Distinct subsets of unmyelinated primary sensory fibers mediate behavioral responses to noxious thermal and mechanical stimuli

Behavioral responses to painful stimuli require peripheral sensory neurons called nociceptors. Electrophysiological studies show that most C-fiber nociceptors are polymodal (i.e., respond to multiple noxious stimulus modalities, such as mechanical and thermal); nevertheless, these stimuli are perceived as distinct. Therefore, it is believed that discrimination among these modalities only occurs at spinal or supraspinal levels of processing. Here, we provide evidence to the contrary. Genetic ablation in adulthood of unmyelinated sensory neurons expressing the G protein-coupled receptor Mrgprd reduces behavioral sensitivity to noxious mechanical stimuli but not to heat or cold stimuli. Conversely, pharmacological ablation of the central branches of TRPV1+ nociceptors, which constitute a nonoverlapping population, selectively abolishes noxious heat pain sensitivity. Combined elimination of both populations yielded an additive phenotype with no additional behavioral deficits, ruling out a redundant contribution of these populations to heat and mechanical pain sensitivity. This double-dissociation suggests that the brain can distinguish different noxious stimulus modalities from the earliest stages of sensory processing

On the Feasibility of Quantifying Fibrous Cap Thickness With Acoustic Radiation Force Impulse (ARFI) Ultrasound

Acute cerebrovascular accidents are associated with the rupture of vulnerable atherosclerotic plaques in the carotid arteries. Fibrous cap thickness has been shown to be an important predictor of plaque rupture, but has been challenging to measure accurately with clinical noninvasive imaging modalities. The goals of this investigation were first, to evaluate the feasibility of using transcutaneous acoustic radiation force impulse (ARFI) ultrasound to quantify fibrous cap thickness and second, to optimize both imaging and motion tracking parameters to support such measurements. Fibrous caps with varying thickness (0.1 – 1.0 mm) were simulated using a simple layered geometry, and their mechanical response to an impulse of radiation force was solved using finite element method (FEM) modeling. Ultrasound tracking of FEM displacements was performed in Field II utilizing three center frequencies (6, 9, and 12 MHz) and eight motion tracking kernel lengths (0.5λ – 4λ). Additionally, fibrous cap thickness in two carotid plaques imaged in vivo was measured with ARFI and compared to matched histology. The results of this study demonstrate that 1) tracking pulse frequencies around 12 MHz are necessary to resolve caps around 0.2 mm, 2) large motion-tracking kernel sizes introduce bias into thickness measurements and overestimate the true cap thickness, and 3) color saturation settings on ARFI peak displacement images can impact thickness measurement accuracy substantially

Multiple elements in human β-globin locus control region 5′ HS 2 are involved in enhancer activity and position independent, transgene expression

The human β-globin Locus Control Region (LCR) has two important activities. First, the LCR opens a 200 kb chromosomal domain containing the human ε-, γ- and β-giobin genes and, secondly, these sequences function as a powerful enhancer of ε-, γ- and β-globin gene expression. Erythrold-specific, DNase I hypersensitive sites (HS) mark sequences that are critical for LCR activity. Previous experiments demonstrated that a 1.9 kb fragment containing the 5′ HS 2 site confers position-independent expression in transgenic mice and enhances human β-giobin gene expression 100-fold. Further analysis of this region demonstrates that multiple sequences are required for maximal enhancer activity; deletion of SP1, NF-E2, GATA-1 or USF binding sites significantly decrease β-globin gene expression. In contrast, no single site is required for position- independent transgene expression; all mice with site- specific mutations in 5′ HS 2 express human β-globin mRNA regardless of the site of transgene integration. Apparently, multiple combinations of protein binding sites in 5′ HS 2 are sufficient to prevent chromosomal position effects that inhibit transgene expression. © 1994 Oxford University Press

My heart is racing! Psychophysiological dynamics of skilled racecar drivers

Our purpose was to test the multi-action plan (MAP) model assumptions in which athletes’ psychophysiological patterns differ among optimal and suboptimal performance experiences. Nine professional drivers competing in premier race categories (e.g., Formula 3, Porsche GT3 Cup Challenge) completed the study. Data collection involved monitoring the drivers’ perceived hedonic tone, accuracy on core components of action, posture, skin temperature, respiration rate, and heart rate responses during a 40-lap simulated race. Time marks, gathered at three standardized sectors, served as the performance variable. The A1GP racing simulator (Allinsport, Modena) established a realistic race platform. Specifically, the Barcelona track was chosen due to its inherently difficult nature characterized by intermittent deceleration points. Idiosyncratic analyses showed large individual differences in the drivers’ psychophysiological profile, as well as distinct patterns in regards to optimal and suboptimal performance experiences. Limitations and future research avenues are discussed. Action (e.g., attentional control) and emotion (e.g., biofeedback training) centered applied sport psychology implications are advanced

Tuning localized plasmons in nanostructured substrates for surface-enhanced Raman scattering

Comprehensive reflectivity mapping of the angular dispersion of nanostructured arrays comprising of inverted pyramidal pits is demonstrated. By comparing equivalently structured dielectric and metallic arrays, diffraction and plasmonic features are readily distinguished. While the diffraction features match expected theory, localised plasmons are also observed with severely flattened energy dispersions. Using pit arrays with identical pitch, but graded pit dimensions, energy scaling of the localised plasmon is observed. These localised plasmons are found to match a simple model which confines surface plasmons onto the pit sidewalls thus allowing an intuitive picture of the plasmons to be developed. This model agrees well with a 2D finite-difference time-domain simulation which shows the same dependence on pit dimensions. We believe these tuneable plasmons are responsible for the surface-enhancement of the Raman scattering (SERS) of an attached layer of benzenethiol molecules. Such SERS substrates have a wide range of applications both in security, chemical identification, environmental monitoring and healthcare

Identifying Highly Connected Counties Compensates for Resource Limitations when Evaluating National Spread of an Invasive Pathogen

Surveying invasive species can be highly resource intensive, yet near-real-time evaluations of invasion progress are important resources for management planning. In the case of the soybean rust invasion of the United States, a linked monitoring, prediction, and communication network saved U.S. soybean growers approximately $200 M/yr. Modeling of future movement of the pathogen (Phakopsora pachyrhizi) was based on data about current disease locations from an extensive network of sentinel plots. We developed a dynamic network model for U.S. soybean rust epidemics, with counties as nodes and link weights a function of host hectarage and wind speed and direction. We used the network model to compare four strategies for selecting an optimal subset of sentinel plots, listed here in order of increasing performance: random selection, zonal selection (based on more heavily weighting regions nearer the south, where the pathogen overwinters), frequency-based selection (based on how frequently the county had been infected in the past), and frequency-based selection weighted by the node strength of the sentinel plot in the network model. When dynamic network properties such as node strength are characterized for invasive species, this information can be used to reduce the resources necessary to survey and predict invasion progress

Dark production of extracellular superoxide by the coral Porites astreoides and representative symbionts

© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Marine Science 3 (2016): 232, doi:10.3389/fmars.2016.00232.The reactive oxygen species (ROS) superoxide has been implicated in both beneficial and detrimental processes in coral biology, ranging from pathogenic disease resistance to coral bleaching. Despite the critical role of ROS in coral health, there is a distinct lack of ROS measurements and thus an incomplete understanding of underpinning ROS sources and production mechanisms within coral systems. Here, we quantified in situ extracellular superoxide concentrations at the surfaces of aquaria-hosted Porites astreoides during a diel cycle. High concentrations of superoxide (~10's of nM) were present at coral surfaces, and these levels did not change significantly as a function of time of day. These results indicate that the coral holobiont produces extracellular superoxide in the dark, independent of photosynthesis. As a short-lived anion at physiological pH, superoxide has a limited ability to cross intact biological membranes. Further, removing surface mucus layers from the P. astreoides colonies did not impact external superoxide concentrations. We therefore attribute external superoxide derived from the coral holobiont under these conditions to the activity of the coral host epithelium, rather than mucus-derived epibionts or internal sources such as endosymbionts (e.g., Symbiodinium). However, endosymbionts likely contribute to internal ROS levels via extracellular superoxide production. Indeed, common coral symbionts, including multiple strains of Symbiodinium (clades A to D) and the bacterium Endozoicomonas montiporae LMG 24815, produced extracellular superoxide in the dark and at low light levels. Further, representative P. astreoides symbionts, Symbiodinium CCMP2456 (clade A) and E. montiporae, produced similar concentrations of superoxide alone and in combination with each other, in the dark and low light, and regardless of time of day. Overall, these results indicate that healthy, non-stressed P. astreoides and representative symbionts produce superoxide externally, which is decoupled from photosynthetic activity and circadian control. Corals may therefore produce extracellular superoxide constitutively, highlighting an unclear yet potentially beneficial role for superoxide in coral physiology and health.This work was supported by a Postdoctoral Fellowship from the Ford Foundation (JD), the National Science Foundation under grants OCE 1225801 (JD) and OCE 1233612 (AA), the Ocean and Climate Change Institute of the Woods Hole Oceanographic Institution (CH), a BIOS Grant in aid award (SM), the Sidney Stern Memorial Trust (CH and AA), as well as an anonymous donor

Evidence for a correlation between the sizes of quiescent galaxies and local environment to z ~ 2

We present evidence for a strong relationship between galaxy size and environment for the quiescent population in the redshift range 1 < z < 2. Environments were measured using projected galaxy overdensities on a scale of 400 kpc, as determined from ~ 96,000 K-band selected galaxies from the UKIDSS Ultra Deep Survey (UDS). Sizes were determined from ground-based K-band imaging, calibrated using space-based CANDELS HST observations in the centre of the UDS field, with photometric redshifts and stellar masses derived from 11-band photometric fitting. From the resulting size-mass relation, we confirm that quiescent galaxies at a given stellar mass were typically ~ 50 % smaller at z ~ 1.4 compared to the present day. At a given epoch, however, we find that passive galaxies in denser environments are on average significantly larger at a given stellar mass. The most massive quiescent galaxies (M_stellar > 2 x 10^11 M_sun) at z > 1 are typically 50 % larger in the highest density environments compared to those in the lowest density environments. Using Monte Carlo simulations, we reject the null hypothesis that the size-mass relation is independent of environment at a significance > 4.8 sigma for the redshift range 1 < z < 2. In contrast, the evidence for a relationship between size and environment is much weaker for star-forming galaxies.Comment: Accepted for publication in MNRAS. 16 pages, 11 figures, 6 table

Bursts of activity in collective cell migration

Dense monolayers of living cells display intriguing relaxation dynamics, reminiscent of soft and glassy materials close to the jamming transition, and migrate collectively when space is available, as in wound healing or in cancer invasion. Here we show that collective cell migration occurs in bursts that are similar to those recorded in the propagation of cracks, fluid fronts in porous media and ferromagnetic domain walls. In analogy with these systems, the distribution of activity bursts displays scaling laws that are universal in different cell types and for cells moving on different substrates. The main features of the invasion dynamics are quantitatively captured by a model of interacting active particles moving in a disordered landscape. Our results illustrate that collective motion of living cells is analogous to the corresponding dynamics in driven, but inanimate, systems