Patterning-induced strain relief in single lithographic SiGe nanostructures studied by nanobeam x-ray diffraction.

The continued downscaling in SiGe heterostructures is approaching the point at which lateral confinement leads to a uniaxial strain state, giving high enhancements of the charge carrier mobility. Investigation of the strain relaxation as induced by the patterning of a continuous SiGe layer is thus of scientific and technological importance. In the present work, the strain in single lithographically defined low-dimensional SiGe structures has been directly mapped via nanobeam x-ray diffraction. We found that the nanopatterning is able to induce an anisotropic strain relaxation, leading to a conversion of the strain state from biaxial to uniaxial. Its origin is fully compatible with a pure elastic deformation of the crystal lattice without involving plastic relaxation by injection of misfit dislocations.

Non-destructive and quantitative imaging of a nano-structured microchip by ptychographic hard X-ray scanning microscopy.

We used hard X-ray scanning microscopy with ptychographic coherent diffraction contrast to image a front-end processed passivated microchip fabricated in 80 nm technology. No sample preparation was needed to image buried interconnects and contact layers with a spatial resolution of slightly better than 40 nm. The phase shift in the sample is obtained quantitatively. With the additional knowledge of the elemental composition determined in parallel by X-ray fluorescence mapping, quantitative information about specific nanostructures is obtained. A significant enhancement in signal-to-noise ratio and spatial resolution is achieved compared to conventional hard X-ray scanning microscopy.

Coherent x-ray diffraction imaging with nanofocused illumination.

Coherent x-ray diffraction imaging is an x-ray microscopy technique with the potential of reaching spatial resolutions well beyond the diffraction limits of x-ray microscopes based on optics. However, the available coherent dose at modern x-ray sources is limited, setting practical bounds on the spatial resolution of the technique. By focusing the available coherent flux onto the sample, the spatial resolution can be improved for radiation-hard specimens. A small gold particle (size <100 nm) was illuminated with a hard x-ray nanobeam (E=15.25 keV, beam dimensions approximately 100 x 100 nm2) and is reconstructed from its coherent diffraction pattern. A resolution of about 5 nm is achieved in 600 s exposure time.

[Practice and complications of spinal anesthesia in African tropical countries]. / Pratique et complications de la rachianesthésie en milieu tropical africain.

OBJECTIVE: To evaluate the risk of the practice of spinal anaesthesia (SA) in African tropics. STUDY DESIGN: Prospective study in multiple centres over a two years period. PERSONS: Twenty-one anaesthesiologists and anaesthetist nurses covering ten African countries. METHODS: Two anonymous questionnaires; the first, filled in each anaesthetic problem occurred, to define the type of incident or accident, and its circumstances; the second was designed to define the position occupied, to quantify the global anaesthetic activity, the number of SA, and to value the number of complications or deaths linked to SA. RESULTS: Six anaesthesiologists and one anaesthetist nurse replied to the study, covering six sites in five different countries (Senegal, Chad, Central African Republic, Niger and Madagascar). On the 18,432 anaesthetic acts collected, 2,703 (14.7%) were SA. In the well-equipped centres, general anaesthesia was predominant with a frequency of over 75%. However in the not so well equipped centres or those which supplies were more problematical, SA technique was used with a frequency varying from 48.9 to 68.7%. Forty incidents and accidents were reported (1.5%), five led to the death of the patient (0.2%). Among the seven cardiac arrests (0.3%), four were fatal (0.1%). Eight of the ten accidents and all of the deaths occurred in the least equipped centres. Eight of ten accidents happened during emergency caesarean sections. All cardiac arrests were preceded by a severe hypovolemia. For the four deaths after cardiac arrest, an anaesthetist nurse with isobaric bupivacaine 0.5% carried out SA. CONCLUSIONS: This study showed that the practice of SA in African tropics was performing in different practice conditions and people qualification than they were in France. The frequency of cardiac arrests and deaths was respectively five and 20 times more important, in those conditions. The first conclusion that can be drawn from this study is that it is questionable to use SA for emergency Caesarean section under hypovolemic condition. The second is the necessity for specific training on the local anaesthesia for anaesthetist nurses but also training to choose the anaesthesia best adapted to the surgery, the condition of the patient and the means available.

Adrenomedullin and myocardial contractility in the rat.

The effects of adrenomedullin in the regulation of myocardial contractility were investigated in the rat. In papillary muscles (n=6), adrenomedullin (0.1 to 10 nM) failed to show contractile effects. NO (nitric oxide) synthase inhibition with N(G)-nitro-L-arginine (L-NOARG) did not unmask any inotropic effect of adrenomedullin. The positive inotropic effect of isoprenaline (0. 01 nM to 10 microM) was identical after adrenomedullin, after L-NOARG, and after L-NOARG plus adrenomedullin (n=6 each). In field-stimulated rat ventricular myocytes, adrenomedullin (1, 10, and 100 nM; n=4 each) had impact neither on cell shortening nor on Ca(2+) transients. In isolated constant-flow perfused hearts (7.3+/-0.3 ml/min), adrenomedullin (1 nM, n=9; 10 nM, n=7) induced significant coronary vasodilation (-28%, -50%). In conclusion, adrenomedullin is a potent coronary vasodilator, but has no significant effects on myocardial contractility in the rat.

[Mc Kee total hip arthroplasty. A review of 1,000 cases (author's transl)]. / Prothèses totales de hanche de Mac Kee. 1 000 cas opérés de 1967 à 1977.

The authors have inserted Mc Kee prostheses in 1,000 hips between 1967 and 1977. 616 were reviewed with a follow-up of more than three years. There was an overall infection rate of 2.4 p. cent and of 4.3 p. cent in cases which had previously had operations. The results were satisfactory with 84.7 p. cent giving no pain, using no sticks and with good mobility. 83 cases were reviewed with more than ten years follow-up. 3 out of 4 still have a satisfactory result. Only 14 cases had to be operated on for a second time for loosening with 11 satisfactory results. It is concluded that this type of prosthesis is valuable when compared with other types. Very little wear and no fracture of the stem was seen.