2,145 research outputs found
Probability of the emergence of helical precipitation patterns in the wake of reaction-diffusion fronts
Helical and helicoidal precipitation patterns emerging in the wake of
reaction-diffusion fronts are studied. In our experiments, these chiral
structures arise with well-defined probabilities P_H controlled by conditions
such as e.g., the initial concentration of the reagents. We develop a model
which describes the observed experimental trends. The results suggest that P_H
is determined by a delicate interplay among the time and length scales related
to the front and to the unstable precipitation modes and, furthermore, the
noise amplitude also plays a quantifiable role.Comment: 7 pages, 5 composite figure
Early brain activity : Translations between bedside and laboratory
Neural activity is both a driver of brain development and a readout of developmental processes. Changes in neuronal activity are therefore both the cause and consequence of neurodevelopmental compromises. Here, we review the assessment of neuronal activities in both preclinical models and clinical situations. We focus on issues that require urgent translational research, the challenges and bottlenecks preventing translation of biomedical research into new clinical diagnostics or treatments, and possibilities to overcome these barriers. The key questions are (i) what can be measured in clinical settings versus animal experiments, (ii) how do measurements relate to particular stages of development, and (iii) how can we balance practical and ethical realities with methodological compromises in measurements and treatments.Peer reviewe
The effects of delay on the HKB model of human motor coordination
Understanding human motor coordination holds the promise of developing
diagnostic methods for mental illnesses such as schizophrenia. In this paper,
we analyse the celebrated Haken-Kelso-Bunz (HKB) model, describing the dynamics
of bimanual coordination, in the presence of delay. We study the linear
dynamics, stability, nonlinear behaviour and bifurcations of this model by both
theoretical and numerical analysis. We calculate in-phase and anti-phase limit
cycles as well as quasi-periodic solutions via double Hopf bifurcation analysis
and centre manifold reduction. Moreover, we uncover further details on the
global dynamic behaviour by numerical continuation, including the occurrence of
limit cycles in phase quadrature and 1-1 locking of quasi-periodic solutions.Comment: Submitted to the SIAM Journal on Applied Dynamical Systems. 27 pages,
8 figure
Evaluation of Microarray Preprocessing Algorithms Based on Concordance with RT-PCR in Clinical Samples
BACKGROUND
Several preprocessing algorithms for Affymetrix gene expression microarrays have been developed, and their performance on spike-in data sets has been evaluated previously. However, a comprehensive comparison of preprocessing algorithms on samples taken under research conditions has not been performed.
METHODOLOGY/PRINCIPAL FINDINGS
We used TaqMan RT-PCR arrays as a reference to evaluate the accuracy of expression values from Affymetrix microarrays in two experimental data sets: one comprising 84 genes in 36 colon biopsies, and the other comprising 75 genes in 29 cancer cell lines. We evaluated consistency using the Pearson correlation between measurements obtained on the two platforms. Also, we introduce the log-ratio discrepancy as a more relevant measure of discordance between gene expression platforms. Of nine preprocessing algorithms tested, PLIER+16 produced expression values that were most consistent with RT-PCR measurements, although the difference in performance between most of the algorithms was not statistically significant.
CONCLUSIONS/SIGNIFICANCE
Our results support the choice of PLIER+16 for the preprocessing of clinical Affymetrix microarray data. However, other algorithms performed similarly and are probably also good choices
Regional effect on urban atmospheric nucleation
Secondary aerosol particle production via new particle formation (NPF) has been shown to be a major contributor to the global aerosol load. NPF has also been observed frequently in urban environments. Here, we investigate the effect of regional NPF on urban aerosol load under well-defined atmospheric conditions. The Carpathian Basin, the largest orogenic basin in Europe, represents an excellent opportunity for exploring these interactions. Based on long-term observations, we revealed that NPF seen in a central large city of the basin (Budapest) and its regional background occur in a consistent and spatially coherent way as a result of a joint atmospheric phenomenon taking place on large horizontal scales. We found that NPF events at the urban site are usually delayed by > 1 h relative to the rural site or even inhibited above a critical condensational sink level. The urban processes require higher formation rates and growth rates to be realized, by mean factors of 2 and 1.6, respectively, than the regional events. Regional-and urban-type NPF events sometimes occur jointly with multiple onsets, while they often exhibit dynamic and timing properties which are different for these two event types.Peer reviewe
Effect of Sprouting Temperature on Durum Wheat (Triticum Durum) Sprouts Nutritional Properties and Bioactive Compounds
Sprouting is an old food engineering tool to improve edible seeds nutritional value. It can improve carbohydrate digestibility and enhance levels of bioactive compounds. These changes are strongly related to sprouting conditions%253A temperature, light, duration. The aim of this research was to evaluate the effect of sprouting temperature on sprouts bioactive molecules and proximate composition of Chili Tunisian durum wheat (Triticum durum) seeds. Hence, two temperatures were tested%253A 18deg%253BC and 25deg%253BC. Analysis of ashes, proteins, lipids, reducing sugars, carotenoids, vitamin C, vitamin E, and total phenols contents and DPPH radical scavenging activity were done. Our results indicated that temperature influenced significantly proximate composition of sprouts, as well as bioactive compounds. Vitamin C and tocopherols levels were higher at 25deg%253BC, than in raw seeds. In contrast, a temperature of 18deg%253BC led to highest amounts of carotenoids and total phenols. In addition, antioxidant properties of durum wheat seeds were improved by sprouting only at 18deg%253BC. In conclusion, evolution of nutritional properties and bioactive compounds in sprouts were strongly dependent on sprouting temperature used
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Association between serum resistin level and outcomes in kidney transplant recipients.
Resistin is an adipocytokine that is associated with inflammation, coronary artery disease, and other types of cardiovascular disease among patients with normal kidney function. However, little is known about the association of resistin with outcomes in kidney transplant recipients. We collected socio-demographic and clinical parameters, medical and transplant history, and laboratory data from 988 prevalent kidney transplant recipients enrolled in the Malnutrition-Inflammation in Transplant-Hungary Study (MINIT-HU study). Serum resistin levels were measured at baseline. Associations between serum resistin level and death with a functioning graft over a 6-year follow-up period were examined in unadjusted and adjusted models. The mean±SD age of the study population was 51 ± 13 years, among whom 57% were men and 21% were diabetics. Median serum resistin concentrations were significantly higher in patients who died with a functioning graft as compared to those who did not die during the follow-up period (median [IQR]: 22[15-26] vs. 19[14-22] ng/ml, respectively; P < 0.001). Higher serum resistin level was associated with higher mortality risk in both unadjusted and fully adjusted models: HRs (95% CI): 1.33(1.16-1.54) and 1.21(1.01-1.46), respectively. In prevalent kidney transplant recipients, serum resistin was an independent predictor of death with a functioning graft
Dbx1-derived pyramidal neurons are generated locally in the developing murine neocortex
The neocortex generates at the dorsal region of the pallium in the forebrain. Several adjacent structures also contribute with neurons to neocortex. Ventral pallium is considered to generate several populations of neurons that arrive through tangential migration to the neocortex. Amongst them are the Cajal-Retzius cells and some transient pyramidal neurons. However, the specific site and timing of generation, trajectory of migration and actual contribution to the pyramidal population remains elusive. Here we investigate the spatio-temporal origin of neuronal populations from ventral pallium in an in vivo model, using a transposase mediated in utero electroporation method in embryonic mouse in vivo. From E11 to E14 cells born at the lateral corner of the neocortical neuroepithelium including the ventral pallium migrated ventro-laterally to settle all areas of the ventral telencephalon. Specifically, neurons migrated into amygdala, olfactory cortices and claustrum. However, we found no evidence for any neurons migrating tangentially towards the neocortex, regardless the antero-posterior level and developmental time of the electroporation. Our results challenge the described ventral-pallial origin of the transient pyramidal neuron population. In order to find the exact origin of cortical neurons that were previously Dbx1-fate mapped we used the promoter region of the murine Dbx1 locus to selectively target Dbx1-expressing progenitors and label their lineage. We found these progenitors in low numbers in all pallial areas, and not only in the ventral pallial ventricular zone. Our findings on the local cortical origin of the Dbx1-expressing pyramidal neurons reconcile the observation of Dbx1 expressing neurons in the cortex without evidence of dorsal tangential migration from ventral pallium and provide a new framework for the origin of the transient Dbx1-derived pyramidal neuron population. We conclude that these neurons are born locally within the dorsal pallial neuroepithelium
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