• The Journal of Advanced Prosthodontics
• /
• 제5권4호
• /
• pp.388-395
• /
• 2013

PURPOSE. The purpose of this study was to estimate the effects of occlusal stability to identify action mechanisms of mouthguards, known to have a modulatory effect on limb muscle function. MATERIALS AND METHODS. This study included 20 male subjects to perform the isokinetic muscle tests and the Wingate anaerobic power test on both knee joints under five closed-mouth conditions: without or with 4 types of mouthguards with thickness of 2 mm based on premolar area: (1) full-coverage, (2) anterior partial-coverage, (3) right posterior partial-coverage, and (4) left posterior partial-coverage. The obtained results were subjected to One-way ANOVA with repeated measures, followed by post hoc test of the contrast method (${\alpha}$=.05). RESULTS. There was no significant difference between the closed position with and without a full-coverage mouthguard in all variables. However, significant differences were observed between with and without a partial-coverage mouthguard in muscular endurance during extension of the left knee, muscular power and endurance during flexion of the right knee. Additionally, significant differences were found between occlusal states with full- and partial-coverage mouthguards in muscular power and endurance during extension of the left knee. CONCLUSION. These findings indicate the elevation of vertical dimension by 2 mm or the inducement of occlusal stability had little effect on isokinetic muscle strength and anaerobic performance, while uneven distribution of occlusal force might have some positive effects.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 춘계학술대회논문집
• /
• pp.647-652
• /
• 2008

This paper focused on the application of finite element model updating technique to evaluate the structural properties of the reinforced concrete specimen using the data collected from shaking table tests. The specimen was subjected to six El Centro(NS, 1942) ground motion histories with different Peak Ground Acceleration(PGA) ranging from 0.06g to 0.50g. For model updating, flexural stiffness values of structural members(walls and slabs) were chosen as the updating parameters so that the converged results have direct physical interpretations. Initial values for finite element model were determined from the member dimensions and material properties. Frequency response functions(i.e. transfer functions), natural frequencies and mode shapes were obtained using the acceleration measurement at each floor and given ground acceleration history. The weighting factors were used to account for the relative confidence in different types of inputs for updating(i.e. transfer function and natural frequencies). The constraints based on upper/lower bound of parameters and sensitivity-based constraints were implemented to the updating procedure in this study using standard bounded variable least-squares(BVLS) method. The veracity of the updated finite element model was investigated by comparing the predicted and measured responses. The results indicated that the updated model replicates the dynamic behavior of the specimens reasonably well. At each stage of shaking, severity of damage that results from cracking of the reinforced concrete member was quantified from the updated parameters(i.e. flexural stiffness values).

• 한국소음진동공학회논문집
• /
• 제18권7호
• /
• pp.725-731
• /
• 2008

This paper focused on the application of finite element model updating technique to evaluate the structural properties of the reinforced concrete specimen using the data collected from shaking table tests. The specimen was subjected to six El Centre (NS, 1942) ground motion histories with different peak ground acceleration (PGA) ranging from 0.06 g to 0.50 g. For model updating, flexural stiffness values of structural members (walls and slabs) were chosen as the updating parameters so that the converged results have direct physical interpretations. Initial values for finite element model were determined from the member dimensions and material properties. Frequency response functions (i.e. transfer functions), natural frequencies and mode shapes were obtained using the acceleration measurement at each floor and given ground acceleration history. The weighting factors were used to account for the relative confidence in different types of Inputs for updating (j.e. transfer function and natural frequencies) The constraints based on upper/lower bound of parameters and sensitivity-based constraints were implemented to the updating procedure in this study using standard bounded variable least-squares(BVLS) method. The veracity of the updated finite element model was investigated by comparing the predicted and measured responses. The results indicated that the updated model replicates the dynamic behavior of the specimens reasonably well. At each stage of shaking, severity of damage that results from cracking of the reinforced concrete member was quantified from the updated parameters (i.e. flexural stiffness values).

• Clinical and Experimental Pediatrics
• /
• 제60권11호
• /
• pp.337-343
• /
• 2017

Attention deficit hyperactivity disorder (ADHD) is one of the most common psychiatric disorders in childhood. This disorder, in addition to its main symptoms, creates significant difficulties in education, social performance, and personal relationships. Given the importance of rehabilitation for these patients to combat the above issues, the use of virtual reality (VR) technology is helpful. The aim of this study was to highlight the opportunities for VR in the rehabilitation of children with ADHD. This narrative review was conducted by searching for articles in scientific databases and e-Journals, using keywords including VR, children, and ADHD. Various studies have shown that VR capabilities in the rehabilitation of children with ADHD include providing flexibility in accordance with the patients' requirements; removing distractions and creating an effective and safe environment away from real-life dangers; saving time and money; increasing patients' incentives based on their interests; providing suitable tools to perform different behavioral tests and increase ecological validity; facilitating better understanding of individuals' cognitive deficits and improving them; helping therapists with accurate diagnosis, assessment, and rehabilitation; and improving working memory, executive function, and cognitive processes such as attention in these children. Rehabilitation of children with ADHD is based on behavior and physical patterns and is thus suitable for VR interventions. This technology, by simulating and providing a virtual environment for diagnosis, training, monitoring, assessment and treatment, is effective in providing optimal rehabilitation of children with ADHD.

• 폴리머
• /
• 제35권1호
• /
• pp.13-16
• /
• 2011

본 연구에서는 생체 적합성이 우수한 합성고분자 폴리비닐피롤리돈(PVP)과 천연고분자 카피-카라기난(${\kappa}C$), 1,2-헥산디올(HD)을 혼합하여 감마선 조사에 의한 방사선 가교로 하이드로젤을 제조하였다. 방사선 조사량은 25 kGy, ${\kappa}C$의 농도는 3 wt%로 고정하였다. 이렇게 제조된 하이드로젤의 의 PVP, HD의 농도에 따른 물리적 특성을 관찰하였다. PVP의 농도가 증가할수록 피롤리돈 분자 사이의 가교반응으로 젤화율과 연장강도는 증가하였고, 팽윤도는 감소하였다. 반면에 HD의 농도가 증가할수록 젤화율과 인장강도는 감소하였으며, 팽윤도는 증가하였다. 항균성 실험을 통해 HD를 함유한 하이드로젤에서 항곰팡이성 활성이 관찰되었다.

• 조명전기설비학회논문지
• /
• 제16권3호
• /
• pp.47-54
• /
• 2002

본 논문은 단상 50[kVA] 몰드변압기 권선부의 열전달 특성에 대한 연구 결과이다. 1차 권선의 열전도도는 권선을 이루고 있는 물질 비 즉, 1차 권선의 절연을 담당하는 다량의 에폭시 수지와 그에 비해 소량의 구리 도선을 고려하여 결정하였다. 반면에 2차 권선의 경우 구성 성분은 다량의 구리도선과 절연을 담당하는 소량의 에폭시 수지로 되어 있다. 2차 권선 열전도도는 질량 비로서 결정될 수 없기 때문에 2차 권선의 열전도도값은 시작품의 측정 최고온도와 FEM을 이용한 분석결과를 비교하여 결정하였다. 각 권선부의 물리적 특징을 고려하여 상용 프로그램을 통해 시뮬레이션 모델을 만들었다. 본 연구결과를 바탕으로 몰드변압기 권선부에 Hole이 존재할 때와 안할 때 각각에 대해 주위온도·풍속변화에 따른 최고온도 변화를 고찰하였다.

• Pediatric Infection and Vaccine
• /
• 제4권2호
• /
• pp.308-313
• /
• 1997

Ceftriaxone, an effective third generation cephalosporin with a wide range of antimicrobial activity, has become widely used by pediatricians for a variety of bacterial infections including meningitis. It has been associated with the development of sludge or stone in the gallbladder of some patients treated with this drug. Ceftriaxone associated biliary sludge has unusual acoustic characteristics and resembles gallstone. The sludge can cause symptoms such as cramping abdominal pain, and disappears after stopping ceftriaxone administration. Because of these seemingly confusing observations, it is important for the clinicians to recognize these findings that ceftriaxone treatment can cause. We report a case of ceftriaxone associated biliary sludge in Korean children. A 6-year-old girl who was treated for meningitis with ceftriaxone (100mg/kg/day) developed cramping upper abdominal pain from 5th hospital day. Physical examination, liver function tests and X-ray revealed no specific abnormal findings. But abdominal ultrasound revealed high amplitude echogenic sludge with prominent post-acoustic shadow in gallbladder and its diameter was 1.5cm. We stopped ceftriaxone administration and tried conservative care. Abdominal cramping pain subsided after 3 days of ceftriaxone removal. Second abdominal ultrasound confirmed the disappearance of sludge at 3 weeks later.

• Journal of Yeungnam Medical Science
• /
• 제7권1호
• /
• pp.121-126
• /
• 1990

전신마취를 필요로 하는 무증상 HBsAg양성 간효소치가 증가된 환자 11명을 대상으로 enflurane으로 마취한후 술전, 술후 3일, 7일 및 10일에 간기능검사를 실시하여 그 변화를 비교 검사한 결과 다음과 같은 결론을 얻었다. 1) SGOT, SGPT SGOT, SGPT는 술후 3일에는 술전수치보다 약간 증가하였으나 7일, 10일에는 현저한 증가를 보였다. 8예에 있어서는 술후 3일에 술전치 보다 약간 증가한 양상을 보였고 7일, 10일에 술전치와 비슷하게 되었으나 3예에서는 3일에 SGOT, SGPT가 약간 증가하더니 7일, 10일에는 SGOT, SGPT가 300-500IU로 상당히 증가하여 간염치료를 하여 술후 2개월후에 술전치와 비슷하게 하강하였다. 2) Alkaline phosphatase, total protein, albumin, total bilirubin, and direct bilirubin은 술후 3일에 정상범위를 벗어난 변화를 보였으며 7일부터 정상범위내로 회복되었다. 이상의 결과를 보아 enflurane마취가 간기능에 큰 영향을 미치지 않는다고는 하나 HBaAg양성 간효소치가 증가한 환자에게는 마취시 간염으로 이행될 가능성이 높으므로 상당히 조심을 하여 마취를 시행하여야 할 것으로 사료된다.

• 자동차안전학회지
• /
• 제10권4호
• /
• pp.25-32
• /
• 2018

Due to the rapid increase in the number of vehicles, the physical and human losses caused by traffic accidents have become serious social problems. In the global trend, there have been active studies conducted on improving safety level of automobile in order to reduce the number of automobile accident. As a result of such research, traffic accidents continue to decline. In the case of South Korea, however, rate of death by automobile accident is 8.5 per 10,000 people and it is a seven rank among the countries in OECD (Organization for Economic Cooperation and Development). This average rate is almost double compared to average automobile accident rate per 10,000 vehicles, of other OECD countries in 2015. Consequently, many studies and policies currently have been conducted and made for increasing safety of pedestrians; however, they are only emphasizing characteristics of pedestrians and drivers. For this reason, this study suggests scenarios for establishment of test standard corresponding with domestic environment and international standard of AEB (Autonomous Emergency Braking) and conducts a real car test by scenarios by setting up a goal with a function for remaining distance after braking and then examine equation by comparing real car tests results and outcome after calculation. This is a theoretical method to predict a relative remaining distance after AEB prior to conducting a real car test for evaluation of safeness of automobile with AEB and it is expected that it solves problem of complication of real car test.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• 제24권6호
• /
• pp.518-527
• /
• 2021

Purpose: The incidence of hepatic steatosis among children has been increasing; however, data distinguishing simple steatosis from a more complex disorder are lacking. Methods: This study identified the etiologies resulting in hepatic steatosis through a retrospective review of pediatric liver biopsies performed in the last 10 years. A total of 158 patients with hepatic steatosis proven by histopathological evaluation were enrolled in the study, and baseline demographic features, anthropometric measurements, physical examination findings, laboratory data, ultrasonographic findings, and liver histopathologies were noted. Results: The two most common diagnoses were inborn errors of metabolism (IEM) (52.5%) and nonalcoholic fatty liver disease/steatohepatitis (NAFLD/NASH) (29.7%). The three most common diseases in the IEM group were glycogen storage disorders, Wilson's disease, and mitochondrial disease. The rates of consanguineous marriage (75.6%; odds ratio [OR], 26.040) and positive family history (26.5%; OR, 8.115) were significantly higher (p=0.002, p<0.001, respectively) in the IEM group than those in the NAFLD/NASH group. Younger age (p=0.001), normal anthropometric measurements (p=0.03), increased aspartate aminotransferase levels (p<0.001), triglyceride levels (p=0.001), and cholestatic biochemical parameters with disrupted liver function tests, as well as severe liver destruction of hepatic architecture, cholestasis, fibrosis, and nodule formation, were also common in the IEM group. Conclusion: Parents with consanguinity and positive family history, together with clinical and biochemical findings, may provide a high index of suspicion for IEM to distinguish primary steatosis from the consequence of a more complex disorder.