• Journal of Dental Anesthesia and Pain Medicine
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• 제19권1호
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• pp.37-44
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• 2019

Objective: Arthrocentesis is a minimally invasive surgical procedure that is used to alleviate the symptoms of temporomandibular joint (TMJ) disorders. The aim of this study was to investigate the effect of arthrocentesis on the blood supply to the retinal structures. Materials and Methods: Arthrocentesis was performed on 20 patients with TMJ disorders, and choroidal thickness (CT) in patients was measured to evaluate retinal blood circulation. The blood volume of the retinal structures was evaluated ipsilaterally before and after arthrocentesis, and these measurements were then compared with measurements obtained from the contralateral side. Results: Before arthrocentesis, there were no differences in retinal blood volumes between the ipsilateral and contralateral sides (P = 0.96). When ipsilateral CT measurements taken before and after arthrocentesis were compared, retinal blood supply was found to have significantly decreased after arthrocentesis (P = 0.04). When contralateral CT measurements taken before and after arthrocentesis were compared, retinal blood supply was also found to have decreased after arthrocentesis, but not significantly (P = 0.19). Conclusion: The solution of local anesthesia with epinephrine applied before the arthrocentesis procedure was found to reduce the blood volume of the retinal structures. To the best of our knowledge, this is the first study that has investigated the blood volume of the retinal structures following arthrocentesis.

• Wind and Structures
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• 제32권4호
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• pp.371-391
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• 2021

Tornadoes are the most devastating meteorological natural hazards. Many empirical and theoretical numerical models of tornado vortex have been proposed, because it is difficult to carry out direct measurements of tornado velocity components. However, most of existing numerical models fail to explain the physical structure of tornado vortices. The present paper proposes a new empirical numerical model for a tornado vortex, and its load effects on a low-rise and a tall building are calculated and compared with those for existing numerical models. The velocity components of the proposed model show clear variations with radius and height, showing good agreement with the results of field measurements, wind tunnel experiments and computational fluid dynamics. Normal stresses in the columns of a low-rise building obtained from the proposed model show intermediate values when compared with those obtained from existing numerical models. Local forces on a tall building show clear variation with height and the largest local forces show similar values to most existing numerical models. Local forces increase with increasing turbulence intensity and are found to depend mainly on reference velocity Uref and moving velocity Umov. However, they collapse to one curve for the same normalized velocity Uref / Umov. The effects of reference radius and reference height are found to be small. Resultant fluctuating force of generalized forces obtained from the modified Rankine model is considered to be larger than those obtained from the proposed model. Fluctuating force increases as the integral length scale increases for the modified Rankine model, while they remain almost constant regardless of the integral length scale for the proposed model.

• Asian-Australasian Journal of Animal Sciences
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• 제30권8호
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• pp.1074-1080
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• 2017

Objective: The growth, carcass and retail cut yield records on 1,428 Hanwoo steers obtained through progeny testing were analyzed in this study, and their heritability and genetic relationships among the traits were estimated using animal models. Methods: Two different models were compared in this study. Each model was fitted for different fixed class effects, date of slaughter for carcass traits and batch of progeny test live measurement traits, and a choice of covariates (carcass weight in Model 1 or backfat thickness in Model 2) for carcass traits. Results: The differences in body composition among individuals were deemed being unaffected by their age at slaughter, except for carcass weight and backfat thickness. Heritability estimates of body size measurements were 0.21 to 0.36. Heritability estimates of retail cut percentage were high (0.56 from Model 1 and 0.47 from Model 2). And the heritability estimates for loin muscle percentage were 0.36 from Model 1 and 0.42 from Model 2, which were high enough to consider direct selection on carcass cutability traits as effective. The genetic correlations between body size measurements and retail cut ratio (RCR) were close to zero. But, some negative genetic correlations were found with chest girths measured at yearling (Model 1) or at 24 months of age or with chest widths. Loin muscle ratio (LMR) was genetically negatively correlated with body weights or body size measurements, in general in Model 1. These relationships were low close to zero but positive in Model 2. Phenotypic correlation between cutability traits (RCR, LMR) and live body size measurements were moderate and negative in Model 1 while those in Model 2 were all close to zero. Conclusion: Therefore, the body weights or linear body measurements at an earlier age may not be the most desirable selection traits for exploitation of correlated responses to improve loin muscle or lean meat yield.

• Journal of Radiation Protection and Research
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• 제35권1호
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• pp.1-5
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• 2010

This study concerning the surface dose of eye and thyroid from panoramagraphy used thermoluminescent dosimeter (TLD) and photoluminescent dosimeter (PLD) to take measurements at ten hospitals in the Gwangju metropolitan area. The recommendations from ICRP 60 and ICRP 73 on the allowance standard for eye are 15 mSv and for thyroid is 1 mSv. The left eye TLD and PLD values are 0.19 mSv and 0.24 mSv respectively. The right eye TLD and PLD values are 0.23 mSv and 0.25 mSv respectively. Thyroid TLD and PLD values are 0.08 mSv and 0.25 mSv respectively and did not exceed the allowance standards(p<0.001). Also comparisons are made between TLD and PLD for each organ and PLD has higher dose measurements than TLD. There are statistically significant differences in left eye measurements and thyroid measurements (p<0.01). There is no significant difference in measurements for the right eye (p>0.05). The TLD and PLD measured dose from panoramagraphy instruments on eyes and thyroid from each hospital did not exceed the recommended dose from ICRP 60 for surface dose measurements. However, due to the probability of influence, consideration should be made for all levels of dose.

• Imaging Science in Dentistry
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• 제52권4호
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• pp.399-408
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• 2022

Purpose: The purpose of this study was to compare volume measurements obtained using 2 image software packages on Digital Imaging and Communications in Medicine (DICOM) images acquired from 1 multidetector computed tomography and 5 cone-beam computed tomography devices, using different protocols for physical volume measurements. Materials and Methods: Four pieces of bovine leg were prepared. Marrow was removed from 3 pieces, leaving cortical bone exposed. The resulting space of 1 piece was filled with water, another was filled with propylene glycol, and the third was left unfilled. The marrow in the fourth sample was left fully intact. Volume measurements were obtained after importing DICOM images into the Dolphin Imaging 11.95 and ITK-SNAP software programs. Data were analyzed using 3-way analysis of variance with a generalized linear model to determine the effects of voxel size, software, and content on percentage mean volume differences between tomographic protocols. A significance level of 0.05 was used. Results: The intraclass correlation coefficients for intraobserver and interobserver reliability were, respectively, 0.915 and 0.764 for the Dolphin software and 0.894 and 0.766 for the ITK-SNAP software. Three sources of statistically significant variation were identified: the interaction between software and content (P=0.001), the main effect of content (P=0.014), and the main effect of software (P=0.001). Voxel size was not associated with statistically significant differences in volume measurements. Conclusion: Both content and software influenced the accuracy of volume measurements, especially when the content had gray values similar to those of the adjacent tissues.

• 대한의용생체공학회:의공학회지
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• 제19권2호
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• pp.177-182
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• 1998

본 연구에서는 체내의 티타늄, 보철물, malalignment, 측정범위, 그리고 보철물 distal flare등이 전산화단층(CT) 촬영으로 골밀도를 축정할때에 미치는 영향을 조사하였다. 8구의 남성 사체로부터 대퇴골과 경골을 각각 8개씩 얻었으며 경골의 상부에 위치해있는 해면골 부분에서 15개의 평행사변형 시편을 만들었다. 평행사변형 시편과 대퇴골을 CT 스캔받침대의 중앙에 바로 놓았을때와 조금 떨어져 놓았을 때 그리고 티타늄 보철물을 체내에 넣었을 경우와 그렇지 않았을 경우 모두에 대해서 각각 스캔하였다. 이때 얻어진 CT 영상자료는 측정범위를 10cm와 30cm로 해서 재구성 하였다. 그리고 골밀도는 영상분석 소프트웨어을 사용하여 측정하였다. 그 결과 시편을 CT 스캔받침의 중앙에 놓았을 경우에는 그렇지 않았을 경우에 비해 골밀도 평균값의 상대차이가 피질골과 해면골 모두에 대해서 1% 미만이었다. 그러나 보철물의 malalignment와 distal flare는 골밀도의 측정값에 상당히 영향을 미쳤다. 체내에 티타늄 보철물의 존재여부는 시편을 CT 스캔받침대의 중앙에 놓았을 경우에는 피질골 뿐만 아니라 해면골 골밀도 측정값에 영향을 미치지 않았다. 그러나 체내에 티타늄 보철물의 존재가 malalignment 효과와 합쳐졌을때에는 골밀도 측정값이 많은 차이를 드러내었다.

• 대한치과교정학회지
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• 제33권2호
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• pp.73-84
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• 2003

본 연구는 정모두부방사선사진 촬영시 수직적 두부회전이 방사선사진상의 계측치들에 어느 정도의 투사오차를 야기 시키는지 알아보고자 시행되었다. 임상검사를 통하여 두드러진 전후방 골격이상이나 뚜렷한 안면비 대칭을 보이지 않는 성인 25명을 대상으로 natural head position상태를 기준위치$(0^{\circ})$로 정하고 이 위치에 대해 양쪽 ear rod를 연결한 수평축을 중심으로 두부를 상, 하방으로 $5^{\circ},\;10^{\circ}$씩 회전시킨 상태에서 정모두부방사선사진을 각각 촬영하여 투사도를 작성한 다음 7개의 고경항목, 5개의 폭경항목, 6개의 각도항목을 계측하였다. 각 회전각도에서의 계측치를 비교 분석하여 다음과 같은 결과를 얻었다. 1. 고경계측항목의 투사오차가 폭경이나 각도계측항목에 비해 전반적으로 큰 양상을 나타냈다. 2. 고경계측항목 중 회전축으로부터 먼 계측점간의 거리를 나타내는 항목일수록 투사오차가 컸다. 3. 폭경 계측항목 중 비강폭경, 상악폭경, 상악 제1대구치간 폭경은 각 회전각도 간에 통계적 유의차가 없었으나 하악폭 경과 하악 제1대구치간 폭경은 통지적으로 유의차가 있었다. 4. 각도계측항목 중 menton의 편위정도를 나타내는 각도는 각 회전각도 간에 통계적 유의차가 없었으나 crista galli와 maxillare를 연결한 선이나 crista galli와 antegonion을 연결한 선과 수평기준선이 이루는 각도는 통계적으로 유의차가 있었다. 이상의 결과는 수직적 두부회전에 의해 정모두부방사선사진상에 투사오차가 발생하므로 유용한 정모두부방사선사진을 얻기 위해서는 촬영시마다 동일한 두부위치를 유지하기 위한 노력이 필요함을 시사하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.101-110
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• 1997

The circuit effects due to the transformer primary side series equivalent inductance in the Zero Voltage Switching Pulse Width Modulated Half Bridge DC/DC Converter and its impact on the effective duty are analyzed. The steady state equations and the small signal model of the converter are derived incorporating the effects of the complementary control and the utilization of transformer primary side series equivalent inductance. The open plant dynamics are analyzed on the basis of the model derived. The model predictions are confirmed by experimental measurements.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2001년도 춘계학술대회
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• pp.311-317
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• 2001

The notched Charpy and Izod impact tests are the most prevalent techniques used to characterize the effects of high impulse loads on ploymeric materials. An analysis method for rubber toughened PVC is suggested to evaluate critical strain energy release rates(Gc) from the Charpy impact energy measurements. An Instrumented Charpy Impact tester was used to extract ancillary information concerning fracture properties in addition to total fracture properties and maximum critical loads. The stress intensity factor Kd was computed for varying amounts of rubber contents from the obtained maximum critical loads and also toughening effects were investigated as well.

• Wind and Structures
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• 제14권4호
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• pp.301-319
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• 2011

The full-scale measurements are compared with the wind tunnel test results for the long-span roof latticed spatial structure of Shenzhen Citizen Center. A direct comparison of model testing results to full-scale measurements is always desirable, not only in validating the experimental data and methods but also in providing better understanding of the physics such as Reynolds numbers and scale effects. Since the quantity and location of full-scale measurements points are different from those of the wind tunnel tests taps, the weighted proper orthogonal decomposition technique is applied to the wind pressure data obtained from the wind tunnel tests to generate a time history of wind load vector, then loads acted on all the internal nodes are obtained by interpolation technique. The nodal mean wind pressure coefficients, root-mean-square of wind pressure coefficients and wind pressure power spectrum are also calculated. The time and frequency domain characteristics of full-scale measurements wind load are analyzed based on filtered data-acquisitions. In the analysis, special attention is paid to the distributions of the mean wind pressure coefficients of center part of Shenzhen Citizen Center long-span roof spatial latticed structure. Furthermore, a brief discussion about difference between the wind pressure power spectrum from the wind tunnel experiments and that from the full-scale in-site measurements is compared. The result is important fundament of wind-induced dynamic response of long-span spatial latticed structures.