• Restorative Dentistry and Endodontics
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• v.24 no.4
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• pp.623-627
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• 1999

During canal instrumentation of a curved canal, restoring force of endodontic instrument remove more dentin from the inner wall of the curvature. This effect tends to straighten the canal and thus may significantly shorten the working length. This study was to determine the mean reduction in working length after instrumentation according to the curvature. The curvature of mandibular mesial root was determined before instrumentation. 30 canals were divided into 3 groups each 10 on the basis of degree of curvature. Experimental groups as follows. In group 1, canals having curvature from 15 to 20 degrees: in group 2, canals having curvature from 20 to 30degrees; in group 3, canals having curvature above 30 degrees. Experimental teeth in all groups were accessed, and their actual working length determined by passing a size 15 K-file(IAF) just through the minor apical foramen. The canals were sequentially enlarged to size 35 with ProFile .06 series. The change of working length was calculated by measuring the tip of IAF beyond apical foramen by using stereomicroscope. The change of canal curvature following instrumentation were measured using the Schneider technique. The results were as follows. 1. The greatest changes of curvature and working length were observed in the group 3 canals(P<0.05), next were group 2 canals and group 1 canals(P>0.05). 2. Group 1 canals showed a mean reduction in 1.61 degrees and length of 0.12m respectively(P>0.05). 3. Group 2 canals showed a mean reduction in 3.42 degrees(P<0.05) and length of 0.25mm(P>0.05) respectively. 4. Group 3 canals showed a mean reduction in 7.23 degrees(<0.05) and length of 0.64mm respectively(P<0.05).

• Annals of Clinical Neurophysiology
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• v.5 no.1
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• pp.21-26
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• 2003

Background & Objectives: Hyperexcitablity of motor system is a well-established characteristic pathophysiologic finding of amyotrophic lateral sclerosis (ALS). Whereas little is known about the source of excitability according to the progression of the disease. We evaluated the excitability and its source in advanced ALS patients using transcranial magnetic stimulation (TMS). Meterial & Methods: Motor evoked potentials (MEP) by TMS were recorded for abductor pollicis brevis muscles in 20 patients, 11 men and 9 women, with ALS. Mean age was $54.2{\pm}12.1years$, and mean disease duration was $13.9{\pm}13.4years$. Serial magnetic stimulations were applied to get the parameters; excitability threshold (ET), amplitude and latency of MEP. We also had a facilitated MEP (fMEP). Results: The parameters were analyzed according to the clinical settings. ET was higher in ALS(mean $63.5{\pm}18.1$) than normal control (mean $46.0{\pm}8.4$, p<0.01). Amplitudes of MEP were reduced in ALS ($2.6{\pm}3.6mV$; control $6.5{\pm}3.1mV$, p<0.01). Duration of the disease and ET showed significant inverse correlation (Spearson correlation coefficient = -0.57, p<0.01). Duration of the disease and fMEP/MEP ratio showed less but also significant inverse correlation (Spearson correlation coefficient, r = -0.52, p < 0.05). Conclusions: Lower ET in advanced ALS patients, in spite of decreased fMEP/MEP ratio, may indicate the hyperexcitability of lower motor neurons in these patients. This study suggests that lower motor neurons is hyperexcitable due to upper motor neuron dysfunction at advanced stage.

• Women's Health Nursing
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• v.11 no.3
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• pp.218-224
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• 2005

Purpose: The Purpose of this study was to investigate the relationship between state anxiety and maternal fetal attachment of unmarried mothers in a welfare center. Methods: The subjects were 25 unmarried mothers in a welfare center. The data was collected through personal interviews using a questionnaire. The instruments used for this study were the modified Spielberger's state anxiety inventory and Cranley's Maternal-Fetal Attachment Scale. Data was analyzed descriptive statistics, mean, standard deviation, t-test and the pearson correlation coefficient with the SPSS computer program. Results: The age of the subjects ranged from 15 to 25, and their average age was 20.0. The mean score of state anxiety was 58.2. There was significant difference in the degree of maternal state anxiety between the group whose pregnancy was known by their family and the group whose pregnancy was hidden. The group whose pregnancy was known showed a low state anxiety score. There was a significant difference in the degree of maternal state anxiety by the gestational period. The group who were in the second and third gestational trimester showed lower state anxiety score than in the first trimester. The mean score of maternal-fetal attachment(MFA) was 64.9. There were significant differences in the degree of maternal fetal attachment, by an ultrasound scan experience. The most frequently practiced attachment item was "I think the fetus is able to feel(mean 3.8)". Unmarried mothers degree of state anxiety showed a negative correlation with the degree of maternal fetal attachment(r=-.25), but there was no significant difference between the two variables. Conclusions: The unmarried mothers made an effort in striving to reduce their high state anxiety and to enhance maternal fetal attachment. They also realize how to take care of their state anxiety.

• Imaging Science in Dentistry
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• v.52 no.1
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• pp.43-51
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• 2022

Purpose: The aim of this study was to evaluate the reliability of the Vectra M3 (3D Imaging System; Canfield Scientific, Parsippany, NJ, USA) in detecting chin asymmetry, and to assess whether the automatic markerless tracking function is reliable compared to manually plotting landmarks. Materials and Methods: Twenty subjects (18 females and 2 males) with a mean age of 42.5±10.5 years were included. Three-dimensional image acquisition was carried out on all subjects with simulated chin deviation in 4 stages (1-4 mm). The images were analyzed by 2 independent observers through manually plotting landmarks and by Vectra software auto-tracking mode. Repeated-measures analysis of variance and the Tukey post-hoc test were performed to evaluate the differences in mean measurements between the 2 operators and the software for measuring chin deviation in 4 stages. The intraclass correlation coefficient (ICC) was calculated to estimate the intra- and inter-examiner reliability. Results: No significant difference was found between the accuracy of manually plotting landmarks between observers 1 and 2 and the auto-tracking mode (P=0.783 and P=0.999, respectively). The mean difference in detecting the degree of deviation according to the stage was <0.5 mm for all landmarks. Conclusion: The auto-tracking mode could be considered as reliable as manually plotted landmarks in detecting small chin deviations with the Vectra^® M3. The effect on the soft tissue when constructing a known dental movement yielded a small overestimation of the soft tissue movement compared to the dental movement (mean value<0.5 mm), which can be considered clinically non-significant.

• Journal of Power System Engineering
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• v.4 no.4
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• pp.25-31
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• 2000

This paper represents the vector fields and three dimensional mean velocities in the X-Y plane of cone type swirl gas burner measured by using X-probe from the hot-wire anemometer system. This experiment is carried out at flowrate 350 and $450{\ell}/min$ respectively in the test section of subsonic wind tunnel. The vector plot shows that the maximum axial mean velocity component is focused in the narrow slits distributed radially on the edge of a cone type swirl burner, for that reason, there is some entrainment of ambient air in the outer region of the burner and the rotational flow can be shown in the inner region of the burner because mean velocity W is distributed about twice as large as mean velocity V due to inclined flow velocity ejecting from the swirl vanes of a cone type baffle plate of burner. Moreover, the mean velocities are largely distributed near the outer region of burner within $X/R{\fallingdotseq}1.5$, hence, the turbulent characteristics are anticipated to be distributed largely in the center of this region due to the large inclination of mean velocity and swirl effect.

• The Journal of Korean Society for Radiation Therapy
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• v.33
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• pp.89-97
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• 2021

Purpose: The purpose of this study is to compare and evaluate the dose change according to the gas volume variations in the rectum, which was not included in the treatment plan during radiation therapy for cervical cancer. Materials and methods: Static Intensity Modulated Radiation Therapy (S-IMRT) using a 9-field and Volumetric Modulated Arc Therapy (VMAT) using 2 full-arcs were established with treatment planning system on Computed Tomography images of a human phantom. Random gas parameters were included in the Planning Target Volume(PTV) with a maximum change of 2.0 cm in increments of 0.5 cm. Then, the Conformity Index (CI), Homogeneity Index (HI) and PTV D_max for the target volume were calculated, and the minimum dose (D_min), mean dose (D_mean) and Maximum Dose (D_max) were calculated and compared for OAR(organs at risk). For statistical analysis, T-test was performed to obtain a p-value, where the significance level was set to 0.05. Result: The HI coefficients of determination(R²) of S-IMRT and VMAT were 0.9423 and 0.8223, respectively, indicating a relatively clear correlation, and PTV D_max was found to increase up to 2.8% as the volume of a given gas parameter increased. In case of OAR evaluation, the dose in the bladder did not change with gas volume while a significant dose difference of more than D_mean 700 cGy was confirmed in rectum using both treatment plans at gas volumes of 1.0 cm or more. In all values except for D_mean of bladder, p-value was less than 0.05, confirming a statistically significant difference. Conclusion: In the case of gas generation not considered in the reference treatment plan, as the amount of gas increased, the dose difference at PTV and the dose delivered to the rectum increased. Therefore, during radiation therapy, it is necessary to make efforts to minimize the dose transmission error caused by a large amount of gas volumes in the rectum. Further studies will be necessary to evaluate dose transmission by not only varying the gas volume but also where the gas was located in the treatment field.

• Journal of radiological science and technology
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• v.26 no.1
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• pp.39-44
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• 2003

The aim of this study is to evaluate a efficient w/v% barium suspension and w/v% sodium carboxy methyl cellulose (SCMC) for small bowel examination. Between november 2001 and june 2002, 370 patients were examined small bowel examination with oral administration of barium suspension mixed with SCMC. we classified into six groups including A(fine type 40% $BaSO_4$ mixed 0.5% SCMC and 600 ml 0.5% SCMC administration), B(fine type 30% $BaSO_4$ mixed 0.5% SCMC), C(fine type 20% $BaSO_4$ mixed 0.5% SCMC), D(fine type 25% $BaSO_4$ mixed 0.5% SCMC), E(D mixed coarse type 25% $BaSO_4$ mixed 0.5% SCMC), F(D mixed coarse type 25% $BaSO_4$ mixed 0.75% SCMC). We measured transparency rate of contrast media transit time, administration dose, viscosity and particle size. The transparency rate was higher then 80 kV and 90 kV in 100 kV in the same 20 mAs condition. Transit time was the fastest in A group(mean trans time 56 minutes) and the slowest in E group(mean 100 minutes), Administration dose was the smallest in A group(mean dose 541 ml and the most in E group(mean 1,100 ml), viscosity was the lowest in E(125.1 mpa/s) and the highest in A(375.5 mpa/s), and particle size was $1.0\;{\mu}m$ in A, B, C, and D group, $0.6\;{\mu}m,\;1.0\;{\mu}m,\;10.0\;{\mu}m$ in E, F group. In conclusion, we propose that the efficient condition for small examination is high voltage technique, high density $BaSO_4$, and 0.625% w/v SCMC.

• Journal of Environmental Science International
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• v.27 no.6
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• pp.411-423
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• 2018

To investigate the distribution characteristics of grain size and organic matter of surface sediments from the Nakdong-Goryeong Mid-watershed, surface sediments were collected and analyzed. The samples were collected from six sited at four different times between May 2013 and May 2014. The were analyzed for grain size, water content, ignition loss, chemical oxygen demand, total organic carbon and total nitrogen. The surface sediments were mainly composed of medium sand (mean 44.7%) and coarse sand (mean 32.8%) and became coarser in May 2014. Fine sediments at the site NG-2 were poorly sorted and positively skewed, and occur in a tributary environment that is relatively low-energy compared with the other sites. The water content at the studied sites (15.3 ~ 34.9%) averaged 20.25%, and ignition loss (0.4 ~ 5.8%) and total nitrogen (274 ~ 2493 mg/kg) averaged 1.33% and, 696 mg/kg, respectively. These values indicated that the sediments were not seriously contaminated when compared with the sediment pollution evaluation standard of the National Institute of Environmental Research. The chemical oxygen demand (mean 0.17%) was at the non-polluted level compared with United States Environmental Protection Agency sediment quality standards. The total organic carbon (mean 0.18%) at all sites except site NG-2 (lowest effect level) was the no effect level of the Ontario sediment quality guidelines. The COD/IL (0.02 ~ 0.20) and C/N (0.73 ~ 6.76) were less than 1 and 10, respectively. Organic matter in the study area produced naturally from aquatic organisms. Results of principal component analysis showed that fine sediments (very fine sand and silt) were significantly affected by organic matters (ignition loss, chemical oxygen demand, total organic carbon and total nitrogen). In addition, the highest organic matters content in the study area occurred at the site with the finest sediments (NG-2).

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.1
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• pp.41-48
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• 2015

Juvenile banded catfish(Pseudobagurus fulvidraco, mean length $10.4{\pm}0.37cm$ and mean weight $14.5{\pm}0.46g$) were exposed to several nitrite(${NO_2}^-$) concentrations for 96h at pH levels of $6.18{\pm}0.54$, $6.5{\pm}0.30$ and $7.07{\pm}0.22$. The result showed that cumulative mortalities of fish to ${NO_2}^-$ levels of 12.4, 19.8, 33.9 and 53.6 mg/L at pH levels of $6.18{\pm}0.54$ were 20, 25, 40 and 85%, respectively. At pH $6.5{\pm}0.54$, mortalities to ${NO_2}^-$ 22.4, 36.4, 45.3 and 63.2 mg/L were 25, 35, 50 and 100%, respectively. At pH $7.07{\pm}0.22$, mortalities to ${NO_2}^-$ 25.5, 45.7, 56.3 and 66.4 mg/L were 0, 55, 70 and 100%, respectively. The 96h-$LC_{50}$(median lethal concentration, $LC_{50}$) of fish to several ${NO_2}^-$ concentrations at pH levels of $6.18{\pm}0.54$, $6.5{\pm}0.30$ and $7.07{\pm}0.22$ were assessed in these experiments. 96h-$LC_{50}$ at pH levels of $6.18{\pm}0.54$, $6.5{\pm}0.30$ and $7.07{\pm}0.22$ were 32.68, 40.49 and 45.85 mg/L, respectively. It indicated that acute toxicity of ${NO_2}^-$ to juvenile banded catfish increased with low levels of pH and lengthening of exposure time to ${NO_2}^-$. In particular, smaller fish(mean weight $14.5{\pm}0.46g$) were more sensitive to ${NO_2}^-$ than larger fish(mean weight $81.7{\pm}1.42g$; not published). The 96h-$LC_{50}$ of juvenile banded catfish to ${NO_2}^-$ would be primary guideline for water quality management in the intensive culture system such as RAS and BFT.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.3
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• pp.355-369
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• 2015

To examine species composition, abundance and biomass of fishes in the northwestern East Sea of Russian EEZ, trawl survey were conducted at 31 sampling stations from 2006 to 2008. Also, trawl survey were conducted at 21 sampling stations in the southwestern East Sea of Korean EEZ from 2006 to 2008. A total of 67 fishes were collected in the northwestern East Sea of Russian EEZ, a total of 39 fishes were collected in the southwestern East Sea of Korean EEZ. Among them, a total of 53 fishes were collected in the northwestern East Sea of Russian EEZ only, and a total of 25 fishes were collected in the southwestern East Sea of Korean EEZ only. Mean abundance per area which caught by trawl survey in the northwestern East Sea ranged from a high of $116,478inds./km^2$ in 2008 to a low of $19,737inds./km^2$ in 2006. And mean abundance per area in the southwestern East Sea ranged from a high of $89,129inds./km^2$ in 2006 to a low of $8,234inds./km^2$ in 2008. Mean biomass per area which caught by trawl survey in the northwestern East Sea ranged from a high of $11,333kg/km^2$ in 2008 to a low of $2,439kg/km^2$ in 2006. And mean biomass per area in the southwestern East Sea ranged from a high of $6,273kg/km^2$ in 2006 to a low of $1,062 kg/km^2$ in 2008. Cluster analysis, based on a Bray-Curtis similarity matrix of fourth root transformed data of number of species and individuals per area, showed division into three different groups by depth in the northwestern and southwestern East Sea.