ABSTRACT
Casting of metallic glasses (MG) sometimes induces surface crystallisation despite the fact that the surface is expected to be the region where the cooling rate is the highest. This phenomenon has been observed on various MG, even for those with large critical diameters. Such surface crystallisation can be detrimental when the target applications are focused on surface properties, such as corrosion resistance for biomedical applications. In this paper, a Zr56Co28Al16 bulk metallic glass (BMG) with a large critical diameter was used. We reveal that samples processed using common copper-mould suction casting present surface crystallisation up to 20 µm in thickness, greatly deteriorating corrosion resistance. Using in-house highly reproducible suction casting and injection micro-casting processes, the influence of the processing parameters (mould material and temperature, working atmosphere, applied pressure) were investigated. The origin of surface crystallisation was found to arise from the complex thermal history of the alloy depending on the alloy/mould contact quality. By ensuring a tight contact between the solidifying alloy and the mould, BMG samples without crystalline surface defects were obtained.
ABSTRACT
Telomere length has been proposed as a marker of mitotic cell age and as a general index of human organism aging. Telomere shortening in peripheral blood lymphocytes has been linked to cardiovascular-related morbidity and mortality. The authors investigated the potential correlation of conventional risk factors, radiation dose and telomere shortening with the development of coronary artery disease (CAD) following radiation therapy in a large cohort of Hodgkin lymphoma (HL) patients. Multivariate analysis demonstrated that hypertension and telomere length were the only independent risk factors. This is the first study in a large cohort of patients that demonstrates significant telomere shortening in patients treated by radiation therapy who developed cardiovascular disease. Telomere length appears to be an independent prognostic factor that could help determine patients at high risk of developing CAD after exposure in order to implement early detection and prevention.
Subject(s)
Coronary Artery Disease/genetics , Coronary Artery Disease/mortality , Hodgkin Disease/radiotherapy , Radiometry/statistics & numerical data , Radiotherapy, Conformal/statistics & numerical data , Telomere Shortening/physiology , Adolescent , Adult , Aged , Biological Assay/methods , Biological Assay/statistics & numerical data , Causality , Child , Cohort Studies , Comorbidity , Female , Hodgkin Disease/mortality , Humans , Incidence , Male , Middle Aged , Prognosis , Radiometry/methods , Radiotherapy Dosage , Reproducibility of Results , Risk Assessment/methods , Sensitivity and Specificity , Survival Rate , Telomere Shortening/genetics , Young AdultABSTRACT
OBJECTIVE: To identify and analyse the risk factors for infective endocarditis. DESIGN: Retrospective survey over a 12-year period. SETTING: Department of Paediatric Cardiology, Nancy, France. SUBJECTS: 43 children attending during 1970-1992 who were diagnosed with infective endocarditis in accordance with Von Reyn's classification. RESULTS: 45 episodes of infective endocarditis were recorded (2 children had 2 episodes). Congenital cardiac disease was the most frequent predisposing factor for infective endocarditis. The causes of bacteraemia found were frequently, but not exclusively, of dental origin (30.5%). Among the dental causes were: poor oral health, inappropriate treatments and lack of antibiotic prophylaxis. CONCLUSIONS: Children diagnosed with a cardiac disorder should be examined by a dentist. Modern principles of antibiotic therapy and accepted dental procedures must be performed as soon as possible and parents informed of the current preventive recommendations.