RICORS2040 : The need for collaborative research in chronic kidney disease

Chronic kidney disease (CKD) is a silent and poorly known killer. The current concept of CKD is relatively young and uptake by the public, physicians and health authorities is not widespread. Physicians still confuse CKD with chronic kidney insufficiency or failure. For the wider public and health authorities, CKD evokes kidney replacement therapy (KRT). In Spain, the prevalence of KRT is 0.13%. Thus health authorities may consider CKD a non-issue: very few persons eventually need KRT and, for those in whom kidneys fail, the problem is 'solved' by dialysis or kidney transplantation. However, KRT is the tip of the iceberg in the burden of CKD. The main burden of CKD is accelerated ageing and premature death. The cut-off points for kidney function and kidney damage indexes that define CKD also mark an increased risk for all-cause premature death. CKD is the most prevalent risk factor for lethal coronavirus disease 2019 (COVID-19) and the factor that most increases the risk of death in COVID-19, after old age. Men and women undergoing KRT still have an annual mortality that is 10- to 100-fold higher than similar-age peers, and life expectancy is shortened by ~40 years for young persons on dialysis and by 15 years for young persons with a functioning kidney graft. CKD is expected to become the fifth greatest global cause of death by 2040 and the second greatest cause of death in Spain before the end of the century, a time when one in four Spaniards will have CKD. However, by 2022, CKD will become the only top-15 global predicted cause of death that is not supported by a dedicated well-funded Centres for Biomedical Research (CIBER) network structure in Spain. Realizing the underestimation of the CKD burden of disease by health authorities, the Decade of the Kidney initiative for 2020-2030 was launched by the American Association of Kidney Patients and the European Kidney Health Alliance. Leading Spanish kidney researchers grouped in the kidney collaborative research network Red de Investigación Renal have now applied for the Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS) call for collaborative research in Spain with the support of the Spanish Society of Nephrology, Federación Nacional de Asociaciones para la Lucha Contra las Enfermedades del Riñón and ONT: RICORS2040 aims to prevent the dire predictions for the global 2040 burden of CKD from becoming true

A method to limit uncertainties in aerosol properties determined from comparative measurements

© 2015 Elsevier Ltd. Certain types of aerosol measurements require an experimental set up including two or more routes through which the particles are made to flow alternatively. Indeed, this appears to be critical to limit uncertainties in aerosol properties determined from comparative measurements. Typical examples are the comparison of the performance of different instruments and the measurement of particle filtration efficiency. Except for the presence of the test units (e.g. the instruments or devices to be compared) it is commonly accepted that the two routes must be identical: they should contain the same type and number of tubes, valves, junctions, bends, connectors, etc. For nanometer-sized particles undergoing substantial diffusion losses, the lack of perfect symmetry between the two routes induces discrepancies in measurements performed in both lines. This article provides a general methodology to avoid or reduce the errors arising from these possible asymmetries. The method consists in making two measurements, one with the given setup, the other with an alternative set up in which the test units have been exchanged. The correct result (e.g. filtration efficiency) is the geometric mean of the results obtained with the two alternative setups. The proposed methodology may seem tedious and time consuming, but doing so, the experimental measurement is not affected neither by possible errors due to a test aerosol changing with time nor by the possible asymmetry of the line accessories (valves, T[U+05F3]s, connections, etc.).The work was partly supported by Spain׳s Ministry of Economy and Competitiveness under Grant number MINECOR13/P73.Peer Reviewe

Atmospheric pressure plasmas for aerosols processes in materials and environment

International audienceThe paper highlights applications of some atmospheric pressure plasmas (dc-corona, streamer and spark and ac-Dielectric Barrier Discharges) to aerosol processes for Materials and Environment (filtration, diagnostics). The production of vapor i.e. condensable gaseous species, leads to nano-sized particles by physical and chemical routes of nucleation in these AP plasmas: (i) when dc streamer and spark filamentary discharges as well as ac filamentary dielectric barrier discharges interact with metal or dielectric surfaces, and (ii) when discharges induce reactions with gaseous precursors in volume. It is shown how composition, size and structure of primary nano-particles are related to plasma parameters (energy, number per unit surface and time and thermal gradients). Then the growth by coagulation controls the final size of agglomerates versus plasma parameters and transit time in and after the plasma. Charging and electro-thermal collection are depicted to account for the related potential applications of controlled kinematics of charged aerosol

Determination of the Mean Mobility of Aerosol Nanoparticles Classified by Differential Mobility Analyzers

© 2014 American Association for Aerosol Research. MonteCarlo simulations of diffusive particle trajectories, as well as Stolzenburg's model calculations, have shown that the mean mobility of the particles classified by a differential mobility analyzer (DMA) at a given applied voltage may differ from the theoretical one inferred from the Knutson-Whitby equation if the particles are withdrawn from the tails of the particle mobility distribution. In this case, the true mean mobility, defined as the mean mobility of the particles classified at the specified voltage, can be precisely measured by a second DMA operating in series with the first one (tandem DMA). However, if particles are extracted from the central part of the distribution, their mobility can be correctly measured with a single DMA. Besides showing the importance of the usage of the tandem DMA technique for accurate measurements of mobility, this article provides an analytical expression which, if the mobility distribution of the polydisperse aerosol fed to the DMA is known, allows an accurate estimation of the true (mean) mobility of the classified particles.Peer Reviewe

Anumericalstudyoftheinfluenceofion–aerosolmixingonunipolarcharging

A theoreticalinvestigationhasbeencarriedouttoexaminetheeffectoftheinitialion–aerosol mixing stateontheresultingchargedfraction(extrinsicchargingefficiency)ofultrafinepar- ticles inacirculartubeunderlaminarflowconditions.Particleandionlosstothewallsby diffusion andelectrostaticdispersionweretakenintoaccountinthecalculations.Fourdif- ferent mixingstateswereconsideredattheinletsectionofthechargingtube:(I)uniform mixing ofionsandneutralparticles;(II)acoreofionssurroundedbyanenvelopeofneutral particles; (III)acoreofneutralparticlessurroundedbyanenvelopeofions;and(IV)theinlet section splitupintotwocircularsegments,onecontainingneutralparticlesalone,theother only ions.Thenumericalresultsshowthattheextrinsicchargingefficiencystronglydepends on theinitialmixingstate,themaximumefficiencybeingattainedformixingstateII,astate which canbeeasilyrealizedinpracticebyinjectingionsandparticlesintothechargerthrough two coaxialcylinders.TheworstcaseisthatofmixingstateIII,thereverseofII,inwhichthe neutral particlesareinjectedthroughtheinnercylinder,andtheunipolarionsthroughthe annular spacebetweentheinjectiontubes.Themainreasonunderlyingtheobservedbehavior is thestrongdependencyoftheionslossratetothewallontheirinitialspatialdistributionSpain'sMinisteriodeCienciaeInnovaciónundergrantDPI2008-06199Peer reviewe

Electrical properties of airborne nanoparticles produced by a commercial spark-discharge generator

International audiencenanoparticle generator based on the principle of electrical discharge (PALAS GFG-1000) was used to produce nanoparticles of different chemical natures. The fractions of electrically neutral particles were then measured by means of a Spectromètre de Mobilité Electrique Circulaire (SMEC, i.e. radial-flow mobility analyzer) for different operating conditions. The experimental results were compared with the theoretical values calculated from the Fuchs extended charge equilibrium model for spherical particles and agglomerates. For the smallest particles (below 20 nm), the deviations observed remain below 10%, and tend towards 20% for larger particles (over 35 nm)

Deposition of ultrafine aerosol particles on wire screen by simultaneous diffusion and image force

This paper presents the results of an experimental investigation on the deposition of multiply charged particles on wire screens by the combined mechanisms of diffusion and image force. Experiments were performed with particles having diameters between 25 and 65 nm (transition regime), carrying 0, +1, +2 or +3 elementary charges, and using three different flow rates, two types of wire screen, and two types of test aerosol. The single fiber efficiencies for the mechanisms of image force, IM, and diffusion, D, are of the same order of magnitude and, furthermore, they are both much smaller than one. Under these conditions, the total capture efficiency can be approximated as the sum of the efficiencies by diffusion and image force deposition. Theoretically, IM is proportional to the square root of a dimensionless number, KIM, which includes all the relevant parameters cited above (i.e., particle size and charge, aerosol flow rate and screen geometry). The available correlations for IM, obtained from experiments with particles carrying a large number of elementary charges (KIM >10−5), predict that image force should not have any effect in the case of the small particles with very few number of charges that we have tested in our experiments (in our experimentation, KIM ranged between 10−7 and 10−5). Our results, the only ones available to date for this particle size range, show that there is indeed a clear, measurable effect. Although our experimental results are best fitted by the correlation IM = 29.7K0.59 IM , it is shown that the expression IM = 9.7√KIM, which is in agreement with the theoretical 1/2 exponent for KIM, also reproduces reasonably well the measured valuesThis work was partly supported by Ministerio de Educación y Ciencia under Grant CTM2006-02600/TECNO.Peer reviewe