• Journal of the Korean Chemical Society
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• v.45 no.1
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• pp.51-60
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• 2001

One-pot Mannich reaction of substituted hydroxy aromatic compounds with secondary amines in an aprotic solvent has been studied. The results demonstrate that the relative reactivity and regioselectivity of the Mannich reaction depend on the steric hindrance of amines as well as the nucleophilicity of hydroxy aromatic rings.

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.1939-1944
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• 2011

The nucleophilic substitution reactions of bis(Y-aryl) chlorophosphates (1) with substituted anilines and deuterated anilines are investigated kinetically in acetonitrile at 35.0 $^{\circ}C$. The kinetic results of 1 are compared with those of Y-aryl phenyl chlorophosphates (2). The substrate 1 has one more identical substituent Y compared to substrate 2. The cross-interaction between Y and Y, due to additional substituent Y, is significant enough to result in the change of the sign of cross-interaction constant (CIC) from negative ${\rho}_{XY}$ = -1.31 (2) to positive ${\rho}_{XY}$ = +1.91 (1), indicating the change of reaction mechanism from a concerted $S_N2$ (2) to a stepwise mechanism with a rate-limiting leaving group departure from the intermediate (1). The deuterium kinetic isotope effects (DKIEs) involving deuterated anilines ($XC_6H_4ND_2$) show secondary inverse, $k_H/k_D$ = 0.61-0.87. The DKIEs invariably increase as substituent X changes from electron-donating to electron-withdrawing, while invariably decrease as substituent Y changes from electron-donating to electron-withdrawing. A stepwise mechanism with a rate-limiting bond breaking involving a predominant backside attack is proposed on the basis of positive sign of ${\rho}_{XY}$ and secondary inverse DKIEs.

• The korean journal of orthodontics
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• v.11 no.2
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• pp.57-64
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• 1981

The purpose of this study was to investigate the effect of hydrocortisone in the fusion mechanism of the secondary palatine shelves in the rat. Pregnant rats were injected with 5.0 mg/100 gm body weight of hydrocortisone for 3 days between the 7th day and the 9th day of pregnancy. Between the 14th day md the 18 day of pregnancy, the fetuses were removed and decapitated to be immersed in $10\%$ formalin and Carney's solution. Preparations were stained with alizarin red S, hematoxylin-eosin and alcian blue respectively, and partly were treated for Periodic acid-Schiff reaction. The results were as followings: 1. The incomplete fusion of the palatal epithelium took place though the polarity of epithelial cells. 2. At the edge of shelves the differentiation of mesenchymal cells was observed, but the inter penetration of mesenchyme was not shown. 3. It was considered that the phenomenon of hypocalcification in matrix had relation to the decrease stainability to alizarin red S in shelves. 4. It might be concluded that the connective tissue under epithelium showed the decrease tendency to alcian blue and PAS reaction due to the inhibition of the synthesis of the mucopolysaccharide.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3355-3360
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• 2011

The nucleophilic substitution reactions of 1,2-phenylene phosphorochloridate (1) with substituted anilines ($XC_6H_4NH_2$) and deuterated anilines ($XC_6H_4ND_2$) are investigated kinetically in acetonitrile at $-15.0^{\circ}C$. The studied substrate of 1,2-phenylene phosphorochloridate is cyclic five-membered ring of phosphorus ester, and the anilinolysis rate of 1 is much faster than its acyclic analogue (4: ethyl phenyl chlorophosphate) because of extremely small magnitude of the entropy of activation of 1 compared to 4. The Hammett and Bronsted plots exhibit biphasic concave upwards for substituent X variations in the nucleophiles with a break point at X = 3-Me. The values of deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) change from secondary inverse ($k_H/k_D$ < 1) with the strongly basic anilines to primary normal ($k_H/k_D$ > 1) with the weakly basic anilines. The secondary inverse with the strongly basic anilines and primary normal DKIEs with the weakly basic anilines are rationalized by the transition state (TS) variation from a predominant backside attack to a predominant frontside attack, in which the reaction mechanism is a concerted $S_N2$ pathway. The primary normal DKIEs are substantiated by a hydrogen bonded, four-center-type TS.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2588-2592
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• 2010

The potential energy surfaces (PESs) for the primary and secondary dissociations of the phenylarsane molecular ion (1a) were determined from the quantum chemical calculations using the G3(MP2)//B3LYP method. Several pathways for the loss of $H{\cdot}$ were determined and occurred though rearrangements as well as through direct bond cleavages. The kinetic analysis based on the PES for the primary dissociation showed that the loss of $H_2$ was more favored than the loss of $H{\cdot}$, but the $H{\cdot}$. loss competed with the $H_2$ loss at high energies. The bicyclic isomer, 7-arsa-norcaradiene radical cation, was formed through the 1,2 shift of an $\alpha$-H of 1a and played an important role as an intermediate for the further rearrangements in the loss of $H{\cdot}$ and the losses of $As{\cdot}$ and AsH. The reaction pathways for the formation of the major products in the secondary dissociations of $[M-H]^+$ and $[M-H_2]^{+\cdot}$. were examined. The theoretical prediction explained the previous experimental results for the dissociation at high energies but not the dissociation at low energies.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.32
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• pp.243-253
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• 1994

Work environments have been changed with the advent of new technologies, such as computer technology. The newer technologies, the more changes in our work conditions. However, human cognitive limits can't keep up with the change of work environments. Mental workload has been an important factors in designing modem work environments such as human-computer interaction. Designing man-machine systems requires knowledge and evaluation of the human cognitive processes which control information flow workload. Futhermore, under an urgent situation, human operator may suffer the work stress, work error, and resultant deleterious work performance. To describe the work performance in the urgent work situations, with time stress and dynamic event occurence, a new concept of information density was introduced. For a series of experiments performed for this study, three independent variables(information amount system processing time, information density) were evaluated using such dependent variables as reaction time, number of error, and number of failure. The results of statistical anlysiss indicate that the amount of information effected on all of five dependent measure. Number of failure and number of secondary task score were effected by both amount of information and operational speed of system, but reaction time of secondary task were effected by both amount of information and information density.

• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.381-384
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• 2002

Second-order-rate constants ($k_N$) have been measured spectrophotometrically for the reactions of 4-nitrophenyl 2-thiophenecarboxylate (1a) with a series of secondary alicyclic amines in H2O containing 20 mole % DMSO at 25.0 $^{\circ}C$ . The ester 1a is less reactive than 4-nitrophenyl 2-furoate (1b) but more reactive than 4-nitrophenyl benzoate (1c) except towards piperazinium ion. The Brønsted-type plots for the aminolyses of 1a, 1b and 1c are linear with a $\beta$nuc value of 0.92, 0.84 and 0.85, respectively, indicating that the replacement of the CH=CH group by a sulfur or an oxygen atom in the benzoyl moiety of 1c does not cause any mechanism change. The reaction of piperidine with a series of substituted phenyl 2-thiophenecarboxylates gives a linear Hammett plot with a large $\rho^-$ value ($\rho^-$ = 3.11) when $\sigma^- $ constants are used. The linear Brønsted and Hammett plots with large $\beta$nuc and $\rho^-$ values suggest that the aminolysis of 1a proceeds via rate-determining break-down of the addition intermediate to the products.

• Korean Journal of Clinical Laboratory Science
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• v.36 no.2
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• pp.89-97
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• 2004

Many strains of Staphylococcus aureus were isolated from pus samples from primary, secondary, and tertiary medical institutions and were subjected to an antibiotic sensitivity test. Ciprofloxacin, clindamycin, erythromycin, gentamicin, oxacillin penicillin, tetracycline, trimethoprim/sulfamethoxazole, vancomycin and teicoplanin were used for the antibiotic sensitivity test. The strains showed hightest resistance to penicillin(91%), but all of strains tested were susceptible to vancomycin and teicoplanin. The isolated multi-drug(penicillin-tetracycline-ciprofloxacin-clindamycin-erythromycin- oxacillin-gentamicin) resistant S. aureus were analyzed genotypically using an AP-PCR(Arbitrarily Primed polymerase chain reaction) with an arbitrary 3 primers. Based on the result for genotype analysis, the genotypes identified by S1 primer did not coincide with those of S2 or E2 primers. Genotypes identified by S2 primer did not coincide with those of S1 or E2 primers. Also genotypes identified by the E2 primer did not coincide with those of S1 or S2 primers. Therefore, an analysis of AP-PCR test with multiple primers will provide more sensitive identification. A strain from a secondary medical institution and a strain from a tertiary medical institution which showed the same genotype for S1, S2, and E2 primers are required for further epidemiological study.

• Journal of Hydrogen and New Energy
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• v.27 no.6
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• pp.753-763
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• 2016

High temperature sodium/sulfur battery(Na/S battery) has good electrochemical properties, but, the battery has some problems such as explosion and corrosion at al. because of using the liquid electrodes at high temperature and production of high corrosion. Room temperature sodium/sulfur batteries (NAS batteries) is developed to resolve of the battery problem. To recently, room temperature sodium/sulfur batteries has higher discharge capacity than its of lithium ion battery, however, cycle life of the battery is shorter. Because, the sulfur electrode and electrolyte have some problem such as polysulfide resolution in electrolyte and reaction of anode material and polysulfide. Cycle life of the battery is improved by decrease of polysulfide resolution in electrolyte and block of reaction between anode material and polysulfide. If room temperature sodium/sulfur batteries (NAS batteries) with low cost and high capacity improves cycle life, the batteries will be commercialized batteries for electric storage, electric vehicle, and mobile electric items.

• Journal of Korean Clinical Nursing Research
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• v.24 no.2
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• pp.159-169
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• 2018

Purpose: The purpose of this study was to investigate the reality of workplace violence experienced by emergency nurses and the relationship of violence response to professional quality of life. Methods: The participants in this study were 899 emergency nurses from Korea nationwide. Data were obtained through an online survey done during October, 2017. Data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation coefficient. Results: Of the emergency nurses, 72.1% recognized that workplace violence is serious. Experience with workplace violence correlated positively with violence reaction (r=.32, p<.001), burnout (r-.20, p<.001) and secondary trauma (r=.22, p<.001). Also, reaction to violence was positively correlated with burnout (r=.28, p<.001) and secondary trauma (r=.56, p<.001). Conclusion: Findings indicate that the diverse workplace violence experienced by emergency nurses decreases their professional quality of life. Further study is needed to develop solutions to the problem of workplace violence in emergency settings.