Out-of-plane auxeticity in sintered fibre network mats

Fibre network mats composed of stainless steel exhibit an unusually large out-of-plane auxeticity (i.e. high negative Poisson’s ratio ν) when subjected to in-plane tensile loading. In situ observations in a scanning electron microscope suggest that this is attributable to fibre segment straightening. An investigation was carried out on the effects of fibre volume fraction and network thickness on the auxetic response. Weak inter-layer bonding, high fibre content and low network thickness were found to amplify the auxetic effect.This research was supported by the European Research Council (ERC) (Grant No. 240446). We wish to thank Dr. Kalin Dragnevski at The Laboratory for In situ Microscopy and Analysis (LIMA) in the Department of Engineering Science, Oxford University for the help in setting up the in situ DEBEN experiments.This is the accepted manuscript of a paper published in Scripta Materialia (Neelakantan S, Tan J-C, Markaki AE, Scripta Materialia, 2015, doi:10.1016/j.scriptamat.2015.04.028). The final version is available at http://dx.doi.org/10.1016/j.scriptamat.2015.04.02

Planes of isotropic Poisson's ratio in anisotropic crystalline solids

It is shown that loading directions can exist in all single crystals for which Poisson’s ratio is isotropic in the plane transverse to the loading direction. The body diagonals and the cube axes of cubic crystals, the four-fold axis in tetragonal crystals and the six-fold axis in hexagonal crystals are examples of such loading directions. However, these loading directions do not necessarily just lie only along high rotational symmetry axes. A new three-dimensional “anisotropy surface” is introduced to represent the degree of anisotropy of the Poisson’s ratio within the plane normal to a loading direction for a particular choice of single crystal.This work is part of the Early Career Research (ECR) grant award (Ref. no.: ECR/2016/001953) funded by Science and Engineering Research Board (SERB) of Department of Science and Technology (DST), India. Dr. Suresh Neelakantan acknowledges the support

Recombinant factorVIII Fc fusion protein for the prevention and treatment of bleeding in children with severe hemophilia A

This work was supported by funding from Biogen, including funding for the editorial and writing support in the the development of this paper

Cell structure, stiffness and permeability of freeze-dried collagen scaffolds in dry and hydrated states.

UNLABELLED: Scaffolds for tissue engineering applications should be highly permeable to support mass transfer requirements while providing a 3-D template for the encapsulated biological cells. High porosity and cell interconnectivity result in highly compliant scaffolds. Overstraining occurs easily with such compliant materials and can produce misleading results. In this paper, the cell structure of freeze-dried collagen scaffolds, in both dry and hydrated states, was characterised using X-ray tomography and 2-photon confocal microscopy respectively. Measurements have been made of the scaffold's Young's modulus using conventional mechanical testing and a customised see-saw testing configuration. Specific permeability was measured under constant pressure gradient and compared with predictions. The collagen scaffolds investigated here have a coarse cell size (∼100-150 μm) and extensive connectivity between adjacent cells (∼10-30 μm) in both dry and hydrated states. The Young's modulus is very low, of the order of 10 kPa when dry and 1 kPa when hydrated. There is only a single previous study concerning the specific permeability of (hydrated) collagen scaffolds, despite its importance in nutrient diffusion, waste removal and cell migration. The experimentally measured value reported here (5 × 10(-)(10)m(2)) is in good agreement with predictions based on Computational Fluid Dynamics simulation and broadly consistent with the Carman-Kozeny empirical estimate. It is however about three orders of magnitude higher than the single previously-reported value and this discrepancy is attributed at least partly to the high pressure gradient imposed in the previous study. STATEMENT OF SIGNIFICANCE: The high porosity and interconnectivity of tissue engineering scaffolds result in highly compliant structures (ie large deflections under low applied loads). Characterisation is essential if these scaffolds are to be systematically optimised. Scaffold overstraining during characterisation can lead to misleading results. In this study, the stiffness (in dry and hydrated states) and specific permeability of freeze-dried collagen scaffolds have been measured using techniques customised for low stiffness structures. The scaffold cell structure is investigated using X-ray computed tomography, which has been applied previously to visualise such materials, without extracting any structural parameters or simulating fluid flow. These are carried out in this work. 2-photon confocal microscopy is used for the first time to study the structure in hydrated state.This research was supported by the European Research Council (Grant No. 240446) and the EPSRC (EP/E025862/1). Financial support for MCV and RAB has been provided via the WD Armstrong studentship and the National Institute for Health Research (NIHR), respectively.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.actbio.2016.01.04

Analysis of τ-mesons

We describe in this paper measurements made on the decay products of 11 τ-mesons observed in large nuclear emulsion block detectors. Out of the 33 charged decay products; 27 have been arrested in the block, and were identified as π-mesons. The charge of the τ-meson was found to be positive in 6 cases. In one case the charge of the τ-meson is possibly negative and in 4 cases it could not be determined. Omitting one τ-meson in which a high energy γ-ray is emitted and which has been reported earlier the weighted mean Q-value of the remaining 10 τ-mesons is: Qτ = 76.3 ± 0.3MeV which gives the mass of the τ -meson as: mτ =968.7 ± 0.6me This value is slightly higher than the mean value 965.5 ± 0.7m e compiled by Amaldiet al. from measurements of various laboratories

Chemical investigation of indian lichens Part XX. A new synthesis of teloschistin

This article does not have an abstract

Chemical investigation of Indian lichens. Part XI. Constitution of Teloschistin - The position of the methoxyl group

This article does not have an abstract

A synthesis of stillopsidin and its methyl ethers

This article does not have an abstract

Landscape Connectivity For Wildlife and Water: The State of the Literature

Purpose of Review: The science of landscape connectivity is widely applied to identify corridors for wildlife movement through unprotected areas. Where corridors coincide with forested or vegetated headwater catchments, they can contribute to blue water security for downstream users and recycle precipitation through green water flux to the larger region. This review examines the extent to which hydrology is recognized within studies on wildlife corridors. We illustrate the synergy between wildlife corridors and water security in the Central Indian Highlands, a globally important region for tiger (Panthera tigris) conservation and the water tower for five major rivers. Recent Findings: We find that a growing but still minor component of the literature on landscape connectivity addresses hydrology. Out of 127 publications on landscape connectivity that address both hydrology and wildlife, 50% were published after 2015 and hydrology-related words appear more frequently in abstracts over time (27% in 1993–2003 and 45% in 2014–2023 of most frequently used words) The case study illustrates potential synergies for water security and conservation, with areas for wildlife connectivity twice as rugged, three times more forested, and about 1.8 times denser with small streams than other areas in the landscape. About half of the area identified for landscape connectivity overlaps with catchment areas for five major dams. Summary: Freshwater resources and water security are vital in human-dominated landscapes such as central India. A holistic view of landscape connectivity beyond wildlife provides practitioners with additional rationale for conserving these areas to maintain water resources that are directly relevant to people living in the landscape

Root canal irrigants influence the hydrophobicity and adherence of Staphylococcus epidermidis to root canal dentin: an in vitro study

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