| 1. |
- Schild, R., et al.
(author)
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Disparities in treatment and outcome of kidney replacement therapy in children with comorbidities: an ESPN/ERA Registry study
- 2023
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In: Clinical Kidney Journal. - : Oxford University Press (OUP). - 2048-8505 .- 2048-8513. ; 16:4, s. 745-755
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Journal article (peer-reviewed)abstract
- Background Data on comorbidities in children on kidney replacement therapy (KRT) are scarce. Considering their high relevance for prognosis and treatment, this study aims to analyse the prevalence and implications of comorbidities in European children on KRT. Methods We included data from patients <20 years of age when commencing KRT from 2007 to 2017 from 22 European countries within the European Society of Paediatric Nephrology/European Renal Association Registry. Differences between patients with and without comorbidities in access to kidney transplantation (KT) and patient and graft survival were estimated using Cox regression. Results Comorbidities were present in 33% of the 4127 children commencing KRT and the prevalence has steadily increased by 5% annually since 2007. Comorbidities were most frequent in high-income countries (43% versus 24% in low-income countries and 33% in middle-income countries). Patients with comorbidities had a lower access to transplantation {adjusted hazard ratio [aHR] 0.67 [95% confidence interval (CI) 0.61-0.74]} and a higher risk of death [aHR 1.79 (95% CI 1.38-2.32)]. The increased mortality was only seen in dialysis patients [aHR 1.60 (95% CI 1.21-2.13)], and not after KT. For both outcomes, the impact of comorbidities was stronger in low-income countries. Graft survival was not affected by the presence of comorbidities [aHR for 5-year graft failure 1.18 (95% CI 0.84-1.65)]. Conclusions Comorbidities have become more frequent in children on KRT and reduce their access to transplantation and survival, especially when remaining on dialysis. KT should be considered as an option in all paediatric KRT patients and efforts should be made to identify modifiable barriers to KT for children with comorbidities. Lay Summary Kidney transplantation (KT) is considered the optimal treatment for children who suffer from permanent kidney failure, because it leads to a lower mortality and higher quality of life compared with dialysis. Children on dialysis frequently suffer from diseases of other organs (comorbidities) that can directly lower their life expectancy and could potentially represent a barrier for transplantation, posing an additional disease burden for these children. In this study we looked at data from a large multinational registry for children with kidney failure who require kidney replacement. Using these data, we studied whether these children suffered from comorbidities and whether these impact their life expectancy or their access to KT. We found that more and more children with kidney failure suffer from comorbidities when starting kidney replacement therapy. We also found that these children have a lower access to KT and a higher mortality on dialysis compared with children without comorbidities, especially in low-income countries. After KT, children with comorbidities have a similar mortality and graft survival compared with children without comorbidities. We concluded that reduced access to a kidney transplant might represent a modifiable barrier to KT in children with comorbidities, especially in low-resource countries. We suggest that children with comorbidities in need for kidney replacement therapy should be rapidly evaluated for eligibility for KT.
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| 2. |
- Bonetti, Stefano, et al.
(author)
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Power and linewidth of propagating and localized modes in nanocontact spin-torque oscillators
- 2012
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 85:17, s. 174427-
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Journal article (peer-reviewed)abstract
- The integrated power and linewidth of a propagating and a self-localized spin-wave mode excited by spin-polarized current in an obliquely magnetized magnetic nanocontact are studied experimentally as functions of the angle theta(e) between the external bias magnetic field and the nanocontact plane. It is found that the power of the propagating mode increases monotonically with theta(e), while the power of the self-localized mode has a broad maximum near theta(e) = 40 degrees and exponentially vanishes near the critical angle theta(e) = 58 degrees, at which the localized mode disappears. The linewidth of the propagating mode in the interval of angles 58 degrees < theta(e) < 90 degrees, where only this mode is excited, is adequately described by the existing theory, while in the angular interval where both modes can exist the observed linewidth of both modes is substantially broadened due to the telegraph switching between the modes. Numerical simulations and an approximate analytical model give a good semiquantitative description of the observed results.
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| 3. |
- Consolo, G., et al.
(author)
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Non-stationary excitation of two localized spin-wave modes in a nano-contact spin torque oscillator
- 2013
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 114:15, s. 153906-
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Journal article (peer-reviewed)abstract
- We measure and simulate micromagnetically a framework based upon a nano-contact spin torque oscillator where two distinct localized evanescent spin-wave modes can be detected. The resulting frequency spectrum is composed by two peaks, corresponding to the excited modes, which lie below the ferromagnetic resonance frequency, and a low-frequency tail, which we attribute to the non-stationary switching between these modes. By using Fourier, wavelet, and Hilbert-Huang transforms, we investigate the properties of these modes in time and spatial domains, together with their spatial distribution. The existence of an additional localized mode (which was neither predicted by theory nor by previous numerical and experimental findings) has to be attributed to the large influence of the current-induced Oersted field strength which, in the present setup, is of the same order of magnitude as the external field. As a further consequence, the excited spin-waves, contrarily to what usually assumed, do not possess cylindrical symmetry: the Oersted field induces these modes to be excited at the two opposite sides of the region beneath the nano-contact.
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