Magneto-optical properties and Mossbauer Investigation of BaxSryPbzFe12O19 Hexaferrites

Ba0.3Sr0.4Pb0.3Fe12O19, Ba(0.4)Sro(0.3)Ph(0.3)Fe(12)O(19) and Ba0.3Sr0.3Pb0.4Fe12O19 hexaferrites were synthesized via sol-gel auto combustion. XRD (X-ray powder diffraction) powder patterns of the products confirmed the formation of M-type hexaferrites without any secindary phase. The crystallite sizes of the products were calculated as 3741 nm by Scherrer equation. SEM (Scanning electron microscopy) analyses revelaed the hexagonal morphology and 200-400 nm grain size of the prodcuts. The magnetic hysteresis (a sigma-H) curves exhibit the ferromagnetic features for all hexaferrites. Especially, Ba0.3Sr0.4Pb0.3Fe12O19 and Ba0.4Sr0.3Pb0.3Fe12O19 samples have suitable magnetic characteristics (saturation magnetizations as 42.58 and 38.55 emu/g, coercive fields as 1950 and 2978 Oe, larger squareness ratios (SQR) as 0.447 and 0.454, respectively) for high density magnetic recording applications and permanent magnet fabrication. Effective crystalline anisotropy constants (Kell) are between 3.18x10(5) -3.54x10(5) Erg/g. The observed 17000 Oe Ha (anisotropy field) reveal that products are hard magnet. Tauc plots were plotted to determine the Eg (direct optical energy band gap) of the samples. The Eg values are 1.46, 1.51, 1.69 eV belonging to Ba0.3Sr0.4Pb0.3Fe12O19, Ba0.4Sr0.3Pb0.3Fe12O19, and Ba0.3Sr0.3Pb0.4Fe12O19 hexaferrites respectively

The outcome of non-carbapenem-based empirical antibacterial therapy and VRE colonisation in patients with hematological malignancies

Background: Febrile neutropenia (FN) is generally a complication of cancer chemotherapy. Objective: We retrospectively evaluated the febrile neutropenia episodes and their outcomes with respect to modification rates of non-carbapenem-based empirical antibacterial therapy and vancomycin-resistant enterococcus (VRE) colonisation that caused to VRE bacteremia in patients with hematological malignancies. Methods: All consecutive patients, who were older than 14 years of age and developed febrile neutropenia episodes due to hematological malignancies from September 2010 to November 2011 at the hematology department were included into the study. Results: In total, 86 consecutive neutropenic patients and their 151 febrile episodes were evaluated. The mean MASCC prognostic index score was 18,72 ± 9,43. Among 86 patients, 28 patients experienced a total of 30 bacteremia episodes of bacterial origin. Modification rates of both, empirical monotherapy and combination therapies, were found similar, statistically (P =0,840). Conclusion: Our results suggest that initiating of non-carbapenem based therapy does not provide high response rates in the treatment of febrile neutropenia attacks. Furthermore, non-carbapenem-based empirical therapy provides benefit in regard to cost-effectiveness and antimicrobial stewardship when local antibiotic resistance patterns of gram-negative bacteria are considered. Patients who are colonized with VRE are more likely to develop bacteremia with VRE strains as a result of invasive procedures and severe damage of mucosal barriers observed in this group of patients