Short-term Use of Cinacalcet in Children on Regular Hemodialysis

Introduction: Therapy with vitamin D3 analogs suppress the parathyroid hormone (PTH) secretion in chronic kidney disease (CKD) patients suffering from secondary hyperparathyroidism (sHPT). The concurrent administration of calcium-containing phosphate binders further increases the likelihood of developing hypercalcemia. Calcimimetics, such as cinacalcet, lower PTH level while limiting the risks of hyperphosphatemia and/or hypercalcemia. In adults, clinical experience with calcimimetics has shown significant reductions in PTH levels in cases with sHPT, but the clinical experience in children with CKD is limited.Case series: We report here the effect of short term use of cinacalcet on sHPT in two children on regular hemodialysis for CKD stage 5. Both children had very high PTH level which failed to be controlled with vitamin D3 and phosphate binders. We started cinacalcet therapy at a dose of 30 mg/day for both of them for duration of eight weeks. The first case was an 11 year-old male, his iPTH level decreased by 26% at four weeks after initiation of therapy and decreased by 39% at eight weeks. The second case was a 13 year-old female, her iPTH level decreased by 25% at four weeks after therapy and by 40% at eight weeks. There were no drug related side effects in both cases. Serum calcium and phosphorus levels remained stable in both patients.Conclusion: Cinacalcet can be effectively used in the treatment of sHPT in children in the short term, with minimal changes in the serum levels of calcium and phosphorus

Frequency and power dependence of spin-current emission by spin pumping in a thin film YIG/Pt system

This paper presents the frequency dependence of the spin current emission in a hybrid ferrimagnetic insulator/normal metal system. The system is based on a ferrimagnetic insulating thin film of Yttrium Iron Garnet (YIG, 200 nm) grown by liquid-phase-epitaxy (LPE) coupled with a normal metal with a strong spin-orbit coupling (Pt, 15 nm). The YIG layer presents an isotropic behaviour of the magnetization in the plane, a small linewidth, and a roughness lower than 0.4 nm. Here we discuss how the voltage signal from the spin current detector depends on the frequency [0.6 - 7 GHz], the microwave power, Pin, [1 - 70 mW], and the in-plane static magnetic field. A strong enhancement of the spin current emission is observed at low frequencies, showing the appearance of non-linear phenomena.Comment: 7 pages, 5 figure

Thermodynamical Properties of Hall Systems

We study quantum Hall effect within the framework of a newly proposed approach, which captures the principal results of some proposals. This can be established by considering a system of particles living on the non-commutative plane in the presence of an electromagnetic field and quantum statistical mechanically investigate its basic features. Solving the eigenvalue equation, we analytically derive the energy levels and the corresponding wavefunctions. These will be used, at low temperature and weak electric field, to determine the thermodynamical potential \Omega^{nc} and related physical quantities. Varying \Omega^{nc} with respect to the non-commutativity parameter \theta, we define a new function that can be interpreted as a \Omega^{nc} density. Evaluating the particle number, we show that the Hall conductivity of the system is \theta-dependent. This allows us to make contact with quantum Hall effect by offering different interpretations. We study the high temperature regime and discuss the magnetism of the system. We finally show that at \theta=2l_B^2, the system is sharing some common features with the Laughlin theory.Comment: 20 pages, misprints correcte

Posterior Reversible Encephalopathy Syndrome in a Child with Steroid Sensitive Nephrotic Syndrome

Introduction: Posterior reversible encephalopathy syndrome (PRES) was described in adults more than children. It was reported in cases of nephrotic syndrome which were mainly on immunosuppressant medicationsor had severe hypertension.Case report: We report the case of a 9-years old girl who presented with nephrotic syndrome and moderate hypertension. Nine days after the initiation of steroid therapy she developed disturbed level of consciousnessand generalized tonic clonic seizures. Her blood pressure was 145/90 mm Hg and she had normal serum creatinine and electrolytes levels. She was treated with furosemide and convulsions were controlled. After regainingconsciousness, the patient complained of loss of vision. Fundal  examination was normal. Magnetic resonant  imaging, axial FLAIR images and diffusion weighted imaging showed hyper-intensity signal in the parieto-occipital areas. Magnetic resonant arteriography and spectroscopy excluded ischemic insults and neoplastic process. She regained full consciousness and normal vision and was discharged from the ICU four days later. PRES was diagnosed based on the typical pattern of brainimaging and the reversibility of symptoms. .Conclusion: Nephrotic syndrome in children should be considered a risk factor for developing PRES even without the use of immunosuppressant agents or high doses of steroids

Magnetization reversal and spin dynamics exchange in biased F/AF bilayers probed with complex permeability spectra

The spin dynamics of the ferromagnetic pinned layer of ferro-antiferromagnetic coupled NiFe/MnNi bilayers is investigated in a broad frequency range (30 MHz-6 GHz). A phenomenological model based on the Landau-Lifshitz equation for the complex permeability of the F/AF bilayer is proposed. The experimental results are compared to theoretical predictions. We show that the resonance frequencies, measured during the magnetization, are likewise hysteretic.Comment: 4 pages, 4 figure

Spin dynamics in exchange-biased F/AF bilayers

The spin dynamics of the ferromagnetic pinned layer of ferro-antiferromagnetic coupled NiFe/MnNi bilayers is investigated in a broad frequency range (30 MHz-6 GHz). A phenomenological model based on the Landau-Lifshitz equation for the complex permeability of the F/AF bilayer is proposed. The experimental results are compared to theoretical predictions.Comment: 12 pages, 3 figures, 1 tabl

Thermal simulation of magnetization reversals for size-distributed assemblies of core-shell exchange biased nanoparticles

A temperature dependent coherent magnetization reversal model is proposed for size-distributed assemblies of ferromagnetic nanoparticles and ferromagnetic-antiferromagnetic core-shell nanoparticles. The nanoparticles are assumed to be of uniaxial anisotropy and all aligned along their easy axis. The thermal dependence is included by considering thermal fluctuations, implemented via the N\'eel-Arrhenius theory. Thermal and angular dependence of magnetization reversal loops, coercive field and exchange-bias field are obtained, showing that F-AF size-distributed exchange-coupled nanoparticles exhibit temperature-dependent asymmetric magnetization reversal. Also, non-monotonic evolutions of He and Hc with T are demonstrated. The angular dependence of Hc with T exhibits a complex behavior, with the presence of an apex, whose position and amplitude are strongly T dependent. The angular dependence of He with T exhibits complex behaviors, which depends on the AF anisotropy and exchange coupling. The resulting angular behavior demonstrates the key role of the size distribution and temperature in the magnetic response of nanoparticles.Comment: Revised arguments in Introduction and last sectio

Observation of the spin Peltier effect

We report the observation of the spin Peltier effect (SPE) in the ferrimagnetic insulator Yttrium Iron Garnet (YIG), i.e. a heat current generated by a spin current flowing through a Platinum (Pt)|YIG interface. The effect can be explained by the spin torque that transforms the spin current in the Pt into a magnon current in the YIG. Via magnon-phonon interactions the magnetic fluctuations modulate the phonon temperature that is detected by a thermopile close to the interface. By finite-element modelling we verify the reciprocity between the spin Peltier and spin Seebeck effect. The observed strong coupling between thermal magnons and phonons in YIG is attractive for nanoscale cooling techniques.Comment: 5 pages, 3 figures, 4 pages supplementary information, 4 supplementary figure