In this study, the extreme tension wave front profile (pull speed up to 1.6 km/s) in pure aluminum (density 2.7 g/cm3 ) is analyzed using the LAMMPS molecular dynamics (MD) code and based on the tension conservation equations of mass, momentum, and energy. The simulation results agree favorably with the theoretical calculation. The profile of the extreme tension wave front is observed from the MD code simulation, and a typical shockless ramp wave front formation is identified during forced extreme tension loading. Further analysis was accomplished based on the formation of the ramp wave front, illustrating the behavior of the isentrope of aluminum under extreme tension loading.

The use of organically modified clays as nano-reinforcement in polymer matrices is widely investigated owing to their remarkable reinforcement at low filler loading. In this body of work, the nanocomposites were prepared by melt blending nanoclay with polyamide 11 (PA 11) utilising a twin-screw extruder in order to maximise the dispersion of clay particles within the matrix during compounding. The main aim of the work was to study the reinforcing effect of nanoclay within PA 11 using two micromechanical model namely Halpin-Tsai and Mori-Tanaka composite theories. These theories were used to predict the effective tensile modulus of PA 11 nanocomposites and the results were compared to the experimental data. In addition, the Halpin-Tsai model was used to predict the storage modulus and heat distortion temperature (HDT) of PA 11 nanocomposites. It was found that the tensile modulus for nanocomposites with a high clay aspect ratio exhibits up to 10% higher when compared to the nanocomposites with lower clay aspect ratio. Thus, it is believed that the combination of clay aspect ratio and modulus contributes to the super reinforcing effect of nanoclay within the PA 11 matrix.

Engineering of self-disinfecting surfaces to constrain the spread of SARS-CoV-2 is a challenging task for the scientific community because the human coronavirus spreads through respiratory droplets. Titania (TiO2) nanocomposite antimicrobial coatings is one of the ideal remedies to disinfect pathogens (virus, bacteria, fungi) from common surfaces under light illumination. The photocatalytic disinfection efficiency of recent TiO2 nanocomposite antimicrobial coatings for surfaces, dental and orthopaedic implants are emphasized in this review. Mostly, inorganic metals (e.g. copper (Cu), silver (Ag), manganese (Mn), etc), non-metals (e.g. fluorine (F), calcium (Ca), phosphorus (P)) and two-dimensional materials (e.g. MXenes, MOF, graphdiyne) were incorporated with TiO2 to regulate the charge transfer mechanism, surface porosity, crystallinity, and the microbial disinfection efficiency. The antimicrobial activity of TiO2 coatings was evaluated against the most crucial pathogenic microbes such as Escherichia coli, methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Legionella pneumophila, Staphylococcus aureus, Streptococcus mutans, T2 bacteriophage, H1N1, HCoV-NL63, vesicular stomatitis virus, bovine coronavirus. Silane functionalizing agents and polymers were used to coat the titanium (Ti) metal implants to introduce superhydrophobic features to avoid microbial adhesion. TiO2 nanocomposite coatings in dental and orthopaedic metal implants disclosed exceptional bio-corrosion resistance, durability, biocompatibility, bone-formation capability, and long-term antimicrobial efficiency. Moreover, the commercial trend, techno-economics, challenges, and prospects of antimicrobial nanocomposite coatings are also discussed briefly.

The Irish Government has identified research and development (R&D) and innovation as among the key pillars of growth within the economy. To achieve this growth, R&D tax incentives, which are adopted in advanced economies, are set into policy to encourage firms to innovate, thus, making companies more competitive and productive. One of the key enablers to driving R&D is a well-designed, competitive and sustainable tax policy to support the activity. However, evidence on the effectiveness of R&D tax incentives for innovation is largely anecdotal and the influence of innovation on firm-level taxation is still underexplored, in terms of and empirical examination. This paper sets out to review the recent trends and views of industry regarding R&D tax credits.

The addition of nanoclay within polymer matrix is anticipate to enhance the properties of the polymer system. Nonetheless, one of the key elements in property enhancements of a polymer nanocomposites is the surface modifications of the nanoclay. This is due to the affinity between polymer matrix and nanoclay is of important factors should be considered. In this study, amorphous polyamide were melt blended with different nanoclay grades with different surface modifications in order to evaluate the best clay grade for the polymer system. The thermal analysis carried out on the amorphous polyamide nanocomposites were carried out by means of differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) whereas the mechanical properties were investigated using tensile testing. It was observed that there were changes in the glass transition temperature (Tg) of the nanocomposites due to clay additions. Further, the storage modulus was found to increase as a result of nanoclay incorporation. The type of clay grades significantly affects the mechanical properties of the amorphous polyamide nanocomposites.

Owing to the exceptional properties of graphene and the crucial role of substrate on the performance of electrochemical biosensors, several graphene-based hybrid structures have recently emerged, yielding improved selectivity and sensitivity. To date, most of the reported biosensors utilize solution-driven graphene flakes with drawbacks of low conductivity (due to high inter-junction contact resistant) and structural fragility. Herein, we present a conductive three-dimensional CeO2 semiconductor nanoparticles/graphene nanocomposite, as a platform for sensitive detection of hydrogen peroxide, an important molecule in fundamental biological processes. The 3D conductive graphene architecture is fabricated by chemical vapor deposition on nickel foam. The fabricated biosensor displays high sensitivity (60 mu A.mM(-1)) at a low negative potential of -0.25 V, a low detection limit (<1.0 mu M at S/N = 3), and a fast response (<5 s) in the range of 2.8 to 160 mu M. Furthermore, density functional theory simulations show that the improved detection is not only related to the catalytic effect of ceria nanoparticles, but also to more efficient charge transfer from nanoparticles to the 3D graphene network. Moreover, it is established that the amperometric response of the biosensor is insensitive to interfering molecules such as glucose, sucrose, and potassium chloride, indicating its potential for practical applications. (C) The Author(s) 2019. Published by ECS.

Dielectric nanocomposite elastomers based on poly(styrene-ethylene/butylene-styrene) (SEBS) and SEBS-grafted-maleic anhydride (SEBS-g-MA) with barium titanate (BT) suitable for electroactive applications were successfully manufactured by using two corotating twin extrusion systems. The main purpose of the work was to investigate the thermal, mechanical, dielectric, and morphological effects of additives on SEBS and SEBS-g-MA to widen their applications for electroactive applications using fast and more cost-effective simple production process. The morphological characterization showed a good and bad dispersion of BT into SEBS-g-MA and SEBS with 34.9% and −3% dielectric permittivity change in SEBS-g-MA and SEBS upon addition of 10 wt% BT. In addition, dielectric permittivity change, thermal change (enthalpy relaxation and thermal transitions), and mechanical (Young’s modulus, hysteresis loss under multiple stress cycles, storage modulus, loss modulus, and tan δ) properties of elastomers were found to be a function of additive concentration, compatibility and interaction between elastomers and additive type, orientation of additives, and reinforcing factors of additives in elastomers. A simple and effective modeling technique was used to demonstrate the effects of dielectric properties on nanocomposites due to poor dispersion of additives.

The problem of dispersion of nano-additives in thermoplastic elastomers using continuous processing techniques still prevails in scientific and engineering applications. To address this, supercritical fluid (SCF) assisted extrusion was utilised to develop elastic, isotropic and electrically superior materials, which contain elastomeric microphases of Poly(styrene-ethylene-butylene-styrene [SEBS] with homogeneously dispersed conductive nano additives of carbon black [CB]. SEBS-SCF/CB 5 wt% extrudates showed 46% and 14% higher storage modulus compared to their counterparts in transverse and longitudinal direction respectively. Similarly, piezo-resistive properties of SEBS-SCF/CB composites were found to have a superior strain gauge factor with linear decrease in conductivity with increasing strain, compared to nonlinear increase/decrease in piezoresistive behaviour of SEBS/CB composites. Piezo-resistivity of SEBS-SCF/CB 5 wt% nanocomposites were found to be highly sensitive in both bending (3.6% change in resistance per degree for 1.7 cm thick sample) and tensile strain conditions (gauge factor ca. 9) for smart applications.

Silver and silver nanoparticles (AgNPs) exhibit antimicrobial properties against some bacteria, fungi and viruses, however, the ever-increasing application of nanosilver in consumer products, water disinfection and healthcare settings, have raised concerns over the public health/environmental safety of this nano material. The current ubiquity of nanosilver may result in repeated exposure through various routes (skin, inhalation, or ingestion) which may lead to health complications. While there are a number of review articles and case studies published to date on the subject, an updated coherent review that clearly delineates thresholds and safe doses is lacking. Thus, it is plausible to have an overview of the most recent findings on the threshold limits, safe doses of silver and its related nanoscale forms, and the needed actions to ensure the safety and health of human, terrestrial and aquatic lives. This review provides an account of the effects of nanosilver in our daily lives. Statement of Significance This manuscripts is a review of the toxicity of nanosized silver. With respect to the existing literature, it goes beyond stating that there is a knowledge gap, drawing the attention of a wider readership to the ever-growing evidence of nanosilver toxicity to human and nature, and outlining the dose thresholds based on comprehensive data mining and visualisation. There are nearly 500 consumer products that claim to contain nanosilver. Thus, we trust a review of recent conclusive findings is timely. This manuscript is in line with the scope of the Journal, enabling a better understanding of the biological response to a widely-used bionanomaterial. Moreover, it provides a bigger picture of the link between surface properties and biocompatibility of nanosilver in different forms. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Biomedical polymers are an integral component in a wide range of medical devices because of their many desirable properties. However, extensive use of polymer materials in medical devices has been associated with an increasing incidence of patient infections. Efforts to address this issue have included incorporating antimicrobial additives to develop novel antimicrobial polymeric materials. Silver, with its high toxicity towards bacteria, oligodynamic effect and good thermal stability, has been employed as an additive for polymeric medical devices. In the present study, commercially available elemental (Biogate) and ionic (Ultrafresh 16) silver additives were incorporated into a Polyamide 11 (PA 11) matrix using a compression press. These polymer composites were evaluated for their antimicrobial and ion-release properties. Elemental silver composites were shown to retain their antimicrobial properties for extended periods and actively released silver ions for 84 days; whereas ionic silver composites lost their ion-release activity and, therefore, their antibacterial activity after 56 days. Bacterial log reduction units of 3.87 for ionic silver and 2.41 for elemental silver were identified within 24 h, when tested in accordance with the ISO 22196 test standard; this indicates that ionic silver is more efficient for short-term applications than elemental silver.

Embolus Analogues (EAs) can provide understanding of the mechanical characteristics of blood clots of cardiac origin. Bovine EAs (n = 29) were fabricated with varying concentrations of thrombin (0–20 NIHU/ml blood). Histological staining confirmed that EA composition compared sufficiently with human samples reported in literature. EAs were mechanically described under seven testing conditions: tensile, compression, shear wave ultrasound elastography (SWE), parallel plate rheometry, indentation, creep and relaxation. The Young modulus of bovine EAs in tension varied from 7 kPa (5% strain) to 84 kPa (50% strain). The compressive Young modulus increased with increasing thrombin concentration, which was in agreement with the SWE results. There was no significant difference in Young modulus throughout the clot (p < 0.05). The EAs displayed a non-linear response under parallel plate rheometry, creep and stress relaxation. The 3rd order Mooney–Rivlin constitutive equation and Standard Linear Solid model were used to fit the non-linear stress–strain response and time-dependent properties, respectively. This is the first study in which bovine EAs, with and without addition of thrombin, are histologically and mechanically described with corresponding proposed constitutive equations. The equations and experimental data determined can be applied for future numerical and experimental testing of mammalian EAs and cardiac source clots.

Tapered Fiber Optic Sensors (TFOS) are typically interrogated using an Optical Spectrum Analyzer (OSA) or a spectrometer. As a result, multiple TFOS with similar operating wavelengths cannot be interrogated simultaneously. This paper is an extension to the previously published work on “Interrogation of Fiber Bragg Grating Arrays by Illumination using a Low Coherence Interferogram” [1]. In this paper, the ability of the system to simultaneously interrogate multiple TFOS in a single interferometric scan is demonstrated. Varying concentrations of glucose solutions were used to determine the system's sensing capability. Of the two TFOS used, the one with the larger FSR was found to yield a linear resolution of ~ 2.96e-3ΔRad/1000ppm and the other sensor with a smaller FSR yielded a linear resolution of ~ 5.23e-3ΔRad/1000ppm.

This study investigates the effect of supercritical fluid carbon dioxide (scCO(2)) assisted extrusion on the thermal, mechanical, electrical, and morphological properties of microphase separated Poly(styrene-ethylene/butylene-styrene) [SEBS] triblock at various critical pressures. Thermal degradation analysis reveals 50 degrees C enhancement in thermal stability of SEBS when extruded with scCO(2) compared to SEBS extruded without scCO(2). Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) show improved phase separation due to the breakdown of domain size between the hard and soft block and damping losses represented by tan delta. It was found that SEBS processed with scCO(2) has low elastic modulus because of foaming as well as restructuring of hard phase around the soft component. Fourier Transform Infrared Spectroscopy (FTIR) shows the interaction of scCO(2) in aromatic phenyl rings of S-rich domain in SEBS. Dielectric spectroscopy analysis also confirms scCO(2) results in the difference in relaxation of soft and hard blocks within triblock.

The melt-extrusion process is utilized in the pharmaceutical arena for the manufacturing of a variety of dosage forms and formulations, including solid dispersions. This technology is considered an efficient and continuous dosage form manufacturing method. However, there are potential challenges mainly because, during hot-melt extrusion, polymers are subject to mechanical and thermal degradation. Mechanical degradation may be induced by the shear effects imposed by the rotating screw. Thermal degradation results from high temperatures and includes random scission, scission from the ends of the polymer and unzipping of substitute groups. This paper endeavors to understand the impact of thermal and/or mechanical components of the melt-extrusion process on the stability of a pH sensitive polymer, namely Shellac. Correlation between the screw speeds and processing temperature profile was examined in the context of the overall degradation profile of the polymer. The results suggest that the processing stability of Shellac was reliant on optimization of screw speed (rpm) and process temperature.

The aim of this study was to develop microspheres as a drug delivery system using natural polymeric materials including Alginate and Chitosan using an Ionotropic Gelation method of synthesis. In this study, several parameters which affect the functionality of the microspheres were examined. They include; the concentrations of Chitosan, Sodium Alginate, Calcium Chloride, and the pH value of the gelation medium. The effect of these parameters on the product were determined by observing the morphology of microspheres using light microscopy and Scanning Electron Microscopy (SEM). Overall, the Chitosan-Alginate microspheres were successfully prepared with using a Chitosan concentration at 0.25% w/v, Sodium Alginate and Calcium Chloride concentration of between 4% to 6% w/v.

Direct incorporation of antimicrobial additive into the polymer matrix is a cost effective approach for the development of polymer/metal antimicrobial composites. Application of these antimicrobial composite systems for manufacturing medical devices addresses the issue of device related infections. In the present study, commercially available inorganic copper based additive, Plasticopper, was incorporated into a Polyamide 11(PA 11) matrix during the polymer processing stage. These polymer composites were evaluated for their morphological, mechanical, antimicrobial and ion release properties. Isothermal crystallisation studies showed that the copper additive acted as a nucleating agent and promoted faster crystallisation. Short term mechanical studies confirmed that the incorporation of copper has reinforcing effect on the composites with 5 and 10% copper loadings and did not adversely affect the short-term mechanical performance of the polymer composites. These composite systems were shown to be active against Escherichia coli ATCC 8739 with > 99.99% reduction in bacterial population. Corresponding ion release profiles for these composites indicated long term antimicrobial activity.

Hot melt extrusion (HME) is considered an efficient technique in developing solid molecular dispersions, and has been demonstrated to provide sustained, modified and targeted drug delivery resulting in improved bioavailability. However, most commercial enteric or pH-responsive polymers are relatively difficult to process or have high Glass Transition Temperature (Tg) values, making their use with temperature-sensitive drugs, probiotics or biologics not viable. Shellac is a natural thermoplastic, and after a review of current literature on the pharmaceutical HME process, a possible gap in the knowledge of the use of shellac to produce dosage forms by means of HME was identified. This work explores the possibility of SSB® 55 pharmaceutical-grade shellac as a melt-extrudable encapsulation polymer to entrap freeze-dried probiotic powder and to determine bacterial cell viability post-processing. Well-defined strands were produced from the physical mixture of shellac and Biocare® Bifidobacterium Probiotic. FTIR clarified that there are no significant interactions between the probiotic and polymer. All of the samples demonstrated less than 5% degradation over 24 h at pH of both 1.2 and 6.8. At pH 7.4, both loaded samples gave a similar dissolution trend with complete degradation achieved after 10–11 h. Following five-month storage, 57.8% reduction in viability was observed.

Technologies that can increase crop production while maintaining low pollution are essential for sustainable agriculture. This study compares the germination performance of Durum wheat seeds (Triticum durum Desf.) which were coated with synthetic coatings [polyacrylamide (PA)] and novel natural coatings [mixtures of agar/ι-carrageenan (AC)] at different moisture levels. A number of germination performance indicators were measured for each of the categories of coatings. These included: (i) % germination, (ii) radicle emergence, (iii) speed of germination, (iv) seedling length, (v) fresh seed weight and (vi) seed vigour index. Results showed that both the synthetic and natural coatings improved germination performance in the Durum wheat seeds versus the untreated seeds when non-drought (80% moisture) conditions were used. However, when 40% moisture levels were used, the natural coated seeds showed a 6% improvement in germination performance over the synthetic PA coated seeds. This improved germination performance under drought stress along with the fact that these novel AC coatings used are completely natural and environmentally friendly suggests that these novel coatings have a big future in seed coatings, especially in countries which experience drought conditions and are dependent on natural irrigation.

Objectives: To examine the effect of prolonged standing on gluteus medius coactivation and to observe whether the changes in gluteus medius coactivation over time were related to the development of low back pain in elite female field hockey players.Design: Prospective cohort design.Methods: Participants were 39 elite female field hockey players (14 with a history of low back pain). Before the prolonged stand, maximal hip abduction strength, side bridge hold endurance and hip abduction range of motion were measured bilaterally. Surface electromyography was collected from the gluteus medius for coactivation analysis during a prolonged stand for 70 min. Low back pain was rated every 10 min on a visual analogue scale.Results: Fourteen of 39 participants developed low back pain. The Time effect was significant for gluteus medius coactivation response (p = 0.003) and visual analogue scale score (p < 0.001). There were no significant group x time interactions. Yet athletes who developed pain had higher coactivation for the majority of the stand task.Conclusions: While female field hockey players have high agonist-antagonist coactivation patterns during prolonged standing, stand task is a useful tool to predict low back pain occurrence in players with and without history of pain. (C) 2015 Elsevier Ltd. All rights reserved.