Compared efficacy of preservation solutions in liver transplantation: A long-term graft outcome study from the european liver transplant registry

International audienceBetween 2003 and 2012, 42 869 first liver transplantations performed in Europe with the use of either University of Wisconsin solution (UW; N = 24 562), histidine-tryptophan-ketoglutarate(HTK; N = 8696), Celsior solution (CE; N = 7756) or Institute Georges Lopez preservation solution (IGL-1; N = 1855) preserved grafts. Alternative solutions to the UW were increasingly used during the last decade. Overall, 3-year graft survival was higher with UW, IGL-1 and CE (75%, 75% and 73%, respectively), compared to the HTK (69%) (p 12 h or grafts used for patients with cancer (p < 0.0001). For partial grafts, 3-year graft survival was 89% for IGL-1, 67% for UW, 68% for CE and 64% for HTK (p = 0.009). Multivariate analysis identified HTK as an independent factor of graft loss, with recipient HIV (+), donor age ≥65 years, recipient HCV (+), main disease acute hepatic failure, use of a partial liver graft, recipient age ≥60 years, no identical ABO compatibility, recipient hepatitis B surface antigen (-), TIT ≥ 12 h, male recipient and main disease other than cirrhosis. HTK appears to be an independent risk factor of graft loss. Both UW and IGL-1, and CE to a lesser extent, provides similar results for full size grafts. For partial deceased donor liver grafts, IGL-1 tends to offer the best graft outcome

Structural and optical properties of (In,Ga)As/GaP quantum dots and (GaAsPN/GaPN) diluted-nitride nanolayers coherently grown onto GaP and Si substrates for photonics and photovoltaics applications

San Francisco, California, United StatesInternational audienceLattice-matched GaP-based nanostructures grown on silicon substrates is a highly rewarded route for coherent integration of photonics and high-efficiency photovoltaic devices onto silicon substrates. We report on the structural and optical properties of selected MBE-grown nanostructures on both GaP substrates and GaP/Si pseudo-substrates. As a first stumbling block, the GaP/Si interface growth has been optimised thanks to a complementary set of thorough structural analyses. Photoluminescence and time-resolved photoluminescence studies of self-assembled (In,Ga)As quantum dots grown on GaP substrate demonstrate a proximity of two different types of optical transitions interpreted as a competition between conduction band states in X and Γ valleys. Structural properties and optical studies of GaAsP(N)/GaP(N) quantum wells coherently grown on GaP substrates and GaP/Si pseudo substrates are reported. Our results are found to be suitable for light emission applications in the datacom segment. Then, possible routes are drawn for larger wavelengths applications, in order to address the chip-to-chip and within-a-chip optical interconnects and the optical telecom segments. Finally, results on GaAsPN/GaP heterostructures and diodes, suitable for PV applications are reporte

Interpretation of the two-components observed in high resolution X-ray diffraction ω scan peaks for mosaic ZnO thin fi lms grown on c-sapphire substrates using pulsed laser deposition

International audienceX-ray scattering methods were applied to the study of thin mosaic ZnO layers deposited on c-Al 2 O 3 substrates using Pulsed Laser Deposition. High Resolution (HR) studies revealed two components in the ω scans (transverse scans) which were not resolved in conventional "open-detector" ω rocking curves: a narrow, resolution-limited, peak, characteristic of long-range correlation, and a broad peak, attributed to defect- related diffuse-scattering inducing a limited transverse structural correlation length. Thus, for such mosaic fi lms, the conventional ω rocking curve Full Width at Half Maximum linewidth was found to be ill-adapted as an overall fi gure-of-merit for the structural quality, in that the different contributions were not meaningfully represented. A "Williamson-Hall like" integral breadth (IB) metric for the HR (00.l) transverse-scans was thus developed as a reliable, fast, accurate and robust alternative to the rocking curve linewidth for routine non- destructive testing of such mosaic thin fi lms. For a typical ZnO/c-Al 2 O 3 fi lm, the IB method gave a limited structural correlation length of 110 nm±9 nm. The results are coherent with a thin fi lm containing mis fi t dislocations at the fi lm-substrate interface

Structural and morphological evolution of Co on faceted Pt/W(111) surface upon thermal annealing

International audienceThe structural and morphological changes of a 1.1 monolayer (ML) Pt deposit on W(1 1 1) have been investigated in situ, in ultra-high vacuum, as a function of the annealing temperature from 700 to 1340 K, by a combination of grazing incidence X-ray diffraction and grazing incidence small-angle X-ray scattering. Before annealing, the thin Pt layer is two-dimensional and lattice-matched to the W(1 1 1) surface. The faceting of Pt/W(1 1 1) towards nanoscale three-sided pyramids with {2 1 1} facets has been detected from 715 K. At this stage, the pyramids, which have a 5-nm average lateral size, cover nearly perfectly the surface. At higher temperatures, they increase in size. The role of the edge energy in the nanofaceting process is discussed. In addition, 4 MLs Co are deposited at room temperature on the smallest Pt/W pyramids. The obtained three-dimensional Co islands are correlated with the Pt/W nanopyramids and Co is relaxed on Pt/W. At approximately 800 K, a CoPt alloy is formed and becomes better ordered as the annealing temperature increases. At 1100 K, both defaceting and phase separation begin; the CoPt alloy segregates on the W(1 1 1) flat surface, while Co forms an epitaxial layer on the {2 1 1} facets. In addition, in the temperature range of 1100–1200 K, a great majority of {2 1 1} large facets coexist with some {1 1 0} small facets. Finally, the surface becomes flat again at 1250 K

Self-Organized Growth of Nanoparticles on a Surface Patterned by a Buried Dislocation Network

International audienceThe self-organized growth of Co nanoparticles is achieved at room temperature on an inhomogenously strained Ag(001) surface arising from an underlying square misfit dislocation network of 10 nm periodicity buried at the interface between a 5 nm-thick Ag film and a MgO(001) substrate. This is revealed by in situ grazing-incidence small-angle x-ray scattering. Simulations of the data performed in the distorted wave Born approximation framework demonstrate that the Co clusters grow above the dislocation crossing lines. This is confirmed by molecular dynamic simulations indicating preferential Co adsorption on tensile sites

Coherent

Frozen-in phason fluctuations in single grains of icosahedral \chem{Al}-\chem{Pd}-\chem{Mn} quasicrystals have been studied by high-resolution coherent X-ray scattering. Bragg peak widths scale as expected for a distribution of uniform phason strains. Strong relaxation of the uniform phason strain is observed after sample annealing. Large intensity fluctuations or speckle patterns are observed in the Bragg peaks due to the uniform phason strain distribution in the sample. Speckle patterns are also observed in the diffuse scattering located close to the Bragg reflections and are related to long-wavelength phason fluctuations taking place in the sample

Studies of PLD-grown ZnO and MBE-grown GaP mosaic thin films by x-ray scattering methods: beyond the restrictive omega rocking curve linewidth as a figure-of-merit

International audienceX-ray scattering methods were applied to the study of thin mosaic ZnO layers deposited by Pulsed Laser Deposition on c-Al2O3 substrates and thin mosaic GaP layers deposited by Molecular Beam Epitaxy (MBE) on Si(001) substrates. For both systems, High Resolution (HR) studies revealed two components in the ω scans (transverse scans) which were not resolved in conventional "open-detector" ω rocking curves: a narrow, resolution-limited, peak, characteristic of longrange correlation, and a broad peak, due to defect-related diffuse-scattering giving a limited transverse structural correlation length. Thus, for such mosaic films, the conventional ω rocking curve Full Width at Half Maximum linewidth was found to be inadapted as an overall figure-of-merit for the structural quality, in that, first, the different contributions were not meaningfully represented, and, second, the linewidth depends more strongly on the film thickness than on the dispersion in the crystallographic orientation or the defect density. A "Williamson-Hall like" integral breadth (IB) metric for the HR (00.l) transverse-scans was developed as a reliable, fast, accurate and robust alternative to the rocking curve linewidth for routine non-destructive testing of such mosaic thin films. For ZnO/c-Al2O3 films of various thicknesses, it was deduced from the transverse scans profiles that this finite lateral correlation length may arise from misfit dislocations which accommodate the lattice-mismatch at the film-substrate interface. This WHL method is shown to be a generic approach applicable to the study of other mosaic, epitaxial, thin-film systems as illustrated through the study of mosaic GaP thin films grown by MBE on Si(001) 4°-off substrates. For this heterogeneous system, it was found from the transverse scan profiles around (002) and (006) that anti-phase crystalline domains can be evidenced. A finite correlation length associated with lateral anti-phase domain size was proposed