We present a systematic study of the morphology of homoepitaxial InP films grown by metalorganic vapor-phase epitaxy which are imaged with ex situ atomic force microscopy. These films show a dramatic ...range of different surface morphologies as a function of the growth conditions and substrate (growth temperature V/III ratio, and miscut angle < 0.6degrees and orientation toward A or B sites), ranging from stable step flow to previously unreported strong step bunching, over 10 nm in height. These observations suggest a window of growth parameters for optimal quality epitaxial layers. We also present a theoretical model for these growth modes that takes account of deposition, diffusion, and dissociation of molecular precursors, and the diffusion and step incorporation of atoms released by the precursors. The experimental conditions for step flow and step bunching are reproduced by this model, with the step bunching instability caused by the difference in molecular dissociation from above and below step edges, as was discussed previously for GaAs (001).
Background and Study Aims. GAVE is an uncommon cause of upper nonvariceal bleeding and often manifests itself as occult bleeding with chronic anemia. To date, the standard of care for GAVE is ...endoscopic treatment with thermoablative techniques. Despite good technical results, approximately two thirds of patients remain dependent on transfusions after the therapy. One of the emerging and more promising endoscopic treatments for GAVE is radiofrequency ablation (RFA). The aim of this study is to perform a systematic review of literature in order to assess current evidence supporting the effectiveness of this technique for treatment of refractory GAVE. Materials and Methods. Through electronic search, we identified 14 records, and after removal of duplicates and irrelevant studies, we selected 10 studies on radiofrequency ablation of GAVE: 4 prospective open-label single-center studies, 1 retrospective multicentric study, and 5 case reports. Results. Among all 72 treated patients reported in literature, 74.3% achieved a clinical response, while nonfatal AEs have been reported in 4.2% of cases. Conclusions. Despite some qualitative limitations, all literature data support effectiveness of RFA for treatment of refractory GAVE. In the future, large prospective controlled trials with adequate follow-up are needed to better assess the effectiveness and safety of this procedure.
Renal involvement in systemic amyloidosis Bergesio, F.; Ciciani, A. M.; Manganaro, M. ...
Nephrology, dialysis, transplantation,
03/2008, Volume:
23, Issue:
3
Journal Article
Peer reviewed
Background. Few data are available from large population-based studies on survival and renal outcome of patients with renal involvement and different types of systemic amyloidosis. Methods. Two ...hundred and ninety of over 373 patients affected from systemic amyloidosis with renal involvement diagnosed in Italy between January 1995 and December 2000 were followed from diagnosis to death or until the last available clinical control. Eighty-three patients were excluded from analysis either because the amyloid type remained undetermined or they were lost at follow-up. Clinical and laboratory information was collected according to the different types of amyloidosis using a specific form which included renal function with 24 h proteinuria at diagnosis and at the end of follow-up, the type and the date of onset of dialysis and the kind of treatment they underwent. Results. The median time of follow-up was 24 months in primary (AL) amyloidosis (range: 1–88 months), 16 months in AL with associated multiple myeloma (MM + AL: range 1–76 months), 30 months in reactive (AA) amyloidosis (range: 1–99 months) and 52 months in patients with familial forms (AF: range 14–82 months). Patients with AL showed a significantly shorter survival than AA. Despite no significant differences of renal outcome or survival on dialysis being observed between the two groups, a lower renal survival with a higher number of patients who progressed to end-stage renal disease (ESRD) was observed in patients with AA. Overall survival was markedly improved in patients with AL who underwent a specific therapy (conventional chemotherapy or autologous stem cell transplantation (ASCT)) even in the absence of a positive kidney response. Multivariate analysis showed cardiac involvement and specific therapy to significantly influence survival in AL whereas age, serum creatinine (sCr) and heart involvement significantly affected survival in AA. In both groups, sCr and heart involvement were the most relevant predictors for renal outcome, together with urinary protein excretion, in patients with AA. Conclusions. Our results show a worse survival in AL due to the higher prevalence of heart involvement in this group and emphasize that a specific therapy significantly prolongs survival and slows the progression of renal disease in patients with AL. We suggest that a late nephrological referral is likely the cause of the higher sCr found at presentation in patients with AA and probably accounts for the lower renal survival observed in the short term in these patients. At the time being, renal transplantation and ASCT are still rare therapeutic options for renal patients affected from systemic amyloidosis.
The discovery of an astrophysical flux of high-energy neutrinos by the IceCube Collaboration marks a major breakthrough in the ongoing search for the origin of cosmic rays. Presumably, the neutrinos, ...together with gamma rays, result from pion decay, following hadronic interactions of protons accelerated in astrophysical objects to ultra-relativistic energies. So far, the neutrino sky map shows no significant indication of astrophysical sources. Here, we report first results from follow-up observations, of sky regions where IceCube has detected muon tracks from energetic neutrinos, using the MAGIC telescopes which are sensitive to gamma rays at TeV energies. Furthermore, we show that MAGIC has the potential to distinguish air showers induced by tau neutrinos from the background of hadronic showers in the PeV-EeV energy range, employing a novel analysis method to the data obtained with high-zenith angle observations.
The possibility of anisotropies in the speed of light relative to the limiting speed of electrons is considered. The absence of sidereal variations in the energy of Compton-edge photons at the ...European Synchrotron Radiation Facility's GRAAL facility constrains such anisotropies representing the first nonthreshold collision-kinematics study of Lorentz violation. When interpreted within the minimal standard-model extension, this result yields the two-sided limit of 1.6×10(-14) at 95% confidence level on a combination of the parity-violating photon and electron coefficients (κ(o+))(YZ), (κ(o+))(ZX), c(TX), and c(TY). This new constraint provides an improvement over previous bounds by 1 order of magnitude.
The $\Sigma$ beam asymmetry in $\eta^{\prime}$ photoproduction off the proton was measured at the GrAAL polarized photon beam with incoming photon energies of 1.461 and 1.480 GeV. For both energies ...the asymmetry as a function of the meson emission angle shows a clear structure, more pronounced at the lowest one, with a change of sign around 90$^o$. The results are compared to the existing theories that fail to account for the data.
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