Wavelet-based functional mixed models for the analysis of lateralized readiness potentials

Event-related potentials recorded from the human scalp using EEG can provide important information about how the human brain processes information. To unravel cognitive processes, the so-called lateralized readiness potential (LRP) has become an especially useful temporal marker within the area of chrono-psychophysiology. Simple parametric modeling of such LRP-curves is unsufficient and nonparametric approaches allowing for arbitrary functional forms are warranted. Smoothing methods using global bandwidths and penalties are often used to model such longitudinal data with curves but fail to capture spatial heterogeneity and local features like peaks. Using kernels with local bandwidths and adaptive penalties can address these issues in the single-function setting, but are not easily generalized to the multiple-function setting. Wavelet-based functional mixed models (WFMM) as proposed by Morris and Carroll (JRSS B, 2006, Vol.68, pp179-199) may offer a valuable alternative in this setting. We aim to illustrate WFMM to LRP-data from a task switching study. More specifically we are interested to determine the timepoint/latency at which a consistent divergence in LRP-signals between task repetitions and task switches can be observed and to investigate whether this latency is influenced by other factors (such as cuing type, indication requirement, ...). Repeated testing at different timepoints induces a multiple testing problem (MTP). We compare the performance of different multiple testing procedures using the pointwise posterior credible intervals versus inference from the joint posterior credible interval

Acetate as a model for aspartate-based CXCR4 chemokine receptor binding of cobalt and nickel complexes of cross-bridged tetraazamacrocycles

A number of disease states including WHIM syndrome, HIV infection and cancer have been linked to the chemokine receptor CXCR4. High-affinity CXCR4 antagonist transition metal complexes of configurationally restricted bis-tetraazamacrocyclic ligands have been identified in previous studies. Recently synthesised and structurally characterised Co2+/Co3+ and Ni2+ acetate complexes of mono-macrocycle cross-bridged ligands have been used to mimic their known coordination interaction with the aspartate side chains on binding to CXCR4. Here, X-ray crystal structures for three Co2+/Co3+ acetate complexes and five Ni2+ acetate complexes are presented and demonstrate flexibility in the mode of binding to the acetate ligand concomitantly with the requisite cis-V-configured cross-bridged tetraazamacrocyle. Complexes of the smaller Co3+ metal ion exclusively bind acetate by chelating both oxygens of acetate. Larger Co2+ and Ni2+ metal ions in cross-bridged tetraazamacrocycles show a clear tendency to coordinate acetate in a monodentate fashion with a coordinated water molecule completing the octahedral coordination sphere. However, in unbridged tetraazamacrocycle acetate structures reported in the literature, the coordination preference is to chelate both acetate oxygens. We conclude that the short ethylene cross-bridge restricts the equatorial bulk of the macrocycle, prompting the metal ion to fill the equator with the larger monodentate acetate plus water ligand set. In unbridged ligand examples, the flexible macrocycle expands equatorially and generally only allows chelation of the sterically smaller acetate alone. These results provide insight for generation of optimised bis-macrocyclic CXCR4 antagonists utilising cobalt and nickel ions

Biomarkers for Severity of Spinal Cord Injury in the Cerebrospinal Fluid of Rats

One of the major challenges in management of spinal cord injury (SCI) is that the assessment of injury severity is often imprecise. Identification of reliable, easily quantifiable biomarkers that delineate the severity of the initial injury and that have prognostic value for the degree of functional recovery would significantly aid the clinician in the choice of potential treatments. To find such biomarkers we performed quantitative liquid chromatography-mass spectrometry (LC-MS/MS) analyses of cerebrospinal fluid (CSF) collected from rats 24 h after either a moderate or severe SCI. We identified a panel of 42 putative biomarkers of SCI, 10 of which represent potential biomarkers of SCI severity. Three of the candidate biomarkers, Ywhaz, Itih4, and Gpx3 were also validated by Western blot in a biological replicate of the injury. The putative biomarkers identified in this study may potentially be a valuable tool in the assessment of the extent of spinal cord damage

Testing a global standard for quantifying species recovery and assessing conservation impact.

Recognizing the imperative to evaluate species recovery and conservation impact, in 2012 the International Union for Conservation of Nature (IUCN) called for development of a "Green List of Species" (now the IUCN Green Status of Species). A draft Green Status framework for assessing species' progress toward recovery, published in 2018, proposed 2 separate but interlinked components: a standardized method (i.e., measurement against benchmarks of species' viability, functionality, and preimpact distribution) to determine current species recovery status (herein species recovery score) and application of that method to estimate past and potential future impacts of conservation based on 4 metrics (conservation legacy, conservation dependence, conservation gain, and recovery potential). We tested the framework with 181 species representing diverse taxa, life histories, biomes, and IUCN Red List categories (extinction risk). Based on the observed distribution of species' recovery scores, we propose the following species recovery categories: fully recovered, slightly depleted, moderately depleted, largely depleted, critically depleted, extinct in the wild, and indeterminate. Fifty-nine percent of tested species were considered largely or critically depleted. Although there was a negative relationship between extinction risk and species recovery score, variation was considerable. Some species in lower risk categories were assessed as farther from recovery than those at higher risk. This emphasizes that species recovery is conceptually different from extinction risk and reinforces the utility of the IUCN Green Status of Species to more fully understand species conservation status. Although extinction risk did not predict conservation legacy, conservation dependence, or conservation gain, it was positively correlated with recovery potential. Only 1.7% of tested species were categorized as zero across all 4 of these conservation impact metrics, indicating that conservation has, or will, play a role in improving or maintaining species status for the vast majority of these species. Based on our results, we devised an updated assessment framework that introduces the option of using a dynamic baseline to assess future impacts of conservation over the short term to avoid misleading results which were generated in a small number of cases, and redefines short term as 10 years to better align with conservation planning. These changes are reflected in the IUCN Green Status of Species Standard

Cell-based assays to characterize ligands for chemokine receptor CXCR4

status: publishe

Study of candidate ligands for two leucine-rich repeats containing G protein-coupled receptors in the fruit fly, Drosophila melanogaster.

Leucine-rich repeats bevattende G-proteïne gekoppelde receptoren (L GRs) worden gekenmerkt door een groot N-terminaal, extracellulair domein , van belang voor specifieke binding van het hormoon. In vertebrat en spelen LGRs, als receptoren voor glycoproteïne hormonen en relaxine v erwante peptiden, een essentiële rol in de reproductiefysiologie en het metabolisme. Twee weesreceptoren van het fruitvliegje, Drosophila melanogaster, dLGR1 en dLGR2, zijn structureel verwant met vertebrate n LGRs. Wanneer zij recombinant tot expressie gebracht worden in z oogdiercellen, vertonen beide fruitvlieg LGRs een basale activiteit die aanleiding geeft tot een verhoogde intracellulaire cAMP concentratie. In deze studie werden, na in silico analyse van het fruitvlieg genoom , twee cystine knot proteïnen, die sequentiegelijkenis vertonen met gl ycoproteïne hormoon subeenheden, gekloneerd en geproduceerd in eukaryote celexpressie-systemen. Zij veroorzaakten evenwel geen reproduceer bare cAMP respons in dLGR1 exprimerende COS-7 cellen. Vertrekkende van enkele partiële peptide fragmenten, afgeleid van bursic on activiteit vertonende extracten van kakkerlakken, werden twee additio nele fruitvlieg cystine knot proteïnen gekarakteriseerd. Wanneer deze samen tot expressie worden gebracht, vormen ze een biologisch acti ef heterodimeer dat sterke uitkleuring en verharding van de cuticula van insecten induceert. Ditzelde heterodimeer molecule, bursicon, sti muleert specifiek de fruitvlieg dLGR2, op een concentratie-afhankelijke manier. Homologen van al deze vlieg cystine knot proteïnen werden geïdentifice erd in verschillende klassen van ongewervelden. Dit maakt het moge lijk om in de toekomst een meer gedetailleerde, vergelijkende functionel e analyse van deze evolutief geconserveerde proteïnen, uit te voeren in een uitgebreide groep van dieren. In deze studie wordt voor het ee rst de fysiologische ligand voor een LGR van invertebraten beschreven.&n bsp; Meer dan veertig jaar na de initiële ontdekking van zijn bioactivit eit, werd het neurohormoon bursicon, van cruciaal belang voor insecten, en bijgevolg de meeste dieren op aarde, moleculair gekarakteriseerd.status: publishe

Recycling of rare earths from lamp phosphor waste: enhanced dissolution of LaPO4:Ce3+,Tb3+ by mechanical activation

Oral presentation by Steff Van Loystatus: publishe

Recycling of rare earths from lamp phosphor waste: Enhanced dissolution of LaPO4:Ce3+,Tb3+ by mechanical activation

With the promoted use of compact fluorescent lamps and the increasing amount of stockpiled compact fluorescent lamp waste, lamp phosphors are becoming an interesting secondary source for critical metals (yttrium, europium and terbium). This paper explores on the mechanism of a new potential hydrometallurgical route to improve the recovery efficiency of rare-earth elements from the green phosphor LaPO4:Ce3+,Tb3+ using mechanical activation as a pretreatment step prior to leaching. By applying an intense frictional action, the leaching yields of rare-earth elements were enhanced from 0.9% to 81% at room temperature, as a consequence of the change in activation energy. The shrinking core model was employed for modelling the leaching kinetics of the rare-earth elements and to calculate the decreasing apparent activation energy of the unmilled and milled samples (from 68 kJ mol−1 to 1.4 kJ mol−1). This difference can be explained by the physicochemical changes, including structural decomposition, specific surface area increase and particle size reduction, which were related to the corresponding leaching pattern. The optimized mechanical activation procedure was successfully applied to lamp phosphor waste, containing a mix of different phosphors. After sequential removal of the halophosphate phosphor and the red YOX phosphor, 99.0%, 87.3% and 86.3% of La, Ce and Tb present in the LaPO4:Ce3+,Tb3+ phosphor could be dissolved. These observations provide more insight in the mechanical activation process and may contribute to a more sustainable alternative route to the rare-earth element recycling industry.status: publishe

Mechanochemical-Assisted Leaching of Lamp Phosphors: A Green Engineering Approach for Rare-Earth Recovery

Rare-earth elements (REEs) are essential metals for the design and development of sustainable energy applications. Recycling these elements from waste streams enriched in them is crucial for securing an independent future supply for sustainable applications. This study compares the mechanisms of mechanical activation prior to a hydrometallurgical acid-leaching process and a solvometallurgical mechanochemical leaching process for the recovery of REEs from green lamp phosphor, LaPO4:Ce3+,Tb3+. After 60 min of processing time, the REE leaching rates showed a significant enhancement of 60% after cycled mechanical activation, and 98% after the combined mechanochemical leaching process. High-resolution transmission electron microscopy (HR-TEM) imaging disclosed the cause for the improved REE leaching rates: The improved leaching and leaching patterns could be attributed to changes in the crystal morphology from monocrystalline to polycrystalline. Reduction of the crystallite size to the nanoscale in a polycrystalline material creates irregular packing of chemical units, resulting in an increase in defect-rich grain boundaries in the crystals, which enhances the leaching process. A solvometallurgical method was developed to combine the mechanical activation and leaching process into a single step, which is beneficial for operational cost. This results in an efficient and simple process that provides an alternative and greener recycling route for lamp phosphor waste. Keywords: Mechanochemistry, Rare-earth elements, Lamp phosphor waste, Ball-milling, Solvometallurg

Mechanochemical-Assisted Leaching of Lamp Phosphors: A Green Engineering Approach for Rare-Earth Recovery

© 2018 THE AUTHORS Rare-earth elements (REEs) are essential metals for the design and development of sustainable energy applications. Recycling these elements from waste streams enriched in them is crucial for securing an independent future supply for sustainable applications. This study compares the mechanisms of mechanical activation prior to a hydrometallurgical acid-leaching process and a solvometallurgical mechanochemical leaching process for the recovery of REEs from green lamp phosphor, LaPO4:Ce3+,Tb3+. After 60 min of processing time, the REE leaching rates showed a significant enhancement of 60% after cycled mechanical activation, and 98% after the combined mechanochemical leaching process. High-resolution transmission electron microscopy (HR-TEM) imaging disclosed the cause for the improved REE leaching rates: The improved leaching and leaching patterns could be attributed to changes in the crystal morphology from monocrystalline to polycrystalline. Reduction of the crystallite size to the nanoscale in a polycrystalline material creates irregular packing of chemical units, resulting in an increase in defect-rich grain boundaries in the crystals, which enhances the leaching process. A solvometallurgical method was developed to combine the mechanical activation and leaching process into a single step, which is beneficial for operational cost. This results in an efficient and simple process that provides an alternative and greener recycling route for lamp phosphor waste.status: publishe