The next generation of advanced spectroscopy : surface enhanced raman scattering from metal nanoparticles

Surface enhanced Raman scattering (SERS) has enjoyed an ever growing research base since its discovery with the number of papers published using the technique and investigating the basis behind it growing exponentially year by year.[1] SERS is an advancement of Raman scattering which overcomes some of the limitations of normal Raman scattering. Raman scattering is a vibrational spectroscopy which gives molecularly specific information relating to specific molecular species. The disadvantage of Raman scattering is that it is an inherently weak process, however it can be used in aqueous solutions, due to water being a weak Raman scatterer, lending itself to analysis and study of molecules in aqueous solution including the study of biomolecules. Another major disadvantage is the fluorescence which often accompanies Raman scattering and can sometimes overwhelm the bands in the spectrum rendering the experiment useless. To overcome this, the phenomenon of surface enhanced Raman scattering can be used

Critical appreciative processes as a methodology for studying the production of consciousness

Appreciative Inquiry (AI) was developed as an approach to organization development that involves groups of people in discovering the 'best of what is' to drive social change. Several researchers, however, found that an exclusive focus on 'positive stories' is not tenable in practice. This paper explores their advocacy of ‘critical appreciative processes’ by reporting findings from a Big Lottery Research Project on the lives of Pakistani women living in Sheffield (England). Our findings track transformative learning amongst six Pakistani research assistants who ran AI workshops, Open Space events and conducted 1-to-1 interviews with thirty-nine other Pakistani women. They collectively deconstructed and reconstructed the meaning of social practices within their community, triggering both personal and collective processes of change. The paper’s value lies in the way Appreciative Inquiry, Critical Theory and Grounded Theory have been combined to theorise how critical appreciative process can advance study of the production of consciousness within a community

Appreciative inquiry as a method of transforming identity and power in Pakistani women

This paper describes a three-year action research project that used Appreciative Inquiry to work with marginalised Pakistani women living in Sheffield. The research encountered many of the difficulties and dilemmas that have been previously identified in the theory and practice of Appreciative Inquiry. However it was also successful in bringing about a significant transformation in the ability of participants to develop critical thinking; enabling them to subvert and challenge the identities that had been constructed for them by sources of power within their community and culture. The paper describes the innovative application of Appreciative Inquiry whilst bringing a new theoretical perspective which responds to the need for Appreciative Inquiry to critically address issues of power as it plays out in the life of a community

The growth of partnership in mission in global mission history during the twentieth century

Partnership in mission came to be a byword for developing missionary relationships during the twentieth century. During this time its meaning and practice changed, often imperceptibly. This is seen in the regular conferences of the International Missionary  Conference and its successors which had their origin in the International Missionary Conference held in Edinburgh, 1910. A   further problem was making the concept a reality in relationships despite great disparities in resources. This has given rise to the negative critique of the slogan as empty and meaningless

Turning up the lights - fabrication of brighter SERRS nanotags

Brighter SERRS nanotags ideal for improved SERRS imaging were prepared by the controlled addition of electrolyte producing a dimer enriched solution, which was incubated with a Raman reporter before being stabilised by a polyethylene glycol (PEG) shell

Hated without a reason - Contending with issues of human sexuality in a South African ecclesial context: A case study

The mainline churches in South Africa are in turmoil internally as a result of divisions arising out of issues related to human sexuality. These issues have serious implications for these churches, church families within them, and the relationship of these churches with one another and with the state. There is little open space for debate as discussions are hampered by a variety of theological perspectives on the authority of scripture, some of which are fixed and absolutised. This is a matter of justice for all those involved. This research article seeks to analyse the issues involved theologically and in terms of church polity, with a view of clarifying possibilities and options for a resolution of the distress and pain caused within and between members of the Christian family using the transnational context of the Uniting Presbyterian Church in Southern Africa as a case study. The concepts of critical solidarity and critical distance will be used to clarify relationships within the relevant contexts. This article is interdisciplinary and embraces the fields of Church History or Polity, Practical Theology, Missiology and Systematic Theology. Contribution: This paper seeks to analyse issues of human sexuality within a South African Christian denomination with particular attention to the matter of justice

Simulations of Solid-on-Solid Models of Spreading of Viscous Droplets

We have studied the dynamics of spreading of viscous non-volatile fluids on surfaces by MC simulations of SOS models. We have concentrated on the complete wetting regime, with surface diffusion barriers neglected for simplicity. First, we have performed simulations for the standard SOS model. Formation of a single precursor layer, and a density profile with a spherical cap shaped center surrounded by Gaussian tails can be reproduced with this model. Dynamical layering (DL), however, only occurs with a very strongly attractive van der Waals type of substrate potential. To more realistically describe the spreading of viscous liquid droplets, we introduce a modified SOS model. In the new model, tendency for DL and the effect of the surface potential are in part embedded into the dynamics of the model. This allows a relatively simple description of the spreading under different conditions, with a temperature like parameter which strongly influences the droplet morphologies. Both rounded droplet shapes and DL can easily be reproduced with the model. Furthermore, the precursor width increases proportional to the square root of time, in accordance with experimental observations. PACS: 68.10.Gw, 05.70.Ln, 61.20.Ja.Comment: to appear in Physica A (1994), standard LaTex, 20 page

Methods for nanoparticle labeling of ricin and effect on toxicity

The unique optical properties associated with nanostructured materials that support the excitation of surface plasmons offer many new opportunities for the enhanced optical investigation of biological materials that pose a security threat. In particular, ricin is considered a significant bioterrorism risk due to its high toxicity combined with its ready availability as a byproduct in castor oil production. Therefore, the development of optical techniques capable of rapid on-site toxin detection with high molecular specificity and sensitivity continues to be of significant importance. Furthermore, understanding of the ricin cell entry and intracellular pathways remains poor due to a lack of suitable bioanalytical techniques. Initial work aimed at simultaneously tackling both these issues is described where different approaches for the nanoparticle labeling of ricin are investigated along with changes in ricin toxicity associated with the labeling process

Bayesian modelling and quantification of Raman spectroscopy

Raman spectroscopy can be used to identify molecules such as DNA by the characteristic scattering of light from a laser. It is sensitive at very low concentrations and can accurately quantify the amount of a given molecule in a sample. The presence of a large, nonuniform background presents a major challenge to analysis of these spectra. To overcome this challenge, we introduce a sequential Monte Carlo (SMC) algorithm to separate each observed spectrum into a series of peaks plus a smoothly-varying baseline, corrupted by additive white noise. The peaks are modelled as Lorentzian, Gaussian, or pseudo-Voigt functions, while the baseline is estimated using a penalised cubic spline. This latent continuous representation accounts for differences in resolution between measurements. The posterior distribution can be incrementally updated as more data becomes available, resulting in a scalable algorithm that is robust to local maxima. By incorporating this representation in a Bayesian hierarchical regression model, we can quantify the relationship between molecular concentration and peak intensity, thereby providing an improved estimate of the limit of detection, which is of major importance to analytical chemistry