• Title/Summary/Keyword: Mechanical Failure

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Re-establishment of occlusal plane in a patient with a failed implant prosthesis (실패한 임플란트 보철수복물을 가진 환자의 교합평면 재설정)

  • Kang, Hyeon-Goo;Ko, Kyung-Ho;Huh, Yoon-Hyuk;Cho, Lee-Ra;Park, Chan-Jin
    • The Journal of Korean Academy of Prosthodontics
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    • v.56 no.2
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    • pp.141-153
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    • 2018
  • A non-physiological occlusal plane caused by continuous tooth loss, occlusal wear, and failure of a prosthesis may result in an unattractive appearance and functional problems, such as reduced masticatory efficiency and occlusal interference. Therefore, when undertaking prosthetic treatment for edentulous patients or patients with a collapsed occlusal plane, it is important to establish an occlusal plane that is compatible with masticatory function. The patient in this case report had undergone restoration of a completely edentulous maxilla using an implant-supported fixed prosthesis. On follow-up examination in the following 6 years, mechanical complications were observed in the existing implant prosthesis, including porcelain chipping, occlusal wear, and screw loosening. Moreover, due to occlusal wear and supraeruption of the opposing anterior teeth, as well as loss of some posterior teeth, the occlusal plane had collapsed. Following diagnosis, the patient underwent full mouth rehabilitation, involving additional implant installation in edentulous sites, recreation of the existing prosthesis, and prosthetic restoration of all remaining teeth.

A Case of Cryoglobulinemia-induced Acute Respiratory Distress Syndrome (한냉글로불린혈증 환자에서 발생한 급성호흡곤란증후군 1예)

  • Kim, Byung-Gyu;Shim, Jae-Jeong;Jung, Ki-Hwan;Shin, Jeong-Ho;Lee, Seung-Heon;Kong, Hee-Sang;Kim, Je-Hyeong;Bak, Sang-Myeon;Shin, Chol;In, Kwang-Ho;Kang, Kyung-Ho;Yoo, Se-Hwa
    • Tuberculosis and Respiratory Diseases
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    • v.51 no.2
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    • pp.155-160
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    • 2001
  • Cryoglobulinemia is the presence of globulins in the serum that precipitate on exposure to cold temperatures(cryoglobulins). Pulmonary complications of cryoglobulinemia include interstial infiltration, impaired gas exchange, small airway disease and pleurisy. Only one other acute respiratory distress syndrome(ARDS) case has been described in patients with cryoglobulinemia. A 55-years old man was admitted with dyspnea. He had been diagnosed as being a hepatitis B virus antigen carrier 15 years ago. On the first admission, chest radiography showed a bilateral pleural effusion and a patchy infiltration on both lungs. On protein- and immuno-electrophoresis, cryoglobulinemia was confirmed. The patient was treated with corticosteroid and plasmapheresis. Forty-five days after the diagnosis, the patient complained of progressive dyspnea and showed a diffuse bilateral pulmonary infiltration on chest radiography. Despite intensive care with mechanical ventilation, the patient died as consequence of hypoxemia and multiple systemic organ failure. On a pathologic examination of the postmortem lung biopsy, multiple necrotizing vasculitis and increased infiltration of the lymphocytes and monocytes were observed. In conclusion, ARDS developed as a result of pulmonary hemorrhage due to cryoglobulinemia-associated vasculitis.

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Relationship and Clinical Usefulness between Preoperative Levels of Brain Natriuretic Peptide, Other Cardiac Markers and Perioperative Parameters in Patients with Coronary Artery Disease (관상동맥질환자에 있어 수술 전 brain natriuretic peptide 농도, 심장표지자, 수술전후기 변수들 간의 상관관계와 임상적 유용성)

  • Choi, Seok-Cheol;Kim, Yang-Weon;Hyun, Kyung-Yae;Hwang, Soo-Myung;Moon, Seong-Min
    • Journal of Life Science
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    • v.20 no.9
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    • pp.1299-1305
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    • 2010
  • Cardiac troponin-I (cTnI), creatine kinase-MB (CK-MB), and C-reactive protein (CRP) are routine cardiac markers for the diagnosis of cardiovascular disease. Recently, brain natriuretic peptide (BNP) has garnered attention as a marker of heart failure. This study was retrospectively designed to investigate the relationships between preoperative BNP, other cardiac markers levels and perioperative parameters in seventy-four adult patients that underwent off-pump coronary artery bypass grafting (OPCAB) and to assess its usefulness for predicting postoperative outcomes. Preoperative levels of BNP, cTnI, CK-MB, and CRP had significantly positive or negative correlations with echocadiographic parameters. There were significantly positive relationships between BNP, cTnI, CK-MB, and CRP concentration. Postoperative mechanical ventilation time had a positive correlation to preoperative levels of cTnI, CK-MB, and CRP, while ICU-staying period had a positive correlation with BNP, cTnI and CK-MB. These results reveal that a preoperative level of BNP is a good predictor and that its combination with cTnI, CK-MB, and CRP might be useful for diagnosis and comprehensive risk stratification of patients with coronary heart diseases, as well as prognosis of perioperative outcomes in OPCAB patients.

A Study on the Rollover Behavior of SUV and Collision Velocity Prediction using PC-Crash Program (PC-Crash를 이용한 SUV의 전복사고 거동 및 충돌속도 예측에 관한 연구)

  • Choi, Yong-Soon;Baek, Se-Ryong;Jung, Jong-Kil;Cho, Jeong-Kwon;Yoon, Jun-Kyu
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.18 no.2
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    • pp.227-235
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    • 2018
  • Along with the recent increase in traffic volume of vehicles, accidents involving rollover of vehicles have been rapidly increased, resulting in an increase casualties. And to prevent this, various technologies such as vehicle crash test equipment and analysis program development have been advanced. In this study, the applied vehicle model is FORD EXPLORER model, and PC-Crash program for vehicle collision analysis is used to predict the rollover accident behavior of SUV and the collision velocity. Compared with the actual rollover behavior of SUV through the FMVSS No 208 regulations, the analysis results showed similar results, the characteristics of the collision velocity and roll angle showed a tendency that the error rate slightly increased after 1000 msec. Then, as a result of considering using the database of NHTSA, it is shown that the rollover accident occur most frequently in the range of the collision velocity of 15~77 km/h and the collision angle of $22{\sim}74^{\circ}$. And it is possible to estimate the vehicle speed and collision time when the vehicle roof is broken by reconstructing the vehicle starting position, the roof failure position and the stop position by applying the actual accident case.

Videothoracoscopic Surgery for Secondary Spontaneous Pneumothorax (비디오 흉강경을 이용한 이차성 자연기흉의 치료)

  • 양현웅;정해동;최종범;최순호
    • Journal of Chest Surgery
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    • v.31 no.7
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    • pp.692-696
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    • 1998
  • For the management of a secondary spontaneous pneumothorax, videothoracoscopic surgery may offer the potential therapeutic benefits of a minimally invasive approach. We report on a series of 36 patients(33 men and 3 women) with a mean age of 56.3 years(range, 31 to 80 years) who underwent thoracoscopic surgical procedures for the treatment of secondary spontaneous pneumothorax. Twenty-one patients had emphysema and 20 patients had old pulmonary tuberculosis. Nineteen patients presented a persistent severe air leak more than 3 days preoperatively and 15 patients had more than one recurrence. Bullectomy or exclusion of the lesion was performed in 33 patients. Mechanical pleurodesis was performed in the entire patients, talc was sprayed in 22 and vibramycin in 14. Mild pleural adhesion at the upper lobe was shown in 10 patients and severe pleural adhesion in 7 patients. One patient with persistent air leak died of persistent air leak and respiratory failure. The mean postoperative stay was 7.0 days(range, 2 to 17 days). At a mean follow-up of 15.8 months (range, 5 to 45 months), no pneumothorax had recurred. In comparison with the result of the treatment for 112 patients with primary spontaneous pneumothorax, the operating time was not significantly longer and there were no more primary treatment failures, but the duration of postoperative chest drainage and hospital stay was longer. Videothoracoscopic surgery has proved to be an effective treatment for secondary spontaneous pneumothorax in elderly patients who represent high-risk candidates for thoracotomy.

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Experimental and Numerical Study on Board Level Impact Test of SnPb and SnAgCu BGA Assembly Packaging (BGA Type 유.무연 솔더의 기계적 충격에 대한 보드레벨 신뢰성 평가)

  • Lim, Ji-Yeon;Jang, Dong-Young;Ahn, Hyo-Sok
    • Journal of the Microelectronics and Packaging Society
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    • v.15 no.4
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    • pp.77-86
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    • 2008
  • The reliability of leaded and lead-free solders of BGA type packages on a printed circuit board was investigated by employing the standard drop test and 4-point bending test. Tested solder joints were examined by optical microscopy to identify associated failure mode. Three-dimensional finite element analysis(FEM) with ANSYS Workbench v.11 was carried out to understand the mechanical behavior of solder joints under the influence of bending or drop impact. The results of numerical analysis are in good agreement with those obtained by experiments. Packages in the center of the PCB experienced higher stress than those in the perimeter of the PCB. The solder joints located in the outermost comer of the package suffered from higher stress than those located in center region. In both drop and bending impact tests, the lead-free solder showed better performances than the leaded solders. The numerical analysis results indicated that stress and strain behavior of solder joint were dependent on various effective parameters.

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A novel PRF1 gene mutation in a fatal neonate case with type 2 familial hemophagocytic lymphohistiocytosis

  • Kim, Jae Yeon;Shin, Jeong Hee;Sung, Se In;Kim, Jin Kyu;Jung, Ji Mi;Ahn, So Yoon;Kim, Eun Sun;Seo, Ja-Young;Kang, Eun-Sook;Kim, Sun-Hee;Kim, Hee-Jin;Chang, Yun Sil;Park, Won Soon
    • Clinical and Experimental Pediatrics
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    • v.57 no.1
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    • pp.50-53
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    • 2014
  • Hemophagocytic lymphohistiocytosis (HLH) occurs in the primary form (genetic or familial) or secondary form (acquired). The familial form of HLH (FHL) is a potentially fatal autosomal recessive disorder that occurs because of constitutional defects in cell-mediated cytotoxicity. Here, we report a fatal neonatal case of type 2 FHL (FHL2) that involved a novel frameshift mutation. Clinically, the newborn presented with severe sepsis-like features and required mechanical ventilation and continuous venovenous hemodiafiltration. Flow cytometry analysis showed marked HLH and complete absence of intracytoplasmic perforin expression in cytotoxic cells; therefore, we performed molecular genetic analyses for PRF1 mutations, which showed that the patient had a compound heterozygous mutation in PRF1, that is, c.65delC ($p.Pro22Argfs^*2$) and c.1090_1091delCT ($p.Leu364Glufs^*93$). Clinical and genetic assessments for FHL are required for neonates with refractory fever and progressive multiple organ failure, particularly when there is no evidence of microbiological or metabolic cause.

The Evaluation of the atomic composition and the surface roughness of Titanium Implants following Various Laser treatment with air-powder abrasive (레이저 처리후 임프란트 표면 변화에 관한 연구)

  • Kim, Tae-Jung;Lim, Sung-Bin;Chung, Chin-Hyung
    • Journal of Periodontal and Implant Science
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    • v.32 no.3
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    • pp.615-630
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    • 2002
  • Various long-term studies have shown that titanium implants as abutments for different types of prostheses have become a predictable adjunct in the treatment of partially or fully edentulous patients. The continuous exposure of dental implants to the oral cavity with all its possible contaminants creates a problem. A lack of attachment, together with or caused by bacterial insult, may lead to peri-implantitis and eventual implant failure. Removal of plaque and calculus deposits from dental titanium implants with procedures and instruments originally made for cleaning natural teeth or roots may cause major alterations of the delicate titanium oxide layer. Therefore, the ultimate goal of a cleaning procedure should be to remove the contaminants and restore the elemental composition of the surface oxide without changing the surface topography and harming the surrounding tissues. Among many chemical and mechanical procedure, air-powder abrasive have been known to be most effective for cleaning and detoxification of implant surface. Most of published studies show that the dental laser may be useful in the treatment of pen-implantitis. $CO_2$ laser and Soft Diode laser were reported to kill bacteria of implant surface. The purpose of this study was to obtain clinical guide by application these laser to implant surface by means of Non-contact Surface profilometer and X-ray photoelectron spectroscopy(XPS) with respect to surface roughness and atomic composition. Experimental rough pure titanium cylinder models were fabricated. All of them was air-powder abraded for 1 minute and they were named control group. And then, the $CO_2$ laser treatment under dry, hydrogen peroxide and wet condition or the Soft Diode laser treatment under Toluidine blue O solution condition was performed on the each of the control models. The results were as follows: 1. Mean Surface roughness(Ra) of all experimental group was decreased than that of control group. But it wasn't statistically significant. 2. XPS analysis showed that in the all experimental group, titanium level were decreased, when compared with control group. 3. XPS analysis showed that the level of oxygen in the experimental group 1, 3($CO_2$ laser treatment under dry and wet condition) and 4(Soft Diode laser was used under toluidine blue O solution) were decreased, when compared with control group. 4. XPS analysis showed that the atomic composition of experimental group 2($CO_2$ laser treatment under hydrogen peroxide) was to be closest to that of control group than the other experimental group. From the result of this study, this may be concluded. Following air-powder abrasive treatment, the $CO_2$ laser in safe d-pulse mode and the Soft Diode laser used with photosensitizer would not change rough titanium surface roughness. Especially, $CO_2$ laser treatment under hydrogen peroxide gave the best results from elemental points of view, and can be used safely to treat peri-implantitis.

Evaluation of Interlayer Shear Properties and Bonding Strengths of a Stress-Absorbing Membrane Interlayer and Development of a Predictive Model for Fracture Energy (덧씌우기 응력흡수층에 대한 전단, 부착강도 평가 및 파괴에너지 예측모델 개발)

  • Kim, Dowan;Mun, Sungho;Kwon, Ohsun;Moon, Kihoon
    • International Journal of Highway Engineering
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    • v.20 no.1
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    • pp.87-95
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    • 2018
  • PURPOSES : A geo-grid pavement, e.g., a stress-absorbing membrane interlayer (SAMI), can be applied to an asphalt-overlay method on the existing surface-pavement layer for pavement maintenance related to reflection cracking. Reflection cracking can occur when a crack in the existing surface layer influences the overlay pavement. It can reduce the pavement life cycle and adversely affect traffic safety. Moreover, a failed overlay can reduce the economic value. In this regard, the objective of this study is to evaluate the bonding properties between the rigid pavement and a SAMI by using the direct shear test and the pull-off test. The predicted fractural energy functions with the shear stress were determined from a numerical analysis of the moving average method and the polynomial regression method. METHODS : In this research, the shear and pull-off tests were performed to evaluate the properties of mixtures constructed using no interlayer, a tack-coat, and SAMI with fabric and without fabric. The lower mixture parts (describing the existing pavement) were mixed using the 25-40-8 joint cement-concrete standard. The overlay layer was constructed especially using polymer-modified stone mastic asphalt (SMA) pavement. It was composed of an SMA aggregate gradation and applied as the modified agent. The sixth polynomial regression equation and the general moving average method were utilized to estimate the interlayer shear strength. These numerical analysis methods were also used to determine the predictive models for estimating the fracture energy. RESULTS : From the direct shear test and the pull-off test results, the mixture bonded using the tack-coat (applied as the interlayer between the overlay layer and the jointed cement concrete) had the strongest shear resistance and bonding strength. In contrast, the SAMI pavement without fiber has a strong need for fractural energy at failure. CONCLUSIONS : The effects of site-reflection cracking can be determined using the same tests on cored specimens. Further, an empirical-mechanical finite-element method (FEM) must be done to understand the appropriate SAMI application. In this regard, the FEM application analy pavement-design analysis using thesis and bonding property tests using cored specimens from public roads will be conducted in further research.

Study on 3D Printer Production of Auxiliary Device for Upper Limb for Medical Imaging Test (의료영상 검사를 위한 상지 보조기구의 3D 프린터 제작 연구)

  • Kim, Hyeong-Gyun;Yoon, Jae-Ho;Choi, Seong-Dae
    • Journal of radiological science and technology
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    • v.38 no.4
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    • pp.389-394
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    • 2015
  • There is a progressive development in the medical imaging technology, especially of descriptive capability for anatomical structure of human body thanks to advancement of information technology and medical devices. But however maintenance of correct posture is essential for the medical imaging checkup on the shoulder joint requiring rotation of the upper limb due to the complexity of human body. In the cases of MRI examination, long duration and fixed posture are critical, as failure to comply with them leads to minimal possibility of reproducibility only with the efforts of the examiner and will of the patient. Thus, this study aimed to develop an auxiliary device that enables rotation of the upper limb as well as fixing it at quantitative angles for medical imaging examination capable of providing diagnostic values. An auxiliary device has been developed based on the results of precedent studies, by designing a 3D model with the CATIA software, an engineering application, and producing it with the 3D printer. The printer is Objet350 Connex from Stratasys, and acrylonitrile- butadiene-styrene(ABS) is used as the material of the device. Dimensions are $120{\times}150{\times}190mm$, with the inner diameter of the handle being 125.9 mm. The auxiliary device has 4 components including the body (outside), handle (inside), fixture terminal and the connection part. The body and handle have the gap of 2.1 mm for smooth rotation, while the 360 degree of scales have been etched on the handle so that the angle required for observation may be recorded per patient for traceability and dual examination.