Systematic Deletion of Homeobox Genes in Podospora anserina Uncovers Their Roles in Shaping the Fruiting Body

Higher fungi, which comprise ascomycetes and basidiomycetes, play major roles in the biosphere. Their evolutionary success may be due to the extended dikaryotic stage of their life cycle, which is the basis for their scientific name: the Dikarya. Dikaryosis is maintained by similar structures, the clamp in basidiomycetes and the crozier in ascomycetes. Homeodomain transcription factors are required for clamp formation in all basidiomycetes studied. We identified all the homeobox genes in the filamentous ascomycete fungus Podospora anserina and constructed deletion mutants for each of these genes and for a number of gene combinations. Croziers developed normally in these mutants, including those with up to six deleted homeogenes. However, some mutants had defects in maturation of the fruiting body, an effect that could be rescued by providing wild-type maternal hyphae. Analysis of mutants deficient in multiple homeogenes revealed interactions between the genes, suggesting that they operate as a complex network. Similar to their role in animals and plants, homeodomain transcription factors in ascomycetes are involved in shaping multicellular structures

Echocardiography practice, training and accreditation in the intensive care: document for the World Interactive Network Focused on Critical Ultrasound (WINFOCUS)

Echocardiography is increasingly used in the management of the critically ill patient as a non-invasive diagnostic and monitoring tool. Whilst in few countries specialized national training schemes for intensive care unit (ICU) echocardiography have been developed, specific guidelines for ICU physicians wishing to incorporate echocardiography into their clinical practice are lacking. Further, existing echocardiography accreditation does not reflect the requirements of the ICU practitioner. The WINFOCUS (World Interactive Network Focused On Critical UltraSound) ECHO-ICU Group drew up a document aimed at providing guidance to individual physicians, trainers and the relevant societies of the requirements for the development of skills in echocardiography in the ICU setting. The document is based on recommendations published by the Royal College of Radiologists, British Society of Echocardiography, European Association of Echocardiography and American Society of Echocardiography, together with international input from established practitioners of ICU echocardiography. The recommendations contained in this document are concerned with theoretical basis of ultrasonography, the practical aspects of building an ICU-based echocardiography service as well as the key components of standard adult TTE and TEE studies to be performed on the ICU. Specific issues regarding echocardiography in different ICU clinical scenarios are then described

Preparation et étude de diodes laser a GaInAsSb-GaAlAsSb fonctionnant en continu à 80K

International audienc

Preparation et étude de diodes laser a GaInAsSb-GaAlAsSb fonctionnant en continu à 80K

Double heterojunctions (DH) Ga$_{0.73}$AI$_{0.27}$As$_{0.02}$Sb$_{0.98}$ ($p$)/Ga$_{0.83}$ln$_{0.17}$As$_{0.15}$ Sb$_{0.85}$ ($p$)/Ga$_{0.73}$AI$_{0.27}$AS$_{0.02}$Sb$_{0.98}$ ($n$) have been grown by liquid phase epitaxy on GaSb(100)n substrate. Confiming properties of these DH have been analyzed. Gain guided DH laser diodes have been prepared and studied by varying the temperature. Laser emission has been obtained in continuous mode up to 140K and in pulsed mode up to room temperature. Laser wavelength is 1.95 $\mu$m at 80K and 2.17 $\mu$m at 298K. The emitted power is about 1 mW. The threshold current intensity increases from 150 mA at 80K up to 1.2A at 298K, with a characteristic temperature $T_0 approx 110$K. External quantum efficiency is 6-10% per face at 80K and 1.5% per face at room temperature. Far field pattern at threshold is monolobe, with a full beam width at half power perpendicular to the junction plane $\theta_{\perp}\approx 52^{\circ}$ and in the plane ofthejunction $\theta$ //$\approx$ 11$^{\circ}$. Modelisation ofthe beam divergence $\theta_{\perp}$ allowed us to evaluate the refractive index of the active layer at threshold: $n_{\rm act} = 3.79$.Des doubles hétérojonctions (DH) Ga$_{0,73}$AI$_{0,27}$As$_{0,02}$Sb$_{0,98}$ ($p$)/Ga$_{0,83}$ln$_{0,17}$As$_{0,15}$ Sb$_{0,85}$ ($p$)/Ga$_{0,73}$AI$_{0,27}$AS$_{0,02}$Sb$_{0,98}$ ($n$) ont été obtenues par épitaxie en phase liquide sur substrat GaSb (100)n. Les propriétés confinantes de ces DH ont été analysées. Des diodes laser à guidage par le gain ont été préparées et caractérisées en température. L'émission laser a été obtenue jusqu'à 140K en régime continu et jusqu'à température ambiante en régime pulsé. La longueur d'onde d'émission est centrée vers 1,95 $\mu$m à 80K et vers2,17 $\mu$m à 298K, La puissance émise est de l'ordre du mW L'intensité de courant de seuil varie de 150 mA (80K) à 1,2 A (298K) avec une température caractéristique élevée (To $\approx$ 110K) . Le rendement quantique différentiel externe est de 6 à 10 % par face à 80K et de 1,5 % par face à température ambiante. Le champ émis au seuil est monolobe avec $\theta$ //$\approx$ 11$^{\circ}$ et $\theta_{\perp}\approx 52^{\circ}$. Une modélisation du champ perpendiculaire a permis de déterminer l'indice de la couche active au seuil : $n_{\rm act} = 3,79$