Polymers Exhibiting Lower Critical Solution Temperatures as a Route to Thermoreversible Gelators for Healthcare

The ability to trigger changes to material properties with external stimuli, so-called “smart” behavior, has enabled novel technologies for a wide range of healthcare applications. Response to small changes in temperature is particularly attractive, where material transformations may be triggered by contact with the human body. Thermoreversible gelators are materials where warming triggers reversible phase change from low viscosity polymer solution to a gel state. These systems can be generated by the exploitation of macromolecules with lower critical solution temperatures included in their architectures. The resultant materials are attractive for topical and mucosal drug delivery, as well as for injectables. In addition, the materials are attractive for tissue engineering and 3D printing. The fundamental science underpinning these systems is described, along with progress in each class of material and their applications. Significant opportunities exist in the fundamental understanding of how polymer chemistry and nanoscience describe the performance of these systems and guide the rational design of novel systems. Furthermore, barriers to translating technologies must be addressed, for example, rigorous toxicological evaluation is rarely conducted. As such, applications remain tied to narrow fields, and advancements will be made where the existing knowledge in these areas may be applied to novel problems of science.     

Comparative evaluation between E-Glass and hemp fiber composites application in rotorcraft interiors

The present paper describes concepts and a preliminary project of a helicopter device, to investigate the use of natural fiber composites for semi-structural applications, such as electronic racks. The aim of the study consists on the evaluation of the substitution of the steel electronic rack, mounted on the helicopter Eurocopter AS 350 Écureuil, with a new version, utilizing hemp fabric/epoxy composite material. This replacement will permit to have an environmental friendly product and lower disposal costs and weight. Lower weight for helicopters and more in general for aircraft means lower fuel consumption, lower pollution and costs. The new rack has been designed using structural static and dynamic analysis through Finite Element Method (FEM). Results are promising from the structural point of view. In fact, a weight reduction of 8.01 kg (55.6%) with respect to steel has been obtained without significantly increasing the production cost. A comparison with glass fabric/epoxy composites is also provided. The results for both the composite materials are very similar, but the advantages for the environment demonstrate that is worthy choosing natural fiber composites configuration.     

Effects of carbon nanofibers (CNFs) on thermal and interlaminar shear responses of E-glass/polyester composites

A high intensity ultrasonic liquid processor was used to infuse 0.1–0.4 wt.% carbon nanofibers (CNFs) into the polyester matrix which was then mixed with a catalyst using a high speed mechanical agitator. Both conventional and nanophased glass fiber reinforced polyester composites (GRPCs) were fabricated using the vacuum assisted resin transfer molding (VARTM) process. Scanning electron microscope (SEM) revealed best dispersion of CNFs in the 0.2 wt.% CNF-loaded resin. Proper resin flow and impregnation of the glass fibers were also seen in the SEM micrographs. DMA studies exhibited about 49.5% increase in the storage modulus and about 3 °C increase in the glass transition temperature (T_g) due to the incorporation of CNFs into the GRPC. TMA studies also showed better thermal stability and lower thermal expansion in the CNF-loaded GRPC. CNF-loaded GRPC showed higher ILSS due to better interfacial bonding between the fiber and matrix due to the presence of CNFs. Fracture morphology studied by both optical microscope (OM) and SEM revealed better interfacial bonding in the CNF-loaded GRPC.     

Dilemmas in the reliable estimation of the in-vitro cell viability in magnetic nanoparticle engineering: which tests and what protocols?

Magnetic nanoparticles [MNPs] made from iron oxides have many applications in biomedicine. Full understanding of the interactions between MNPs and mammalian cells is a critical issue for their applications. In this study, MNPs were coated with poly(ethylenimine) [MNP-PEI] and poly(ethylene glycol) [MNP-PEI-PEG] to provide a subtle difference in their surface charge and their cytotoxicity which were analysed by three standard cell viability assays: 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium [MTS], CellTiter-Blue and CellTiter-Glo (Promega, Southampton, UK) in SH-SY5Y and RAW 264.7 cells The data were validated by traditional trypan blue exclusion. In comparison to trypan blue manual counting, the MTS and Titer-Blue assays appeared to have consistently overestimated the viability. The Titer-Glo also experienced a small overestimation. We hypothesise that interactions were occurring between the assay systems and the nanoparticles, resulting in incorrect cell viability evaluation. To further understand the cytotoxic effect of the nanoparticles on these cells, reactive oxygen species production, lipid peroxidation and cell membrane integrity were investigated. After pegylation, the MNP-PEI-PEG possessed a lower positive surface charge and exhibited much improved biocompatibility compared to MNP-PEI, as demonstrated not only by a higher cell viability, but also by a markedly reduced oxidative stress and cell membrane damage. These findings highlight the importance of assay selection and of dissection of different cellular responses in in-vitro characterisation of nanostructures.     

Ethical Issues in Software Engineering Research: A Survey of Current Practice

In this paper we explore how the software engineering research community is currently dealing with the ethical issues that some empirical research presents. We discuss how the immaturity of the software engineering discipline is reflected in an approach to ethical issues that compares unfavourably with other more mature disciplines.We show that an analysis of recent published work measures an increase in empirical software engineering research currently being undertaken. We also discuss our survey of UK University Department Heads which explores how the software engineering research community is dealing with the ethical issues related to empirical work. Overall we found that whilst some UK Universities have taken ethical issues very seriously, others have not considered the issues.     

Social enjoyment with electronic photograph displays: Awareness and control

Two experiments are reported in which groups of three friends socialised around their own photographs. The photographs were of two types, depicting events where all three had been present, permitting reminiscing, and events where only the photographer had been present, permitting storytelling. In Experiment 1 the seating arrangement was manipulated so that the two audience members sat either behind or around the photographer. It was hypothesised that the former would lower levels of peripheral awareness within the groups, resulting in a more formal conversation and a poorer recreational experience. In Experiment 2, control over the photographs was manipulated so that either all three group members had access to a remote control (distributed control), or only the photographer did (single control). It was hypothesised that distributed control would result in less formal conversations and a better recreational experience. In both experiments, the hypotheses were supported: patterns of social interaction were significantly affected by the manipulation of awareness during storytelling, and by the manipulation of control during reminiscing. Additionally, the two manipulations were found to affect ratings of enjoyment and fun, respectively. The results are interpreted in terms of a causative model of unfolding and recounted experience.     

Assessing the UK policies for broadband adoption

Broadband technology has been introduced to the business community and the public as a rapid way of exploiting the Internet. The benefits of its use (fast reliable connections, and always on) have been widely realised and broadband diffusion is one of the items at the top of the agenda for technology related polices of governments worldwide. In this paper an examination of the impact of the UK government’s polices upon broadband adoption is undertaken. Based on institutional theory a consideration of the manipulation of supply push and demand pull forces in the diffusion of broadband is offered. Using primary and secondary data sources, an analysis of the specific institutional actions related to IT diffusion as pursued by the UK government in the case of broadband is provided. Bringing the time dimension into consideration it is revealed that the UK government has shifted its attention from supply push-only strategies to more interventional ones where the demand pull forces are also mobilised. It is believed that this research will assist in the extraction of the “success factors” in government intervention that support the diffusion of technology with a view to render favourable results if applied to other national settings.     

Adaptive partition and hybrid method in fractal video compression

Fractal image compression is a relatively recent image compression method, which is simple to use and often leads to a high compression ratio. These advantages make it suitable for the situation of a single encoding and many decoding, as required in video on demand, archive compression, etc. There are two fundamental fractal compression methods, namely, the cube-based and the frame-based methods, being commonly studied. However, there are advantages and disadvantages in both methods. This paper gives an extension of the fundamental compression methods based on the concept of adaptive partition. Experimental results show that the algorithms based on adaptive partition may obtain a much higher compression ratio compared to algorithms based on fixed partition while maintaining the quality of decompressed images.     

Effect of fiber loading on mechanical and morphological properties of cocoa pod husk fibers reinforced thermoplastic polyurethane composites

In this study, cocoa (Theobroma cacao) pod husk (CPH) fiber reinforced thermoplastic polyurethane (TPU) was prepared by melt compounding method using Haake Polydrive R600 internal mixer. The composites were prepared with different fiber loading: 20%, 30% and 40% (by weight), with the optimum processing parameters: 190 °C, 11 min, and 40 rpm for temperature, time and speed, respectively. Five samples were cut from the composite sheet. Mean value was taken for each composite according to ASTM standards. Effect of fiber loading on mechanical (i.e. tensile, flexural properties and impact strength) and morphological properties was studied. TPU/CPH composites showed increase in tensile strength and modulus with increase in fiber loading, while tensile strain was decreasing with increase in fiber loading. The composite also showed increase in flexural strength and modulus with increase in fiber content. Impact strength was deteriorated with increase in fiber loading. Morphology observations using Scanning Electron Microscope (SEM) showed fiber/matrix good adhesion.