Strain Rate Dependence of the Spall Strength of Steels

The data on the dynamic (spall) strength for more than 30 steels are reported. These data were interpreted in terms of the fracture mechanics. The experimental data are interpreted in terms of the energy-based spall theory which predicts the dependence of the spall strength on the strain rate in the spall plane. Even if most of the tested steels exhibit the agreement with this theory there are some exceptions. In order to explain this disagreement a modification of the theory mentioned above bas been suggested. The obtained model predicts the observed steel behaviour.L'étude mentionne les valeurs de la résistance dynamique (d'écaillage) pour plus que 30 aciers. Ces valeurs ont été interprétées sur les bases de la mécanique de la rupture. Les résultats des expériences sont interprétées par la théorie énergétique d'écaillage prédiquant la dépendance de la résistance d'écaillage et de la vitesse de déformation sur le plan d'écaillage. Malgré que la plupart des aciers examinés montrent l'accord avec cette théorie, il y a aussi des exceptions. Dans l'intention d'expliquer ces désaccords, une modification de la théorie mentionnée est proposée dans at ourage. Le modèle obtenu prédique avec succès le comportement des aciers examinés pendant l'écaillage

The Use of High Strain Rate Testing to the Study of Turbine Missile Impact

A study of the interaction of turbine blades with the steel plate has been conducted. Experiments simulating this event have been numerically simulated using DYNA 3D code. This mathematical modelling needs reliable constitutive relations describing the material behaviour. These constitutive equations have been suggested on the results of material testing by the Hopkinson Split Bar Technique. Their vahdity has been further tested using of the Taylor impact test. It has been found that the computed values of the projectile residual velocities well agree with the experimental data for different impact velocities and for the turbine fragments of different shapes.On étudie l'intéraction d'une aube de turbine avec une plaque d'acier. Les expériences effectuées ont été simulées par le code DYNA 3D. Cette simulation exige des relations constitutives fiables décrivant le comportement des matériaux. Ces équations constitutives ont été obtenues par la technique de la barre d'Hopkinson. La validité des résultats a été ensuite vérifiée par le test de Taylor. La valeur de la vitesse résiduelle calculée du projectile est en bon accord avec les données obtenues par l'expérience dans tout le domaine des vitesses d'incidence et pour des fragments d'aube de turbine de différentes formes

A case of type I Gaucher disease with cardiopulmonary amyloidosis and chitotriosidase deficiency

Severe cardiopulmonary amyloidosis developed several months after a total splenectomy in a patient with type 1 Gaucher disease and led within a year to his death at 48 years of age. The autopsy findings were dominated by extensive pulmonary and cardiac amyloid infiltration. No Gaucher cells were found in the lungs. Aside from a glucocerebrosidase deficiency the patient was also deficient in chitotriosidase, an enzyme whose activity is usually greatly increased in the serum of Gaucher patients. Analysis of mutations in the glucocerebrosidase gene revealed heterozygosity for N370S and D409H mutations. The normal amount of glucocerebrosidase was found in the spleen by Western blotting. We suggest that amyloidosis should be considered in the differential diagnosis of severe cardiopulmonary disease in Gaucher patient

Novel oral treatment of Gaucher's disease with N-butyldeoxynojirimycin (OGT 918) to decrease substrate biosynthesis.

BACKGROUND: Current treatment for Gaucher's disease involves administration of intravenous glucocerebrosidase to degrade glucocerebroside stored in lysosomes. Lowering the rate of biosynthesis of glucocerebroside should decrease accumulation of this substrate. We investigated the safety and efficacy of OGT 918 (N-butyldeoxynojirimycin), an inhibitor of glucosyltransferase, as a novel oral treatment for non-neuronopathic Gaucher's disease. METHODS: We recruited, into a 1-year open-label study, 28 adults (seven with previous splenectomies) from four national Gaucher's referral clinics, who were unable or unwilling to receive enzyme treatment. We measured liver and spleen volume by computed tomography or magnetic resonance imaging at baseline and at months 6 and 12, and biochemical and haematological variables monthly, including chitotriosidase activity (a sensitive marker of Gaucher's disease activity). Patients were started on 100 mg oral OGT 918 three times daily. FINDINGS: Baseline liver volumes were 1.1-2.7 times normal and spleen volumes 5.1-24.8 times normal. At 12 months, mean liver and spleen volumes were significantly lowered by 12% (95% CI 7.8-16.4) and 19% (14.3-23.7), respectively (each p<0.001). Haematological variables improved slightly. Mean organ volume and blood counts improved continually between 6 months and 12 months of treatment. Mean chitotriosidase concentrations fell by 16.4% over 12 months (p<.0001). Six patients withdrew because of gastrointestinal complaints (two), personal reasons (two), or severe pre-existing disease (two). The most frequent adverse effect was diarrhoea, which occurred in 79% of patients shortly after the start of treatment. INTERPRETATION: Decrease of substrate formation by OGT 918 improves key clinical features of non-neuronopathic Gaucher's disease. The strategy justifies further trials in this and other glycosphingolipid storage disorders