Bending to Kinetic Energy Transfer in Adhesive Peel Front Microinstability.

We report an extensive experimental study of a detachment front dynamics instability, appearing at microscopic scales during the peeling of adhesive tapes. The amplitude of this instability scales with its period as A_{mss}∝T_{mss}^{1/3}, with a prefactor evolving slightly with the peel angle θ, and increasing systematically with the bending modulus B of the tape backing. Establishing a local energy budget of the detachment process during one period of this microinstability, our theoretical model shows that the elastic bending energy stored in the portion of tape to be peeled is converted into kinetic energy, providing a quantitative description of the experimental scaling law.

Experimental study of the effect of disorder on subcritical crack growth dynamics.

The growth dynamics of a single crack in a heterogeneous material under subcritical loading is an intermittent process, and many features of this dynamics have been shown to agree with simple models of thermally activated rupture. In order to better understand the role of material heterogeneities in this process, we study the subcritical propagation of a crack in a sheet of paper in the presence of a distribution of small defects such as holes. The experimental data obtained for two different distributions of holes are discussed in the light of models that predict the slowing down of crack growth when the disorder in the material is increased; however, in contradiction with these theoretical predictions, the experiments result in longer lasting cracks in a more ordered scenario. We argue that this effect is specific to subcritical crack dynamics and that the weakest zones between holes at close distance to each other are responsible for both the acceleration of the crack dynamics and the slightly different roughness of the crack path.

Experimental evidence of a phase transition in a closed turbulent flow.

We experimentally study the susceptibility to symmetry breaking of a closed turbulent von Kármán swirling flow from Re=150 to Re≃106. We report a divergence of this susceptibility at an intermediate Reynolds number Re=Re(χ)≃90,000 which gives experimental evidence that such a highly space and time fluctuating system can undergo a "phase transition." This transition is furthermore associated with a peak in the amplitude of fluctuations of the instantaneous flow symmetry corresponding to intermittencies between spontaneously symmetry breaking metastable states.

[Calcific constrictive pericarditis of anginal form complicated by hemopericardium and tamponade during anticoagulant treatment]. / Péricardite constrictive calcifiante à forme angineuse compliquée d'hémopéricarde et de tamponnade au décours d'un traitement anticoagulant

The case-history of a patient with calcified constrictive epicardopericarditis with rapidely progressive aggravation after digestive hemorrage due to excessive dose or oral anticoagulant therapy is reported. The occurrence of a cardiac tamponade has necessitated pericardectomy which has permitted to detect a partitionned hemopericardium. The surgical act was followed by gross improvement of both constrictive phenomenon and angina pectoris which have grounded the prescription of anticoagulant therapy. Anticoagulant therapy is likely responsible of the hemopericardium. Such facts are exceptionals in the course of constrictive pericarditis; diagnostic and therapeutic problems related to this complication are studied. The question of angina pectoris in the course of acute and chronic pericarditis is briefly studied by the way of this observation. Attention is drawed on the danger of the prescription of anticoagulant therapy in the course of some constrictive pericarditides.

[Isolated infiltrated cutaneous nodule revealing acute leukaemia (author's transl)]. / Tumeur cutanée unique révélatrice d'une leucémie aiguë de l'adulte. 2 observations.

The authors report on two cases of acute leukemia beginning with an isolated cutaneous lesion. The first case was a form of acute monoblastic leukosis which showed a favourable development following chemotherapeutic treatment, and was still in a state of remission two years later. The second case was a variety of acute monoblastic leukosis which, at the end of eighteen months' chemotherapeutic treatment, led to an unfavourable prognosis. Most interesting by, these reports highlight the mis-leading varieties of acute leukemia with an isolated cutaneous tumour. To make both accurate diagnosis and appropriate treatment possible, it is necessary to complement clinical and histological examination with hematologic and cytologic investigation.

[The neurosurgical treatment of the cerebral localisations of the alveolaris (multilocularis) echinococcosis (author's transl)]. / Exérèse chirurgicale des localisations cérébrales de l'échinococcose multiloculaire.

A case of adult woman surgically treated for hepatic alveolaris ecchinococcosis on 1975 is presented. On 1976, a hypertensive intracranial syndrome is treated by removal of a right temporal kystic localisation. On 1977, a new localisation is successfully raised. The authors, in a short review of the literature note that these cerebral localisations are not always terminal. The alveolaris ecchinococcosis is now autochthonous in France.

Surface oscillations and slow crack growth controlled by creep dynamics of necking instability in a glassy film.

We study experimentally the slow growth of a single crack in a glassy film of polycarbonate submitted to uniaxial and constant imposed load. Flame-shaped macroscopic zones of plastic deformation appear at the tips of the crack and the formation of these plastic zones involves a necking instability. In order to understand the crack growth dynamics, we study first the growth dynamics of the plastic zones alone, i.e. without crack, at constant imposed load. We find that the growth velocity of the neck can be very well described by the same Eyring's factor as the one describing the creep flow of polycarbonate. In addition, we discover that a surface oscillation with a very large wavelength-to-amplitude ratio occurs during the neck propagation, and that both wavelength and amplitude are proportional to the film thickness. Finally, we succeed in modelling analytically the dependence of the instantaneous crack velocity on experimental variables using Dugdale-Barenblatt static description of crack tip plastic zones associated to Eyring's law and an empirical dependence on the crack length that may come from a residual elastic field.

Discrepancy between subcritical and fast rupture roughness: a cumulant analysis.

Rough crack fronts in a sheet of paper, obtained during a creep experiment, do not follow true scaling laws. Local roughness exponents are estimated using the first order cumulant, a quantity recently introduced in the turbulence literature [J. Delour, J. F. Muzy, and A. Arneodo, Eur. Phys. J. B 23, 243 (2001)10.1007/s100510170074]. Using a large data set (102 fronts), we find a significant difference in local roughness between the slow (subcritical) and the fast growth regime.

[Coronary complications of Horton's disease: precipitating role of corticoids?]. / Complications coronariennes de la maladie de Horton: rôle déclenchant des corticoïdes?

We report the case of an 85-year-old man with perfectly controlled hypertension and coronary insufficiency who presented with typical giant cell arteritis (GCA). Thirty-six hours after initiation of prednisolone therapy (1 mg/kg/d), acute coronary insufficiency with non-transmural infarction occurred. Outcome was favorable despite disturbances in heart rhythm. A review of the literature disclosed five cases of myocardial infarction related to GCA, confirmed upon pathological examination. Three out of five myocardial infarctions occurred between the third and seventh treatment days. These findings suggest that corticosteroids may be responsible for coronary complications which arise during the first days of GCA treatment. Furthermore, they justify close monitoring during the initial phase of treatment in patients with coronary diseases.

[Combined cefotaxime-amikacin treatment of infectious episodes in acute leukaemia patients with therapeutically-induced bone marrow aplasia (author's transl)]. / Traitement par une association céfotaxime-amikacine des épisodes infectieux des leucémies aiguës de l'adulte en aplasie thérapeutique.

In view of the clinical results obtained in severe septicaemia due to Gram-negative organisms, cefotaxime and amikacin combination was used in leukaemic patients with chemotherapeutic aplasia. 30 infectious episodes were treated in 22 cases of acute myeloid leukaemia, one case of acute flare-up in chronic leukaemia and 7 cases of acute lymphoid leukaemia. Cefotaxime was administered at daily doses of 100 mg/kg to the first 4 patients and of 60 mg/kg to the remaining 26 patients by infusion every 6 hours. Amikacin was administered at a daily dose of 15 mg/kg by the same route. 24 excellent results, 4 failures and 1 doubtful result were observed. Tolerance was very good. A new infection appeared in 9 patients during prolonged treatment (mean: 13,7 days). Cefotaxime appears to be a treatment of choice for infective conditions observed in chemotherapeutic aplastic leukaemia. A cure rate of 80% with amikacin combination can be obtained, but, in vivo, resistant pathogens (Streptococcus, group D) or poorly sensitive organisms (Pseudomonas aeruginosa + Bacteroides fragilis: 1 case) may be selected. Then, a new antibiotic treatment, based on accurate bacteriological results, could be given with success.

[Establishing a registry of malignant hemopathies in Côte-d'Or. Preliminary results]. / Mise en place d'un registre des hémopathies malignes en Côte-d'Or. Premiers résultats.

A registry of malignant haematological diseases was established on January 1st 1980 in order to assess the incidence and epidemiologic features of these diseases in the department of Côte-d'Or (population 470 000). Information was collected from various sources (public or private laboratories, public or private hospitals and death certificates). During the course of two years (1980 and 1981) 194 news cases were recorded. This registry collects acute leukaemia, lymphoid and myeloid proliferative diseases, lymphomas in leukaemic phase and myelodysplastic syndromes. The crude incidence rates were 25.0/100,000 in men and 16.1/100,000 in women. Sex ratio : 1.5. Compared to other French population based registries the incidence is higher in Côte-d'Or, showing the value of specialised registries. The rates are similar to those reported in Geneva and Connecticut.

[Antifactor VIII antibody in Rosai-Dorfman disease]. / Anticorps antifacteur VIII au cours d'une maladie de Rosai-Dorfman.

The case of a 72 year-old man with a sinus histiocytosis is reported. The clinical course was characterised by an hemorrhagic disorder linked to a factor VIII inhibitor. The characteristics of the antibody titer, affinity and saturability have been studied. In an attempt to stop the bleeding treatment included human and porcine factor VIII concentrates, plasmapheresis and immunosuppressive drugs. Repeated plasma exchanges did not modify the inhibitor titer for more than 24 h.

[Sinus histiocytosis with massive lymphadenopathy: a new case in an adult with anti factor VIII antibody (author's transl)]. / Maladie de Rosaï: forme grave chez un adulte avec présence d'un anticorps antifacteur VIII.

The case history of a 71 year old french man with a lethal sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman's Syndrome) is reported. The histological features were typical but the clinical course was remarkable because of the predominant expression was a life threatening hemorrhagic disorder closely linked to a circulating anticoagulant (anti-factor VIII). The bringing to light in a picture of hyperimmunity of a self antibody and a high anti-EBV titer suggest on lymphocyte T deficit could be important in the development of the sinus histiocytosis.