Geometrical control of the magnetization direction in high aspect-ratio PdNi ferromagnetic nano-electrodes

We present a study of electron-beam evaporated Pd0.4Ni0.6 alloy thin films by means of ferromagnetic resonance measurements on extended films of varying thickness and anisotropic magnetoresistance measurements of lithographically patterned high aspect-ratio ferromagnetic electrodes, respectively. The results reveal that the direction of the magnetization strongly depends on the electrode lateral dimensions, transitioning from in-plane magnetization for extended films to out-of-the-plane magnetization for electrode widths below 2-3 microns, reaching 58 degrees off-plane for 100 nm-wide nanoelectrodes.Comment: Preprint submitted to PRB (14 pages, 4 figures

Major bacteria of community-acquired respiratory tract infections in Turkey

To determine the bacterial etiology of lower respiratory tract infections (LRTIs) in Turkey, quantitative cultures of sputum were carried out. The major pathogens for LTRIs were found to be Haemophilus influenzae, followed by Streptococcus pneumoniae and Moraxella catarrhalis. Only 6.1% of the H. inlfuenzae and all strains of M. catarrhalis were β-lactamase producers. An E-test showed that 31.2% of the S. pneumoniae strains had an intermediate resistance to penicillin, and the remaining strains were susceptible; no fully resistant strains were detected

Progression of coronary artery calcification in conventional hemodialysis, nocturnal hemodialysis, and kidney transplantation

Introduction Cardiovascular disease is the leading cause of death in end-stage renal disease (ESRD) and is strongly associated with vascular calcification. An important driver of vascular calcification is high phosphate levels, but these become lower when patients initiate nocturnal hemodialysis or receive a kidney transplant. However, it is unknown whether nocturnal hemodialysis or kidney transplantation mitigate vascular calcification. Therefore, we compared progression of coronary artery calcification (CAC) between patients treated with conventional hemodialysis, nocturnal hemodialysis, and kidney transplant recipients. Methods We measured CAC annually up to 3 years in 114 patients with ESRD that were transplantation candidates: 32 that continued conventional hemodialysis, 34 that initiated nocturnal hemodialysis (>= 4x 8 hours/week), and 48 that received a kidney transplant. We compared CAC progression between groups as the difference in square root transformed volume scores per year (Delta CAC SQRV) using linear mixed models. Reference category was conventional hemodialysis. Results The mean age of the study population was 53 +/- 13 years, 75 (66%) were male, and median dialysis duration was 28 (IQR 12-56) months. Median CAC score at enrollment was 171 (IQR 10-647), which did not differ significantly between treatment groups (P = 0.83). Compared to conventional hemodialysis, CAC progression was non-significantly different in nocturnal hemodialysis -0.10 (95% CI -0.77 to 0.57) and kidney transplantation -0.33 (95% CI -0.96 to 0.29) in adjusted models. Conclusions Nocturnal hemodialysis and kidney transplantation are not associated with significantly less CAC progression compared to conventional hemodialysis during up to 3 years follow-up. Further studies are needed to confirm these findings, to determine which type of calcification is measured with CAC in end-stage renal disease, and whether that reflects cardiovascular risk

Coronary Artery Calcification in Hemodialysis and Peritoneal Dialysis

Background: Vascular calcification is seen in most patients on dialysis and is strongly associated with cardiovascular mortality. Vascular calcification is promoted by phosphate, which generally reaches higher levels in hemodialysis than in peritoneal dialysis. However, whether vascular calcification develops less in peritoneal dialysis than in hemodialysis is currently unknown. Therefore, we compared coronary artery calcification (CAC), its progression, and calcification biomarkers between patients on hemodialysis and peritoneal dialysis. Methods: We measured CAC in 134 patients who had been treated exclusively with hemodialysis (n = 94) or peritoneal dialysis (n = 40) and were transplantation candidates. In 57 of them (34 on hemodialysis and 23 on peritoneal dialysis), we also measured CAC progression annually up to 3 years and the inactive species of desphospho-uncarboxylated matrix Gla protein (dp-ucMGP), fetuin-A, osteoprotegerin. We compared CAC cross-sectionally with Tobit regression. CAC progression was compared in 2 ways: with linear mixed models as the difference in square root transformed volume score per year (CAC SQRV) and with Tobit mixed models. We adjusted for potential confounders. Results: In the cross-sectional cohort, CAC volume scores were 92 mm(3) in hemodialysis and 492 mm(3) in peritoneal dialysis (adjusted difference 436 mm(3); 95% CI -47 to 919; p = 0.08). In the longitudinal cohort, peritoneal dialysis was associated with significantly more CAC progression defined as CAC SQRV (adjusted difference 1.20; 95% CI 0.09 to 2.31; p = 0.03), but not with Tobit mixed models (adjusted difference in CAC score increase per year 106 mm(3); 95% CI -140 to 352; p = 0.40). Peritoneal dialysis was associated with higher osteoprotegerin (adjusted p = 0.02) but not with dp-ucMGP or fetuin-A. Conclusions: Peritoneal dialysis is not associated with less CAC or CAC progression than hemodialysis, and perhaps with even more progression. This indicates that vascular calcification does not develop less in peritoneal dialysis than in hemodialysis

Tunable stress and controlled thickness modification in graphene by annealing

Graphene has many unique properties which make it an attractive material for fundamental study as well as for potential applications. In this paper, we report the first experimental study of process-induced defects and stress in graphene using Raman spectroscopy and imaging. While defects lead to the observation of defect-related Raman bands, stress causes shift in phonon frequency. A compressive stress (as high as 2.1 GPa) was induced in graphene by depositing a 5 nm SiO2 followed by annealing, whereas a tensile stress (~ 0.7 GPa) was obtained by depositing a thin silicon capping layer. In the former case, both the magnitude of the compressive stress and number of graphene layers can be controlled or modified by the annealing temperature. As both the stress and thickness affect the physical properties of graphene, this study may open up the possibility of utilizing thickness and stress engineering to improve the performance of graphene-based devices. Local heating techniques may be used to either induce the stress or reduce the thickness selectively.Comment: 19 pages, 7 figures, accepted by ACS nan

Chemically-induced Mobility Gaps in Graphene Nanoribbons: A Route for Upscaling Device Performances

We report a first-principles based study of mesoscopic quantum transport in chemically doped graphene nanoribbons with a width up to 10 nm. The occurrence of quasibound states related to boron impurities results in mobility gaps as large as 1 eV, driven by strong electron-hole asymmetrical backscattering phenomena. This phenomenon opens new ways to overcome current limitations of graphene-based devices through the fabrication of chemically-doped graphene nanoribbons with sizes within the reach of conventional lithography.Comment: Nano Letters (in press