• Korean Journal of Microbiology
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• v.32 no.3
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• pp.222-231
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• 1994

Kinetic analysis was done to elucidate the reaction mechanism of purine nucleoside phosphorylase (PNP) in Saccharomyces cerevisiae. The binary complexes of PNP${\cdot}$phosphate and PNP${\cdot}$ribose 1-phosphate were involved in the reaction mechanism. The initial velocity and product inhibition studies demonstrated were consistent with the predominant mechanism of the reaction being an ordered bi, bi reaction. The phosphate bound to the enzyme first, followed by nucleoside and base were the first product to leave, followed by ribose 1-phosphate. The kinetically suggested mechanism of PNP in S. cerevisiae was in agreement with the results of protection studies against the inactivation of the enzyme by sulfhydryl reagents, p-chloromercuribenzoate (PCMB) and 5,5'-dithiobisnitrobenzoate (DTNB). PNP was protected by ribose 1-phosphate and phosphate, but not by nucleoside or base, supporting the reaction order of ordered bi, bi mechanism. PCMB or DTNB-inactivated PNP was totally reactivated by dithiothreitol (DTT) and the activity was returned to the level of 77% by 2-mercaptoethanol, indicating that inactivation was reversible. The kinetic behavior of the PCMB-inactivated enzyme had been changed with higher $K_m$ value of inosine and lower $V_m$, and was restored by DTT. Inactivation of enzyme by DTNB showed similar pattern of K sub(m) value with that by PCMB, but had not changed the $V_m$ value, significantly. Negative cooperativity was not found with PCMB or DTNB treated PNP at high concentration of phosphate.

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.60-67
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• 2001

Multicast Protocol for multimedia service on the Internet can be classified into two types, e.g., source based tree and shared tree according to difference of tree construction method. Shared tree based multicast is known to show outstanding results in the aspect of scalability than source based tree. Generally, There have been lots of researches on the method to satisfy QoS constraints through proper Rendezvous Point (RP) in the shared tree. In addition, as the multicast group members join and leave dynamically in the service time, RP of the shared tree should b be reselected for guranteeing Qos to new member, But, RP reselection method has not been considered generally as the solution to satisfy QoS C constraints. In this paper, new initial RP selection and RP reselection method are proposed, which utilize RTCP (Real Time Control Protocol) report packet fields. Proposed initial RP selection and RP reselection method use RTCP protocol which underlying multimedia application service So, the proposed method does not need any special process for collecting network information to calculate RP. New initial RP selection method s shows better performance than random and topology based one by 40-50% in simulation. Also, RP reselection method improves delay p performance by 50% after initial RP selection according to the member’s dynamicity.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.1-18
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• 1996

There are many advantages when using IIF and DNA probe methods over anaerobic culture method in that they are time-and effort-saving, more precise and more sensitive. Furthermore, in IIF and DNA probe methods, the detection is possible only with small amount of bacteria, the quantitative analysis is possible, and the cell viability is not necessary. The purpose of this study is to observe the incidence of P.endodontalis by carrying out anaerobic culture, IIF and colony lift using DNA probe method respectively, and to compare these 3 methods in terms of effectiveness and sensitivity in order to identify the most effective detection method. 30 teeth with at least one clinical symptoms, with single canal, and with pulp necrosis were sampled. For sampling bacteria, access cavity was prepared after disinfecting tooth and its surroundings. Then the paper point was inserted up to the periapical area, leave there for a while, and finally it was placed into PRAS Ringer's sol. and PBS sol. In anaerobic culture method, P.endodontalis was identified by biochemical tests after subculturing black and brown colonies which were produced after 7 days of incubation on BAP and Brucella BAP in anaerobic chamber. To identify P.endodontalis in IIF method, species-specific polyclonal rabbit-antisera of P.endodontalis(ATCC 35406) was reacted with sampled PBS sol. dispensed onto glass slide, and then P.endodontalis was examined by phase contrast microscopy after incubating with Goat anti-rabbit lgG conjugated to Fluorescein isothiocyanate. For colony lift using DNA probe method, membranes were laid over colonies on the surface of BAP and were hybridized with cloned DNA probe of P.endodontalis. The existence of P.endodontalis was then identified by the methods of chemiluminescent detection and color metric detection. Black colony was found in 11 teeth out of 30 teeth and P.endodontalis was detected in 6 teeth (20 %) by anaerobic culture method, 16 teeth (53 %) by IIF method, and 7 teeth (23 %) by DNA probe method. IIF method is significantly better in detecting P.endodontalis than DNA probe method and anaerobic culture method. There was no significant differences between DNA probe method and anaerobic culture method. There was significant correlation between the formation of black colony and the existence of P.endodontalis. The probability of detecting P.endodontalis when black colony being present is 2.89 times higher than when not being present. There was significant relationship between the foul odor of clinical symptoms and P.endodontalis. The sensitivity of existing P.endodontalis when foul odor being present was 93.75 %, while the specificity of not existing P.endodontalis when foul odor not being present was 28.57 %. These results suggested that the probes of P.endodontalis will be used to decide the method and prognosis in endodontic treatments.

• Journal of the Korean earth science society
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• v.40 no.6
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• pp.599-605
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• 2019

Rice yield (kg 10a^-1) in South Korea was estimated by meteorological variables that are influential factors in crop growth. This study investigated the possibility of anticipating the rice yield variability using a simple but an efficient statistical method, a multiple linear regression analysis, on the basis of the annual variation of meteorological variables. Due to heterogeneous environmental conditions by region, the yearly rice yield was assessed and validated for each province in South Korea. The monthly mean meteorological data for the period 1986-2018 (33 years) from 61 weather stations provided by Korean Meteorological Administration was used as the independent variable in the regression analysis. An 11-fold (leave-three-out) cross-validation was performed to check the accuracy of this method estimating rice yield at each province. This result demonstrated that temporal variation of rice yield by province in South Korea can be properly estimated using such concise procedure in terms of correlation coefficient (0.7, not significant). Furthermore, the estimated rice yield well captured spatial features of observation with mean bias of 0.7 kg 10a^-1 (0.15%). This method may offer useful information on rice yield by province in advance as long as accurate agro-meteorological forecasts are timely obtained from climate models.

• Journal of Korean Neurosurgical Society
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• v.29 no.7
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• pp.910-917
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• 2000

Introduction : The management of chordomas and chondrosarcomas in the skull base is difficult due to the critical location, locally aggressive nature, and high recurrence rate. The authors present the effectiveness of surgical removal and radiation therapy on survival and tumor recurrence. Material and Methods : Thirty cranial base chordomas and chondrosarcomas from 23 patients(14 patients with chordomas and 9 patients with chondrosarcomas) were operated in our institution between 1985 and 1998. There were 15 men and 8 women, with a mean age of 40.7 years. The largest diameter of tumors ranged from 15 to 70mm (mean 41.5). The extent of surgical removal was subtotal or total in a half(15 operations). In nineteen operations, tumors were removed by conventional approaches and skull base approaches were applied in 11 operations. Postoperative radiation therapy was performed in 16(70%) patients. The mean duration of follow up is 50 months(1- 156 months). Results : The 3- and 5-year survival rates(YSR) of overall patient are 75% and 67%, respectively. The analysis showed that 1) skull base approach to chordomas and chondrosarcomas showed a tendency to remove more portion of the tumors(p＝0.058) but leave more frequent incidence of new deficits(p＝0.047) : 2) larger tumor diameter af-fected the extent of removal(p＝0.028) : 3) the extent of removal seemed to be the determining factor for overall survival and recurrence-free survival(the 5-YSR and RFSR of subtotal or total removal group are 92% and 80% vs. 40% of partial removal or biopsy group) : 4) conventional radiation therapy improved patient survival(5-YSR of patients who received RT is 76% whereas 5-YSR of those who didn't receive RT is 43%) but failed to prolong long-term recurrence-free survival. Conclusion : The extent of removal and postoperative radiation therapy are determining factors of patients' survival in skull base chordomas and chondrosarcomas. However, none of these factors significantly influenced the survival in multivariate analysis. Aggressive surgical removal of more than subtotal resection combined with postoperative radiation therapy seems to be the choice of therapy in the management of these tumors.

• Journal of the Korean Institute of Landscape Architecture
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• v.46 no.3
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• pp.79-91
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• 2018

This study proposes the difference of awareness and improvement plan of building-related landscape systems through a cognition survey of building owners, public officials, and experts. The main results are as follows. First, all three groups are highly aware of the need to secure urban green spaces. Even if private property rights are restricted, the level of awareness that green space should be secured for public benefit is high. The level of interest in the building-related landscape system was also surveyed to a greater degree. Second, the survey respondents, including the building owner group, answered that there is a need to strengthen the building-related landscape area standards. It can be seen that there is a need to revise the relaxation of the building-related landscape area standards through an amendment of the Building Ordinance in many local governments. Third, most municipalities are not equipped with an organizational system that can promote the work of building-related landscape. It is necessary to newly hire civil servants for landscape design, maintenance, and management specialization, or to expand co-working relationships with related departments. Fourth, building owners are interested in building-related landscape, but they do not know specific management methods and leave the landscape space. The municipality needs to offer guidance on landscape architectural design and construction methods that the building owners can easily follow and to support the voluntary landscape space management on the part of the local residents by supporting the trees. Fifth, in order to improve the building-related landscape system, it is necessary to verify the effect of the building-related landscape and spread a consensus. At the government level, in order to enable building owners to recognize the value of the landscape space in connection with an urban regeneration project, it is necessary to present an example of an excellent building-related landscape installation via a pilot project.

• Journal of KIISE:Databases
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• v.33 no.7
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• pp.655-667
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• 2006

Due to the rapid development in mobile communication technologies, the usage of mobile devices such as cellular phones and PDAs becomes increasingly popular. One of the best ways to maximize the usability of mobile devices is to make them aware of their current locations and the locations of other fixed and mobile objects. In this paper, we propose a cost-effective Bus Information System, ACE-BIS, which utilizes a mobile device to retrieve the bus routes to reach a destination from the current location. To accomplish this task, ACE-BIS maintains a small amount of information on bus stops and bus routes in a mobile device and runs a heuristic routing algorithm based on such information. When a user asks more accurate route information or calls for a 'leave later query', ACE-BIS entrusts the task to a server into which real-time traffic and bus location information is being collected. By separating the roles into a mobile device and a server, ACE-BIS is able to provide bus routes at the lowest cost for wireless communications, without imposing much burden to a server. The results of extensive experiments revealed that ACE-BIS is effective and scalable in most experimental settings.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.68-78
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• 2010

As the IP multicast function is very slowly deployed in Internet due to its scalability problem and inter-domain interoperability problem, interest in the P2P(Peer-to-Peer) streaming technologies for the realtime multimedia multicast applications such as IPTV is highly growing. This paper proposes a P2P streaming method for the QoS-sensitive multimedia multicast applications such as highly-interactive personal IPTV and video conferences. The proposed P2P streaming method allows an application to construct a reliable streaming tree in which a proper number of backup peers are placed according to its reliability requirement. The reliable streaming tree reduces the reconnection delay, occurred in the case of a normal and/or abnormal peer leave, so as to minimize the loss of streaming data. In the proposed P2P streaming method, the join delay of a peer called startup delay is also substantially reduced because the bandwidth and end-to-end delay information of every peer kept in a distributed way allows the target peer for a joining peer to be able to be quickly determined. Moreover, the proposed method's peer admission control mechanism based on the bandwidth and end-to-end delay enables the delay-bounded streaming services to be provided for its corresponding applications.

• Toxicological Research
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• v.22 no.3
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• pp.283-291
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• 2006

The survival and growth of epithelial cells depends on adhesion to the extracellular matrix. An adhesion signal may regulate the initiation of differentiation, since epidermal keratinocytes differentiate as they leave the basement membrane. A metabolically dead cornified cell envelope is the end point of epidermal differentiation so that this process may be viewed as a specialized form of programmed cell death. In order to investigate the precise cellular signaling events loading to terminal differentiation of keratinocytes, we have utilized HaCaT cells to monitor the biological consequences of $Ca^{2+}$ stimulation and numerous downstream signaling pathways, including activation of the extracellular signal-regulated protein kinase(ERK) pathway and activation of phosphatidylinositol 3-kinase(PI3K). The results presented in this study show that $Ca^{2+}$ function as potent agents for the differentiation of HaCaT keratinocytes, and this differentiation depends or the activation of ERK, Protein kinase B(PKB) and p70 ribosomal protein S6 kinase(p70S6K). Finally, the results show that the expression of Activator protein 1(AP-1; c-Jun and c-Fos) increased following $Ca^{2+}$-mediated differentiation of HaCaT cells, suggesting that ERK-mediated AP-1 expression is critical for initiating the terminal differentiation of keratinocytes.

• Archives of Plastic Surgery
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• v.33 no.6
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• pp.784-788
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• 2006

Purpose: For the reconstruction of the ankle joint as well as the soft tissue defect in the distal lower leg, a free flap or a local flap has been used, and because of the condition of patients, if a complex microvascular surgery under general anesthesia could not be performed, it could be reconstructed by using the distally based lateral supramalleolar fascio-cutaneous island flap using the perforating branch of the peroneal artery in the ankle area. Methods: The study subjects were 4 male patients between 53 years and 73 years of age. 2 cases were tissue defect in the medial malleolus area due to systemic diseases such as gouty arthritis accompanied traffic accident, diabetes mellitus foot, atherosclerotic obliterans, etc., 1 case was the defect in the pretibia area, and 1 case was the defect underneath the lateral malleolus, which was reconstructed by the distally based lateral supramalleolar fascio-cutaneous island flap. The donor area was the skin harvested from the groin, and the full thickness skin graft was performed. The size of the flap varied from $4{\times}3cm$ to $9{\times}6cm$. As the flap border, the medial side was to the tibialis anterior tendon, the lateral side was to the fibula crest, and the proximal area was less than the fibula size. Results: The consequence is that, in total 4 cases, the congestion in the flap began from 12 hours after the surgery, and the progression of congestion was ceased on the 5th day after the surgery, and finally epidermal bulla and sloughing, partial necrosis was developed. After the end of necrosis, the defect area was reconstructed successfully by the second full thickness skin graft. Conclusions: Although the distally based lateral supramalleolar fascio-cutaneous island flap has the shortcoming of requiring the second skin graft, it has the advantages that it does not require a long complex microsurgery, the flap itself is thin, it is similar to the color of the skin in the recipient area, and it does not leave a big scar in the donor area. Therefore, it is thought that for the cases who could not undergo a long complex surgery due to systemic diseases or the cases of patients whose condition of the recipient area is not suitable for microsurgery, the lateral supramalleolar fascio-cutaneous island flap is very useful for the reconstruction of the distal lower leg and the ankle joint area.