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The aerosol properties of niosomes were studied using Aeroneb Pro and Omron MicroAir vibrating-mesh nebulizers and Pari LC Sprint air-jet nebulizer. Proniosomes were prepared by coating sucrose particles with Span 60 (sorbitan monostearate), cholesterol and beclometasone dipropionate (BDP) (1:1:0.1). Nano-sized niosomes were produced by manual shaking of the proniosomes in deionized water followed by sonication (median size 236nm). The entrapment of BDP in proniosome-derived niosomes was higher than that in conventional thin film-made niosomes, being 36.4% and 27.5% respectively. All nebulizers generated aerosols with very high drug output, which was 83.6% using the Aeroneb Pro, 85.5% using the Pari and 72.4% using the Omron. The median droplet size was 3.32μm, 3.06μm and 4.86μm for the Aeroneb Pro, Pari and Omron nebulizers respectively and the "fine particle fraction" (FPF) of BDP was respectively 68.7%, 76.2% and 42.1%. The predicted extrathoracic deposition, based on size distribution of nebulized droplets was negligible for all devices, suggesting all of them are potentially suitable for pulmonary delivery of niosomes. The predicted drug deposition in the alveolar region was low using the Omron (3.2%), but greater using the Aeroneb Pro (17.4%) and the Pari (20.5%). Overall, noisome-BDP aerosols with high drug output and FPF can be generated from proniosomes and delivered using vibrating-mesh or air-jet nebulizers.

Ultradeformable liposomes are stress-responsive phospholipid vesicles that have been investigated extensively in transdermal delivery. In this study, the suitability of ultradeformable liposomes for pulmonary delivery was investigated. Aerosols of ultradeformable liposomes were generated using air-jet, ultrasonic or vibrating-mesh nebulizers and their stability during aerosol generation was evaluated using salbutamol sulphate as a model hydrophilic drug. Although delivery of ultradeformable liposome aerosols in high fine particle fraction was achievable, the vesicles were very unstable to nebulization so that up to 98% drug losses were demonstrated. Conventional liposomes were relatively less unstable to nebulization. Moreover, ultradeformable liposomes tended to aggregate during nebulization whilst conventional vesicles demonstrated a "size fractionation" behaviour, with smaller liposomes delivered to the lower stage of the impinger and larger vesicles to the upper stage. A release study conducted for 2 h showed that ultradeformable liposomes retained only 30% of the originally entrapped drug, which was increased to 53% by inclusion of cholesterol within the formulations. By contrast, conventional liposomes retained 60-70% of the originally entrapped drug. The differences between ultradeformable liposomes and liposomes were attributed to the presence of ethanol or Tween 80 within the elastic vesicle formulations. Overall, this study demonstrated, contrary to our expectation, that materials included with the aim of making the liposomes more elastic and ultradeformable to enhance delivery from nebulizers were in fact responsible for vesicle instability during nebulization and high leakage rates of the drug.

In order to gain an insight into the mechanism of antimicrobial peptide action, aurein 2.5 and modelin-5 were studied. When tested against Staphylococcus aureus, aurein 2.5 showed approximately 5-fold greater efficacy even though the higher net positive charge and higher helix stability shown by modelin-5 would have predicated modelin-5 to be the more effective antimicrobial. However, in the presence of S. aureus membrane mimics, aurein 2.5 showed greater helical content (75% helical) relative to modelin-5 (51% helical) indicative of increase in membrane association. This was supported by monolayer data showing that aurein 2.5 (6.6mNm−1) generated greater pressure changes than modelin-5 (5.3mNm−1). Peptide monolayers indicted that modelin-5 formed a helix horizontal to the plane of an asymmetric interface which would be supported by the even distribution of charge and hydrophobicity along the helical long axis and facilitate lysis by non-specific membrane binding. In contrast, a groove structure observed on the surface of aurein 2.5 was predicted to be the cause of enhanced lipid binding (Kd=75μM) relative to modelin-5 (Kd=118μM) and the balance of hydrophobicity along the aurein 2.5 long axis supported deep penetration into the membrane in a tilt formation. This oblique orientation generates greater lytic efficacy in high anionic lipid (71%) compared to modelin-5 (32%).

There are increasing demands for higher levels of data assurance in higher education. This paper explores some of the drivers for this trend, and then explains what stakeholders mean by the concept of data assurance, since this has not been well defined previously. The paper captures insights from existing literature, stakeholders, auditors, and the university case experience of the authors to produce a logical model of data assurance. The model seeks to make the best use of scarce resources to deliver the stakeholders' assurance expectations, reducing redundancy and minimising the risks of omission. A logical and layered approach to the problem best delivers these outcomes. The paper concludes with a consideration of implementation issues, and demonstrates how traditional differences between academics and administrators in this difficult area may be addressed. While the paper is located in the English context, the principles will have wider applicability under other regulatory regimes.

A better understanding of protein adsorption onto surfaces of materials is required to control biocompatibility and bioactivity. Diamond-like carbon (DLC) is known to have excellent biocompatibility. Various samples of a-C:H and silicon-doped a-C:H thin films (Si-DLC) were deposited onto silicon substrates using plasma-enhanced chemical vapour deposition (PECVD). Subsequently, the adsorption of the simplest amino acid glycine onto the surfaces of the thin films was investigated to elucidate the mechanisms involved in protein adhesion. The physicochemical characteristics of the surfaces, before and after adsorption of glycine, were investigated using Raman spectroscopy and atomic force microscopy (AFM). The Raman study highlighted a slight decrease in the I D/I G ratio with increasing the silicon dopant levels. Following exposure to glycine solutions, the presence of bands at ~1735 and ~1200 cm−1 indicates that the adsorption of glycine onto the surfaces has taken place. Glycine was bound to the surfaces via both deprotonated carboxyl and protonated amino groups whilst, as the silicon content in the DLC film increased the adsorption of glycine decreased. AFM analysis showed that the surface roughness increased following exposure to glycine. These results show that at low silicon doping the adsorption of the amino acid was enhanced whilst increased doping levels led to a reduced adsorption compared to undoped DLC. Therefore, doping of DLC may provide an approach to control the protein adsorption.

Several human neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease and Familial Amyloidotic Polyneuropathy, have long been associated with, structural and functional changes in disease related proteins leading to aggregation into amyloid fibrils. Such changes can be triggered by post-translational modifications. Methylglyoxal modifications have been shown to induce the formation of small and stable native-like aggregates in the case of the amyloidogenic proteins insulin and α-synuclein. However, the fundamental biophysical mechanism underlying such methylglyoxal-induced protein aggregation is not yet fully understood. In this work cytochrome c (Cyt c) was used as a model protein for the characterization of specific glycation targets and to study their impact on protein structure, stability, and ability to form native-like aggregates. Our results show that methylglyoxal covalently modifies Cyt c at a single residue and induces early conformational changes that lead to the formation of native-like aggregates. Furthermore, partially unfolded species are formed, but do not seem to be implicated in the aggregation process. This shows a clear difference from the amyloid fibril mechanisms which involve partially or totally unfolded intermediates. Equilibrium-unfolding experiments show that glycation strongly decreases Cyt c conformational stability, which is balanced with an increase of conformational stability upon aggregation. Data collected from analytical and spectroscopic techniques, along with kinetic analysis based on least-squares parameter fitting and statistical model discrimination are used to help to understand the driving force underlying glycation-induced native-like aggregation, and enable the proposal of a comprehensive thermodynamic and kinetic model for native-like aggregation of methylglyoxal glycated Cyt c.

One of the major obstacles in the development of new antimicrobial peptides as novel antibiotics is salt sensitivity. Hal18, an α-helical subunit of Halocidin isolated from Halocynthia aurantium, has been previously shown to maintain its antimicrobial activity in high salt conditions. The α-helicity of Hal18 in the presence and absence of salt was demonstrated by circular dichroism spectroscopy, which showed that the peptide was mainly unordered containing β-strands and β-turns. However, in the presence of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylserine (DMPS) vesicles, Hal18 folded to form α-helices (circa 42 %). Furthermore, the structure was not significantly affected by pH or the presence of metal ions. These data were supported by monolayer results showing Hal18 induced stable surface pressure changes in monolayers composed of DMPC (5 mN m(-1)) and DMPS (8.5 mN m(-1)), which again were not effected by the presence of metal ions or pH. It is proposed that the hydrophobic groove within its molecular architecture enables the peptide to form stable associations with lipid membranes. The balance of hydrophobicity along the Hal18 long axis would also support oblique orientation of the peptide at the membrane interface. Hence, this model of membrane interaction would enable the peptide to penetrate deep into the membrane. This concept is supported by lysis data. Overall, it would appear that this peptide is a potential candidate for future AMP design for use in high salt environments.

Host defense peptides (HDPs) are components of the innate immune system with activity against a broad range of microbes. In some cases, it appears that this activity is mediated by the ability of these peptides to permeabilize microbial membranes via the formation of amyloid associated structures. Recent evidence suggests that the naturally occurring function of the Aβ40 and Aβ42 peptides, which are causative agents of Alzheimer's disease, may be to serve as amyloidogenic HDPs. Here, it is hypothesized that the neurotoxicity of these peptides is related to aberrant use of their amyloid-mediated antimicrobial mechanisms, which provides the as yet unexplored paradigm of a relationship among HDPs, neurodegenerative disorders, and other conditions that could contribute to their understanding and remediation.—Harris, F., Dennison, S. R., Phoenix, D. A. Aberrant action of amyloidogenic host defense peptides: a new paradigm to investigate neurodegenerative disorders?

Aurein 2.5 is a naturally C-terminally amidated amphibian antimicrobial peptide. C-terminal amidation can increase efficacy and hence a comparison was made between aurein 2.5-CONH2 and its nonamidated analogue. Amidation of the C-terminal carboxyl of aurein 2.5 enhanced antimicrobial activity 2.5- fold against Klebsiella pneumonia. Our results demonstrate that both peptide analogues had high surface activities (23 mN m-1for aurein 2.5-COOH and 26 mN m-1 aurein 2.5-CONH2). Circular dichroism measurements suggest that the helical content of the amidated form, in the presence of trifluoroethanol, was significantly enhanced (33.66 % for aurein 2.5-COOH and 60.89 % aurein 2.5-CONH2). The interaction of aurein 2.5 with bacterial cell membrane mimics was investigated using Langmuir monolayers. Aurein 2.5-CONH2 induced stable surface pressure changes in monolayers formed from K. pneumonia (circa 4.7 mN m-1), however, lower surface pressure changes were observed for aurein 2.5- COOH (circa 3.8 mN m-1). The data shows that in the case of aurein 2.5, amidation is able to enhance antibacterial activity and it is proposed that the increase in effectiveness is due to stabilization of the α-helical structure at the membrane interface.

Part 1 Membrane interaction: biophysics of the membrane interface and its involvement in protein targeting and translocation amphiphilic-helices and lipid interactions signal sequences - initiators of protein translocation determinants of membrane protein topology and membrane anchoring insertion of single- and multi-spanning proteins into the bacterial cytoplasmic membrane. Part 2 Prokaryotic protein targetting and translocation: prokaryotic protein translocation protein traffic from the cytosol to the outer membrane of "Escherichia coli" "sec"-dependent prokaryotic protein secretion targeting and assembly of fimbriae. Part 3 Eukaryotic protein targeting and translocation: targeting to and translocation across the endoplasmic reticulum membrane protein localization to the endoplasmic reticulum and golgi complex import and export of proteins at the nucleus mitochondrial targeting and import translocation of proteins into and across the thylakoid membrane principles of peroxismal protein sorting and assembly targeting of glyoxysomal proteins.