Angular dependence of domain wall resistivity in SrRuO3_{{\bf 3}} films

${\rm SrRuO_3}$ is a 4d itinerant ferromagnet (T$_{c}$ $\sim$150 K) with stripe domain structure. Using high-quality thin films of SrRuO$_{3}$ we study the resistivity induced by its very narrow ($\sim 3$ nm) Bloch domain walls, $\rho_{DW}$ (DWR), at temperatures between 2 K and T$_{c}$ as a function of the angle, $\theta$, between the electric current and the ferromagnetic domains walls. We find that $\rho_{DW}(T,\theta)=\sin^2\theta \rho_{DW}(T,90)+B(\theta)\rho_{DW}(T,0)$ which provides the first experimental indication that the angular dependence of spin accumulation contribution to DWR is $\sin^2\theta$. We expect magnetic multilayers to exhibit a similar behavior.Comment: 5 pages, 5 figure

Mesoscopic Tunneling Magnetoresistance

We study spin-dependent transport through ferromagnet/normal-metal/ferromagnet double tunnel junctions in the mesoscopic Coulomb blockade regime. A general transport equation allows us to calculate the conductance in the absence or presence of spin-orbit interaction and for arbitrary orientation of the lead magnetizations. The tunneling magnetoresistance (TMR), defined at the Coulomb blockade conductance peaks, is calculated and its probability distribution presented. We show that mesoscopic fluctuations can lead to the optimal value of the TMR.Comment: 5 pages, 3 eps figures included using epsf.sty. Revised text and improved notation, fig. 2 removed, explicit equations for the GSE case adde

Oscillatory biquadratic coupling in Fe/Cr/Fe(001)

Copyright © 1997 The American Physical SocietyPolar Kerr measurements have been used to measure the dependence of the biquadratic coupling strength B12 on Cr thickness in an Fe/Cr/Fe trilayer. The overall behavior, which consists of a maximum coupling strength at dCr=5 Å (3.5 ML) with a falloff at greater Cr thicknesses, is found to be consistent with in-plane Kerr and Brillouin light-scattering measurements performed on the same sample. The polar Kerr measurements suggest additionally that B12 increases from zero near zero Cr thickness, and that it oscillates in magnitude after the first peak, with a second peak in B12 occurring at about dCr=12 Å (8.3 ML). The positions and heights of the first and second biquadratic coupling maxima, in relation to the first bilinear coupling maximum, show excellent agreement with previous measurements by Köbler et al. of the biquadratic coupling behavior in Fe/Cr/Fe, and also show good agreement with the predictions of an intrinsic biquadratic coupling mechanism due to Edwards et al

Factors associated with low bone mass in the hemodialysis patients – a cross-sectional correlation study

<p>Abstract</p> <p>Background</p> <p>Low bone mass is common in end-stage renal disease patients, especially those undergoing hemodialysis. It can lead to serious bone health problems such as fragility fractures. The purpose of this study is to investigate the risk factors of low bone mass in the hemodialysis patients.</p> <p>Methods</p> <p>Sixty-three subjects on hemodialysis for at least 6 months were recruited from a single center for this cross-sectional study. We collected data by questionnaire survey and medical records review. All subjects underwent a bone mineral density (BMD) assay with dual-energy x-ray absorptiometry at the lumbar spine and right hip. Data were statistically analyzed by means of descriptive analysis, independent t test and one way analysis of variance for continuous variables, Pearson product-moment correlation to explore the correlated factors of BMD, and stepwise multiple linear regression to identify the predictors of low bone mass.</p> <p>Results</p> <p>Using WHO criteria as a cutoff point, fifty-one subjects (81%) had a T-score lower than -1, of them 8 subjects (13%) had osteoporosis with the femoral neck most commonly affected. Regarding risk factors, age, serum alkaline phosphatase (ALP) level, and intact parathyroid hormone (iPTH) level had significant negative correlations with the femoral neck and lumbar spine BMD. On the other hand, serum albumin level, effective exercise time, and body weight (BW) had significant positive correlations with the femoral neck and lumbar spine BMD. Age, effective exercise time, and serum albumin level significantly predicted the femoral neck BMD (R²× 0.25), whereas BW and the ALP level significantly predicted the lumbar spine BMD (R²× 0.20).</p> <p>Conclusion</p> <p>This study showed that advanced age, low BW, low serum albumin level, and high ALP and iPTH levels were associated with a low bone mass in the hemodialysis patients. We suggest that regular monitoring of the femoral neck BMD, maintaining an adequate serum albumin level and BW, and undertaking an exercise program are important to improve bone health in the patients undergoing hemodialysis.</p

Temporal changes in the epidemiology, management, and outcome from acute respiratory distress syndrome in European intensive care units: a comparison of two large cohorts

Background: Mortality rates for patients with ARDS remain high. We assessed temporal changes in the epidemiology and management of ARDS patients requiring invasive mechanical ventilation in European ICUs. We also investigated the association between ventilatory settings and outcome in these patients. Methods: This was a post hoc analysis of two cohorts of adult ICU patients admitted between May 1–15, 2002 (SOAP study, n = 3147), and May 8–18, 2012 (ICON audit, n = 4601 admitted to ICUs in the same 24 countries as the SOAP study). ARDS was defined retrospectively using the Berlin definitions. Values of tidal volume, PEEP, plateau pressure, and FiO2 corresponding to the most abnormal value of arterial PO2 were recorded prospectively every 24&nbsp;h. In both studies, patients were followed for outcome until death, hospital discharge or for 60&nbsp;days. Results: The frequency of ARDS requiring mechanical ventilation during the ICU stay was similar in SOAP and ICON (327[10.4%] vs. 494[10.7%], p = 0.793). The diagnosis of ARDS was established at a median of 3 (IQ: 1–7) days after admission in SOAP and 2 (1–6) days in ICON. Within 24&nbsp;h of diagnosis, ARDS was mild in 244 (29.7%), moderate in 388 (47.3%), and severe in 189 (23.0%) patients. In patients with ARDS, tidal volumes were lower in the later (ICON) than in the earlier (SOAP) cohort. Plateau and driving pressures were also lower in ICON than in SOAP. ICU (134[41.1%] vs 179[36.9%]) and hospital (151[46.2%] vs 212[44.4%]) mortality rates in patients with ARDS were similar in SOAP and ICON. High plateau pressure (&gt; 29 cmH2O) and driving pressure (&gt; 14 cmH2O) on the first day of mechanical ventilation but not tidal volume (&gt; 8&nbsp;ml/kg predicted body weight [PBW]) were independently associated with a higher risk of in-hospital death. Conclusion: The frequency of and outcome from ARDS remained relatively stable between 2002 and 2012. Plateau pressure &gt; 29 cmH2O and driving pressure &gt; 14 cmH2O on the first day of mechanical ventilation but not tidal volume &gt; 8&nbsp;ml/kg PBW were independently associated with a higher risk of death. These data highlight the continued burden of ARDS and provide hypothesis-generating data for the design of future studies

Glomerular permselectivity in proteinuric patients after kidney transplantation.

To characterize the defect in glomerular permselectivity responsible for proteinuria after renal transplantation, we studied 10 patients with moderate proteinuria (median 0.37 g/d, range 0.20-0.79), 16 patients with the nephrotic syndrome (6.73 g/d, 3.9-14.6), 8 living related donor transplant recipients without any history of rejection (median proteinuria 0.26 g/d, 0.06-0.58), and 12 healthy volunteers. The fractional clearance of neutral dextrans > 54 A was significantly higher in nephrotic patients, demonstrating a defect in glomerular size selectivity. Using a log-normal model of glomerular pore size distribution, r*(5%) and r*(1%), indices for the presence of large pores, were increased in the nephrotic patients. The fractional clearance of negatively charged dextran sulfate was significantly higher in all patient groups, indicating a loss of glomerular charge selectivity. Biopsy findings showed more prominent glomerular lesions in the nephrotic group compared with the moderately proteinuric group. We conclude that mild proteinuria late after renal transplantation is associated with a defect in glomerular charge selectivity. The development of nephrotic range proteinuria is associated also with a defect of glomerular size selectivity, which correlates with prominent glomerular pathology