Abstract Consistent with evidence of a strong correlation between interferon gamma (IFNγ) production and rabies virus (RABV) clearance from the CNS, we recently demonstrated that engineering a ...pathogenic RABV to express IFNγ highly attenuates the virus. Reasoning that IFNγ expression by RABV vaccines would enhance their safety and efficacy, we reverse-engineered two proven vaccine vectors, GAS and GASGAS, to express murine IFNγ. Mortality and morbidity were monitored during suckling mice infection, immunize/challenge experiments and mixed intracranial infections. We demonstrate that GASγ and GASγGAS are significantly attenuated in suckling mice compared to the GASGAS vaccine. GASγ better protects mice from lethal DRV4 RABV infection in both pre- and post-exposure experiments compared to GASGAS. Finally, GASγGAS reduces post-infection neurological sequelae, compared to control, during mixed intracranial infection with DRV4. These data show IFNγ expression by a vaccine vector can enhance its safety while increasing its efficacy as pre- and post-exposure treatment.
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•Three additive manufacturing parameter sets and five cellular materials.•Process-geometry-property interactions of the additively manufactured structures.•The intermediate power and ...exposure time parameter set results in less porosity.•The choice of cellular architectures has a greater influence on strength and energy absorption.
Additive Manufacturing (AM) has enabled the fabrication of metallic cellular materials that are of interest in the design of lightweight impact resistant structures. However, there is a need to understand the interactions between: (i) the material architecture, (ii) the AM process parameters, and (iii) the as-built geometry, microstructure and energy absorbing properties. In this work, we investigate the quasi-static and dynamic behaviour of cellular materials manufactured from 316L stainless steel using laser powder bed fusion (LPBF). Four cellular architectures are considered (octet lattice, lattice-walled square honeycomb, origami and square honeycomb), as well as three sets of AM process parameters, characterised by laser powers of 50, 125 and 200 W. The exposure time is adjusted to deliver the same total heat input. The 125 W case leads to material with the highest strength and ductility. The cellular materials with this process variant match their nominal densities most closely, and have the highest strength and energy absorption. Either reducing (50 W) or increasing (200 W) the power leads to a significant increase in porosity, reducing strength and energy absorption. However, we find that changes due to process-induced porosity have a smaller influence than those resulting from the choice of cellular architecture.
The significant degree of X-ray phase contrast created by air-tissue interfaces, coupled with the poor radiographic contrast of conventional chest radiographs, makes the inflated lung an ideal ...candidate for investigating the potential diagnostic improvement afforded by phase contrast X-ray imaging. In small animals these methods highlight the lung airways and lobe boundaries and reveal the lung tissue as a speckled intensity pattern not seen in other soft tissues. We have compared analyser-based and propagation-based phase contrast imaging modalities, together with conventional radiographic imaging, to ascertain which technique shows the greatest image enhancement for various lung sizes. The conventional radiographic image of a mouse was obtained on a Siemens Nova 3000 mammography system, whilst phase contrast images of mice and rabbit chests were acquired at the medical imaging beamline (20B2) at the SPring-8 synchrotron radiation research facility in Japan. For mice aged 1 day, 1 week and 1 month old it was determined that analyser-based imaging showed the greatest overall image contrast, however, for an adult rabbit both techniques yielded excellent contrast. The success of these methods in creating high quality images for rabbit lungs raises the possibility of improving human lung imaging using phase contrast techniques.
The mechanical response of the body centred cubic metal vanadium has been studied across a wide range of strain-rates through uniaxial stress compression. Samples of polycrystalline material have ...been tested up to strain-rates of 10
5
s
−1
using miniature split and direct impact Hopkinson bars. The strain-rate sensitivity of the yield strength is shown to be significant with an apparent increase around 10
2
–10
3
s
−1
and another increase ~ 10
5
s
−1
. This later increase is discussed as being consistent with uniaxial strain experiments and shown to compare favourably with a Preston-Tonks-Wallace model modified to fit data out to strain-rates of ~ 10
7
s
−1
. The benefits of the miniatured direct impact Hopkinson bar experiment are discussed along with the importance of velocimetry diagnostics and the requirement to understand and correct for friction at these high rates. Multiple repeat experiments and comparison of data taken with different loading platforms and different sample sizes are shown to produce a consistent and reliable data set which is complementary to existing sparse data on vanadium.
This research investigates whether the layup order of the carbon-fibre/glass-fibre skins in hybrid composite sandwich panels has an effect on impact response. Composite sandwich panels with ...carbon-fibre/glass-fibre hybrid skins were subjected to impact at velocities of 75 ± 3 and 90 ± 3 m s
−1
. Measurements of the sandwich panels were made using high-speed 3D digital image correlation (DIC), and post-impact damage was assessed by sectioning the sandwich panels. It was concluded that the introduction of glass-fibre layers into carbon-fibre laminate skins reduces brittle failure compared to a sandwich panel with carbon-fibre reinforced polymer skins alone. Furthermore, if the impact surface is known, it would be beneficial to select an asymmetrical panel such as Hybrid-(GCFGC) utilising glass-fibre layers in compression and carbon-fibre layers in tension. This hybrid sandwich panel achieves a specific deflection of 0.322 mm kg
−1
m
2
and specific strain of 0.077% kg
−1
m
2
under an impact velocity of 75 ± 3 m s
−1
. However, if the impact surface is not known, selection of a panel with a symmetric yet more dispersed hybridisation would be effective. By distributing the different fibre layers more evenly within the skin, less surface and core damage is achieved. The distributed hybrid investigated in this research, Hybrid-(GCGFGCG), achieved a specific deflection of 0.394 mm kg
−1
m
2
and specific strain of 0.085% kg
−1
m
2
under an impact velocity of 75 ± 3 m s
−1
. Blast loading was performed on a large scale version of Hybrid-(GCFGC) and it exhibited a maximum deflection of 75 mm following a similar deflection profile to those observed for the impact experiments.
Sea turtles migrate thousands of miles annually between foraging and breeding areas, carrying dozens of epibiont species with them on their journeys. Most sea turtle epibiont studies have focused on ...large-sized organisms, those visible to the naked eye. Here, we report previously undocumented levels of epibiont abundance and biodiversity for loggerhead sea turtles (Caretta caretta), by focusing on the microscopic meiofauna. During the peak of the 2018 loggerhead nesting season at St. George Island, Florida, USA, we sampled all epibionts from 24 carapaces. From the subsamples, we identified 38,874 meiofauna individuals belonging to 20 higher taxa. This means 810,753 individuals were recovered in our survey, with an average of 33,781 individuals per carapace. Of 6992 identified nematodes, 111 different genera were observed. To our knowledge, such levels of sea turtle epibiont abundance and diversity have never been recorded. Loggerhead carapaces are without doubt hotspots of meiofaunal and nematode diversity, especially compared to other non-sedimentary substrates. The posterior carapace sections harbored higher diversity and evenness compared to the anterior and middle sections, suggesting increased colonization and potentially facilitation favoring posterior carapace epibiosis, or increased disturbance on the anterior and middle carapace sections. Our findings also shed new light on the meiofauna paradox: “How do small, benthic meiofauna organisms become cosmopolitan over large geographic ranges?” Considering high loggerhead epibiont colonization, the large distances loggerheads migrate for reproduction and feeding, and the evolutionary age and sheer numbers of sea turtles worldwide, potentially large-scale exchange and dispersal for meiofauna through phoresis is implied. We distinguished different groups of loggerhead carapaces based on divergent epibiont communities, suggesting distinct epibiont colonization processes. These epibiont observations hold potential for investigating loggerhead movements and, hence, their conservation.
Protecting structures from the effect of blast loads requires the careful design of all building components. In this context, the mechanical properties of Polyvinyl Butyral (PVB) are of interest to ...designers as the membrane behaviour will affect the performance of laminated glass glazing when loaded by explosion pressure waves. This polymer behaves in a complex manner and is difficult to model over the wide range of strain rates relevant to blast analysis. In this study, data from experimental tests conducted at strain rates from 0.01 s
−1
to 400 s
−1
were used to develop material models accounting for the rate dependency of the material. Firstly, two models were derived assuming Prony series formulations. A reduced polynomial spring and a spring derived from the model proposed by Hoo Fatt and Ouyang were used. Two fits were produced for each of these models, one for low rate cases, up to 8 s
−1
, and one for high rate cases, from 20 s
−1
. Afterwards, a single model representing all rates was produced using a finite deformation viscoelastic model. This assumed two hyperelastic springs in parallel, one of which was in series with a non-linear damper. The results were compared with the experimental results, assessing the quality of the fits in the strain range of interest for blast loading situations. This should provide designers with the information to choose between the available models depending on their design needs.
Austenitic stainless steels are susceptible to stress corrosion cracking (SCC) when exposed to chloride ions and tensile stresses. For laser powder bed fusion (LPBF) components, high residual tensile ...stresses exist from the large thermal gradients during solidification. While post fabrication heat treatments can relieve residual stresses, their effectiveness in improving SCC resistance of LPBF material is undetermined. The effects of different heat treatments (i.e. temperature and cooling method) and build orientations on SCC susceptibility of LPBF 316L were explored. Samples were exposed to MgCl2 and maintained at 75 °C and 70% RH for the test duration. Cracks were highly branched and propagated perpendicularly to build direction even in the presence of an applied perpendicular 60 MPa stress. Vertical as-built specimens exhibited higher cracking densities than horizontal ones, due to higher surface residual stresses. SCC and corrosion favoured one side for horizontal specimens while the distribution was random for vertical specimens. After 750 °C (2 h, furnace cooled) heat treatment, SCC susceptibility reduced for vertical 316L but increased for horizontal 316L. This was attributed to competing effects: reduction in residual surface tensile stresses (beneficial) and loss of non-equilibrium microstructure (detrimental). Encapsulation to prevent oxidation during heat treatment negatively impacted SCC resistance of LPBF 316L, likely due to changes to surface oxide condition. No SCC was observed after 900 °C (0.5 h) heat treatments within the test duration, however, pitting corrosion persisted.
Background Chronic heart failure is one of a number of disorders associated with the development of a wasting syndrome. The precise mechanisms of this remain unknown, but previous studies have ...suggested a role for immune and neurohormonal factors. Methods We aimed to investigate in detail the differences in body composition (dual X-ray absorptiometry) and the relationship to candidate biochemical factors of the immune, neurohormonal and metabolic systems in 15 healthy controls, 36 stable non-cachectic and 18 cachectic patients with chronic heart failure. Results Non-cachectic patients showed reduced leg lean tissue (−9·1%,P<0·01) compared to controls. Cachectic patients had significantly reduced lean (−21·0% vs controls, −19·9% vs non-cachectics), fat (−33·0% vs controls, −37·0% vs non-cachectics) and bone tissue (−17·5% vs controls, −15·9% vs non-cachectics) (allP<0·0001). Cachectic patients showed a significantly increased cortisol/dehydroepiandrosterone ratio (+203% vs controls,P<0·0001; +89% vs non-cachectics,P=0·0011) and increased cytokine levels (TNF-α, soluble TNF-receptor 1, interleukin-6). The levels of catabolic hormones and cytokines correlated significantly with reduced muscle and fat tissue content and reduced bone mass. Conclusion Peripheral loss of muscle tissue is a general finding in chronic heart failure. The wasting in cardiac cachexia affects all tissue compartments and is significantly related to neurohormonal and immunological abnormalities.
Abstract Background Deep neck flexor (DNF) muscles stabilize the neck and contribute to head acceleration control. The function of DNF in cervical spine dynamic stabilization has not been examined in ...athletes of any age group, including adolescents. This investigation was necessary prior to studying the DNF muscles’ role in cervical spine injury patterns. Objectives (1) To determine average Deep Neck Flexor Endurance Test (DNFET) time scores in high school and university-aged subjects (ages 14-22); and (2) To establish the relationship between gender and age for adolescent DNFET time scores. Design Cross-Sectional Design. Setting Public High School and Private University. Participants 81 (40 males, 41 females) healthy high school and collegiate athletes. Intervention DNFET time scores (in seconds) were collected and means values were calculated. Inter-rater reliability was established using the first 15 university-aged subjects enrolled in the study. Main Outcomes Mean DNFET time (seconds) scores. Results Deep Neck Flexor (DNF) muscle endurance inter-rater reliability coefficient of reproducibility for 4 allied health clinicians was ICC (2,4) 0.712 (confidence interval, 0.24-0.85). The mean (SD) DNFET time score for females was 31.86 (±8.53) seconds versus 35.57 (±10.43) seconds for males. The DNFET performance demonstrated a significant but fair correlation with age (r = 0.401, p= .0001). No significant performance differences were found between male and female subjects in the 14-17yo ( U = 187.0, p = .285), 18-22yo subjects ( U = 145.0, p = .215), or total male versus female subject groups ( U = 653.0, p = .083). Conclusion Our study establishes a normative data set available for the DNFET in the adolescent population. The fair correlation between DNFET time scores and age is consistent with other studies. These findings serve as a basis for clinician testing, objectifying and monitoring DNF dysfunction in an adolescent athletic population.
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