• Imaging Science in Dentistry
• /
• v.52 no.2
• /
• pp.171-179
• /
• 2022

Purpose: The aim of this study was to assess the accuracy of cone-beam computed tomographic (CBCT) images obtained using different voxel sizes in measuring trabecular bone microstructure in comparison to micro-CT. Materials and Methods: Twelve human skull bones containing posterior-mandibular alveolar bone regions were analyzed. CBCT images were obtained at voxel sizes of 0.075mm(high: HI) and 0.2mm(standard: Std), while microCT imaging used voxel sizes of 0.06 mm (HI) and 0.12 mm (Std). Analyses were performed using CTAn software with the standardized automatic global threshold method. Intraclass correlation coefficients were used to evaluate the consistency and agreement of paired measurements for bone volume (BV), percent bone volume (BV/TV), bone surface (BS), trabecular thickness (TbTh), trabecular separation (TbSp), trabecular number (TbN), trabecular pattern factor(TbPf), and structure model index (SMI). Results: When compared to micro-CT, CBCT images had higher BV, BV/TV, and TbTh values, while micro-CT images had lower BS, TbSp, TbN, TbPf, and SMI values (P<0.05). The BV, BV/BT, TbTh, and TbSp variables were higher with Std voxels, whereas the BS, TbPf, and SMI variables were higher with HI voxels for both imaging methods. For each imaging modality and voxel size evaluated, BV, BS, and TbTh were significantly different(P<0.05). TbN, TbPf, and SMI showed statistically significant differences between imaging methods(P<0.05). The consistency and absolute agreement between micro-CT and CBCT were excellent for all variables. Conclusion: This study demonstrated the potential of high-resolution CBCT imaging for quantitative bone morphometry assessment.

• Journal of Trauma and Injury
• /
• v.36 no.3
• /
• pp.231-241
• /
• 2023

Purpose: Overtriage and undertriage rates are critical metrics in trauma, influenced by both trauma team activation (TTA) criteria and compliance with these criteria. Analysis of undertriaged patients at a level I trauma center revealed suboptimal compliance with existing criteria. This study assessed triage patterns after implementing compliance-focused process interventions. Methods: A physician-driven, free-text alert system was modified to a nonphysician, hospital dispatcher-guided system. The latter employed dropdown menus to maximize compliance with criteria. The preintervention period included patients who presented between May 12, 2020, and December 31, 2020. The postintervention period incorporated patients who presented from May 12, 2021, through December 31, 2021. We evaluated appropriate triage, overtriage, and undertriage using the Standardized Trauma Assessment Tool. Statistical analyses were conducted with an α level of 0.05. Results: The new system was associated with improved compliance with existing TTA criteria (from 70.3% to 79.3%, P=0.023) and decreased undertriage (from 6.0% to 3.2%, P=0.002) at the expense of increasing overtriage (from 46.6% to 57.4%, P<0.001), ultimately decreasing the appropriate triage rate (from 78.4% to 74.6%, P=0.007). Conclusions: This study assessed a workflow change designed to improve compliance with TTA criteria. Improved compliance decreased undertriage to below the target threshold of 5%, albeit at the expense of increased overtriage. The decrease in appropriate triage despite compliance improvements suggests that the current criteria at this institution are not adequately tailored to optimally balance the minimization of undertriage and overtriage. This finding underscores the importance of improved compliance in evaluating the efficacy of TTA criteria.

• Korean Journal of Environmental Biology
• /
• v.18 no.1
• /
• pp.1-20
• /
• 2000

There are increasing evidences of climate change in the Antarctic and Arctic Oceans, especially elevated temperature due to the continuous burning of the fossil fuels and ultraviolet B(UV-B) flux within the ozone hole. Light-dependent, temperature-sensitive, and fast-growing organisms respond to these physical and biogeochemical changes. Polar marine phytoplankton, which are pioneer endemic species and important carbon contributors in the polar waters, are therefore highly suitable biological indicators of such changes. By virtue of light requirement, the primary producers are exposed to extreme seasonal fluctuations in temperature, photosynthetically active radiation, and UV radiation. Local environmental warming and increased UV-B radiation during ozone depletion may have profound effects on the primary producers that are primary carbon producers in the polar water. Small changes in climate temperature and solar radiation may have profound effects on the activity threshold of the polar phytoplanktion. To demonstrate biological response to the environmental changes, standardized representative natural and biological parameters are needed so that replicate samples (including controls) can be taken over extended periods of time. In this paper, we review general characteristics of polar phytoplankton, their environment, environmental changes in the polar waters, the effects on the environmental changes to the polar phytoplankton, and the importance of the polar phytoplankton to understand the global environmental changes. [Biological indicators, Global environmental change, Polar phytoplankton, UV].

• Radiation Oncology Journal
• /
• v.29 no.4
• /
• pp.243-251
• /
• 2011

Purpose: To evaluate the prognostic value of metabolic tumor volume (MTV) and maximum standardized uptake value (SUVmax) on initial positron emission tomography-computed tomography (PET-CT) and investigate the clinical value of SUVmax for early detection of locoregional recurrent disease after postoperative radiotherapy in patients with locally advanced head and neck squamous cell carcinoma (HNSCC). Materials and Methods: A total of 100 patients with locally advanced HNSCC received primary tumor excision and neck dissection followed by adjuvant radiotherapy with or without chemotherapy. The MTV and SUVmax were measured from primary sites and neck nodes. The prognostic value of MTV and SUVmax were assessed using initial staging PET/CT (study A). Follow-up PET/CT scan available after postoperative concurrent chemoradiotherapy or radiotherapy were evaluated for the SUVmax value and correlated with locoregional recurrence (study B). A receiver operating characteristic (ROC) curve analysis was used to define a threshold value of SUVmax with the highest accuracy for recurrent disease assessment. Results: High MTV (>41 mL) is negative prognostic factor for disease free survival (p = 0.041). Postradiation SUVmax was significantly correlated with locoregional recurrence (hazard ratio, 1.812; 95% confidence interval, 1.361 to 2.413; P < 0.001). A cutoff value of 5.38 from follow-up PET/CT was identified as having maximal accuracy for detecting locoregional recurrence by ROC analysis. Conclusion: MTV at staging work-up was significantly associated with disease free survival. The SUVmax value from follow-up PET/CT showed high diagnostic accuracy for the detection of locoregional recurrence in postoperatively irradiated HNSCC.

• Phonetics and Speech Sciences
• /
• v.6 no.2
• /
• pp.73-79
• /
• 2014

Alveolar fricative sounds /s/ and /s'/ are learned last for normal children in the speech development process for Koreans. These are especially difficult to articulate for hearing-impaired children often causing articulation errors. The acoustic phonetic evaluation uses testing tools to provide indirect and object information. These objective resources can be compared with standardized resources on speech when interpreting the results of a test. However, most previous studies in Korea did not consider acoustic studies that used the spectrum moment values of hearing-impaired children. Therefore, this study was conducted to compare the characteristics of hearing-impaired children's pronunciation of fricative sounds using spectrum moment values. For this purpose, the study selected a total of 10 hearing-impaired children (5 boys and 5 girls) currently in 3rd or 5th grade and attending one of the elementary schools in Seoul or Gyeonggi-do. For the selection process, their age, type of hearing aid, implantation of hearing aid (CI) before two years of age, hearing capacity (dB) before and after wearing the hearing aid, duration of speech rehabilitation, and time of learning alveolar fricative sounds were all considered. Also, 10 normal children (5 boys and 5 girls) were selected among 3rd or 5th grade students attending one of the elementary schools in Seoul or Gyeonggi-do. The subjects were asked to read the carrier sentence, "I say _______," including a list of 12 meaningless syllables composed of CV and VCV syllables, including alveolar fricative sounds /s/ and /s'/ and vowels /a/, /i/, and /u/. The recorded resources were processed through the Time-frequency Analysis Software Program to measure M1 (mean), M2 (variance), M3 (skewness), and M4 (kurtosis) of the fricative noise. No significant differences were found when comparing spectrum threshold values in the acoustic phonetic characteristics of hearing-impaired children and normal children in alveolar fricative sound pronunciation according to vowels /a/, /i/, and /u/, alveolar fricative sounds /s/ and /s'/, and syllable structure (CV, VCV) other than, for M3 in the comparison of groups according to disability. In the comparison of syllable structures, there were statistically significant differences in M1, M2, M3, and M4 with clinical significance. However, there was no significant difference in results when comparing the alveolar fricative sounds according to the vowels.

• Korean Journal of Food Science and Technology
• /
• v.42 no.2
• /
• pp.136-141
• /
• 2010

This study attempted to determine whether Photostimulated Luminescence (PSL) is applicable for the detection of post-irradiated foods by measuring the PSL photon counts of unirradiated and irradiated dried spices and herbs. A total of 19 dried spices and herbs was irradiated with a $^{60}Co$ $\gamma$-ray source at 1, 5 and 10 kGy followed by measurement of PSL photon. The photon counts of unirradiated samples below 700 correspond to negative. Fifteen samples irradiated over 1 kGy showed photon counts of more than 5,000, indicating irradiation treatment. Intermediate counts (photon count 700-5,000) were observed in irradiated white/black pepper, nutmeg and cinnamon bark at 10 kGy. These results suggest that it is possible to detect whether dried spices and herbs were irradiated by analyzing PSL, with the exception of white/black pepper, nutmeg and cinnamon bark. Irradiated white/black pepper, nutmeg and cinnamon bark containing low levels of minerals were not sensitive to PSL. Therefore, further investigation is sugguested to be performed by Thermoluminescence (TL) analysis or another validated or standardized method.

• Journal of Korea Society of Industrial Information Systems
• /
• v.27 no.6
• /
• pp.41-49
• /
• 2022

The Internet Engineering Task Force (IETF) has standardized RPL (IPv6 Routing Protocol for Low-power Lossy Network) as a routing protocol for Low Power and Lossy Networks (LLNs), a low power loss network environment. RPL creates a route through an Objective Function (OF) suitable for the service required by LLNs and builds a Destination Oriented Directed Acyclic Graph (DODAG). Existing studies check the residual energy of each node and select a parent with the highest residual energy to build a DODAG, but the energy exhaustion of the parent can not avoid the network disconnection of the children nodes. Therefore, this paper proposes EC-RPL (Enhanced Connectivity-RPL), in which ta node leaves DODAG in advance when the remaining energy of the node falls below the specified energy threshold. The proposed protocol is implemented in Contiki, an open-source IoT operating system, and its performance is evaluated in Cooja simulator, and the number of control messages is compared using Foren6. Experimental results show that EC-RPL has 6.9% lower latency and 5.8% fewer control messages than the existing RPL, and the packet delivery rate is 1.7% higher.

• Korean Journal of Radiology
• /
• v.23 no.12
• /
• pp.1260-1268
• /
• 2022

Objective: To propose standardized MRI-proton density fat fraction (PDFF) cutoff values for diagnosing hepatic steatosis, evaluated using contemporary PDFF measuring methods in a large population of healthy adults, using histologic fat fraction (HFF) as the reference standard. Materials and Methods: A retrospective search of electronic medical records between 2015 and 2018 identified 1063 adult donor candidates for liver transplantation who had undergone liver MRI and liver biopsy within a 7-day interval. Patients with a history of liver disease or significant alcohol consumption were excluded. Chemical shift imaging-based MRI (CS-MRI) PDFF and high-speed T2-corrected multi-echo MR spectroscopy (HISTO-MRS) PDFF data were obtained. By temporal splitting, the total population was divided into development and validation sets. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance of the MRI-PDFF method. Two cutoff values with sensitivity > 90% and specificity > 90% were selected to rule-out and rule-in, respectively, hepatic steatosis with reference to HFF ≥ 5% in the development set. The diagnostic performance was assessed using the validation set. Results: Of 921 final participants (624 male; mean age ± standard deviation, 31.5 ± 9.0 years), the development and validation sets comprised 497 and 424 patients, respectively. In the development set, the areas under the ROC curve for diagnosing hepatic steatosis were 0.920 for CS-MRI-PDFF and 0.915 for HISTO-MRS-PDFF. For ruling-out hepatic steatosis, the CS-MRI-PDFF cutoff was 2.3% (sensitivity, 92.4%; specificity, 63.0%) and the HISTO-MRI-PDFF cutoff was 2.6% (sensitivity, 88.8%; specificity, 70.1%). For ruling-in hepatic steatosis, the CS-MRI-PDFF cutoff was 3.5% (sensitivity, 73.5%; specificity, 88.6%) and the HISTO-MRI-PDFF cutoff was 4.0% (sensitivity, 74.7%; specificity, 90.6%). Conclusion: In a large population of healthy adults, our study suggests diagnostic thresholds for ruling-out and ruling-in hepatic steatosis defined as HFF ≥ 5% by contemporary PDFF measurement methods.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.11
• /
• pp.7978-7989
• /
• 2015

Dyslipidemia is a major risk factor for cardio-cerebrovascular disease. Although the prevalence among Korean adults is very high, its management is known to be poor. The aim of this study was to access the prevalence, awareness, treatment, and control rates of dyslipidemia according to treatment guideline rather than diagnostic criteria. The risk factors for cardio-cerebrovascular disease were evaluated to apply the appropriate risk-based threshold of the lipid treatment targets according to risk category. Analysis was done using nationally representative data (n = 16,263) collected from adults aged 20 years and older participating the Korea National Health and Nutrition Examination Survey (KNHANS) 2010-2012. The age-standardized prevalence rate of dyslipidemia according to treatment criteria was 34.1%. Of these prevalent cases, however, only 19.2% were aware; 9.5% treated; and 8.7% controlled. The age-standardized control rate among treated persons was 47.5%. Men had a significantly higher prevalence than women (39.7% vs. 28.8%), but a significantly lower rate of awareness, treatment, and control (16.0% vs. 22.3%, 7.7% vs. 11.3%, and 6.1% vs. 11.2%, respectively). As the higher risk category, the prevalence rate was higher but the control rate was lower. The prevalence of patients with diabetes was 82.5% when applying the treatment criteria (LDL-cholesterol level of ${\geq}100mg/dL$ and triglyceride level of ${\geq}200mg/dL$). However, only 11.9 % of these were controlled, whose LDL-cholesterol and triglycerides were lower than the treatment goals. Our findings suggest that effective strategies are required to decrease the gap between the prevalence of dyslipidemia and the following treatment. It would be worthwhile to strengthen the follow-up management of patients with dyslipidemia in the National Health Screening Program, especially in the high risk group of cardio-cerebrovascular disease.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.1
• /
• pp.625-636
• /
• 2017

Dyslipidemia, hypertension, and diabetes are well-established risk factors for cardio-cerebrovascular disease (CVD). Although the prevalence of dyslipidemia among Korean adults is very high, its management is known to be poor. The aim of this study was to assess the prevalence, awareness, treatment, and control rates of dyslipidemia among adults aged 30 years and older in Gangwon-do, Korea. Analysis included 58,121 adults (29,123 males and 28,998 females) participating in the 2013-2014 Korea National Health Screening Program (KNHSP). Dyslipidemia was defined according to the treatment criteria rather than the diagnostic criteria in Korea. Therefore, high-low-density lipoprotein cholesterol (LDL)-cholesterolemia was deemed present in individuals with LDL-cholesterol levels that exceeded the appropriate risk-based threshold. The age-standardized prevalence was highest in dyslipidemia (32.5%), followed by hypertension (25.1%), and diabetes (9.4%). The awareness rate was 76.7% for hypertension and 74.7% for diabetes, but only 10.6% for dyslipidemia. The lowest patient treatment was found for dyslipidemia (9.4%). The control rate among those undergoing treatment was highest for hypertension (75.8), followed by dyslipidemia (63.3%), and diabetes (43.9%). The higher CVD-risk categories showed lower control rates of hyper-LDL-cholesterolemia. The prevalence of dyslipidemia was higher than hypertension and diabetes, but awareness and treatment rates were lower. Our findings indicate there is a wide gap between the prevalence of dyslipidemia and subsequent treatment, which suggests that effective strategies are required to improve dyslipidemia management. It would be worthwhile to strengthen the follow-up management of patients with dyslipidemia in the KNHSP, especially for the high risk group of CVD.