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The changes in the X-ray Absorption Spectrum (XAS) of water upon formation of hydrogen bonds (H-bonds) are analyzed with the aid of Density Functional Theory (DFT) calculations. The tetrahedral symmetry of the ice structure removes the p-character from the 4a1 level, leading to very weak intensity in the pre-edge region. Breaking an accepting H-bond has very little effect on the absorption spectrum. A broken donating H-bond, however, is identified through a strong pre-edge feature in XAS. The asymmetry on the hydrogen side causes a1 and b2 orbital mixing and the orbitals localize along the internal O–H bonds. [Copyright &y& Elsevier]

Background Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal disorders, with very different prognosis in given individuals; age and comorbidities are emerging as relevant patient-related factors influencing clinical outcome in MDS. Our aim was to evaluate the impact of age, comorbidities and disease severity (IPSS and IPSS-R prognostic scores) in a “real-life” series of MDS patients. Methods 318 patients with available assessment of comorbidities at diagnosis and consecutively registered into the Registro Ligure delle Mielodisplasie were analyzed. Comorbidities were evaluated according to HCT-CI and MDS-CI comorbidity indexes. Overall survival (OS) and the probability of death among patients who did not develop acute myeloid leukemia (NLD cumulative incidence) were analyzed. Results Comorbidities were seen in 177 (55.7%) patients. An older age (>75 y) had a significant negative impact on OS ( p = 0.008). HCT-CI was not associated with OS. MDS-CI was of prognostic significance ( p = 0.001), but the association was limited to pts with IPSS or IPSS-R “lower-risk”. In multivariate analysis, MDS-CI remained an independent factor associated with OS and with an increased risk of NLD both when controlling for IPSS ( p = 0.019 and p = 0.001, respectively) and for IPSS-R ( p = 0.048 and p = 0.002, respectively). Conclusions Evaluation of age and comorbidities according to a tailored tool such is MDS-CI helps to predict survival in patients with MDS and should be incorporated to current prognostic scores. [ABSTRACT FROM AUTHOR]