Rheology of protein-stabilised emulsion gels envisioned as composite networks. 1 - Comparison of pure droplet gels and protein gels

Protein-stabilised emulsion gels can be studied in the theoretical framework of colloidal gels, because both protein assemblies and droplets may be considered as soft colloids. These particles differ in their nature, size and softness, and these differences may have an influence on the rheological properties of the gels they form. Pure gels made of milk proteins (sodium caseinate), or of sub-micron protein-stabilised droplets, were prepared by slow acidification of suspensions at various concentrations. Their microstructure was characterised, their viscoelasticity, both in the linear and non-linear regime, and their frequency dependence were measured, and the behaviour of the two types of gels was compared. Protein gels and droplet gels were found to have broadly similar microstructure and rheological properties when compared at fixed volume fraction, a parameter derived from the study of the viscosity of the suspensions formed by proteins and by droplets. The viscoelasticity displayed a power law behaviour in concentration, as did the storage modulus in frequency. Additionally, strain hardening was found to occur at low concentration. These behaviours differed slightly between protein gels and droplet gels, showing that some specific properties of the primary colloidal particles play a role in the development of the rheological properties of the gels.Comment: 27 pages, 6 figure

State-of-the-art in studies of glacial isostatic adjustment for the British Isles: a literature review

Understanding the effects of glacial isostatic adjustment (GIA) of the British Isles is essential for the assessment of past and future sea-level trends. GIA has been extensively examined in the literature, employing different research methods and observational data types. Geological evidence from palaeo-shorelines and undisturbed sedimentary deposits has been used to reconstruct long-term relative sea-level change since the Last Glacial Maximum. This information derived from sea-level index points has been employed to inform empirical isobase models of the uplift in Scotland using trend surface and Gaussian trend surface analysis, as well as to calibrate more theory-driven GIA models that rely on Earth mantle rheology and ice sheet history. Furthermore, current short-term rates of GIA-induced crustal motion during the past few decades have been measured using different geodetic techniques, mainly continuous GPS (CGPS) and absolute gravimetry (AG). AG-measurements are generally employed to increase the accuracy of the CGPS estimates. Synthetic aperture radar interferometry (InSAR) looks promising as a relatively new technique to measure crustal uplift in the northern parts of Great Britain, where the GIA-induced vertical land deformation has its highest rate. This literature review provides an in-depth comparison and discussion of the development of these different research approaches

Structural transformations and disordering in zirconolite (CaZrTi2O7) at high pressure

There is interest in identifying novel materials for use in radioactive waste applications and studying their behavior under high pressure conditions. The mineral zirconolite (CaZrTi2O7) exists naturally in trace amounts in diamond-bearing deep-seated metamorphic/igneous environments, and it is also identified as a potential ceramic phase for radionuclide sequestration. However, it has been shown to undergo radiation-induced metamictization resulting in amorphous forms. In this study we probed the high pressure structural properties of this pyrochlore-like structure to study its phase transformations and possible amorphization behavior. Combined synchrotron X-ray diffraction and Raman spectroscopy studies reveal a series of high pressure phase transformations. Starting from the ambient pressure monoclinic structure, an intermediate phase with P21/m symmetry is produced above 15.6 GPa via a first order transformation resulting in a wide coexistence range. Upon compression to above 56 GPa a disordered metastable phase III with a cotunnite-related structure appears that is recoverable to ambient conditions. We examine the similarity between the zirconolite behavior and the structural evolution of analogous pyrochlore systems under pressure.<br/

Large optical gain from four-wave mixing instabilities in semiconductor quantum wells

Based on a microscopic many-particle theory, we predict large optical gain in the probe and background-free four-wave mixing directions caused by excitonic instabilities in semiconductor quantum wells. For a single quantum well with radiative-decay limited dephasing in a typical pump-probe setup we discuss the microscopic driving mechanisms and polarization and frequency dependence of these instabilities

Are people with schizophrenia adherent to diabetes medication? A comparative meta-analysis

Individuals living with schizophrenia are 2–3 times more likely to experience type 2 diabetes mellitus. Diabetes medication adherence is essential to reduce morbidity and mortality in this population. We conducted a meta-analysis of diabetes medication adherence among people with schizophrenia, and compared this to those without schizophrenia. A systematic search strategy was used to identify all articles reporting adherence to diabetes medications among patients with schizophrenia. In total, 10 unique studies reporting data from 33,910 people with schizophrenia were included. Random effects meta-analysis showed people with schizophrenia adhered to medication on 77.3% of days prescribed (n=32080, 95%CI=73.6–81%, I2=99.2%,), and adhered on 4.6% more days per year than those without schizophrenia (p&lt;0.01, 95%CI=2.4–6.7%, I2=92.5%, schizophrenia n=19367, controls=170,853). Furthermore, 56% of individuals with schizophrenia (n=33680) were considered “adherent” (i.e. &gt;80% adherence over 12–24 month) to diabetes medication, which was significantly more than those without schizophrenia (OR=1.34, 95%CI: 1.18–1.52, p&lt;0.01). Factors which were positively associated with diabetes medication adherence were age, number of outpatient visits, along with multiple medication administration variables. Future prospective research should examine diabetes monitoring, medication prescription, and subsequent adherence in fully representative samples. Novel interventions for maximizing compliance to diabetes medication in this vulnerable population should also be explored

The Credibility Crisis in IS

A credibility crisis continues to plague the Information Systems (IS) discipline. For almost a decade, IS has struggled to obtain and maintain its stature as a highly-respected academic discipline. The recent demise of several IS programs around the world highlights the credibility crisis, as departments have been subsumed into other business disciplines, or worse yet, abandoned entirely. In a recent MIS Quarterly article, Gill and Bhattacherjee (2009) highlight some of the challenges facing IS: low student enrollments, research that is rarely discussed in our classrooms, and research that fails to make an impact in practice. While useful tactics in terms of research (Dennis et al., 2008), student recruitment (Koch and Kayworth, 2009; Looney and Akbulut, 2007), and pedagogy (Firth et al., 2008) have surfaced in the literature, a holistic strategy for addressing the credibility crisis has yet to emerge. This panel brings together a group of IS professors to offer their perspectives on a series of propositions about the Credibility Crisis in the IS Discipline, and engage in an animated debate with each other and the audience on their positions

Addressing the Credibility Crisis in IS

A credibility crisis continues to plague the information systems (IS) discipline. For decades IS has struggled to acquire and maintain its stature as a highly-respected academic discipline. The recent demise of several IS programs around the world highlights the credibility crisis, as departments have been subsumed into other business disciplines, or worse yet, abandoned entirely. In a recent MIS Quarterly article, Gill and Bhattacherjee [2009] highlight some of the challenges facing IS: low student enrollments, research that is rarely discussed in our classrooms, and research that fails to make an impact in practice. While useful tactics in terms of research [Dennis et al., 2006], student recruitment [Koch et al., 2010; Looney and Akbulut, 2007] and pedagogy [Firth et al., 2008] have surfaced, a holistic strategy for addressing the credibility crisis has yet to emerge. This article summarizes a panel discussion at the AMCIS 2010 conference, where a group of distinguished IS professors offered their unique perspectives on the challenges, origins, and solutions related to the current credibility crisis in IS

Comparative Analysis of Gene Expression in Virulent and Attenuated Strains of Infectious Bronchitis Virus at Subcodon Resolution.

Like all coronaviruses, avian infectious bronchitis virus (IBV) possesses a long, single-stranded, positive-sense RNA genome (∼27 kb) and has a complex replication strategy that includes the production of a nested set of subgenomic mRNAs (sgmRNAs). Here, we used whole-transcriptome sequencing (RNASeq) and ribosome profiling (RiboSeq) to delineate gene expression in the IBV M41-CK and Beau-R strains at subcodon resolution. RNASeq facilitated a comparative analysis of viral RNA synthesis and revealed two novel transcription junction sites in the attenuated Beau-R strain, one of which would generate a sgmRNA encoding a ribosomally occupied open reading frame (dORF) located downstream of the nucleocapsid coding region. RiboSeq permitted quantification of the translational efficiency of virus gene expression and identified, for the first time, sites of ribosomal pausing on the genome. Quantification of reads flanking the programmed ribosomal frameshifting (PRF) signal at the genomic RNA ORF1a/ORF1b junction revealed that PRF in IBV is highly efficient (33 to 40%). Triplet phasing of RiboSeq data allowed precise determination of reading frames and revealed the translation of two ORFs (ORF4b and ORF4c on sgmRNA IR), which are widely conserved across IBV isolates. Analysis of differential gene expression in infected primary chick kidney cells indicated that the host cell response to IBV occurs primarily at the level of transcription, with global upregulation of immune-related mRNA transcripts following infection and comparatively modest changes in the translation efficiencies of host genes. Cellular genes and gene networks differentially expressed during virus infection were also identified, giving insights into the host cell response to IBV infection.IMPORTANCE IBV is a major avian pathogen and presents a substantial economic burden to the poultry industry. Improved vaccination strategies are urgently needed to curb the global spread of this virus, and the development of suitable vaccine candidates will be aided by an improved understanding of IBV molecular biology. Our high-resolution data have enabled a precise study of transcription and translation in cells infected with both pathogenic and attenuated forms of IBV and expand our understanding of gammacoronaviral gene expression. We demonstrate that gene expression shows considerable intraspecies variation, with single nucleotide polymorphisms being associated with altered production of sgmRNA transcripts, and our RiboSeq data sets enabled us to uncover novel ribosomally occupied ORFs in both strains. The numerous cellular genes and gene networks found to be differentially expressed during virus infection provide insights into the host cell response to IBV infection.Wellcome Trust European Research Counci

Establishing the zero-carbon performance of compact urban dwellings

This paper presents an analysis of the zero-carbon performance of a case-study building which is representative of a growing number of new buildings that are being built on redevelopment sites in inner-city areas in the UK. Compact urban dwellings are apartment style buildings with a floor area of 50 m2 per dwelling, often based over two floors. The constraints of this type of building on achieving zero-carbon performance in the context of the Code for Sustainable Homes is discussed and the shortcomings of the code are demonstrated in terms of the target heat and electricity demand targets for the design of the building systems. A graphical representation of the simulation results is used to present the findings. It has been demonstrated that in specific urban contexts, zero-carbon performance as defined within the current UK compliance framework may be very difficult to achieve in practice given the assumptions used in the simulation here. Therefore, it is very likely that zero-carbon compact urban dwellings may require a net off-site import of electrical and/or thermal energy