High-temperature limit of Breit-Wheeler pair production in a black-body field

This paper presents an analytic expression for the high-temperature limit of Breit-Wheeler pair production in a black-body field to lowest order in perturbation theory, of interest in early-universe cosmology. The limit is found to be a good approximation for temperatures above about three times the electron rest energy. It is also found that coupling to low-energy processes remains important at arbitrarily high temperatures, due to the exchange of a low-energy virtual fermion near the mass shell. This appears mathematically in the rate as a logarithmic factor of the photon temperature divided by the electron rest mass

Control of radiative processes using tunable plasmonic nanopatch antennas.

The radiative processes associated with fluorophores and other radiating systems can be profoundly modified by their interaction with nanoplasmonic structures. Extreme electromagnetic environments can be created in plasmonic nanostructures or nanocavities, such as within the nanoscale gap region between two plasmonic nanoparticles, where the illuminating optical fields and the density of radiating modes are dramatically enhanced relative to vacuum. Unraveling the various mechanisms present in such coupled systems, and their impact on spontaneous emission and other radiative phenomena, however, requires a suitably reliable and precise means of tuning the plasmon resonance of the nanostructure while simultaneously preserving the electromagnetic characteristics of the enhancement region. Here, we achieve this control using a plasmonic platform consisting of colloidally synthesized nanocubes electromagnetically coupled to a metallic film. Each nanocube resembles a nanoscale patch antenna (or nanopatch) whose plasmon resonance can be changed independent of its local field enhancement. By varying the size of the nanopatch, we tune the plasmonic resonance by ∼ 200 nm, encompassing the excitation, absorption, and emission spectra corresponding to Cy5 fluorophores embedded within the gap region between nanopatch and film. By sweeping the plasmon resonance but keeping the field enhancements roughly fixed, we demonstrate fluorescence enhancements exceeding a factor of 30,000 with detector-limited enhancements of the spontaneous emission rate by a factor of 74. The experiments are supported by finite-element simulations that reveal design rules for optimized fluorescence enhancement or large Purcell factors

Ultrasonics Guided Waves for Piping Inspection

An ultrasonic guided wave system for pipe inspection is proposed. Using guided wave experience to date on a variety of different tubing problems, feasibility experiments have already been conducted on piping under insulation in both a laboratory and chemical processing facility field environment. Several guided wave techniques are introduced, one using a broad banded variable angle beam transducer on a curved shoe, and one on a newly developed pipe comb system. Discussion on both axisymmetric and non-axisymmetric wave propagation is presented.</p

A Global Survey of Current Zoo Housing and Husbandry Practices for Fossa: A Preliminary Review

This is the final version. Available on open access from MDPI via the DOI in this recordData Availability Statement: The data that support the findings of this study are available from the corresponding author, J.J.H., upon reasonable request.The fossa is a specialized Malagasy carnivore housed in ex situ facilities since the late 19th century. Moderate breeding success has occurred since the 1970s, and welfare issues (notably stereotypic pacing behaviour) are commonly documented. To understand challenges relating to fossa housing and husbandry (H&H) across global facilities and to identify areas of good practice that dovetail with available husbandry standards, a survey was distributed to ZIMS-registered zoos in 2017. Results showed that outdoor housing area and volume varied greatly across facilities, the majority of fossa expressed unnatural behaviours, with pacing behaviour the most frequently observed. All fossa received enrichment, and most had public access restricted to one or two sides of the enclosure. The majority of fossa were locked in/out as part of their daily management and forty-one percent of the fossa surveyed as breeding individuals bred at the zoo. Dense cover within an enclosure, restricted public viewing areas, a variable feeding schedule and limited view of another species from the fossa exhibit appear to reduce the risk of unnatural behavior being performed. The achievement of best practice fossa husbandry may be a challenge due to its specialized ecology, the limited wild information guiding captive care, and the range of housing dimensions and exhibit features provided by zoos that makes identification of standardized practices difficult. We recommended that holders evaluate how and when enrichment is provided and assess what they are providing for environmental complexity as well as consider how the public views their fossa

An optimised tissue disaggregation and data processing pipeline for characterising fibroblast phenotypes using single-cell RNA sequencing

Single-cell RNA sequencing (scRNA-Seq) provides a valuable platform for characterising multicellular ecosystems. Fibroblasts are a heterogeneous cell type involved in many physiological and pathological processes, but remain poorly-characterised. Analysis of fibroblasts is challenging: these cells are difficult to isolate from tissues, and are therefore commonly under-represented in scRNA-seq datasets. Here, we describe an optimised approach for fibroblast isolation from human lung tissues. We demonstrate the potential for this procedure in characterising stromal cell phenotypes using scRNA-Seq, analyse the effect of tissue disaggregation on gene expression, and optimise data processing to improve clustering quality. We also assess the impact of in vitro culture conditions on stromal cell gene expression and proliferation, showing that altering these conditions can skew phenotypes

Focal osteoporosis defects play a key role in hip fracture

$\textbf{BACKGROUND}$: Hip fractures are mainly caused by accidental falls and trips, which magnify forces in well-defined areas of the proximal femur. Unfortunately, the same areas are at risk of rapid bone loss with ageing, since they are relatively stress-shielded during walking and sitting. Focal osteoporosis in those areas may contribute to fracture, and targeted 3D measurements might enhance hip fracture prediction. In the FEMCO case-control clinical study, Cortical Bone Mapping (CBM) was applied to clinical computed tomography (CT) scans to define 3D cortical and trabecular bone defects in patients with acute hip fracture compared to controls. Direct measurements of trabecular bone volume were then made in biopsies of target regions removed at operation. $\textbf{METHODS}$: The sample consisted of CT scans from 313 female and 40 male volunteers (158 with proximal femoral fracture, 145 age-matched controls and 50 fallers without hip fracture). Detailed Cortical Bone Maps (c.5580 measurement points on the unfractured hip) were created before registering each hip to an average femur shape to facilitate statistical parametric mapping (SPM). Areas where cortical and trabecular bone differed from controls were visualised in 3D for location, magnitude and statistical significance. Measures from the novel regions created by the SPM process were then tested for their ability to classify fracture versus control by comparison with traditional CT measures of areal Bone Mineral Density (aBMD). In women we used the surgical classification of fracture location ('femoral neck' or 'trochanteric') to discover whether focal osteoporosis was specific to fracture type. To explore whether the focal areas were osteoporotic by histological criteria, we used micro CT to measure trabecular bone parameters in targeted biopsies taken from the femoral heads of 14 cases. $\textbf{RESULTS}$: Hip fracture patients had distinct patterns of focal osteoporosis that determined fracture type, and CBM measures classified fracture type better than aBMD parameters. CBM measures however improved only minimally on aBMD for predicting any hip fracture and depended on the inclusion of trabecular bone measures alongside cortical regions. Focal osteoporosis was confirmed on biopsy as reduced sub-cortical trabecular bone volume. $\textbf{CONCLUSION}$: Using 3D imaging methods and targeted bone biopsy, we discovered focal osteoporosis affecting trabecular and cortical bone of the proximal femur, among men and women with hip fracture.Arthritis Research UK (grant no. ARC17822) and Cambridge National Institute for Health Research (NIHR) Biomedical Research Centre

One-carbon metabolism in cancer

Cells require one-carbon units for nucleotide synthesis, methylation and reductive metabolism, and these pathways support the high proliferative rate of cancer cells. As such, anti-folates, drugs that target one-carbon metabolism, have long been used in the treatment of cancer. Amino acids, such as serine are a major one-carbon source, and cancer cells are particularly susceptible to deprivation of one-carbon units by serine restriction or inhibition of de novo serine synthesis. Recent work has also begun to decipher the specific pathways and sub-cellular compartments that are important for one-carbon metabolism in cancer cells. In this review we summarise the historical understanding of one-carbon metabolism in cancer, describe the recent findings regarding the generation and usage of one-carbon units and explore possible future therapeutics that could exploit the dependency of cancer cells on one-carbon metabolism

The Inspection of Chemical Plant Pipework Using Lamb Waves: Defect Sensitivity and Field Experience

Corrosion and pitting defects in pipework are major problems in the oil, chemical and other industries. These defects can occur at the outer or inner surface of the pipe and can lead to a serious loss of pipe wall thickness. As a high proportion of industrial pipelines are insulated, this means that even external corrosion cannot readily be detected without the removal of the insulation, which in most cases is prohibitively expensive.</p

Corrigendum: Chronic Exposure to Malaria Is Associated with Inhibitory and Activation Markers on Atypical Memory B Cells and Marginal Zone-Like B Cells

[This corrects the article DOI: 10.3389/fimmu.2017.00966.]

Rotation and Spin in Physics

We delineate the role of rotation and spin in physics, discussing in order Newtonian classical physics, special relativity, quantum mechanics, quantum electrodynamics and general relativity. In the latter case, we discuss the generalization of the Kepler formula to post-Newtonian order $(c^{-2}$) including spin effects and two-body effects. Experiments which verify the theoretical results for general relativistic spin-orbit effects are discussed as well as efforts being made to verify the spin-spin effects