• Title/Summary/Keyword: VS mechanism

Search Result 288, Processing Time 0.025 seconds

An Analysis on the Issue of the College Admission Systems: Comparison of Parental Income Level of College Entrants of Early and Regular Admissions (대입제도 쟁점분석: 수시와 정시 입학생들의 소득수준 비교 분석)

  • Lee, Kwanghyun;Kwon, Yongjae
    • The Journal of the Korea Contents Association
    • /
    • v.21 no.12
    • /
    • pp.107-118
    • /
    • 2021
  • One of the debates regarding the college admission systems is about which admissions screening works as a mechanism for social mobility, between early and regular admissions. This study attempted to contribute to related discussions by analyzing the income level of college admissions students according to the admissions screening (early vs. regular admissions) using data from the third year survey of the Korean Education & Employment Panel II (KEEP II). Analyzing the dataset, we found that parental income was almost the same between students admitted from early and regular admissions. To be specific, average monthly parental income was 586.4 million Korean Won for students admitted from early admission while it was 585.4 million Korean Won for those admitted from regular admission, which means that the difference between the two was neither practically nor statistically significant. Applying the chi-square test, we tested whether the relationship between parental income and types of college admissions and found no statistical significance. Finally, categorizing colleges where students are admitted by ranking, we compared parental incomes among students. We found that parental income was higher for top-ranked universities, and that parental income was higher for students admitted from early admission. We concluded that early admission can possibly be an admission system for "well-offs" between the two, and that early admission may not be working as a pathway to facilitate social mobility compared to the regular admissions.

An Appreciation of Functional Role of Macrophage in the Acute Lung Injury in the Neutropenic Rat. (호중구 감소증을 보이는 백서의 급성폐손상에서 대식세포의 기능적 역할)

  • Kim, Yong-Hoon;Ki, Sin-Young;Im, Keon-Il;Moon, Seung-Hyug;Cheong, Seung-Whan;Kim, Hyeon-Tae;Uh, Soo-Taek;Park, Choon-Sik;Jin, Byung-Won
    • Tuberculosis and Respiratory Diseases
    • /
    • v.44 no.2
    • /
    • pp.379-390
    • /
    • 1997
  • Background : It has long been suggested that neutrophils and their products are implicated as the central mediators of the acute lung injuries. Contrary to the dominant role of neutrophils in ARDS, many cases of ARDS has occurred in the setting of severe neutropenia without pulmonary neutrophil infiltration. Therefore it is certain that effector cell(s) other than neutrophil play an important role in the pathogenesis of ARDS. This experiment was performed to define the mechanism of ARDS in the setting of neutropenia, 1) by comparing the severity of endotoxin-induced lung injury, 2) by measurement of hydrogen peroxide production and cytokine concentration in the bronchoalveolar lavage cells and fluids obtained from different rats with and without cyclophosphamide-pretreatment. Method : The male Sprague-Dawleys were divided into the normal control (NC)-, endotoxin (ETX)-, and cyclophosphamide (CPA)-group in which neutropenia was induced by injecting cyclophosphamide intraperitoneally. Acute lung injury was evoked by injecting lipopolysaccharide (LPS) into a tail vein. The bronchoalveolar lavage (BAL) was performed at 3 and 6 hour after administration of LPS to measure the change of cell counts and concentrations of protein and cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). Hydrogen peroxide (HPO) production from BAL cells was measured at 6 hour after LPS administration by phenol red microassay with and without zymosan stimulation. Results : The results were as follows. A change of leukocyte counts in the peripheral blood after treatment with CPA : More than 95% of total leukocytes and neutrophils were reduced after CPA administration, resulting in severe neutropenia. A change of BAL cells : In the ETX-group, the number of total cells (p < 0.01) and of macrophage and neutrophil (p < 0.05) were increased at 3 and 6 hour after LPS administration compared to those of NC-group. In the CPA-group, the number of total leukocyte and macrophage were not changed after LPS administration, but neutrophil counts were significantly reduced and it took part in less than 0.1% of total BAL cells (p < 0.01 vs NC-group). BAL cells in this group were almost all macrophages (99.7%). A change of protein concentration in the BALF : In the ETX-group, protein concentration was increased at 3 hour and was more increased at 6 hour after LPS administration (p < 0.05 and < 0.01 vs NC-group, respectively). In the CPA-group, it was also significantly elevated at 3 hour after LPS administration (p < 0.05 vs NC-group), but the value was statistically not different from that of ETX-group. The value measured at 6 hour after LPS administration in the CPA-group became lower than that of ETX-group (p < 0.05), but showed still a higher value compared to that of NC-group (p < 0.05). A change of cytokine concentration in the BALF : TNF -alpha and IL-6 were elevated in the ETX - and CPA-group compared to those of NC-group at both time intervals. There was no statistical difference in the values of both cytokines between the ETX- and CPA-groups. Measurement of hydrogen peroxide production from BAL cells : There was no intergroup difference of HPO production from resting cells. HPO production after incubation with opsonized zymosan was significantly elevated in all groups. The percent increment of HPO production was highest in the ETX-group (89.0%, p < 0.0008 vs NC-group), and was 42.85 in the CPA-group (p = 0.003 vs NC-group ). Conclusion : Acute lung injury in the setting of neutropenia might be caused by functional activation of resident alveolar macrophages.

  • PDF

Nucleophilic Substitutions at a Carbonyl Carbon Atom (ⅩⅡ). Solvolysis of Methylchloroformate and Its Thioanalogues in $CH_3CN-H_2O$ and $CH_3COCH_3-H_2$ Mixtures (카르보닐탄소원자의 친핵성 치환반응 (제 12 보).아세토니트릴-물 및 아세톤-물 혼합용 매속에서 메틸클로로훠메이트와 그 티오유도체들의 가용매분해반응에 관한 연구)

  • Sangmoo La;Kyeong Shin Koh;Ikchoon Lee
    • Journal of the Korean Chemical Society
    • /
    • v.24 no.1
    • /
    • pp.8-14
    • /
    • 1980
  • Solvolysis rate constants for methylchloroformate, $CH_3O$(CO)Cl, methylthiono-chloroformate, $CH_3O$(CS)Cl, and methylthiolchloroformate, $CH_3S$(CO)Cl, have been determined conductometrically in acetone-water and acetonitrile-water mixtures, and activation parameters, ${\Delta}H^{\neq}$ and ${\Delta}S^{\neq}$, have been derived. Results show that in water-rich regions the order of rate increases as $$CH_3O(CO)Cl while in dipolar aprotic solvent-rich region this order reverses. The plots of log k vs. solvent parameters, Y, $\frac{D-1}{2D+1}$ and log($H_2$) show that the order of rate increase in water-rich region is the results of increase in $S_N1$ character. It is concluded that $CH_3S$(CO)Cl solvolyzes via $S_N1$ mechanism whereas $CH_3O$(CO)Cl reacts via $S_N2$ and $CH_3O$(CS)Cl via intermediate mechanism in water-rich region.

  • PDF

The Elution Behaviors of Some Metal-2-Hydroxy-arylazopyrazolone Chelates by Reversed Phase Liquid Chromatography (II) (역상 액체 크로마토그래피에 의한 금속-2-hydroxy-arylazopyrazolone 유도체 킬레이트의 용리거동에 관한 연구 (II))

  • Lee, Won;Kim, In-Whan;Kang, Chang-Hee;Kim, Eun-Kyung
    • Analytical Science and Technology
    • /
    • v.7 no.3
    • /
    • pp.379-386
    • /
    • 1994
  • The elution behaviors in reversed-phase liquid chromatography were investigated thermodynamically for 2-hydroxy-arylazopyrazolone chelates with Ni(II), Cu(II), Co(III), Cr(III) on Novapak $C_{18}$ column. There was a good linear dependence of the capacity factor(k') on the variations of column temperature in van't Hoff plot. From this result, it was confirmed that the retention mechanism of these chelates in the reversed phase liquid chromatography system was invariant under the condition of various temperatures. For the most cases of the chelates studied, the dependence of capacity factor(1n k') on enthalpy$(-{\Delta}H)^{\circ}$, calculated by van't Hoff plot showed a good linearity(r=0.980~0.999) except [Pm(2-OH_(5-Cl)PaPz](r=0.787) and also the compensation temperatures(${\beta}$) showed constant values. The range of compensation temperature values calculated from the slope of $-{\Delta}H^{\circ}$ vs 1n k' plots was 374.3~806.9K. It was suggested that the retention of metal-2-hydroxy-arylazopyrazolone chelates in the reversed phase liquid chromatography system was largely affected by the hydrophobic effect.

  • PDF

Cytogenetic Analysis of Korean Shinner, Coreoleuciscus splendidus (Cyprinidae) (쉬리, Coreoleuciscus splendidus (Cyprinidae)의 세포유전학적 연구)

  • Kim, Dong-Soo;Song, Ha-Yeun;Bang, In-Chul;Nam, Yoon-Kwon
    • Journal of Aquaculture
    • /
    • v.20 no.2
    • /
    • pp.140-143
    • /
    • 2007
  • Cytogenetic analyses of an endemic species, Coreoleuciscus splendidus (Cyprinidae) was performed including erythrocyte measurement, chromosome count and karyotyping, nucleolar organizing region (NOR) banding and flow cytometric analysis of genome size. C. splendidus had the same modal chromosome number of 2n = 48 between sexes, however, displayed a sex-related dimorphism in their chromosome karyotypes. Males represented a pair of heteromorphic chromosomes which couldn‘t be seen in any female individuals, indicating that the sex determination mechanism of this species should be a typical XX-XY based male heterogamety (female=10M+6SM+8A+XX vs male=10M+6SM+8A+XY). Other cytogenetic features such as Ag-NORs located in a pair of acrocentric chromosomes, estimated nuclear volume ($28{\mu}m^3$) and cellular DNA content (2.4 pg/cell) suggest that genetic recombination might be the main driving force responsible for the evolution of this species rather than the polyploidy-based evolutionary process as in many other Cyprinidae species.

Role of Blood Flow vs. $O_{2}$ Consumption in Nicotinamide-induced Increase $pO_{2}$ in a Murine Tumor (Nicotinamide에 의한 종양내 산소 분압의 증가에 있어서 혈류 또는 산소 소모의 역할)

  • Lee Intae;Demhartner Thomas J.;Cho Moon-June
    • Radiation Oncology Journal
    • /
    • v.12 no.1
    • /
    • pp.17-25
    • /
    • 1994
  • We evaluated the effect of nicotinamide on cellular $O_{2}$ consumption and metabolic status i.e., adenylate phosphates and $NAD^{+}$in-vitro, and changes in blood flow in-vivo, to determine whether changes in cellular metabolism or increased oxygen availability, was responsible for increased tumor oxygenation. Thirty min, pre-incubation of cells with$\∼$4mM (= 500mg/kg) nicotinamide resulted in no change in cellular $O_{2}$ consumption. Similarly neither the adenylate Phosphates nor the cellular $NAD^{+}$levels were altered in the presence of $\∼$4mM nicontinamide. In-vivo, nicotinamide (500mg/kg) increased $O_{2}$ availability as estimated by changes in relative tumor blood flow (RBC flux). The changes in RBC flux measured by the laser Doppler method, were tumor volume dependent and increased from$\∼$35$ \% $ in$\∼$ 150$mm_{3}$tumors to$\∼$~75$ \% $ in$\∼$500$mm^{3}$ tumors. In conclusion, these observations indicate a reduction in local tissue $O_{2}$ consumption is not a mechanism of improved tumor oxygenation by nicotinamide in FSa II murine tumor model. The primary mechanism of increased $pO_{2}$ appears to be an increased local tumor blood flow.

  • PDF

The Effect of Regulatory Focus on the Link Between Purchase Behavior and Redemption Behavior

  • Kim, Ji Yoon
    • Asia Marketing Journal
    • /
    • v.15 no.4
    • /
    • pp.51-60
    • /
    • 2014
  • Previous research on loyalty program has verified the factors that influence redemption behavior and the understanding of the mechanism of redemption behavior with academic and practical implications. However, these research has not proven boundary conditions in which the phenomena can be strengthened or weakened- that is, the moderating effect remains unclear. The inclusion of moderating variables can provide a more extensive understanding of the mechanism of this behavior from academic and managerial perspectives alike. Therefore, this current research proposes regulatory focus as a moderating variable, which has received scarce attention in the study of loyalty program behavior, especially individual characteristic variables that, in turn, affect the consumers' purchasing behavior in various ways. Previous research on consumer decision making investigates the differential role of regulatory focus as a series of stages. Regulatory focus theory posits that people depend on the two types of regulatory focus when pursuing goals: promotion focus vs. prevention focus. The former induces tendencies to recognize a goal as a hope and ideal, as something that satisfies the need for accomplishment, and to be sensitive to the presence of a positive outcome of the match and to match the pursuit of goals. On the other hand, the latter tends to regard a goal as the responsibility or obligation to achieve the goal, has a tendency to avoid failure to meet a target, and is sensitive to the presence of the negative consequences that do not reach the target. The following propositions are suggested: 1) The effect of higher accumulation effort level on delaying point redemption speed will be relatively more pronounced for customers with prevention focus. 2) The effect of higher accumulation effort level on large redemption unit size will be relatively more pronounced for customers with prevention focus. 3) The effect of higher accumulation effort level on hedonic redemption ratio will be relatively more pronounced for customers with promotion focus. Therefore, this research provides a moderating variable that has the potential to be used as a reference for market segmentation and affects the relationship between point accumulation effort and three sides of point redemption behavior. On this basis, the direction for the future research on this issue is recommended. Future research could verify these propositions conducting a survey of customers' propensity of regulatory focus in conjunction with the history of the loyalty program of data. This would provide a more realistic effect on the usage behavior of loyalty program consumers by providing useful implications for both marketing practitioners and researchers.

  • PDF

Spatio-temporal Fluctuations of Size-structured Phytoplankton over an Annual Cycle in the Youngsan Lake

  • Song, Eun-Sook;Shin, Yong-Sik
    • Korean Journal of Ecology and Environment
    • /
    • v.41 no.4
    • /
    • pp.530-540
    • /
    • 2008
  • The temporal and spatial variations of size-structured phytoplankton dynamics in Youngsan Lake were investigated to explore potential mechanims controlling the dynamics in the Youngsan Lake. Field data were collected monthly from February to October, 2003 at 6 stations along the axis of Youngsan Lake. In this study, phytoplankton (chlorophyll $\alpha$) were categorized into three size classes: micro-size ($>20{\mu}m$), nano-size ($2{\sim}20{\mu}m$) and pico-size ($<20{\mu}m$). Water temperature, light attenuation coefficients, PAR (photosynthetically active radiation) and suspended solids were measured to analyze relationship between physical-chemical properties and size structure of phytoplankton. Phytoplankton blooms developed during March, July and October in the upper region of the main stem whereas small-scaled spring bloom was observed in the lower region. The scales of phytoplankton blooms were higher in the upper regions than the lower region and blooms were predominated by micro-size class in upper region but predominated by nano-size class in lower region. Growth of size-structured phytoplankton appeared to be controlled by rather light availability than temperature-dependant metabolisms in the system. Phytoplankton growth may be also supported by ambient nutrients available in the water column from analyses of chlorophyll $\alpha$ vs. nutrient concentrations including nitrite+nitrate and orthophosphate. Growth of nano-sized phytoplankton alone appeared to be supported by orthophosphate as well as nitrite+nitrate indicating that response of phytoplankton to nutrient inputs may be size-dependent.

AEP Prediction of a Wind Farm in Complex Terrain - WindPRO Vs. WindSim (복잡지형에 위치한 풍력발전단지의 연간발전량 예측 비교 연구)

  • Woo, Jae-Kyoon;Kim, Hyeon-Gi;Kim, Byeong-Min;Gwon, Il-Han;Baek, In-Su;Yoo, Neung-Soo
    • Journal of the Korean Solar Energy Society
    • /
    • v.32 no.6
    • /
    • pp.1-10
    • /
    • 2012
  • The annual energy production of Gangwon wind farm was predicted for three consecutive years of 2007, 2008 and 2009 using commercial programs, WindPRO and WindSim which are known to be used the most for wind resource prediction in the world. The predictions from the linear code, WindPRO, were compared with both the actual energy prediction presented in the CDM (Clean Development Mechanism) monitoring report of the wind farm and also the predictions from the CFD code, WindSim. The results from WindPRO were close to the actual energy productions and the errors were within 11.8% unlike the expectation. The reason for the low prediction errors was found to be due to the fact that although the wind farm is located in highly complex terrain, the terrain steepness was smaller than a critical angle($21.8^{\circ}$) in front of the wind farm in the main wind direction. Therefore no flow separation was found to occur within the wind farm. The flow separation of the main wind was found to occur mostly behind the wind farm.

Effect of Alkali Metal Ions on Nucleophilic Substitution Reactions of 4-Nitrophenyl X-Substituted Benzoates with Alkali Metal Ethoxides in Anhydrous Ethanol

  • Seo, Jin-A;Kim, Song-I;Hong, Yeon-Ju;Um, Ik-Hwan
    • Bulletin of the Korean Chemical Society
    • /
    • v.31 no.2
    • /
    • pp.303-308
    • /
    • 2010
  • Pseudo-first-order rate constants ($k_{obsd}$) have been measured spectrophotometrically for nucleophilic substitution reactions of 4-nitrophenyl benzoate (5a), 4-nitrophenyl 4-methoxybenzoate (5b), and 4-nitrophenyl 4-hydroxybenzoate (5c) with alkali metal ethoxides, $EtO^-M^+$ ($M^+=Li^+$, $Na^+$ and $K^+$) in anhydrous ethanol (EtOH) at $25.0{\pm}0.1^{\circ}C$. The plots of $k_{obsd}$ vs. [$EtO^-M^+$] exhibit upward curvatures in all cases, indicating that $M^+$ ions catalyze the reactions and ionpaired $EtO^-M^+$ species are more reactive than dissociated $EtO^-$. Second-order rate constants for reactions with dissociated $EtO^-$ and ion-paired $EtO^-M^+$ (i.e., $k_{EtO^-}$ and $k_{EtO^-M^+}$, respectively) have been calculated from ion-pair treatment for the reactions of 5a and 5b. However, such ion-pair treatment has failed to determine $k_{EtO^-}$ and $k_{EtO^-M^+}$ values for the reactions of 5c. It has been concluded that reactions of 5a and 5b are catalyzed by one metal ion, which increases electrophilicity of the reaction center through coordination on the carbonyl oxygen. In contrast, reactions of 5c have been suggested to involve two metal ions, i.e., the one coordinated on the carbonyl oxygen increases the electrophilicity of the reaction center while the other one associated on the phenoxy oxygen decreases the charge repulsion between the anionic reagents (i.e., $EtO^-$ and deprotonated 5c). It has been found that the rate equation derived from the mechanism involving two metal ions fits nicely to the kinetic results obtained for the reactions of 5c.