• Bulletin of the Korean Chemical Society
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• v.13 no.5
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• pp.486-491
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• 1992

The rate constants for the reactions of p-nitrophenyl acetate with 6 different aryloxides and 2 benzohydroxamates have been measured spectrophotometrically in water containing various concentrations of cetyltrimethylammonium bromide (CTAB). The reactivity of the nucleophiles has been demonstrated to be significantly enhanced as the concentration of the surfactant increases up to a certain point. When the basicities of the aryloxides are comparable, the rate enhancement is more prominent for the aryloxide having larger binding constant to the micellar aggregate. Benzohydroxamates exhibitis significantly large ${\alpha}$-effect in the absence of the surfactant, although, the ${\alpha}$-effect nucleophiles are considered to be more solvated in water than the corresponding normal nucleophile. Thus, the solvation effect does not appear to be solely responsible for the ${\alpha}$-effect. Interestingly, the large ${\alpha}$-effect disappears in the presence of the surfactant. Therefore, one might attribute the disappearance of the ${\alpha}$-effect to solvent effect. However, a structural change of the reactive ${\alpha}$ -effect nucleophile into unreactive ones would also be considered to be responsible for the absence of the ${\alpha}$-effect in the present system.

• BMB Reports
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• v.52 no.10
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• pp.607-612
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• 2019

During meiosis, programmed double-strand breaks (DSBs) are repaired via recombination pathways that are required for faithful chromosomal segregation and genetic diversity. In meiotic progression, the non-homologous end joining (NHEJ) pathway is suppressed and instead meiotic recombination initiated by nucleolytic resection of DSB ends is the major pathway employed. This requires diverse recombinase proteins and regulatory factors involved in the formation of crossovers (COs) and non-crossovers (NCOs). In mitosis, spontaneous DSBs occurring at the G1 phase are predominantly repaired via NHEJ, mediating the joining of DNA ends. The Ku complex binds to these DSB ends, inhibiting additional DSB resection and mediating end joining with Dnl4, Lif1, and Nej1, which join the Ku complex and DSB ends. Here, we report the role of the Ku complex in DSB repair using a physical analysis of recombination in Saccharomyces cerevisiae during meiosis. We found that the Ku complex is not essential for meiotic progression, DSB formation, joint molecule formation, or CO/NCO formation during normal meiosis. Surprisingly, in the absence of the Ku complex and functional Mre11-Rad50-Xrs2 (MRX) complex, a large portion of meiotic DSBs was repaired via the recombination pathway to form COs and NCOs. Our data suggested that Ku complex prevents meiotic recombination in the elimination of MRX activity.

• Journal of Korean society of Dental Hygiene
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• v.21 no.5
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• pp.611-620
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• 2021

Objectives: This study investigated health behavior and nutritional status according to the presence or absence of periodontal disease using data from the Sixth National Health Nutrition Survey. Methods: Data from the 2013-2015 National Health Nutrition Survey were analyzed by frequency analysis, chi-square test, and Pearson's correlation analysis using SPSS 21.0. Results: Periodontal disease was more frequent in the group of patients who perceived that their subjective health status was "very bad" or were underweight according to the BMI classification. In men, periodontal disease occurred more frequently in those who were taking calcium (p<0.05), and periodontal disease occurred more frequently in the age group of 20-39, regardless of sex (p<0.05). In women, periodontal disease was less frequent in the group taking vitamin A. In both men and women, the presence of periodontal disease correlated with high fasting blood sugar and glycated hemoglobin levels. Conclusions: A customized program should be developed for each patient to identify factors that affect the relationship among periodontal disease, nutrient intake, and blood parameters. Such information will help improve the oral health of the population.

• Hip & pelvis
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• v.30 no.4
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• pp.197-201
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• 2018

In Western patient populations, the reported incidence of imaging-demonstrated deep vein thrombosis (DVT) after total hip arthroplasty (THA) is as high as 70% without prophylaxis. The reported rates of symptomatic pulmonary embolism (PE) after THA in recent studies range from 0.6% to 1.5%, and the risk of fatal PE ranges from 0.11% to 0.19% in the absence of prophylaxis. Predisposing factors to DVT in western patients include advanced age, previous venous insufficiency, osteoarthritis, obesity, hyperlipidemia, dietary and genetic factors. However, Asian patients who have undergone THA have a strikingly low prevalence of DVT and virtually no postoperative PE. Some authors suggest low clinical prothrombotic risk factors and the absence of some DVT-related genetic factors in Asian patient populations decrease the risk of DVT, PE or both. In Korea, the prevalence of DVT after THA without thromboprophylaxis have ranges from 6.8% to 43.8%, and asymptomatic PE have ranges from 0% to 12.9%; there have been only two reported cases of fatal PE. Deep-wound infections resulting from postoperative hematomas or prolonged wound drainage have been reported with routine thromboprophylaxis. The prevalence of DVT differs varies based on patient ethnicity. Guidelines for the use of thromboprophylaxis were altered and focus on the potential value of outcomes compared with possible complications (e.g., bleeding).

• Journal of Korean Society of Archives and Records Management
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• v.18 no.4
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• pp.25-43
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• 2018

As nonexisting information affects actual information release rate, the study noted that the absence of records leads to the "nonexistence of information." Therefore, in this research, it was argued that records management should be thoroughly controlled from the stage of record production to solve problems such as the loss/damage/neglect/destruction/misclassification/ reduction of preservation periods and more. Through the management from the production stage, it is expected that the nonexistence of information problem will not occur and can be used as a tool for a demonstration of why the nonexistence of information exists even if such information occurs.

• Anatomy and Cell Biology
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• v.51 no.4
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• pp.243-250
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• 2018

Because of its embryonic origin, the thyroid gland is predisposed to multiple anatomical variations and developmental anomalies. These include the pyramidal lobe, the origin of levator glandular thyroidae, the absence of the isthmus, ectopic thyroid, accessory thyroid tissues, etc. These anatomical variations are clinically significant to surgeons, anatomists, and researchers. The present study was designed to report anatomical variations and developmental anomalies of the thyroid gland in Ethiopian population. The study was conducted on 40 cadavers used for routine dissection classes. The thyroid gland was exposed and observed for any variations and developmental anomalies. The length, width, and thickness of the lobes were measured using a vernier caliper. Differences in the incidence of pyramidal lobe and absence of the isthmus between sexes were tested using a Pearson chi-square test. The mean length, width, and thickness of the right lobe were 4.24 cm, 1.8 cm, and 1.6 cm, respectively, whereas it was 4.08 cm, 1.8 cm, and 1.6 cm, respectively for that of the left lobe. The pyramidal lobe was noted in 52.5% of the cadavers. The levator glandulae thyroidae were prevalent in 40% of the cadavers. The isthmus mainly overlies the 2nd to 4th tracheal rings and was absent in 7.5% of the cadavers. Accessory thyroid tissue and double pyramidal lobes were noted in 2.5% of the cadavers. Most of the variations of the thyroid gland were seen frequently in female but it was not statically significant. Different clinically important and rare variations of the thyroid gland were found.

• Imaging Science in Dentistry
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• v.49 no.3
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• pp.213-218
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• 2019

Purpose: The aim of this study was to evaluate the relationship between the mandibular canal and impacted mandibular third molars using cone-beam computed tomography (CBCT) and to compare the CBCT findings with signs on panoramic radiographs(PRs). Materials and Methods: This retrospective study consisted of 200 mandibular third molars from 200 patients who showed a close relationship between the mandibular canal and impacted third molars on PRs and were referred for a CBCT examination of the position of the mandibular canal. The sample consisted of 124 females and 76 males, with ages ranging from 18 to 47 years (mean, $25.75{\pm}6.15$ years). PRs were evaluated for interruption of the mandibular canal wall, darkening of the roots, diversion of the mandibular canal, and narrowing of the mandibular canal. Correlations between the PR and CBCT findings were statistically analyzed. Results: In total, 146 cases(73%) showed an absence of canal cortication between the mandibular canal and impacted third molar on CBCT images. A statistically significant relationship was found between CBCT and PR findings (P<0.05). The absence of canal cortication on CBCT images was most frequently accompanied by the PR sign of diversion of the mandibular canal(96%) and least frequently by interruption of the mandibular canal wall(65%). Conclusion: CBCT examinations are highly recommended when diversion of the mandibular canal is observed on PR images to reduce the risk of mandibular nerve injury, and this sign appears to be more relevant than other PR signs.

• Bulletin of the Korean Chemical Society
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• v.10 no.4
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• pp.339-343
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• 1989

The interaction of cationic surfactants, n-alkyltrimethylammonium bromide ($C_nTAB$; n = 12, 14, 16) with anionic polyelectrolyte, poly(styrenesulfonate) (PSS) has been studied by surface tension measurement. In the absence of added salt, the cationic surfactants bind to PSS quantitatively up to ca. 60% coverage of anionic sites of the polyanion and the complexes were surface inactive. Further binding of the surfactant cations on PSS caused a sharp conformational transition of the surfactant/ PSS complexes to surface active complexes and accompanied precipitation. The binding showed a biphasic behavior in the presence of NaCl and cooperativity of the binding became less as the concentration of NaCl increased. Binding of the cationic surfactants on poly(vinylsulfonate) also showed the biphasic behavior and the cooperativity of the binding was much less even in the absence of NaCl. The binding of surfactant to PSS provided hydrophobic environment to solubilized pyrene and reduced the viscosity of the solution greatly even at surfactant concentrations well below cmc. This study indicated that the surfactant bound to PSS up to $60{\%}$ coverage of PSS sites are present as surfactant aggregates which are wrapped up with PSS chains, and hydrophobic interaction is an important factor in the binding of the surfactants to PSS.

• Safety and Health at Work
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• v.13 no.2
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• pp.201-206
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• 2022

Background: The present objective was to verify whether burnout (emotional exhaustion [EE], depersonalization [DP] and low professional efficacy [PE]) is a risk factor for long-term sickness absence (LTSA; 30 consecutive days) from the teaching role. Methods: This was a prospective cohort study with two years of follow-up that investigated 509 elementary and high-school teachers. Burnout was identified by Maslach Burnout Inventory. Poisson regression with robust variance was used to adjust for possible confounders. Results: The incidence of LTSA was 9.4%. High EE levels were associated with LTSA in the crude analysis, but the association lost statistical significance after adjustments (for sex, age, perception of work-life balance, general self-rated health, chronic pain and depression). High DP levels were associated with this outcome, even after all adjustments (relative risk = 1.80; 95% confidence interval: 1.05-3.09). Low PE levels were not related to LTSA. Conclusion: The results reinforce the need to improve teachers' work conditions to reduce burnout, particularly DP, and its consequences.

• Physical Therapy Rehabilitation Science
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• v.11 no.2
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• pp.154-164
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• 2022

Objective: The purpose of this study is to select a cognitive training game that can evaluate five cognitive domains and to study their validity with existing cognitive evaluation tools. Design: Methods: Delphi survey was conducted through the 2nd questionnaire for 30 experts to select games suitable for training 5 cognitive domains. Five cognitive training games and Mini Mental State Examination - Korea(MMSE-K), and cognitive impairment screening test(CIST) were conducted for 82 elderly in the community. Pearson correlation analysis was performed to find out the correlation of the three tests. The ROC curve was used to calculate the selection criteria for the game results for the screening evaluation of the presence or absence of mild cognitive impairment. Results: The coefficient of variation to evaluate the stability of the Delphi survey was less than 0.50 in most game items. The 'correct answers' and 'level' of the five final selected game items showed a statistically significant positive correlation with the CIST and MMSE-K scores. CIST score and 'time' of all game items except 'number making_time' showed a statistically significant negative correlation. Conclusions: The validity of the cognitive training program using smart devices was evaluated, and the criteria for classifying the cognitive domain and distinguishing the presence or absence of cognitive impairment were confirmed.