• The KIPS Transactions:PartC
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• v.14C no.1 s.111
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• pp.55-64
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• 2007

Behind the popularity of VoIP in these days, it may present significant security challenges in privacy and accounting. Authentication and message encryption are considered to be essential mechanisms in VoIP to be comparable to PSTN. SIP is responsible for setting up a secure call in VoIP. SIP employs TLS, DTLS or IPSec combined with TCP, UDP or SCTP as a security protocol in VoIP. These security mechanisms may introduce additional overheads into the SIP performance. However, this overhead has not been understood in detail by the community. In this paper we present the effect of the security protocol on the performance of SIP by comparing the call setup delays among security protocols. We implement a simulation of the various combinations of three security protocols and three transport layer protocols suggested for SIP. UDP with any combination of security protocols performs a lot better than the combination of TCP. TLS over SCTP may impose higher impact on the performance in average because TLS might have to open secure channels as the same number of streams in SCTP. The reasons for differences in the SIP performances are given.

• Restorative Dentistry and Endodontics
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• v.14 no.1
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• pp.57-70
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• 1989

The purpose of this study was to investigate the effect of salivary gland on the calcification of dentin in rats. 80 Sprague-Dawley male rats that weighed approximately 120gm were used in this study. 5 rats among them were shared as controls. 75 rats received sialoadenectomy were divided into submaxillary adenectomy group, parotidectomy group, and submaxillary-parotid gland combined removal group. In experimental groups, 25 rats in each of the 3 groups were sacrificed at the following intervals; 3 days, 1, 2, 3 and 4 weeks. All animals were sacrificed by vascular perfusion with 10% formalin. The maxillary incisors including periapical tissues were removed and defatted in 20% KOH solution at $0^{\circ}C$ for 24 hours, and dehydrated with acetone. Each tooth specimen was attached on the stab for scanning electron microscopic study. Gold was coated on the each specimen in the thickness of 300${\AA}$ at D.C. 1400V, 6mA for 6 minutes with coating machine (Eiko IB-3). Inner dentinal surfaces of the specimens were observed with SEM (Hitachi S-450). The results were as follows, 1. Parotidectomy groups were found to be inhibited the formation of dentinal calcification compared to submaxillary adenectomy groups in the eady stages. 2. Combined removal of submaxillary and parotid gland was appeared to cause more severe inhibition effect on the dentinal calcification than that of each salivary gland separately. 3. Inhibition of the calcification and mineralization of dentin caused by sialoadenectomy was more extreme from 3 day to 2 weeks after beginning of the experiments. However it was tended to be normalized after that. 4. Salivary gland was responsible for alterations in calcification and mineralization of dentinal growth.

• Restorative Dentistry and Endodontics
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• v.29 no.4
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• pp.399-408
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• 2004

Odontoblasts are responsible for the formation and maintenance of dentin. They are known to synthesize unique gene products including dentin sialophosphoprotein (DSPP). Another unique genes of the cells remain unclear. OD314 was isolated from the odontoblasts/pulp cells of rats and partially characterized as an odontoblast-enriched gene (Dey et al., 2001). This study aimed to elucidate the biological function of OD314, relating to odontoblast differentiation and dentinogenesis. After determining the open reading frame (ORP) of OD314 by transient transfection analysis using green fluorescent protein (GPP) expression vector, mRNA in-situ hybridization, immunohistochemistry, reverse transcription-polymerase chain reaction (RT-PCR) and western analysis were performed. The results were as follows: 1. In in-situ hybridization, OD314 mRNAs were expressed in odontoblasts of developing coronal and root pulp. 2. OD314 was a novel protein encoding 154 amino acids, and the protein was mainly expressed in cytoplasm by transient transfection analysis. 3. Mineralized nodules were associated with multilayer cell nodules in the culture of human dental pulp cells and first detected from day 21 using alizarin-red S staining. 4. In RT-PCR analysis, OD314, osteocalcin (OC) and DSPP strongly expressed throughout 28 days of culture. Whereas, osteonectin (ON) mRNA expression stayed low up to day 14, and then gradually decreased from day 21. 5. Western blots showed an approximately 17 kDa band. OD314 protein was expressed from the start of culture and then increased greatly from day 21. In conclusion, OD314 is considered as an odontoblast-enriched gene and may play important roles in odontoblast differentiation and dentin mineralization.

• Journal of Microbiology and Biotechnology
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• v.23 no.6
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• pp.864-871
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• 2013

The recombinant strain P. pastoris GS115-lccC was used to produce laccase with high activity. Factors influencing laccase expression, such as pH, methanol concentration, copper concentration, peptone concentration, shaker rotate speed, and medium volume were investigated. Under the optimal conditions, laccase activity reached 12,344 U/L on day 15. The recombinant enzyme was purified by precipitating and dialyzing to electrophoretic homogeneity, and was estimated to have a molecular mass of about 58 kDa. When guaiacol was the substrate, the laccase showed the highest activity at pH 5.0 and was stable when the pH was 4.5~6.0. The optimal temperature for the laccase to oxidize guaiacol was $60^{\circ}C$, but it was not stable at high temperature. The enzyme could remain stable at $30^{\circ}C$ for 5 days. The recombinant laccase was used to degrade chlorpyrifos in several laccase/mediator systems. Among three synthetic mediators (ABTS, HBT, VA) and three natural mediators (vanillin, 2,6-DMP, and guaiacol), vanillin showed the most enhancement on degradation of chlorpyrifos. Both laccase and vanillin were responsible for the degradation of chlorpyrifos. A higher dosage of vanillin may promote a higher level of degradation of chlorpyrifos, and the 2-step addition of vanillin led to 98% chlorpyrifos degradation. The degradation of chlorpyrifos was faster in the L/V system ($k_{obs}$ = 0.151) than that in the buffer solution ($k_{obs}$ = 0.028).

• Clinical and Experimental Pediatrics
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• v.54 no.1
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• pp.11-16
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• 2011

Purpose: Enterovirus 71, one of the enteroviruses that are responsible for both hand-foot-and-mouth disease and herpangina, can cause neural injury. During periods of endemic spread of hand-foot-andmouth disease caused by enterovirus 71, CNS infections are also frequently diagnosed and may lead to increased complications from neural injury, as well as death. We present the results of our epidemiologic research on the clinical manifestations of children with CNS infections caused by enterovirus 71. Methods: The study group consisted of 42 patients admitted for CNS infection by enterovirus 71 between April 2009 and October 2009 at the Department of Pediatrics of 5 major hospitals affiliated with the Catholic University of Korea. We retrospectively reviewed initial symptoms and laboratory findings on admission, the specimen from which enterovirus 71 was isolated, fever duration, admission period, treatment and progress, and complications. We compared aseptic meningitis patients with encephalitis patients. Results: Of the 42 patients (23 men, 19 women), hand-foot-and-mouth disease was most prevalent (n=39), followed by herpangina (n=3), upon initial clinical diagnosis. Among the 42 patients, 15 (35.7%) were classified as severe, while 27 (64.3%) were classified as mild. Factors such as age, fever duration, presence of seizure, and use of intravenous immunoglobulin (IVIG) were statistically different between the 2 groups. Conclusion: Our results indicate that patients with severe infection caused by enterovirus 71 tended to be less than 3 years old, presented with at least 3 days of fever as well as seizure activity, and received IVIG treatment.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.3
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• pp.241-249
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• 1997

The aim of the present study is to examine the brainstem sites where the electrical stimulation produces a suppression of dorsal horn neuron responses of neuropathic rats. An experimental neuropathy was induced by a unilateral ligation of L5-L6 spinal nerves of rats. Ten to 15 days after surgery, the spinal cord was exposed and single-unit recording was made on wide dynamic range (WDR) neurons in the dorsal horn. Neuronal responses to mechanical stimuli applied to somatic receptive fields were examined to see if they were modulated by electrical stimulation of various brainstem sites. Electrical stimulation of periaqueductal gray (PAG), n. raphe magnus (RMg) or n. reticularis gigantocellularis (Gi) significantly suppressed responses of WDR neurons -to both noxious and non-noxious stimuli. Electrical stimulation of other brainstem areas, such as locus coeruleus. (LC) and n. reticularis paragigantocellularis lateralis (LPGi), produced little or no suppression. Microinjection of morphine into PAG, RMg, or Gi also produced a suppression as similar pattern to the case of electrical stimulation, whereas morphine injection into LC or LPGi exerted no effects. The results suggest that PAG, NRM and Gi are the principle brainstem nuclei involved in the descending inhibitory systems responsible for the control of neuropathic pain. These systems are likely activated by endogenous opioids and exert their inhibitory effect by acting on WDR neurons in the spinal cord.

• Toxicological Research
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• v.34 no.3
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• pp.241-247
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• 2018

Lactobacillus (LAB) have been reported to exert both harmful and beneficial effects on human and animal health. Recently, it has been reported that dysbiosis and bacterial translocation contribute to liver fibrosis. However, the role of Gram-positive LAB in the situation of chronic liver diseases has not been yet elucidated. Liver injury was induced by bile duct ligation (BDL) in LAB or control-administered mice. Liver fibrosis was enhanced in LAB-administered mice compared with control-treated mice as demonstrated by quantification of Sirius-red positive area, hydroxyproline contents and fibrosis-related genes ($Col1{\alpha}1$, Acta2, Timp1, Tgfb1). Moreover, LAB-administered mice were more susceptible to BDL-induced liver injury as shown by increased ALT and AST level of LAB group compared with control group at 5 days post BDL. Consistent with serum level, inflammatory cytokines ($TNF-{\alpha}$, IL-6 and $IL-1{\beta}$) were also significantly increased in LAB-treated mice. Of note, LAB-treated liver showed increased lipoteichoic acid (LTA) expression compared with control-treated liver, indicating that LAB-derived LTA may translocate from intestine to liver via portal vein. Indeed, responsible receptor or inflammatory factor (PAFR and iNOS) for LTA were upregulated in LAB-administered group. The present findings demonstrate that administration of LAB increases LTA translocation to liver and induces profibrogenic inflammatory milieu, leading to aggravation of liver fibrosis. The current study provides new cautious information of LAB for liver fibrosis patients to prevent the detrimental effect of LAB supplements.

• Plant Biotechnology Reports
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• v.5 no.3
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• pp.273-281
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• 2011

Diverse epigenetic phenotypes are frequently found during research on transgenic plants. To understand the factors underlying such diversity, hundreds of independent 35S-GFP transgenic N. benthamiana plants were analyzed. The diverse GFP-expression phenotypes of the transgenic plants were classified into three major types based on the GFP expression patterns and their response to 35S-GFP agroinfiltration: steady-green, silenced and non-uniform phenotype. The non-uniform phenotype was further sub-divided into five minor phenotypes: variegated, red-dropped, on-silencing, partitioned and misty, according to the distribution of GFP expression on the leaves. Many of transgenic plants continuously generated diverse phenotypes over several generations despite the transgene identity. Such epigenetic GFP phenotyping was found to be the result of spontaneous transgene silencing mediated by either or both of post-transcriptional gene silencing (PTGS) and transcriptional gene silencing (TGS). This finding was verified by the detection of 21- and 24-nt small interfering RNA (siRNA) molecules, and DNA methylation in the transgenic plants that showed repeated epigenetic variation. Agroinfiltration demonstrated that irregular distribution of GFP on a leaf was the result of erratic transgene silencing, and the technique also proved to be a rapid and effective method for selecting fully silenced plants within 3 days. Furthermore, two novel phenotypes described are potential materials for in-depth investigations into the genes and mechanisms responsible for spontaneous transgene silencing.

• The Plant Pathology Journal
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• v.16 no.3
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• pp.130-136
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• 2000

Differences in physiological and biochemical responses between sensitive and tolerant rice cultivars to ozone were investigated to develop reliable indications of early ozone damage. Three Korean local rice cultivars -sen-sitive cultivar Dongjin (DJ), moderately tolerant cultivar Hwayeong (HY) and tolerant cultivar Ilmee (IM) were exposed to ozone at the concentrations of 100 nl $\textrm{l}^{-1}$ or 200 nl $\textrm{l}^{-1}$ , 8 h per day for 10 days in a controlled-environment fumigation chamber. The rice cultivars seemed to be endurable to ozone stress at the concentration of 100 nl $\textrm{l}^{-1}$ which is frequently monitored during the growing season in summer. However, severe damage was induced and differential sensitivity was clearly noted among the rice cultivars at the higher ozone concentration. Activation of the glutathion (GR) -ascorbate peroxidase (APX) cycle was likely to be responsible for protection of rice plants against ozone exposure, relating difference in sensitivity of rice cultivars to ozone. Photosynthetic activity appeared to be one of sensitive responses, for which chlorophyll fluorescence and leaf greenness can together provide a very reliable index, a degree of photosynthetic damages by ozone. Formation of malondialdehyde (MDA) was also considered as an indication that can differentiate cultivars sensitivity to ozone. However, the changes in polyamines and total phenolics were not consistent with exposed ozone concentrations and/or ozone sensitivity of the cultivars. The behavior of polyamines and phenolics in the damaged plants at high ozone levels could be interpreted as an indication of ozone injury rather than activation of additional protection mechanisms scavenging active oxygen species formed by ozone. Several responses triggered by ozone could explain the differential sensitivity of the rice cultivars and be used as reliable indications of relative ozone damage to rice plant.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.303-307
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• 2008

Cotyledon Black Decay (CBD) on soybean sprout mimics the black spot due to microbial infection. CBD, not visible or predictable at seedlot state, for some reason, shows up exclusively on cotyledon of soybean sprout during sprouting process. Such an incidence rate fluctuated from 0.8 to 19.5% over three years from 2004. We suspected some pod-infecting anthracnose fungi and/or pod-blight pathogen, or pod-sucking bean bug, one of the major pests of soybean, might have involved, of which we ruled out fungal pathogen because it was preventable through heat treatment, a proven method for seedlot disinfestation. The healthy seeds artificially fed by bean bug for one to seven days were sprouted, and 6 to 41% of the soybean sprout revealed the CBD mimic to those occurred in soybean sprout from previous commercial seedlot screening experiments. This finding is the first report to confirm that bean bug damage to pod at $R_8$ stage is directly responsible for the CBD, which did not concur with any other deleterious effects on sprouting such as reduction in hypocotyls elongation and rooting except unsightly sprout quality. However, earlier feeding either at green pod or greenish yellow pod stage ($R_6$ -early $R_7$ stage) resulted in rather severe damages, which strikingly reduced hypocotyls growth to about one forth to about two third, as well as the reduction in rates of seed germination.