlation with protein, carbohydrate, fiber, phosphorus, iron, sodium and zinc. Side step shows positive correlation with niacin. Sit and reach shows negative correlation with total energy, carbohydrate, phosphorus, sodium, zinc and vitamin $B_2$. In correlation result for body composition and physical fitness: 3) Sit and throw ball shows positive correlation with body weight, BMI, fat mass, body fat% and LBM. Standing long jump shows positive correlation with LBM. But long run and 50 m run shows negative correlation with body weight and LBM.

• Geophysics and Geophysical Exploration
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• v.13 no.1
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• pp.1-8
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• 2010

Seismic reflection surveying is one of the most widely used and effective techniques for coal seam structure delineation and risk mitigation for underground longwall mining. However, the ability of the method can be compromised by the presence of volcanic cover. This problem arises within parts of the Bowen and Sydney Basins of Australia and seismic surveying can be unsuccessful. As a consequence, such areas are less attractive for coal mining. Techniques to improve the success of seismic surveying over basalt flows are needed. In this paper, we use elastic wave-equation-based forward modelling techniques to investigate the effects and characteristics of seismic wave propagation under different settings involving changes in basalt properties, its thickness, lateral extent, relative position to the shot position and various forms of inhomogeneity. The modelling results suggests that: 1) basalts with high impedance contrasts and multiple flows generate strong multiples and weak reflectors; 2) thin basalts have less effect than thick basalts; 3) partial basalt cover has less effect than full basalt cover; 4) low frequency seismic waves (especially at large offsets) have better penetration through the basalt than high frequency waves; and 5) the deeper the coal seams are below basalts of limited extent, the less influence the basalts will have on the wave propagation. In addition to providing insights into the issues that arise when seismic surveying under basalts, these observations suggest that careful management of seismic noise and the acquisition of long-offset seismic data with low-frequency geophones have the potential to improve the seismic results.

• Journal of Applied Biological Chemistry
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• v.52 no.1
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• pp.8-14
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• 2009

This study was conducted to assess the effects of diet food containing Jerusalem artichoke's inulin, lotus leaf, and herb on weight and body fat. Participants in this study were selected based on the following criteria: BMI over $25kg/m^2$, body fat percentage higher than 25%, abdominal obesity level of 0.85 measured by body composition measurement unit (ZEUS 9.9 PLUS, Korea) total 24 female and male university students over 20 of age were assigned to two different groups: control group and diet group and the study was carried out for 30 days. When we measured what the tester's body weight and height, we used an automatic measure machin which is called IMI-1000 from Immanuel company and when we measured what the hip and wist circumference, we used a tape measure. When we measured body mss index (BMI), body Int, body mass, lean mass, waist/hip ratio (WHB), obesity index, we used a ZEUS9.9 PLUS-Korea which is based on bioelectrical impedance analysis, The food intake was checked by means of diet record method to be input into CAN program in order to analyze nutrient intake. Our findings indicated that the diet group, as compared to the control group, lost weight of approximately 2.5 kg and showed statistically significant difference. In addition the level of body Int, muscle, abdominal obesity, obesity, waist and bottom measurement all showed significant decrease after study period. However, there was no big difference in body fat percentage because both body fat level and muscle level dropped together, Putting all these together, diet food in this study containing Jerusalem artichoke's inulin, lotus leaf powder, and herbs powder including nettle, eucalyptus was found to be effective in significant reduction of weight and body fat and obesity-related body indicators. Also, it is considered that this diet food has potential to prevent and improve effectively obesity from abnormal fat accumulation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.192-201
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• 2003

In this paper, to reduce the size of patch, three types of 3-dimensional patch antennas which are one-directionally-corrugaged type, rectangular ring-likely corrugated type, and lattice-likely corrugated type rectangular microstrip patch antennas(MPA) are designed and fabricated at the 1.575 GHz. As the result, one-directionally corrugated rectangular MPA is reduced in the resonant length of patch by 21.4% than that of general plane MPA. -10 dB bandwidth(B.W) is 62 MHz(3.9 %) and this is broader than that(39 MHz, 2.5 %) of plane MPA by 23 MHz(1.5 %). The gain is 5.8 dBd and this is reduced by 0.9 dB than that(6.7 dBd) of plane MPA. Half power beamwidth(HPBW) is broadened by 18$^{\circ}$ than that of plane MPA in the E-plane and this is due to the reduced length of patch. For rectangular ring-likely corrugated retangular MPA, the patch size is miniaturized by 21.6 % than that of plane MPA. For lattice-likely corrugated rectangular MPA, in the linear polarization, the size of patch is miniaturized by 43.3 % than that of plane MPA. -10 dB B.W is 70 MHz(4.4 %) and this is broadened than that of plane MPA by 31 MHz(2 %). Gain is 2.2 dBd and this is smaller than that of plane MPA by 4.5 dB. HPBW is increased in both E-plane and H-plane by 22$^{\circ}$ and 13$^{\circ}$, respectively. For circular polarization, the size of patch is reduced by 41 % than that by 41 %. The axial ratio(AR) is 0.8 dB at the 1.575 GHz and the axial ratio bandwidth(ARBW) within 2 dB is 20 MHz(1.27 %) and this is increased by 10 MHz(0.63 %) than that 10 MHz(0.63 %) of plane MPA. From all the results above, it is conformed that the proposed antenna has merit in size reduction of patch and in the input impedance B.W, and is more profitable in many application than the general plane type MPA.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.784-795
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• 2007

In this thesis, the Multi element antenna with wideband and enhanced gain characteristic is proposed to operate at both frequency range from 824 MHz to 896 11Hz for the CDMA and frequency range from 908.5 MHz to 914 MHz for the RFID band. The proposed antenna has tile size of $35{\times}15{\times}5mm^3$ in order to put it in the A model of S company and each element of the proposed antenna is folded to obtain the minimum size. To obtain the antenna with wideband and high gain characteristic, the radiator of the antenna is divided into 4 elements. As a result, bandwidth of the proposed antenna become broader and lower center frequency is appeared due to increased and lengthened current path. Moreover, the enhanced gain characteristic is verified because divided element structure that induct uniform current distribution can get increased antenna efficiency. To attain more uniform current distribution, modified structure of the feeding point that can deliver currents directly is designed. The antenna that alters the feeding structure has higher gain value. Each element is folded to increase the current paths considering the current directions to attain the miniaturization of the antenna. To measure the handset antenna, the handset case must be considered. Even though antenna is designed for predicted characteristic, the resonance frequency is shifted and antenna gain is deteriorated at predicted frequency while antenna is set in the handset case. 1.08 GHz of the resonant frequency is determined after frequency shift from 150 MHz to 200 MHz is confirmed and the maximum gain is measured as 3.1 dBi while antenna is not set in the handset. In case handset case is considered, the experimental results show that the impedance bandwidth for VSWR<2 is from 0.824 GHz to 0.936 GHz(110 MHz). This result appears that the proposed antenna can cover both CDMA and RFID band at once. The measured gain is from -3.4 dBi to -0.5 dBi and it has omni-directional pattern practically.

• Clinical and Experimental Pediatrics
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• v.49 no.5
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• pp.475-481
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• 2006

Purpose : As the prevalence of childhood obesity is increasing, hypertension, hyperlipidemia, insulin resistance and diabetes mellitus have become problems. High homocysteine levels and low vitamin $B_{12}$ supplementation are acknowledged to have a role in coronary artery disease, but there are few studies on homocysteine, insulin and vitamin $B_{12}$ levels in obese children. We aimed to study whether homocysteine, insulin, vitamin $B_{12}$, folic acid levels could have any difference and relation in obese children. Methods : The disease group consisted of 27 children from 8 to 11 years old, whose obesity index was over 130. The control group consisted of 30 healthy children of the same age group. Obesity index and body mass index were calculated by height and body weight of the children, and their systolic and diastolic blood pressures at resting state were checked. Total cholesterol, triglyceride, homocysteine, insulin, vitamin $B_{12}$, folic acid levels were studied after 10 hours of fasting. Intracellular fluid, extracellular fluid, protein, mineral, muscle mass, lean body fat, fat mass and fat percentages were checked by bioelectrical impedance. Results : Homocysteine levels were higher in obese children($8.1{\pm}2.1{\mu}mol/mL$ vs. $4.9{\pm}1.0{\mu}mol/mL$). Insulin levels were also higher in obese children($26.8{\pm}11.2{\mu}IU/mL$ vs. $12.5{\pm}5.24{\mu}IUl/mL$). Vitamin $B_{12}$ was lower in obese children($798.6{\pm}174.3pg/mL$ vs. $967.8{\pm}405.0pg/mL$). But there was not a difference in the folic acid levels between the two groups. In obese children, systolic blood pressure (r=0.535), triglyceride(r=0.517), total cholesterol(r=0.408), folic acid(r=0.408), vitamin $B_{12}$(r=0.338) and abdomoanl fat %(r=0.306) had a positive correlation. Conclusion : We found definite differences of insulin, homocysteine, and vitamin $B_{12}$ plasma levels in obese children, but we need more study to use those parameters as risk factors of metabolic syndrome in pediatric obese patients.

• Clinical and Experimental Pediatrics
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• v.48 no.6
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• pp.588-593
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• 2005

Purpose : Obesity is associated with disturbances of ventilatory functions in adults. But few studies have evaluated the pulmonary complications of obesity in the pediatric population. The purpose of this study is to clarify the effects of obesity on pulmonary function and body composition in obese children. Methods : Forty seven obese children whose ages ranged from nine to twelve years were evaluated for their body composition(intracellular fluid, extracellular fluid, protein mass, mineral mass, soft lean mass, fat mass, percent body fat, fat distribution) by bioelectrical impedance analysis. Hemoglobin, serum glucose, aspartate aminotransferase(AST), alanine aminotransferase(ALT), total cholesterol and triglycerides were measured. Pulmonary function test was performed by spirometer. Results : Intracellular fluid, protein mass, fat mass, percent body fat and fat distribution were significantly higher in severely obese children with an obesity index of more than 150 percent compared with those with an index of less than 150 percent. Peak expiratory flow rate(PEFR) was significantly lower in severely obese children with obesity index of more than 150 percent compared with those with less than 150 percent($241.7{\pm}14.6L/sec$ vs $276.8{\pm}64.3L/sec$). PEFR, forced expiratory flow 25 percent($FEF_{25}$), mid expiratory flow rate(MEFR), forced expiratory flow 50 percent($FEF_{50}$), forced expiratory volume in 1st second($FEV_1$) and forced vital capacity(FVC) were decreased in 37.0 percent, 14.8 percent, 14.8 percent, 11.1 percent, 3.7 percent and 3.7 percent of obese children, respectively. Conclusion : PEFR was significantly decreased in obese children. Pulmonary function test must be performed in severely obese children and more extended study is needed in other age groups.

• Progress in Medical Physics
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• v.19 no.1
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• pp.73-79
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• 2008

Retinal prosthesis is regarded as the most feasible method for the blind caused by retinal diseases such as retinitis pigmentosa (RP) or age related macular degeneration (AMD). Recently Korean consortium launched for developing retinal prosthesis. One of the prerequisites for the success of retinal prosthesis is the optimization of the electrical stimuli applied through the prosthesis. Since electrical characteristics of degenerate retina are expected to differ from those of normal retina, we performed voltage stimulation experiment both in normal and degenerate retina to provide a guideline for the optimization of electrical stimulation for the upcoming prosthesis. After isolation of retina, retinal patch was attached with the ganglion cell side facing the surface of microelectrode arrays (MEA). $8{\times}8$ grid layout MEA (electrode diameter: $30{\mu}m$, electrode spacing: $200{\mu}m$, and impedance: $50k{\Omega}$ at 1 kHz) was used to record in-vitro retinal ganglion cell activity. Mono-polar electrical stimulation was applied through one of the 60 MEA channel, and the remaining channels were used for recording. The electrical stimulus was a constant voltage, charge-balanced biphasic, anodic-first square wave pulse without interphase delay, and 50 trains of pulse was applied with a period of 2 sec. Different electrical stimuli were applied. First, pulse amplitude was varied (voltage: $0.5{\sim}3.0V$). Second, pulse duration was varied $(100{\sim}1,200{\mu}s)$. Evoked responses were analyzed by PSTH from averaged data with 50 trials. Charge density was calculated with Ohm's and Coulomb's law. In normal retina, by varying the pulse amplitude from 0.5 to 3V with fixed duration of $500{\mu}s$, the threshold level for reliable ganglion cell response was found at 1.5V. The calculated threshold of charge density was $2.123mC/cm^2$. By varying the pulse duration from 100 to $1,200{\mu}s$ with fixed amplitude of 2V, the threshold level was found at $300{\mu}s$. The calculated threhold of charge density was $1.698mC/cm^2$. Even after the block of ON-pathway with L-(1)-2-amino-4-phosphonobutyric acid (APB), electrical stimulus evoked ganglion cell activities. In this APB-induced degenerate retina, by varying the pulse duration from 100 to $1200{\mu}s$ with fixed voltage of 2 V, the threshold level was found at $300{\mu}s$, which is the same with normal retina. More experiment with APB-induced degenerate retina is needed to make a clear comparison of threshold of charge density between normal and degenerate retina.