• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.74-74
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• 2018

Ti-6Al-4V alloys have been widely used as orthopedic materials because of their excellent corrosion resistance and mechanical properties. However, it does not bind directly to the bone, so it requires a surface modification. This problem can be solved by nanotube and micropore formation. Plasma electrolytic oxidation (PEO) treatment for micropore, which combines high-voltage spark and electrochemical oxidation, is a new way of forming a ceramic coating on light metals such as titanium and its alloys. This method has excellent reproducibility and can easily control the shape and size of the Ti alloy. In this study, formation of bioactive surface by PEO-treatment after $2^{nd}$ ATO technique of Ti-6Al-4V alloy was invesgated by various instrument. Nanotube oxide surface structure was formed on the surface by anodic oxidation treatment in 0.8 wt.% NaF and 1M $H_3PO_4$ electrolytes. After nanotube formation, nanotube layer was removed by ultrasonic cleaning. PEO-treatment was carried out at 280V for 3 minutes in the electrolytic solution containing the bioactive substance (Mg, Zn, Mn, Sr, and Si). The surface of Ti-6Al-4V alloy was observed by field emission scanning electron microscopy (FE-SEM, S-4800 Hitachi, Japan). An energy dispersive X-ray spectrometer (EDS, Inca program, Oxford, UK) was used to analyze the spectra of physiologically active Si, Mn, Mg, Zn, and Sr ions. The PEO film formed on the Ti-6Al-4V alloy surface was characterized using an X-ray diffractometer (TF-XRD, X'pert Philips, Netherlands). It is confirmed that bioactive ions play an essential role in the normal bone growth and metabolism of the human skeletal tissues.

• International Journal of Human Ecology
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• v.16 no.2
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• pp.1-9
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• 2015

This study investigated the effects of persimmon-dyed clothing materials upon thermophysiological responses and subjective comfort sensations during exercise and rest in a warm environment. Six healthy, untrained women participated in two separate testing sessions, with cotton materials dyed with astringent persimmon extract (DC) and undyed cotton materials (UDC). The physical characteristics associated with heat and moisture transfer were improved in DC; also, stiffness, anti-drapery stiffness and crispness in the primary hand values were higher in DC. The experimental protocol consisted of a 10-min rest, 15-min exercise on a treadmill (at ${7km{\cdot}h^{-1}}$) and 25-min recovery at $28{\pm}0.2^{\circ}C$ and $50{\pm}3%\;RH$. The results were as follows: When wearing DC rather than UDC, mean body temperature, heart rate, heat storage and body mass loss were significantly lower during the whole experimental period. Clothing microclimate temperature showed different profiles between the two clothing materials, being lower with DC than UDC during the first half of exercise and the second half of recovery. Clothing microclimate humidity was significantly lower with DC than UDC during the whole experimental period. When wearing UDC, subjects felt significantly warmer and less comfortable during exercise, and sensed greater humidity during exercise and recovery. These results suggest that eco-friendly clothing materials dyed with astringent persimmon extract can reduce exercise-induced heat load and improve subjective sensations when exercising and resting in a warm environment, due to greater heat dissipation from the body to the outside environment compared with undyed clothing materials.

• Restorative Dentistry and Endodontics
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• v.47 no.1
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• pp.4.1-4.13
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• 2022

Objectives: This study evaluated the effects of different smear layer preparations on the dentin permeability and microtensile bond strength (µTBS) of 2 self-etching adhesives (Clearfil SE Bond [CSE] and Clearfil Tri-S Bond Universal [CTS]) under dynamic pulpal pressure. Materials and Methods: Human third molars were cut into crown segments. The dentin surfaces were prepared using 4 armamentaria: 600-grit SiC paper, coarse diamond burs, superfine diamond burs, and carbide burs. The pulp chamber of each crown segment was connected to a dynamic intra-pulpal pressure simulation apparatus, and the permeability test was done under a pressure of 15 cmH₂O. The relative permeability (%P) was evaluated on the smear layer-covered and bonded dentin surfaces. The teeth were bonded to either of the adhesives under pulpal pressure simulation, and cut into sticks after 24 hours water storage for the µTBS test. The resin-dentin interface and nanoleakage observations were performed using a scanning electron microscope. Statistical comparisons were done using analysis of variance and post hoc tests. Results: Only the method of surface preparation had a significant effect on permeability (p < 0.05). The smear layers created by the carbide and superfine diamond burs yielded the lowest permeability. CSE demonstrated a higher µTBS, with these values in the superfine diamond and carbide bur groups being the highest. Microscopic evaluation of the resin-dentin interface revealed nanoleakage in the coarse diamond bur and SiC paper groups for both adhesives. Conclusions: Superfine diamond and carbide burs can be recommended for dentin preparation with the use of 2-step CSE.

• Journal of Society of Preventive Korean Medicine
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• v.5 no.1
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• pp.76-89
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• 2001

OMH which is known for its properties of recruiting vitality, is composed of Polygonum multiflorum Thunb. and Sesamum indicum DC.. This formula is known to possess the properties of recruiting vitality, blackening white hair and expanding life span. 16-week-old SD-Rats were treated with OMH for 16 days. After 24 hours, the rats were treated with MTX(Mthotrexate is oral administrated for 4 days(1mg/kg/day), in order to lower immunity. Then, These rats were classified in to groups, the N-16 group(not specially tested), the Control group(MTX), the OMH-L group(2.5% OMH+MTX)&the OMH-H group(10% OMH+MTX) and 6 rats were assigned to each group. After 18 hours from MTX treatment the organ index of the rats from each group Thymus and Spleen were measured. The percentage of CD+4, CD8+ T cell were measured and compared by flow cytometer. 1) Rats from the OHM-L&OMH-H group showed higher organ indexes of the Thymus and Spleen compared to the rats from the Control Group. This proves that OMH possesses the properties to mitigate degenerations of immunity($F_{thymus}=20.162,\;F_{spleen}=5.882$, ANDVA, p<0.05). 2) The rats from the two OMH groups showed higher rates of CD4+ T cell counts compared to the control group(F=26.906, ANOVA, p<0.05). CD8+ T cell showed lower rates compared to the Control group, but showed no differences within the two OMH groups(F=1.254, ANOYA, p>0.05). CD4+/CD8+ showed higher rates in the two OMH groups compared to the control group which can be thought as a proof that OMH prevents depression of immune response(F=10.554, ANOVA, p<0.05). In this test 16 week-old rats were used, which can be considered as the middle and prime age of the human being. These rats were treated with OMH which ended up showing properties of mitigating degeneration of immune responses and maintaining T-cell rates within the blood. It was possible to study that OMH possesses the properties to increase immune responses.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.44-44
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• 2003

As a basic measurement tool in the areas of animal models of human disease, gene expression and therapy, and drug discovery and development, small animal PET imaging is being used increasingly. An ideal small animal PET should have high sensitivity and high and uniform resolution across the field of view to achieve high image quality. However, the combination of long narrow pixellated crystal array and small ring diameter of small animal PET leads to the degradation of spatial resolution for the source located at off center. This degradation of resolution can be improved by determining the depth of interaction (DOI) in the crystal and by taking into account the information in sorting the coincident events. Among a number of 001 identification schemes, dual layer phsowich detector has been widely investigated by many research groups due to its practicability and effectiveness on extracting DOI information. However, the effects of each crystal length composing dual layer phoswich detector on DOI measurements and image qualities were not fully characterized. In order to minimize the DOI effect, the length of each layer of phoswich detector should be optimized. The aim of this study was to perform simulations using a simulation tool, GATE to design the optimum lengths of crystals composing a dual layer phoswich detector. The simulated small PET system employed LSO front layer LuYAP back layer phoswich detector modules and the module consisted of 8${\times}$8 arrays of dual layer crystals with 2 mm ${\times}$ 2 mm sensitive area coupled to a Hamamatsu R7600 00 M64 PSPMT. Sensitivities and variation of radial resolutions were simulated by varying the length of LSO front layer from 0 to 10 mm while the total length (LSO + LuYAP) was fixed to 20 mm for 10 cm diameter ring scanner. The radial resolution uniformity was markedly improved by using DOI information. There existed the optimal lengths of crystal layers to minimize the variation of radial resolutions. In 10 cm ring scanner configuration, the radial resolution was kept below 3.4 mm over 8 cm FOV while the sensitivity was higher than 7.4% for LSO 5 mm : LuYAP 15 mm phoswich detector. In this study, the optimal length of dual layer phoswich detector was derived to achieve high and uniform radial resolution.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.278-286
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• 2008

Many studies regarding Casein phosphopeptides-amorphous calcium phosphate(CPP-ACP) have demonstrated the remineralization ability on the demineralized enamel surface. A question is still remained that how deep can the calcium (Ca) and phosphorus (P) ions supplied by the CPP-ACP paste penetrate into the enamel subsurface. The aims of this study were to measure the penetrating depth of Ca and P ions in the demineralized human enamel in vitro, and were to determine the amount and depth of Ca and P ions according to the duration. The amount and depth of Ca and P ions were measured by microscopic observation with Field Emission Scanning Electron Microscopy (FE-SEM; LEO SUPRA 55, Carl Zeiss, Germany) and Energy Dispersive X-ray Spectrometer (EDS; GENESIS 2000, EDAX, USA: Linescan of Calcium and Phosphorus). Freshly extracted four human 1st premolars were obtained from the Dept. of Pediatric Dent., Kyung Hee Univ. Buccal surfaces of the 1st premolars were covered with nail varnish to form a window on the middle third of buccal surface. All of the teeth with enamel windows were immersed in a solution of 0.1 M lactic acid, Carbopol C907 (carboxypolymethylene BF Goodrich, Cleveland, OH, USA) at pH 4.8, and then incubated for 7 days. Each tooth crown was sawn in half through the midline of buccal window along the long axis of premolar. The four blocks of premolars were immersed in a 10-times diluted solution of CPP-ACP paste (Tooth Mousse, GC Corp., Tokyo, Japan) for 1, 2, 3 and 5 weeks while the rests were immersed in a placebo solution (distilled water) for the same duration. Each specimen was embedded in epoxy resin, and was sectioned perpendicular to the window, using a water-cooled diamond blade saw. The spectrum density indices of Ca and P were measured in the sound, de- and remineralized enamels by FE-SEM and EDS. The Student's t test was performed to compare the Spectrum Density Indices (SDI) of sound, re-and demineralized enamels, and to compare the differences among the durations. Followings are the conclusion : 1. The penetration depth of the remineralizing ions (Ca & P) of CPP-ACP paste is related to the depth of demineralized enamel (approximately $1050{\sim}1350{\mu}m$). It is revealed that the penetration depth of both ions reaches full thickness of decalcification and even slightly into the sound enamel. 2. The Ca & P levels of remineralized enamels in 1, 2 weeks were significantly higher than those of the sound enamels (p<0.05). 3. No statistically significant difference of Ca & P levels was found in relation with the increasing duration of remineralization (p>0.05).

• Analytical Science and Technology
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• v.25 no.6
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• pp.460-466
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• 2012

An environmentally friendly, so-called green, high performance liquid chromatography method was developed and validated for the determination of trans, trans-muconic acid (t,t-MA) in human urine as a biomarker of benzene exposure. After urinary t,t-MA was extracted and enriched using solid-phase extraction, a MF-Ph1 SG80 ($150mm{\times}2.0mm$ I.D., 5 ${\mu}m$) column with a mobile phase of 10 mM $KH_2PO_4$ containing 0.1% $H_3PO_4$ was used for isocratic separation of t,t-MA with UV detection at 259 nm. The calibration curve was constructed in the range of 0.1-5.0 mg/L with good linearity ($r^2$=0.9992). The intra-day and inter-day precision (as RSD) were 0.9-8.5% and 3.1-4.5%, respectively. The average recovery ranged from 97.5% to 101.7%. The green sample preparation and separation with no organic solvents were successfully achieved. The validated method would be suitable for the routine biological monitoring of benzene exposure in the occupational settings.

• Journal of the Korean Society of Food Culture
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• v.19 no.5
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• pp.566-572
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• 2004

This study was carried out to examine the changes of pH, chlorophyll, chlorophyll patterns and ascorbic acid contents, and sensory evaluation in Oi-Kimhi by the different periods of storage. The contents of chlorophyll a and b were 52.2% and 14.44% at storage 0 days, 20.67% and 16.99% at storage 11 days,0% at storage 14 days, and decreased with storage times increased. But, phephorbide a and b were increased with storage times increased until storage 11 days, and were 28.44% and 1.25% at storage 0 days,42.63% and 15.79% at storage 11 days,0% at storage 12, 14 days. The contents of ascorbic acid were increased until storage 4 days, but afterwards were decreased with storage times increased, and were 2.57mg% at storage 0 days, 5.49mg% and 2.95mg% at storage 11 days, 0% at storage 14 days. Sensory evaluations of appearance, flavor, taste, texture, overall acceptability showed the highest at storage 8 days, and disliked after storage 10 days.

• International Journal of Human Ecology
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• v.6 no.2
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• pp.1-9
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• 2005

The purpose of this study was to investigate the effects of two kinds of underwear material on subjects exercising and resting in an ambient temperature of $20^{\circ}C$, a relative humidity of 60% and an air velocity of 0.13m $see^{-1}$. Two kinds of underwear ensemble were tested, differing in their hygroscopic properties: 100% wool (W) with higher moisture regain and 100% cotton (C) with lower moisture regain. Five young females served as subjects. The experiments comprised two repeated periods of 15 min exercise on a treadmill with a speed of 6km $h^{-1}$ followed by 10 min rest. The main results were as follows: 1) Mean skin temperature was significantly higher in W than in C throughout the whole experimental period (p<0.05). 2) The temperature and humidity of the microclimate between the skin and underwear provided by the first layer of clothing was higher in W than in C (p<0.1 and p<0.05, for temperature and humidity, respectively). 3) Heart rate was significantly higher in W than in C (p<0.05). 4) Subjects felt warmer during the second exercise session when wearing wool rather than cotton (p<0.05), and they also reported more increased wetness during the second exercise and rest periods in W than in C (p<0.05). These results suggest that underwear made of wool with higher moisture regain might not act as effectively as cotton to transfer exercise-induced heat from the body to the surrounding air when light exercise is taken in a thermally-neutral environment.

• The Journal of Pediatrics of Korean Medicine
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• v.22 no.3
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• pp.105-137
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• 2008

Objectives : The purpose of this study is to investigate the effect of Gupoongjeseuptang (GPJST) on atopic dermatitis by in vivo experiment using NC/Nga atopic dermatitis mouse, which has histological and clinical similarities to the atopic dermatitis of human. Methods : To investigate the effect of GPJST on atopic dermatifis, we evaluated atopic dermatitis-like skin lesions by clinical skin index and analyzed immunological parameters in peripheral blood mononuclear cells (PBMCs), splenocytes, draining lymph node (DLN) and performed skin histology in ears and dorsal skin of atopic dermatitis-like skin NC/Nga mouse in vivo. Results : In vivo, clinical skin severity score were significantly lower in GPJST group than control group. IgE, IL-6, $TNF-{\alpha}$, IgG1, IgM, IgG2a and IgG2b levels in serum decreased remarkably in GPJST group than control group. Also, total absolute number of $CD3^+CD69^+$, and $CCR3^+$ cells recovered as normal in PBMCs and $CD3^+$, $CD3^+CD69^+$ decreased significantly compared with control group in isolated DLN from NC/Nga mouse and total absolute number of $CD11b^+Gr-1^+$, $CCR3^+CD3^+$ in dorsal skin of NC/Nga mouse decreased by GPJST. We analyzed ear and neck-back skin after biopsy and dyeing by hematoxyline/eosin (H&E) and toluidine staining (mast cells marker) and obtained results that GPJST are very effective to histological symptoms (dermal and epidermal thickening, hyperkeratosis and inflammatory cell (CD4, $CCR3^+$) infiltration). Conclusions : This study demonstrates immunological activity of GPJST on atopic dermatitis-like model mice.