• 대한치과기공학회지
• /
• 제30권1호
• /
• pp.97-107
• /
• 2008

Objectives; The purpose of the present study is to investigate the difference in levels of satisfaction between dental laboratory owners and employed dental technicians in the area of dental laboratory management. Methods; The samples of seventy-one dental laboratory owners and sixty-six employed dental technicians were selected in a blinded and random manner. Data was collected through self-administered questionnaires and analyzed using average values, the t-test and multiple regression. Results; 1) There was no significant difference in the average values of general satisfaction levels related to dental laboratory management between dental lab owners and employees. 2) The average values of satisfaction levels in 11 specific items scored 'above average' among dental lab owners and 'average' among employees. 3) The average values of satisfaction levels in 10 specific items except for 'trust and respect' showed a significant difference between dental lab owners and employees. 4) Important factors which influenced the satisfaction level of dental lab owners were 'trust and respect' and 'improvement of employee's benefits'. In the employees group, 'trust and respect', 'improvement of employee's benefits' and 'technical information support' were important factors. Conclusion; The present study revealed that dental laboratory owners and employees have some gaps between the viewpoints in dental laboratory management. This suggests the necessity to improve management in a transparent and economical way. However this study has some limitation in that the sample size was not massive enough.

• 대한치과의사협회지
• /
• 제53권11호
• /
• pp.804-816
• /
• 2015

PURPOSE: The aim of this study was to evaluate the influence of the oxide layer removal process in the Co-Cr-Mo (CCM) abutment after casting procedure on the prosthesis settlement and screw stability. MATERIALS AND METHODS: CCM abutments of four different interface conditions (CCM-M; machined, CCM-O; oxide layer formed, CCM-B; blasted, CCM-P; polished after blasted) and gold abutment (Gold-C; Cast with type III Gold alloy) were used. The initial settling values of abutments were evaluated according to the difference of implant-abutment length when the tightening torques were applied at 5 Ncm and 30 Ncm, and the settling values of abutments caused by loading were evaluated according to the difference of implant-abutment length before and after loading with 250 N, 100000 cycle. The loss ratios of removal torque for abutment screws were evaluated according to the difference in value of removal torques under 30 Ncm tightening torque applied before and after cyclic loading. RESULTS: The CCM-P and CCM-B group showed a higher initial settling value compared with the Gold-C group (P<.05), while the Gold-C group showed the highest settling values caused by loading (P<.05) and no significant differences were observed for between CCM groups (P>.05). The loss ratio of removal torque values for the CCM-B, CCM-P groups did not differ significantly from that of the Gold-C group (P>.05). CONCLUSION: Even though the oxide layer was removed by different methods, CCM abutment with internal conical connection structure showed lower abutment settling and similar screw loosening after cyclic loading compared with gold abutment.

• 대한방사선기술학회지:방사선기술과학
• /
• 제24권2호
• /
• pp.35-40
• /
• 2001

Performance of SPECT imaging systems which use a rotating gamma camera, are affected by characteristics of the detector-collimator assembly, the data acquisition method, and the filter used in imaging reconstruction. The purpose of this study Is to examine image qualifies of SPECT with different types of low energy collimators. The SPECT imaging system in this study is a digital gamma camera system GCA-901A(Toshiba) and a data processing unit Scintipac-700(Shimadzu). The four types of collimators compared are UHR(ultra high resolution), LEHR(low energy high resolution), LEGP(low energy general purpose), and I-123 PAR(Parallel), with 0.27, 0.66, 1.00, and 2.06 relative sensitivity, respectively. In this case of the same collimators, the spatial resolutions measured in the slice plane showed a slight difference in the FWHM values(mean values of UHR, LEHR, LEGP, and I-123 PAR were 11.3 mm, 13.6 mm, 15.8 mm, and 20.4 mm, respectively) between the center and the circumference of the field of view, in the radial direction, but a large difference in the tangential direction, with lower FWHM values(values of UHR, LEHR, LEGP, and I-123 PAR were 8.4 mm, 8.7 mm, 9.3 mm, and 10.8 mm at 12 cm from the center, respectively). In comparison of SPECT images with the four types of collimators, except for the I-123 PAR collimator, image qualities of UHR, LEHR, and LEGP collimators showed only a slight difference. From the point of for, it is expected that the LEGP collimator would be suitable for SPECT imaging with $^{99m}Tc$.

• The Journal of Advanced Prosthodontics
• /
• 제15권4호
• /
• pp.179-188
• /
• 2023

PURPOSE. This in vitro study aimed to evaluate the performance of digital intraoral scanners in a completely edentulous patient with angled and parallel implants. MATERIALS AND METHODS. A total of 6 implants were placed at angulations of 0°, 5°, 0°, 0°, 15°, and 0° in regions #36, #34, #32, #42, #44, and #46, respectively, in a completely edentulous mandibular polyurethane model. Then, the study model created by connecting a scan body on the implants was scanned using a model scanner, and a 3D reference model was obtained. Three different intraoral scanners were used for digital impressions (PS group, TR group, and CS group, n = 10 in each group). The distances and angles between the scan bodies in these measurement groups were measured. RESULTS. While the Primescan (PS) impression group had the highest accuracy with 38 ㎛, the values of 104 ㎛ and 171 ㎛ were obtained with Trios 4 IOSs (TR) and Carestream 3600 (CS), respectively (P = .001). The CS scanner constituted the impression group with the highest deviation in terms of accuracy. In terms of dimensional differences in the angle parameter, a statistically significant difference was revealed among the mean deviation angle values according to the scanners (P < .001). While the lowest angular deviation was obtained with the PS impression group with 0.185°, the values of 0.499° and 1.250° were obtained with TR and CS, respectively. No statistically significant difference was detected among the impression groups in terms of precision values (P > .05). CONCLUSION. A statistically significant difference was found among the three digital impression groups upon comparing the impression accuracy. Implant angulation affected the impression accuracy of the digital impression groups. The most accurate impressions in terms of both distance and angle deviation were obtained with the PS impression group.

• 한국의류학회지
• /
• 제26권6호
• /
• pp.853-864
• /
• 2002

The purpose of this study was to measure consumption values and to investigate the differences in the process of decision making when purchasing apparel products among groups divided by consumption values. A self-administered questionnaire was distributed to 550 subjects in their 20's and 30's from Sepember 29th to October 25th in 2001; 463 were used for the data analysis. The results of this study were as follows; Consumption values were classified into five factors: Practical/functional value, Social/conformitive value, Subjective/aesthetic value, Epistemic value and Conspicuous value. Subjects were classified into 4 groups based on consumption values: the Conspicuous, the Epistemic, the Social/conformitive and the Indifferent. There were significant differences among the four groups in selected motives in the problem recognition process. Significant differences were found among the groups in own taste & personality in the information search process. Significant difference were also found in the importance of design, color, price, coordination, fashion and self-image in the alternative evaluation process.

• 한국산업보건학회지
• /
• 제11권2호
• /
• pp.153-160
• /
• 2001

Objectives : The authors evaluated the effects on renal function of workers chronically exposed to low-level organic solvent mixtures. Methods : The authors measured the level of urine ${\beta}2$-microglobulin(${\beta}2$-MG) and microalbumin as biochemical markers of renal function and damage in 29 male workers exposed to organic solvents for more than five years and compared their results with those of 30 male office clerks as a reference group. Results : 1. The mean values of hemoglobin, hematocrit, SGOT, SGPT, ${\gamma}$-GTP were all within normal limits and there was no significant difference, except for hemoglobin(p<0.01), between exposed and reference group. 2. The values of BUN and serum creatinine were within reference limits and there was no significant difference between exposed and reference group. 3. The difference of mean values of urine microalbumin corrected by urine creatinine were statistically significant (p<0.01), but those of urine ${\beta}2$-MG was not. 4. There were no correlation of urine hippuric acids with BUN, serum creatinine, urine microalbumin and ${\beta}2$-MG. 5. There were no significant difference of BUN, serum creatinine, urine microalbumin and ${\beta}2$-MG upon work duration. Conclusions: It is assumed that chronic low-level organic solvent exposure in these workers shows early renal dysfunction, glomerular changes. The result corresponds to previous studies showing the relationship between hydrocarbon exposure and glomerulonephritis. For evaluation of impairment on kidney tubules, we need further study using more precise markers and long-term follow-up.

• 동아시아식생활학회지
• /
• 제20권2호
• /
• pp.272-278
• /
• 2010

Various quality attributes were determined in muffins prepared using purple-colored sweet potato flour. Height of control muffins was 5.8 cm lease clarify. Height decreased with increasing quantity of sweet potato powder. Muffin volume was not appreciably affected. Moisture of control muffins was 21.84. The moisture value decreased with increasing quantity of sweet potato powder. Scanning electron microscopy examination revealed thick cell wall and rough stoma in muffins prepared with purple-colored sweet potato powder. The amount of gluten decreased as the quantity of purple-colored sweet potato powder increased. Brightness L values significantly changed as the amount of powder increased, indicative of a progressively darker product. Red index a values decreased as the quantity of purple-colored sweet potato powder increased. Yellow index b values decreased significantly in the control group as powder quantity increased. Hardness increased with increasing addition of powder, but no significant difference was evident between 6% and 9% amended samples. There were also no significant differences in springing in samples containing 3% and 6% powder but 9% powder produced a significant difference. Cohesiveness did not differ in unamended samples and samples amended with 3% and 9% powder, however a significant difference was evident in samples prepared with 6% powder. Gumminess and chewiness increased as the quantity of purple-colored sweet potato powder increased. Color did not differ appreciably in sample prepared with 3% and 9% Sample prepared with 3% additives showed the highest What? Color score? Something else? Please clarify with 6.4. There was no significant difference of the flavor in samples prepared with 3% and 6% powder, or in taste among samples prepared 3%, 6%, and 9% powder. No significant differences in texture were evident in any sample Overall acceptability was highest (7.2) in samples prepared with 3% of purple-colored sweet potato.

• The Korean Journal of Pain
• /
• 제34권2호
• /
• pp.217-228
• /
• 2021

Background: The purpose of this study was to assess the effectiveness of transcutaneous electrical nerve stimulation (TENS) in chronic low back pain and neuropathic pain. Methods: Seventy-four patients aged 18-65 with chronic low back pain were included in the study. Baseline measurements were performed, and patients were randomized into three groups. The first group received burst TENS (bTENS), the second group conventional TENS (cTENS), and the third group placebo TENS (pTENS), all over 15 sessions. Patients' visual analogue scale (VAS) scores were evaluated before treatment (preT), immediately after treatment (postT), and in the third month after treatment (postT3). Douleur Neuropathique 4 Questions (DN4), the Modified Oswestry Low Back Pain Disability Questionnaire (MOS), the Beck Depression Inventory (BDI), and sympathetic skin response (SSR) values were also evaluated preT and postT3. Results: A statistically significant improvement was observed in mean VAS scores postT compared to preT in all three groups. Intergroup comparison revealed a significant difference between preT and postT values, that difference being assessed in favor of bTENS at multiple comparison analysis. Although significant improvement was determined in neuropathic pain DN4 scores measured at postT3 compared to preT in all groups, there was no significant difference between the groups. No statistically significant difference was also observed between the groups in terms of MOS, BDI, or SSR values at postT3 (P > 0.05). Conclusions: bTENS therapy in patients with low back pain is an effective and safe method that can be employed in short-term pain control.

• Communications for Statistical Applications and Methods
• /
• 제30권6호
• /
• pp.631-652
• /
• 2023

In the two-condition within-subject mediation design, pairs of variables such as mediator and outcome are observed under two treatment conditions. The main objective of the design is to investigate the indirect effects of the condition difference (sum) on the outcome difference (sum) through the mediator difference (sum) for comparison of two treatment conditions. The natural condition variables mean the original variables, while the rotated condition variables mean the difference and the sum of two natural variables. The outcome difference (sum) is expressed as a linear model regressed on two natural (rotated) mediators as a parallel two-mediator design in two condition approaches: the natural condition approach uses regressors as the natural condition variables, while the rotated condition approach uses regressors as the rotated condition variables. In each condition approach, the total indirect effect on the outcome difference (sum) can be expressed as the sum of two individual indirect effects: within- and cross-condition indirect effects. The total indirect effects on the outcome difference (sum) for both condition approaches are the same. The invariance of the total indirect effect makes it possible to analyze the nature of two pairs of individual indirect effects induced from the natural conditions and the rotated conditions. The two-condition within-subject design is extended to the addition of a between-subject moderator. Probing of the conditional indirect effects given the moderator values is implemented by plotting the bootstrap confidence intervals of indirect effects against the moderator values. The expected indirect effect with respect to the moderator is derived to provide the overall effect of moderator on the indirect effect. The model coefficients are estimated by the structural equation modeling approach and their statistical significance is tested using the bias-corrected bootstrap confidence intervals. All procedures are evaluated using function lavaan() of package {lavaan} in R.

• Journal of applied mathematics & informatics
• /
• 제38권1_2호
• /
• pp.1-12
• /
• 2020

In this paper, we solve the difference equation $x_{n+1}={\frac{x_nx_{n-2}}{ax_n-bx_{n-2}}}$, n = 0, 1, …, where a and b are positive real numbers and the initial values x_-2, x_-1 and x₀ are real numbers. We also find invariant sets and discuss the global behavior of the solutions of aforementioned equation.