• YAKHAK HOEJI
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• v.46 no.2
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• pp.124-128
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• 2002

The nitrone-based free radical trapping reagent, $\alpha$-phenyl-n-tert-butyl nitrone (PBN) has been proposed as therapeutic agent for stroke. We used this for model drug of development of new drug for neuroprotection. The purpose of this study was to evaluate the blood-brain barrier (BBB) permeability of PBN in Sprague-Dawly (SD) rats. The BBB transport of PBN was investigated in SD rats using internal carotid artery perfusion (ICAP) method at a rate of 4 mι/min for 15 second. We also obtained pharmacokinetic parameters of PBN using single intravenous injection technique. When we estimated BBB permeability of PBN with ICAP method, the brain volume of distribution of PBN was 60.0 $\pm$ 12.0 $\mu\textrm{g}$/ι. The brain uptake of PBN after IV injection at 120 min was 0.15 $\pm$ 0.01%ID/g. The PBN was transported to the brain through the BBB well in rats, because PBN is small molecule (MW 177) and lipid-soluble (log P 1.23) compound.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.17 no.1
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• pp.13-17
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• 2011

There is a need in food industry to store minimally processed garlic for long time to have it be used just at the time of demand for final product processing. Optimal modified atmosphere packaging is expected to slow down the quality change extending its storage life. In order to find optimal packaging conditions, plastic films of different gas permeability properties (low density polyethylene (LDPE) $30{\mu}m$, polyolefin $50{\mu}m$ (PD 900), polyolefin $20{\mu}m$ (PD 941)) were used for packaging 400 g of minimally processed garlic. Perforated LDPE packages were prepared as control. The packaged products were stored at $1{\pm}1^{\circ}C$ for 52 days. Package treatments were compared in weight loss, decay, surface color, hardness and soluble solid content. While control package had normal atmosphere of air, LDPE, PD 900 and PD 941 packages attained internal concentration of $O_2$ 4.6% / $CO_2$ 12%, $O_2$ 0.9% / $CO_2$ 21% and $O_2$ 0.5% / $CO_2$ 13% after 45 days, respectively. Control packaging had rapid weight loss with high mold decay and great surface color change in 45 days. In PD 900 film packages of lowest gas permeability, the fresh-cut garlic could be stored without mold decay for 52 days. Except control packaging, there were no significant differences in surface color, hardness and soluble solid content among package treatments.

• Journal of the Korean Magnetics Society
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• v.5 no.6
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• pp.937-946
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• 1995

In this research, the processing control of NiCuZn Ferrite has been developed. The relationship between initial permeability and bulk density of NiCuZn Ferrite with processing factors was studied. NiCuZn Ferrite, which calcinated at $700^{\circ}C$ for 3 hours, was ball milled for about 60 hours to make a size of $0.5\mu\textrm{m}$ followed by granulation using spray dryer. The physical properties and the magnetic properties of NiCuZn Ferrite were investigated with the processing factor, such as (i) granule size and forming pressure, and (ii) sintering temperature. The green density of NiCuZn Ferrite was largely depended on the forming pressure rather than its granule size. The green density of NiCuZn Ferrite was increased from $2.484\;g/cm^{3}$ to $3.002\;g/cm^{3}$ with increase in forming pressure. The bulk density of NiCuZn Ferrite was increased from $3.470\;g/cm^{3}$ to $4.754\;g/cm^{3}$ linearly with increase in sintering temperature. The relationship between initial permeability and bulk density of NiCuZn Ferrite was expressed with the empirical equation,$\mu_{i}=a+b_{\rho}+c_{\rho}^2$ at forming pressure and sintering temperature.

• Journal of the Korean Magnetics Society
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• v.25 no.4
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• pp.129-137
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• 2015

The Cu(radius ra = $95{\mu}m$)/$Ni_{80}Fe_{20}$(outer radius $r_b$ = $120{\mu}m$) core/shell composite wire is fabricated by electrodeposition. The two diagonal components of impedance tensor for the Cu/$Ni_{80}Fe_{20}$ core/shell composite wire in cylindrical coordinates, $Z_{zz}$ and $Z_{{\theta}{\theta}}$, are measured as a function of frequency in 10 kHz~10 MHz and external static magnetic field in 0 Oe~200 Oe. The equations expressing the diagonal $Z_{zz}$ and $Z_{{\theta}{\theta}}$ in terms of diagonal components of complex permeability tensor, ${\mu}^*_{zz}$ and ${\mu}^*_{{\theta}{\theta}}$, are derived from Maxwell's equations. The real and imaginary parts of ${\mu}^*_{zz}$(f) and ${\mu}^*_{{\theta}{\theta}}$(f) spectra are extracted from the measured $Z_{zz}$(f) and $Z_{{\theta}{\theta}}$(f) spectra, respectively. It is presened that the extraction of ${\mu}^*_{zz}$(f) and ${\mu}^*_{{\theta}{\theta}}$(f) spectra from the diagonal impedance spectra can be a versatile tool to investigate dymanic magnetization process in the core/shell composite wire.

• Archives of Pharmacal Research
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• v.24 no.6
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• pp.584-589
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• 2001

Isopropryl 2-(1-3-dithiethane-2-ylidene)-2 [N-(4-methyl-thiazole-2-yl) carbamoyl] acetate (YH439) is currently under phase ll clinical trials by the Yuhan Research Center for use as a hepatoprotective agent. Unfortunately, the oral bioavailbility of YH439, which is sparingly soluble in water (i.e., $0.3{\;}\mu\textrm{g}/ml{\;}or{\;}0.91{$\mu}M$ at room temperature), reportedly, is negligibleregardless of the dose administered to rats in the 10-300 mg/kg range. The bioavailability of the compound increased up to 24%, when administered in the form of a micellar solution ($700{\;}\mu\textrm{g}/ml$or 2.1 mM for YH439) at a dose of 10 mg/kg, suggesting that its limited solubility is associated with its negligible bioavailability. In order to obtain additional informmation concerning the bioavailability of YH439, the mechanism(s) involved in gastrointestinal (Gl) absorption were investigated in the present study. For this purpose, the transport of YH430 across a Caco-2 cell monolayer was measured in a $Transwell^{\circledR}$. A permeability of $4.07{\times}10^{-5}{\;}cm/s$ was obtained for the absorptive (i.e., apical to basolateral direction) transport of $0.42{\mu}M$ YH439, implicating that the in vivo Cl absorption is nearly complete. The absorptive transport exhibited a slight concentration-dependency with an intrinsic clearance ($CL_{i}$) of $0.38{\mu}L/{\textrm{cm}^2}/sec$, which accounted for 28.1% of the total intrinsic clearance (i.e., $CL_i$ plus the intrinsic clearance for the linear component) of the transport. Thus, saturation of the absorption process appears to be a minor factor in limiting the bioavailability of the compound. The apparent permeability of YH439 from the basolateral to the apical direction (i.e., efflux, $6.67{\times}10^{-5}{\;}cm/s$) was comparable to that for absorptive transport, but, interestingly, a more distinct concentration-dependency was observed for this transport. However, the efflux does not appear to influence the bioavailability of the compound, as evidenced by the sufficiently high permeability in the absorption direction. Rather, a reportedly extensive first-pass hepatic metabolism appears to be a principal factor in limiting the bioavailability. In this respect, reducing the first-pass metabolism by some means would lead to a higher bioavailability of the compound. Thus, elevation of the absorption rate of YH439 becomes a necessity. From a practical point of view, increasing the concentration of YH439 in the Cl fluid appears to be a feasible way to increase the absorption rate, because the compound is primarily absorbed via a linear mechanism. In summary, the solubilization of YH439, as previously demonstrated for a micellar solution of the compound, appears to be a practical way to increase the oral bioavailability of YH439.

• Resources Recycling
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• v.13 no.6
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• pp.37-42
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• 2004

The power loss analysis was carried out for Ni-Cu-Zn ferrite sample with different content of NiO and ZnO. The power loss, Pcv decreases monotonically with increasing temperature and attains to a certain value at around 100~120 degrees Celsius. The frequency dependence of Pcv can be explained by Pcv~f$^n$, and n is independent of the frequency, f up to 1 MHz. The Pcv decreases with an increase in ZnO/NiO. The Pcv was separated to hysteresis loss(Ph) and residual loss(Pcv-Ph). The temperature characteristics and compositional dependence of Pcv can be attributed to the Ph, while Pcv-Ph is not affected by both temperature and ZnO/NiO. By analyzing temperature and composition dependence of Ph and initial permeability, ${\mu}_i$ like following equations could be formularized. ${\mu}_i{\mu}_0=I_s^2/(K_I+b{\sigma}_0{\lambda}_s)$ Wh=13.5(I$_s^2/{\mu}_i{\mu}_0)$ Where ${\mu}_0$ is permeability of vacuum, I$_s$ is saturation magnetization, K$_I$ is anisotropy constant, $s_0$ is internal heterogeneous stress, ${\lambda}_s$ is magnetostriction constant, b is unknown constant, and Wh is hysteresis loss per one cycle of excitation (Ph=Wh${\times}$f). Steinmetz constant of Ni-Cu-Zn ferrite, m=1.64~2.2 is smaller than that of Mn-Zn ferrites, which suggests the difference of loss mechanisms between these materials.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2004.12a
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• pp.3-11
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• 2004

The power loss analysis was carried out for Ni-Cu-Zn ferrite samples with different content of NiO and ZnO. The power loss, Pcv decreases monotonically wi increasing temperature and attains to a certain value at around $100\~120$ degrees Celsius. The frequency dependence of Pcv can be explained by $Pcv\~f^n$', and n is independent of the frequency, f up to 1MHz. The Pcv decreases with an increase in ZnO/NiO. The Pcv was separated to hysteresis loss, Ph and residual loss, (Pcv-Ph). The temperature characteristics and compositional dependence of Pcv can be attributed to the Ph, while (Pcv-Ph) is not affected by both temperature and ZnO/NiO. By analyzing temperature and composition dependence of Ph and initial permeability, ${\mu}^i$ following equations could be formularized. $${\mu}_i{\mu}o=I_x\;^2/(K_1+bs_ol_s)\;\;\;\;(1)$$ $Wh=13.5(I_s\;^2/{\mu}_i{\mu}_o)\;\;\;\;(2)$$ Were ${\mu}_o$ is permeability of vacuum, $I_s$ saturation magnetization, $K_1$ anisotropy constant, $S_o$ internal heterogeneous stress, $I_s$, magnetostriction constant, b unknown constant. Wh hysteresis loss per one cycle of excitation (Ph: Wh*f). Steinmetz constant of Ni-Cu-Zn ferrites, $m=1.64\~2.2$ is smaller than the one of Mn-Zn ferrites, which suggests the difference of loss mechanism between these materials.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.10a
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• pp.157.2-157
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• 2000

• Restorative Dentistry and Endodontics
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• v.27 no.4
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• pp.382-388
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• 2002

Compomer is composed of matrix and filler : matrix is made of the combination of resins and polycarboxylic molecules that are light-cured, and a filler is a glass component which is capable of ion-release. The resin content of compomers produces polymerization shrinkage which can adversely affect marginal adaptation. Pretreatment is a fundamental step which is treated with conditioner or primer in the use of these materials. Microleakage of restorative materials has been investigated mostly by dye penetration method. Dye penetration method was not quantitative and not measured repeatedly. Fluid filtration method, introduced and developed by Pashley's group, has been extensively used for 20 years for research purpose to understand the physiology of dentin, as well as the effects of various restorative treatments on dentin permeability. It permits quantitative, nondestructive measurment of microleakage in a longitudinal manner. The purpose of this study was to evaluate the change of dentin permeability according to the process of compomer restoration. In this study. Cl V cavities were prepared on buccal surface of thirty extracted human molars. The prepared cavities were etched by 37% phosphoric acid. The experimental teeth were randomly divided into three groups. Each group was treated with following materials Group 1 : Prime & Bond NT/Dyract AP, Group2： Single Bond/F2000 compomer, Group 3 : Syntac Single Component/Compoglass. The bonding agent and compomer were applied for each group following manufacturers information. Dentin permeability of each group was measured at each process by fluid filtration method; Step 1 : preparation(smear layer). Step 2 : etching(smear layer removal), Step 3 : applying the bonding agent, Step 4 : filling the compomer. Dentin permeability was expressed by hydraulic conductance ($\mu\textrm{l}$ min$^{-1}$cm$H_2O$$^{-1}$). The data were analysed statistically using One-way ANOVA and Sheffe's method. The results were as follows : 1. Dentin permeability differences between each process were significant except between step 1 and step 2(p<0.01). 2. Dentin permeability after removal of smear layer was highly increased(p<0.01). 3. In most case, decrease of dentin permeability was obtained by applying bonding agent(p<0.01). 4. Dentin permeability differences among the experimental groups were not significant(p>0.05). 5. None of compomers used in this study showed perfect seal at the interface.

• Journal of the Korean Magnetics Society
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• v.12 no.2
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• pp.51-56
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• 2002

Permalloy thin films fabricated by rf magnetron sputtering showed the excellent magnetic properties, i.e., an effective permeability of over 2000 at 1$\mu\textrm{m}$ thick up to 10 MHz, a saturation magnetization of 10∼12 kG, a coercive force of 0.2∼1 Oe, resistivity (p) is 20 ${\mu}$$\Omega$cm. In order to control the magnetic anisotropy direction of the films in a wafer scale, two parallel Nd-Fe-B permenant mangnets were used to provide the magnetic field during the sputtering process. As a result, the anisotropy direction was successfully controlled when the two magnets were seperated with a distance of 70 mm. 3D simmulation of the magnteic fields around the wafer during sputtering were in accord with the above result.