Investigation of microwave active elements embedded in composite structures

© 2016 IEEE. Multifunctional structures have become popular within the past decade as they allow for more efficient utilization of limited real-estate available on many civilian and military platforms. Taking structures and electromagnetics, one can marry these two fields to produce a weight optimized loadbearing microwave structure which may ideally be suited for unmanned aerial systems. This paper investigates the use of textile processes to develop loadbearing smart skins built into a class of structural conformal composite materials called pre-pregs (resin pre-impregnated fabrics). An example of an active UWB mini-circuits ERA-4SM+ (0-4 GHz) amplifier has been investigated within a 48 g.m-2 pre-preg structural glass material (HexPly914E). This amplifier has been embroidered and cured at 170°C in an autoclave at 700 kPa pressure. Its performance before and after curing has been examined

Microwave Doppler tomography of high impedance ground planes for aerospace applications

© 2016 IEEE. Recent developments in the areas of metamaterials and high impedance ground planes (HIGPs) have created new opportunities for the development of novel multi-functional aerospace materials. One niche application of such materials is the suppression of electromagnetic surface waves across the outer mold line (OML) of aerospace structures. Doppler tomographic imaging and spectral filtering techniques are used to characterize the performance of a simple numerically simulated HIGP. A tapered HIGP concept is introduced to improve the performance over a range of illumination angles. This tapered HIGP is to be embroidered in a commercial aerospace pre-preg material. Experimental results will be presented at the conference

Metamaterial-inspired electrically small antennas integrated into structural materials

© 2015 The Institute of Electronics, Information and Comm. An electrically small Egyptian axe dipole antenna has been designed and integrated into a glass fiber reinforced polymer (GFRP), a structural material now commonly found in most mobile platforms. The integration is accomplished by sewing the antenna with conductive threads into the GFRP prepreg and accounting for dimensional variations after curing under high temperature and pressure in an autoclave. The simulated and measured reflection coefficient values and radiated field patterns are in good agreement. These comparisons demonstrate that the antenna is nearly completely matched to the source without any matching circuit and radiates as an electric dipole

Multi-functional composite metamaterial-inspired EEAD antenna for structural applications

© 2016 IEEE. An electrically small, load-bearing Egyptian axe dipole (EAD) antenna has been sewn into a low loss, pure quartz glass composite material to investigate its performance. Previous investigations of embroidered Egyptian axe dipole antennas indicated that the dielectric losses of the associated epoxy-based composite, in conjunction with the high effective surface resistance of the conductive textile threads, significantly degrade their performance. Simulations of the EAD antenna using a composite sandwich structure based on an advanced embroidery technique and the much lower loss quartz fabric have shown that a realized gain of 0.9 dBi is possible, a dramatic improvement over previous realizations

Tomographic Characterization of a Multifunctional Composite High-Impedance Surface

© 1963-2012 IEEE. The performance of a multifunctional composite high-impedance surface (HIS) has been evaluated using the coherent Doppler tomography (CDT) and finite-impulse response (FIR) filtering techniques. A combination of embroidery and advanced laser manufacturing processes were used to fabricate the conformable multifunctional glass fiber reenforced polymer HIS. The CDT method was utilized because it enabled the generation of a high-resolution tomographic map of the HIS reflectivity. Tomograms generated at high incidence angles (>80° from normal) were used to localize and FIR filter unwanted scattering associated with the ground plane edges and HIS transition regions. The resulting scattered fields from a defect (metallic block positioned in the center of the tomogram) were then used to gain a significantly distinctive insight into the HIS scattering properties. Furthermore, unlike traditional methods for characterizing HISs, the CDT and FIR methods presented herein are applicable to electrically large and conformal HISs

Towards Carbon Based Artificial Impedance Surfaces for Conformal Aerospace Applications

© 2018 European Microwave Association. Conformal load-bearing smart skins (CLSS) provide the unique ability to integrate complex electrical systems into aerospace composite materials. This paper provides a preliminary investigation into the patterning of Artificial Impedance Surfaces (AIS) on these materials as they are well suited to develop conformal meta-surfaces (MTS). In particular, a composite veil material has been patterned using laser ablation and has been transferred directly onto a resin pre-impregnated (pre-preg) structural glass material. The new patterning technique was found suitable for the creation of fine geometric features with a resolution of approximately mathbf{100} mumathbf{m}. The material has been characterized by a reflected magnitude and phase measurement

A standardised sampling protocol for robust assessment of reach-scale fish community diversity in wadeable New Zealand streams

The New Zealand fish fauna contains species that are affected not only by river system connectivity, but also by catchment and local-scale changes in landcover, water quality and habitat quality. Consequently, native fish have potential as multi-scale bioindicators of human pressure on stream ecosystems, yet no standardised, repeatable and scientifically defensible methods currently exist for effectively quantifying their abundance or diversity in New Zealand stream reaches. Here we report on the testing of a back-pack electrofishing method, modified from that used by the United States Environmental Protection Agency, on a wide variety of wadeable stream reaches throughout New Zealand. Seventy-three first- to third-order stream reaches were fished with a single pass over 150-345 m length. Time taken to sample a reach using single-pass electrofishing ranged from 1-8 h. Species accumulation curves indicated that, irrespective of location, continuous sampling of 150 stream metres is required to accurately describe reach-scale fish species richness using this approach. Additional species detection beyond 150 m was rare (<10%) with a single additional species detected at only two out of the 17 reaches sampled beyond this distance. A positive relationship was also evident between species detection and area fished, although stream length rather than area appeared to be the better predictor. The method tested provides a standardised and repeatable approach for regional and/or national reporting on the state of New Zealand's freshwater fish communities and trends in richness and abundance over time

A temperature-controlled single-crystal growth cell for the in situ measurement and analysis of face-specific growth rates

The design and construction of a growth cell for the precision measurement of face-specific single-crystal growth rates are presented. Accurate mechanical drawings in SolidWorks of the cell and individual components are provided, together with relevant construction models. A general methodology for its use in the measurement of single-crystal growth rates and their underpinning growth mechanism is presented and illustrated with representative data provided for the crystal growth of the {011} and {001} faces of RS-ibuprofen single crystals grown in ethano­lic solutions. Analysis of these data highlights the utility of the methodology in morphological model development and crystallization process design

Co-Targeting PIM Kinase and PI3K/mTOR in NSCLC

PIM kinases are constitutively active proto-oncogenic serine/threonine kinases that play a role in cell cycle progression, metabolism, inflammation and drug resistance. PIM kinases interact with and stabilize p53, c-Myc and parallel signaling pathway PI3K/Akt. This study evaluated PIM kinase expression in NSCLC and in response to PI3K/mTOR inhibition. It investigated a novel preclinical PI3K/mTOR/PIM inhibitor (IBL-301) in vitro and in patient-derived NSCLC tumor tissues. Western blot analysis confirmed PIM1, PIM2 and PIM3 are expressed in NSCLC cell lines and PIM1 is a marker of poor prognosis in patients with NSCLC. IBL-301 decreased PIM1, c-Myc, pBAD and p4EBP1 (Thr37/46) and peIF4B (S406) protein levels in-vitro and MAP kinase, PI3K-Akt and JAK/STAT pathways in tumor tissue explants. IBL-301 significantly decreased secreted pro-inflammatory cytokine MCP-1. Altered mRNA expression, including activated PIM kinase and c-Myc, was identified in Apitolisib resistant cells (H1975GR) by an IL-6/STAT3 pathway array and validated by Western blot. H1975GR cells were more sensitive to IBL-301 than parent cells. A miRNA array identified a dysregulated miRNA signature of PI3K/mTOR drug resistance consisting of regulators of PIM kinase and c-Myc (miR17-5p, miR19b-3p, miR20a-5p, miR15b-5p, miR203a, miR-206). Our data provides a rationale for co-targeting PIM kinase and PI3K-mTOR to improve therapeutic response in NSCLC

Macrocyclic colibactin induces DNA double-strand breaks via copper-mediated oxidative cleavage.

Colibactin is an assumed human gut bacterial genotoxin, whose biosynthesis is linked to the clb genomic island that has a widespread distribution in pathogenic and commensal human enterobacteria. Colibactin-producing gut microbes promote colon tumour formation and enhance the progression of colorectal cancer via cellular senescence and death induced by DNA double-strand breaks (DSBs); however, the chemical basis that contributes to the pathogenesis at the molecular level has not been fully characterized. Here, we report the discovery of colibactin-645, a macrocyclic colibactin metabolite that recapitulates the previously assumed genotoxicity and cytotoxicity. Colibactin-645 shows strong DNA DSB activity in vitro and in human cell cultures via a unique copper-mediated oxidative mechanism. We also delineate a complete biosynthetic model for colibactin-645, which highlights a unique fate of the aminomalonate-building monomer in forming the C-terminal 5-hydroxy-4-oxazolecarboxylic acid moiety through the activities of both the polyketide synthase ClbO and the amidase ClbL. This work thus provides a molecular basis for colibactin's DNA DSB activity and facilitates further mechanistic study of colibactin-related colorectal cancer incidence and prevention