Structure and Catalytic Activity of Gold in Low-Temperature CO Oxidation

Structures and catalytic activities of Au thin films supported at anatase TiO(2)(101)) and a Au substrate are studied by using density functional theory calculations. The results show that O(2) can hardly adsorb at flat and stepped Au thin films, even supported by fully reduced TiO(2)(101) that can highly disperse Au atoms and offer strong electronic promotion. Interestingly, in both oxide-supported and pure Au. systems, wire-structured Au can adsorb both CO and O(2) rather strongly, and kinetic analysis suggests its high catalytic activity for low-temperature CO oxidation. The d-band center of Au at the catalytic site is determined to account for the unusual activity of the wire-structured film. A generalized structural model based on the wire-structured film is proposed for active Au, and possible support effects are discussed: Selected oxide surfaces can disperse Au atoms and stabilize the formation of a filmlike structure; they may also serve as a template for the preferential arrangement of Au atoms in a wire structure under low Au coverage.

Plasmon enhanced fluorescence studies from aligned gold nanorod arrays modified with SiO2 spacer layers

Here, we demonstrate that quasi self-standing Au nanorod arrays prepared with plasma polymerisation deposited SiO2 dielectric spacers support surface enhanced fluorescence (SEF) while maintaining high signal reproducibility. We show that it is possible to find a balance between enhanced radiative and non-radiative decay rates at which the fluorescent intensity is maximized. The SEF signal optimised with a 30 nm spacer layer thickness showed a 3.5-fold enhancement with a signal variance of <15% thereby keeping the integrity of the nanorod array. We also demonstrate the decreased importance of obtaining resonance conditions when localized surface plasmon resonance is positioned within the spectral region of Au interband transitions. Procedures for further increasing the SEF enhancement factor are also discussed.

Ionic liquid solvents of perhalide type for metals for extraction radioactive metals from mineral ores.

The invention relates to a process for dissolving metals (e.g., Al, Cu, Fe, Cr, Sb, Ti, and W) in perhalide contg. ionic liqs. having the formula (I), and to the extn. of metals from mineral ores; the remediation of materials contaminated with heavy, toxic, or radioactive metals; and to the removal of heavy and toxic metals from hydrocarbon streams. In the formula (I), [X] comprises at least one perhalide anion selected from [I3]-, [BrI2]-, [Br2I]-, [ClI2]-, [ClBr2]-, [BrCl2]-, or [ICl2]-, [ClI3]-. The (Cat+) is a cationic species selected from: ammonium, azaannulenium, azathiazolium, benzimidazolium, benzofuranium, benzotriazolium, borolium, cinnolinium, diazabicyclodecenium, diazabicyclononenium, diazabicyclo- undecenium, dithiazolium, furanium, guanidinium, imidazolium, indazolium, indolinium, indolium, morpholinium, oxaborolium, oxaphospholium, oxazinium, oxazolium, iso-oxazolium, oxathiazolium, pentazolium, phospholium, phosphonium, phthalazinium, piperazinium, piperidinium, pyranium, pyrazinium, pyrazolium, pyridazinium, pyridinium, pyrimidinium, pyrrolidinium, pyrrolium, quinazolinium, quinolinium, isoquinolinium, quinoxalinium, selenozolium, sulfonium, tetrazolium, iso-thiadiazolium, thiazinium, thiazolium, thiophenium, thiuronium, triazadecenium, triazinium, triazolium, iso-triazolium, and uronium. [on SciFinder(R)]

Panning for Gold: The Standardizing Work of Filling “Autistic” Shells – Using institutional ethnography to explore textually mediated health relations in the diagnostic process of autism.

Health reform practices in Canada and elsewhere have restructured the purpose and use of diagnostic labels and the processes of naming such labels. Diagnoses are no longer only a means to tell doctors and patients what may be wrong and indicate potential courses of treatment; some diagnoses activate specialized services and supports for persons with a disability and those who provide care for them. In British Columbia, a standardized process of diagnosis with the outcome of an autism spectrum disorder gives access to government provided health care and educational services and supports. Such processes enter individuals into a complex of text mediated relations, regulated by the principles of evidence-based medicine. However, the diagnosis of autism in children is notoriously uncertain. Because of this ambiguity, standardizing the diagnostic process creates a hurdle in gaining help and support for parents who have children with problems that could lead to a diagnosis on the autism spectrum. Such processes and their organizing relations are problematized, explored and explicated below. Grounded in the epistemological and ontological shift offered by Dorothy E. Smith (1987; 1990a; 1999; 2005), this article reports on the findings of an institutional ethnographic study that explored the diagnostic process of autism in British Columbia. More specifically, this article focuses on the processes involved in going from mothers talking from their experience about their childrens problems to the formalized and standardized, and thus “virtually” produced, diagnoses that may or may not give access to services and supports in different systems of care. Two psychologists, a developmental pediatrician, a social worker – members of a specialized multidisciplinary assessment team – and several mothers of children with a diagnosis on the autism spectrum were interviewed. The implications of standardizing the diagnosis process of a disability that is not clear-cut and has funding attached are discussed. This ethnography also provides a glimpse of the implications of current and ongoing reforms in the state-supported health care system in British Columbia, and more generally in Canada, for people’s everyday doings.

Imaging and radiation effects of gold nanoparticles in tumour cells

Gold nanoparticle radiosensitization represents a novel technique in enhancement of ionising radiation dose and its effect on biological systems. Variation between theoretical predictions and experimental measurement is significant enough that the mechanism leading to an increase in cell killing and DNA damage is still not clear. We present the first experimental results that take into account both the measured biodistribution of gold nanoparticles at the cellular level and the range of the product electrons responsible for energy deposition. Combining synchrotron-generated monoenergetic X-rays, intracellular gold particle imaging and DNA damage assays, has enabled a DNA damage model to be generated that includes the production of intermediate electrons. We can therefore show for the first time good agreement between the prediction of biological outcomes from both the Local Effect Model and a DNA damage model with experimentally observed cell killing and DNA damage induction via the combination of X-rays and GNPs. However, the requirement of two distinct models as indicated by this mechanistic study, one for short-term DNA damage and another for cell survival, indicates that, at least for nanoparticle enhancement, it is not safe to equate the lethal lesions invoked in the local effect model with DNA damage events.

Gold nanoparticle surface functionalization: mixed monolayer versus hetero bifunctional peg linker

To create a clinically relevant gold nanoparticle (AuNP) treatment, the surface must be functionalized with multiple ligands such as drugs, antifouling agents and targeting moieties. However, attaching several ligands of differing chemistries and lengths, while ensuring they all retain their biological functionality remains a challenge. This review compares the two most widely employed methods of surface co-functionalization, namely mixed monolayers and hetero-bifunctional linkers. While there are numerous in vitro studies successfully utilizing both surface arrangements, there is little consensus regarding their relative merits. Animal and preclinical studies have demonstrated the effectiveness of mixed monolayer functionalization and while some promising in vitro results have been reported for PEG linker capped AuNPs, any potential benefits of the approach are not yet fully understood.

A comparison of gold nanoparticle surface co-functionalization approaches using Polyethylene Glycol (PEG) and the effect on stability, non-specific protein adsorption and internalization

To create clinically useful gold nanoparticle (AuNP) based cancer therapeutics it is necessary to co-functionalize the AuNP surface with a range of moieties; e.g. Polyethylene Glycol (PEG), peptides and drugs. AuNPs can be functionalized by creating either a mixed monolayer by attaching all the moieties directly to the surface using thiol chemistry, or by binding groups to the surface by means of a bifunctional polyethylene glycol (PEG) linker. The linker methodology has the potential to enhance bioavailability and the amount of functional agent that can be attached. While there is a large body of published work using both surface arrangements independently, the impact of attachment methodology on stability, non-specific protein adsorption and cellular uptake is not well understood, with no published studies directly comparing the two most frequently employed approaches. This paper compares the two methodologies by synthesizing and characterizing PEG and Receptor Mediated Endocytosis (RME) peptide co-functionalized AuNPs prepared using both the mixed monolayer and linker approaches. Successful attachment of both PEG and RME peptide using the two methods was confirmed using Dynamic Light Scattering, Fourier Transform Infrared Spectroscopy and gel electrophoresis. It was observed that while the 'as synthesized' citrate capped AuNPs agglomerated under physiological salt conditions, all the mixed monolayer and PEG linker capped samples remained stable at 1M NaCl, and were stable in PBS over extended periods. While it was noted that both functionalization methods inhibited non-specific protein attachment, the mixed monolayer samples did show some changes in gel electrophoresis migration profile after incubation with fetal calf serum. PEG renders the AuNP stable in-vivo however, studies with MDA-MB-231 and MCF 10A cell lines indicated that functionalization with PEG, blocks cellular uptake. It was observed that co-functionalization with RME peptide using both the mixed monolayer and PEG linker methods greatly enhanced cellular internalization compared to PEG capped AuNPs.

In Troubles and Darkness:Black Red Gold

This is an essay including annotated critical editions documenting the history of reception of this song since 1848. Published in the Liederlexikon for the AHRC and DFG funded project 'The History of Reception of the Songs of the 1848 Revolution' (2009-2013).

The Ethical Gold series

A series of five articles, published over six months in 2010, which explained the key ethical issues relating to sourcing gold. The Ethical Gold Series was written for practising jewellers, industrial jewellery manufacturers and the wider design community. The Ethical Gold Series was published in the Benchpeg Newsletter, an online jewellery industry journal, which in 2010 had over 5,500 subscribers. The material for the articles was drawn from a year of ethnographic fieldwork in the UK jewellery sector, funded by the AHRC, and field visits to preserved, operating and proposed gold mining sites in Alaska, California, Sweden, Wales and Scotland. The ethnographic fieldwork included ‘ethical gold’ promotional events, private industry meetings and jewellery trade shows and meetings with jewellery manufacturers and retailers, assayers, gold refiners and traders and environmental and fair trade campaigners.

Containing precious metals: hallmarking, minting and the materiality of gold and silver in medieval and modern England.

This book chapter extends the argument constructed by Oakley in his conference paper ‘Containing gold: Institutional attempts to define and constrict the values of precious metal objects’ presented at ‘Itineraries of the Material’, a conference held at Goethe Universitaet, Frankfurt am Main in 2011. Oakley’s chapter investigates the social forces that define the identities, social pathways and physical movement of objects made of precious metal. It presents a case study in which constitutive substance rather than the conceptual object is the key driver behind the social trajectories of numerous artefacts and their reception by contemporary audiences. This supports the main contention of the book as a whole: the need to reconsider, and when necessary challenge, the dominance of the social biography of objects in the study of material culture. Oakley’s research used historical and ethnographic approaches, including three years’ of ethnographic field research in the jewellery industry. This included training as a precious metal assayer at the Birmingham Assay Office and observing the industry and public response to government proposals to abolish the hallmarking legislation. This fieldwork was augmented by archive, library and object collection research on the histories of assaying and goldsmithing. Oakley presents an analysis of the historical development and contemporary social relevance of hallmarking, a technological process that has never previously been subject to ethnographic study, yet is fundamental to one of the UK’s creative industries.

Moralising Gold Supply Chains

During the late twentieth century the supply chains for gold were considered by the majority of consumers (when they were considered at all) to be driven by simple commercial imperatives. That notion was shattered during the first decade of the twenty-first century by the appearance of ethical campaigns, led by advocates determined to present major players in the gold industry as morally reprehensible. The ‘No Dirty Gold’ campaign sought to shift the purchasing of gold onto a moral register, in order to challenge the activities of large mining corporations. It was followed by the Fairtrade Foundation’s ‘Fairtrade Gold’ initiative, which had aspirations to support subsistence mining communities at the expense of big business. By directly targeting a luxury material and playing on its inherent social ambiguities, campaigners hoped to thoroughly moralise the purchasing of gold objects. Dr Oakley’s presentation will examine the forces behind this developing social phenomenon, describe the trajectories of a selection of major campaigns, and consider the extent to which these have impacted on public attitudes, gold miners and the actions of consumers, producers and retailers of luxury goods.