• Bulletin of the Korean Chemical Society
• /
• v.30 no.2
• /
• pp.397-401
• /
• 2009

The complexes of $C_2-\;and\;C_6$-dihydroceramides with transition metal ions have been investigated by using Electrospray ionization-tandem mass spectrometry (ESI-MS/MS). The formation and fragmentation pathways of several doubly charged cluster ions as well as singly charged cluster ions of $C_2-\;and\;C_6$-dihydroceramides with transition metal ions have studied by ESI-MS/MS in the positive mode. Under ESI conditions, dihydroceramides form singly and doubly charged complexes with transition metal ions $(Mn^{2+},\;Fe^{2+},\;Co^{2+},\;Ni^{2+},\;and\;Zn^{2+}\;except\;Cu^{2+})$ with the compositions of $[DHCer+M+2H^2O-H]^+,\;[2DHCer+M+2H2O-H]^+,\;[3DHCer+M+2H2O-H]^+,\;[2DHCer+M]^{2+},\;[3DHCer+M]^{2+},\;[4DHCer+M]^{2+},\;[5DHCer+M]^{2+},\;and\;[6DHCer+M]^{2+}\;(DHCer\;=\;C_2-\;or\;C_6$-dihydroceramide, M = transition metal ion). The different complexation behavior of copper is responsible for relatively lower affinity of dihydroceramides to copper compared to those of other transition metals. It is also found that in the mass spectrum of the dihydroceramide complexes with copper(II), [2DHCer+Cu-H]$^+$ was observed with considerable intensity as well as [2DHCer+Cu+2$H_2O-H]^+$ due to its different geometry from those of other metals.

• Korean Journal of Materials Research
• /
• v.11 no.6
• /
• pp.472-476
• /
• 2001

Type and three-dimensional morphology of carbides precipitated in the X(X= 1.70, 1.92, 2.21, 2.50, 2.86)%C-5%Cr-5%V-5%Mo-5%W-5%Co multi-component white cast iron were investigated using an optical microscope and SEM. The types of carbides precipitated were MC, M$_2$C and M$_{7}$C$_{3}$. Morphology of the MC carbide took three forms, that it petal-like, nodular and coral-like. MC carbide seemed to change its morphology from petal-like through nodular, and finally to coral-like with an increase in carbon content. M7C carbide was classified into lamellar and plate-like type. The lamellar M$_2$C arbide precipitated in the iron with low molybdenum and tungsten contents, and higher contents of both elements in the iron were needed to form the plate-like M$_2$C carbide. The morphology of M$_{7}$C$_{3}$ was rod-like similar to that observed in high chromium white cast iron. However, cobalt does not affect the type and morphology of precipitated carbides.des.

• Journal of the Korean Chemical Society
• /
• v.30 no.3
• /
• pp.273-281
• /
• 1986

This study is focused on the correct measurement of the equations for the determination of the impedance parameters-the differential capacity of the double layer $C_d$, solution resistance $R_Q$, transfer resitance $R_i$, and adsorption pseudcapacity $C_{\phi}$/ The application of only an imaginary part of complex function of ${\omega}$ at the sinusoidal steady state indicates the following equations of total impedance: at low frequency $|Z_{LF}|=1/{\omega}_1\;C_{\phi}\;{\sqrt{1+{{\omega}_1}^2/{\omega}^2}$, at high frequency $|Z_{HF}|={\omega}_2/({\omega}_1{\omega}_3C{\phi})({\omega}^2+{{\omega}_2}^2)\;{\sqrt{{({\omega}^2+{\omega}_2{\omega}_3)}^2+{({\omega}_2{\omega}-{\omega_3{\omega})^2}}$. The values of the total impedance of cell, phase angle, and cell current that are necessary for the calculations of impedance parameters were experimentally measured from 200 to 6000Hz for the following supporting electrolytes, 0.5M $Na_2SO_4$, 1M NaCl, 19.373% sea water, 1M HCl, 1M $KNO_3$ and for $10^{-2}M$ KI and 60mM DBNA (Di-iso-Butylnitrosoamine) in these supporting electrolytes. The derived equations in this study shows that the values of impedance parameters of $C_d,\;C_{\phi},\;R_i\;and\;R_Q\;are\;15{\sim}40\;{\mu}F/cm^2,\;162{\sim}758\;{\mu}F/cm^2\;11.5{\sim}57.6\;ohm{\cdot}cm^2\;and\;0.5{\times}10^{-2}{\sim}4.1{\times}10^{-2}\;ohm{\cdot}cm^2$ respectively.

• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.6
• /
• pp.317-322
• /
• 2016

While PFOS sodium salt ($C_8F_{17}SO_3Na$) was not degraded by microorganisms for 28 days, the 4 alternatives were biodegraded at the rates of 21.6% for $C_{25}F_{17}H_{32}S_3O_{13}Na_3$, 20.5% for $C_{15}F_9H_{21}S_2O_8Na_2$, 15.8% for $C_{23}F_{18}H_{28}S_2O_8Na_2$ and 6.4% for $C_{17}F_9H_{25}S_2O_8Na_2$, respectively. The acute toxicity test using Daphnia magna was conducted for 48 hours, the half effective concentration ($EC_{50}$) of PFOS sodium salt ($C_8F_{17}SO_3Na$) was evaluated in 54.5 mg/L. While the 4 alternatives did not show any effect at 500.0 mg/L. The surface tension of the PFOS salt ($C_8F_{17}SO_3Na$) is 46.2 mN/m at a concentration of 500.0 mg/L. While the surface tension of the 4 alternatives was found to be superior to PFOS sodium salt ($C_8F_{17}SO_3Na$). The surface tension of $C_{23}F_{18}H_{28}S_2O_8Na_2$ (20.9 mN/m) has the lowest, followed by $C_{15}F_9H_{21}S_2O_8Na_2$ (23.4 mN/m), $C_{17}F_9H_{25}S_2O_8Na_2$ (27.3 mN/m), $C_{25}F_{17}H_{32}S_3O_{13}Na_3$ (28.2 mN/m). The four kinds of alternatives ($C_{15}F_9H_{21}S_2O_8Na_2$, $C_{17}F_9H_{25}S_2O_8Na_2$, $C_{23}F_{18}H_{28}S_2O_8Na_2$, $C_{25}F_{17}H_{32}S_3O_{13}Na_3$) were found to be superior to PFOS sodium salt ($C_8F_{17}SO_3Na$) in terms of biodegradation, Daphnia sp. acute toxicity and surface tension, and thus they were considered applicable as PFOS alternatives. Especially biodegradation rate of $C_{15}F_9H_{21}S_2O_8Na_2$, $C_{23}F_{18}H_{28}S_2O_8Na_2$ and $C_{25}F_{17}H_{32}S_3O_{13}Na_3$ was relatively high as 15.8~21.6%, and Daphnia sp. acute toxicity and surface tension were considerably superior (surface tension 39~55%) to PFOS sodium salt. Therefore, these alternatives are considered to be available as an alternative of PFOS.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.19 no.3
• /
• pp.257-264
• /
• 1986

The Chromosomes of five cobitid fishes, Cobitis taenia taenia, C. taenia lutheri, C. taenia striata, C. longicorpus and C. koreensis were studied. The karyotypic studies were based on the observations from the flame-drying preparations. The results obtained such as the number of somatic chromosomes, the type of chromosomes according to the centromeric loci and the number of chromosomal arm(AN) were as follows: C. longicorpus, 2n=50, 12m-8sm-30a, AN=70; C. koreensis, 2n=50, 10m-12sm-28a, AN=72; C. taenia taenia, 2n=48, 14m-4sm-30a, AN=66: C. taenia lutheri, 2n=50, 10m-6sm-34a, AN=66; and C. taenia striata, 2n=50, 10m-6sm-34a, AN=66. Peculiarly, in the case of C. taenia lutheri the chromosome number of somatic diploid was found to be 48-51, however, the number of chromosomal arm was 66, irrespective of the difference in the numbers of each somatic genome. It was confirmed there exists the Robertsonian event, one of the chromosomal polymorphism in C.t. lutheri. It was remarked taxonomically that the karyotype of C. taenia taenia of Korea having 48 diploid chromosomes was not identical with that of Europe and Japan with 50 chromosomes. Based on the karyotype analysis the Korean cobitid fishes can be classified roughly into three species groups according to arm numbers and diploid numbers; 1) C. taenia taenia, C. taenia lutheri, C. taenia striata 2) C. koreensis, C. longicor pus, C. rotundicaudata and 3) C. granoei.

• Korean Journal of Animal Reproduction
• /
• v.16 no.2
• /
• pp.117-123
• /
• 1992

This Study was carried out ot investigate the effects of concentration and equilibration time of cryoprotective aagents on survival rate of slowly and ultrarapidly frozen porcine embryos. The porcine embryos following dehydration by cryoprotective agents and 0.25M sucrose were slowly freezed(from 2$0^{\circ}C$ to -7$^{\circ}C$/-1$^{\circ}C$/min., from -7$^{\circ}C$ to -35$^{\circ}C$/-0.2$^{\circ}C$/min., from -35$^{\circ}C$ to -38$^{\circ}C$/-0.3$^{\circ}C$/min.) by Cell Freezer and directly plunged into liquid nitrogen and thawed in 38$^{\circ}C$ water bath. Survival rate was defined as development rate to the morula and blastocyst stage after in vitro culture or by FDA test. The results are summarized as follows : 1. The survival rates of porcine embryos after slow frozen-thawing in the freezing medium of 0.25M sucrose added 2.0M glycerol, 3.0M DMSO, 2.0M propanediol or 2.0M glycerol＋2.0M propanediol was 80.6, 84.7, 75.0 or 78.8%, respectively. 2. The survival rates of porcine embryos after slow frozen-thawing in the freezing medium of 0.50M sucrose added 2.0M glycerol, 3.0M DMSO, 2.0M propanediol or 2.0M glycerol＋2.0M propanediol was 80.9, 82.4, 73.1 or 77.1%, respectively. 3. The survival rates of porcine embryos after ultrarapid frozen-thawing in the freezing medium of 0.25M sucroese added 2.0M glycerol, 3.0M DMSO, 2.0M propanediol or 2.0M glycerol＋2.0M propanediol was 65.3, 68.6, 63.2 or 59.9%, respectively. 4. The survival rates of porcine embryos after ultrapid frozen-thawing in the freezing medium of 0.50M sucrose added 2.0M glycerol, 3.0M DMSO, 2.0 propanediol or 2.0M glycerol＋2.0M propanediol was 67.5, 62.9, 56.9, or 62.8%, respectively. 5. The higher survival rate of porcine embryos was attained at the short period ofequilibration time(5min.) in the freezing medium added 0.25M sucrose and 3.0 DMSO compared to those of 10 or 20min. equilibration time in the same condition.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.8 no.1
• /
• pp.77-88
• /
• 1981

The purpose of this study was to make a comprehensive study & evaluation of the oral status of mental retarded children. The auther examined intraorally 486 (male; 311, female;175) mental retarded children. The result was as follows; (General mental retarded children means the children who live in their parent's home, & orphan mental retarded children means the children who live in orphanage.) 1. The dft rate was 31.6% in general mental retarded children (G.m.r.c.) & 20.7% in orphan mental retarded children (O. m. r. c.). The dft index was 3.73 in G.m.r.c. & 2.15 in O.m.r.c. 2. The DMFT rate was 24.6% in female G.m.r.c., 16.7% in male G.m.r.c., 12.7% in female O.m.r.c., 8.4% in male O.m.r.c. The DMFT index was 4.94 in female G.m.r.c., 4.01 in male G.m.r.c., 1.40 in male O.m.r.c., 2.75 in female O.m.r.c. 3. The malocclusion prevalence was 57.3%. the class I malocclusion was 14.2% Class II malocclusion 19.3%, Class III malocclusion 23.5%. The children with Down's syndrome had 60.0% of class III malocclusion prevalence. 4. The dental calculus index was 1.97 in male O.m.r.c., 1.81 in female O.m.r.c., 1.30 in male G.m.r.e., 1.13 in female G.m.r.c. 5. The dental plaque index was 3.06 in female G.m.r.c., 3.00 in male Gm.r.e. 2.70 in male O.m.r,c., 2.32 in female O.m.r.c.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.11 no.2
• /
• pp.37-41
• /
• 1982

This study was conducted to investigate the growth of soybean sprouts and the effective hormonal refutation of vitamin C content by the concentration and combination of kinetin and auxins such as IAA, 2.4-D and NAA. The results were as follows; 1. The growth of soybean sprouts were fine under the respective conditions of kinetin $10^{-8}M+IAA\;10^{-6}M$, kinetin $10^{-7}M+IAA\;10^{-5}M$, kinetin $10^{-6}M+IAA\;10^{-6}M$, kinetin $10^{-5}M+IAA\;10^{-7}M$, kinetin $10^{-8}M+2,4-D\;10^{-8}M$ and kinetin $10^{-7}M+NAA\;10^{-5}M$. 2. The root development of soybean sprouts were almost in accord with the growth of soybean sprouts by the concentration of kinetin and auxin. 3. The content of vitamin C were more increased under in kinetin $10^{-8}M+IAA\;10^{-8}M$, kinetin $10^{-6}M+2,4-D\;10^{-5}M$ and kinetin $10^{-8}M+NAA\;10^{-8}M$ and both growth and vitamin C content were more activated under kinetin $10^{-8}M+IAA\;10^{-6}M$ and $10^{-8}M+NAA\;10^{-8}M$. 4. The growth, root development and vitamin C content were increased in the low kinetin and high IAA, NAA concentration. Root development and vitamin C content of soybean hypocotyl were decreased in the low kinetin and high 2,4-D concentration.

• Korean Journal of Mathematics
• /
• v.27 no.2
• /
• pp.437-444
• /
• 2019

For c > -1, let ${\nu}_c$ denote a weighted radial measure on ${\mathbb{C}}$ normalized so that ${\nu}_c(D)=1$. For $c_1,c_2>-1$ and $f{\in}L^1(D^2,\;{\nu}_{c_1}{\times}{\nu}_{c_2})$, we define the weighted Berezin transform $B_{c_1,c_2}f$ on $D^2$ by $$(B_{c_1,c_2})f(z,w)={\displaystyle{\smashmargin2{\int\nolimits_D}{\int\nolimits_D}}}f({\varphi}_z(x),\;{\varphi}_w(y))\;d{\nu}_{c_1}(x)d{\upsilon}_{c_2}(y)$$. This paper is about the space $M^p_{c_1,c_2}$ of function $f{\in}L^p(D^2,\;{\nu}_{c_1}{\times}{\nu}_{c_2})$ ) satisfying $B_{c_1,c_2}f=f$ for $1{\leq}p<{\infty}$. We find the identity operator on $M^p_{c_1,c_2}$ by using invariant Laplacians and we characterize some special type of functions in $M^p_{c_1,c_2}$.

• Korean Journal of Animal Reproduction
• /
• v.15 no.2
• /
• pp.133-139
• /
• 1991

This stduy was carried out in order to investigate the effects of concentration and equilibration time of cryoprotective agents on survival rate of slow and ultrarapidly frozen in vitro fertilized bovine embryos. In vitro fertilized bovine embryos, following dehydration by cryoprotective agents and sucrose, were slowly freezed(from 2$0^{\circ}C$ to -7$^{\circ}C$/-1$^{\circ}C$/min., from -7$^{\circ}C$ -35$^{\circ}C$/-0.2$^{\circ}C$/min. from -35$^{\circ}C$ to -38$^{\circ}C$/-0.3$^{\circ}C$/min.) by cell freezer and directly plunged into liquid nitrogen and thawed in 38$^{\circ}C$ water. Survival rate was defined by development rate to the morula and blastocyst stage after in vitro cultured and FDA test. The results are summarized as follows : 1. The survival rates of in vitro fertilized bovine embryos after slow frozen-thawing in the freezing medium of 0.25M sucrose added 2.5M glycerol, 3.0M DMSO, 2.0M propanediol and 2.5M glycerol＋2.0M propanediol were 84.3%, 85.9%, 77.8%, 74.3%, respectively. 2. The survival rates of in vitro fertilized bovine embryos after slow frozen-thawing in the freezing of 0.50M sucrose added 2.5M glycerol, 3.0M DMSO, 2.0M propanediol and 2.5M glycerol＋2.0M propanediol were 83.8%, 85.1%, 71.4%, 74.6%, respectively. 3. The survival rates of in vitro fertilized bovine embryos after ultrarapid frozen-thawing in the freezing of 0.25M sucrose added 2.5M glycerol, 3.0M DMSO, 2.0M propanediol and 2.5M glycerol＋3.0M propanediol were 69.3%, 70.8%, 63.2%, 67.1%, respectively. 4. The survival rates of in vitro fertilized bovine embryos after ultrarapid frozen-thawing in the freezing of 0.25M sucrose added 2.5M glycerol, 3.0M DMSO, 2.0M propanediol and 2.5M glycerol＋2.0M propanediol were 69.4%, 70.1%, 62.3%, 63.5%, respectively. 5. The survival rates of in vitro fertilized bovine embryos after slow and ultrarapid fromthawing in the freezing medium of sucrose added cryoprotective agents were not significant difference between 5min. and 10min. of equilibration time.