Treatment and long-term outcome in primary nephrogenic diabetes insipidus

Background: Primary nephrogenic diabetes insipidus (NDI) is a rare disorder and little is known about treatment practices and long-term outcome. Methods: Paediatric and adult nephrologists contacted through European professional organizations entered data in an online form. Results: Data were collected on 315 patients (22 countries, male 84%, adults 35%). Mutation testing had been performed in 270 (86%); pathogenic variants were identified in 258 (96%). The median (range) age at diagnosis was 0.6 (0.0–60) years and at last follow-up 14.0 (0.1–70) years. In adults, height was normal with a mean (standard deviation) score of −0.39 (±1.0), yet there was increased prevalence of obesity (body mass index >30 kg/m2; 41% versus 16% European average; P < 0.001). There was also increased prevalence of chronic kidney disease (CKD) Stage ≥2 in children (32%) and adults (48%). Evidence of flow uropathy was present in 38%. A higher proportion of children than adults (85% versus 54%; P < 0.001) received medications to reduce urine output. Patients ≥25 years were less likely to have a university degree than the European average (21% versus 35%; P = 0.003) but full-time employment was similar. Mental health problems, predominantly attention-deficit hyperactivity disorder (16%), were reported in 36% of patients. Conclusion: This large NDI cohort shows an overall favourable outcome with normal adult height and only mild to moderate CKD in most. Yet, while full-time employment was similar to the European average, educational achievement was lower, and more than half had urological and/or mental health problems

Proceedings of the 24th Paediatric Rheumatology European Society Congress: Part three

From Springer Nature via Jisc Publications Router.Publication status: PublishedHistory: collection 2017-09, epub 2017-09-0

Flow investigation in centrifugal compressor vaneless and vaned diffusers

Available from British Library Document Supply Centre-DSC:DXN003634 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Interface stabilization in two-layer channel flow by surface heating or cooling

The linear stability of plane Poiseuille flow of two immiscible Newtonian liquids in a differentially heated channel is considered. The equations of motion and energy are fully coupled via temperature-dependent fluid-viscosity coefficients. A long-wave asymptotic formulation of the stability problem is presented together with numerical results for disturbances of arbitrary wavelength. Two combinations of immiscible liquids are analyzed: silicone/water and oil/water (water at the bottom layer in both cases). It is shown that an imposed wall temperature difference can be stabilizing or destabilizing depending on the disturbance wavenumber and layer thickness ratio. Interfacial tension has a stabilizing effect on the interface. Stabilizing influence of interfacial tension is observed at intermediate and large wavenumbers. Most importantly, for certain ranges of the controlling dimensionless parameters, stable interfaces at all disturbance wavelengths can be attained

Formulation and computational issues for stability of two-layer inelastic fluids

A numerical solution technique based on the Chebyshev pseudospectral method is presented for solving boundary value and generalized complex eigenvalue problems which are valid over connected domains coupled through interfacial boundary conditions. As an example, the eigenvalue problem that describes the linear stability of two superposed inelastic Carreau-Yasuda fluids in plane Poiseuille flow is considered. Collocation points are formed by following two different approaches and it is shown that the accuracy of the results are highly dependent on the choice of collocation points. Therefore, in the success of pseudospectral method, a proper selection of collocation points for boundary value and eigenvalue problems is very crucial. © 2000 Elsevier Science Ltd. All rights reserved

Stability of a Non-Newtonian fluid in a channel with heat transfer

The Fluids Engineering Division, ASME2003 ASME International Mechanical Engineering Congress --15 November 2003 through 21 November 2003 -- Washington, DC. --In this paper the linear stability of plane Poiseuille flow is studied for a non-Newtonian liquid having an exponential viscosity-temperature dependence. Non-Newtonian behavior of the fluid is modeled through Carreau rheological equation. Channel walls are kept at constant but different temperatures. Steady base flow equations and equations describing the evolution of small, two-dimensional disturbances are derived and solved numerically. The stability problem is formulated as an eigenvalue problem for a set of ordinary differential equations. Discritization is performed using a pseudospectral technique based on Chebyshev polynomials expansions. The resulting generalized matrix eigenvalue problem is solved using the QZ algorithm. The results presenting the influence of temperature and shear-rate dependent viscosity on the stability are given in the form of marginal stability curves for a wide range of flow and fluid dimensionless parameters, including channel wall temperature difference ?T¯, material time constant ?, and power-law index n

Effect of viscosity models on the stability of a non-Newtonian fluid in a channel with heat transfer

This study investigates the effect of temperature-dependent and shear-thinning viscosity of a non-Newtonian fluid on the stability of a channel flow. Exponential dependence of viscosity on temperature is modeled through Arrhenius law and Nahme Law. Non-Newtonian behaviour of the fluid is modeled according to the Carreau rheological equation. Channel walls are kept at constant but different temperatures. Steady base flow governing boundary value problem and stability governing eigenvalue problem are solved using a pseudospectral method based on Chebyshev polynomials. Results are presented in the form of marginal stability curves. It is found that fluids obeying the Arrhenius law are more stable than those of Nahme law if both models are used on the same temperature-sensitive viscosity, reference viscosity and temperature. © 2001 Elsevier Science Ltd

Viscous heating effects on the linear stability of Poiseuille flow of an inelastic fluid

In this paper, the effect of viscous heating on the stability of a non-Newtonian fluid flowing between two parallel plates under the effect of a constant pressure gradient is investigated. The viscosity of the fluid depends on both temperature and shear rate. Exponential dependence of viscosity on temperature is modeled through Arrhenius law. Non-Newtonian behavior of the fluid is modeled according to the Carreau rheological model. Motion and energy balance equations that govern the base flow and the stability of the flow are coupled and the solution to the problem is found iteratively using a pseudospectral method based on the Chebyshev polynomials. In the presence of viscous heating, the effect of activation energy parameter, Prandtl and Brinkman numbers, material time and power-law constants on the stability of the flow is presented in terms of neutral stability curves. © 2005 Elsevier B.V. All rights reserved

Nonisothermal channel flow of a non-newtonian fluid with viscous heating

This study investigates the pressure gradient-flow rate relationship for steady-state nonisothermal pressure-driven flow of a non-Newtonian fluid in a channel including the effect of viscous heating. The viscosity of the fluid depends on both temperature and shear-rate. Exponential dependence of viscosity on temperature is modeled through Arrhenius law. Non-Newtonian behaviour of the fluid is modeled according to the Carreau rheological equation. Flow governing motion and energy balance equations are coupled and the solution of this non-linear boundary value problem is found iteratively using a pseudospectral method based on Chebyshev polynomials. The effect of activation energy parameter and Brinkman number, as well as the power-law index and material time constant on the flow is studied. It is found that while the pressure gradient-flow rate graph is monotonic for certain ranges of flow controlling parameters, there is a large jump in the graph under certain values of these parameters. © 2002 Elsevier Science Ltd