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

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.11 no.3
• /
• pp.184-191
• /
• 2023

With increasing corrosion in RC (Reinforced Concrete) structures, cracks occurred due to corrosion products and bearing load resistance decreased. In this study, corrosion was induced through an accelerated corrosion test (ICM: Impressed Current Method) with 140 hours of duration, and changes in USV (Ultra-Sonic Velocity), flexural failure load, and corrosion weight were evaluated before and after corrosion test. Three levels of cover depth (20 mm, 30 mm, and 40 mm) were considered, and the initial cracking period increased and the rust around steel decreased with increasing cover depth. In addition, the USV linearly decreased with decreasing cover depth and increasing amount of corrosion. In the flexural loading test, the bending capacity decreased by more than 10% due to corrosion, but a clear correlation could not be obtained since the corrosion ratio was small, so that the effect of slip was greater than that of reduced cross-sectional area of steel due to corrosion. As cover depth increased, the produced corrosion amount and USV changed with a clear linear relationship, and the cracking period due to corrosion could be estimated by the gradient of the measured corrosion current.

• KDI Journal of Economic Policy
• /
• v.12 no.4
• /
• pp.21-46
• /
• 1990

This paper, a sequel to Yoo and Lee (1990), attempts to investigate the interindustry determinants of technical efficiency in Korea's manufacturing industries, and also to conduct an exploratory analysis on the stability of technical efficiency over time. The hypotheses set forth in this paper are most found in the existing literature on technical efficiency. They are, however, revised and shed a new light upon, whenever possible, to accommodate any Korea-specific conditions. The set of regressors used in the cross-sectional analysis are chosen and the hypotheses are posed in such a way that our result can be made comparable to those of similar studies conducted for the U.S. and Japan by Caves and Barton (1990) and Uekusa and Torii (1987), respectively. It is interesting to observe a certain degree of similarity as well as differentiation between the cross-section evidence on Korea's manufacturing industries and that on the U.S. and Japanese industries. As for the similarities, we can find positive and significant effects on technical efficiency of relative size of production and the extent of specialization in production, and negative and significant effect of the variations in capital-labor ratio within industries. The curvature influence of concentration ratio on technical efficiency is also confirmed in the Korean case. There are differences, too. We cannot find any significant effects of capital vintage, R&D and foreign competition on technical efficiency, all of which were shown to be robust determinants of technical efficiency in the U.S. case. We note, however, that the variables measuring capital vintage effect, R&D and the degree of foreign competition in Korean markets are suspected to suffer from serious measurement errors incurred in data collection and/or conversion of industrial classification system into the KSIC (Korea Standard Industrial Classification) system. Thus, we are reluctant to accept the findings on the effects of these variables as definitive conclusions on Korea's industrial organization. Another finding that interests us is that the cross-industry evidence becomes consistently strong when we use the efficiency estimates based on gross output instead of value added, which provides us with an ex post empirical criterion to choose an output measure between the two in estimating the production frontier. We also conduct exploratory analyses on the stability of the estimates of technical efficiency in Korea's manufacturing industries. Though the method of testing stability employed in this paper is never a complete one, we cannot find strong evidence that our efficiency estimates are stable over time. The outcome is both surprising and disappointing. We can also show that the instability of technical efficiency over time is partly explained by the way we constructed our measures of technical efficiency. To the extent that our efficiency estimates depend on the shape of the empirical distribution of plants in the input-output space, any movements of the production frontier over time are not reflected in the estimates, and possibilities exist of associating a higher level of technical efficiency with a downward movement of the production frontier over time, and so on. Thus, we find that efficiency measures that take into account not only the distributional changes, but also the shifts of the production frontier over time, increase the extent of stability, and are more appropriate for use in a dynamic context. The remaining portion of the instability of technical efficiency over time is not explained satisfactorily in this paper, and future research should address this question.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.25 no.6
• /
• pp.1061-1068
• /
• 2011

Moxibustion is a treatment method for cold and pain in Korean medicine. But the systematic study of moxibustion were very few. This study was aimed to survey and evaluate moxibustion study in Korean medicine. We search the moxibustion study in journals related Korean medicine and http://oasis.kiom.re.kr. The period of the study from first issue to August, 2010. The search word were moxibustion, moxa in keyword and moxibustion treatment in title. We totally search 334 articles. But 175 articles were excluded because this study were not exactly moxibustion study, so we included and analyzed 159 articles. The study of moxibustion were 159 articles. Literature review were 35 articles, systematic review 8, heat experiment 10, in vivo or vitro 28 and survey investigation 3. Clinical articles of moxibustion related to Korean medical journals were 76. Before and after study were 31 articles, case report 20, cohort study 7, cross-sectional study 2, nonrandomized study 6, quasi randomized study 1, randomized clinical trials 9. This results showed that moxibustion study were smaller than acupuncture or herb and concentrated to pain and cold syndrome. We need further larger and diverse study of moxibustion.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.222-222
• /
• 2012

Metal oxide gas sensors based on semiconductor type have attracted a great deal of attention due to their low cost, flexible production and simple usability. However, most works have been focused on n-type oxides, while the characteristics of p-type oxide gas sensors have been barely studied. An investigation on p-type oxides is very important in that the use of them makes possible the novel sensors such as p-n diode and tandem devices. Monoclinic cupric oxide (CuO) is p-type semiconductor with narrow band gap (~1.2 eV). This is composed of abundant, nontoxic elements on earth, and thus low-cost, environment-friendly devices can be realized. However, gas sensing properties of neat CuO were rarely explored and the mechanism still remains unclear. In this work, the neat CuO layers with highly ordered mesoporous structures were prepared by a template-free, one-pot solution-based method using novel ink solutions, formulated with copper formate tetrahydrate, hexylamine and ethyl cellulose. The shear viscosity of the formulated solutions was 5.79 Pa s at a shear rate of 1 s-1. The solutions were coated on SiO2/Si substrates by spin-coating (ink) and calcined for 1 h at the temperature of $200{\sim}600^{\circ}C$ in air. The surface and cross-sectional morphologies of the formed CuO layers were observed by a focused ion beam scanning electron microscopy (FIB-SEM) and porosity was determined by image analysis using simple computer-programming. XRD analysis showed phase evolutions of the layers, depending on the calcination temperature, and thermal decompositions of the neat precursor and the formulated ink were investigated by TGA and DSC. As a result, the formation of the porous structures was attributed to the vaporization of ethyl cellulose contained in the solutions. Mesoporous CuO, formed with the ink solution, consisted of grains and pores with nano-meter size. All of them were strongly dependent on calcination temperature. Sensing properties toward H2 and C2H5OH gases were examined as a function of operating temperature. High and fast responses toward H2 and C2H5OH gases were discussed in terms of crystallinity, nonstoichiometry and morphological factors such as porosity, grain size and surface-to-volume ratio. To our knowledge, the responses toward H2 and C2H5OH gases of these CuO gas sensors are comparable to previously reported values.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.24 no.4
• /
• pp.536-546
• /
• 2014

Objectives: The major objective of this paper is compare the exposure work hours and experieence of ill health symptoms among under and over employment and matched group. Workers with over employment have more exposed to hazards than that with under employment because that workers with over employment work more than those with ender employment. Methods: This study as heuristics one used the third Korean Working Conditions Survey done by Occupational Safety and Health Research Institute in 2011. The sample size is 50,023 economic active persons. Over and under employment were measured by matching method of preferred and actual work hours. The exposed work hours to hazards were measured according to 13 hazardous factors and the experience of ill health symptoms were scaled by the number of experienced 14 ill health symptoms. To compare the exposure and the symptoms experience were compared by mean difference test with F test. Results: The proportion of over employment in male employees is 32.1% and that in female employees is 29.3% and under employment rate is 11.2% in mae and 13.9% in female employees. There is significant difference of the rate of over and under emplyment among age groups, industrial sectors, occupational groups and the state of employment. The difference of the exposed work hours to hazards among under, over and matched group were statistically significant in all hazards by gender. The exposed work hours to hazards in over employment were more than those in under employment. The number of experienced symptoms in over employment is statistically significantly more than that in under employment. Conclusions: Workers with over employment may be vulnerable group in the criteria of hazard exposure and health status. The results have some implications and limitations because that this study is heuristic one. The mismatch of preferred and actual working hours may be unfavorable work condition that has impact on safety and health of workers. The impact mechanism may be investigated as future study, Because that this study used cross sectional survey data, some causal relationships cannot be evaluated.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.14 no.4
• /
• pp.437-445
• /
• 2007

Purpose: The purpose of this study was to identify levels of knowledge, perception, and practice of eye care as part of nursing care in the ICU. Method: A descriptive, cross-sectional study design was used. The participants in this study were 269 registered nurses working in the ICUs of five university hospitals in Seoul, Korea. Between November 2005 and December 2005, data were collected using a semi-structured questionnaire developed by the researchers, and analyzed using the SPSS Program. Results: In general, levels of knowledge of nursing care for the eyes were moderate among ICU nurses, but levels of perception of nursing care for the eyes were very high. Of the respondents, 61.7% reported that they would consult a doctor whenever they found an eye problem. Only 42.4% nurses answered that they provide eye care as part of the daily routine and 43.9% nurses responded that they cleanse the eye lids with wet saline gauze. In regression analysis, the practice of eye care as part of nursing was significantly influenced by perception of nursing care for the eyes, and knowledge of interventions for nursing care for the eyes. Conclusion: These results suggest that education on care of the eyes for ICU nurses and the development of a standardized eye care protocol should be done to improve quality of nursing care in the ICU.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.19
• /
• pp.8063-8067
• /
• 2014

Background: Cervical cancer is a major public health problem in Bangladesh. Persistence of high risk human papillomavirus (HRHPV) influences the progression of the disease, with an important role in followup for cervical intraepithelial neoplasia (CIN). Objective: To establish application of high risk HPV DNA test in the follow-up of women after treatment of CIN. Materials and Methods: This cross-sectional and hospital based study was carried out among 145 CIN treated women during the previous six months to three years at the colposcopy clinic of Bangabandhu Sheikh Mujib Medical University, Dhaka, between January 2011 and June 2012. Pap smear and HPV samples were collected and colposcopy was performed to find out the persistence of the disease. Cervical samples obtained were tested for HPV DNA using the Hybrid Capture II (HC-II) test. A cervical biopsy was collected whenever necessary. The results were compared to assess the efficacy of different methods during follow up such as Pap smear, HPV test and colposcopy. Results: Mean age of the recruited women (n=145) was 33.6 (${\pm}7.6$), mean age of marriage was 16.8 (${\pm}2.9$) and mean age of 1st delivery was 18.8 (${\pm}3.5$) years. More than half had high grade CIN before treatment and 115 (79.3%) women were managed by LEEP and 20.7% were managed by cold coagulation. Among the 145 treated women, 139 were negative for HPV DNA and six of them (4.1%) were HPV positive. Sensitivity of Pap smear (40.0) and HPV DNA test (40.0) was poor, but specificity was quite satisfactory (>93.0) for all the tests. Conclusions: The high risk HPV DNA test can be an effective method of identifying residual disease. It can be added to colposcopy and this should be applied to all treated women attending for their first or second post-treatment follow-up visit at 6 months to one year, irrespective of the grade of treated CIN.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.19
• /
• pp.8183-8189
• /
• 2014

Background: A comparative cross-sectional study involving oral cancer patients and healthy individuals was designed to investigate associations between retinol, ${\alpha}$-tocopherol and ${\beta}$-carotene with the risk of oral cancer. Materials and Methods: This study included a total of 240 matched cases and controls where subjects were selected from the Malaysian Oral Cancer Database and Tissue Bank System (MOCDTBS). Retinol, ${\alpha}$-tocopherol and ${\beta}$-carotene levels and intake were examined by high-performance liquid chromatography (HPLC) and food frequency questionnaire (FFQ) respectively. Results: It was found that results from the two methods applied did not correlate, so that further analysis was done using the HPLC method utilising blood serum. Serum levels of retinol and ${\alpha}$-tocopherol among cases ($0.177{\pm}0.081$, $1.649{\pm}1.670{\mu}g/ml$) were significantly lower than in controls ($0.264{\pm}0.137$, $3.225{\pm}2.054{\mu}g/ml$) (p<0.005). Although serum level of ${\beta}$-carotene among cases ($0.106{\pm}0.159{\mu}g/ml$) were lower compared to controls ($0.134{\pm}0.131{\mu}g/ml$), statistical significance was not observed. Logistic regression analysis showed that high serum level of retinol (OR=0.501, 95% CI=0.254-0.992, p<0.05) and ${\alpha}$-tocopherol (OR=0.184, 95% CI=0.091-0.370, p<0.05) was significantly related to lower risk of oral cancer, whereas no relationship was observed between ${\beta}$-carotene and oral cancer risk. Conclusions: High serum levels of retinol and ${\alpha}$-tocopherol confer protection against oral cancer risk.

• Journal of the Microelectronics and Packaging Society
• /
• v.22 no.3
• /
• pp.31-38
• /
• 2015

In order to achieve a high speed and high quality silicon wafer bonding, the room-temperature direct bonding using atmospheric pressure plasma and sprayed water vapor was developed. Effects of different plasma fabrication parameters, such as flow rate of $N_2$ gas, flow rate of CDA (clear dry air), gap between the plasma head and wafer surface, and plasma applied voltage, on plasma activation were investigated using the measurements of the contact angle. Influences of the annealing temperature and the annealing time on bonding strength were also investigated. The bonding strength of the bonded wafers was measured using a crack opening method. The optimized condition for the highest bonding strength was an annealing temperature of $400^{\circ}C$ and an annealing time of 2 hours. For the plasma activation conditions, the highest bonding strength was achieved at the plasma scan speed of 30 mm/sec and the number of plasma treatment of 4 times. After optimization of the plasma activation conditions and annealing conditions, the direct bonding of the silicon wafers was performed. The infrared transmission image and the cross sectional image of bonded interface indicated that there is no void and defects on the bonded wafers. The bonded wafer exhibited a bonding strength of average $2.3J/m^2$.