Tear film lipids:dynamic composition and clinical performance

Purpose: Meibomian-derived lipid secretions are well characterised but their subsequent fate in the ocular environment is less well understood. Phospholipids are thought to facilitate the interface between aqueous and lipid layers of the tear film and to be involved in ocular lubrication processes. We have extended our previous studies on phospholipid levels in the tear film to encompass the fate of polar and non-polar lipids in progressive accumulation and aging processes on both conventional and silicone-modified hydrogel lenses. This is an important aspect of the developing understanding of the role of lipids in the clinical performance of silicone hydrogels. Method: Several techniques were used to identify lipids in the tear film. Mass-spectrometric methods included Agilent 1100-based liquid chromatography coupled to mass spectrometry (LCMS) and Perkin Elmer gas chromatography mass spectrometry (GCMS). Thin layer chromatography (TLC) was used for separation of lipids on the basis of increasing solvent polarity. Routine assay of lipid extractions from patient-worn lenses was carried out using a Hewlett Packard 1090 liquid chromatograph coupled to both uv and Agilent 1100 fluorescence detection. A range of histological together with optical, and electron microscope techniques was used in deposit analysis. Results: Progressive lipid uptake was assessed in various ways, including: composition changes with wear time, differential lipid penetrate into the lens matrix and, particularly, the extent to which lipids become unextractable as a function of wear time. Solvent-based separation and HPLC gave consistent results indicating that the polarity of lipid classes decreased as follows: phospholipids/fatty acids > triglycerides > cholesterol/cholesteryl esters. Tear lipids were found to show autofluorescence—which underpinned the value of fluorescence microscopy and fluorescence detection coupled with HPLC separation. The most fluorescent lipids were found to be cholesteryl esters; histological techniques coupled with fluorescence microscopy indicated that white spots (’’jelly bumps’’) formed on silicone hydrogel lenses contain a high proportion of cholesteryl esters. Lipid profiles averaged for 30 symptomatic and 30 asymptomatic contact lens wearers were compiled. Peak classes were split into: cholesterol (C), cholesteryl esters (CE), glycerides (G), polar fatty acids/phospholipids (PL). The lipid ratio for ymptomatic/symptomatic was 0.6 ± 0.1 for all classes except one—the cholesterol ratio was 0.2 ± 0.05. Significantly the PL ratio was no different from that of any other class except cholesterol. Chromatography indicated that: lipid polarity decreased with depth of penetration and that lipid extractability decreased with wear time. Conclusions: Meibomian lipid composition differs from that in the tear film and on worn lenses. Although the same broad lipid classes were obtained by extraction from all lenses and all patients studied, quantities vary with wear and material. Lipid extractability diminishes with wear time regardless of the use of cleaning regimes. Dry eye symptoms in contact lens wear are frequently linked to lipid layer behaviour but seem to relate more to total lipid than to specific composition. Understanding the detail of lipid related processes is an important element of improving the clinical performance of materials and care solutions.

Introduction: the media, animal conservation and environmental education

Natural History filmmaking has a long history but the generic boundaries between it and environmental and conservation filmmaking are blurred. Nature, environment and animal imagery has been a mainstay of television, campaigning organisations and conservation bodies from Greenpeace to the Sierra Club, with vibrant images being used effectively on posters, leaflets and postcards, and in coffee table books, media releases, short films and viral emails to educate and inform the general public. However, critics suggest that wildlife film and photography frequently convey a false image of the state of the world’s flora and fauna. The environmental educator David Orr once remarked that all education is environmental education, and it is possible to see all image-based communication in the same way. The Media, Animal Conservation and Environmental Education has contributions from filmmakers, photographers, researchers and academics from across the globe. It explores the various ways in which film, television and video are, and can be, used by conservationists and educators to encourage both a greater awareness of environmental and conservation issues, and practical action designed to help endangered species. This book is based on a special issue of the journal Environmental Education Research.

The media, animal conservation and environmental education

Natural History filmmaking has a long history but the generic boundaries between it and environmental and conservation filmmaking are blurred. Nature, environment and animal imagery has been a mainstay of television, campaigning organisations and conservation bodies from Greenpeace to the Sierra Club, with vibrant images being used effectively on posters, leaflets and postcards, and in coffee table books, media releases, short films and viral emails to educate and inform the general public. However, critics suggest that wildlife film and photography frequently convey a false image of the state of the world’s flora and fauna. The environmental educator David Orr once remarked that all education is environmental education, and it is possible to see all image-based communication in the same way. The Media, Animal Conservation and Environmental Education has contributions from filmmakers, photographers, researchers and academics from across the globe. It explores the various ways in which film, television and video are, and can be, used by conservationists and educators to encourage both a greater awareness of environmental and conservation issues, and practical action designed to help endangered species. This book is based on a special issue of the journal Environmental Education Research.

Critical practice and the public pedagogy of environmental and conservation media

Natural History filmmaking has a long history but the generic boundaries between it and environmental and conservation filmmaking are blurred. Nature, environment and animal imagery has been a mainstay of television, campaigning organisations and conservation bodies from Greenpeace to the Sierra Club, with vibrant images being used effectively on posters, leaflets and postcards, and in coffee table books, media releases, short films and viral emails to educate and inform the general public. However, critics suggest that wildlife film and photography frequently convey a false image of the state of the world’s flora and fauna. The environmental educator David Orr once remarked that all education is environmental education, and it is possible to see all image-based communication in the same way. The Media, Animal Conservation and Environmental Education has contributions from filmmakers, photographers, researchers and academics from across the globe. It explores the various ways in which film, television and video are, and can be, used by conservationists and educators to encourage both a greater awareness of environmental and conservation issues, and practical action designed to help endangered species. This book is based on a special issue of the journal Environmental Education Research.

Porous tin film synthesized by electrodeposition and the electrochemical performance for lithium-ion batteries

Porous tin films as anode for lithium-ion batteries are electrodeposited on graphite paper. Homogeneous tin films with significant void space accommodate the volume change during tin lithiation/delithiation. Through adjusting the electrodeposition currents and time, the morphologies and void space of tin films on graphite paper are controllable. At fixed electrodeposition current densities, the prolonged electrodeposition time plays the role in growing big tin particles and resulting the disappearance of void space among tin particles. The increased electrodeposition current plays the role to increase the quantity of tin seeds in thickness of tin film, and the void space among tin particles remains but the thick film limits its electrochemical performance. The tin films electrodeposited at an optimized current densities and for an optimized electrodeposition time, present the best electrochemical performance, because the tin nanoparticles are well dispersed on graphite substrate including void space. The tin film electrodeposited at 0.2 A cm-2 for 2 min shows the capacity of 1.0 mAh cm-2 after 50 charge/discharge cycles. The void space of tin film is very important for the best capacity and cyclic ability. The metallic tin film produced at 0.4 A cm-2 for 3 min remains the uniform and microporous structure after charge/discharge for 50 cycles.

Ionized cluster beam deposition, and thin film analysis

In 1972 the ionized cluster beam (ICB) deposition technique was introduced as a new method for thin film deposition. At that time the use of clusters was postulated to be able to enhance film nucleation and adatom surface mobility, resulting in high quality films. Although a few researchers reported singly ionized clusters containing 10$\sp2$-10$\sp3$ atoms, others were unable to repeat their work. The consensus now is that film effects in the early investigations were due to self-ion bombardment rather than clusters. Subsequently in recent work (early 1992) synthesis of large clusters of zinc without the use of a carrier gas was demonstrated by Gspann and repeated in our laboratory. Clusters resulted from very significant changes in two source parameters. Crucible pressure was increased from the earlier 2 Torr to several thousand Torr and a converging-diverging nozzle 18 mm long and 0.4 mm in diameter at the throat was used in place of the 1 mm x 1 mm nozzle used in the early work. While this is practical for zinc and other high vapor pressure materials it remains impractical for many materials of industrial interest such as gold, silver, and aluminum. The work presented here describes results using gold and silver at pressures of around 1 and 50 Torr in order to study the effect of the pressure and nozzle shape. Significant numbers of large clusters were not detected. Deposited films were studied by atomic force microscopy (AFM) for roughness analysis, and X-ray diffraction.^ Nanometer size islands of zinc deposited on flat silicon substrates by ICB were also studied by atomic force microscopy and the number of atoms/cm$\sp2$ was calculated and compared to data from Rutherford backscattering spectrometry (RBS). To improve the agreement between data from AFM and RBS, convolution and deconvolution algorithms were implemented to study and simulate the interaction between tip and sample in atomic force microscopy. The deconvolution algorithm takes into account the physical volume occupied by the tip resulting in an image that is a more accurate representation of the surface.^ One method increasingly used to study the deposited films both during the growth process and following, is ellipsometry. Ellipsometry is a surface analytical technique used to determine the optical properties and thickness of thin films. In situ measurements can be made through the windows of a deposition chamber. A method for determining the optical properties of a film, that is sensitive only to the growing film and accommodates underlying interfacial layers, multiple unknown underlayers, and other unknown substrates was developed. This method is carried out by making an initial ellipsometry measurement well past the real interface and by defining a virtual interface in the vicinity of this measurement. ^

A mitochondrial species identification assay for Australian blacktip sharks (Carcharhinus tilstoni, C. limbatus and C. amblyrhynchoides) using real-time PCR and high-resolution melt analysis

Tropical Australian shark fisheries target two morphologically indistinguishable blacktip sharks, the Australian blacktip (Carcharhinus tilstoni) and the common blacktip (C. limbatus). Their relative contributions to northern and eastern Australian coastal fisheries are unclear because of species identification difficulties. The two species differ in their number of precaudal vertebrae, which is difficult and time consuming to obtain in the field. But, the two species can be distinguished genetically with diagnostic mutations in their mitochondrial DNA ND4 gene. A third closely related sister species, the graceful shark C. amblyrhynchoides, can also be distinguished by species-specific mutations in this gene. DNA sequencing is an effective diagnostic tool, but is relatively expensive and time consuming. In contrast, real-time high-resolution melt (HRM) PCR assays are rapid and relatively inexpensive. These assays amplify regions of DNA with species-specific genetic mutations that result in PCR products with unique melt profiles. A real-time HRM PCR species-diagnostic assay (RT-HRM-PCR) has been developed based on the mtDNA ND4 gene for rapid typing of C. tilstoni, C. limbatus and C. amblyrhynchoides. The assay was developed using ND4 sequences from 66 C. tilstoni, 33. C. limbatus and five C. amblyrhynchoides collected from Indonesia and Australian states and territories; Western Australia, the Northern Territory, Queensland and New South Wales. The assay was shown to be 100% accurate on 160 unknown blacktip shark tissue samples by full mtDNA ND4 sequencing.

Disorderly categories in picture postcards from colonial Papua and New Guinea

At the turn of the century in Melbourne, a notice typed on the verso of a postcard stated that the South Yarra Baptist Young Men's class was meeting on the following Sunday at 2.45 p.m. The card, published in the United Kingdom, was numbered 51828 in the Valentine series of Papuan postcards.1 The image, a photograph of Hanuabada village taken in the early 1880s, and the text, written early in 1900, are contradictory and constitute separate realms of evidence that invite a renegotiation of meaning, analysis, and interpretation of the relationships between images, tourism, colonial rule, and ethnographic knowing. The visual evidence suggests the postcard may have played an ethnographic, educative role in the public understanding of Papua, which had just become an Australian Territory and was not yet well known. It is also suggestive of educative roles related to mission endeavours, subimperialist ambitions and the new tourist traffic through the ports of Port Moresby, Samarai, and Rabaul.

Lady Nugent and Tom Cringle on the veranda : early nineteenth century observations on a Caribbean architectural feature

This study of the veranda as seen through the eyes of Lady Maria Nugent and Michael Scott, alias Tom Cringle, clearly demonstrates the important role that the piazza, as it was then more commonly known, played in the life of early nineteenth century Caribbean colonial society. The popularity of the veranda throughout the region, in places influenced by different European as well as African cultures, and among all classes of people, suggests that the appeal of this typical feature was based on something more than architectural fashion. A place of relative comfort in hot weather, the veranda is also a space at the interface of indoors and outdoors which allows for a wide variety of uses, for solitary or small or large group activities, many of which were noted by Nugent and Scott. Quintessentially, the veranda is a place in which to relax and take pleasure, not least of which is the enjoyment of the prospect, be it a panoramic view, a peaceful garden or a lively street scene. Despite the great changes in the nature of society, in the Caribbean and in many other parts of the world, the veranda and related structures such as the balcony continue to play at least as important a role in daily life as they did two centuries ago. The veranda of today’s Californian or Australian bungalow, and the balcony of the apartment block in the residential area of the modern city are among the contemporary equivalents of the lower and upper piazzas of Lady Nugent’s and Tom Cringle’s day.