• 제목/요약/키워드: progressive failure

검색결과 416건 처리시간 0.025초

Aspergillus Laryngotracheobronchitis in a Child with Primary Immunodeficiency

  • Moon, Soo Young;Lee, Soyoung;Kim, You Sun;Park, June Dong;Choi, Yu Hyeon
    • Pediatric Infection and Vaccine
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    • 제27권3호
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    • pp.190-197
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    • 2020
  • 소아에서 후두기관지염이 진균에 의해 발생하는 경우는 매우 드물고 주로 선행 요인이 있는 환자에 보고된다. 또한, Aspergillus 감염에 의한 후두기관지염은 초기에 무증상이거나 가슴 X선 사진에서 특이점이 없는 경우가 많아 조기 진단이 어렵다. 저자는 피부증상과 비감염성 발열을 조절하기 위해 장기간 저용량 스테로이드를 사용했던 복용력이 있는 일차성 면역 결핍 질환이 의심되는 환자에서 점진적인 호흡 부전을 보였고 가막성 아르페르길루스증(Pseudomembranous aspergillosis)에 의한 후두기관지염으로 밝혀진 사례를 보고하여 Aspergillus 후두기관지염의 고위험 환자군에서 조기 진단을 통한 치료의 중요성을 알리고자 한다.

Effect of core shape on debonding failure of composite sandwich panels with foam-filled corrugated core

  • Malekinejadbahabadi, Hossein;Farrokhabadi, Amin;Rahimi, Gholam H;Nazerigivi, Amin
    • Steel and Composite Structures
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    • 제45권3호
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    • pp.467-482
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    • 2022
  • One of the major failure modes in composite sandwich structures is the separation between skins and core. In this study, the effect of employing foam filled composite corrugated core on the skin/core debonding (resistance to separation between skin and core) is investigated both experimentally and numerically. To this aim, triangular corrugated core specimens are manufactured and compared with reference specimens only made of PVC foam core in terms of skin/core debonding under bending loading. The corrugated composite laminates are fabricated using the hand layup method. Also, the Vacuumed Infusion Process (VIP) is employed to join the skins to the core with greater quality. Utilizing an End Notched Shear (ENS) fixture, three point bending tests are performed on the manufactured sandwich composite panels. The results reveal that the resistance to separation capacity and flexural stiffness of sandwich composite has been increased about 170% and 76%, respectively by using a triangular corrugated core. The Cohesive Zone Model (CZM) with appropriate cohesive law in ABAQUS finite element software is used to model the progressive face/core interfaces debonding the difference between experimental and numerical results in predicting the maximum born load before the skin/core separation is about 6 % in simple core specimens and 3% in triangular corrugated core specimens.

Simulation study on effects of loading rate on uniaxial compression failure of composite rock-coal layer

  • Chen, Shao J.;Yin, Da W.;Jiang, N.;Wang, F.;Guo, Wei J.
    • Geomechanics and Engineering
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    • 제17권4호
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    • pp.333-342
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    • 2019
  • Geological dynamic hazards during coal mining can be caused by the failure of a composite system consisting of roof rock and coal layers, subject to different loading rates due to different advancing velocities in the working face. In this paper, the uniaxial compression test simulations on the composite rock-coal layers were performed using $PFC^{2D}$ software and especially the effects of loading rate on the stress-strain behavior, strength characteristics and crack nucleation, propagation and coalescence in a composite layer were analyzed. In addition, considering the composite layer, the mechanisms for the advanced bore decompression in coal to prevent the geological dynamic hazards at a rapid advancing velocity of working face were explored. The uniaxial compressive strength and peak strain are found to increase with the increase of loading rate. After post-peak point, the stress-strain curve shows a steep stepped drop at a low loading rate, while the stress-strain curve exhibits a slowly progressive decrease at a high loading rate. The cracking mainly occurs within coal, and no apparent cracking is observed for rock. While at a high loading rate, the rock near the bedding plane is damaged by rapid crack propagation in coal. The cracking pattern is not a single shear zone, but exhibits as two simultaneously propagating shear zones in a "X" shape. Following this, the coal breaks into many pieces and the fragment size and number increase with loading rate. Whereas a low loading rate promotes the development of tensile crack, the failure pattern shows a V-shaped hybrid shear and tensile failure. The shear failure becomes dominant with an increasing loading rate. Meanwhile, with the increase of loading rate, the width of the main shear failure zone increases. Moreover, the advanced bore decompression changes the physical property and energy accumulation conditions of the composite layer, which increases the strain energy dissipation, and the occurrence possibility of geological dynamic hazards is reduced at a rapid advancing velocity of working face.

대량 객혈에 대한 기관지동맥 색전술 -치험 2례- (Bronchial Artery Embolization of Massive Hemoptysis -2 cases-)

  • 강경훈
    • Journal of Chest Surgery
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    • 제21권6호
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    • pp.1117-1123
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    • 1988
  • Prolapse of the aortic valve is the main cause of insufficiency of the aortic valve as a complication of ventricular septal defect. Aortic insufficiency gets worse by the progress of prolapse of aortic valve due to lack of support of the valve and the hemodynamic effect of blood flow through the ventricular septal defect. This produces typical clinical picture, that may be serious and threatening when it is untreated. Type and timing for the surgical treatment of the ventricular septal defect with aortic insufficiency is considered. Among 113 ventricular septal defect, 9 patients of ventricular septal defect with associated aortic insufficiency were experienced from June. 1983 to June 1988 at the Department of Thoracic and Cardiovascular Surgery, Chon-Buk University Hospital. Male was 6 patients and female was 3 patients. Ages were from 7 years to 24years. 5 patients were from 10 to 19 years age. 3 patients were below 10 years age. The ratio of pulmonary blood flow to systemic f low [Qp/Qs] was 1.53 and in pulmonary vascular resistance, normal or slight increase was 7 patients, moderate 1 patient, and severe 1 patient. Ventricular septal defect was subpulmonic in 5 patients and infracristal in 4 patients. Prolapse of right coronary cusp was 7 patients, right and non coronary cusp 1 patient and non coronary cusp 1 patient. Teflon patch closure of ventricular septal defect was undertaken in 3 patients and primary closure in 1 patient. Among the 4 patients of defect closure alone, one patient performed valve replacement 7 months later due to progressive regurgitation and cardiac failure and the result was good. The other 3 patients were good result. Closure of ventricular septal defect and aortic valvuloplasty performed in 4 patients. 2 patients of these required valve replacement for the sudden intractable cardiac failure and died due to low cardiac output. The cause of intractable cardiac failure was tearing of repaired valve at the fixed site. The other 2 patients were good result. Closure of ventricular septal defect and valve replacement performed in 1 patient with good result.

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Risk Factors of Treatment Failure in Diabetic Foot Ulcer Patients

  • Lee, Kyung Mook;Kim, Woon Hoe;Lee, Jang Hyun;Choi, Matthew Seung Suk
    • Archives of Plastic Surgery
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    • 제40권2호
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    • pp.123-128
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    • 2013
  • Background Some diabetic feet heal without complication, but others undergo amputation due to progressive wounds. This study investigates the risk factors for amputation of diabetic feet. Methods A total of 55 patients who visited our institution from 2008 to 2012 were included in the study. The patients with abnormal fasting blood sugar levels, lower leg vascularity, and poor nutrition were excluded from the study group, and the wound states were unified. The patients were categorized into a treatment success group (n=47) and a treatment failure group (n=8), and their hemoglobin A1C (HgA1C), C-reactive protein (CRP), white blood cell count (WBC), and serum creatinine levels were analyzed. Results The initial CRP, WBC, and serum creatinine levels in the treatment failure group were significantly higher than that of the treatment success group, and the initial HgA1C level was significantly higher in the treatment success group. The CRP and WBC levels of both groups changed significantly as time passed, but their serum creatinine levels did not. Conclusions The initial CRP, WBC, and serum creatinine levels were considered to be risk factors for amputation. Among them, the serum creatinine level was found to be the most important predictive risk factor. Because serum creatinine represents the renal function, thorough care is needed for the feet of diabetic patients with renal impairment.

급성 신부전을 동반한 성인 Henoch-Sch$\ddot{o}$nlein 자반증 1예 (A Case of Adult onset Henoch-Sch$\ddot{o}$nlein Purpura with Acute Renal Failure)

  • 김석민;장경애;정선영;박찬서;박종원;도준영;김용진;윤경우
    • Journal of Yeungnam Medical Science
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    • 제25권1호
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    • pp.58-63
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    • 2008
  • Henoch-Sch$\ddot{o}$nlein purpura (HSP) is a leukocytoclastic vasculitis of small vessels with deposition of IgA, commonly resulting in skin, joint, gastrointestinal, and kidney involvement. HSP is an uncommon disorder in adults and accounts for 0.6% to 2% of adult nephropathy. We report a case of HSP with acute renal failure successfully treated with corticosteroid. In this case, the patient presented with vasculitic purpuric rash on lower extremity, arthralgia in the wrist, abdominal pain, hematochezia, oliguria and azotemia. Abdominal CT showed wall thickening of the small and large bowels. Skin biopsy revealed leukocytoclastic vasculitis. Percutaneous renal biopsy showed no crescent formation, but mesangial IgA and $C_3$ deposits were observed by immunofluorescence. The patient was treated with corticosteroid (1mg/kg per day) and hemodialysis. After treatment, renal function improved and purpuric lesion, arthralgia and abdominal pain disappeared. Thus, when adults present with purpuric rash and rapidly progressive glomerulonephritis (RPGN), HSP should be a diagnostic consideration.

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메틸말론산혈증 환자에서 파미드로네이트 치료 1례 (Pamidronate therapy for a Patient with Methylmalonic acidemia)

  • 조수진;서고훈;김윤명;김구환;유한욱;이범희
    • 대한유전성대사질환학회지
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    • 제18권1호
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    • pp.13-17
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    • 2018
  • 메틸말론산혈증은 선천성 유기산대사질환 중 하나로 증상의 발현시기 및 임상 증상이 매우 다양하며, 장기간의 합병증으로 세뇨관 간질 신염과 만성 신기능 저하, 췌장염, 기저핵 손상, 지능저하가 발생 할 수 있다. 연구자들은 이러한 메틸말론산혈증의 세뇨관 간질신염을 동반한 활동저하 환자에서 파미드로네이트 치료를 통해 고칼슘혈증과 골다공증의 호전을 경험하였기에 보고하는 바이다.

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외부 수압을 받는 복합재 원통의 후좌굴 연구 (Postbuckling of Composite Cylinders under External Hydrostatic Pressure)

  • 손희진;최진호;조종래;조상래;권진희
    • 한국항공우주학회지
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    • 제35권3호
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    • pp.196-203
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    • 2007
  • 외부 수압을 받는 복합재 원통의 좌굴 후 거동과 파손을 유한요소법과 시험으로 연구하였다. 좌굴 후 점진적 파손해석을 위해서는 비선형 유한요소해석 프로그램인 ACOS를 사용하였다. 유한요소해석의 타당성 검증을 위해 5개의 복합재 원통 모델을 제작하여 수압 시험을 수행하였다. 또한 상용 유한요소해석 프로그램인 MSC/NASTRAN과 MSC/MARC를 이용한 해석을 병행하여 ACOS에 의한 결과와 비교하였다. 세 개의 프로그램 중 ACOS가 실험과 가장 가까운 좌굴압력을 예측하였고, 한 경우를 제외하면, 실험값과는 약 12~26% 정도의 차이를 보였다. 해석에서는 원주방향으로 네 개의 웨이브를 가지는 전체 좌굴이 나타나지만, 실제 시험에서는 원통의 기하학적 초기결함으로 인해 국부좌굴이 발생하여 최종파손으로 연결되었다.

Oral rehabilitation of Papillon-Lefèvre syndrome patients by dental implants: a systematic review

  • Atarbashi-Moghadam, Fazele;Atarbashi-Moghadam, Saede;Kazemifard, Setare;Sijanivandi, Soran;Namdari, Mahshid
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • 제46권4호
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    • pp.220-227
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    • 2020
  • Objectives: Papillon-Lefèvre syndrome (PLS) is a rare autosomal recessive disorder. These patients lose their teeth at a young age and are in need of prosthetic rehabilitation. The aim of this systematic review was to assess the success of dental implant placement in these patients. Materials and Methods: An electronic search was performed in PubMed Central, Scopus, and Web of Science using the keyword "Papillon-Lefèvre syndrome" AND "dental implant" OR "prosthodontics". Articles reporting implant placement in patients with PLS until July 2019 were included. Results: Assessment of the included 11 articles reporting 15 cases showed 136 implant placements in these patients. Implant failure occurred in 3 patients (20 implants). The peri-implantitis and failure rate was higher in the maxilla. Meta-analysis showed the probability of failure to be 7% (95% confidence interval [CI] 0%-31%) for maxillary implants and 2% (95% CI 0%-9%) for mandibular implants. The follow-up time ranged between 1 and 20 years. Healing after bone graft and implant placement in these patients was uneventful. Conclusion: Dental implants may be a viable treatment option for PLS patients. Implantation can help preserve alveolar bone if the patients' immunological and growing conditions are well-considered and proper oral hygiene and compliance with the maintenance program are continued.

만성 신부전으로 진행된 비만 연관 사구체병증 1례 (Obesity Related Glomerulopathy Progressed to Chronic Renal Failure)

  • 안정희;윤정림;문경철;구자욱
    • Childhood Kidney Diseases
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    • 제14권1호
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    • pp.94-99
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    • 2010
  • Obesity-related glomerulopathy (ORG)는 단백뇨를 보이는 비만아에서 신장 조직학적 소견상 사구체 비대, 국소 분절성 사구체 경화 소견이 관찰되고 기저막 비후, 국소 간질조직 증식, 중등도의 발 돌기 소실 등을 보이는 질환으로 정의된다. 특발성 국소분절 사구체경화증과 비교하여 신증후군이 적으며 콜레스테롤 상승이 적고, 병의 진행이 느리다는 점에서 차이가 있다고 알려져 있으며, 체중감소를 통해 신장 기능이 회복될 수 있다고 알려져 있다. 본 증례의 9세된 비만아는 임상증상과 신장 조직검사에서 ORG로 진단되어 치료하였으나, 지속적인 체중 증가와 단백뇨로 말기 신부전으로 진행하여 소아 ORG 환아에서는 드문 경과를 취하여 이를 보고하는 바이다.