• Title/Summary/Keyword: Leaving group

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Effects of Infection Control Education for Families of VRE Patients (VRE 환자의 보호자를 위한 감염관리 교육의 효과)

  • Seo, Jung;Kang, Ji-Yeon
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.19 no.2
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    • pp.212-222
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    • 2012
  • Purpose: The purpose of this study was to examine the effects of infection control education for families of patients infected with vancomycin resistant enterococcus (VRE). Method: Forty family members of VRE patients were chosen from a university hospital and assigned to the experimental or control group. The experimental group was provided infection control education that consisted of one-on-one instruction using an information booklet, hand-washing video, and demonstration of hand washing practice. Dependent variables were self-reported knowledge and performance of VRE infection control measures, and the number of hand washings when entering and leaving patients' rooms. Results: Knowledge and performance scores were significantly higher for the experimental group compared to the control group. The experimental group washed their hands significantly more often when entering and leaving patients' rooms than the control group. Conclusion: Infection control education for family members of VRE patients was effective in improving knowledge and performance of infection control measures as well as improving the practice of hand washing. Further investigation is needed on the effects of infection control education for families on the actual VRE colonization and/or infection rate.

Anomalous Behavior of the Ethyl Group in the Aminolysis of S-Phenyl Acetate with Benzylamine in Acetonitrile

  • Lee, Ik-Choon;Lee, Hai-Whang;Lee, Byung-Choon;Choi, Jin-Heui
    • Bulletin of the Korean Chemical Society
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    • v.23 no.2
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    • pp.201-204
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    • 2002
  • The rates of the aminolysis of S-phenyl substituted-acetate series $(RC(=O)SC_6H_4Z$, with R=Me, Et, i-Pr, t-Bu and Bn) with benzylamines $(XC_6H_4CH_2NH_2)$ are not correlated simply with the Taft's polar $({\sigma}^{\ast})$ and/or steric effect constants $(E_s)$ of the substituents due to abnormally enhanced rate of the substrate with R=Et. Furthermore, the cross-interaction constant, ${\rho}x_z$ , is the largest with R=Et. These anomalous behaviors can only be explained by invoking the vicinal bond $({\sigma})$-antibond $({\sigma}^{\ast})$ charge transfer interaction between C-$C{\alpha}$ and C-S bonds. In the tetrahedral zwitterionic intermediate, $T^{\pm}$ , formed with R=Et the vicinal ${\sigma}_{c-c}-{\sigma}^{\ast}_{c-s}$ delocalization is the strongest with an optimum antiperiplanar arrangement and a narrow energy gap, ${\Delta}{\varepsilon}={\varepsilon}_{{\sigma}^{\ast}}-{\varepsilon}_{\sigma}$. Due to this charge transfer interaction, the stability of the intermediate increases (with the concomitant increase in the equilibrium constant K (= $k_a/k_{-a}$)) and also the leaving ability of the thiophenolate leaving group increases (and hence $k_b$ increases) so that the overall rate, $k_n\;=\;Kk_b$, is strongly enhanced. Theoretical support is provided by the natural bond orbital (NBO) analyses at the B3LYP/6-31+$G^{\ast}$ level. The anomaly exhibited by R=Et attests to the stepwise reaction mechanism in which the leaving group departure is rate limiting.

Kinetics and Mechanism of Pyridinolyses of Ethyl Methyl and Ethyl Propyl Chlorothiophosphates in Acetonitrile

  • Barai, Hasi Rani;Lee, Hai Whang
    • Bulletin of the Korean Chemical Society
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    • v.34 no.11
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    • pp.3372-3376
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    • 2013
  • The kinetic studies on the reactions of ethyl methyl (2) and ethyl propyl (4) chlorothiophosphates with X-pyridines have been carried out in acetonitrile at $35.0^{\circ}C$. The free energy correlations with X show biphasic concave upwards with a break point at X = H (2) and 3-Ph (4), respectively. A stepwise mechanism with a rate-limiting leaving group expulsion from the intermediate is proposed based on the magnitudes of selectivity parameters for both substrates. The considerably large values of ${\beta}_X$ = 1.50(2) and 1.44(4) with strongly basic pyridines and relatively small values of ${\beta}_X$ = 0.43(2) and 0.36(4) with weakly basic pyridines are interpreted as a change of the attacking direction of the X-pyridines from a frontside to a backside attack toward the chloride leaving group.

Application of the Extended Grunwald-Winstein Equation to Solvolyses of n-Propyl Fluoroformate and a Consideration of Leaving Group Effects

  • Seong, Mi-Hye;Kyong, Jin-Burm;Kim, Dong-Kook;Kevill, Dennis N.
    • Bulletin of the Korean Chemical Society
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    • v.29 no.9
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    • pp.1747-1751
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    • 2008
  • Reactions of n-propyl fluoroformate in a variety of pure and binary solvents have been studied at 40.0 {^{\circ}C}. The extended (two-term) Grunwald-Winstein equation has been applied to the specific rates of solvolysis of npropyl fluoroformate. The sensitivities (l = 1.80 ${\pm}$ 0.17 and m = 0.96 ${\pm}$ 0.10) to changes in solvent nucleophilicity and solvent ionizing power and the $k_F/k_{Cl}$ values are similar to those for solvolyses of n-octyl fluoroformate over the full range of solvents, suggesting that the addition step of an addition-elimination mechanism is ratedetermining. These observations are also compared with those previously reported for the corresponding chloroformate and fluoroformate esters.

MNDO Studies on the Gas-Phase S$_N$2 Reaction$^*$

  • Lee Ikchoon;Lee Bon-Su;Song Chang Hyun
    • Bulletin of the Korean Chemical Society
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    • v.6 no.4
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    • pp.191-196
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    • 1985
  • The MNDO was found to be the most reliable semi-empirical SCF-MO method for the studies of $S_N2$ reactions involving anion and neutral molecule. The results of our MNDO calculations on the $S_N2$ reactions of $CH_3X$ + $Y^-$$CH_3Y$ + X- where X = H, F, Cl, CN, $CH_3$, and Y = F, $CH_3$ showed that the order of the leaving group ability is the reverse of the order of proton affinities. It was also found that there is no symbiosis involved in the SN2 transition state and the departure of the leaving group is relatively late in contrast to the early bond formation of the nucleophile. The Marcus equation was found to apply to the MNDO barriers and energy changes.

Development of Remote Sensing Reflectance and Water Leaving Radiance Models for Ocean Color Remote Sensing Technique (해색 원격탐사를 위한 원격반사도 및 수출광 모델의 개발)

  • 안유환
    • Korean Journal of Remote Sensing
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    • v.16 no.3
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    • pp.243-260
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    • 2000
  • Ocean remote sensing reflectance of just above water level was modeled using inherent optical properties of seawater contents, total absorption (a) and backscattering(bb) coefficients ($R_{rs}$=0.046 $b_b$/(a+$b_b$). This modeling was based on the specific absorption and backscattering coefficients of 5 optically active seawater components; phytoplankton pigments, non-chlorophyllous suspended particles, dissolved organic matters, heterotrophic microorganisms, and the other unknown particle components. Simulated remote sensing reflectance($R_{rs}$) and water leaving radiance(Lw) spectra were well agreed with in-situ measurements obtained using a bi-directional fields remote spectrometer in coastal waters and open ocean. $R_{rs}$ values in SeaWiFS bands from the model were analyzed to develop 2-band ratio ocean color chlorophyll with those observed insitu. Also, chlorophyll algorithm based on remote reflectance developed in this study fell in those obtained by a SeaBAM working group. The model algorithms were examined and compared with those observed insitu. Also, chlorophyll algorithm based on remote reflectance developed in this study fell in those obtained by a SeaBAM working group. The remote reflectance model will be very helpful to understand the variation of water leaving radiances caused by the various components in the seawater, and to develop new ocean color algorithm for CASE-II water using neural network method or other analytical method, and in the model of fine atmospheric signal correction.

Bidirectional Factor of Water Leaving Radiance for Geostationary Orbit (정지궤도를 위한 해면방사휘도$(L_w)$의 양방향 계수 (bidirectional factor) 평가 연구)

  • Park, Jin-Kyu;Han, Hee-Jeong;Mun, Jeong-Eon;Yang, Chan-Su;Ahn, Yu-Hwan
    • Proceedings of KOSOMES biannual meeting
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    • 2006.11a
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    • pp.181-186
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    • 2006
  • Geostationary Orbit satellite, unlike other sun-synchronous polar-orbit satellites, will be able to take a picture of a large region several times a day (almost with everyone hour interval). For geostationary satellite, the target region is fixed though the location of sun is changed always. However, Sun-synchronous polar-orbit satellites able to take a picture of target region same time a everyday. Thus Ocean signal is almost same. Accordingly, the ocean signal of a given target point is largely dependent on time. In other words, the ocean signal detected by geostationary satellite sensor must translate to the signal of target when both sun and satellite are located in nadir, using another correction model. This correction is performed with a standardization of signal throughout relative geometric relationship among satellite-sun-target points. This relative ratio called bidirectional factor. To find relationship between time and $[L_w]_N$/Bidirectional Factor differences, we are calculate solar position, geometry parameters. And reflectance, total radiance at the top of atmosphere(). And water leaving radiance, normalized water leaving radiance. And calculate bidirectional factor, that is the ratio of $[L_w]_N$ between target region and aiming the point. Then, we can make the bidirectional factor lookup table for one year imaging. So, we suggested for necessary to simulation experiment bidirectional factor in more various condition(wavelength and ocean/air condition).

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The Analysis on the Determinations Factors of Container Port Competitiveness (컨테이너 항만경쟁력 결정요인 분석)

  • Lee, Ki-Tae;Baek, In-Hum
    • Journal of Fisheries and Marine Sciences Education
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    • v.27 no.1
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    • pp.262-272
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    • 2015
  • The aim of this study is to analysis factors that determine the competitiveness of container ports using the KJ and AHP methods. For this, 54 detailed attributing factors were identified both by previous studies and port users. 24 attributing factors were identified by a group of port experts. also, These were grouped 18 detailed attributing factors into 6 attributing factors by a group of port experts using the KJ method. These were made into a model of hierarchical structure with 3 levels, taking 1 goal factor, 6 evaluation factors and 18 detailed evaluation factors. The collected date of questionnaires were analyzed by a group of port experts using the AHP method. The analysis result of the evaluation factors in container port shows that port cargo volume is the most important factor, followed by port location, port cost, port service, port facility and port management. The analysis results of detailed evaluation factors in container port shows that import and export cargo volume is the most important factor, followed by transshipment cargo volume, distance from main trunk, cargo handling cost, distance from the point of importing and exporting, speediness of cargo handling, stability of cargo handling, vessel/cargo cost in port entry and leaving, punctuality in port entry and leaving, number and length of berth, collateral service cost, terminal area, hinterland accessibility, ability of terminal operation company, front depth of berth, etc.

BIDIRECTIONAL FACTOR OF WATER LEAVING RADIANCE FOR GOCI

  • Han, Hee-Jeong;Ahn, Yu-Hwan;Ryu, Joo-Hyung
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.79-81
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    • 2006
  • Geostationary ocean satellite, unlike other sun-synchronous polar-orbit satellites, will be able to take a picture of a large region several times a day (almost with every one hour interval). For geostationary satellite, the target region is fixed though the location of sun is changed always. Thus, the ocean signal of a given target point is largely dependent on time. In other words, the ocean signal detected by geostationary satellite sensor must translate to the signal of target when both sun and satellite are located in nadir, using another correction model. This correction is performed with a standardization of signal throughout relative geometric relationship among satellite - sun - target points. One signal value of a selected pixel point of the target region of Geostationary Ocean Colour Imager (GOCI) would be set up as a standard, and the ratio of all remained pixel point can be calculated. This relative ratio called bidirectional factor, the result of modelling of spatiotemporal variation of bidirectional factor is shown.

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MO Theoretical Studies on the Benzylic and Resonance Shunt Effects

  • Ikchoon Lee;Jeong Ki Cho;Chang Kon Kim
    • Bulletin of the Korean Chemical Society
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    • v.12 no.2
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    • pp.182-188
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    • 1991
  • The reactions of aniline with benzyl and phenacyl compounds are studied by the AM1 method. Two types of modeling were adopted: Cation-neutral, in which a proton is attached to the leaving group F and anion-neutral model, in which aniline was replaced by phenoxide with Cl as the leaving group. The cation-neutral model represented the reactvery well, reproducing the various solution-phase experimental results. In the benzyl system, the ${\pi}$-electrons of the two rings (X-ring in the nucleophile and Y-ring in the substrate) interact conjugatively in the transition state (TS) resulting in a bond contraction of the $C_{\alpha}-C_{Y1}$ bond (benzylic effect), whereas in the phenacyl system the ${\pi}$ electrons of the X-ring delocalizes more efficiently into the carbonyl group than into the Y-ring (resonance shunt effect) with a bond contraction of the $C_{\alpha}-C_{\beta}$ bond. The bond contraction in the benzylic effect was substantially greater than that in the resonance shunt effect. The TS was rather loose for benzyl while it was tighter for phenacyl system. Various bond length changes with substituents in the TS were, however, found to be irregular.