Is PPARβ/δ a Retinoid Receptor?

The broad ligand-binding characteristic of PPARβ/δ has long hampered identification of physiologically-meaningful ligands for the receptor. The observations that the activity of PPARβ/δ is supported by fatty acid binding protein 5 (FABP5), which directly delivers ligands from the cytosol to the receptor, suggest that bona fide PPARβ/δ ligands both activate the receptor, and trigger the nuclear translocation of FABP5. Using these criteria, it was recently demonstrated that all-trans-retinoic acid (RA), the activator of the classical retinoic acid receptor RAR, also serves as a ligand for PPARβ/δ. Partitioning of RA between its two receptors was found to be regulated by FABP5, which delivers it to PPARβ/δ, and cellular RA binding protein II (CRABP-II), which targets it to RAR. Consequently, RA activates PPARβ/δ in cells that display a high FABP5/CRABP-II expression ratio. It remains to be clarified whether compounds other than RA may also serve as endogenous activators for this highly promiscuous protein

Quantum fluxes at the inner horizon of a spinning black hole

Rotating or charged classical black holes in isolation possess a special surface in their interior, the Cauchy horizon, beyond which the evolution of spacetime (based on the equations of General Relativity) ceases to be deterministic. In this work, we study the effect of a quantum massless scalar field on the Cauchy horizon inside a rotating (Kerr) black hole that is evaporating via the emission of Hawking radiation (corresponding to the field being in the Unruh state). We calculate the flux components (in Eddington coordinates) of the renormalized stress-energy tensor of the field on the Cauchy horizon, as functions of the black hole spin and of the polar angle. We find that these flux components are generically non-vanishing. Furthermore, we find that the flux components change sign as these parameters vary. The signs of the fluxes are important, as they provide an indication of whether the Cauchy horizon expands or crushes (when backreaction is taken into account). Regardless of these signs, our results imply that the flux components generically diverge on the Cauchy horizon when expressed in coordinates which are regular there. This is the first time that irregularity of the Cauchy horizon under a semiclassical effect is conclusively shown for (four-dimensional) spinning black holes

Relationships between soil macroinvertebrates and nonnative feral pigs (Sus scrofa) in Hawaiian tropical montane wet forests

Abstract Nonnative feral pigs (Sus scrofa) are recognized throughout the New World as a highly significant introduced species in terms of ecosystem alteration. Similarly, nonnative soil macroinvertebrates (e.g. earthworms, ground beetles) invade and alter the structure and function of native habitats globally. However, the relationship between feral pigs and soil macroinvertebrates remains largely unknown. This study analyzed relationships between these taxa using nine sites located inside and outside of feral pig management units representing a * 25 year chronosequence of removal in tropical montane wet forests in Hawai‘i. Soil macroinvertebrates were sampled from plots categorized as: actively trampled by feral pigs, actively rooted by feral pigs, feral pigs present with no signs of recent activity, or feral pigs removed over time. In total, we found 13 families of primarily nonnative soil macroinvertebrates. Plots with active trampling correlated with lower total macroinvertebrate abundance, biomass, and family richness. Plots with active rooting were correlated with higher abundance of nonnative earthworms (Lumbricidae and Megascolicidae) and ground beetles (Carabidae). The abundance, biomass, and biodiversity of macroinvertebrates did not vary with time since feral pig removal. Collectively, these results indicate: (1) trampling by feral pigs negatively influences soil macroinvertebrates; (2) feral pigs either modify habitats while rooting thereby facilitating earthworm and ground beetle habitat use or selectively seek out target prey species of soil macroinvertebrates; and (3) removal of feral pigs has minimal impacts on soil macroinvertebrates over time. These results are important globally due to the broadly overlapping ranges of S. scrofa and nonnative macroinvertebrates

Methods of Fabricating Scintillators with Radioisotopes for Beta Battery Applications

Technology has been developed for a class of self-contained, long-duration power sources called beta batteries, which harvest the energy contained in the radioactive emissions from beta decay isotopes. The new battery is a significant improvement over the conventional phosphor/solar cell concept for converting this energy in three ways. First, the thin phosphor is replaced with a thick scintillator that is transparent to its own emissions. By using a scintillator sufficiently thick to completely stop all the beta particles, efficiency is greatly improved. Second, since the energy of the beta particles is absorbed in the scintillator, the semiconductor photodetector is shielded from radiation damage that presently limits the performance and lifetime of traditional phosphor converters. Finally, instead of a thin film of beta-emitting material, the isotopes are incorporated into the entire volume of the thick scintillator crystal allowing more activity to be included in the converter without self-absorption. There is no chemical difference between radioactive and stable strontium beta emitters such as Sr-90, so the beta emitter can be uniformly distributed throughout a strontium based scintillator crystal. When beta emitter material is applied as a foil or thin film to the surface of a solar cell or even to the surface of a scintillator, much of the radiation escapes due to the geometry, and some is absorbed within the layer itself, leading to inefficient harvesting of the energy. In contrast, if the emitting atoms are incorporated within the scintillator, the geometry allows for the capture and efficient conversion of the energy of particles emitted in any direction. Any gamma rays associated with secondary decays or Bremsstrahlung photons may also be absorbed within the scintillator, and converted to lower energy photons, which will in turn be captured by the photocell or photodiode. Some energy will be lost in this two-stage conversion process (high-energy particle to low-energy photons to electric current). The geometric advantage partially offsets this as well, since the absorption depth of high-energy beta radiation is much larger than the depth of a p-n junction. Thus, in a p-n junction device, much of the radiation is absorbed far away from the junction, and the electron- hole pairs are not all effectively collected. In contrast, with a transparent scintillator the radiation can be converted to light in a larger volume, and all of the light can be collected in the active region of the photodiode. Finally, the new device is more practical because it can be used at much higher power levels without unduly shortening its lifetime. While the crystal structure of scintillators is also subject to radiation damage, their performance is far more tolerant of defects than that of semiconductor junctions. This allows the scintillator- based approach to use both higher energy isotopes and larger quantities of the isotopes. It is projected that this technology has the potential to produce a radioisotope battery with up to twice the efficiency of presently used systems

Correlation between the anti-Müllerian hormone and endovaginal ultrasound in the predictivity of polycystic ovary syndrome at Chracerh

Background: Polycystic ovary syndrome (PCOS) is a heterogeneous syndrome posing diagnostic problems in current practice, because of the cumbersomeness associated with the application of the criteria that define it; giving rise to over or under diagnosis of it. Anti-Müllerian hormone (AMH) is an effective alternative in this case, being a stable, reproducible and non-operator dependent marker to diagnose PCOS due to the link that binds it to the multiple pre-antral follicles in the ovaries of PCOS patients. The aim of this study was to determine the threshold value of AMH required to define PCOS in our African population, by revealing the correlation with antral follicles count (AFC) on endovaginal ultrasound.Methods: We carried out a comparative cross-sectional study, with retrospective data collection in 23 infertile patients diagnosed with PCOS according to the Rotterdam 2003 criteria, and 23 non-PCOS infertile controls having performed the AMH test using the Immunotech technique at CHRACERH. Endovaginal ultrasound (U/S) was performed using a 7.5 mega Hertz (MHz) transvaginal transducer by different qualified operators (radiologists, gynecologists). The comparison of the two independent groups (PCOS and non-PCOS) was performed by the Student t-test; correlations between AMH, age, AFC and ovarian volume obtained by the Pearson test; and the diagnostic power of AMH test in PCOS was evaluated by receiver operating characteristic curves (ROC).Results: AMH was approximately twice as high in PCOS compared to controls (6.09 versus 3.80, P <0.001) and was inversely correlated with age (r = -0.301; P ˂0.05); significantly correlated antral follicle count (R = 0.85, P <0.0001) and ovarian volume (r = 0.625, P <0.0001). ROC analysis revealed that the AMH test was very informative for the diagnosis of PCOS with an area under the curve (AUC) at 0.90 (0.81-0.99; 95% CI); and the threshold value given by the farthest point of the diagonal representing the nil contribution test was 4.40 ng/L, and predicted PCOS with a sensitivity of 96% and a specificity of 70%.Conclusions: AMH is a predictive marker for PCOS. It is highly correlated with AFC and ovarian volume and appears to decrease with age. It offers good diagnostic performance in PCOS, with a threshold value of 4.40 ng/L for a sensitivity of 96% and specificity of 70%

Locus coeruleus norepinephrine activity mediates sensory-evoked awakenings from sleep

A defining feature of sleep is reduced responsiveness to external stimuli, but the mechanisms mediating sensory-evoked arousal remain unclear. We hypothesized that reduced locus coeruleus (LC) norepinephrine (NE) activity during sleep mediates unresponsiveness, and its action promotes sensory-evoked awakenings. We tested this using electrophysiological, behavioral, pharmacological, and optogenetic techniques alongside auditory stimulation in freely behaving rats. We found that systemic reduction in NE signaling lowered probability of sound-evoked awakenings (SEAs). The level of tonic LC activity during sleep anticipated SEAs. Optogenetic LC activation promoted arousal as evident in sleep-wake transitions, EEG desynchronization, and pupil dilation. Minimal LC excitation before sound presentation increased SEA probability. Optogenetic LC silencing using a soma-targeted anion-conducting channelrhodopsin (stGtACR2) suppressed LC spiking and constricted pupils. Brief periods of LC opto-silencing reduced the probability of SEAs. Thus, LC-NE activity determines the likelihood of sensory-evoked awakenings, and its reduction during sleep constitutes a key factor mediating behavioral unresponsiveness.This work was supported by the Israel Science Foundation (ISF) grants 1326/15 and 51/11 (I-CORE cognitive sciences) and the Adelis Foundation (to Y.N.). E.J.K. is an INSERM fellow. O.Y. is supported by the European Research Council (ERC-2013-StG OptoNeuromod 337637) and the Adelis Foundation. CAV2 vector production was supported by CNRS BioCampus (Montpellier). A.S. is a Wellcome Trust-funded PhD student on the Neural Dynamics program. A.J.K. is supported by the ISF grant 762/16 and the European Society of Anaesthesiology young investigator startup gran

Predicting the impacts of chemical pollutants on animal groups

Wildlife are exposed to an increasing number and diversity of chemical pollutants.Chemical pollutants can elicit a range of sublethal effects on individual organisms, but research on how these contaminants affect social interactions and animal groups is severely lacking.It is imperative that perspectives from behavioural ecology and ecotoxicology are integrated, to increase our understanding of how contaminant effects on individuals might cascade to group-level processes.We present a conceptual framework for researchers and practitioners to guide the study of how chemical pollutants might affect the emergence, organisation, and function of animal social groups.Chemical pollution is among the fastest-growing agents of global change. Synthetic chemicals with diverse modes-of-action are being detected in the tissues of wildlife and pervade entire food webs. Although such pollutants can elicit a range of sublethal effects on individual organisms, research on how chemical pollutants affect animal groups is severely lacking. Here we synthesise research from two related, but largely segregated fields – ecotoxicology and behavioural ecology – to examine pathways by which chemical contaminants could disrupt processes that govern the emergence, self-organisation, and collective function of animal groups. Our review provides a roadmap for prioritising the study of chemical pollutants within the context of sociality and highlights important methodological advancements for future research

Characterization of a hollow core fibre-coupled near field terahertz probe

We describe the design and performance of a freely positionable THz near field probe based on a hollow core photonic crystal fibre-coupled photoconducting dipole antenna with an integrated sub-wavelength aperture. Experimental studies of the spatial resolution are compared with detailed finite element electromagnetic simulations and imaging artefacts that are a particular feature of this type of device are discussed. We illustrate the potential applications with descriptions of time domain near field studies of surface waves on a metamaterial and multimode propagation in a parallel plate waveguide