• Journal of the Korean Applied Science and Technology
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• v.36 no.2
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• pp.572-580
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• 2019

Recently, it has been reported that benzyl alcohol (BzOH) as an additive in cosmetics, food, and medicine lead to toxicity and allergy problem. Then, to circumvent this hurdle, we carried out the synthesis of benzyl alcohol galactoside (BzO-gal). Previously, it was confirmed that BzO-gal was synthesized by transgalactosylation reaction using Escherichia coli (E. coli) ${\beta}$-galactosidase (${\beta}-gal$). Meanwhile, in this study, two peaks of BzO-gal as sodium adduct ion (m/z=293.1004) and protonated ion (m/z=271.1180) were detected in the reaction mixture by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS). In addition, the amount of ${\beta}-gal$ and BzOH concentration, temperature, pH, and lactose concentration, respectively, were optimized (${\beta}-gal$, 0.75 U/mL; BzOH, 185 mM; temperature, $40^{\circ}C$, pH, 7.5; lactose, 350 g/l). Under these optimal conditions, 185 mM BzOH was converted into about 131 mM BzO-gal, in which the conversion yield was about 72%. In the future, BzO-gal will be applicable as a substitute for BzOH as a less toxic preservative for the cosmetic, pharmaceutical, and food industries, and we are planning to investigate the characteristics of BzO-gal as a preservative.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1439-1444
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• 2006

A $Cu^{2+}$ ion-selective membrane microelectrode has been fabricated from poly vinyl chloride (PVC) matrix membrane containing a new symmetrical hexadentate Schiff,s base 2-{1-(E)-2-((Z)-2-{(E)-2-[(Z)-1-(2-hydroxyphenyl)ethylidene]hydrazono}-1-methylpropylidene)hydrazono]ethyl}phenol (HDNOS) as a neutral carrier, Potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic excluder and o-nitrophenyloctyl ether (NPOE) as a plasticizing solvent mediator. The microelectrode displays linear potential response in the concentration range of $1.0\;{\times}\;10^{-5}-1.0\;{\times}\;10^{-11}$ M of $Cu^{2+}$. The microelectrode exhibits a nice Nernstian slope of 25.9 ${\pm}$ 0.3 mV $decade^{-1}$ in the pH range of 3.1-8.1. The sensor has a relatively short response time in whole concentration ranges ($\sim$5 s). The detection limit of proposed sensor is $5.0\;{\times}\;10^{-12}$ M (320 pg/L), and it can be used over a period of eight weeks. The practical utility of the sensor has been demonstrated by using it as an indicator electrode in the potentiometric titration of $Cu^{2+}$ with EDTA. The proposed membrane electrode was used for the direct determining of $Cu^{2+}$ content in black and red pepper, and in waste water samples.

• Bulletin of the Korean Space Science Society
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• 1996.11a
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• pp.9-9
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• 1996

No Abstract, See Full Text

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.12
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• pp.936-941
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• 2010

In this study, we have investigated the effects of Mn dopant on the bulk trap levels and grain boundary characteristics of $Bi_2O_3$-based ZnO (ZB) varistor using admittance spectroscopy and dielectric functions (such as $Z^*,\;Y^*,\;M^*,\;\varepsilon^*$, and $tan\delta$). Admittance spectra and dielectric functions show two bulk traps of $Zn_i^{..}$ (0.20 eV) and $V^{\bullet}_o$ (0.29~0.33 eV) in ZnO-$Bi_2O_3-Mn_3O_4$ (ZBM). The barrier of grain boundaries in ZBM could be electrochemically single type. However, its thermal stability was slightly disturbed by ambient oxygen because the apparent activation energy of grain boundaries was changed from 0.79 eV at lower temperature to 1.08 eV at higher temperature. The grain boundary capacitance $C_{gb}$ was decreased slightly with temperature as 1.3~1.8 nF but resistance $R_{gb}$ decreased exponentially. The relaxation time distribution can result from the heterogeneity of the barriers constituting the varistor. It is revealed that Mn dopant in ZB reduced the heterogeneity of the barrier in grain boundaries and stabilized the barrier against the ambient temperature.

• ETRI Journal
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• v.34 no.3
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• pp.361-368
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• 2012

A complete high-frequency small-signal circuit model of a 40 Gb/s butterfly electroabsorption modulator integrated laser module is presented for the first time to analyze and optimize its electro-optic (E/O) response and reflection characteristics. An agreement between measured and simulated results demonstrates the accuracy and validity of the procedures. By optimizing the bonding wire length and the impedance of the coplanar waveguide transmission lines, the E/O response increases approximately 5% to 15% from 20 GHz to 33 GHz, while the signal injection efficiency increases from approximately 15% to 25% over 18 GHz to 35 GHz.

• Journal of the Mineralogical Society of Korea
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• v.15 no.1
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• pp.78-84
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• 2002

New pyrochlore-type phases($A_2$$B_2$$O_{7}$) were synthesized in the systems: CaO-C$eO_2$-T$iO_2$, CaO-$UO_2$(T$hO_2$)-Z$rO_2$, CaO-$UO_2$(T$hO_2$)-$Gd_2$$O_3$-T$iO_2$-Z$rO_2$, 및 CaO-T$hO_2$-S$nO_2$. The starting materials were pressed with the pressure of 200~400 MPa and sintered at 1500~ 155$0^{\circ}C$ for 4~8 hours in air and at 1300~ 135$0^{\circ}C$ for 5 ~50 hours under oxygen atmosphere. The products were characterized using XRD, SEM/EDS and TEM. In the bulk compositions of CaCe$Ti_2$$O_{7}$, CaTh$Zr_2$$O_{7}$,($Ca_{0.5}$ Gd$Th_{0.5}$)(ZrTi)$O_{7}$) ($Ca_{0.5}$Gd$Th_{0.5}$)(ZrTi)$O_{7}$, ($Ca_{0.5}$G$dU_{0.5}$)(ZrTi)$O_{7}$ and CaTh$Sn_2$$O_{7}$ , pyrochlore was the major phase, together with other oxide phase $of_2$$O_{7}$ fluorite structure. In the samples with target compositions CaU$Zr_2$$O_2$및 $Ca_{0.5}$ G$dU_{0.5}$)$Zr_2$T$iO_{7}$ pyrochlore was not identified, but a fluorite-structured phase was detected. The formation factor as the stable phase depended on crystal chemical characteristics of the actinide and lanthanide elements of the system concerned.

• Journal of Korean Medicine Rehabilitation
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• v.15 no.2
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• pp.141-154
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• 2005

Objectives : This study was planned to evaluate clinical status of the alopecia patients who had visited oriental medicine clinic. Methods : 80 patients with alopecia, who had visited oriental medicine clinic from January 2004 to August 2004, were examined. Results & Conclusions : 1. The kinds and incidences of Alopecia : androgenetic alopecia 57.5%(46/80), alopecia areatea 20.0%(16/80), telogen effluvium 16.3%(13/80), seborrheic alopecia 6.3%(5/80). 2. In distribution of sex, the rate of male to female was 1:1 and most patients belonged to 20-30 year old group. 3. The most common onset of age was adolescence(63.8%) and the most common duration of hair loss was 1 to 3 years. 4. Among the 30 male androgenetic alopecia patients, Hamilton's type 4 was most common and among the 16 female androgenetic alopecia patients, Ludwig's type II and III were most common. 5. Family history of baldness in Androgenetic alopecia and alopecia areata were 56.5% and 25.0%, respectively. 6. Self-conscious causes of hair loss : stress(48.8%), irregular eating habits(21.3%), and lack of sleep(20.0%). 7. Associated diseases with alopecia patients : chronic neck pain(58.8%), temporomandibular disorders(55.0%) and seborrheic dermatitis(20.0%). 8. Associated symptoms with alopecia Patients : stress(78.8%), sleep disorders(68.8%), irregular eating habits(55.0%), Hot flush(43.8%), Stool disorders(43.8%), cold hands and feet(37.5%) and menstruation disorders(31.3%). 9. The most common scalp type was oily scalp(70.0%) and the symptoms of scalp were iching, dandruff, pain, inflammation. 10. $Bi{\grave{a}}n$ $zh{\grave{e}}ng$(辨證) of alopecia patients : $xu{\grave{e}}-r{\grave{e}}-f{\bar{e}}ng-z{\grave{a}}u$(血熱風燥) (25.0%), $g{\bar{a}}n-sh{\grave{e}}n-b{\grave{u}}-z{\acute{u}}$(肝腎不足) (23.8%), $shi-r{\grave{e}}-sh{\grave{a}}ng-zh{\bar{e}}ng$(濕熱上蒸) (16.3%), $xu{\grave{e}}-r{\grave{e}}-sh{\bar{e}}ng-f{\bar{e}}ng$(血熱生風) (13.8%), $xu{\grave{e}}-x{\bar{u}}-f{\bar{e}}ng-z{\grave{a}}u$(血熱風燥) (13.8%), $y{\bar{u}}-xu{\grave{e}}-z{\check{u}}-lu{\grave{o}}$(瘀血阻絡) (7.5%).

• Electrical & Electronic Materials
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• v.16 no.9
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• pp.65.1-65
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• 2003

The interface of zirconium oxide thin films on silicon is analyzed in detail for their potential applications in the microelectronics. The formation of an interfacial layer of ZrSi$\sub$x/O$\sub$y. with graded Zr concentration is observed by the x-ray photoelectron spectroscopy and secondary ion mass spectrometry analysis. The as-deposited ZrO$_2$/ZrSi$\sub$x/O$\sub$y//Si sample is thermally stable up to 880$^{\circ}C$, but is less stable compared to the ZrO$_2$/SiO$_2$/Si samples. Post-deposition annealing in oxygen or ammonia improved the thermal stability of as-deposited ZrO$_2$/ZrSi$\sub$x/O$\sub$y/Si to 925$^{\circ}C$, likely due to the oxidation/nitridation of the interface. The as-deposited film had an equivalent oxide thickness of∼13 nm with a dielectric constant of ∼21 and a leakage current of 3.2${\times}$10e-3 A/$\textrm{cm}^2$ at 1.5V. Upon oxygen or ammonia annealing, the formation of SiO$\sub$x/ and SiH$\sub$x/N$\sub$y/O$\sub$z/ at the interface reduced the overall dielectric constants.

• Archives of Pharmacal Research
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• v.26 no.1
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• pp.34-39
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• 2003

The traditional Asian medicinal herb, roots of Astragalus (A.) membranaceus (Leguminosae), is used for many purposes, some of which are purported to stimulate the release of growth hormone in vivo. Extracts of A. membranaceus were tested to determine whether they stimulate the release of growth hormone in rat pituitary cell culture. A. membranaceus was extracted sequentially with 80% ethanol (fraction A), n-hexane (fraction B); the test compound from the herbal extraction was isolated using silica gel column chromatography and was identified with spectral data. Test compound was also extracted by traditional boiling water methods. Induction of growth hormone in pituitary cell culture was conducted with isolated compounds and extracted fractions of A. Radix (dried roots of A. membranaceus). The fraction A was not active in the rat pituitary cell culture, but the fraction B derived from the ethanol fraction stimulated the release of growth hormone in culture. Six compounds from fraction B (1-6) were isolated and identified previously. The compounds 1,2-benzendicarboxylic acid diisononylester (1), $\beta$-sitosterol (2), and 3-Ο-$\beta$-D-galactopyranosyl-$\beta$-sitosterol (5) did not induce growth hormone release in the culture. Formononetin (3), 9Z, 12Z-octadecadienoic acid (4), stigmast-4-en-6$\beta$-o1-3-one (6) and 98-E, a mixture of 1'-9, 12-octadecadienoic acid (Z,Z)-2',3'-dihydroxy-propylester (7) and 1'-hexadecanoic acid-2',3'-dihydroxy-propylester (8) stimulated the release of growth hormone in the rat pituitary cell culture significantly compared to the control. In conclusions, four compounds isolated from extracts of A. Radix induced growth hormone release in the rat pituitary cell culture. The 98-E isolate was the most active inducer of growth hormone release.

• Journal of Microbiology and Biotechnology
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• v.31 no.4
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• pp.550-558
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• 2021

Lactobacillus kefiranofaciens contains two types of β-galactosidase, LacLM and LacZ, belonging to different glycoside hydrolase families. The difference in function between them has been unclear so far for practical application. In this study, LacLM and LacZ from L. kefiranofaciens ATCC51647 were cloned into constitutive lactobacillal expression vector pMG36e, respectively. Furtherly, pMG36n-lacs was constructed from pMG36e-lacs by replacing erythromycin with nisin as selective marker for food-grade expressing systems in Lactobacillus plantarum WCFS1, designated recombinant LacLM and LacZ respectively. The results from hydrolysis of o-nitrophenyl-β-galactopyranoside (ONPG) showed that the β-galactosidases activity of the recombinant LacLM and LacZ was 1460% and 670% higher than that of the original L. kefiranofaciens. Moreover, the lactose hydrolytic activity of recombinant LacLM was higher than that of LacZ in milk. Nevertheless, compare to LacZ, in 25% lactose solution the galacto-oligosaccharides (GOS) production of recombinant LacLM was lower. Therefore, two β-galactopyranosides could play different roles in carbohydrate metabolism of L. kefiranofaciens. In addition, the maximal growth rate of two recombinant strains were evaluated with different temperature level and nisin concentration in fermentation assay for practical purpose. The results displayed that 37℃ and 20-40 U/ml nisin were the optimal fermentation conditions for the growth of recombinant β-galactosidase strains. Altogether the food-grade Expression system of recombinant β-galactosidase was feasible for applications in the food and dairy industry.