Comparison of ultracold neutron sources for fundamental physics measurements

Ultracold neutrons (UCNs) are key for precision studies of fundamental parameters of the neutron and in searches for new CP violating processes or exotic interactions beyond the Standard Model of particle physics. The most prominent example is the search for a permanent electric dipole moment of the neutron (nEDM). We have performed an experimental comparison of the leading UCN sources currently operating. We have used a 'standard' UCN storage bottle with a volume of 32 liters, comparable in size to nEDM experiments, which allows us to compare the UCN density available at a given beam port.Comment: 20 pages, 30 Figure

Refinement of iron ore sinter phases : a silico-ferrite of calcium and aluminium (SFCA) and an Al-free SFC, and the effect on phase quantification by X-ray diffraction

Crystals of a silico-ferrite of calcium and aluminium (SFCA) and an Al-free SFC were prepared from the melt by slow cooling of synthetically prepared mixtures and examined by single-crystal diffraction methods. Both crystals belong to the space group P-1. SFC has lattice parameters a = 9.1255(3) Å, b = 10.1189(3) Å, c = 10.6183(2) Å, α = 63.9554(9)°, β = 84.4964(11)°, γ = 65.6706(9)° with a final R(|F|) = 0.024. SFCA has a cell with a = 9.0738(9)Å, b = 10.0474(10)Å, c = 10.5611(10) Å, α = 64.061(3)°, β = 84.356(3)°, γ = 65.722(3)° with a final R(|F|) = 0.030. The SFC structure was transformed to the cell used by Hamilton et al. (1989) and refined to an R(|F|) = 0.024. All the atomic positions are equivalent to those reported by Hamilton et al. (1989) with the exception of one (Ca,Fe) position and two oxygen positions that are displaced from the published positions by 0.5y (Ca,Fe1), 0.5z (O4), or 0.5x (O12). This is ascribed to transcription errors in the published crystal structure data. The calculated powder pattern of SFCA (this study) was compared with the experimental data and it shows that the low angle peak intensities agree significantly better than those calculated from the published atomic positions. Additional electron density is located in proximity to the octahedral and tetrahedral cation sites of the main structure. These positions, coupled with the partially occupied cation sites of the main structure, suggest a minor sharing of cations between the main cation sites and the additional sites.http://link.springer.com/journal/710hb2017ChemistryMaterials Science and Metallurgical Engineerin

Cancrinite-group minerals behavior at non-ambient conditions

Cancrinite-group minerals occur in the late stages of alkaline (SiO2)-undersaturated magmatism and in related effusive or contact rocks. So far only few studies have been devoted to the description of the thermo-elastic behavior,phase-stability and P /T -structure evolution (at the atomic scale) of this mineral group. Cancrinite-group minerals have an open-framework structure characterized by the [CAN]-topology. The [CAN]-framework shows large 12-ring channels, parallel to the c crystallographic axis, bound by columns of cages, the so-called can units. While very limited chemical variation is observed in the framework composition (the composition is almost always [Si6Al6O24]) a remarkable chemical variability is reported for the extraframework components in the cancrinite-group minerals. Two subgroups can be identified according to the extraframework content of the can units: the cancrinite- and the davyne-subgroups, showing Na-H2O and Ca-Cl chains, respectively. The channels are stuffed by cations, anions and molecules. We aimed to model the thermo-elastic behavior and the mechanisms of the (P ,T )-induced structure evolution of cancrinite-group minerals, with special interest on the role played by the extraframework population. The study was restricted to the following (CO3)-rich and (SO4)-rich end-members: cancrinite sensu stricto {[(Na,Ca)6(CO3)1.2 121.7][Na2(H2O)2][Al6Si6O24]}, vishnevite {[(Na,Ca,K)6(SO4)][Na2(H2O)2][Al6Si6O24]}, balliranoite {[(Na,Ca)6(CO3)1.2 121.7][Ca2Cl2][Al6Si6O24]} and davyne {[(Na,Ca,K)6((SO4),Cl)][Ca2Cl2][Al6Si6O24]}. Their high-P and low-T (T < 293 K) behavior was investigated by means of in-situ single-crystal X-ray diffraction, using diamond-anvil cells and (N2)-cryosystems, respectively. The high-T behavior of cancrinite has also been studied by means of in-situ single-crystal X-ray diffraction with a resistive heater. Cancrinite minerals share a similar volume compressibility and thermal expansivity at ambient conditions (cancrinite has KV0 = 45(2) GPa and \u3b1V,293K = 4.88(8)\ub710 125 K 121; vishnevite has KV0 = 49(2) GPa; balliranoite has KV0 = 48(3) GPa and \u3b1V,293K = 4.6(4)\ub710 125 K 121; davyne has KV0 = 46.5(11) GPa and \u3b1V,293K = 4.2(4)\ub710 125 K 121). However, these minerals show different thermo-elastic anisotropy schemes, more pronounced in the cancrinite-subgroup minerals. This behavior is governed by different deformation mechanisms of the crystal structure, which likely reflect the different coordination environments of the cage-cations between the minerals of the cancrinite-and davyne-subgroups (i.e. Na+ and Ca2+, respectively). In addition, a P -induced re-organization of the extraframework population is observed, in vishnevite, at P 65 3.5 GPa, suggesting that the channel-constituents can also affect the elastic and structural behavior and the phase stability of these minerals at non-ambient conditions. Besides common features likely ascribable to the [CAN]-topology, the nature of the extraframework population appears to control significantly the (P ,T )-induced structure evolution and thermo-elastic behavior of the cancrinite-group compounds. PL, GDG and MM acknowledge the Italian Ministry of Education, MIUR-Project: \u201cFuturo in Ricerca 2012 - ImPACT- RBFR12CLQD\u201d. MA acknowledges the ERC starting grant N. 307322 to FN

Community-specific evaluation of tool affordances in wild chimpanzees

The notion of animal culture, defined as socially transmitted community-specific behaviour patterns, remains controversial, notably because the definition relies on surface behaviours without addressing underlying cognitive processes. In contrast, human cultures are the product of socially acquired ideas that shape how individuals interact with their environment. We conducted field experiments with two culturally distinct chimpanzee communities in Uganda, which revealed significant differences in how individuals considered the affording parts of an experimentally provided tool to extract honey from a standardised cavity. Firstly, individuals of the two communities found different functional parts of the tool salient, suggesting that they experienced a cultural bias in their cognition. Secondly, when the alternative function was made more salient, chimpanzees were unable to learn it, suggesting that prior cultural background can interfere with new learning. Culture appears to shape how chimpanzees see the world, suggesting that a cognitive component underlies the observed behavioural patterns

Large-scale functional inference for skin-expressing lncRNAs using expression and sequence information

Long noncoding RNAs (lncRNAs) regulate the expression of protein-coding genes and have been shown to play important roles in inflammatory skin diseases. However, we still have limited understanding of the functional impact of lncRNAs in skin, partly due to their tissue specificity and lower expression levels compared with protein-coding genes. We compiled a comprehensive list of 18,517 lncRNAs from different sources and studied their expression profiles in 834 RNA-Seq samples from multiple inflammatory skin conditions and cytokine-stimulated keratinocytes. Applying a balanced random forest to predict involvement in biological functions, we achieved a median AUROC of 0.79 in 10-fold cross-validation, identifying significant DNA binding domains (DBDs) for 39 lncRNAs. G18244, a skin-expressing lncRNA predicted for IL-4/IL-13 signaling in keratinocytes, was highly correlated in expression with F13A1, a protein-coding gene involved in macrophage regulation, and we further identified a significant DBD in F13A1 for G18244. Reflecting clinical implications, AC090198.1 (predicted for IL-17 pathway) and AC005332.6 (predicted for IFN-γ pathway) had significant negative correlation with the SCORAD metric for atopic dermatitis. We also utilized single-cell RNA and spatial sequencing data to validate cell type specificity. Our research demonstrates lncRNAs have important immunological roles and can help prioritize their impact on inflammatory skin diseases.</p

τ\tauSPECT: A spin-flip loaded magnetic ultracold neutron trap for a determination of the neutron lifetime

The confinement of ultracold neutrons (UCNs) in a three dimensional magnetic field gradient trap allows for a measurement of the free neutron lifetime with superior control over spurious loss channels and can provide a large kinetic energy acceptance to enhance statistical sensitivity. In this paper, we present the first successful implementation of a pulsed spin-flip based loading scheme for a three-dimensional magnetic UCN trap. The measurements with the $\tau$SPECT experiment were performed at the pulsed UCN source of the research reactor TRIGA Mainz. We report on detailed investigations of major systematic effects influencing the neutron storage time, statistically limited by the size of the recorded data set. The extracted neutron storage time constant of $\tau = 859(16)\mathrm{s}$ is compatible with, but not to be interpreted as, a measurement of the free neutron lifetime.Comment: 15 pages, 19 figure

Accelerated discovery of two crystal structure types in a complex inorganic phase field

The discovery of new materials is hampered by the lack of efficient approaches to the exploration of both the large number of possible elemental compositions for such materials, and of the candidate structures at each composition1. For example, the discovery of inorganic extended solid structures has relied on knowledge of crystal chemistry coupled with time-consuming materials synthesis with systematically varied elemental ratios2,3. Computational methods have been developed to guide synthesis by predicting structures at specific compositions4,5,6 and predicting compositions for known crystal structures7,8, with notable successes9,10. However, the challenge of finding qualitatively new, experimentally realizable compounds, with crystal structures where the unit cell and the atom positions within it differ from known structures, remains for compositionally complex systems. Many valuable properties arise from substitution into known crystal structures, but materials discovery using this approach alone risks both missing best-in-class performance and attempting design with incomplete knowledge8,11. Here we report the experimental discovery of two structure types by computational identification of the region of a complex inorganic phase field that contains them. This is achieved by computing probe structures that capture the chemical and structural diversity of the system and whose energies can be ranked against combinations of currently known materials. Subsequent experimental exploration of the lowest-energy regions of the computed phase diagram affords two materials with previously unreported crystal structures featuring unusual structural motifs. This approach will accelerate the systematic discovery of new materials in complex compositional spaces by efficiently guiding synthesis and enhancing the predictive power of the computational tools through expansion of the knowledge base underpinning them

Corneal Epithelium Expresses a Variant of P2X7 Receptor in Health and Disease

Improper wound repair of the corneal epithelium can alter refraction of light resulting in impaired vision. We have shown that ATP is released after injury, activates purinergic receptor signaling pathways and plays a major role in wound closure. In many cells or tissues, ATP activates P2X7 receptors leading to cation fluxes and cytotoxicity. The corneal epithelium is an excellent model to study the expression of both the full-length P2X7 form (defined as the canonical receptor) and its truncated forms. When Ca2+ mobilization is induced by BzATP, a P2X7 agonist, it is attenuated in the presence of extracellular Mg2+ or Zn2+, negligible in the absence of extracellular Ca2+, and inhibited by the competitive P2X7 receptor inhibitor, A438079. BzATP enhanced phosphorylation of ERK. Together these responses indicate the presence of a canonical or full-length P2X7 receptor. In addition BzATP enhanced epithelial cell migration, and transfection with siRNA to the P2X7 receptor reduced cell migration. Furthermore, sustained activation did not induce dye uptake indicating the presence of truncated or variant forms that lack the ability to form large pores. Reverse transcription-polymerase chain reaction and Northern blot analysis revealed a P2X7 splice variant. Western blots identified a full-length and truncated form, and the expression pattern changed as cultures progressed from monolayer to stratified. Cross-linking gels demonstrated the presence of homo- and heterotrimers. We examined epithelium from age matched diabetic and non-diabetic corneas patients and detected a 4-fold increase in P2X7 mRNA from diabetic corneal epithelium compared to non-diabetic controls and an increased trend in expression of P2X7variant mRNA. Taken together, these data indicate that corneal epithelial cells express full-length and truncated forms of P2X7, which ultimately allows P2X7 to function as a multifaceted receptor that can mediate cell proliferation and migration or cell death

Single-cell sequencing reveals Hippo signaling as a driver of fibrosis in hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic inflammatory disease characterized by abscesses, nodules, dissecting/draining tunnels, and extensive fibrosis. Here, we integrate single-cell RNA sequencing, spatial transcriptomics, and immunostaining to provide an unprecedented view of the pathogenesis of chronic HS, characterizing the main cellular players and defining their interactions. We found a striking layering of the chronic HS infiltrate and identified the contribution of 2 fibroblast subtypes (SFRP4+ and CXCL13+) in orchestrating this compartmentalized immune response. We further demonstrated the central role of the Hippo pathway in promoting extensive fibrosis in HS and provided preclinical evidence that the profibrotic fibroblast response in HS can be modulated through inhibition of this pathway. These data provide insights into key aspects of HS pathogenesis with broad therapeutic implications.</p

Single-cell sequencing reveals Hippo signaling as a driver of fibrosis in hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic inflammatory disease characterized by abscesses, nodules, dissecting/draining tunnels, and extensive fibrosis. Here, we integrate single-cell RNA sequencing, spatial transcriptomics, and immunostaining to provide an unprecedented view of the pathogenesis of chronic HS, characterizing the main cellular players and defining their interactions. We found a striking layering of the chronic HS infiltrate and identified the contribution of 2 fibroblast subtypes (SFRP4+ and CXCL13+) in orchestrating this compartmentalized immune response. We further demonstrated the central role of the Hippo pathway in promoting extensive fibrosis in HS and provided preclinical evidence that the profibrotic fibroblast response in HS can be modulated through inhibition of this pathway. These data provide insights into key aspects of HS pathogenesis with broad therapeutic implications.</p