• Korean Journal of Environmental Agriculture
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• v.3 no.1
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• pp.1-9
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• 1984

Two of the degradation products of alachlor in soil. product 1, 2,6-diethyl-N-(methoxymethyl) acetanilide and product 2,2-hydroxy-2',6'-diethyl-(methoxymethyl) acetanilide were synthesized from alachlor reacting with 3N-hydrochloric acid in the presence of zinc powder at room temperature and a saturated sodium bicarbonate solution at $90^{\circ}C$ for 78 hr, respectively. At the concentrations of both $5{\times}10^{-4}M\;and\;1{\times}10^{-3}M$, product 2 exhibited almost the same phytotoxicity to rice seedlings, in particular, as alachlor, whereas product 1 lost its phytotoxic effectiveness. It seems that substitution of chlorine atom by hydroxyl group did not affect the phytotoxicity of alachlor, whereas substitution by hydrogen atom did.

• Journal of the Korean Vacuum Society
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• v.21 no.4
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• pp.212-218
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• 2012

The optical properties of AZO thin films prepared by the RF mangnetron sputtering system was studied to research the dependance of chemical properties of substrate. The substrate was the SiOC film deposited by Inductively coupled plasma chemical vapor deposition with various gas flow rate of $O_2$ and Ar (DMDMOS). In accordance with the increase of Ar gas flow rates, the Si-O bond in the SiOC film increased and then progressed the amorphism. The roughness of AZO grown on SiOC film with high degree of amorphism decreased and then improved the flatness of surfaces. Moreover, the ultra violet emission with high intensity was spontaneously induced in the AZO film growed on SiOC film with high degree of amorphism.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.2 s.21
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• pp.67-76
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• 2005

We synthesized an energetic prepolymer(glycidyl dinitro propyl formal, GDNPF) for plastic-bonded explosive and measured its thermodynamic parameters. Glycidyl dinitro propyl formal(GDNPF) as an energetic monomer was epoxidized from allyl-2,2-dinitro propyl formal which is reacted with dinitro propyl alcohol and excess allyl alcohol, and then energetic polymer of GDNPF was polymerized by cationic ring opening polymerization. Thermodynamic parameters were obtained from the ceiling temperature($T_c$) values of 1 mole monomer at reaction temperature. We varied feed rate of monomer, concentration of initiator and monomer to control molecular weight and polydispersity of prepolymer (GDNPF). The activated monomer polymerization has been executed with precisely controlled feed of GDNPF monomer to reactor in the complex state catalyst generated by $BF_3{\cdot}(C_3H_5)_2$ and 1,4-butanediol in $C_2H_4Cl_2$. Number average molecular weight(Mn), polydispersity(Pd), hydroxy number and glass transition temperature($T_g$) of prepolymer(GDNPF) were $2,500{\sim}3,000,\;1.2{\sim}1,3,\;0.6{\sim}0.8eq/kg\;and\;-20{\sim}-25^{\circ}C$ respectively.

• Korean Journal of Food Science and Technology
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• v.51 no.4
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• pp.393-397
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• 2019

Proteasome inhibitors can promote apoptosis and cell cycle arrest in cancer cells by inhibition of nuclear factorkappaB ($NF-{\kappa}B$) activation. The purpose of this study was to investigate the effects of persimmon leaf extract (PSE) on proteasome activity in HepG2 human liver cancer cells. PSE treatment inhibited the proteasome activity and $NF-{\kappa}B$ activation in a dose-dependent manner in HepG2 human liver cancer cells (p<0.05). PSE treatment increased the population of cells in G2/M and sub-G1 phases. The results suggested that PSE is one of the candidate substances that may be developed into a proteasome inhibitor.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.4
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• pp.367-377
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• 2021

Objectives: Taxi drivers are exposed to various hazards, such as long periods of sedentary work and traffic-related air pollutants. However, studies on the health effects among taxi drivers in South Korea are insufficient. Methods: To assess subclinical hematologic change related to cardiovascular disease among male taxi drivers, we analyzed data from the second Korean National Environmental Health Survey. Fifty-nine taxi drivers and 1,912 controls were included in the analysis. Propensity score matching was performed to adjust for age, body mass index, and urinary cotinine. A total of 295 subjects were matched with 59 taxi drivers. Leukocyte count, platelet count, hematocrit, triglyceride, total cholesterol, HDL cholesterol land total IgE of the taxi drivers were compared with the control groups. Results: Taxi drivers showed significantly elevated blood leukocytes and platelets. Serum total IgE was significantly reduced in taxi drivers. However, blood leukocytes, platelets, and serum total IgE were not significantly correlated with work period among taxi drivers. Conclusions: Regarding the change of the blood leukocyte count, platelet count, and serum total IgE, taxi driving has the possibility to be associated with peripheral inflammation, humoral immunity and cardiovascular risk.

• Polymer(Korea)
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• v.38 no.1
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• pp.9-15
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• 2014

Polyamide4 (PA4)-polyurethane (PU)-PA4 triblock copolymers were synthesized by isocynated (NCO)-terminated PU prepared from 4,4'-diphenyl methane diisocyante (MDI) and polytetramethylene glycol (PTMG) as an initiator and potassium pyrrolidonate (P-py) as a catalyst for anionic ring opening polymerization of 2-pyrrolidone. Subsequently copolymer was controlled to contain different or same molecular weight of PA4 hard block with same or different molecular weight of PU soft block in order to investigate the effects of those differences on various properties of triblock copolymers as a thermoplastic elastomer. As the results shown in typical properties of block copolymeric elastomers, the mechanical strength and melting point ($T_m$) of the copolymers increased with an increase in molecular weight of PA4 block while the elongation at break increased with an increase in that of PU block.

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.610-616
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• 1997

Hepatotoxic cyanobacteria, Microcystis species, were collected from the Nakdong River and we could isolate hepatotoxins, microcystin-LR and microcystin-RR, which are also strong inhibitors of protein phosphatase 1 and 2A. From the microcystins, several microcystin derivatives were synthesized and tested on the mouse toxicity in order to establish the structure-activity relationship. Esterification od carboxyl groups of Glu and MeAsp residue produced nontoxic compounds. However, when we reduced the Mdha residue with sodium borohydride into Ala residue, toxicity was still maintained. Also, the change of guanidyl moiety of Arg residue in microcystin-LR into dimethylpyrimidyl moiety did not change the toxicity of microcystins as well. Thus the carboxyl groups seem to play important roles in binding with protein phosphatase 1 and 2A, whereas Mdha residue and the guanidyl moiety of Arg residue do not.

• Journal of Korean Elementary Science Education
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• v.23 no.1
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• pp.85-91
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• 2004

The illustrations in elementary science textbooks and experimental workbooks based on the 7th national curriculum were analyzed for gender-role stereotyping, and compared with those of the 6th curriculum. The frequencies of men and women who appeared on text illustrations were counted and the types of roles assigned to males and females were investigated. The results were as follows. 1) The 7th national curriculum textbooks contained double the numer of illustrations in the textbooks based on the 6th curriculum. 2) Boys and girls were illustrated in 'learning activities' with equal frequency, but boys were more frequently represented than girls in illustrations of 'other' activities. 3) Both boys and girls were generally depicted in 'active' processes and the ratio of 'passive girl' illustrations decreased as compared with the 6th national curriculum. 4) Male adults were more frequently represented than female adults in both textbooks and experimental workbooks. 5) 40% of female adults were illustrated doing housework, while male adults were rarely illustrated in such a role.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.4
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• pp.587-596
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• 2017

In this study, multi-chambered single autoinjector(2in1) and KMARK-1 containing atropine and 2-PAM(pyridine-2-aldoxime methylchloride) were administered to the beagle's muscle, and blood samples were taken for a certain period of time to compare and evaluate the pharmacokinetic profiles of the two drugs. Male beagles were used and classified into two test groups(G1, G2), and crossover pharmacokinetic studies were performed in two test groups. Blood samples were collected from the jugular vein for analysis after administration. The 90 % confidence interval(CI) for log transformed data indicated that the Cmax for both atropine(log 0.9683 ~ log 1.113) and 2-PAM(log 0.9453 ~ log 1.214) was within the limits of bioequivalence criteria, but the AUC for atropine(log 1.1786 ~ log 1.3238) failed to meet this criteria. This is expected as the amount of atropine dose is 25 % higher for the test as compared to the reference formulation. In summary, in view of the ATNAA(antidote for nerve agent of US) authorization, the Cmax equivalence was more important than AUC equivalence, so in this study, we also focused on verifying the equality of Cmax between the two autoinjectors.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.85-90
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• 2018

The objective of this paper is to observe effects of ignition position and time on ignition transition. A gaseous oxygen and liquid kerosene mixture is used as propellant with a shear-coaxial injector. In order to study the ignition delay time and combustion instability intensity, the pressure transducer was used. Sequences, excepting igniter operation time, were fixed to compare the ignition time only. Initial pressure peak and ignition delay time increased as the ignition time was delayed. Additionally, an unstable flame development zone was detected when the igniter was away from the injector.