58 research outputs found
Impact of food supplements on hemoglobin, iron status, and inflammation in children with moderate acute malnutrition: a 2 × 2 × 3 factorial randomized trial in Burkina Faso.
Background: Children with moderate acute malnutrition (MAM) are treated with lipid-based nutrient supplements (LNSs) or corn-soy blends (CSBs) but little is known about the impact of these supplements on hemoglobin, iron status, and inflammation. Objective: The objective of this study was to investigate the impact of supplementary foods for treatment of MAM on hemoglobin, iron status, inflammation, and malaria. Design: A randomized 2 × 2 × 3 factorial trial was conducted in Burkina Faso. Children aged 6-23 mo with MAM received 500 kcal/d as LNS or CSB, containing either dehulled soy (DS) or soy isolate (SI) and different quantities of dry skimmed milk (0%, 20% or 50% of total protein) for 12 wk. The trial was double-blind with regard to quality of soy and quantity of milk, but not matrix (CSB compared to LNS). Hemoglobin, serum ferritin (SF), serum soluble transferrin receptor (sTfR), serum C-reactive protein (CRP), serum α1-acid glycoprotein (AGP), and malaria antigens were measured at inclusion and after supplementation. Results: Between September 2013 and August 2014, 1609 children were enrolled. Among these, 61 (3.8%) were lost to follow-up. During the 12-wk supplementation period, prevalence of anemia, low SF adjusted for inflammation (SFAI), elevated sTfR, and iron-deficiency anemia decreased by 16.9, 8.7, 12.6 and 10.5 percentage points. Children who received LNS compared to CSB had higher hemoglobin (2 g/L; 95% CI: 1, 4 g/L), SFAI (4.2 µg/L; 95% CI: 2.9, 5.5 µg/L), and CRP (0.8 mg/L; 95% CI: 0.4, 1.2 mg/L) and lower sTfR (-0.9 mg/L, 95% CI: -1.3, -0.6 mg/L) after the intervention. Replacing DS with SI or increasing milk content did not affect hemoglobin, SFAI, sTfR, or CRP. Conclusion: Supplementation with LNS compared to CSB led to better hemoglobin and iron status, but overall prevalence of anemia remained high. The higher concentrations of acute-phase proteins in children who received LNSs requires further investigation. This trial was registered at www.controlled-trials.com as ISRCTN42569496
Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV
Peer reviewe
Stability of weak solutions to parabolic problems with nonstandard growth and cross–diffusion
We study the stability of a unique weak solution to certain parabolic systems with nonstandard growth condition, which are additionally dependent on a cross-diffusion term. More precisely, we show that two unique weak solutions of the considered system with different initial values are controlled by their initial values
Bifurcation Analysis of a Certain Hodgkin-Huxley Model Depending on Multiple Bifurcation Parameters
In this paper, we study the dynamics of a certain Hodgkin-Huxley model describing the action potential (AP) of a cardiac muscle cell for a better understanding of the occurrence of a special type of cardiac arrhythmia, the so-called early afterdepolarisations (EADs). EADs are pathological voltage oscillations during the repolarisation or plateau phase of cardiac APs. They are considered as potential precursors to cardiac arrhythmia and are often associated with deficiencies in potassium currents or enhancements in the calcium or sodium currents, e.g., induced by ion channel diseases, drugs or stress. Our study is focused on the enhancement in the calcium current to identify regions, where EADs related to enhanced calcium current appear. To this aim, we study the dynamics of the model using bifurcation theory and numerical bifurcation analysis. Furthermore, we investigate the interaction of the potassium and calcium current. It turns out that a suitable increasing of the potassium current adjusted the EADs related to an enhanced calcium current. Thus, one can use our result to balance the EADs in the sense that an enhancement in the potassium currents may compensate the effect of enhanced calcium currents
Early afterdepolarisations induced by an enhancement in the calcium current
Excitable biological cells, such as cardiac muscle cells, can exhibit complex patterns of oscillations such as spiking and bursting. Moreover, it is well known that an enhancement in calcium currents may yield certain kind of cardiac arrhythmia, so-called early afterdepolarisations (EADs). The presence of EADs strongly correlates with the onset of dangerous cardiac arrhythmia. In this paper we study mathematically and numerically the dynamics of a cardiac muscle cell with respect to the calcium current by investigating a simplistic system of differential equations. For the study of this phenomena, we use bifurcation theory, numerical bifurcation analysis, geometric singular perturbation theory and computational methods to investigate a nonlinear multiple time scales system. It will turn out that EADs related to an enhanced calcium current are canard–induced and that we have to combine these theories to derive a better understanding of the dynamics behind EADs. Moreover, a suitable time scale separation argument determines the important and sensitive system parameters which are related to the occurrence of EADs
Existence and uniqueness of weak solutions to parabolic problems with nonstandard growth and cross diffusion
Existence of weak solutions to a certain homogeneous parabolic Neumann problem involving variable exponents and cross-diffusion
This paper deals with a homogeneous Neumann problem of a nonlinear diffusion system involving variable exponents dependent on spatial and time variables and cross-diffusion terms. We prove the existence of weak solutions using Galerkin’s approximation and we derive suitable energy estimates. To this end, we establish the needed Poincaré type inequality for variable exponents related to the Neumann boundary problem. Furthermore, we show that the investigated problem possesses a unique weak solution and satisfies a stability estimate, provided some additional assumptions are fulfilled. In addition, we show under which conditions the solution is nonnegative
Existence of weak solutions to the Keller-Segel chemotaxis system with additional cross-diffusion
In this paper, we consider the Keller–Segel chemotaxis system with additional cross-diffusion term in the second equation. This system is consisting of a fully nonlinear reaction–diffusion equations with additional cross-diffusion. We establish the existence of weak solutions to the considered system by using Schauder’s fixed point theorem, a priori energy estimates and the compactness results
Dynamics of a neuron-glia system: the occurrence of seizures and the influence of electroconvulsive stimuli
In this paper, we investigate the dynamics of a neuron–glia cell system and the underlying mechanism for the occurrence of seizures. For our mathematical and numerical investigation of the cell model we will use bifurcation analysis and some computational methods. It turns out that an increase of the potassium concentration in the reservoir is one trigger for seizures and is related to a torus bifurcation. In addition, we will study potassium dynamics of the model by considering a reduced version and we will show how both mechanisms are linked to each other. Moreover, the reduction of the potassium leak current will also induce seizures. Our study will show that an enhancement of the extracellular potassium concentration, which influences the Nernst potential of the potassium current, may lead to seizures. Furthermore, we will show that an external forcing term (e.g. electroshocks as unidirectional rectangular pulses also known as electroconvulsive therapy) will establish seizures similar to the unforced system with the increased extracellular potassium concentration. To this end, we describe the unidirectional rectangular pulses as an autonomous system of ordinary differential equations. These approaches will explain the appearance of seizures in the cellular model. Moreover, seizures, as they are measured by electroencephalography (EEG), spread on the macro–scale (cm). Therefore, we extend the cell model with a suitable homogenised monodomain model, propose a set of (numerical) experiment to complement the bifurcation analysis performed on the single–cell model. Based on these experiments, we introduce a bidomain model for a more realistic modelling of white and grey matter of the brain. Performing similar (numerical) experiment as for the monodomain model leads to a suitable comparison of both models. The individual cell model, with its seizures explained in terms of a torus bifurcation, extends directly to corresponding results in both the monodomain and bidomain models where the neural firing spreads almost synchronous through the domain as fast traveling waves, for physiologically relevant paramenters
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