Intra-macrophage lipid particles collected by bronchoalveolar lavage: incidence and diagnostic value

This study aimed to determine the incidence and diagnostic value of fat-laden alveolar macrophages obtained by bronchoalveolar lavage (BAL). In 128 patients, including 66 patients admitted for multiple trauma, 158 BAL were carried out. However, 41 BAL from 32 patients were excluded because of poor quality of samples (not enough macrophages, too many ciliated cells, or haemorrhage). All the patients were intubated and mechanically ventilated, having pulmonary infiltrates on the chest film. BAL samples were examined after staining with oil-red-O. They were considered to be positive when more than 5% of alveolar macrophages contained fat droplets. Among them 14 out of 47 patients (30%) without multiple trauma were positive; 7/14 had never been given any intravenous lipid infusion, and 5/14 had aspiration pneumonia (as opposed to 3/32 patients with negative BAL). Further 27 patients out of the 49 (55%) with multiple trauma were positive. Among them 10/49 had clinical evidence of fat embolism, however, only 7/10 had positive samples. All these last ten patients had been given intravenous lipid infusions. The rate of positive alveolar macrophages was correlated neither with the plasma triglyceride concentration, nor the Fracture Index Score, nor the delay between the end of the lipid infusion and the BAL. There was no significant difference in PaO2/FIO2 ratio between the patients with positive and negative BAL. Positive BAL was significantly associated with lipid infusions. The data therefore suggest that the presence of fat-laden alveolar macrophages are associated with various pathological pulmonary conditions, particularly aspiration pneumonia and lipid infusions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Identification of linear systems captured in a feedback loop

The identification of model parameters using measured input-output data from linear systems operating in a closed loop is discussed. A frequency-domain maximum likelihood estimator which takes into account the correlation between the input and output disturbances is presented. Its properties are analyzed and illustrated by simulation examples and real measurements     

Etude de l'alliage mulberry [U-7,5 Nb-2,5 Zr (% ponderaux)]. diagramme de transformation en refroidissement continu-structures et proprietes mecaniques

We have studied by dilatometry, microscopy, X-ray and electron diffraction, the phase transformations generated by controlled cooling from 900° C of the “Mulberry” alloy (U-7.5 wt%Zr). For slow cooling rates, three types of decomposition of the 7 phase appear successively: (i) Between 600°C and 550°C, grain boundaries and inclusion serve as nucleation sites for a cellular reaction, $\text{γ→α+γ}$; (ii) between 550°C and 400°C, a continuous transformation of the matrix generates an a phase in the form of Widmanstätten plates, and (iii) below 400°C, the γ phase gives rise to an α″ phase which has an ultrafine structure only imperfectly resolved by TEM. On rapid cooling, a tetragonal phase, γ₀, appears. Quenching generates the γ_S phase derived from γ, with a structure crystallizing in 143m which has been described by YakeL The various methods of investigation used have allowed us to obtain heating and cooling curves of the alloy and thus to determine phase fields. In general terms, the structures formed are similar to those obtained by isothermal annealing below 600° C. Only the γ_S phase has useful mechanical properties, notably good ductibility. The other phases are characterised by extreme brittleness.     

Photocontrolled Hierarchical Self‐Assembly of Anisotropic Micropatterns of Nanofibers onto Isotropic Surfaces

Hierarchical self‐assembly is achieved using a visible light triggered photoreaction. A pro‐gelator, α‐diketone‐2,3‐didecyloxyanthracene, is photoconverted into a low molecular weight gelator, 2,3‐didecyloxyanthracene (DDOA), that self‐assembles into nanofibers. Spatial confinement and patterns of these nanofibers onto a surface are achieved by localizing initial nucleation with a focused laser and photogenerate subsequent fiber growth with the laser or gentler wide‐field irradiation. Remarkably, collective growth of nanofibers results in anisotropic micropatterns with orientation factors (OF) reaching 79%, resulting in collective emission of linearly polarized light. The OF, distance of collective growth and fiber density, are controlled by the photoirradiation conditions and the balance of interactions between DDOA aggregates and the glass surface. An unprecedented juxtaposition of orthogonally oriented nanofiber patterns on an isotropic surface is achieved with individual control of the fibers' main direction. In perspective, this photochemical method can be extended to a large variety of self‐assembling molecules.