Achievements, priorities and strategies in pediatric nephrology in Europe: need for unifying approaches or acceptance of differences?

Background: There is a lack of information on the current healthcare systems for children with kidney diseases across Europe. The aim of this study was to explore the different national approaches to the organization and delivery of pediatric nephrology services within Europe.

Methods: In 2020, the European society for Paediatric Nephrology (ESPN) conducted a cross-sectional survey to identify the existing pediatric nephrology healthcare systems in 48 European countries covering a population of more than 200 million children.

Correction: Stämmler et al. Estimating Glomerular Filtration Rate from Serum Myo-Inositol, Valine, Creatinine and Cystatin C. 2021, , 2291.

In the original publication [...

Unlocking the potential of information flow: Maximizing free-energy transduction in a model of an autonomous rotary molecular motor.

Molecular motors fulfill critical functions within all living beings. Understanding their underlying working principles is therefore of great interest. Here we develop a simple model inspired by the two-component biomolecular motor F_{o}-F_{1} ATP synthase.

Diversity of kidney care referral pathways in national child health systems of 48 European countries.

Background: Primary, secondary and tertiary healthcare services in Europe create complex networks covering pediatric subspecialties, sociology, economics and politics. Two surveys of the European Society for Paediatric Nephrology (ESPN) in 1998 and 2017 revealed substantial disparities of kidney care among European countries. The purpose of the third ESPN survey is to further identify national differences in the conceptualization and organization of European pediatric kidney health care pathways during and outside normal working hours.

Information Engine in a Nonequilibrium Bath.

Information engines can convert thermal fluctuations of a bath at temperature T into work at rates of order k_{B}T per relaxation time of the system. We show experimentally that such engines, when in contact with a bath that is out of equilibrium, can extract much more work. We place a heavy, micron-scale bead in a harmonic potential that ratchets up to capture favorable fluctuations.

Bayesian Information Engine that Optimally Exploits Noisy Measurements.

We have experimentally realized an information engine consisting of an optically trapped, heavy bead in water. The device raises the trap center after a favorable "up" thermal fluctuation, thereby increasing the bead's average gravitational potential energy. In the presence of measurement noise, poor feedback decisions degrade its performance; below a critical signal-to-noise ratio, the engine shows a phase transition and cannot store any gravitational energy.

Analytical Validation of GFR: A Blood-Based Multiple Biomarker Assay for Accurate Estimation of Glomerular Filtration Rate.

Accurate and precise monitoring of kidney function is critical for a timely and reliable diagnosis of chronic kidney disease (CKD). The determination of kidney function usually involves the estimation of the glomerular filtration rate (eGFR). We recently reported the clinical performance of a new eGFR equation (GFR) based on the nuclear magnetic resonance (NMR) measurement of serum myo-inositol, valine, and creatinine, in addition to the immunoturbidometric quantification of serum cystatin C, age and sex.

Effects of Microstructure Modification by Friction Surfacing on Wear Behavior of Al Alloys with Different Si Contents.

In this work, Al alloys with 6.6%, 10.4%, and 14.

Estimating Glomerular Filtration Rate from Serum Myo-Inositol, Valine, Creatinine and Cystatin C.

Assessment of renal function relies on the estimation of the glomerular filtration rate (eGFR). Existing eGFR equations, usually based on serum levels of creatinine and/or cystatin C, are not uniformly accurate across patient populations. In the present study, we expanded a recent proof-of-concept approach to optimize an eGFR equation targeting the adult population with and without chronic kidney disease (CKD), based on a nuclear magnetic resonance spectroscopy (NMR) derived 'metabolite constellation' (GFR).

Maximal fluctuation exploitation in Gaussian information engines.

Understanding the connections between information and thermodynamics has been among the most visible applications of stochastic thermodynamics. While recent theoretical advances have established that the second law of thermodynamics sets limits on information-to-energy conversion, it is currently unclear to what extent real systems can achieve the predicted theoretical limits. Using a simple model of an information engine that has recently been experimentally implemented, we explore the limits of information-to-energy conversion when an information engine's benefit is limited to output energy that can be stored.

Maximizing power and velocity of an information engine.

Information-driven engines that rectify thermal fluctuations are a modern realization of the Maxwell-demon thought experiment. We introduce a simple design based on a heavy colloidal particle, held by an optical trap and immersed in water. Using a carefully designed feedback loop, our experimental realization of an "information ratchet" takes advantage of favorable "up" fluctuations to lift a weight against gravity, storing potential energy without doing external work.

The implications of complexity, systems thinking and philosophy for pediatricians.

National service systems in child healthcare are characterized by diversity and complexity. Primary, secondary, tertiary and quaternary healthcare services create complex networks covering pediatric subspecialties, psychology, sociology, economics and politics. Can pediatrics exist without philosophy? Does the absence of integrating philosophical perspectives during conceptualization of pediatric care contribute to deficiencies in the service systems structuring child healthcare? Philosophy offers new ways of complex systems thinking in scientific and clinical pediatrics.

Free-energy transduction within autonomous systems.

The excess work required to drive a stochastic system out of thermodynamic equilibrium through a time-dependent external perturbation is directly related to the amount of entropy produced during the driving process, allowing excess work and entropy production to be used interchangeably to quantify dissipation. Given the common intuition of biological molecular machines as internally communicating work between components, it is tempting to extend this correspondence to the driving of one component of an autonomous system by another; however, no such relation between the internal excess work and entropy production exists. Here we introduce the "transduced additional free-energy rate" between strongly coupled subsystems of an autonomous system, which is analogous to the excess power in systems driven by an external control parameter that receives no feedback from the system.

Serum Myo-Inositol, Dimethyl Sulfone, and Valine in Combination with Creatinine Allow Accurate Assessment of Renal Insufficiency-A Proof of Concept.

Evaluation of renal dysfunction includes estimation of glomerular filtration rate (eGFR) as the initial step and subsequent laboratory testing. We hypothesized that combined analysis of serum creatinine, myo-inositol, dimethyl sulfone, and valine would allow both assessment of renal dysfunction and precise GFR estimation. Bio-banked sera were analyzed using nuclear magnetic resonance spectroscopy (NMR).

Optimal finite-time bit erasure under full control.

We study the finite-time erasure of a one-bit memory consisting of a one-dimensional double-well potential, with each well encoding a memory macrostate. We focus on setups that provide full control over the form of the potential-energy landscape and derive protocols that minimize the average work needed to erase the bit over a fixed amount of time. We allow for cases where only some of the information encoded in the bit is erased.

Finite-Time Landauer Principle.

We study the thermodynamic cost associated with the erasure of one bit of information over a finite amount of time. We present a general framework for minimizing the average work required when full control of a system's microstates is possible. In addition to exact numerical results, we find simple bounds proportional to the variance of the microscopic distribution associated with the state of the bit.

The European Society for Paediatric Nephrology study of pediatric renal care in Europe: comparative analysis 1998-2017.

Background: In 1998, a survey of the European Society for Paediatric Nephrology (ESPN) revealed substantial disparities in pediatric renal care among European countries. Therefore, ESPN aimed at harmonizing renal care in all European countries in the following 20 years. In 2017, we conducted a survey to evaluate the current status of renal health policies for children in Europe.

A within-subject experiment of item format effects on early primary students' language, reading, and numeracy assessment results.

Standardized testing is ubiquitous in educational assessment, but questions have been raised about the extent to which these test scores accurately reflect students' genuine knowledge and skills. To more rigorously investigate this issue, the current study employed a within-subject experimental design to examine item format effects on primary school students' standardized assessment results in literacy, reading comprehension, and numeracy. Eighty-nine Grade 3 students (ages 8-9 years) completed tests that varied only in item format: multiple choice; open-ended; error detection and correction; explain; and, for numeracy questions, low literacy.

Approximating microswimmer dynamics by active Brownian motion: Energetics and efficiency.

We consider the dynamics of a microswimmer and show that they can be approximated by active Brownian motion. The swimmer is modeled by coupled overdamped Langevin equations with periodic driving. We compare the energy dissipation of the real swimmer to that of the active Brownian motion model, finding that the latter can massively underestimate the complete dissipation.