• BMB Reports
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• v.42 no.6
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• pp.373-379
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• 2009

5-Hydroxyuridine (5-OHU) is a major lesion of uridine and cytosine produced in RNA by various chemical oxidants. To elucidate its biochemical and biophysical effects on RNA replication, the site-specifically modified oligoribonucleotides containing 5-OHU were synthesized with C5-hydroxy-5'-ODMTr-2'-TBDMS-uridine phosphoramidite using automated solid phase synthesis. The base-pairing properties of nucleotides opposite 5-OHU in 24 mer oligoribonulcleotides with dNTP were studied using three reverse transcriptases (Super-$Script^{TM}II$-, AMV-, MMLV-RT) in cDNA synthesis. Adenine as well as guanine was incorporated preferentially by all reverse transcriptases. In the UV-melting temperature experiment, the results from the relative stabilities of the base pairs were A : 5-OHU > G : 5-OHU > T : 5-OHU $\approx$ C : 5-OHU. Circular Dichroism (CD) studies showed that DNA-RNA containing 5- OHU heteroduplexes exhibit a similar conformation between the A-type RNA and B-type DNA. These results suggest that 5- OHU from oxidative damage was mainly influenced by adenine mismatch.

• Journal of Dental Anesthesia and Pain Medicine
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• v.23 no.3
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• pp.153-162
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• 2023

Background: Recent animal studies have suggested the role of GABA type A (GABA-_A) receptors in salivation, showing that GABA-_A receptor agonists inhibit salivary secretion. This study aimed to evaluate the effects of propofol (a GABA-_A agonist) on salivary secretions from the submandibular, sublingual, and labial glands during intravenous sedation in healthy volunteers. Methods: Twenty healthy male volunteers participated in the study. They received a loading dose of propofol 6 mg/kg/h for 10 min, followed by 3 mg/kg/h for 15 min. Salivary flow rates in the submandibular, sublingual, and labial glands were measured before, during, and after propofol infusion, and amylase activity was measured in the saliva from the submandibular and sublingual glands. Results: We found that the salivary flow rates in the submandibular, sublingual, and labial glands significantly decreased during intravenous sedation with propofol (P < 0.01). Similarly, amylase activity in the saliva from the submandibular and sublingual glands was significantly decreased (P < 0.01). Conclusion: It can be concluded that intravenous sedation with propofol decreases salivary secretion in the submandibular, sublingual, and labial glands via the GABA-_A receptor. These results may be useful for dental treatment when desalivation is necessary.

• Journal of Dental Anesthesia and Pain Medicine
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• v.23 no.4
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• pp.221-228
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• 2023

Background: We assessed the relationship between patient age and remifentanil dosing rate in patients managed under general anesthesia with spontaneous breathing using low-dose remifentanil in sevoflurane. Methods: The participants were patients with an American Society of Anesthesiologists Physical Status of 1 or 2 maintained under general anesthesia with low-dose remifentanil in 1.5-2.0% sevoflurane. The infusion rate of remifentanil was adjusted so that the spontaneous respiratory rate was half the rate prior to the induction of anesthesia, and γ^H (㎍/kg/min) was defined as the infusion rate of remifentanil under stable conditions where the respiratory rate was half the rate prior to the induction of anesthesia for ≥ 15 minutes. The relationship between γ^H and patient age was analyzed statistically by Spearman's correlation analysis. Results: During dental treatment under general anesthesia using low-dose remifentanil in sevoflurane, a significant correlation was detected between γ^H and patient age. The regression line of y = - 0.00079 x + 0.066 (y-axis; γ^H, x-axis; patient's age) was provided. The values of γ^H provide 0.064 ㎍/kg/min at 2 years and 0.0186 ㎍/kg/min at 60 years. Therefore, as age increases, the dosing rate exhibits a declining trend. Furthermore, in the dosing rate of remifentanil when the patient's respiratory rate was reduced by half from the preanesthetic respiratory rate, the dosing rate provided was around 0.88 mL/h in all ages if the remifentanil was diluted as 0.1 mg/mL. EtCO₂ showed 51.0 ± 5.7 mmHg, and SpO₂ was controlled within the normal range by this method. In addition, all dental treatments were performed without major problems, such as awakening and body movement during general anesthesia, and the post-anesthetic recovery process was stable. Conclusion: General anesthesia with spontaneous breathing provides various advantages, and the present method is appropriate for minimally invasive procedures.

• Anatomy and Cell Biology
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• v.56 no.2
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• pp.185-190
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• 2023

The root canal morphology undergoes aging-related changes, and relevant quantitative analyses have not yet been reported. We compared the cone beam computed tomography (CBCT) and micro-computed tomography (microCT) scans of extracted mandibular incisors to check the accuracy of morphological measurements. Thereafter, the root canal morphology and aging-related changes in the mandibular incisors of Japanese individuals were assessed using CBCT. Six extracted teeth were fixed in a phantom head and imaged using CBCT and micro-CT. The correlation between the findings of the two imaging modalities was examined. Further, CBCT reconstructed images of the mandibular incisors of 81 individuals were observed. Age-related changes of the root canals were compared between participants aged <30 years and those aged ≥30 years. The CBCT and micro-CT findings regarding the root canals of the extracted teeth coincided in 94.4% of the cases. Mandibular incisors exhibiting two root canals in either cross-section accounted for 9.9% of central incisors and 12.4% of lateral incisors. Mandibular central incisors with two root canals were observed in two (6.3%) individuals aged <30 years and six (12.2%) aged ≥30 years. Mandibular lateral incisors with two root canals were observed in one (3.1%) individual aged <30 years and nine (18.4%) aged ≥30 years. CBCT allows accurate evaluation of complex root canal morphologies and is useful for endodontic preoperative assessment. Mandibular incisors have more frequent occurrence of two root canals with aging.

• 축산식품과학과 산업
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• v.10 no.2
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• pp.37-41
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• 2021

• Anatomy and Cell Biology
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• v.56 no.3
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• pp.374-381
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• 2023

Although the epiglottis plays a vital role in deglutition, histological studies of the epiglottis and surrounding ligaments associated with swallowing dysfunction are limited. Therefore, we performed histological observations to clarify age-related changes in the morphological characteristics of the epiglottis and surrounding structures. Tissue samples comprising the epiglottis and surrounding structures were collected from corpses that were both orally fed and tubefed during their lifetimes. Following hematoxylin and eosin, Elastica Van Gieson, and immunohistochemical staining procedures, the chondrocytes, connective tissue, and glandular tissue were observed under the epiglottis epithelium, and intervening adipose tissue was observed in the surrounding area. Fatty degeneration of acinar cells was also observed in the glandular tissue, possibly because of aging. Bundles of elastic fibers were present around the vascular wall in the peri-epiglottic ligament, but some were reduced. Furthermore, large amounts of collagen fibers ran toward and through the cartilage, whereas the mesh-like elastic fibers stopped in front of the cartilage. Microfibrils considered to be oxytalan fibers, which are thinner and shorter than elastic fibers, were observed around the vascular wall and in the fiber bundles. Age-related changes included connective tissue fibrosis shown by the large amount of collagen fibers, atrophy of salivary glands, and an accompanying increase in adipose tissue. Regarding stretchability and elasticity, the elastic fibers may have an auxiliary function for laryngeal elevation during deglutition. This suggests that disuse atrophy of the laryngeal organs with or without oral intake might reduce the amount of elastic fiber in older adults.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.3
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• pp.182-192
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• 1994

This paper focuses on the investigation of the heat transfer phenomena that occur inside the cylindrical tube. The inclination of the tube is adopted as a principal parameter varying from vertical to horizontal. The phase change material employed in this experiment is 99 percent pure n-docosane paraffin($C_{22}$ $H_{46}$). It is found that the amount of solidified mass during a prescribed solidifying period is not sensitive to the inclination of the tube but to the local layer thickness. It is studied that the latent energy is the largest contributor to the total extracted energy. The sensible energy($E_{s1}$, $E_{s2}$, $E_{s3}$) may not be negligible at the large wall-subcooling and initial-liquid-superheating, also at the first step of solidifying.

• Journal of the Korean Society of Combustion
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• v.1 no.2
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• pp.31-39
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• 1996

This study was carried out to delvelop the burner for condensing gas boiler which can save energy by utilizing latent heat of combustion gas. A perforated can-type burner adopting premixed flame was chosen to reduce NOx emission and to simplify the manufacturing process. Basic experiments using unit cell combustor have been conducted to obtain data about the design parameters of perforated burner surface which can make stable flame for a wide operating conditions. Can-type burners designed on the basis of above data shows that flames are stable and also CO and NOx emission are low for a wide operating range.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.6
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• pp.18-28
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• 1994

An exhaust-heated gas turbine cycle equipped with a waste heat recovery boiler and ammonia absorption-type refrigerator using waste heat is newly devised and analyzed. The general performance of this cycle is compared with that of the conventional gas turbine cycle. This cycle shows a potential high efficiency. When 1500K of gas turbine inlet temperature the efficiency is 53 percent as compared to 45 percent for a conventional combined cycle. Suction cooling of this cycle leads to improve the thermal efficiency and the specific output.

• Journal of Korean Medicine Rehabilitation
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• v.21 no.1
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• pp.97-114
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• 2011

Objectives : The object of this study is to observe the favorable anti arthritic effects of Sowhalrack-dan($Xi\check{a}ohu\acute{o}lu\grave{o}-d\bar{a}n$)(SWRD), which has been traditionally used in Korean medicine to treat rheumatoid arthritis on Freund's complete adjuvant(FCA) induced arthritic Wistar rats. Methods : Rheumatoid arthritis was induced by intradermal injection of FCA(10 mg in 1 ml paraffin oil 0.1 ml/rats). Each of 8 rats showing regular ankle circumferences per group were selected in 14 days after FCA treatment to confirm the induction of rheumatoid arthritis. 300, 150 or 75 mg/kg of SWRD was orally administered once a day for 14 days from 14 days after FCA treatments. Dexamethasone was intraperitoneally administered 15 mg/kg, once a day for 14 days from 14 days after FCA treatments. Rats were sacrificed after 14 days of continuous oral treatment of SWRD or intraperitoneal administration of dexamethasone, and changes were observed; the body weight, knee circumferences, gross arthritis score, inflammatory tissue $prostaglandin(PG)E_2$ levels and cartilage collagen, glucosaminoglycans compositions - chondroitin sulphate, heparin sulphate and hyaluronic acid in the present study. Results : As results of FCA treatment, classic rheumatoid arthritis featuring dramatical decreases on the body weights, cartilage collagen contents and bone glucosaminoglycans - chondroitin sulphate, heparin sulphate and hyaluronic acid contents. Also, it increases the knee circumferences, gross arthritis scores and inflammatory tissue $PGE_2$ levels. However, these changes from FCA induced rheumatoid arthritis were clearly reduced due to the dexamethasone and both two different dosages of SWRD, 300 and 150 mg/kg in the present study. Although FCA induced arthritis were more favorably inhibited by treatment of dexamethasone 15 mg/kg compared to SWRD 300 mg/kg, marked decreases of body weights were detected in dexamethasone 15 mg/kg treated rats. Conclusions : The results obtained in this study suggest that over 150 mg/kg of SWRD showed favorable anti-arthritic effects on the FCA induced arthritis mediated by suppression of $PGE_2$. However, detailed mechanism studies are needed with the screening of the biological active compounds in SWRD. Although FCA induced arthritis were more favorably inhibited by treatment of dexamethasone 15 mg/kg compared to SWRD 300 mg/kg, marked decreases of body weights were detected in dexamethasone 15 mg/kg treated rats, in the present study.