ALBERT

Description: Hematite (α-Fe 2 O 3 ) thin films were prepared by sol-gel route and investigated for application in H 2 generation by photo-assisted water splitting. The photoelectrochemical (PEC) performance was shown to increase significantly for films deposited on SnO 2 :F/glass subjected to high temperature (T) annealing (〉750 °C). Strong correlation was found between photogenerated current, donor concentration, and Sn concentration as determined by Mott-Schottky analysis and X-ray photoelectron spectroscopy. The effects of thermal annealing and Sn addition in the resulting microstructure and optical properties of hematite films deposited on fused silica substrates were determined by a combination of structural characterization techniques and spectroscopic ellipsometry. Thermal annealing (〉600 °C) induces a higher optical absorption that is associated directly to film densification and grain growth; however, it promotes no changes in the energy positions of the main Fe 2 O 3 electronic transitions. The band gap energy was found to be 2.21 eV and independent of microstructure and of Sn concentration for all studied films. On the other hand, Sn can be incorporated in the Fe 2 O 3 lattice for concentration up to Sn/Fe ∼2%, leading to an increase in energy split of the main absorption peak, attributed to a distortion of the Fe 2 O 3 lattice. For higher concentrations, Sn incorporation leads to a reduction in absorption, associated with higher porosity and the formation of a secondary Sn-rich phase. In summary, the variation in the optical properties induced by thermal annealing and Sn addition cannot account for the order of magnitude increase of the current density generated by photoanodes annealed at high T (〉750 °C); thus, it is concluded that the major contribution for the enhanced PEC performance comes from improved electronic properties induced by the n-type doping caused by Sn diffusion from the SnO 2 :F substrate.

Description: Asymptotic behavior (with respect to the number of trials) of symmetric generalizations of binomial distributions and their related entropies is studied through three examples. The first one has the q -exponential as the generating function, the second one involves the modified Abel polynomials, and the third one has Hermite polynomials. We prove analytically that the Rényi entropy is extensive for these three cases, i.e., it is proportional (asymptotically) to the number n of events and that q -exponential and Hermite cases have also extensive Boltzmann-Gibbs. The Abel case is exceptional in the sense that its Boltzmann-Gibbs entropy is not extensive and behaves asymptotically as the square root of n . This result is obtained numerically and also confirmed analytically, under reasonable assumptions, by using a regularization of the beta function and its derivative. Probabilistic urn and genetic models are presented for illustrating this remarkable case.

Description: Abstract 4841 Myelodysplastic syndromes (MDS) are a group of acquired clonal stem cell disorders that mainly affect the elderly population, characterized by ineffective hematopoiesis and high risk of leukemic transformation. MDS are heterogeneous in terms of morphology, clinical features and survival. An increasing body of work reveals that there might be differences in clinical features between Asian and Western cases. Japanese patients seem to be younger, have a lower frequency of refractory anemia (RA) with ringed sideroblast (RARS) and a higher frequency of RA, according to FAB classification, as well as different prognostic factors such as the frequency of cytogenetic abnormalities. Incidence rates for MDS in Brazil are unavailable. The purpose of the study was to obtain epidemiological data of MDS adult patients who presented from January 2003 to December 2007 in 10 Brazilian tertiary-care hematology centers from different regions of the country. Patient data collected by participating physicians were entered and stored with the use of an internet-based, data collection tool. Blood counts, bone marrow aspiration, trephine biopsy and chromosomal study were recorded. Survival was estimated through Kaplan-Meier method and the difference between survival curves was assessed by means of Log-Rank Test. Death incidence rates were estimated and compared. Statistical analyses of relevant variables were performed. Three hundred and forty three patients with diagnosis of MDS according to FAB/WHO classification were included in this retrospective analysis. The mean age at presentation was 68 years (range 17 to 98). Fifty percent of cases were male. Cigarette smoking, alcohol abuse and pesticide/herbicide exposure were reported in 33.5%, 13.4% and 14.3% respectively. Median hemoglobin was 8.7 g/dL, median neutrophils count was 1,575/mm3 and median platelets count was 97,000/mm3. There was no excess of blasts in 68.4% of cases. Bone marrow biopsy was performed in 78.5% of patients. Lymphoid nodules were seen in 11.3% and any degree of fibrosis in 28.6%. Cytogenetic analysis was performed in 67.8% of cases and showed chromosomal abnormalities in 50.5%. The del(5q) isolated or combined with other alterations were observed in 6.0%. Flow cytometry analysis for CD55 and CD59 was performed in 11,3% and was normal in 97,4%. Near 8% of cases were classified as secondary MDS. The distribution of disease subtypes according to FAB classification was: RA 42,3%, RARS 9,0%, RA with excess of blasts (RAEB) 20,7%, RAEB-t 4,2% and chronic myelomonocytic leukemia (CMML) 3,9%. According to IPSS patients were stratified as low-risk (low risk plus intermediate I) 55,9% and high risk (intermediate II and high risk) 13,1%. In 30,1% no stratification was possible. In 26,5% of cases iron overload was diagnosed although only 28,3% of cases had performed serum ferritin. The follow-up time ranged from 1 to 78 months (mean: 28 months). Thirty-six percent of patients died and the death was MDS-related in 68.3% of cases. The high and low risk survival curves were significantly different (p

Description: Key Points Elevated levels of BCA-1, sTNFR2, and sVEGFR2 are associated with increased risk for NHL several years after blood collection.