• Restorative Dentistry and Endodontics
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• v.43 no.1
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• pp.11.1-11.10
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• 2018

Objectives: This study aimed to introduce the use of laser-induced breakdown spectroscopy (LIBS) for evaluation of the mineral content of root canal dentin, and to assess whether a correlation exists between LIBS and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) methods by comparing the effects of irrigation solutions on the mineral content change of root canal dentin. Materials and Methods: Forty teeth with a single root canal were decoronated and longitudinally sectioned to expose the canals. The root halves were divided into 4 groups (n = 10) according to the solution applied: group NaOCl, 5.25% sodium hypochlorite (NaOCl) for 1 hour; group EDTA, 17% ethylenediaminetetraacetic acid (EDTA) for 2 minutes; group NaOCl+EDTA, 5.25% NaOCl for 1 hour and 17% EDTA for 2 minutes; a control group. Each root half belonging to the same root was evaluated for mineral content with either LIBS or SEM/EDS methods. The data were analyzed statistically. Results: In groups NaOCl and NaOCl+EDTA, the calcium (Ca)/phosphorus (P) ratio decreased while the sodium (Na) level increased compared with the other groups (p < 0.05). The magnesium (Mg) level changes were not significant among the groups. A significant positive correlation was found between the results of LIBS and SEM/EDS analyses (r = 0.84, p < 0.001). Conclusions: Treatment with NaOCl for 1 hour altered the mineral content of dentin, while EDTA application for 2 minutes had no effect on the elemental composition. The LIBS method proved to be reliable while providing data for the elemental composition of root canal dentin.

• Journal of Korean Society for Geospatial Information Science
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• v.4 no.2 s.8
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• pp.63-77
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• 1996

This study suggests that experts' group decision support system (Experts'GDSS) should be helpful to solve specific planning/design problems. Dealing with AHP (Analytic Hierarchical Process), as a group decision model, maximal covering model, as a facility allocation model, and GIS (Geographic Information System; ARC/INFO in this study), as a spatial representation model, this study seeks to examine the implication of GDSS (Group Decision Support System) in the housing facility allocation. The results of this study clearly demonstrated that experts' GDSS acted its positive role, systematically providing the relative weights among the planning variables and objectives. Among different expert groups (e.g., planners, scholars, and public administrators), this study showed that there were certain differences in their decision structures, which generated different solutions in facility allocation. The further study, however, remains to investigate the more systematic implementation of GDSS in planning problems; for example, reducing the conflicts between different groups with different purposes.

• Environmental Engineering Research
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• v.14 no.2
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• pp.81-87
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• 2009

The decomposition of antibiotics (cefaclor) by gamma irradiation in aqueous solutions was experimentally evaluated. To obtain a mutual interaction between two factors (antibiotics concentrations and radiation doses) and to optimize these factors during the process, experimental design and statistical analysis were employed. The decomposition capability of the gamma radiation was also mathematically described as a function of cefaclor concentration and gamma-ray dose using the statistical analysis. The results showed that the cefaclor concentration ($X_1$) in the response $Y_1$ (Reduction of cefaclor concentration) and gamma-ray dose ($X_2$) in the response $Y_2$ (Removal efficiency (%) of cefaclor concentration) exhibited a significantly positive effect, whereas gamma-ray dose ($X_2$) in the response $Y_1$ showed a significantly negative effect. The estimated ridge of maximum responses and optimal conditions for $Y_1$:($X_1$,$X_2$)=(25 mg/L, 350 Gy) and $Y_2$:($X_1$,$X_2$)=(21 mg/L, 565 Gy) using canonical analysis were 4.37 mg/L of reduction of cefaclor concentration and 98.35% of removal efficiency of cefaclor concentration, respectively. The measurement values agreed well with the predicted ones, thereby confirming the suitability of the model for $Y_1$ and $Y_2$ and the success of the experimental design in optimizing the conditions of the gamma irradiation process.

• Analytical Science and Technology
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• v.8 no.2
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• pp.107-116
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• 1995

The critical micelle concentration(CMC) of CTAB was determined with changes in absorbance at 202nm band of 4-biphenyl acetate($BPA^-$). With $BPA^-$ as a probe, the effect of temperature on CMC of CTAB has been observed between $30^{\circ}C{\sim}70^{\circ}C$. In this range of temperature the values of CMC are $1.18{\times}10^{-4}{\sim}2.02{\times}10^{-4}M$. The free energy(${\Delta}G^{\circ}m$) and enthalpy(${\Delta}H^{\circ}m$)for the micellization of CTAB was negative and the entropy(${\Delta}S^{\circ}m$) was a large positive value. The micellization of CTAB is considered as a spontaneous process and to involve a phase transition. The orientational binding of 4-biphenyl acetate anion to the CTAB micelle interface has been studied with $300MHz\;H^1-NMR$ data. The change in chemical shift of proton in CTAB as well as those of the protons in $BPA^-$ have been investigated by increasing the mole fraction of the anion in the mixed solutions. The changes in chemical shift with increasing mole fraction of anion($BPA^-$) indicate the formation of mixed micelle between CTAB and $BPA^-$. The changes in chemical shifts of methylene protons in CTAB, demonstrate the penetration of $BPA^-$ into the palisade layer of the CTAB micelle.

• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.219-225
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• 2006

The rabbit pyrogen test and Limulus amoebocyte lysate (LAL) assay have been used to detect endotoxins present in vaccines. Currently, the rabbit pyrogen test is used to detect endotoxins in hepatitis B (HB) vaccines, even though the HB surface protein, which is the active ingredient, is overexpressed in and purified from eukaryotic cells that lack these endotoxins. Although the LAL clot assay is sensitive and reliable and can be used to replace the rabbit pyrogen test, its reaction is limited by the lack of responsiveness to the Gram-positive bacterial components. Furthermore, aluminum hydroxide in the HB vaccine can interfere with the LAL assay. In contrast, macrophages can detect the endotoxin as well as other pyrogens, and secrete $TNF-{\alpha}$. Therefore, this study was undertaken to examine the possibility of replacing the animal tests with a more efficient $TNF-{\alpha}$ secretion assay. With this in mind, we determined if aluminum hydroxide in the HB vaccines affects the $TNF-{\alpha}$ secretion assay. HB vaccines and the HB protein solutions spiked with lipopolysaccharide (LPS) produced the same level of dose-dependent $TNF{\alpha}$ secretion and temperature increase in rabbits, indicating that aluminum hydroxide in the HB vaccine does not interfere with the pyrogenic response in rabbits, nor does it interfere with $TNF-{\alpha}$ secretion. In addition, the $TNF-{\alpha}$ assay was found to be more sensitive than the LAL assay, and correlated well with the pyrogen test and the LAL assay. These results suggest that the $TNF-{\alpha}$ assay in RAW264.7 cells is a good substitute for the current pyrogen assays that are used for detecting LPS in HB vaccines as well as in other vaccines containing aluminum.

• Journal of Engineering Education Research
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• v.23 no.1
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• pp.10-25
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• 2020

This study was conducted to identify the causes of academic weakness and to find the ways to cope with it for the students majoring in science and engineering at the top university in Korea. For this purpose, a questionnaire was conducted for students who experienced academic warning and poor academic performance at A university, and a total of 207 students responded. The results were divided into two groups majoring in science and engineering or not and the characteristics and differences of each group were analyzed. In addition, in-depth interviews were conducted with five students who had experienced academic warning and poor academic performance. As a result, the group majoring in science and engineering had a relatively low level of difficulty in forming interpersonal relationships and relatively high degree of participation of activities in their departments. The group majoring in science and engineering have a tendency to choose careers that are connected with their majors, and therefore, their response was relatively low due to lack of career goals. However, the group majoring in science and engineering had difficulty in academic performance due to the difference in basic courses and the level of recognition about self-learning strategy needed for university study was relatively low compared with the group majoring in non-science and engineering. When they experienced academic problems, they said that their interest, support, and positive feedback from professors helped them recover their motivation and continue their studies. Through these results, it was confirmed that intervention and support are needed considering the academic situation and characteristics of the students majoring in science and engineering.

• Molecules and Cells
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• v.40 no.10
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• pp.787-795
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• 2017

Avoiding ingestion of excessively salty food is essential for cation homeostasis that underlies various physiological processes in organisms. The molecular and cellular basis of the aversive salt taste, however, remains elusive. Through a behavioral reverse genetic screening, we discover that feeding suppression by $Na^+$-rich food requires Ionotropic Receptor 76b (Ir76b) in Drosophila labellar gustatory receptor neurons (GRNs). Concentrated sodium solutions with various anions caused feeding suppression dependent on Ir76b. Feeding aversion to caffeine and high concentrations of divalent cations and sorbitol was unimpaired in Ir76b-deficient animals, indicating sensory specificity of Ir76b-dependent $Na^+$ detection and the irrelevance of hyperosmolarity-driven mechanosensation to Ir76b-mediated feeding aversion. Ir76b-dependent $Na^+$-sensing GRNs in both L- and s-bristles are required for repulsion as opposed to the previous report where the L-bristle GRNs direct only low-$Na^+$ attraction. Our work extends the physiological implications of Ir76b from low-$Na^+$ attraction to high-$Na^+$ aversion, prompting further investigation of the physiological mechanisms that modulate two competing components of $Na^+$-evoked gustation coded in heterogeneous Ir76b-positive GRNs.

• The Korean Journal of Cytopathology
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• v.18 no.1
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• pp.29-35
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• 2007

This study purposed to evaluate a $CellPrep^{(R)}$ (CP) of liquid-based cytology (LBC) to search for a less expensive and automated alternative cytologic preparation technique applicable to usually encountered cytologic specimens. Cervicovaginal direct-to-vial split samples from 457 gynecologic patients, 40 body fluid samples, and 34 urine samples were processed with the CP technique and the results were compared with those of currently used $ThinPrep^{(R)}$ (TP) method. Both CP and TP methods provide evenly distributed thin layers of cells with little cellular overlaps or significant obscuring elements in most of cases. Staining quality of both preparations showed a little difference due to the difference of fixative solutions without significant distractions in cytologic interpretation. On the supposition that TP was a gold standard, sensitivity, specificity, positive predictive value, and negative predictive value of CP cytology were 89%, 98%, 86%, and 99% in the cervicovaginal smear, 89%, 82%, 80%, and 90% in body fluid, and all of these values were 100% in urine samples. To testify the availability of immunohistochemistry on CP preparations, cytokeratin, vimentin, and Ki-67 were applied on body fluid specimens, and all of these antibodies were specifically stained on targeted cells. Conclusively, the CP method gave comparable results to those of TP in terms of smear quality and cytologic diagnostic evaluation, and was available on immunohistochemistry. The CP method could offer a cost-effective and automated alternative to the current expensive techniques of liquid-based cytology on popular cytologic materials including cervicovaginal, body fluid, and urine specimens.

• The Korean Journal of Food And Nutrition
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• v.31 no.3
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• pp.328-334
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• 2018

The purpose of this study was to examine the effects of Maca water and/or ethanol extract on the nitric oxide (NO) production in human umbilical vein endothelial cells HUVAC and on erectile dysfunction in rats. Maca was extracted due to both solutions, which are water and ethanol. Each Maca extract was applied to HUVAC, and NO production was checked. Additionally, three different dosages (250, 500 and 1,000 mg/kg) of Maca ethanol extract was administered to Sprague-Dawley rats for 4 weeks. All rats were sacrificed and each sample was collected for analysis. The control rats received only the saline vehicle. The NO production of HUVAC was significantly increased by domestic and homemade Maca water extracted at $60^{\circ}C$ group. Both NO generation and testosterone release were not influenced due to the oral administration of Maca. In the EtOH group rats, the number of sperm was reduced compared to that of the control group. All Maca groups had a high number of sperm and each sperm count had increased as a result of the Maca extract dose. The results of this research suggest that Maca has a positive effect on male erectile dysfunction, which need to be examined further in future studies.

• Journal of Information Management
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• v.42 no.3
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• pp.187-210
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• 2011

This study aims at examining how academic library staffs' service quality affects the user satisfaction and continuance intention, and also seeking practical solutions for improving the satisfaction and continuance intention in academic libraries. Despite the value and importance of human-mediated library services which enable various library services to be more valuable, relatively few prior studies focuses on this topic. This study develops a conceptual framework based on the concepts of service quality, satisfaction, and continuance intention. This framework provides a useful guideline for data collection and data analyses. Values of this study include ensuring the continuance intention by suggesting strategies that may increase users' positive attitude toward human-mediated services in academic libraries, and methodologically, using both quantitative and qualitative methods.