The Application of Auxetic Material for Protective Sports Apparel

Current research of auxetic materials highlights its potential as personal protective equipment for sports apparel with enhanced properties such as conformability, superior energy absorption and reduced thickness. In contrast, commercially available protective materials have proven to be problematic in that they inhibit movement, breathability, wicking and that molded pads are prone to saddling. Foam components are embedded within personal protective equipment for sports apparel, where protective material is positioned at regions of the body frequently exposed to injury of the soft tissue through collision, falls or hard impact. At present, the impact resistance of auxetic open cell polyurethane foam and some additively manufactured auxetic structures have been established, and processes for manufacturing curved auxetic materials as well as molding methods have been developed. Despite this, auxetic materials have not yet been applied as personal protective equipment for sports apparel in current research. This paper argues that there is scope to investigate auxetic materials potential for enhanced wearer functionality through properties of synclastic curvature and biaxial expansion

Fast Neutron Profiling with Imaging Plate (4) -Neutron Scattering Effects in Fast Neutron Imaging-

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Quasi-static characterisation and impact testing of auxetic foam for sports safety applications

This study compared low strain rate material properties and impact force attenuation of auxetic foam and the conventional open-cell polyurethane counterpart. This furthers our knowledge with regards to how best to apply these highly conformable and breathable auxetic foams to protective sports equipment. Cubes of auxetic foam measuring 150 x 150 x 150 mm were fabricated using a thermo-mechanical conversion process. Quasi-static compression confirmed the converted foam to be auxetic, prior to being sliced into 20 mm thick cuboid samples for further testing. Density, Poisson’s ratio and the stress-strain curve were all found to be dependent on the position of each cuboid from within the cube. Impact tests with a hemispherical drop hammer were performed for energies up to 6 J, on foams covered with a polypropylene sheet between 1 and 2 mm thick. Auxetic samples reduced peak force by ~10 times in comparison to the conventional foam. This work has shown further potential for auxetic foam to be applied to protective equipment, while identifying that improved fabrication methods are required

Applicability of a Bonner Shere technique for pulsed neutron in 120 GeV proton facility

The data on neutron spectra and intensity behind shielding are important for radiation safety design of high-energy accelerators since neutrons are capable of penetrating thick shielding and activating materials. Corresponding particle transport codes--that involve physics models of neutron and other particle production, transportation, and interaction--have been developed and used world-wide [1-8]. The results of these codes have been ensured through plenty of comparisons with experimental results taken in simple geometries. For neutron generation and transport, several related experiments have been performed to measure neutron spectra, attenuation length and reaction rates behind shielding walls of various thicknesses and materials in energy range up to several hundred of MeV [9-11]. The data have been used to benchmark--and modify if needed--the simulation modes and parameters in the codes, as well as the reference data for radiation safety design. To obtain such kind of data above several hundred of MeV, Japan-Fermi National Accelerator Laboratory (FNAL) collaboration for shielding experiments has been started in 2007, based on suggestion from the specialist meeting of shielding, Shielding Aspects of Target, Irradiation Facilities (SATIF), because of very limited data available in high-energy region (see, for example, [12]). As a part of this shielding experiment, a set of Bonner sphere (BS) was tested at the antiproton production target facility (pbar target station) at FNAL to obtain neutron spectra induced by a 120-GeV proton beam in concrete and iron shielding. Generally, utilization of an active detector around high-energy accelerators requires an improvement on its readout to overcome burst of secondary radiation since the accelerator delivers an intense beam to a target in a short period after relatively long acceleration period. In this paper, we employ BS for a spectrum measurement of neutrons that penetrate the shielding wall of the pbar target station in FNAL

Loss of ZBTB24 impairs nonhomologous end-joining and class-switch recombination in patients with ICF syndrome

The autosomal recessive immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome is a genetically heterogeneous disorder. Despite the identification of the underlying gene defects, it is unclear how mutations in any of the four known ICF genes cause a primary immunodeficiency. Here we demonstrate that loss of ZBTB24 in B cells from mice and ICF2 patients affects nonhomologous end-joining (NHEJ) during immunoglobulin class-switch recombination and consequently impairs immunoglobulin production and isotype balance. Mechanistically, we found that ZBTB24 associates with poly(ADP-ribose) polymerase 1 (PARP1) and stimulates its auto-poly(ADP-ribosyl)ation. The zinc-finger in ZBTB24 binds PARP1-associated poly(ADP-ribose) chains and mediates the PARP1-dependent recruitment of ZBTB24 to DNA breaks. Moreover, through its association with poly(ADP-ribose) chains, ZBTB24 protects them from degradation by poly(ADP-ribose) glycohydrolase (PARG). This facilitates the poly(ADP-ribose)-dependent assembly of the LIG4/XRCC4 complex at DNA breaks, thereby promoting error-free NHEJ. Thus, we uncover ZBTB24 as a regulator of PARP1-dependent NHEJ and class-switch recombination, providing a molecular basis for the immunodeficiency in ICF2 syndrome