• Journal of Chest Surgery
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• v.32 no.7
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• pp.603-612
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• 1999

Background : It has been documented that brief repetitive periods of ischemia and reperfusion (ischemic preconditioning, IP) enhances the recovery of post-ischemic contractile function and reduces infarct size after a longer period of ischemia. Many mechanisms have been proposed to explain this process. Recent studies have suggested that transient increase in the intracellular calcium may have triggered the activation of protein kinase C(PKC); however, there are still many controversies. Accordingly, the author performed the present study to test the hypothesis that preconditioning with high concentration of calcium before sustained subsequent ischemia(calcium preconditioning) mimics IP by PKC activation. Material and Method : The isolated hearts from the New Zealand White rabbits(1.5∼2.0 kg body weight) Method: The isolated hearts from the New Zealand White rabbits(1.5∼2.0 kg body weight) were perfused with Tyrode solution by Langendorff technique. After stabilization of baseline hemodynamics, the hearts were subjected to 45-minute global ischemia followed by a 120-minute reperfusion with IP(IP group, n=13) or without IP(ischemic control, n=10). IP was induced by single episode of 5-minute global ischemia and 10-minute reperfusion. In the Ca2+ preconditioned group, perfusate containing 10(n=10) or 20 mM(n=11) CaCl2 was perfused for 10 minutes after 5-minute ischemia followed by a 45-minute global ischemia and a 120-minute reperfusion. Baseline PKC was measured after 50-minute perfusion without any treatment(n=5). Left ventricular function including developed pressure(LVDP), dP/dt, heart rate, left ventricular end-diastolic pressure(LVEDP) and coronary flow(CF) was measured. Myo car ial cytosolic and membrane PKC activities were measured by 32P-${\gamma}$-ATP incorporation into PKC-specific pepetide. The infarct size was determined using the TTC (tetrazolium salt) staining and planimetry. Data were analyzed using one-way analysis of variance(ANOVA) variance(ANOVA) and Tukey's post-hoc test. Result: IP increased the functional recovery including LVDP, dP/dt and CF(p<0.05) and lowered the ascending range of LVEDP(p<0.05); it also reduced the infarct size from 38% to 20%(p<0.05). In both of the Ca2+ preconditioned group, functional recovery was not significantly different in comparison with the ischemic control, however, the infarct size was reduced to 19∼23%(p<0.05). In comparison with the baseline(7.31 0.31 nmol/g tissue), the activities of the cytosolic PKC tended to decrease in both the IP and Ca2+ preconditioned groups, particularly in the 10 mM Ca2+ preconditioned group(4.19 0.39 nmol/g tissue, p<0.01); the activity of membrane PKC was significantly increased in both IP and 10 mM Ca2+ preconditioned group (p<0.05; 1.84 0.21, 4.00 0.14, and 4.02 0.70 nmol/g tissue in the baseline, IP, and 10 mM Ca2+ preconditioned group, respectively). However, the activity of both PKC fractions were not significantly different between the baseline and the ischemic control. Conclusion: These results indicate that in isolated Langendorff-perfused rabbit heart model, calcium preconditioning with high concentration of calcium does not improve post-ischemic functional recovery. However, it does have an effect of limiting(reducing) the infart size by ischemic preconditioning, and this cardioprotective effect, at least in part, may have resulted from the activation of PKC by calcium which acts as a messenger(or trigger) to activate membrane PKC.

• Korean Journal of Cognitive Science
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• v.28 no.2
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• pp.111-131
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• 2017

The connectionist model is one approach to studying language processing from a computational perspective. And building a representation in the connectionist model study is just as important as making the structure of the model in that it determines the level of learning and performance of the model. The connectionist model has been constructed in two different ways: localist representation and distributed representation. However, the localist representation used in the previous studies had limitations in that the unit of the output layer having a rare target activation value is inactivated, and the past distributed representation has the limitation of difficulty in confirming the result by the opacity of the displayed information. This has been a limitation of the overall connection model study. In this paper, we present a new method to induce distributed representation with local representation using abstraction of information, which is a feature of restricted Boltzmann machine, with respect to the limitation of such representation of the past. As a result, our proposed method effectively solves the problem of conventional representation by using the method of information compression and inverse transformation of distributed representation into local representation.

• Journal of Sensor Science and Technology
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• v.12 no.1
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• pp.16-23
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• 2003

Thermoluminescent properties of $Li_2B_4O_7$ single crystal grown by Czochralski method have been investigated. The high quality $Li_2B_4O_7$ single crystal without core was obtained at rotation speed of 10 rpm for seed crystal and pulling speed below $0.18\;mm{\cdot}h^{-1}$. The structure of $Li_2B_4O_7$ single crystal was classified as tetragonal by XRD analysis. The TL glow curve was composed with three overlapped peaks which can be easily deconvoluted and the TL response of $Li_2B_4O_7$ single crystal TLD to X-ray radiation is linear within the range of $50\;mGy{\sim}1.5\;Gy$. Activation energies of three TL glow peaks analyzed by the various heating rates method and PL spectrum were 0.93, 1.78 and 2.25 eV, respectively.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.165-171
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• 1998

The $Y_1Ba_2Cu_3O_{7-x}$(123) superconductor powders were prepared by pyrophoric synthesis method(PSM) using $Y_2O_3$(99.9%), $BaCO_3$(99.9%), and CuO(99.9%) powders. The phase formation and reaction kinetics of 123 superconductor manufactured with powders prepared in various pHs of pyrophoric synthetic solution have been studied through the experiments at various heat treatment temperatures and times. Inductively coupled plasma(ICP) spectroscopy and scanning electron microscopy(SEM) measurements were performed to examine the composition and morphology of the sample. X-ray diffraction(XRD) analysis was done to determine phase formation and conversion ratio of Y-Ba-Cu-O systems. The 123 powder prepared at pH 7(${\pm}0.3$) yields the best result in terms of purity, homogeneity, and reactivity. The activation energies(${\Delta}E_a$) of 123 phase formation were found to be 191 kJ/mol and 230kJ/mol in solid state reaction method and pyrophoric synthesis method, respectively.

• Journal of Chest Surgery
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• v.31 no.12
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• pp.1200-1205
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• 1998

Background: Lung cancer formation is a multistage process involving activation of protooncogene and inactivation of tumor suppressor genes. We evaluate the significance of cyclin D1, p53, bcl-2 gene mutations in patients with curatively resected stage IIIA non-small cell lung cancer(NSCLC). Material and Method: One hundred consecutive cases of stage IIIA lung cancers from patients operated on curatvely between 1990 and 1995 for which adequate paraffin blocks and clinical history were available. Immunohistochemical studies were performed on the representative tissue sections from each case by the labelled streptovidin- biotin method. Sections for cyclin D1, p53, Bcl-2 immunostaining were pretreated in a microwave oven for 10 to 20 minutes in citrate buffer before immunostaining. The overnight incubation with NCL-cyclin D1-GM for cyclin D1, with clone DO-7 for p53, with clone 124 for bcl-2 was done. Mean follow-up was 24.1 months (range 2-84 months) after operation. Result: One hundred cases of lung cancers were composed of 56 cases of squamous cell carcinoma, 37 cases of adenocarcinoma, 5 cases of adenosquamous cell carcinoma, and 2 cases of large cell carcinoma. The 5-year survival was 32.1%. The positive expression rate of cyclin D1 was 35%, p53 was 56%, and bcl-2 was 17%. But there were no correlation between cyclin D1, p53, Bcl-2 protein expression and survival. Conclusion: These observation indicate that cyclin D1, p53, bcl-2 protein overexpression might be implicated in the oncogenesis of non-small cell lung carcinomas but they have no usefulness as a prognostic marker.

• Journal of the Mineralogical Society of Korea
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• v.22 no.1
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• pp.63-72
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• 2009

Carbon-coated lithium iron phosphate ($LiFePO_4/C$) composites are synthesized by the modified mechanical activation method (modified MA process) and studied by the Rietveld structural refinement. Rietveld indices of $LiFePO_4/C$ indicate good fitting with $R_p=8.14%,\;R_{wp}=11.1%,\;R_{exp}=9.09%,\;R_B=3.88%$, and S (GofF, Goodness of fit) = 1.2, respectively. $LiFePO_4/C$ with a space group Pnma shows a = 10.3229(3)${\AA}$, b = 6.0052(2) ${\AA}$, c = 4.6939(1) ${\AA}$, and V = 290.98(1) ${\AA}^3$ in dimension, indicating good agreements with those of previous works. Synthetic powders are nano-sized ($65{\sim}90nm$) homogeneous particles with high purity. Thus the modified MA method will be an efficient process to get a high quality cathode material for commercial lithium batteries.

• Journal of the Korea Concrete Institute
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• v.21 no.6
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• pp.713-718
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• 2009

Advanced industries-IT, BT, NT and ET are rapidly developing in 21 century. And the cement industry is becoming the principal factor in air pollution because of the creation of $CO_2$ during manufacturing. Also, the cement industry will be faced with a crisis due to the exhaustion of natural resources. In this study, nano cement by Bottom-up method of a chemical synthesis was developed. The generation of $CO_2$ during the plasticization process of cement manufacturing was avoided. The purpose was to produce building materials that have both high strength and durability as the high value-added growth engine industry of the 21 century. The nano cement was developed using hydrothermal synthesis. This is a method of mixing after ripening, by manufacturing the high density gel and low gel, which does not require special test equipment or pressure conditions to produce. Particle size, SEM, EDX, and porosity tests were conducted. This study investigated the compressive strength of concrete with various compositions. Specimens were tested for compressive strength at 3, 7, 14 and 28 days. The medium-sized (50% by weight) cement particles created by chemical synthesis were less than 168 nm. The compressive strength of the mortar prepared using this cement was 53.9 MPa. But it was judged that succeeding study will be necessary for development of nano building materials with high ability and economical analysis.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.8
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• pp.123-144
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• 1997

This study, by setting the systems of room sale promotion, analyzing the actual status and the present working state with its center on the 'RHotel' that is a special grade-two hotel and the sales promotion activities of each type, intends to understand the presentstatus of the hotel and present its problems and the method for improvement. The strategy of salespromotion and the ineffectivenessof the system organization were found to be imminent in the sales promotion activities as its problems, and the importanceis being not attached to the actual substance rather than to the actualresults, such as the advertisement and publicity strategies, the irrationality of sales personnel controland its evaluation method, and therefore, the goal-oriented control is not being takenad its problems are emerging. Therefore, as an improvement plan, we ought to put the plan of the hotel merchandising into action for customers to buy what they want, the establishment of the customer-oriented sales promotionservice and the communication channel using the brand-new managerial skills, systemaizesales promotion method sand strategies, develop the organizational and systematic strategies develop the organizatinal and systemactic strategies and goods for the sake of the image-making and room sales promotion of hotels, develop the activation ways of flexible operation, and also need to develop the skills of sales promotion. Accordingly, by doing irrationalsales activities in the system and the promotion with its center on the sales promotion department, and it sis urgently required that we streng then the comodity developments fitting the hotel's traits, such as uniformpolicy of cost, mass-communicationactivities for sales promotion, the improvement of non-effectiveness, and advertisement of hotel items, and the publishing of public relation books. Therefore, the best weapon for hotels before other purchaseis to be discriminatized from other competitive hotel with theunderstanding of the psychology and activities of customers, and the communicatin with customers, and to set up organicprograms of sales promotionstrategies. Also we must promote our sales in accordance with the desire of new customers, gater the market information of customers, all the time, and systematize the facility improvement, managerial policy, business strategiescorresponding with the desire of customers. By doing so, we are able to seek, at the same time, both the satis faction of customers and the sales maximization of the hotels that will perfrom the activities of sales promotion and management.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.230-237
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• 2017

In this study, electrochemical methods were used to determine the optimum protection potential of S355ML steel for the cathodic protection of offshore wind-turbine-tower substructures. The results of potentiodynamic polarization experiments indicated that the anodic polarization curve did not represent a passivation behavior, while under the cathodic polarization concentration, polarization was observed due to the reduction of dissolved oxygen, followed by activation polarization by hydrogen evolution as the potential shifted towards the active direction. The concentration polarization region was found to be located between approximately -0.72 V and -1.0 V, and this potential range is considered to be the potential range for cathodic protection using the impressed current cathodic protection method. The results of the potentiostatic experiments at various potentials revealed that varying current density tended to become stable with time. Surface characterization after the potentiostatic experiment for 1200 s, by using a scanning electron microscope and a 3D analysis microscope confirmed that corrosion damage occurred as a result of anodic dissolution under an anodic polarization potential range of 0 to -0.50 V, which corresponds to anodic polarization. Under potentials corresponding to cathodic polarization, however, a relatively intact surface was observed with the formation of calcareous deposits. As a result, the potential range between -0.8 V and -1.0 V, which corresponds to the concentration polarization region, was determined to be the optimum potential region for impressed current cathodic protection of S355ML steel.

• Korean Journal of Construction Engineering and Management
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• v.14 no.5
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• pp.164-174
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• 2013

It has been seriously difficult to create demand of modular construction because Korean modular method has been considered as container house or lightweight steel house. Actually, barrier factor of modular construction for activation was difficult to produce modular continuously in factories based on stable amount of demands. So, this research found successive factors of modular construction and proposed the method of demand creation through a plethora of case analysis by building types. In addition, this research found the scale of modular potential market. Owners will be able to use this strategy that is proposed in this research when they make a decision about construction system. Also, the modular construction can make potential market in Korea. As a result, modular system producer can make their business strategies and make continuous demand by conjugating the method of creating demand for modular construction which is proposed in this research.